NISTIR 88-3907

U.S. Department of Commerce

National Institute of Standards and Technology

NISTIR 88-3907 Center for

Chemical

Technology

1988

Technical Activities

December 1988

Jesse Hord, Acting Director

Center for Chemical Technology

National Measurement Laboratory

U.S. Department of Commerce, C. William Verity, Secretary

Ernest Ambler, Acting Under Secretary for Technology

National Institute of Standards and Technology,

Raymond G. Kammer, Acting Director

ABSTRACT

Technical research activities performed by the Center for Chemical

Technology during the Fiscal Year 1988 are summarized herein. These

activities include work in the general categories of measurements (standards,

processes, and equipment design), properties (thermophysical, thermochemical,

and kinetic) , and biotechnology (protein engineering and separations) . They

embody: development and improvement of measurement standards, measurement

principles, and calibration services for pressure, temperature, volumetric

and mass flow rates, liquid volume and density, humidity, and airspeed;

generation (via accurate measurements and advanced predictive models) of

reliable reference data for thermophysical, thermochemical, and kinetic

properties of pure fluids, fluid mixtures, and solids of industrial and

environmental importance; provision of fundamental understanding of protein

structure- function and advanced technology for commercial scale separation of

proteins; and development of improved correlations, models, and measurement

techniques for complex flows, heat and mass transport, mixing, and chemically

reacting flows of interest in modern unit operations.

Keywords: biotechnology; calibrations; chemical engineering; chemistry;

data; flow; fluid properties; kinetics; measurement standards; pressure;

process measurement; sensors; separations; solid properties; temperature;

thermochemistry; thermophysics; unit operations.

iii
INTRODUCTION

This document summarizes technical research activities of the Center for

Chemical Technology (CCT) during Fiscal Year 1988 (October 1, 1987 through

September 30, 1988). This Center is one of four such Centers in the National

Measurement Laboratory of the National Institute of Standards and Technology.

The activities of the Center are focused on chemistry and chemical

engineering in support of the chemical and related industries (including

chemical, petrochemical, biochemical, petroleum, gas, energy, food and drug,

paper, etc.). The goal of the Center is to provide the scientific foundation

for reliable measurements and data bases that assure equity in domestic and

international trade and enable innovation as well as improved design and

control of chemical and related processes. The Center's research contributes

significantly to the ability of U.S. industry to compete in world markets.

This summary report is presented in six sections, one for each

participating Division in the Center: Chemical Thermodynamics, Chemical

Kinetics, Chemical Engineering Science, Thermophysics, Chemical Process

Metrology, and Temperature and Pressure. It summarizes project activities,

cites primary publications, and closes with lists of conferences and

workshops hosted, sponsored, or organized by the Center. CARB (Center for

Advanced Research in Biotechnology) is a cooperative effort with the

University of Maryland and Montgomery County, Maryland, and CARB's Fiscal

Year 1988 research activities are included with those of its parent Division,

the Chemical Thermodynamics Division.

The Center for Chemical Technology is comprised of Divisions formerly

contained in the Center for Chemical Engineering, Center for Chemical

Physics, and Center for Basic Standards within the National Bureau of

Standards (NBS) . During the summer of 1988 the NBS name was also changed to

the National Institute of Standards and Technology (NIST)

.

If additional information is desired on any technical project reported

herein, readers should address their inquiries to the appropriately

identified project staff via the Center for Chemical Technology, National

Institute of Standards and Technology, B256 Physics Building, Gaithersburg,

MD 20899.

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TABLE OF CONTENTS

ABSTRACT iii

INTRODUCTION iv

TECHNICAL ACTIVITIES OF THE

CHEMICAL THERMODYNAMICS DIVISION

1. Introduction 1

2. Goal 2

3 . Group Functions 2

4 . Selected Project Summaries 3

5. Publications 17

6. Conferences 22

TECHNICAL ACTIVITIES OF THE

CHEMICAL KINETICS DIVISION

1. Introduction 23

2. Goal 23

3. Group Functions 24

4 . Selected Project Summaries 24

5. Publications 42

TECHNICAL ACTIVITIES OF THE

CHEMICAL ENGINEERING SCIENCE DIVISION

1. Introduction 55

2. Goal 56

3. Group Functions 57

4 . Selected Project Summaries 58

5. Publications 67

6. Conferences 71

TECHNICAL ACTIVITIES OF THE

THERMOPHYSICS DIVISION

1. Introduction 73

2. Goal 74

3. Group and Program Functions 74

4 . Selected Project Summaries 75

5. Publications 92

6. Conferences and Workshops 100

v
TECHNICAL ACTIVITIES OF THE

CHEMICAL PROCESS METROLOGY DIVISION

1. Introduction 101

2. Goal 103

3 . Group Functions 103

4. Selected Project Summaries 105

5. Publications 122

6. Conferences and Workshops 127

TECHNICAL ACTIVITIES OF THE

TEMPERATURE AND PRESSURE DIVISION

1. Introduction 129

2. Goal 130

3. Group and Program Functions 131

4. Selected Project Summaries 133

5. Publications 152

6. Conferences and Workshops 154

vi
TECHNICAL ACTIVITIES

OF THE

CHEMICAL THERMODYNAMICS DIVISION

S. Abramowitz, Chief

1. INTRODUCTION

The Chemical Thermodynamics Division provides measurement techniques,

concepts, and data on the energetics and equilibria of chemical processes.

Chemical thermodynamics is used to predict equilibria in chemical reactions,

thermodynamic properties of high temperature refractory materials and gases,

activities of aqueous solutions used in technologies varying from power

generation and electrorefining to biotechnology. This Division develops the

models necessary for correlating structure with thermodynamic properties,

develops the science of calorimetry in order to obtain precise data from the

microwatt to megawatt levels, carries out precise thermodynamic measurements,

including those on Standard Reference Materials, develops the measurement

capabilities for molecular structure determinations, and critically evaluates

thermodynamic data in all phases for the use of industry, government, and

academia

Current emphasis is directed toward the needs of the emerging

biotechnology industry. This Division is developing measurement and

computational techniques and data bases for the crystalline structure of

biomolecular species including enzymes, enzyme - substrate complexes, and DNA

species. Efforts are under way to understand, on a molecular level, the

relationships between biological function, structure, and energetics. The

thermochemistry of generic processes of interest to biochemistry and

biotechnology is being studied in order to develop standards and provide key

data, to develop quantitative models for the energetics of these processes

and estimation schemes of demonstrated reliability for the concomitant

thermodynamic properties.

Research needs of four federal agencies and one industrial trade

association are being addressed by the Division. Funding is received from

the Department of Energy for development of data bases for nuclear waste and

for determining chlorine mass balance during the combustion of municipal

solid wastes. Combustion calorimetric data and estimation schemes and

thermochemical tables are being developed for agencies of the Department of

Defense. Computer algorithms and evaluated data bases for aqueous

thermodynamics are being developed for the AIChE's Design Institute for

Physical Property Data (DIPPR) . In addition, the Division collaborates on

problems of mutual interest with the Chemical Kinetics, Molecular

Spectroscopy, and Thermophysics Divisions, the Center for Analytical

Chemistry and the Institute for Materials Science and Engineering. The

Division is also active in the ASTM, ANSI, ASME, CODATA, IUPAC and IAEA.

1
2. GOAL

The goal of the Division is to provide state-of-the-art measurement

techniques, concepts, data, and data-predictive methods for chemical

thermodynamic properties of chemical systems of industrial and environmental

importance

Major objectives of the Chemical Thermodynamics Division include:

• Application of the science of calorimetry to the needs of

existing and new technologies through the design of novel

calorimeters and the development of improved procedures

to obtain enhanced measurement precision and accuracy.

• Development and certification of thermodynamic and

physical properties of Standard Reference Materials for

the use of existing and emerging technologies.

• Measurement of the thermochemical properties of key

chemical species and processes including bioprocesses

and phase transitions of aqueous biomolecular

species

• Provision of critically evaluated compilations of the

thermodynamic properties of inorganic, organic, and

bio-organic compounds in the gaseous, liquid, solid,

and aqueous phases.

• Development of estimation schemes for the prediction of

thermodynamic properties of organic, inorganic, and bioorganic species in the gaseous, liquid, solid, and

aqueous phases.

• Development of measurement and computational methodology

for the determination of the structure of

biomacromolecular species using the techniques of x-ray

diffraction.

• Development of experimental methodologies to determine

the relationships between biological function,

structure, and energetics of prototypical biological

species including proteins and nucleic acids.

3. GROUP FUNCTIONS

The research of the Division is performed within three groups.

• Chemical Thermodynamics Measurements - E.S. Domalski, Group

Leader

This Group develops methodology for the measurement of thermodynamic and

2
physical properties of organic chemical species, refractory materials, and

large samples of heterogeneous materials. The Group develops new

experimental techniques and provides key measurements and reliable estimation

schemes. Major non-CCT sponsors of this research include the NIST Offices of

Standard Reference Materials and Standard Reference Data, the Department of

Energy, the Office of Naval Research, and the U.S. Army.

• Bio thermodynamics and Biomolecular Structure - S. Abramowitz, Group

Leader

This Group develops experimental methodologies and computer algorithms,

including computer graphics, for the determination of the structure of

biomolecular species (including proteins, enzymes, enzyme -substrate

complexes, and DNA species); studies the relationships between biomolecular

structure, function, and energetics; and determines the thermodynamic

properties of prototypical biochemical species and processes of interest to

biochemistry and biotechnology. A unique data base on the preparation,

properties, and x-ray structure of biological macromolecules has been

established.

• Chemical Thermodynamic Data Centers - M.W. Chase, Group Leader

This Group provides critically evaluated chemical thermodynamic data,

estimation schemes, computer models and algorithms for inorganic and organic

species in the solid, liquid, gaseous and aqueous phases. It evaluates data

of interest to chemical, defense, bioprocessing and energy related

technologies. Included in its non-CCT sponsors are the NIST Office of

Standard Reference Data, Department of Energy, JANNAF Combustion Subcommittee

(DOD) and NASA.

4. SELECTED PROJECT SUMMARIES

Chlorine Mass Balance Studies During the Combustion of RDF

E.S. Domalski, K.L. Churney, T.J. Buckley, A.E. Ledford, Jr.

The sources and fate of chlorine during the combustion of municipal

solid waste (MSW) and refuse -derived fuels (RDF) continue to be an important

environmental consideration which impacts significantly upon MSW and RDF as

alternative fuels. Combustion measurements have been carried out in the

multi -kilogram capacity combustor in excess air (25-50% oxygen) . The purpose

of the research during FY88 has been to determine the distribution of

chlorine between the reaction products and to obtain chlorine mass balances

for the combustion of RDF. Chlorine analysis of the combustion products

showed that 80-85% of the chlorine is transfered to the volatile products as

HC1 and 10-15% of the chlorine resides in the ash. The addition of lime to

the input RDF sample increases the amount of chlorine that is trapped in the

ash residue. About 7-9% lime in the input RDF sample will increase the

chlorine content in the ash from 10-15% to 45-50%. It has been demonstrated

that lime is a very good binding agent for maintaining the integrity and

3
storability of dense RDF pellets. Combustion of synthetic samples composed

of shredded and milled magazine print with 2% sodium chloride (NaCl) or

polyvinyl chloride (PVC) showed no significant changes in the distribution of

chlorine in the products between the volatile effluent phase and the ash,

i.e., 80-85% chlorine in the effluent as HC1 and 10-15% in the ash.

Two papers were presented at the 13th National Waste Processing

Conference in Philadelphia in May 1988; "Chlorine Mass Balance during the

Combustion of RDF" and "Evaluation of Data on Higher Heating Values and

Elemental Analysis for RDF."

Combustion measurements have been performed on multi -kilogram samples of

coal, mixtures of coal and RDF, and mixtures of coal with RDF and lime. The

distribution of chlorine in the products of the mixtures will be compared to

the results of similar large scale tests carried out in a boiler at the

Argonne National Laboratory. The influence of the addition of catalysts,

such as MnC> 2 , to the lime upon the chlorine distribution in the combustion

products will be studied.

Calorimetric experiments were conducted to convert the multi -kilogram

capacity combustor into a multi-kilogram capacity aneroid flow calorimeter.

ASME will use this information to prepare standard performance test codes for

determining the heating value of MSW or RDF. Conversion of the combustor to

an aneroid flow calorimeter has provided energy balance closure with

uncertainties of about 3%.

High Temperature Heat Capacity Calorimetry

D.A. Ditmars

Relative enthalpy data were obtained on pure tin and zinc in the liquid

and solid phases in an isothermal phase-change calorimeter. Values for

temperature of fusion, Tfus , and enthalpy of fusion, AHfus , for tin were

derived from the data for certification of SRM 2220 (Sn)In the data

analysis, a hitherto unpublished approach to deriving the temperature of

fusion from non-equilibrium partial-melting data was used. Similar

measurements on zinc were started in FY 1988 and are projected for completion

in FY 1989. Work is scheduled to measure the high temperature of fusion and

enthalpy of fusion of two other candidate SRM's, aluminum and indium, during

FY 1989.

Relative enthalpy data were obtained for barium and strontium between

room temperature and their fusion temperatures.

A chapter on the design of drop calorimeters was completed and submitted

for publication to the Committee of the European Thermophysics Conferences

Organization.

4
Precision Oxygen Bomb Calorimetry

D. Kirklin, E.S. Domalski

Precision bomb calorimetry is the most reliable source of accurate

enthalpies of formation. Enthalpies of formation have been determined for

strained organic compounds, an organic phosphorus compound, and purine

nucleosides. Precise and accurate enthalpies of formation are needed to

determine the amount of strain energy in strained organic molecules. The

lack of data on organic phosphorus compounds has hindered the development of

an estimation scheme for important organic phosphorus compounds. A better

understanding of the energetics of important biological species can be

attained from the enthalpies of formation of important biological compounds.

Bomb calorimetric measurements have been performed on three important

chemical systems. Preliminary measurements have been completed on a sample

of 1 , 4-dimethyldicarboxylate cubane . A preliminary value of the strain

energy in the cubane system has been calculated. Measurements have been

completed on triphenylphosphate . This is the third compound of a series that

has allowed derivation of group energy contribution values to estimate the

enthalpy of formation of organic phosphorus compounds containing phenyl

groups. Enthalpies of formation for the ribonucleosides of purine, adenine,

and guanine have been derived from bomb calorimetric data.

Experimental results have been presented at one international

conference, one national conference, and a contractors' conference for

chemical defense research. Three papers have been prepared and one paper is

in the final editorial stage.

A study of organic phosphorus compounds will be continued with alkyl

phosphorus compounds. Advances in bomb calorimetry of organic phosphorus

compounds will allow study of energetic biological compounds containing

phosphorus. Strain energy studies will be continued on pure organic

compounds to provide a better understanding of the energetics of strained

organic species.

Bomb Calorimetry for Biotechnology and SRM Development

J.C. Colbert, E.S. Domalski, E. Diaz

The work on the characterization of hexaglycine was completed and

included collaborations with NIST scientists B. Coxon and D. VanderHart on

the NMR characterization. A manuscript was prepared and submitted for

publication.

Modifications were begun on the microbomb calorimeter acquired from

Margret Mansson (University of Lund) to incorporate an oscillating quartz

thermometer as our temperature measuring device. This apparatus will be used

in the study of strained organic species and prototypical biochemical species

including peptides.

5
Preliminary calorimetric measurements were made on DL-leucyl-DL- leucine

and L-valyl-L-valine . Work will be ongoing to acquire CO 2 recoveries for DLalanyl-DL- alanine and glycylglycine

A preliminary check on the internal energy of combustion of a candidate

material for renewal of SRM Benzoic Acid 3 9j was made and a report submitted

to OSRM. Measurements were completed and reports submitted to OSRM on SRM

1548 Mixed Diet, SRM 2692 1% Sulfur in Coal, and SRM 1632b Trace Elements in

Coal

Defining and Designing DNA Sequences that Function as Origins of

DNA Replication

K, McKenney, J. Hoskins (University of Maryland), S. Wickner (National Cancer

Institute)

This project is directed toward defining the DNA sequences required for

phage PI DNA replication. The origin of DNA replication for PI has been

restricted to a 310-base-pair fragment of DNA that contains a large number of

interesting sequences and structures. These include two 9 -base -pair dnaA

protein binding sites, five 19-base-pair phage repA protein binding sites,

and five GATC sequences that are sites for methylation by the dam methylase

enzyme. We have defined the minimal origin of replication by making a family

of deletions into the 310-base-pair fragment from each end of the fragment

using Bal31 nuclease.

A 2000-base-pair fragment of PI DNA was cloned and sequenced in M13

vectors. DNA was prepared, and the small 310-base -pair minimal PI ori DNA

was isolated and recloned in both orientations into M13 vectors. Bal31

nuclease digests were made and analyzed and appropriate deletion time points

were chosen. The digests were transformed into cells to purify individual

molecules (clones), amplified, and characterized by DNA sequence analysis.

The DNA sequence defines the exact DNA base of each deletion. A number of

deletions into each of the control sites were isolated, and double - stranded

DNA molecules were purified and tested for their ability to function as an

origin of replication in an in vitro replication assay. We have discovered

that there is an absolute requirement for dnaA binding sites and a minimum of

two and one half repA DNA binding sites. In addition, the dnaA binding sites

have been modified in four ways. First, the spacing between the dnaA sites

and the repA sites was increased. Second, the dnaA sites were "turned

around" with respect to the repA binding sites. Third, the two dnaA sites

were separated relative to each other by rotating the sites one half turn

around the DNA helix. Fourth, the dnaA sites were duplicated and placed in a

number of orientations and juxtapositions relative to each pair of dnaA sites

and relative to the repA sites. Modifications one through three have had

little effect on initiation of DNA replication in vitro. Modification four

is currently being tested. In addition, the effect of the deletions on the

ability of the origin to function in vivo is currently being tested.

This work should precisely define the limits of the PI origin, provide a framework to compare the DNA structural and functional requirements for

initiation of DNA replication, and indicate avenues for further research.

6
This work was presented at the Gordon Conference on Nucleic Acids in June,

1988 and the Cold Spring Harbor Meeting, "Molecular Biology of Bacteria and

Their Phages," in August, 1988.

Protein Structure and Function in Regulation of Gene Expression

K. McKenney, M. Kantorow (George Washington University)

This project is aimed at understanding the relationship between

structure and function of the cyclic AMP receptor protein, crp, in the

regulation of gene expression. It binds to specific DNA sequences in the E.

coli chromosome to effect the transcriptional activation of a number of genes

involved in sugar utilization. It does not bind specifically to DNA unless

it first binds cyclic AMP (cAMP) . Thus, crp represents a protein with a

"molecular switch" that can be turned on by the addition of cAMP to the pure

protein in vitro or to the whole cell in vivo. The structural details of the

"molecular switch" mechanism are being explored through the study of crp

proteins whose amino acid sequences are altered either by natural mutations

or by site directed mutagenesis. A remarkably efficient gene fusion method

has been developed to facilitate the construction of a large number of

modified crps. The method, which will be of general utility for efficient

protein engineering, relies on the precise fusion of the modified crp gene to

the lacZ ("blue") gene. The lacZ component of the fusion protein will cleave

beta-chloro- indole -galactose to produce a blue plaque. This indicator allows

one to easily distinguish the site-directed mutant crps from parental crps

based on a change in plaque color on a lawn of bacteria growing on a Petri

dish.

In addition to the demonstration of the general utility of the lacZ

fusion method to identify and purify site-directed codon substitutions in

gene coding sequences , we have begun to explore a new method that has the

potential to bypass the requirement of synthetic oligonucleotides for protein

engineering. This method uses DNA polymerase to misincorporate bases

randomly throughout the crp gene and to subsequently plate the recombinants

on indicator plates to identify those mutants that have incorporated stop

codons in the crp gene. These are purified and characterized by DNA

sequencing. Any one of these mutants can be used as a substrate to revert a

specific stop codon to a readthrough codon (and hence an amino acid

substitution in the crp protein) by using the misincorporation reaction and

isolating the desired substitution as a blue plaque on the indicator plates.

Future plans include the purification of large quantities of the crp

protein so that crystallization can be attempted in the absence of cAMP. The

structure of crp with bound cAMP is already known, and a determination of the

structure without cAMP by x-ray crystallography would yield important

information on the structural changes that constitute the "molecular switch."

We also intend to study the thermodynamics of folding/unfolding of the

natural and modified crps in order to correlate observed variations in DNA

binding specificity with the structural changes and thermodynamic stability

of the proteins.

7
Catalytic Domain Analysis of Adenylate Cyclase

P. Reddy

The determination of the catalytic domain of an enzyme is the first step

in understanding the enzyme's mechanism of action and specificity at the

molecular level. In this project, the methods of molecular biology are used

to elucidate the precise protein coding sequence required for catalytic

activity of the adenylate cyclase (cya) enzyme. The protein has 95 000

molecular mass and has both a catalytic and a regulatory domain. It

catalyzes the synthesis of cyclic AMP from ATP. The gene has been cloned and

sequenced. We have recently developed an efficient system to hyperexpress

this lethal gene product in cells and purified the protein to near

homogeneity.

We have designed and made a three -membered family of synthetic

oligonucleotides that facilitate the precise definition of the minimal

catalytic domain of cya in this case and any gene in general. The synthetic

oligonucleotides have three important components: (1) stop codons (TAA) are

in all three reading frames; (2) the recognition sequence CATATG for the

restriction endonuclease Ndel precedes and follows the stop codons; and (3)

the sequence is self complementary (when denatured and renatured, the s ingle - stranded DNA will form a duplex with blunt ends and hence be clonable) . The

members of the family differ in the number of bases between the Ndel site and

the end of the oligo, either 0, 1, or 2 bases. The gene coding for adenylate

cyclase is opened at various sites, the appropriate synthetic oligonucleotide

is inserted, and the modified genes are characterized for their ability to

produce a functional adenylate cyclase. The inserted stop codon causes

premature translation termination and results in a "carboxy end" deletion in

the protein. Sites in the adenylate cyclase gene were chosen that result in

production of six "carboxy-deleted" proteins of 10, 20, 40, 50, 60, and 80

thousand molecular mass. Protein molecules of 40 k through full length have

enzymatic activity. We can also study "amino-deleted" domains of cya by

using the Ndel site introduced by the synthetic DNA and deleting the cya gene

coding sequences between the natural cya ATG initiation codon (which is

preceded by a Ndel site) and the point of insertion of the synthetic DNA.

We are now in the process of constructing the amino-deleted set of

molecules which will be studied for activity. Then, we will combine the

minimal carboxy end with the minimal amino end and generate this protein in

large quantities for biochemical and physical studies.

Thermodynamics of Biochemical Processes

R.N. Goldberg, Y.B. Tewari, K. Fazio, J.C. Ahluwalia (Indian Institute of

Technology)

Thermodynamic investigations of the hydrolysis of the disaccharides

maltose, isomaltose, gentiobiose, and cellobiose have been completed. These

studies involved the use of a high-pressure liquid chromatograph having a

pulsed-amperometric detector for the determination of extents of reaction and

8
equilibrium constants. Microcalorimetry was used for the determination of

enthalpy changes as a function of temperature. The derived thermodynamic

parameters allow one to predict the thermodynamic behavior of these chemical

processes as a function of temperature and have also yielded information on

the relationship of the thermodynamic parameters to the structural features

involved in these disaccharides

A review of ten major industrial processes utilizing enzyme -catalyzed

reactions has been completed. In it, the thermodynamic data for these

processes are summarized. This information, much of it determined in this

laboratory, can be used to calculate the extents of reaction and the energy

requirements for these processes as functions of operational variables such

as pH, ionic strength, metal -ion concentrations, and temperature.

A data base on the thermodynamics of enzyme -catalyzed reactions has been

initiated by searching the literature, and hard copies of those papers

containing the relevant equilibrium and calorimetric data have been obtained.

Approximately 1500 references have been located to date.

R.N. Goldberg and Y.B. Tewari organized a symposium on "Fundamental

Biochemical Processes" as a part of the 43rd Annual Calorimetry Conference.

Calibration Data for Differential Scanning Calorimetry

F.P. Schwarz

Thermodynamic data for the calibration of differential scanning

calorimeters have been extended up to 75° C by measurements of the unfolding

transition of lysozyme in HC1- glycine buffer. The data cover the temperature

range from 52 °C at pH 2 to 75 °C at pH 4. This overlaps and extends the data

previously generated for ribonuclease-a in HCl-glycine buffer, which covers

the range from 37°C at pH 2 to 64°C at pH 4. The calorimetric and van't Hoff

enthalpies of lysozyme increase linearly with transition temperature:

AH (van' t Hoff in kJ/mol) = (432.7±1.7) + (5 . 81±0 . 24) (Tm - 337.2)

AH(calorimetric in kJ/mol) = (434.7±4.1) + (6 . 39±0 . 60) (Tm - 337.2)

where Tm is the transition temperature in kelvins. The results are

independent of the commercial source of lysozyme (provided that the solutions

are dialyzed), lysozyme concentration, buffer concentration, and scan rate.

Work is in progress to extend the thermodynamic calibration data up to

80-85°C using the unfolding transition of trypsin inhibitor in HCl-glycine

buffer

9
Differential Scanning Calorimetry in Biothermodynamics

F.P. Schwarz, D. Atha (NIST Center for Analytical Chemistry), K. Ingham

(American Red Cross)

Differential scanning calorimetry (DSC) measurements have been performed

on solutions of fibronectin, a plasma protein responsible for clotting in the

blood, in the absence and presence of heparin, an anticlotting agent. This

system represents an interesting multidomain protein folding problem with

effects due to inhibitor binding. Fibronectin is a glycoprotein composed of

two nearly identical polypeptide chains joined together near the C- terminus

by a pair of sulfide bonds. Each chain consists of five domains. We have

confirmed the presence of two transition peaks, at 62° C and 70° C, in the

denaturation of fibronectin, which were recently reported by Niedzwiadek et

al . in Biochemistry 2_7, 7116 (1988). The high temperature transition peak is

only about 25% of the total peak area and had not been identified prior to

this recent work. Analysis of our DSC data in terms of cooperativity and

specific enthalpy indicates that the first peak corresponds to the partial

unfolding of all ten fibronectin domains, while the second peak is due to the

additional unfolding of five of the domains.

The polysaccahride heparin can bind to several sites in the fibronectin.

The binding of this inhibitor can change the thermodynamics of unfolding

depending on the molecular details of the interactions. The DSC analysis of

fibronectin with heparin bound shows that the cooperativity in the first

transition is reduced from ten to five, while the cooperativity in the second

transition remains the same. Thus it appears that the heparin is binding

tightly to several domains of the fibronectin and causing them to unfold as

one domain. In addition, the first transition temperature increases by^l°C,

corresponding to an average binding constant of at least 1.5 X 10^ mol at

62°C

Preliminary experiments have been performed with a shorter segment of

heparin which binds to fewer sites on fibronectin, with a correspondingly

smaller change in the reduction of cooperativity in the first transition. We

are presently doing DSC scans of fragments of fibronectin in the absence and

presence of heparin to obtain more insight into the binding mechanism.

Biological Macromolecule Crystallization Data Base

G. Gilliland, D. Bickham (NIST Office of Standard Reference Data)

A crystallization data base, the Biological Macromolecule

Crystallization Data base, has been completed and is now ready for

distribution. This data base, which is accessed through a PC-based computer

program, is intended to provide the examples and physical data required for

the formulation of effective crystallization strategies for macromolecules.

The data base has been compiled from the scientific literature and

contains crystal data and crystallization conditions for more than 1000

crystal forms of over 600 biological macromolecules. Data for proteins,

10
proteinrprotein complexes, nucleic acids, nucleic-acid:nucleic-acid

complexes, protein:nucleic-acid complexes, and viruses have been included.

The general information catalogued for each macromolecule includes the

macromolecule name(s) , the molecular mass, the subunit composition, the

presence of prosthetic group(s), and the source of the macromolecule. The

crystal data include the unit cell parameters, space group, crystal density,

crystal habit and size, and diffraction limit and lifetime. The

crystallization data consist of the crystallization method, chemical

additions to the crystal growth medium, macromolecule concentration,

temperature, pH, and growth time. A result of the compilation of the

crystallization data was the development of a general strategy for the

crystallization of soluble proteins. The stategy employs vapor diffusion

experiments with the most frequently used crystallization agents and

microdialysis against low ionic strength to maximize the possibility of

obtaining crystals. This work has been published in the Journal of Crystal

Growth.

The Three-Dimensional Structure of Recombinant Bovine Chymosin

G. Gilliland, E. Winborne (University of Maryland), J. Nachman (National

Cancer Institute) , A. Wlodawer (National Cancer Institute)

A high-resolution structure for a cloned version of the enzyme chymosin

has been determined by x-ray crystallography. Chymosin is the principal

enzyme involved in cheese production and was originally prepared from the

stomach linings of calves. It is one of the oldest commercial enzymes. The

chymosin used in the crystallographic studies was commercially cloned and

expressed in escherichia coli . The structure has been determined with a

resolution of approximately 0.23 nm and a crystallographic R factor of 0.19.

Chymosin belongs to a class of enzymes called acid proteases and has an

active site structure which is very similar to other proteins in that class.

Now that the structure has been determined, work is underway to design

inhibitors and to model the catalyzed proteolysis in order to learn more

about the mechanism and specificity of this important class of enzymes.

Chymosin is similar to the enzyme renin, which is found in the blood and

plays a role in regulating blood pressure. Thus, an accurate structure for

chymosin may have use in drug design studies.

Ab Initio Reaction Field Method Development

W. Stevens, D. Garmer, M. Krauss (NIST Center for Atomic, Molecular, and

Optical Physics), H. Basch (Bar Ilan University, Israel)

Final tests have been made of the first version of an ab initio reaction

field computer program which will be used for quantum mechanical studies of

complex systems. The reaction field approach divides a large molecular

complex into an "active" region, which is to be characterized quantum

mechanically, and a "spectator" region that may be modeled as an assembly of

polarizable molecular fragments that are not directly involved in the

11
chemistry. How the boundary between the active and spectator regions is

chosen depends on the properties or chemistry one wishes to study. We are

currently choosing the boundary so that the interactions between fragments in

the two regions is of the nonbonded type. The Hamiltonian of the active

region consists of the normal Hamiltonian for the active electrons and

nuclei, plus an effective Hamiltonian that describes the electrostatic and

exchange repulsion interactions between the active and spectator regions, and

a perturbation Hamiltonian that accounts for the polarization of the

spectator fragments. It is the polarization term that provides the

"reaction" of the spectator region to molecular structure changes that occur

in the active region.

Tremendous saving of computer time is possible through the reaction

field approach, since only the electrons in the active region need to be

considered explicitly and the effective Hamiltonian between the active and

spectator regions involves only one-electron integrals. Thus, molecular

systems too complex for the standard ab initio methods can now be studied. We

have developed methods for obtaining the parameters for the effective

Hamiltonians from ab initio calculations on prototypical molecular fragments.

These parameters appear to be transferrable at the functional group level, so

very complex spectator regions can be modeled by a collection of

predetermined "fragment potentials."

We have successfully tested this reaction field approach on a variety of

hydrogen-bonded complexes consisting of water, formamide , and glycine. We

find that the interaction energy surface for any pair of molecules can be

reproduced to within 10-20% when either of the molecules is replaced by the

reaction field Hamiltonian. The largest absolute errors are due to the

representation of the electrostatic interaction, which is truncated at

octupoles for each expansion center. We have also treated complexes of

formamide hydrogen-bonded to two water molecules and find the cooperativity

in the hydrogen bonding is predicted very accurately when both water

molecules are replaced by reaction field Hamiltonians.

The next steps in the reaction field development include testing the

transferability of the parameters in larger molecules such as proteins,

testing the validity of the distributed dipole polarizability approximation

in interactions of charged species (particularly anions) , the addition of

dispersion terms to the perturbation Hamiltonian, and the development of

integral gradients that are needed for geometry optimization. Long range

goals include the development of molecular mechanical methods for modifying

the geometric structure in the spectator region in response to changes in the

active region. Applications of the reaction field program, in the coming

year, will include models of the active site of carbonic anhydrase with

different metal substitutions and a model of the active site in aspartyl

proteases to determine the electrostatic potential and the relative

energetics of proton transfers.

12
Cluster Model Analysis of Metal Binding Selectivity

W. Stevens, M. Krauss (NIST Center for Atomic, Molecular, and Optical

Physics)

The binding of metal cations to proteins is important in both protein

function and protein stability. We have used ab initio molecular orbital

calculations to develop a model of cation binding energetics and selectivity.

We have determined the binding energies of metal cations to octahedral

clusters of water, formamide , and formate ligands, and have used these data

to analyze Ca+^ binding sites in proteins. The intrinsic energetics of the

first coordination shells provide a basis for evaluating the conformational

behavior and the selectivity of cation binding. The total enthalpies of

solvation and binding were modeled by estimating the Born polarization energy

of the bulk relative to the first shell model cluster. Cluster reaction

enthalpies were calculated for transferring Mg , Ca , and Na -1- cations from

a water cluster to the protein model cluster. Cluster size, determined by

the distance between the cation and the closest ligand atoms, was found to

strongly affect the binding selectivity between cations of the same and

different charges. The selectivity is a function of both steric and

electrostatic interactions. The model data have been applied to an analysis

of the binding sites in the protein subtilisin BPN.

Thermodynamics of Iron Compounds

M.W. Chase, D. Garvin, J.L. Haas, Jr. (U.S. Geological Survey)

Recommended values for the thermodynamic properties of compounds of iron

are being prepared for the CODATA Task Group on Thermodynamic Tables, which

is preparing a book and data base that will include the thermochemistry and

thermal functions for some 40 compounds and analyses of 7 high temperature

systems. This effort will combine NIST work with evaluations made in Moscow,

Stockholm, Grenoble and Harwell.

Iron. The thermal and volumetric properties of iron have been

reassessed over the temperature range 250 K to 2400 K, and from 0.1 to 20

MPa. An accurate representation of the properties has been obtained over

these ranges, which cover all metallurgical, but not all geochemical

applications. Above 20 MPa and 2400 K, there are insufficient data to

establish the melting line, and the few that exist may be inconsistent with

the rest of the set.

Magnetite. The heat capacity of Fe 304 , 0 to 325 K, and its entropy at

298.15 K have been reevaluated. The new recommended values for Fe 3

C>4 at

298.15 K are S = 148.3±2.4 J/(mol*K) , Cp =152.8±3.0 J/(mol*K) and H-H(0 K) = 25.152±0.47 kJ/mol. The values are based on low temperature Cp measurements

in four laboratories on five distinct samples of synthetic Fe 304 . Three of

the samples are single crystals; two are polycrystalline. Data for the first

three have been published only as graphs, and were obtained from the authors.

The considerable differences among the results, e.g., S(298.15 K) ranging

from 146.1 to 152 J/(mol»K) , are attributed to the samples and not to the

13
measurement process. Previously, S(298.15 K) had been taken as 146.1 ±0.15

J/(mol»K), based on precise measurements on only one of the samples

considered here.

The reason for undertaking this study was another discrepancy. An

optimization of the Fe/0 system, considering both heat capacity and high

temperature equilibrium data, predicts S(Fe 304 ) at 298.15 K = 145.4±0.3

J/(mol»K). Since our study indicates that S is likely to be higher than the

previously accepted value, not lower, attention has shifted to the

remeasurement of Cp from room temperature to 1000 K. (Above 900 K there is a

4 J/(mol«K) difference between two sets of measurements). The experimental

studies are being made at the U.S.G.S. and possibly will be made at the

University of Michigan.

The Fe/0 system (solid) . The high temperature equilibrium data on

reactions among Fe 203 (hematite), Fe 3C>4 (magnetite) and Fe^_y)0 (wustite)

and iron, and the Cp and H-H(298.15 K) data have been combined in a thermodynamic optimization of the entire system. A refinement of earlier

models has been used. By elimination of data taken using methods now known

to have systematic flaws and those sets showing major mismatches, the

agreement between data and calculation has been improved by a factor of two.

The results of this optimization have been recast into the "sublattice model"

formulation that is gaining favor in thermodynamic modeling of high

temperature phase diagrams. This recasting will be used in the modeling of

the liquid Fe/0 system at the Royal Institute of Technology, Stockholm, and

later, for ternary systems.

JANAF Thermochemical Tables

M.W. Chase, S. Abramowitz

There are two projects in progress which will result in the generation

of new and revised entries to the JANAF Thermochemical Tables collection.

These activities are sponsored by AFOSR and the JANNAF Combustion

Subcommittee. The first project deals with the study of species involving

the alkaline earth metals.

The latter study is focused on the characterization of the species

involved in combustion processes and is being done in conjunction with the

Chemical Kinetics Division. This joint effort is designed to provide

thermodynamic and kinetic information on the combustion processes resulting

from the burning of propellants. The chemical species currently under study

include many of the nitrogen oxides.

With an increasing emphasis on the development of a comprehensive data

base on the elements, bibliographic and data files have been created and are

being maintained. The aim is to provide a complete annotated bibliographic

file which summarizes the thermodynamic information available on many

elements. As the bibliographic file is updated, a corresponding data file,

containing the experimental data, is updated. These data are available then

for immediate comparison with the previously existing data and reanalysis.

14
The collection and analysis of temperature dependent data require not

only a series of calculational computer codes, but also a technique for

displaying the information. During the past year, a graphics routine was

developed and directed specifically to the display of heat capacity,

enthalpy, and vapor pressure data. Based on a commercially available

software package, this routine easily permits the display of the experimental

results and the evaluated results in a user specified temperature range and a

user specified value range. The graph can be displayed on the terminal

screen, in standard letter size hard copy, or in enlarged sizes up to 75 cm

by 90 cm.

Chemical Abstracts

M.W. Chase, D. Bickham (NIST Office of Standard Reference Data)

During the past year, two of the Division's data bases were installed on

the CAS/STN network. The JANAF Thermochemical Tables and the NIST Tables of

Chemical Thermodynamic Properties are both available on-line through the

Chemical Abstracts CAS/STN network system.

Thermodynamic Properties of Aqueous Solutions of Strong Electrolytes

D.B. Neumann, D.G. Archer, P. Wang (Guest Researcher), T.L. Jobe, Jr.

The Electrolyte Data Center (ELDC) will provide a data base of evaluated

equations for thermodynamic properties of aqueous solutions of strong

electrolytes. A prototype version was implemented on a mini - computer . The

package was transferred to personal computers. Approximately 350 salts at

25 °C are now covered by the package. The temperature dependence of the

thermodynamic properties is to be added. This will be accomplished, for a

large fraction of the salts, using Pitzer's values of the temperature derivatives. More accurate temperature dependencies are being added for the few

salts (less than 20) for which such data are available.

Aqueous Thermodynamic Data Base

P. Wang (Guest Researcher), D.B. Neumann, D. Garvin

The development of the Aqueous Thermodynamics Data Base is a cooperative

project with the Institute for Chemical Metallurgy (ICM) of Beijing, China.

During this year, the package was improved to incorporate the data base of

thermodynamic properties from the M NBS Tables of Chemical Thermodynamic

Properties." The package was converted in limited form from a mini-computer

to personal computers. Extended graphics capabilities were incorporated into

the PC version to permit the display of E-pH (Pourbaix) diagrams.

Arrangements were made through the NIST/OSRD for the continuation of this

cooperative project with ICM.

15
The Corrosion Data Center at NIST is sponsored in part by the National

Association for Corrosion Engineers (NACE) . This group has also had a

project to develop a personal computer package for E-pH (Pourbaix) diagrams.

Under the aegis of the NIST/OSRD, an extensive test and comparison of the two

packages were undertaken. A clear need was demonstrated for a single

consistent and compatible data base of thermodynamic properties for both

packages

Dielectric Constant of Water

P. Wang (Guest Researcher), M.L. Jappas (Guest Researcher), D. Garvin,

J.V.H. Sengers (Thermophysics Division)

A comprehensive program was undertaken to re -fit (provide a temperature - density dependent equation) the dielectric constant of pure water. This

project arose as a result of new measurements of the dielectric constant of

water. In addition, in 1974, the International Association for the

Properties of Steam approved a release entitled "International Representation

of the Static Dielectric Constant of Water Substance." It was recently found

that the low temperature and pressure region of this representation was not

sufficiently accurate to represent the derivatives of the dielectric constant

with respect to temperature and pressure. Consequently it did not provide

adequate values for the Debye -Huckel limiting law, i.e. the limiting behavior

of thermodynamic properties of dilute aqueous solutions as a function of

ionic strength. The re -fitting, which is near completion, has caused a

reanalysis of the internationally accepted equation-of-state for pure water.

Publication of the results of this work is expected in early FY89.

NIST Tables of Chemical Thermodynamic Properties Data Base

D.B. Neumann, P. Wang (Guest Researcher)

A search and retrieval package for the "NIST Tables of Chemical

Thermodynamic Properties. Selected Values for Inorganic and C ]_ and C 2

Organic Substance in SI Units" has been prepared for personal computers. The

package is under test and a paper describing the package has been submitted

to the Journal of Chemical Information and Computer Sciences. On completion

in the early part of FY89, the package will be made available by the

NIST/OSRD.

Estimation of Thermodynamic Properties of Organic Compounds

E.S. Domalski, E.D. Hearing

An estimation method for the calculation of enthalpies of formation,

heat capacities, and entropies, which consists of a group contribution value

approach (developed by S.W. Benson and co-workers for gas phase organic

compounds) has been extended to the liquid and solid phases for hydrocarbon

compounds at 298.15 K. For consistency, the gas phase group values have been

16
re-examined as well. A comparison is provided between experimental and

calculated values for over 1300 hydrocarbon compounds and will appear in J

Phys . Chem. Ref. Data, No. 4, 1988.

Group values for organic compounds containing the elements carbon,

hydrogen, and oxygen (CHO) were developed. Group values for organic

compounds containing the elements carbon, hydrogen, and nitrogen (CHN) and

carbon, hydrogen, nitrogen, and oxygen (CHNO) will be developed.

An estimation algorithm has been developed to calculate the enthalpy of

formation, heat capacity, entropy, entropy of formation, Gibbs energy of

formation, and natural logarithm of the equilibrium constant for the

formation reaction at 298.15 K for hydrocarbon compounds and CHO compounds.

The algorithm and data bases on 1300 hydrocarbons and 1000 CHO compounds are

on diskettes. The programs are being made user friendly. Technical notes

describing the estimation algorithm, data bases, and estimation procedures

will be provided as a package from NIST/OSRD in the near future.

An update of the J. Phys. Chem. Ref. Data Supplement published in 1984

has been prepared and entitled "Heat Capacities and Entropies of Organic

Compounds in the Condensed Phase." The update, which includes about 1000

compounds, covers both reported data which were not included in the 1984

JPCRD publication (1881-1982) and data which appeared in the literature since

1982 (1982-1987).

5. PUBLICATIONS

Ammon, H.L., Weber, I.T., Wlodawer, A., Harrison, R.W.

,

Gilliland, G.L.,

Murphy, K.C., Sjolin, L. and Roberts, J., Preliminary crystal structure

of acinetobacter glutaminasifians glutaminase - asparaginase , J. Biol.

Chem., Vol . 263, pp . 150-156 (1988).

Basch, H. , Krauss , M. and Stevens, W.J., Cation binding effect of imidazole

tautomerism, Int. J. Quantum Chem., Vol. 31, pp . 405-415 (1987).

Buckley, T.J. and Domalski, E.S., Evaluation of data on higher heating values

and elemental analysis for refuse-derived-fuels, Proc . of the 13th

National Waste Processing Conference and Exhibit, Phila., PA (May 1-4,

1988), ASME, NY, pp . 77-84 (1988).

Chase, M.W.

,

Thermodynamic properties of the alkaline earth metal hydroxides

(MOH) , I. Literature citations, NBS Tech. Note 1243, (Dec. 1987).

Churney, K.L., Chlorine mass balance in the combustion of solid waste, Proc.

of the 13th National Waste Processing Conference and Exhibit, Phila., PA

(May 1-4, 1988), ASME, NY, pp . 47-56 (1988).

Colbert, J.C., Domalski, E.S., Coxon, B. and VanderHart, D.L., Enthalpy of

combustion of hexaglycine, J. Chem. Thermodyn. , Vol. 19, pp . 433-441

(1987) .

17
Ditmars, D., Drop calorimetry above 300 K, Chapter 6 in book Specific Heat of

Solids, Vol. 1-2 CINDAS Data Series on Material Properties:

Hemisphere Publishing Corp . , New York, NY (1988).

Domalski, E.S., Jobe, T.L., Jr. and Milne, T.A., Thermodynamic data for

biomass materials and waste components: Editors; ASME, New York, NY

(1987) .

Domalski, E.S., Estimation of thermodynamic properties of organic compounds

in the gas, liquid, and solid phases at 298.15 K, Proc . of the Beilstein

Workshop on the Estimation of Physical Data for Organic Compounds,

Springer-Verlag , Frankfurt, Germany (1988).

Fraser, G.T., Suenram, R.D., Lovas , F.J. and Stevens, W.J., Microwave

spectrum of the CH3 OH-NH3 complex, J. Chem. Phys . , Vol. 125, pp . 31-43

(1988) .

Garvin, D. , CODATA thermodynamic tables: selections for some compounds of

calcium and related mixtures - a prototype set & tables, D. Garvin,

V. Parker and H.J. White, Jr., eds .

,

Hemisphere Publishing Corp.,

New York, NY (1987)

Garvin, D., Parker, V.B. and Nuttall, R.L., Thermochemical properties at 0

and 298.15 K, in CODATA Thermodynamic Tables: Selections for Some

Compounds of Calcium and Related Mixtures - A Prototype Set & Tables, D.

Garvin, V. Parker and H.J. White, Jr., eds., Hemisphere Publishing

Corp., New York, NY (1987).

Gilliland, G.L., Howard, A.J., Winborne , E.L., Poulos, T.L., Stewart, D.B.

and Durham, D.R.

,

Crystallization and preliminary X-ray diffraction

studies of subtilisin GX from bacillus sp. 6644, J. Biol. Chem., Vol.

262, pp. 4280-4283 (1987).

Gilliland, G.L., Winborne, E.L., Masui , Y. and Hirai, Y. , A cys tallographic

study of recombinant human interleukin 1/3, J. Biol. Chem., Vol. 262, pp

12323-12324 (1987).

Gilliland, G.L., A biological macromolecule crystallization database: a basis for a crystallization strategy, J. Cryst. Growth, Vol. 90,

pp. 51-59 (1988).

Gurvich, L.V.

,

Yungman, V.S., Chase, M.W. and Bergman, G.A., Thermodynamic

properties of individual substances, in CODATA Thermodynamic Tables:

Selections for Some Compounds of Calcium and Related Mixtures - A

Prototype Set & Tables, D. Garvin, V. Parker and H.J. White, Jr., eds.

Hemisphere Publishing Corp., New York, NY (1987).

Harman, J., Peterkofsky, A. and McKenney, K. , Arginine substituted for

leucine at position 195 produces a cylic AMP independent form of the

escherichia coli cylic AMP receptor protein, J. Biol. Chem., Vol. 263,

No. 17, pp. 8072-8077 (1988).

18
Harrison, R.W.

,

Gilliland, G.L., Weber, I.T., Wlodawer, A. and Ammon, H.

,

Crystal structures of bacterial glutaminase-asparaginases , Protein

Structure and Design 2, UCLA Symposia on Molecular and Cellular

Biology, New Series, Vol. 69, pp . 83-92 (1987).

Howard, A.J., Gilliland, G.L., Finzel, B.C., Poulos , T.L., Ohlendorf, D.H.

and Salemme, F.R.

,

Use of an imaging proportional counter in

macromolecular crystallography, J. Appl. Crystallog. , Vol. 20, pp

383-387 (1987).

Jackson, C.R. and Chase, M.W.

,

Halides, hydrides, and deuterides of cobalt,

iron and nickel, I. Literature citation, NBS Tech. Note 1244 (Dec.

1987) .

Jasien, P.G. and Stevens, W.J., Theoretical calculations of diatomic metal

oxides. CrO and CrO4", Chem. Phys . Lett., Vol. 147, pp . 72-78

(1988) .

Kirklin, D.R. and Domalski, E.S., Enthalpy of combustion of

triphenylphosphine and triphenylphosphine oxide, J. Chem. Thermodyn.

,

Vol. 20, pp. 743-754 (1988).

Kirklin, D.R., Enthalpies of combustion of organic phosphorus compounds,

Proc . of the 15th Annual National Conference of the National

Organization for the Professional Advancement of Black Chemists and

Chemical Engineers (NOBCChE) , Phil., PA (Apr. 4-8, 1988).

Kirklin, D.R. and Domalski, E.S., The impact of ion chromatography on the

enthalpies of formation of organic phosphorus compounds, Proc. of

the 1987 U.S. Army Chemical Research, Development and Engineering

Center Scientific Conference on Chemical Defense Research, Aberdeen

Proving Ground, MD, Aberdeen, MD, (Nov. 17-20, 1987) pp . 743-754.

Lam, A.C. and Archer, D.G., Enthalpies of dilution of dodecyl- and

tetradecyl- trimethylammonium bromides in aqueous sodium bromide at

elevated temperatures, J. Chem. Thermodyn., Vol. 20, pp . 825-841

(1988) .

Schwarz, F.P. and Kirchhoff, W.H.

,

Biological thermodynamic data for the

calibration of differential scanning calorimeters: heat capacity

data on the unfolding transition of ribonuclease-a in solution,

Thermochimia Acta, Vol. 128, p. 267 (1988).

Smith-Magowan, D., Garvin, D., Parker, V.B., Nuttall, R.L. and Staples, B.R.,

The aqueous system CaCl 2 H2 O, in CODATA Thermodynamic Tables: Selections

for Some Compounds of Calcium and Related Mixtures - A Prototype Set &

Tables, D. Garvin, V. Parker and H.J. White, Jr., eds .

,

Hemisphere

Publishing Corp .

,

New York, NY (1987).

Stevens, W.J. and Fink, W.H.

,

Frozen fragment reduced variational space

analysis of hydrogen bonding interactions. Application to the

water dimer, Chem. Phys. Lett., Vol. 139, pp . 15-22 (1987).

19
Tewari, Y.B., Steckler, D.K. and Goldberg, R.N. , Thermodynamics of

isomerization reactions involving sugar phosphates, J. Biol. Chem. , Vol.

263, pp. 3664-3669 (1988).

Tewari, Y.B., Steckler, D.K. , Goldberg, R.N and Gitomer, W.L., Thermodynamics

of hydrolysis of sugar phosphates, J. Biol. Chem., Vol. 263, pp . 3670-

3675 (1988).

Tewari, Y.B. and Goldberg, R.N. , Thermodynamics of the conversion of

penicillin G to 6-aminopenicillanic Acid, Biophys. Chem., Vol. 29,

p. 245 (1988).

Weber, I.T., Gilliland, G.L., Harman, J. and Peterkofsky, A., Structure of a

cyclic AMP- independent mutant of catabolite gene activator protein, J.

Biol. Chem., Vol. 262, pp . 5630-5636 (1987).

Weber, I.T., Vaney, M-C., Gilliland, G.L., Harman, J.G. and Peterofsky, A.,

Effect of a cAMP- independent mutation on crystal structure of catabolite

gene activator protein, Protein Structure and Design 2, UCLA Symposia on

Molecular and Cellular Biology, New Series, Vol. 69, pp . 65-74 (1987).

Wickner, S. and McKenney, K. , Minimal DNA sequence required for the

initiation of bacteriophage lambda plasmid replication, J. Biol.

Chem., Vol. 262, No. 27, pp . 13163-13167 (1987).

Wlodawer, A., Nachman, J., Gilliland, G.L., Gallagher, W. and Woodward, C.,

Structure of form III crystals of bovine pancreatic trypsin inhibitor,

J. Mol. Biol., Vol. 198, pp . 469-480 (1987).

Wlodawer, A., Svensson, L.A.

,

Sjolin, L. and Gilliland, G.L., Structure of

phosphate -free ribonuclease-a refined at 1.26x, Biochemistry, Vol. 27,

pp. 2705-2717 (1988).

Wlodawer, A., Svensson, L.A.

,

Sjolin. L. and Gilliland, G.L., Ribonuclease-a:

conserved aspects of the three-dimensional structure based on a

comparison of high resolution structures, Protein Structure and Design

2, UCLA Symposia on Molecular and Cellular Biology, New Series, Vol. 69,

p. 118 (1987).

Wright, C.F., Hamer, D. and McKenney, K. , Autoregulation of the yeast copper

metallothionein gene depends on metal binding, J. Biol. Chem., Vol. 263,

No. 3, pp. 1570-1574 (1988).

Wright, C.F., McKenney, K. , Hamer, D., Byrd, J. and Winge, D.R., Structural

and functional studies of the amino- terminal cleavage of yeast

metallothionein, J. Biol. Chem., Vol. 262, No. 27, pp . 12912-12919

(1987)

20
In Progress:

Archer, D.G., Comment: On the monodisperse-micelle , mass-action model for

aqueous ionic - surfactant solutions, J. Phys . Chem. (submitted).

Archer, D.G., The second virial coefficients of aqueous alcohols of elevated

temperatures; A calorimetric study, J. Phys. Chem. (submitted).

Colbert, J.C., Enthalpy of combustion of hexaglycine, J. Chem. Thermodyn.

(submitted)

Domalski, E.S., Combustion calorimeters, Proc . of the Fourth Polish

Conference on Calorimetry and Thermal Analysis, Zakopane, Poland (1988).

Goldberg, R.N. and Tewari, Y.B., Thermodynamic and transport properties of

carbohydrates and their monophosphates: the pentoses and hexoses, J.

Phys. Chem. Ref. Data (in press).

Kirklin, D.R. and Domalski, E.S., Enthalpies of combustion of nebularine,

adenosine, and guanosine, J. Chem. Thermodyn. (submitted).

Kirklin, D.R. and Domalski, E.S., Enthalpy of combustion of

triphenylphosphate , J. Chem. Thermodyn. (submitted).

Krauss, M. and Stevens. W.J., A theoretical model of metal binding sites in

proteins, Proc. of the Vlth Oholo Conference (in press).

Luo, J., Ammon, H.L. and Gilliland, G.L., PLOTMD - An interactive program to

modify molecular plots on a graphics terminal, J. Appl. Crystallog.

(submitted)

Neumann, D.B. and Wang, P., The electrolyte data centers at the National

Bureau of Standards, USA and cooperative research with the

Institute of Chemical Metallurgy in Beijing, China, Proc. of the

Symposium on Chemistry on High Temp Aqueous Solutions, Picone, Utah

(Aug. 25-27, 1987) (in press).

Neumann, D.B. and Wang, P., Electrolyte data centers at the National Bureau

of Standards, USA and the Institute of Chemical Metallurgy in Beijing,

China, Proc. of the International Conference on Thermodynamics of

Aqueous Systems with Industrial Applications, Warrenton, Virginia (May

10-14, 1987) (in press).

Neumann, D.B. and Wang, P., A database and retrieval system for the NBS

tables of chemical thermodynamic properties, J. Chem. Info. Comput.

Sci . ( in press )

Pantoliano, M.W.

,

Whitlow, M. , Wood, J.F., Rollence, M.L., Finzel, B.C.,

Gilliland, G.L., Poulos , T.L. and Bryan, P.N., The engineering of

binding affinity at metal ion binding sites for the stabilization

of proteins: subtilisin a test case, J. Biol. Chem. (submitted).

21
Reddy, P. , Peterfkofsy, A. and McKenney, K. , Hyperexpression and purification

of escherichia coli adenylate cyclase, J. Biol. Chem. (submitted).

Schwarz, F.P., A differential scanning calorimetry study of the interaction

of inhibitors with ribonuclease-a at the denaturation temperature,

Biochemistry (in press).

Schwarz, F.P., Self -association of alpha chymotrypsin in acid solutions,

Biochemistry (submitted)

Schwarz, F.P., Biological thermodynamic data for the calibration of

differential scanning calorimeters: Heat capacity data on the unfolding

transition of lysozyme in solution, Thermochimica Acta (submitted)

Schwarz, F.P., Steer, C.J. and Kirchhoff, W.H.

,

A differential scanning

calorimetric study of brain clathrin, Biochemistry (in press).

Simonson, J.M., Holmes, H.F., Busey, R.H.

,

Mesmer, R.E., Archer, R.G. and

Wood, R.H.

,

Modeling of the thermodynamics of electrolyte solutions to

high temperatures including ion association. Application to

hydrochloric acid, J. Phys . Chem. (submitted).

Steele, W.V. , Archer, D.G., Chirico, R.D., Collier, W.B., Gammon, B.E.,

Hossenlopp, I. A., Nguyen, A. and Smith, N.K., The thermodynamic

properties of quinoline and isoquinoline, J. Chem. Thermodyn.

(submitted)

Tewari, Y.B., Thermodynamics of industrially important enzyme catalyzed

reactions, Appl. Biochem. Bioeng. (submitted).

Tewari, Y.B., Thermodynamics of hydrolysis of disaccharides: cellobiose,

gentiobiose, isomaltose, and maltose, J. Biol. Chem. (submitted).

Vaney, M-C, Gilliland, G.L., Harman, J.G., Peterkofsky, A. and Weber, I.T.,

Crystal structure of a cAMP- independent form of catabolite gene

activator protein with adenosine substituted in one cAMP-binding site,

J. Biol. Chem. (submitted).

6. CONFERENCES

A symposium on Fundamental Biochemical Processes was organized by R.N.

Goldberg and Y. Tewari as part of the 43rd Annual Calorimetry Conference,

Bartlesville, Oklahoma, August 1988.

22
TECHNICAL ACTIVITIES

OF THE

CHEMICAL KINETICS DIVISION

S.G. Lias, Chief

1. INTRODUCTION

Chemical kinetics is the discipline which treats the rates of chemical

reactions, the factors which influence those rates, and the detailed

mechanisms of the reactions. The process of transformation of one chemical

compound into another is the very essence of chemistry, and the understanding

of chemical reactivity is an important goal of science. Through combustion,

energy is generated for electricity, automobiles and aircraft, and other

needs of society. Through the medium of chemical reactions, industry takes

raw materials and converts them into useful products , including therapeutic

drugs. Only through an understanding of chemical rates and reactivity is it

possible to comprehend complex environmental phenomena, such as variations in

the ozone layer or the formation of acid rain.

The primary focus of the Division's programs is the generation of

compilations and data bases of high quality evaluated chemical kinetic data

adapted to the needs of various communities involved in work on applications

of chemical kinetics; applications include chemical process development,

environmental processes, combustion, and analytical chemistry. The work of

the Division not only organizes a wide spectrum of kinetic data and

thermodynamic properties of reactive intermediates for the industrial and

academic communities, but also utilizes this data to extract general

reactivity patterns and develop improved predictive theories and models.

Major areas of uncertainty revealed in the course of evaluation activities

often prompt studies in the experimental programs of the Division. The

considerable breadth of ongoing experimental activities in the Division

ensures that the expertise and insight needed for good data evaluation is

available

Another significant focus of Division programs is the development of

measurement techniques to aid in the detection of reactive intermediate

species for kinetic studies, as well as measurement techniques which utilize

kinetics for other purposes, such as chemical analysis.

2. GOAL

The Chemical Kinetics Division is responsible for providing high quality

evaluated chemical kinetic data for use in designing, controlling, and

optimizing a wide variety of chemical processes. Associated experimental

programs obtain benchmark data for compilations and data bases, and also

provide reliable chemical kinetics data, measurement methods, theoretical

23
concepts, and models of chemical reactions and reaction mechanisms. The

applications include combustion, new chemical feedstocks and technologies,

atmospheric and planetary chemistry, effects of ionizing radiation on

materials, biotechnology, flue-gas cleanup chemistry, acid rain, and toxic

waste incineration. The Division works closely with industry and other

government agencies directly and through technical standard- setting groups.

3. GROUP FUNCTIONS

The Chemical Kinetics Division is formally divided into four groups, but

there is considerable overlap in the technical interests and even the

personnel of the groups, as well as a great deal of variation in the nature

of projects within a group. Three of the groups deal with experimental work

and are loosely organized according to the type of experimental apparatus

used. These are: (1) Ion Kinetics (which includes all the research carried

out on three kinetic mass spectrometers); (2) Neutral Kinetics (projects

involving kinetics of non- ionized reactants- -mainly free radicals are studied

using various spectroscopic detection techniques or end-product analysis)

and (3) Radiation Chemistry and Kinetics (studies involving both ionized and

non- ionized reactants generated by electron accelerators or gamma radiation).

Most (but not all) of the expertise in the Division on condensed phase

kinetics is found in the last group. The fourth group (Data Centers)

includes three data centers, and encompasses all the projects associated with

the compilation and evaluation of kinetic data. Scientists from the other

three groups are heavily involved in this data-related work.

In this report, data evaluation activities will be presented according

to subject along with the discussion of the corresponding experimental

programs, even though the data centers are organized into a separate group.

A separate discussion will be given of some of the data centers' activities

connected with the development of distributable PC versions of the data bases

of the Chemical Kinetics Division.

4. SELECTED PROJECT SUMMARIES

NEUTRAL KINETICS GROUP AND RELATED DATA CENTER ACTIVITIES

Combustion Chemistry: Chemical Kinetics Data Center Activities

W. Tsang, J. Herron, W. G. Mallard, R. Levin, F. Westley (Contractor), G.

Zumwalt

A long range program in the Division, supported by the Department of

Energy and the NIST Office of Standard Reference Data, has the goal of

developing a quantitative understanding of the kinetic behavior of organic

systems at high temperatures. In particular, work has been aimed at

producing a complete data base of self-consistent, evaluated kinetic data for

use in modeling hydrocarbon combustion. Recently, with external support from

the Department of Defense, new activities have been initiated to expand the

combustion data base to include compounds of interest for propellant

combustion. The existence of a high quality combustion data base will

24
eventually make it possible to do away with extensive empirical testing in

process design and optimization. The research program includes both the

evaluation of thermal rate data important for combustion phenomena and a

related program of experimental studies (described immediately below) which

are driven by the needs of the data evaluation program.

Data activities on combustion kinetics are a primary activity of the

Chemical Kinetics Data Center; W. Tsang is the senior data evaluator. During

the past year, the data activities resulted in several important outputs.

The archive of unevaluated chemical kinetic data for combustion chemistry

(1971-1982) was published in the NSRDS-NBS series. This data base contains

rate data on over 1900 elementary reactions. This core data base will be the

basis of a more general chemical kinetics data base which will eventually

include all kinetic data on gas phase chemical reactions. A supplement

covering the literature published in 1983 has also appeared. Relevant

publications are being identified and collected from the literature on a

continuing basis. The total number of reactions covered in the data base now

exceeds 2500.

The evaluation of the data to produce a self-consistent data base has

resulted in four publications to date, which present a complete evaluation of

data on combustion of the C 1 -C4 alkanes and methanol. The initial

publication dealt with reactions involving methane, and Part 2 contained data

on 64 elementary reactions involved in methanol combustion. During the past

year, the third installment in this series, dealing with the reactions of

propane, n-propyl and isopropyl radicals, was published (Journal of Physical

and Chemical Reference Data) , and the fourth evaluated compilation, dealing

with the reactions of isobutane, isobutyl and t-butyl radicals, is in press.

The evaluated combustion data base now covers about 500 interactions of 35

reactive species.

Evaluation of existing experimental data on propene , allyl radical and

2 -butene, carried out during the past year, extends the data base to include

the reactions of unsaturated molecules and radicals. Where no experimental

data are available, results from related systems have been used to

extrapolate and interpolate. Development of these procedures has proved to

be an important part of this work, since the multiplicity of possible

reaction channels means that experimental data for these systems are

generally incomplete. A paper will be published in Combustion and Flame on

the methodolgy developed for extrapolating unimolecular rate data over

extended temperature ranges.

New directions for the evaluated combustion data base have been dictated

by important recent developments in the fundamental understanding of

propellant combustion. At the recommendation of the JANNAF Panel on Kinetic

and Related Aspects of Propellant Chemistry, and with the support of the Air

Force Astronautics Laboratory and the Ballistics Research Laboratory, a

program to supply the chemical kinetic data base for the gas phase

decomposition of RDX is being initiated. A very important aspect of this

data base will be the inclusion of reactions involving nitrogen- containing

species such as NO, NO2 , HNO, and HCN. This work will complement the data

base for hydrocarbon combustion.

25
Combustion Chemistry: Experimental Studies

W. Tsang, J. Walker (Contractor)

The experimental studies on combustion kinetics, which are carried out

in two heated single-pulse shock tubes, have concentrated on unimolecular

decompositions and reactions of hydrogen atoms with unsaturated species.

There is a paucity of experimental results for these reactions, which are of

interest for the data evaluation efforts. During the past year, studies have

been published on the hydrogen atom- induced decomposition of phenol, aniline,

isobutene, and a variety of chlorobenzenes, and additional work on reactions

of o-chlorophenol , acetone, and dimethylether with H-atoms has been

completed. The data generated in these studies have provided us with

information which permits predictions of the rates and mechanisms of hydrogen

attack on many unsaturated systems.

The studies of hydrogen atom reactions with polychlorinated benzenes

(supported by the Office of Renewable Resources, DOE) are of importance

because of the production of related toxic compounds (dioxins) in the

incineration of hazardous wastes. Our approach to the problem treats the

introduction of chlorinated species as a perturbation on the overall process

of hydrocarbon combustion. The nature and relative amounts of the effluents

that are frequently observed can be demonstrated to arise almost entirely

from pockets of improperly mixed gases; a pyrolytic mechanism must govern the

observed distribution.

A study of the unimolecular decomposition of 3 -phenyl -2 -butene to give

benzyl and propenyl radicals was published. The results lead to a heat of

formation for the vinyl C-H bond in propene of 460+8kJ/mol, a value which is

very close to that taken for the data evaluations; the results do not support

the low values suggested by some recent work. A very interesting consequence

of this work is the implication that vinyl radical combination processes are

very fast. Finally, in the area of nitro-organic chemistry, recent

experimental results demonstrate that the main mode of decomposition of o- nitrotoluene is to form anthranil. This has very interesting implications

with respect to the nature of the initiating process in TNT decomposition.

Other studies involve the unimolecular decomposition of tetralin, phenotole,

butylphenyl ether, n-amylbenzene , diethylether , and

3,3,4 , 4- tetramethylhexane

Kinetics of Environmental Processes: Chemical Kinetics Data Center Activities

R.F. Hampson, J. Herron, F. Westley (Contractor)

The Chemical Kinetics Division has a long history of participation in

the NASA Upper Atmosphere Research Program, with the Chemical Kinetics Data

Center playing a key role. For example, two Division scientists are members

of the NASA Panel for Data Evaluation; the Panel provides the definitive

recommendations of chemical kinetic and photochemical data to researchers

engaged in modeling stratospheric chemistry with an emphasis on ozone

perturbations. For this Panel, the Chemical Kinetics Data Center has the

primary responsibility for evaluation of the chemical kinetic data for all

26
reactions involving halogenated species. For each reaction, a recommended

rate constant value, with a measure of its reliability and supporting

documentation, must be provided. This work is also driven by participation

in the IUPAC Commission on Chemical Kinetics, Subcommittee on Gas Kinetic

Data Evaluation for Atmospheric Chemistry. Our data center personnel have

had primary responsibility for evaluation of the chemical kinetic and

photochemical data for reactions of halogenated species, and currently also

have primary responsibility for reactions involving nitrogen- containing

species and oxygenated species.

These significant contributions to the body of gas -phase reaction

kinetic data have an importance beyond the immediate goals stated above. The

data also provide a basis for understanding fundamental energy exchange

effects in unimolecular decompositions, correlating reactivity with molecular

structure, and predicting reactivity in the aqueous/solution phase from gas

phase data or vice versa. Further, most of the work is closely related to

understanding combustion processes; indeed, some of the experimental results

are equally important for both data bases

Kinetics of Environmental Processes: Experimental Studies

M.J. Kurylo , T.J. Wallington (Oxford University, England), P. Dagaut

(University of Orleans, France), R. Liu (Chinese Academy of Sciences, China)

In this research program, we carry out chemical kinetic studies which

have direct applicability in important areas of atmospheric (as well as

combustion) chemistry. The choice of experimental problems is strongly

influenced by the needs of the data evaluation effort discussed above. For

example, we obtain kinetic results which have applicability to understanding

the formation of acid rain in the troposphere, the depletion of ozone in the

stratosphere, or the formation of noxious pollutants through the burning of

fossil fuels or through the atmospheric oxidation of organic effluents. In

such areas, we have recently witnessed an impressive application of

fundamental chemical kinetic and photochemical data towards the solution of

problems in earth- system science.

In the experimental program, spectroscopic measurement techniques are

applied to the detection and characterization of the chemical kinetics of

small gas -phase free radicals in a controlled reactive environment. The

experiments lead to highly accurate rate constants which are essential input

parameters in the numerical modeling of complex chemical systems.

Due to the important role that peroxyl radicals play as intermediates in

atmospheric and combustion chemistry, recent work has been concerned with

determining the ultraviolet spectra and measuring reaction rate constants for

peroxyl and alkylperoxyl radicals. Other work has addressed the reactions of

oxygenated organic compounds (alcohols, ketones, ethers, esters, and acids)

with OH radicals; these reactions are the most significant oxidative step for

these compounds in the earth's atmosphere, as well as in combustion systems.

Despite the increasing atmospheric abundance of such organic oxygenates, due

to their emission during industrial or commercial use or their formation as

intermediates in organic combustion, until now there have been relatively few

27
laboratory studies of the reactions with OH. The experiments were performed

using the flash photolysis resonance fluorescence technique under conditions

which permitted calculations of atmospheric lifetimes for the organics.

Through these studies, a vast body of experimental chemical kinetic gas

phase data has been assembled for many molecules not previously addressed.

For the first time, a detailed comparative analysis between the gas phase

results and those from aqueous/liquid phase studies with the same molecules

has been made. This correlation permits fairly accurate estimation of gasphase rate constants when data exist only in the liquid phase or vice versa.

This, in turn, helps to remove many of the measurement uncertainties

associated with both gas phase and solution phase studies. Furthermore, such

a correlation can potentially extend to the solution phase, the use of semiempirical predictive techniques developed for gas -phase reactions based on

structure-activity relationships such as discussed above.

During the coming year, experiments on the pressure dependent

combination of CIO radicals will be initiated. Formation of the (CIO )

dimer

is considered to be an important process involved in the chemistry associated

with the formation of the Antarctic ozone hole. Additional experiments will

be conducted during the next several months aimed at determining the

atmospheric lifetimes for several of the alternate compounds which are

proposed by the chemical industry as replacements for chlorofluorocarbons

(CFC's). This work is being coordinated with representatives of the Chemical

Manufacturer's Association.

Planetary Atmospheres

J. Herron, W. Braun, A. Laufer (DOE), A. Fahr (Contractor)

A related project supported by the NASA involves investigations of the

chemistry of radicals which are expected to play an important role in certain

carbon-rich atmospheres. During the past year, attention centered on studies

of the vinyl radical. The vacuum ultraviolet (VUV) absorption spectrum of

the vinyl radical has been identified, making possible time-resolved kinetic

studies of this radical. A high- temperature reactor is being constructed for

further studies of the kinetics of vinyl radical reactions.

Mechanisms of Laser Chemical Vapor Deposition: Experimental Studies

W. Braun, H. Okabe (Contractor), R. Klein (Contractor), I. Price (Guest

Researcher)

A newly initiated program to study the mechanisms of laser chemical

vapor deposition has recently been funded by the Department of the Army. The

work will involve studies of the photodissociation of organometallic

compounds of the Group III-V elements. Under this program, work will be

carried out to (1) measure the vacuum ultraviolet absorption cross sections

for a number of organometallic compounds, (2) design and construct an

apparatus to monitor resonance fluorescence -absorption to allow measurement

of the time histories of the elements produced in these systems both in their

ground and excited electronic states, (3) design and construct an apparatus

28
for vacuum ultraviolet laser photolysis and kinetic absorption detection to

permit measurement of the time histories of various free radical species

produced in the photodissociation process, and ( 4 ) measure the quantum yields

of the major end-products produced in these systems. Such measurements will

allow us to better understand the photochemical dissociation process and how

the dissociation process is affected by laser wavelength and laser intensity,

and how the reactive intermediates are subsequently influenced by the

composition of the gas mixture and the reactor temperature. Final objectives

will include a specification of the most suitable photolytic methods for

producing both uniform and clean metal-atom films possessing optimum

semiconductor properties.

Multiphoton Ionization Spectroscopy of Transient Free Radicals

J.W. Hudgens, R.D. Johnson, III

Resonance enhanced multiphoton ionization (REMPI) spectroscopy provides

new, previously unobtainable, data about the electronic structures of a wide

variety of free radicals. The procedures used to observe these spectra also

lead to very sensitive and selective schemes for the optical detection of the

radicals. The technique can detect reactive intermediates not detected using

laser induced fluorescence (LIF) , Raman, or CARS spectroscopies. The

technique involves tuning an intense pulsed dye laser so that the energy sum

of two photons of laser light matches the energy of a Rydberg state of the

radical of interest, thereby generating an ion which is detected by mass

spectrometry

This year marked a strong shift in the orientation of the REMPI research

toward the study of systems of interest for semiconductor materials

processing. REMPI detection schemes were developed for numerous silicon and

germanium containing free radicals including SiH3, SiCl, SiH, GeF, GeCl, and

GeH3 , and also for CHF2, CCI3 , CHFC 1 , CF2CI, and CFCI2. Other work completed

included the investigation of the spectra of cis- and trans-2-butene-l-yl , a

pair of methyl substituted allyl radicals.

Substituent Effects and Bond Strengths

S.E. Stein, R. Chen,* M. Suryan,* F.-M. Wang,* A. Fahr (Contractor)

A systematic series of studies on the effects of substituents on carboncarbon and carbon-oxygen bond strengths has been completed. Studies of

substituted anisoles (me thoxybenzenes ) revealed very strong effects which

generally followed known trends for cationic reactions. Ortho hydroxyl and

amino groups had exceptional bond weakening effects, probably due to a strong

hydrogen bond in the product radical. Studies of ethylbenzenes showed much

smaller and qualitatively very different effects. These measurements allowed

the placement of a substantial amount of existing Electron Spin Resonance

(ESR) work of these radicals on an absolute scale. A series of reactions

generating substituted methyl radicals placed the stabilities of these

ubiquitous radicals on an accurate relative scale for the first time. Trends

were similar to, though effects were much larger than, those seen for benzyl

radicals. This work represents the first extensive series of studies of the

29
thermodynamic effects of substituents on bond breaking reactions. This work,

supported by the Gas Research Institute, uses the very low pressure pyrolysis

(VLPP) technique.

*Guest Researchers Sponsored by the Gas Research Institute

Chemical Theory of Graphite

S.E. Stein

Reliable methods have been developed for the estimation of H-atom and

proton affinities of polycyclic aromatic hydrocarbons of arbitrarily large

size. This procedure uses a parameterized form of the Huckel theory which

was previously developed as part of this project for the treatment of large

polycyclics. H-atom affinities depend primarily on the chemical structures

near the site of addition, and for stable molecules differ little from three

rings to infinitely extended systems. Proton affinities, on the other hand,

depend both on nearby bonding and on the overall molecular size. In the

limit of an infinite plane, proton affinities can be increased by as much as

250 kJ/mol by this size effect.

Chemical Kinetics Data Center: Other Activities

J . Herron

Sulfur hexafluoride is widely used as a dielectric in the electrical

power industry and as a source gas in plasma etching processes. Work in the

Chemical Kinetics Data Center on the evaluation of thermochemical and kinetic

data for the species involved in the dielectric breakdown of sulfur

hexafluoride has been extended to a consideration of the thermal stability of

SF5 and S2 F]^o* In addition, a joint effort with the Electrosystems Division

of NIST has as a goal computer modeling studies of the dielectric breakdown

of this compound.

Earlier work on the thermochemistry of S-F compounds has been extended

to some of the organic analogues, the sulfoxides and the sulfones. The

thermochemistry of these compounds has been reviewed and new group values

derived to permit the estimation of thermochemical properties for compounds

for which no data exist. The development of the Plasma Chemistry Data Base

will continue as a collaborative effort with the Electrosystems Division

supported in part by the NIST Office of Standard Reference Data (OSRD)

Related experimental work is carried out in the Chemical Kinetics Division by

L.W. Sieck.

The compilation of gas-phase chemical kinetic data for all types of

thermal gas -phase reactions is an ongoing activity of the Data Center. In

order to retrospectively expand the coverage of the chemical kinetics data

base to the earlier literature and to include reactants containing atoms such

30
as chlorine or silicon, which were not included in earlier coverage, data

from older articles will be compiled for eventual addition to the data base.

This work is supported jointly by the NIST OSRD and the DOE.

The Second International Conference on Chemical Kinetics is currently

being organized; it is to be held at NIST in July, 1989. Planning and

implementation are being carried out using facilities of the Data Center.

ION KINETICS GROUP AND RELATED DATA CENTER ACTIVITIES

The Ion Kinetics Group has undertaken several projects utilizing kinetic

mass spectrometry to study the chemical kinetics of ionized species. One

important focus of the program is the development of experimental

technologies and data bases for use in analytical chemistry laboratories.

Projects include the development (under the sponsorship of the Department of

Energy) of new analytical schemes for use with chemical ionization mass

spectrometry and the standardization of operating conditions for the MS/MS

analytical technique. The Division's new Mass Spectrometry Data Center

maintains the well known data base of analytical mass spectra which is

distributed by the NIST Office of Standard Reference Data.

The NIST/EPA/MSDC Mass Spectral Data Base: Establishment of a New Data Center

S.E. Stein, S.G.-Lias, S. Kafafi (Univeristy of Cairo, Egypt), G. Mallard,

R. Levin

A large computerized database of analytical mass spectra, originally

developed 20 years ago by scientists at the EPA and NIH, has been distributed

by the NIST since 1978, under an interagency agreement which assigned to EPA

the responsibility for maintenance of the data base. The data base is used

in the data systems of analytical mass spectrometers, and therefore,

thousands of copies are in use in instruments around the world. The data

base, in fact, is one of the most visible and widely known products

distributed by NIST.

In 1987, S.E. Stein of the Chemical Kinetics Division developed a PC

version of this data base with search software which was released for

distribution to the public in September, 1987. During the first year after

its release, this PC data base sold more copies than all other data bases

distributed by NIST. Because the new PC capability made the data base more

conveniently accessible to NIST scientists than it had been before, and

because it was desirable for NIST to have better control over the quality of

spectra in the data base , the Office of Standard Reference Data decided to

bring the primary responsibility for the maintenance, evaluation, and

updating of the data base into NIST from EPA. Accordingly, plans were made

for a new Data Center, which was established on October 1, 1988.

During 1988, all of the functions necessary to produce a new edition of

the Data Base were transferred from EPA to NIST. This involved a transfer

of the archive of 77 000 mass spectra from the EPA computer, the translation

of the archive to a PC version, the preparation of software to pinpoint

errors in spectra, and the adaptation of the EPA "Quality Index" algorithm

31
for the evaluation of the spectra. In addition, about 7000 new spectra were

added to the archive. Some 2750 of these were obtained in an international

exchange with the Soviet Union. This represented the largest increase in the

size of the data base for many years and was the result of one year's work of

the incipient Data Center.

During the coming year, the effort to improve and enlarge the data base

will continue. Activities will include: (a) the location of errors in

archival spectra and (depending on the nature of the error) the elimination

of the spectrum from the archive or the correction of the error, (b) the

examination of replicate spectra which differ from one another in any

significant feature, and the choice of the better or best spectrum for

inclusion in the data base, (c) the location of CAS Registry Numbers and

addition of new spectra, as described above, and (d) the addition of new

information on chemical structures. The work will continue on identifying

compounds in the archive for which the existing nomenclature is obscure.

There are several thousand poorly identified spectra in the archive which may

eventually be retrieved for inclusion in the data base, and several thousand

additional spectra which contain errors which can be corrected, thereby

making the spectra eligible for inclusion.

Standardization of Tandem Mass Spectrometers

R.I. Martinez, B. Ganguli (Georgetown University)

The goal of this project is to determine experimentally whether it is

feasible to build standard reference data bases for the widely used

analytical technique, tandem mass spectrometry or MS/MS. Tandem mass

spectrometry, a powerful technique for the analysis of multicomponent

mixtures, is used extensively in a variety of applications. There are more

than 300 analytical MS/MS instruments worldwide, and there has been much

discussion about the need for a generic, instrument- independent data base for

use with such instruments. However, a 1984 international interlaboratory

comparison demonstrated that spectra taken on different instruments under

nominally the same operating conditions could be radically different; a

spectrum measured for known species in one such instrument cannot be used to

identify those species in a different instrument.

The analysis involves generating the electron mass spectrum of the

sample in the first chamber (the first mass analyzer, called X]^) , massselecting a particular ion from that spectrum to be sent into a second

chamber (an RF-only quadrupole mass filter, Q2 ) where it interacts with a

target gas, which brings about "collisionally-activated" dissociation (CAD)

of the ion. The CAD spectrum which is observed (in Q3 , the third mass

analyzer) thus represents a mass spectrum of a particular ion, usually a

fragment ion in the original spectrum. The poor irreproducibility of spectra

from one instrument to another can be traced to problems in the complex ionoptics of such instruments, i.e. poor ion containment within Q2 or fringing

fields between Q2 and Q3

.

32
Under this project, which has been supported by the Environmental

Protection Agency and by the Air Force, it has been established that

instrument- independent branching ratios can be measured under s ingle - collision conditions. The data being generated constitute the first elements

of an absolute (generic) CAD spectral library. The current focus of the

experimental work is: (a) to characterize the structures and dissociation

dynamics of polyatomic ions, namely C 2H30

+ ions from a variety of source

compounds, by measuring absolute reaction cross sections and branching ratios

for CAD; (b) to assess the energy disposal in ion/molecule reactions (1-200

eV collisional energy range) ; and (c) to study collisional energy exchange

in polyatomic molecules and molecular ions.

A second international interlaboratory comparison to assess which

instruments are capable of generating instrument- independent spectra is now

being directed by Martinez. Participants include instrument manufacturers

as well as industrial and academic laboratories. Preliminary analysis of the

data indicates that at least 50% of the instruments currently in the field

can provide instrument- independent spectra.

Gas-Phase Thermochemical Properties of Ions: Ion Kinetics and Energetics

Data Center

S.G. Lias, R.D. Levin, S. Kafafi (University of Cairo, Egypt)

This Data Center handles other types of mass spectrometric data, namely

ionization energies, appearance energies, proton affinities, electron

affinities, and related heats of formation of ions. The Data Center also has

as a goal the building of a data base of rate constants for ion/molecule

reactions

A major publication of the Data Center, "Gas -phase Ion and Neutral

Thermochemistry" by S.G. Lias, J.E. Bartmess, J.F. Liebman, J.L. Holmes, R.D.

Levin, and W.G. Mallard, was published in the Journal of Physical and

Chemical Reference Data during the past year. The publication gives

evaluated heats of formation of approximately 8000 ions (5700 cations and

2400 anions) . This landmark publication is an update of a 1978 NBS

publication that sold over 1000 copies.

The 1984 Data Center publication "Evaluated Gas Phase Basicities and

Proton Affinities of Molecules; Heats of Formation of Protonated Molecules"

was the second most widely cited paper of that year; if 1987 citations are

included in the analysis, the paper was the most cited publication. New data

on approximately 500 molecules are being evaluated for an update to this

publication, to be submitted for publication in 1989.

During FY88, the decision was made to expand Data Center activities to

include the thermodynamics of ionic clusters, a field which is experiencing

much interest now. Michael Mautner, a recognized expert in this area, has

expressed an interest in building an archive of data and evaluating the

collected data. The literature search will be started during FY89.

33
Gas-Phase Thermochemical Properties of Ions: Experimental Studies

L.W. Sieck, S.G. Lias, P. Ausloos, T. Buckley, M. Mautner

The generation of thermochemical information from gas -phase ion/molecule

equilibrium constant determinations, and other ion/molecule reaction studies,

is a long-standing activity of the kinetic mass spectrometry laboratories.

The impetus for the work, which involves both the pulsed high pressure

instrument and the ion cyclotron resonance spectrometer, is the ongoing data

center activity concerned with ion energetics. The experimental program

provides benchmark data needed for the evaluation activities.

During the past year, the ion cyclotron resonance instrument has been

upgraded by the addition of a Fourier transform capability, which will

provide much more accurate equilibrium constant and rate constant data in

future studies.

Work involving the establishment of an absolute gas -phase acidity scale

is continuing on the high pressure mass spectrometer. The goal of this

extensive project is to define an interlocking ladder of acidity values

relative to reference standards; we will investigate equilibria of the type

A" + BH = AH + B" as a function of temperature. The scale in current use is

based on such measurements carried out at a single temperature, i.e., a

ladder of free energy changes. In the absence of temperature -dependence

data, these are converted to the corresponding ladder of enthalpy changes

(acidities are related to the enthalpy changes) by assuming values for the

entropy changes. The study in progress provides experimental data for the

enthalpy and entropy changes. Analogous work concerned with proton transfer

equilibria involving positive ions is also in progress.

Other work involves determinations of the thermochemistry of association

ions such as R0“ HSR, RS' HSR, RS" HOR, and CH3CO2" HOH, etc. The

objective of this work is to develop correlation lines, for predictive

purposes, which relate the dissociation energies to differences in the gas

phase acidities of the two molecular partners. Such results have

implications for predicting liquid-phase behavior from gas-phase data.

Plasma Etching: Experimental Studies (Reactions in SF5)

L.W. Sieck

A high pressure mass spectrometry study of the reactivity of SFg" toward

a variety of fluorinated gases and SO2 was completed. Although no reaction

of any type was detected with SOF2 and SO2F2 , efficient F" transfer was found

in all of the other systems. All of the reactions exhibited a negative

temperature coefficient, i.e., the rate constants decrease substantially with

increasing temperature. The various reactions studied were used to provide

additional information concerning the gas phase F“ affinity scale. The

placement of SF5 in the scale indicates that SF^" is reactive towards several

of the major stable by-products generated during electrical breakdown in SF5.

The information derived from these studies was used to generate a computer

model which predicts the behavior of oxy- fluoride production during corona

34
discharge in high pressure SFg ; this in turn will provide new insight into

the processes occurring in vapor- insulated high voltage systems and during

plasma etching, both of which incorporate SF5 as the gaseous dielectric.

This work is carried out in collaboration with the Electrosystems Division of

NIST.

RADIATION CHEMISTRY AND KINETICS GROUP

The Group aims at achieving a fundamental understanding of the effects of

radiation on chemical and biochemical systems and utilizing radiation

techniques for chemical kinetic measurements. Kinetic studies are carried out

by pulse radiolysis (using a field emission source and a Van de Graaff based

system with optical detection) and are supplemented with laser flash

photolysis experiments. The aim of these studies is to understand the

chemistry of reactive intermediates in solution and in biochemical systems.

In general, these studies include examination of the mechanisms, rate

constants, and equilibrium constants of reactions in a variety of chemical

systems such as organic radicals and radical ions, inorganic radicals, and

metalloporphyrins , both in aqueous and in nonaqueous solutions. Reactions of

radicals with biological materials are also studied by product analysis using

HPLC, GC-MS, NMR spectroscopy, and high-resolution mass spectrometry

techniques. The scientific emphasis of the work also leads to data evaluation

efforts and to published compilations of evaluated data. Accomplishments of

the past year are described below.

Solar Energy Conversion and Storage: Metalloporphyrins and Colloidal Catalysts

P. Neta, G.S. Nahor (Hebrew University, Israel), S. Mosseri (Ben Gurion

University, Israel) and A. Harriman (Royal Institute, England)

Metalloporphyrins may serve as efficient photosensitizers for solar

energy conversion and storage. This is due not only to their broad absorption

spectra in the visible light range but also to the rich redox chemistry of the

various metalloporphyrins. The general aim of the project is to understand

the electron transfer reactions of the various metalloporphyrins in order to

be able to apply them in the photochemical decomposition of water to hydrogen

and oxygen. The pulse radiolysis experiments are designed to concentrate on

individual steps to obtain full understanding of each particular reaction and

to develop the conditions for its optimal efficiency in order to incorporate

it at a later stage in an overall solar energy conversion system.

In recent years, a research effort of this group has been concerned with

the catalyzed oxidation of water to oxygen by oxidized forms of

metalloporphyrins. An initial result was the finding that certain

metalloporphyrin radical cations react with ruthenium dioxide catalysts in

aqueous solutions to yield oxygen. It should be possible to optimize the

efficiency of this process through changes in the nature of the catalyst and

the porphyrin and changes in the reaction conditions. In the past year

colloids of iridium oxides were prepared from chloroiridate ions by radiolysis

and by chemical reactions in the presence of polymeric stabilizers. These

colloids reacted with metalloporphyrin radical cations more rapidly than the

35
RuC> 2 colloids and catalyzed water oxidation to C>2 . More importantly, oxygen

production photosensitized by ZnTSPP was evident at pH>7 with IrOx , as

compared with pH>9 with Ru(>2 , indicating a lower overpotential for the IrOx

colloids as compared with that of RuC>2

Other work involves investigating the reduction of water to H2 on the

surface of metal colloids. Pulse radiolysis is used to measure the

bimolecular rate constants for transfer of an electron from a reducing radical

to a colloidal platinum particle in neutral aqueous solutions. Radicals

derived from various viologens, pyridines, and benzophenones reacted mostly

with diffusion-controlled rates. Only the radicals from a negatively charged

benzophenone derivative and p-nitrobenzoate ion reacted more slowly. The

rates of reaction depend on the reduction potential of the compound, the

charge of the radical, and presumably the self exchange rate. The differences

between the various compounds were also expressed in the rate of hydrogen

production by these compounds. Future work will explore the possibility of

reducing molecules other than water on the surface of metal colloids, for

example, reduction of N2 to NH3

Radiation Chemistry of Organic Systems

P. Neta, S. Mosseri,* Z.B. Alfassi*

Since the redox reactions of some of the porphyrins discussed above have

been studied in irradiated acetonitrile or methylene chloride, and since these

solvents are often used for electrochemical studies on porphyrins, it appeared

worthwhile to devote some attention to the basic radiation chemistry of these

important solvents.

Studies on acetonitrile showed that cyanide ions are released upon

radiolysis of the neat solvent or of its aqueous solutions, but only in the

presence of oxygen. The mechanism involves formation of the acetonitrile

radical, -CT^CN, which reacts with O2 to give the peroxyl radical (NCd^C^*)-

Subsequent reaction of the peroxyl radical results in the release of HCN.

Dichlorome thane (DCM) is used as a solvent for radiolytic oxidation of

various compounds. Therefore, the nature and the radiolytic yields of the

various radicals produced in irradiated DCM were studied. Radiolysis of DCM

leads to formation of primary oxidizing radicals and carbon-centered radicals.

The latter react with oxygen to yield peroxyl radicals. The yields and

chemical behavior of these intermediates were studied by pulse radiolysis of

DCM solutions containing various solutes: phenols, anilines, dimethoxybenzene

,

hexamethylbenzene , cyclohexene, dimethylsulfoxide (DMSO) , and zinc

tetratolylporphyrin. At low concentrations, some of these solutes were found

to be oxidized by two peroxyl radicals, CH2CIO2* and CHCI2O2', with different

rate constants. At higher concentrations, the solutes react also with the

primary radicals (Cl atoms and the radical cations CH2Cl2' +

) with diffusioncontrolled rate constants. Cl atoms were found to be very reactive in

electron transfer as well as addition and hydrogen abstraction reactions.

*(Ben Gurion University, Israel)

36
Study of Reactions of Peroxvl Radicals

P. Neta, R.E. Huie , S. Mosseri,* Z.B. Alfassi,* L.V. Shastri**

Peroxyl radicals are important intermediates in radiation chemistry and

biology and play a major role whenever an organic radical is formed in the

presence of oxygen. Peroxyl radicals are capable of oxidizing porphyrins,

and the mechanism appears to involve an inner sphere electron transfer with an

intermediate binding of the radical to the metal center. Recently the rates

of oxidation of iron porphyrins, as well as of several organic substrates, by

the three halogenated peroxyl radicals, CF3O2, 001302, and CBr302 were

compared. The order of reactivity of these radicals did not follow the

usually- observed natural order; the ratios of electron transfer rate constants

are generally 5 : 1 : 2 .

To examine the effects of solvents and of substituents on an authentic

outer sphere electron transfer reaction of peroxyl radicals, the reaction with

chlorpromazine was chosen as a model. The rate constants for electron

transfer were found to depend very strongly on solvent polarity (in various

mixtures of water, 2 -propanol, and haloalkane) and a good correlation was

obtained between log k and the dielectric constant of the solvent mixture.

This work was extended to studies with ascorbate, urate, and trolox. Again,

the rate of oxidation by peroxyl radicals was found to be dependent on solvent

polarity, and a detailed examination of this effect for a variety of radicals

is under way. The solvent effect appears to be strong for the strongly

oxidizing peroxyl radicals, such as the halogenated alkylperoxyl , but much

weaker for the weakly oxidizing nonhalogenated alkylperoxyl, a puzzling result

which is being investigated further.

A detailed study of the rate of oxidation of ascorbate by a large number

of substituted methylperoxyl radicals was carried out. The absolute rate

constants were found to increase as the electron withdrawing capacity of the

substituent on the peroxyl group increases. A linear correlation is observed

between log k and the Taft substituent constant cr* for a wide variety of

substituents. However, the points for peroxyl radicals that contain halogens

on the a-carbon do not lie on the same line as those for the other

substituents. This finding of more than one line for such a linear free

energy correlation was corroborated with other compounds and suggests that the

details of the electron transfer mechanism to peroxyl radicals vary somewhat

with the electron affinity of the radical.

* Ben Gurion University, Israel

**Babah Atomic Research Center, India

Study of Reactions of Inorganic Radicals

R.E. Huie, P. Neta, C.L. Clifton, S. Mosseri,* Z.B. Alfassi*

Small, inorganic free radicals play key roles in many important chemical

systems, for example, chemical transformations in atmospheric droplets, flue

gas scrubbers, water treatment using either chemical or irradiation

37
techniques, and in biological systems. The most important inorganic free

radical, OH, has been thoroughly studied; far less effort, however, has been

expended on the many other free radicals likely to be important in these

systems

The autooxidation of SO2 in aqueous solutions not only is a primary

mechanism for the acidification of precipitation, but it is also critical in

the behavior of flue gas scrubbers and in the biological effects of ingested

sulfites. We have had an ongoing interest in the mechanism of this reaction,

and in the past this project has generated a considerable body of data on the

chemical reactions of the radicals S02~, SO3", SC>4

-

, and SO5-. During the

past year, absorption spectra, self -reaction rate constants, and rate

constants for the reactions of SO2" and SO3" with O2 were determined. Both

pulse radiolysis and flash photolysis were used in this study; the use of each

complements the other. Among the more interesting conclusions is that the

self -reaction of the SO2" radical does not lead directly to dithionite,

S204^’, but rather first forms an intermediate which then slowly rearranges to

that product. Another study relating to the autooxidation of SO2 involved the

reactivity of HO2 and O2" toward HSO3' and SC^". Essentially, 02“ was found

to be unreactive and HO2 was found to react slowly with HSO3'. Of

considerable importance in the chemistry of atmospheric oxidation of SO2 , was

the observation that both HO2 and O2" react rapidly with SO5'. This reaction

could serve as a chain- termination reaction, so that atmospheric HO2 might

inhibit rather than initiate the oxidation of SO2 in droplets.

Other studies of electron transfer reactions of inorganic radicals have

been initiated because of the importance of these radicals in many chemical

systems, the potential use of these radicals as probes for other systems, and

the possibility that a better knowledge of their chemistry might lead to an

improved theoretical understanding of electron transfer reactions. In recent

years, the redox behavior of a number of inorganic radicals, towards organic

and inorganic compounds, was examined, and the data were utilized for

determinations of the redox potentials of several organic radicals. Recent

additional studies have considered the reactivity of CIO radicals and the

reactivity of Cl atoms uncomplexed with Cl”

Most of the studies on the chemistry of small inorganic radicals have

involved their electron transfer reactions. More complete studies on the

hydrogen- abstraction reactions of some of these radicals are now being carried

out. Rate constants for the reactions of SO4" with several alkanes, ethers,

and alcohols have been measured, and the temperature dependence of the rate

constants was determined for reactions with three of the alcohols. As

expected, the activation energies correlate well with the bond strengths. The

rate constant for the reactions of SO4' with the primary alcohols was linearly

correlated with the number of carbon atoms, up to 1 -hexanol. For the higher

alcohols, however, the rate constant increases more rapidly than expected.

This is the opposite of what has been observed in this Division for the

reactions of OH radicals with primary alcohols in the gas phase. The

reactivity of NO3 toward a series of primary alcohols has also been

determined, with similar results.

*Ben Gurion University, Israel

38
Biotechnology: Development of Biochemical Analytical Methodologies

M. Dizdaroglu, E. Gajewski, A.F. Fuciarelli (University of Alberta, Canada)

The work of this project involves the development of new analytical

techniques for quantifying the effects of radiation or free radicals on DNA

and nucleoprotein. The major thrust of the research has been the development

of a methodology which is capable of separating and identifying, in a single

analysis, the radiolytic products formed in irradiated solutions of

biochemical samples. The methodologies developed in this research provide a

tested analytical method for studying the chemical basis of the biological

effects of free radical -producing processes such as radiation, and a potential

method for the quantification of the process of the cellular repair of DNA

base modifications. The techniques are sensitive enough that radiationinduced DNA damage can be studied at radiation doses which are considered to

be biologically relevant (<10 Gy) . Chemical characterization is achieved by

the use of gas chromatography -mass spectrometry (GC-MS) coupled with selectedion monitoring (SIM). The use of the GS-MS/SIM techniques developed in this

work will in the future lead to a clearer understanding of the chemical basis

of radiation effects on the nucleus of intact cellular systems and the

enzymatic processes of the cellular repair of such modifications.

Within the past year, use of this GC-MS/SIM methodology has led to the

first chemical characterization of a radiation- induced DNA lesion (8,5'-cyclo2 ' -deoxyguanosine) in irradiated cultured human cells, and base damage in

cellular DNA caused by stimulation of human neutrophils. (Neutrophils are a

type of inflammatory cell, which play a key role in the defense of the body

against infection). Also during this year, the separation and identification

of a thymine- tyrosine crosslink (previously identified by this research) has

been extended in vitro to thymine crosslinks with other amino acids in model

systems, as well as in nucleoprotein. The occurrence of crosslinks between

DNA and proteins of nuclear origin in irradiated prokaryotic and eukaryotic

cells has been well documented since the mid 1960's, yet the chemical nature

of this structure has remained elusive. The chemical structure of the

thymine- tyrosine crosslink was conclusively identified as the dimer resulting

from the formation of a covalent bond between the methyl group of thymine and

the 3-carbon of the aromatic ring of tyrosine. The thymine- tyrosine crosslink

has been isolated and conclusively identified in irradiated solutions of calf

thymus nucleoprotein. Its formation is proportional to the dose of gamma

radiation from 300 to 500 Gy. Crosslinks in nucleoproteins between thymine

and other amino acids have also been separated, identified, and quantified.

These studies are unique in that they represent the first chemical

characterization of radiation- induced DNA-protein crosslinks in

nucleoproteins

The mechanism for the formation of DNA-protein crosslinks between thymine

and aliphatic amino acids is thought to involve H-atom abstraction by hydroxyl

radicals from aliphatic amino acids followed by addition of the amino acid

radical to the C(6) -position of thymine, and subsequent oxidation of the

adduct radical. The formation of the crosslink between thymine and tyrosine

in nucleohistone is thought to result from H-atom abstraction by hydroxyl

radicals from the methyl group of thymine followed by the addition of the

resultant thymine radical to the C(3) -position of the tyrosine ring, and the

subsequent oxidation of the adduct radical.

39
Radiation Chemistry and Kinetics Group Data Activities

The Radiation Chemistry and Kinetics Group has produced two data

compilations during the past year in collaboration with the Notre Dame

Radiation Chemistry Data Center, which serves as the natural outlet for data

activities of this Group. The compilation of "Rate constants for reactions of

inorganic radicals in aqueous solution" by P. Neta, R. Huie , and A.B. Ross was

published in J. Phys . Chem. Ref. Data, Vol. 17, p. 1027 (1988), and

"Representative rate constants for radical reactions of biologically important

molecules" by P. Neta and A.B. Ross appeared in "Chemical Kinetics of Small

Organic Radicals," (Z.B. Alfassi, ed.), Vol. IV, CRC Press, p. 187 (1988).

A compilation of rate constants for reactions of peroxyl radicals is

being prepared by P. Neta, R.E. Huie, and A.B. Ross.

DATA CENTERS GROUP

S.E. Stein, J. Herron, R. Hampson, W.G. Mallard, F. Westley (Contractor), R.D.

Levin, G. Zumwalt, S. Kafafi (University of Cairo, Egypt), W. Tsang, S.G. Lias

Three distinct, but closely interacting data centers are active in the

Chemical Kinetics Division. The Chemical Kinetics Data Center is the primary

repository of data on rate constants involving uncharged reactants; the Ion

Kinetics and Energetics Data Center is concerned with rate data for

ion/molecule reactions and data on ionization and appearance energies; and the

newly-established NIST Mass Spectrometry Data Center maintains and updates the

well-known NIST/EPA/MSDC Mass Spectral Data Base .

As has been made clear in the foregoing discussion, the scientific data

evaluation activities are closely tied to the experimental programs and

usually involve the same scientists. In this report, the scientific content

of the data center activities is discussed under the appropriate group

activities to make obvious the close relationships. In this section we

describe the other data center activities. In addition to data evaluation

activities, the centers provide the computer expertise and other support

services for the production of data bases and data compilations by Chemical

Kinetics Division scientists.

Very important progress has been made during the past year in the

computerization of the Chemical Kinetics Division. Data Centers. All the data

base activity is now handled exclusively using personal computers. Versatile

software has been developed for all aspects of the data center activities

including data entry, organization, retrieval, and dissemination. All data

entry now is done using software designed specifically for the chemical

kinetics data programs, which automatically tests for errors and redundancy

and significantly increases the overall efficiency of data entry and

organization. Data evaluation efforts also rely on software developed

especially for use with Chemical Kinetics Division data bases.

Each of the three Chemical Kinetics Division data centers now has a

distributable data base for use on personal computers. The mass spectral data

base was first distributed in a PC version in September 1987, and the Chemical

Kinetics Data Base and Ion Energetics Data base were recently submitted to the

40
NIST Office of Standard Reference Data for internal review. A major update of

the Mass Spectral Data Base was also recently completed.

These PC-data base products have exceptionally short data retrieval

times, made possible because of the extensive use of "index files." The data

bases have been carefully designed to be easy to use and attractive to the

eye. The Chemical Kinetics and Mass Spectral Data Bases allow the user to

generate graphic representations of the data. The formats designed for the

data bases greatly simplify the finding of data and the updating of the data

bases

New search options are being developed for searching modes not feasible

using a conventional hard copy format. For example, the recent update to the

mass spectral data base incorporated innovative new features including the

ability to import and export spectra to and from the data base, the capability

to call the data base programs from other programs, the ability to compare two

sets of graphic data using a split screen, and several sophisticated new

search systems.

An exciting development during the past year, which has important

implications for the work of other NIST chemical data centers, was the

incorporation of information on molecular structure for about 40 000 of the

compounds in the mass spectral data base. A computer tape containing

"connection tables" for most of these compounds was located, a program was

obtained for converting this information to X, Y-coordinates , and it was

modified to use on the PC data files so that the molecular structures can be

displayed graphically. Considering the high level of chemical complexity of

the majority of the compounds in that data base and the inherent difficulty in

deducing complex structures from chemical names, the addition of structures to

the data base vastly simplifies the use of the data base.

Because structural information was not available for many compounds of

interest (for example, for those for which new mass spectra were obtained),

approximately 3500 new structures have now been added to the original

collection of structural information. During the coming year, additional

structures will be added, and structural information will be incorporated into

the other Chemical Kinetics Division data bases. This structural information

will be used in the future for searching the data bases on the basis of

specified chemical structures and for creating smaller, specialized data bases

for specific classes of compounds.

Because of the central role that structural information will play in

future versions of these (and other chemical data bases generated at NIST) , a

complete set of "connection tables" will be maintained in the Chemical

Kinetics Division Data Centers. Industrial users of the data base

enthusiastically support the development of this new resource.

A program for modeling complex chemical reactions, using microcomputers,

has been written and made available to the technical community. This program,

entitled "acuchem," can be used to predict the temporal profiles of reactant

and product species in terms of a set of elementary chemical reactions. The

program is being distributed with a companion graphics program. Over 120

copies have been sent to university, government, and industry laboratories.

41
5. PUBLICATIONS

Alfassi, Z.B.

,

Huie , R.E., Mosseri, S. and Neta, P. , Kinetics of oneelectron oxidation by the CIO radical, Radiat. Phys . Chem. , Vol. 32, p.

85 (1988).

Alfassi, Z.B., Mosseri, S. and Neta, P., The reactivities of chlorine atoms

and peroxyl radicals formed in the radiolysis of dichlorome thane , J.

Phys. Chem. (in press).

Atkinson, R. , Baulch, D.L., Cox, R.A.

,

Hampson, R.F., Keir, J.A. and

Troe , J., Evaluated kinetic and photochemical data for atmospheric

chemistry: supplement III IUPAC subcommittee on gas kinetic data

evaluation for atmospheric chemistry, J. Phys. Chem. Ref. Data

(submitted)

Ausloos, P., Lias, S.G., Buckley, T.J. and Rogers, E.E., Concerning the

formation and the reaction kinetics of phenylium ions, Int. J. Mass

Spectrom. Ion Phys. (submitted).

Billmers, R. , Brown, R.L. and Stein, S.E., Transfer of hydrogen from 9,10-

dihydrophenanthrene to anthracene, Int. J. Chem. Kinet. (in press).

Braun, W. , Scheer, M.D. and Cvetanovic, R.J., Measurement of collisional

v,r,t energy transfer in vibrationally excited SFg using doppler

broadening of the Hg( 6 -*-S 0

- 6 ^P^) multiplet, J. Chem. Phys., Vol. 88 , p.

3715 (1988).

Braun, W. , Price, I. and Scheer, M.D., Hg resonance lamp with controlled

254-nm line profiles for transient temperature measurements, Rev. Sci.

Instrum., Vol. 58, p. 2271 (1987).

Braun, W. and Wallington, T.J., A detailed energy transfer mechanism in

pentafluorobenzene/argon mixtures, Chem. Phys. Lett., Vol. 140, p. 441

(1987)

Braun, W. , Wallington, T.J. and Cvetanovic, R.J., Fluid flow in pulsed

laser- irradiated gases: modeling and measurement, J. Photochem.

Photobiol., A: Chem., Vol. 42, p. 207 (1988).

Braun, W. , Dagaut, P. and Cadoff, B.C., Kinetic studies using a highly

sensitive microphone detector, (submitted to NIST J. Res.).

Brault, D. and Neta, P. , Reactions of iron porphyrins with CF3 , CF3 O2 , and

CBr 302 radicals, J. Phys. Chem., Vol. 91, p. 4156 (1987).

Braun, W. , Kahaner, D. and Herron, J.T., Acuchem: A computer code for

modeling complex chemical reaction systems, Int. J. Chem. Kinet., Vol.

20, p. 51 (1988).

42
Braun, W. , Herron, J.T. and Kahaner, D., AC40 : modeling chemical reaction

systems on an IBM PC, J. Microcomp. App . , Vol. 7, p. 45 (1988).

Budde, W.L.

,

Lias, S.G., Heller, S.R. and Milne, G.W.A., The NIST/EPA

data base of evaluated electron ionization mass spectra, The Wiley/NIST

registry of mass spectral data, John Wiley & Sons, Inc. (in press).

Chen, R. , Kafafi, S.A. and Stein, S.E., Reactivity of polycyclic aromatic

aryl radicals, J. Amer. Chem. Soc. (in press).

Clifton, C.L., Altstein, N. and Huie , R.E., Rate constant for the reaction

of NO2 with sulfur(IV) over the pH range 5.3-13, Environ. Sci. Technol.,

Vol. 22, p. 586 (1988)

Clifton, C.L. and Huie, R.E., Rate constants for hydrogen abstraction

reactions of the sulfate radical, S 04

_

, Alcohols, Int . J. Chem. Kinet.,

(submitted)

Cui, J.P., He, Y.Z. and Tsang, W. , Single pulse shock tube studies on the

stability of l-phenylbutene-2 , Energy and Fuel, Vol. 2, p. 614 (1988).

Cui, J.P., He, Y.Z. and Tsang, W. , Rate constants for hydrogen atom

attack on some chlorinated benzenes, J. Phys . Chem. (in press).

Cvetanovic R.J. and Singleton, D.L., Evaluated chemical kinetic data for the

reactions of atomic oxygen O(-^P) with sulfur containing compounds, J.

Phys. Chem. Ref. Data, Vol. 17 (in press).

Dagaut, P. , Wallington, T.J. and Kurylo, M.J., The temperature dependence

of the rate constant for the HO2 + CH3 O2 gas phase reaction, J. Phys.

Chem., Vol. 92, p. 3833 (1988).

Dagaut, P. , Wallington, T.J. and Kurylo, M.J., A flash photolysis kinetic

absorption spectroscopy study of the HO2 + C 2 H5 O 2 reaction over the

temperature range 228 - 380 K, J. Phys. Chem., Vol. 92, p. 3836 (1988).

Dagaut, P., Wallington, T.J., Liu, R. and Kurylo, M.J., The gas phase

reactions of hydroxyl radicals with a series of carboxylic acids over

the temperature range 240 - 440 K, Int. J. Chem. Kinet., Vol. 20, p. 331

(1988).

Dagaut, P., Wallington, T.J., Liu, R. and Kurylo, M.J., A kinetics

investigation of the gas phase reactions of OH radicals with cyclic

ketones and diones : mechanistic insights, J. Phys. Chem., Vol. 92, p.

4375 (1988).

Dagaut, P., Wallington, T.J. and Kurylo, M.J., The UV absorption spectra

and kinetics of the self reactions of CH2 CIO2 and CH2 FO 2 radicals in the

gas phase, Int. J. Chem. Kinet., Vol. 20, p. 815 (1988).

43
Dagaut, P. , Wallington, T.J. and Braun, W. , Energy transfer from

vibrationally excited SF^ to benzene, hexafluorobenzene , fluorobenzene

and toluene, J. Photochem. Photobiol., A: Chem. (in press)

Deakyne , C.A. and Mautner, M.M. , Methyl cation affinities of N, 0, and CC

lone pair donors, J. Am. Chem. Soc. (in press).

DeMore, W.B., Molin, M.J., Sander, S.P., Golden, D.M.

,

Hampson, R.F., Kurylo,

M.J., Howard, C.J. and Ravishankara , A.R.

,

Chemical kinetics and

photochemical data for the use in stratospheric modeling, Evaluation No.

8, NASA Panel for Data Evaluation, JPL Publication, Vol. 87, p. 41, Jet

Propulsion Laboratory, Pasadena, CA (1987).

Dirksen, M.L., Blakely, W.F., Holwitt, E. and Dizdaroglu, M. , Effect of DNA

conformation on the hydroxyl radical- induced formation of 8 , 5 ' -cyclopur

ine 2 ' -deoxyribonucleoside residues in DNA, Int. J. Radiat. Biol., Vol.

54, p. 195 (1988).

Dizdaroglu, M. , Measurement and significance of free radical damage to DNA in

Free Radicals: Methodology and Concepts, eds .

,

C. Rice -Evans and B.

Halliwell, pp . 123-138, Richelieu Press, London (1988).

Dizdaroglu, M. , Chemical determination of oxidative damage to DNA, in

Handbook of Biomedicine of Free Radicals and Antioxidants, ed.

,

J.

Miguel, H. Weber and A. Quintanilha, CRC Press, Boca Raton, FL (in

press)

Dizdaroglu, M. , The purification of polypeptide samples by ion-exchange

chromatography on silica-based supports, in High-Performance Liquid

Chromatography in Biotechnology, ed. , W.S. Hancock, John S. Wiley, New

York, NY (in press).

Dizdaroglu, M. and Gajewski, E. , Selected-ion mass spectrometry:

assays of oxidative damage to DNA, Methods in Enzymology (in press).

Dizdaroglu, M. , Gajewski, E. , Reddy, P. and Margolis, S.A., Structure of a

hydroxyl radical- induced DNA-protein crosslink involving thymine and

tyrosine in nucleohistone , Biochem. (submitted).

Fahr, A. , Laufer, A.H. and Braun, W. , Phosphor film characterization

measurements in the V.U.V. using a multichannel detector, Appl. Opt.,

Vol. 26, p. 3428 (1987).

Fahr, A. and Laufer, A.H.

,

An ultraviolet absorption of vinyl radical and

reaction with oxygen, J. Phys . Chem. (in press).

Fahr, A. and Stein, S.E., Reactions of vinyl and phenyl radicals with ethyne,

ethene and benzene, Int. Combust. Symp . (Proc.), Seattle, WA (1988).

Fahr, A. and Stein, S.E., Gas phase reactions of phenyl radicals with

aromatic molecules, J. Phys. Chem., Vol. 92, p. 4951 (1988).

44
Gajewski, E., Fuciarelli, A. F. and Dizdaroglu, M. , Structure of hydroxyl

radical- induced DNA-protein crosslinks in calf thymus nucleohistone in

vitro . Int. J. Radiat. Biol., Vol. 54, p. 445 (1988).

Green, P., Green, W.A. , Harriman, A., Richoux, M.C. and Neta, P.,

The dehydrogenation of ethanol in dilute aqueous solution photosensitized by benzophenones , J. Chem. Soc. Faraday Trans., Vol. 2, No. 84,

p. 2109 (1988).

Hampson, R.F., et al .

,

Chemical kinetics and photochemical data for use in

stratospheric modeling. Evaluation No. 8, NASA Panel for Data

Evaluation, Vol. 87, p. 41 (1987), Jet Propulsion Laboratory, Pasadena,

CA.

Hampson, R.F., et. al . Evaluated kinetic and photochemical data for

atmospheric chemistry: supplement III, IUPAC sub-committee on gas

kinetic data evaluation for atmospheric chemistry, J. Phys . Chem. Ref.

Data (submitted)

Hampson, R.F. and Mallard, W.G., Data bases for atmospheric chemistry,

Proc. of the 11th Int. CODATA Conf .

,

Hemisphere Pub. Corp .

,

Washington,

DC ( in press)

Harriman, A., Millward, G.R., Neta, P., Richoux, M.C. and Thomas, J.M.,

Interfacial electron transfer reactions between Pt colloids and reducing

radicals in aqueous solution, J. Phys. Chem., Vol. 92, p. 1286 (1988).

Harriman, A., Nahor, G.S., Mosseri, S. and Neta, P., Iridium oxide

hydrosols as catalysts for the decay of zinc porphyrin radical cations

in water, J. Chem. Soc. Faraday Trans., Vol. 1, No. 84, p. 2821 (1988).

Harriman, A., Richoux, M.C., Christensen, P.A., Mosseri, S. and Neta, P.,

Redox reactions with colloidal metal oxides, J. Chem. Soc. Faraday

Trans., Vol. 1, No. 83, p. 3001 (1987).

He, Y.Z., Cui , J.P., Mallard W.G. and Tsang, W. , Rate constants and

mechanism for the reaction of hydrogen atoms with aniline, J. Phys.

Chem., Vol. 92, p. 1510 (1988).

He, Y.Z., Cui, J.P., Mallard W.G. and Tsang, W. , Homogeneous gas phase

formation and destruction of anthranil from o-nitrotoluene decomposition, J. Amer. Chem. Soc., Vol. 110, p. 3754 (1988).

He, Y.Z., Mallard, W.G. and Tsang, W. , Mechanism and rates of hydrogen atom

attack on phenol, J. Phys. Chem., Vol. 92, p. 2196 (1988).

Herron, J.T. and Tsang, W. , Combustion Chemistry, Chem. Eng. News, Vol. 60,

p. 3 (1987).

Herron, J.T. and Tsang, W. , Formation and stability of SF5 and S2F10, in

Gaseous Dielectrics V, L.G. Christophorou, ed.

,

Pergamon Press, New

York, NY, p. 199 (1987).

45
Herron, J.T., S 2 F30 formation in computer simulation studies of the breakdown

of SFg, IEEE Transactions on Electrical Insulation, EI-22, p. 523

(1987).

Herron, J.T., Thermochemistry of sulfoxides and sulfones, in The Chemistry of

Sulfoxides and Sulfones, S. Patai, Z. Rappoport and C.J.M. Sterling,

eds., Wiley, New York, NY, p. 749 (1987).

Herron, J.T., A critical review of the kinetics of the reactions of atomic

3

oxygen OP with saturated organic compounds, J. Phys . Chem. Ref. Data,

Vol. 17 (in press).

Herron, J.T., Thermochemical data on the gas phase compounds of sulfur,

fluorine, oxygen and hydrogen related to pyrolysis and oxidation of

sulfur hexafluoride, J. Phys. Chem. Ref. Data, Vol. 16, p. 1 (1987).

Hudgens, J.W., Progress in resonance enhanced multiphoton ionization

spectroscopy of transient free radicals, in Advances in Multi-photon

Processes and Spectroscopy, S.H. Lin, ed.

,

Vol. 4, pp . 171-296 (1988),

World Scientific Publishing Co., Singapore.

Hudgens, J.W., Johnson, R.D., III and Tsai, B.P., Resonance enhanced

multiphoton ionization detection of GeF and GeCl radicals, Proc . of the

4th Int. Symp . on Resonance Ionization Spectroscopy and Its

Applications, p. 125 (1988), IOP Publishing, Bristol, UK.

Hudgens, J.W., Johnson, R.D., III and Tsai, B.P., Two photon resonance

enhanced multiphoton ionization detection and spectroscopy of gas phase

germyl (GeH3 ) radicals, Proc. of the Fourth Int. Laser Sci. Conf .

,

Atlanta, GA, Oct. 2-6, 1988 (in press).

Hudgens, J.W. and Long, G.R., Resonance enhanced multiphoton ionization

spectroscopy of CHCI 2 and CDCI 2 , Proc. of the Third Int. Laser Sci.

Conf., Atlantic City, NJ , Nov. 1-5, 1987 (in press).

Huie , R.E., Free radical chemistry of aqueous -phase SO 2 in Acid Rain:

Scientific and Technical Advances, R. Perry, R.M. Harrison, J.N.B. Bell

and J.N. Lester, eds., Selper Ltd., London (1987).

Huie, R.E., Brault, D. and Neta, P., Rate constants for one-electron

oxidation by the CF3 O 2 , CCI 3 O2 , and CBr 302 radicals in aqueous

solutions. Chem. -Biol. Interact., Vol. 62, p. 227 (1987).

Huie, R.E. and Clifton, C.L., Rate constants for hydrogen abstraction

reactions of the sulfate radical, SO4

"

, alkanes and ethers, Int. J.

Chem. Kinet. (submitted).

Huie, R.E., Clifton, C.L. and Altstein, N. , A pulse radiolysis and flash

photolysis study of the radicals SO2

", SO3’, SO4" , and SO5", Radiat.

Phys. Chem. (in press).

46
Huie , R.E., Clifton, C.L., Altstein, N. and Ouellette, P.A., Rate constants

for the reactions of O2

" and HO2 with HSO3

", S 03 ^" and S 05 ~, J. Geophys

Res. (submitted).

Jackson, J.H., Gajewski, E. , Fuciarelli, A.F., Schraufs tatter , I.U.,

Hyslop, P.A., Cochrane, C.G. and Dizdaroglu, M. , Damage to the bases in

DNA by stimulated neutrophils, J. Clin. Invest, (in press).

Johnson, R.D., III, Fang E. and Hudgens, J.W., Multiphoton ionization

spectroscopy of SiCl radicals between 430 and 520 nm, J. Phys . Chem.

,

Vol . 92, p. 3880 (1988).

Johnson, R.D., III and Hudgens, J.W., Two photon resonance enhanced

ionization spectra of the 3p7r D ^IIr

(v' = 0,1,2) <-«- X ^II r (v" = 0) bands

of the CF radical between 355 and 385 nm, J. Phys. Chem., Vol. 91, p.

6189 (1987).

Johnson, R.D., III and Hudgens, J.W., A new electronic spectrum of the SiH3

radical observed by multiphoton ionization spectroscopy, Chem. Phys.

Lett., Vol. 141, p. 163 (1987).

Johnson, R.D., III and Hudgens, J.W., Resonance enhanced multiphoton

ionization spectroscopy of SiCl between 400 and 500 nm, Proc. of the

Third Int. Laser Sci. Conf .

,

Atlantic City, NJ , Nov. 1-5, 1987 (in

press)

Johnson, R.D.

,

III, Tsai, B.P. and Hudgens, J.W., Spectrum (310 to 360 nm)

and ionization potential of the silyl radical, Proc. of the Fourth Int.

Laser Sci. Conf., Atlanta, GA, Oct. 2-6, 1988 (in press).

Johnson, R.D., III, Tsai, B.P. and Hudgens, J.W., A new electronic spectrum

of the SiH3 radical observed using multiphoton ionization spectroscopy,

Proc. of the 4th Int. Symp . on Resonance Ionization Spectroscopy and Its

Applications, IOP Publishing, Bristol, UK (in press).

Johnson, R.D., III, Tsai, B.P. and Hudgens, J.W., The electronic spectrum of

the GeH3 radical, J. Chem. Phys., Vol. 89, p. 4558 (1988).

Johnson, R.D., III, Tsai, B.P. and Hudgens, J.W., Resonance enhanced

multiphoton ionization spectra of the GeF and GeCl radicals between 400

and 500 nm, J. Chem. Phys., Vol. 89, p. 6064 (1988).

Kafafi, S.A. and Hudgens, J.W., Ab initio calculations of the electronic

structure and vibrational frequencies of the dichloromethyl radical and

cation, J. Phys. Chem. (in press).

Kafafi, S.A., Martinez, R.I. and Herron, J.T., Chemistry of dioxymethylenes

and dioxiranes, in Molecular Structure and Energetics, J.L. Liebman and

A. Greenberg, eds .

,

VCH Publishers, Deerfield Beach, FL (in press).

47
Kafafi, S.A. and Lowe, J.P., Substitutional effects on polymer band gaps,

in Molecular Structure and Energetics, J.F. Liebman and A. Greenberg,

eds .

,

VCH Publishers Inc., Deerfield Beach, FL (in press).

Kafafi, S.A., Mautner, M. and Liebman, J.F., The proton affinities of

styrene, trans-B-methylstyrene and indene : a theoretical and

experimental study, Struct. Chem. (in press).

Karam, L.R.

,

Dizdaroglu, M. and Simic, M.G., H atom abstraction from the

sugar moiety by thymine radicals in oligo- and polythymidylic acid,

Radiat. Res. (in press).

Kurylo, M.J., Wallington, T.J. and Dagaut, P., Gas phase studies of

substituted methyl peroxy radicals: the UV absorption spectrum and

self -reaction kinetics of CH3 OCH2 O 2 ; the reaction of CF2 CIO2 with Cl

Atoms, J. Photochem. Photobiol., A: Chem. (in press)

Lias, S.G. and Ausloos, P.J., Structure and heats of formation of C4H-j +

ions in the gas phase, Int. J. Mass Spectrom. Ion Proc . , Vol. 81, p. 165

(1987)

Lias, S.G., Bartmess, J.E., Liebman, J.F., Holmes, J.L., Levin, R.D.

and Mallard, W.G., Gas-phase ion and neutral thermochemistry, J. Phys

Chem. Ref. Data, Vol. 17, Suppl. No. 1 (1988).

Lias, S.G., Numeric data bases for use in analytical chemistry, NIST J. Res.

( in press)

Liu, R. , Wallington, T.J., Dagaut, P. and Kurylo, M.J., Group reactivities

in the gas phase reactions of hydroxyl radicals with ethers, Chinese J.

Phys. Chem. (in press).

Long, G.R. and Hudgens, J.W., Resonance enhanced multiphoton ionization

spectroscopy of CHCI 2 and CDCI 2 , J. Phys. Chem., Vol. 91, p. 5870

(1987)

Manka, M.L. and Stein, S.E., Rate constants for hydrogen abstraction by

resonance stabilized radicals in high temperature liquids, Int. J. Chem.

Kinet., Vol 19, p. 943 (1987).

Margolis, S.A., Coxon, B., Gajewski, E. and Dizdaroglu, M. , Structure of a

hydroxyl radical- induced crosslink of thymine and tyrosine, Biochem.

,

Vol. 27, p. 6353 (1988).

Martinez, R.I., The NIST triple quadrupole tandem mass spectrometer, Rev.

Sci. Instrum, (submitted).

Martinez, R.I., Instrument- independent MS/MS data base for XQQ instruments:

the dynamical prerequisites, Rapid Commun. Mass Spectrom., Vol. 2, p. 8

(1988)

48
Martinez, R.I. and Ganguli, B. , Reaction- induced mass discrimination in XQQ

instruments: absolute cross-sections for N2

++SFg -N2+SFX

+ (x = 1-5),

Rapid Commun. Mass Spectrom. , Vol. 2, p. 41 (1988).

Martinez, R.I. and Dheandhanoo, S., Absolute Cross-Section Measurements in

XQQ Instruments: Ar+ (N2

, Ar)N2

+

, Xnt. J. Mass Spectrom. Ion Proc . , Vol.

84 (1988).

Martinez, R.I. and J.T. Herron, Stopped- flow studies of the mechanisms of

ozone -alkene reactions in the gas phase: trans -2 -Butene , J. Phys . Chem.

Vol. 92, p. 4644 (1988)

Martinez, R.I., Absolute cross-section measurements in XQQ instruments:

the NBS round robin, J. Res. Nat. Bur. Stand. (US), Vol. 93, p. 431

(1988)

Martinez, R.I., Dynamical prerequisites for generic CAD spectra, ESL-TR88 -XX, Engineering and Services Laboratory, Air Force Engineering and

Services Center, Tyndall AFB, FL, 1988 (submitted).

Meot-Ner (Mautner) , M. , Cybulski, S.M., Scheiner, S. and Liebman, J.F., Is

CN"significantly unisotropic? Comparison of CN vs. Cl : clustering

with HCN and condensed-phase thermochemistry, J. Phys. Chem., Vol. 92,

p. 2738 (1988).

Meot-Ner (Mautner) , M. , Models for strong interactions in proteins and

enzymes. 1. Enhanced acidities of principal biological hydrogen donors,

J. Am. Chem. Soc., Vol. 110, p. 3071 (1988).

Meot-Ner (Mautner) , M. , Models for strong interactions in proteins and

enzymes. 2. Interactions of ions with the peptide link and with

imidazole, J. Am. Chem. Soc., Vol. 110, p. 3075 (1988).

Meot-Ner (Mautner), M. , The ionic hydrogen bond and ion solvation. 6 . Interaction energies, solvation of the acetate with org. matec.

,

comparison of CH3 COO with Cl , CN and SH , J . Am. Chem. Soc., Vol. 110,

p. 3854 (1988).

Meot-Ner (Mautner), M. , The ionic hydrogen bond and ion solvation. 7.

Interaction energies of carbonions with solvent molecules, J. Am. Chem.

Soc., Vol. 110, p. 3858 (1988).

Meot-Ner (Mautner), M. and Karpas , Z., Alkyl transfer reactions between

protonated alcohols and ethers. Gas -phase alkylation of formaldehyde, J.

Phys. Chem. (submitted).

Meot-Ner (Mautner), M. and Speller, C.V., Multicomponent cluster ions. 3.

Comparative stabilities of cationic and anionic hydrogen bonded

networks. Mixed clusters of water and hydrogen cyanide, J. Phys. Chem.

(submitted)

49
Meot-Ner (Mautner) , M. and Tsang, W. , Entropy driven proton transfer

reactions, J. Am. Chem. Soc. (submitted).

Meot-Ner (Mautner), M. and Kafafi, S.A., Carbon acidities of aromatic

compounds, J. Am. Chem. Soc., Vol. 110, p. 6297 (1988).

Meot-Ner (Mautner), M. , Entropy barriers to proton transfer: rates and

temperature coefficients in hindered amines and pyridines, J. Am. Chem.

Soc. (submitted).

Meot-Ner (Mautner), M. , Ion chemistry of ferrocene: thermochemistry of

ionisation and protonation, slow and entropy-driven proton transfer

kinetics, J. Am. Chem. Soc. (submitted).

Meot-Ner (Mautner), M. , Unimolecular thermal decomposition of ions:

protonated ethanol and diethyl ether, Int. J. Mass Spectrom. Ionic Proc

(submitted)

Mosseri, S., Neta, P., Hambright, P., Sabry, D.Y. and Harriman, A., Redox

reactions of osmium porphyrins, J. Chem. Soc., Dalton Trans, (in press).

Mosseri, S., Neta, P. and Hambright, P., Radiolytic studies of the redox

reactions of ruthenium porphyrins, J. Phys . Chem. (in press).

Mosseri, S., Neta, P. and Meisel, D., The mechanism of cyanide release in

the radiolysis of acetonitrile, formation and decay of the cyanomethylperoxyl radical, Radiat. Phys. Chem. (submitted).

Nahor, G.S., Formation and decay of zinc tetrakis (N-methyl-4-pyridinio)

porphyrin 7r-radical cation in aqueous solutions containing azide ions

and a polyelectrolyte, J. Phys. Chem., Vol. 92, p. 4359 (1988).

Nahor, G.S., The decay of a zinc porphyrin 7r-radical cation in the presence

of a negative polyelectrolyte and iridium(IV) oxides, a pulse radiolytic

study, Langmuir (submitted).

Nahor, G.S., Mosseri, S., Neta, P. and Harriman, A., Polyelectrolyte

stabilized metal oxide hydrosols as catalysts for the photooxidation of

water by zinc porphyrins, J. Phys. Chem., Vol. 92, p. 4499 (1988).

Nelsen, S.F., Rumack, D.T. and Meot-Ner (Mautner), M. , Ionization energies of

alkylhydrazines , J. Am. Chem. Soc., Vol. 110 (in press).

Nelsen, S.F., Rumack, D.T., Sieck, L.W. and Meot-Ner (Mautner), M. , Proton

affinities and basicities of alkylhydrazines, J. Am. Chem. Soc., Vol.

110, p. 6303 (1988).

Neta, P., Reactions of radicals with biologically important molecules, in

Chemical Kinetics of Small Organic Radicals, Z.B. Alfassi, ed.

,

Vol. IV,

p. 161, CRC Press, Boca Raton, FL (1988).

50
Neta, P. , Radiation chemistry of quinonoid compounds, in The Chemistry of

the Quinonoid Compounds, S. Patai and Z. Rappoport, eds . , Chap. 14, p.

879, Wiley, New York, NY (1988).

Neta, P. and Dizdaroglu, M. , Radiation chemistry of enones , in The Chemistry

of Enones, S. Patai and Z. Rappoport, eds., Wiley, New York, NY (in

press)

Neta, P. and Harriman, A. , Pulse radiolysis studies of organic electron

transfer reactions, in Photoinduced Electron Transfer, M.A. Fox and M.

Chanon, eds., Elsevier (in press).

Neta, P., Huie, R.E., Mosseri, W. , Shastri, L.V.

,

Mittal, J.P., Maruthamuthu,

P. and S. Steenken, Rate constants for reduction of substituted methyl

peroxyl radicals by ascorbate ions and TMPD, J. Phys . Chem. (submitted).

Neta, P. , Huie, R.E. and Ross, A.B., Rate constants for reactions of

organic radicals in aqueous solution, J. Phys. Chem. Ref. Data, Vol. 17,

p. 1027 (1988).

Neta, P. and Ross, A.B., Representative rate constants for radical reactions

of biologically important molecules, in Chemical Kinetics of Small

Organic Radicals, Z.B. Alfassi, ed.

,

Vol. IV, p. 187 (1988), CRC Press,

Boca Raton, FL.

Ozturk, F. , Moini

and Ausloos

,

diacetylene

,

M. , Brill, F.W.

,

Eyler, J.R., Buckley, T.J., Lias, S.G.

P.J., Reactions of C 5H5

+ and C 5 H3+ ions with acetylene and

J. Phys. Chem. (submitted).

Senthilnathan, V.P. and Stein, S.E., Mechanisms of condensation of biaryl

hydrocarbons, J. Organ. Chem. (in press).

Sieck, L.W. and Van Brunt, R.J., Rate constants for F transfer from SF g to

fluorinated gases and SO 2 , temperature dependence and implications for

electrical discharges in SF5 , J. Phys. Chem., Vol. 92, p. 708 (1988).

Sieck, L.W. and Meot-Ner (Mautner) , M. , Yhr ionic hydrogen bond and ion

solvation. 9. RS . . .HOR bond strengths, correlation with acidities, J.

Phys. Chem. (in press).

Stein, S.E. and Brown, R.L., Pi-electron properties of large condensed

polyaromatic hydrocarbons, J. Am. Chem. Soc., Vol. 109, No. 12, p. 3721

(1987) .

Stein, S.E., Griffith, L.L.

,

Billmers, R. and Chen, R.H.

,

Pyrocondensation

of anthracene, J. Org. Chem., Vol. 52, p. 1582 (1987).

Stein, S.E. and Brown, R.L.

,

Pathways to graphite: Properties of very large

polybenzenoid hydrocarbons, molecular structure and reactivity, Leibman

and Greenberg, eds., VCH Publishers, New York, NY, pp . 37-66 (1987).

51
Stein, S.E., Brown, R.L. and Kafafi, S.A., Fundamental chemistry of

uncatalyzed coal gasification, Proc . 1987 Int. Conf. on Coal Science,

Elsevier Press, The Netherlands, pp. 495-500 (1987).

Stein, S.E. and Suryan, M.M.

,

Initial steps in lignin thermolysis: model

compound studies of substituted anisoles, Proc. 1987 Int. Conf. on Coal

Science, Elsevier Press, The Netherlands, pp . 749-756 (1987).

Stein, S.E. and Suryan, M.M.

,

Homolysis of substituted anisoles: substitutent

effects on phenoxyl radical stabilities, Proc. Oxygen Radicals Conf. (in

press)

Suryan, M. , Kafafi, S.A. and Stein, S.E., The thermal decomposition of

hydroxy-and methoxy- anisoles, J. Am. Chem. Soc. (in press).

Suryan, M.M.

,

Kafafi, S.A. and Stein, S.E., Dissociation of substituted

anisoles: substituent effects on bond strengths, J. Am. Chem. Soc. (in

press)

Suryan, M.M. and Stein, S.E., Stabilities of substituted benzyl radicals:

dissociation rates of amino, hydroxy and cyano ethylbenzenes, J. Phys

Chem. (submitted)

Suryan, M.M.

,

Kafafi, S.A. and Stein, S.E., The thermal decomposition of

hydroxy and methoxy substituted anisoles, J. Am. Chem. Soc. (in press).

Suryan, M.M.

,

Kafafi, S.A. and Stein, S.E., Substitutent effects on phenoxyl

radical stabilities, Proc. Oxygen Radicals Conf. (in press).

Tsai, B.P., Johnson, R.D., III and Hudgens, J.W., Resonance enhanced

multiphoton ionization spectroscopy of 2-Butene-l-yl (C4H7 ) between 455-

485 nm, Proc. of the 4th Int. Symp . on Resonance Ionization Spectroscopy

and Its Applications, IOP Publishing, Bristol, UK (in press).

Tsang, W. , Chemical kinetic data base for combustion chemistry, Part 2.

Methanol, J. Phys. Chem. Ref. Data, Vol. 16, p. 471 (1987).

Tsang, W. , He, Y.Z., Mallard, W.G. and Cui , J.P., Single pulse shock tube

study of the reactions of hydrocarbons with aromatics, IV.

Chlortoluenes , Proc. of the 16th Int. Symp. on Shock Tubes and Waves,

VCH Publishers, New York, NY, p. 467 (1988).

Tsang, W. , Chemical kinetic data base for combustion chemistry, Part III.

Propane, J. Phys. Chem. Ref. Data, Vol. 17, p. 887 (1988).

Tsang, W. , Unimolecular processes over extended temperature and pressure

ranges, Combustion and Flame (in press).

Tsang, W. , Chemical kinetic data base for combustion chemistry, Part IV.

Isobutane, J. Phys. Chem. Ref. Data (in press).

52
Tsang, W. , Mallard W.G. and Herron, J.T., Progress in the development of a

chemical kinetic data base for combustion chemistry, Proc. of the 11th

CODATA Conference (in press).

Tsang, W. and Walker, J.A., High temperature reactions of hydrogen atom

reactions with isobutene, Proc. 22nd Symp . on Combustion (in press).

Van Brunt, R. J., Herron, J.T. and Fenimore , C., Corona induced

decomposition of dielectric gases, in Gaseous Dielectrics V, L.G.

Christophorou, ed. , p. 163 (1987), Pergamon Press, New York, NY.

Van Brunt, R. J., Sieck, L.W.

,

Sauuers, I. and Siddagangappa , M.C., Transfer

of F in the reaction of SF 5 with SOF4 , implications for SOF4 production

in corona discharges, Plasma Chem. Plasma Proc., Vol. 8 , p. 225 (1988).

Wallington, T.J., Scheer, M.D. and Braun, W. , V > R,T energy transfer

processes in vibrationally excited pentafluorobenzene using a Hg tracer

absorption method, Chem. Phys . Lett., Vol. 138, p. 538 (1987).

Wallington, T.J., Braun, W. , Beck, K.M. and Gordon, R.J., Comparison of the

optoacoustic and Hg tracer methods for the study of energy- transfer

processes in gas mixtures, J. Phys. Chem. (in press).

Wallington, T.J., Dagaut, P. and Braun, W. , Energy transfer from

vibrationally excited pentafluorobenzene to helium, xenon and water

vapor, Chem. Phys. Lett., Vol. 144, p. 299 (1988).

Wallington, T.J., Liu, R. , Dagaut, P. and Kurylo, M.J., The gas phase

reactions of hydroxyl radicals with a series of aliphatic ethers over

the temperature range 240 - 440 K, Int. J. Chem. Kinet., Vol. 20, p. 41

(1988)

Wallington, T.J., Dagaut, P., Liu, R. and Kurylo, M.J., Flash photolysis

resonance fluorescence investigation of the gas phase reactions of OH

radicals with a series of aliphatic esters over the temperature range

240 - 440 K, Int. J. Chem. Kinet., Vol. 20, p. 177 (1988).

Wallington, T.J., Dagaut, P. and Kurylo, M.J., Measurements of the gas

phase UV absorption spectrum of C 2H5 O2 radicals and of the temperature

dependence of the rate constant for their self reaction, J. Photochem.

Photobiol., A: Chem., Vol. 42, p. 173 (1988).

Wallington, T.J., Dagaut, P., Liu, R. and Kurylo, M.J., The gas phase

reactions of hydroxyl radicals with the fuel additives methyl- t -butyl

ether and t-butyl alcohol over the temperature range 240 - 440 K,

Environ. Sci. Tech., Vol. 22, p. 842 (1988).

Wallington, T.J., Dagaut, P., Liu, R. and Kurylo, M.J., Rate constants for

the gas phase reactions of OH with C 5 through C 7 aliphatic alcohols and

ethers: predicted and experimental values, Int. J. Chem. Kinet., Vol.

20, p. 541 (1988).

53
Wallington, T.J., Dagaut, P. and Kurylo, M.J., A correlation between gas

phase and solution phase reactivities of OH radicals towards saturated

organic compounds, J. Phys . Chem. , Vol. 92, p. 5024 (1988).

Wallington, T.J., Dagaut, P. and Kurylo, M.J., A flash photolysis kinetic

spectroscopy investigation of the absorption spectrum and self -reaction

of C 2 H4CIO2 radicals in the gas phase, Chem. Phys. Lett., Vol. 146, p.

589 (1988).

Watson, R.T., Prather, M.J. and Kurylo, M.J., Present state of knowledge

of the upper atmosphere, 1988: an assessment report, NASA Publ. 1208

(June 1988)

Westley, F. , Herron, J.T. and Cvetanovic, R.J., Compilation of chemical

kinetic data for combustion chemistry. Part 1. Non-aromatic C, H, 0, N,

and S containing compounds (1971-1982), NSRDS-NBS 73, Part 1, U.S. Gov.

Printing Office, Washington, DC 20402 (1987).

Westley, F. , Cvetanovic, R.J. and Herron, J.T., Compilation of chemical

kinetic data for combustion chemistry, Part 2. Non-aromatic C, H, 0, N,

and S containing compounds (1983), NSRDS-NBS 73, Part 2, U.S. Gov.

Printing Office, Washington, DC 20402 (1987).

54
TECHNICAL ACTIVITIES

OF THE

CHEMICAL ENGINEERING SCIENCE DIVISION

L.L. Sparks, Acting Chief

1. INTRODUCTION

Reliable engineering data and well -documented characterization of

process mechanisms form the basis for design and operation of plants and

facilities in the chemical, biochemical, petrochemical, petroleum, gas and

other processing industries. State-of-the-art information in these areas

enables U.S. industry to compete effectively in the world marketplace.

Increased emphasis on environmental effects has created a growing need for

alternative processes which operate with closer tolerances, emphasize higher

yields, and stress internal recycling made possible by separations. The

development of accurate process models, for the design of the newer and less

conventional plants and to improve conventional ones, requires reliable and

well documented process characteristics as well as accurate models for the

transport operations and dynamics represented within these industrial

processes. Activities needed to address these chemical process industry

needs are laboratory determination of elemental process mechanisms and

characteristics, theoretically based predictive models for subprocesses

involving and using complex fluids and solids, and analysis of the dynamics

of engineering systems.

In addition to contributions directly related to process design and

operation, and concomitant environmental compatibility, the work of the

Division also involves many areas of research done in support of other

segments of the private sector and other government agencies. This

externally supported research constitutes a major part of the planned effort

in achieving the goals of the Division. Problems being addressed are, in

general, directed to specific needs of industry, trade associations, NASA,

DOD, etc. The research results, however, are applicable to and available for

a broad spectrum of scientific, industrial, and academic needs. The data and

procedures for accurate and verifiable custody transfer of chemicals and

fuels, heat transfer data and models for the National Aerospace Plane, basic

studies of combustion in oxidizing atmospheres, data and models for the

properties of advanced materials, and refrigeration techniques are examples

of basic and applied research being done in support of National programs.

In all areas that relate to the research of the CCT-Gaithersburg

Divisions, close collaborative interactions have been developed. There is

strong collaboration with the Thermophysics Division to integrate fluid and

solids properties with process mechanisms and models, and with the Chemical

Process Metrology Division in flow research. These collaborations include

several joint projects sponsored by other agencies, and there are ongoing

efforts to expand our synergistic efforts in all areas of mutual interest.

55
One of the primary focuses of research in the Division is on industries

related to the rapidly expanding field of biotechnology. For the most part,

a thorough and quantitative understanding of the behavior of separation

factors and transport mechanisms of these new biochemical systems does not

presently exist, especially as these relate to products created by genetic

engineering. The complexity of the phenomena involved and the vast array of

products and processes encountered preclude the possibility of a purely

experimental or correlative approach. The approach must be one which

includes experiment, theory, and evaluation so as to yield accurate process

and related transport phenomena, and which facilitates the development of

generic predictive models that are applicable to a broad range of biosubstances. The theoretical effort will break new ground in understanding

separations at the molecular level, phase equilibria involving multiple

phases, biological system behavior, heat and mass transfer, and other unit

operations. Experimental efforts include membrane separation of amino acids

and two-phase aqueous extraction. Other extensions of the state of the art

in separation technology are anticipated in the Division's long-range plans.

The research of the Division addresses scientific issues of national

interest in which NIST expertise and its impartial position are critical to

an acceptable resolution, as with the highly accurate measurement and

modeling of the flow of fluids such as natural gas, selected fluid mixtures,

and cryogens . Standard Reference Materials, Standard Test Methods, and

Standard Data are developed for selected thermal properties of solid

materials of interest to the chemical and related industries. The majority of

the effort is directed toward problems of the future. These include, but are

not restricted to: (1) transport processes related to the efficient use of

gases and liquids such as natural and synthesis gas, methanol, etc., for use

as chemical feedstocks and fuels; (2) utilization of more selective

separation processes; (3) bioproduct separation/purification technology

needed for large scale manufacture of biochemicals; and (4) new techniques

for management and disposal of potentially harmful chemical wastes. The

strategy is to perform basic research, generic to the science underlying the

chemical, biochemical, and petrochemical processing industries, which

requires the special role of NIST as an impartial national laboratory

excelling in measurements and their interpretation.

2. GOAL

The goal of the Division is to provide: (1) evaluated generic

engineering design data and elemental process engineering models,

(2) standard measurement procedures and test methods; and (3) predictive

techniques, correlations, computer codes, and underlying theories. These are

the tools needed by the chemical and related industries to design, control,

and develop new manufacturing processes and by other government agencies to

continue our Nation's leadership role in defense, space exploration, and

environmental issues.

The primary means of accomplishing this goal is by providing theoretically based modeling and predictive techniques, state-of-the-art measurement

techniques, and advanced understanding of elemental process mechanisms. The

approach is to conduct research on fundamental concepts, explore new ideas

56
and phenomena, and develop predictive models in synergism with experimental

programs. The endeavors nurture development of new processing techniques,

provide accurate models of transport phenomena, and lead to understanding of

advanced engineering concepts. An essential corollary of these efforts is

the critical evaluation and correlation of experimental measurement

techniques which lead to the development of voluntary standard measurement

practices and test methods.

3. GROUP FUNCTIONS

The research of the Division is organized into three technical groups:

Transport Processes, System Dynamics, and Properties of Solids.

• Transport Processes - S.K. Sikdar, Group Leader

The Transport Processes Group performs experimental, theoretical, and

mathematical modeling research in membrane processes, separation of gases and

biochemicals, heat transfer, reactor design, and transport processes in

microgravity. The products of these activities comprise design data, models,

and measurement techniques and methods , which will help chemical and

biochemical process industries to operate and control processes more

efficiently. Membrane separation research is focused on the purification of

acid gases by facilitated transport and on separating species from aqueous

and organic solutions. Heat transfer research addresses the need to

understand heat transfer properties of supercritical fluid mixtures near the

critical point. A major program on biochemical separation is directed toward

providing protein separation data and models for two-phase aqueous

extraction.

• System Dynamics - J.A. Brennan, Group Leader

The System Dynamics Group performs research to provide data, measurement

methodology, and thermodynamic criteria for the optimum application of

fundamental principles in physical process operations -- including flow

metrology at normal and extreme conditions, fluid management in normal and

low gravity, and mass and energy changes in multicomponent, multiphase

systems- -to support programs of other government agencies and industrial

trade organizations and to promote efficiency and measurement accuracy in the

chemical and related industries.

• Properties of Solids - L.L. Sparks, Group Leader

The experimental and analytical research of the Properties of Solids

Group is focused on the thermal properties (thermal conductivity, thermal

expansion, and heat capacity) of industrially important solids such as

foams, fibers, fiberboards, aggregates, metals, ceramics, composites, and

polymers. Programs are in place to study oxidation in the presence of oxygen

at high temperatures and pressures, efficiencies and new concepts of

cryogenic refrigeration, and concepts and evaluation of reactors to deal with

hazardous waste.

57
4. SELECTED PROJECT SUMMARIES

TRANSPORT PROCESSES GROUP

Membrane Separations with Reversible Chemical Interactions

Data. Mechanisms, and Modeling

J.J. Pellegrino, R.D. Nassimbene, M.K. Ko , B. Dutta,* M. Einert, S. Geer,

D. Lund, P. Marko , S.K. Sikdar

The use of membrane systems, as components in the separation of species

in gas and liquid streams, is an emerging technology. It offers fundamental

advantages in energy efficiency, selectivity, and process integration.

Chemical interactions between the separating species and the membrane phase

can be used to enhance the selectivity and productivity, as in facilitated

transport, or can be a cause of performance decline, as in ultrafiltration.

The fundamental characteristics of chemical interactions between solutes and

membrane phases are being studied for a number of applications, which

include: (1) selective separation of gases by immobilized liquid ionexchange membranes; (2) gas separations using inorganic membranes; (3)

macromolecule separations using ultrafiltration membranes; and, (4) small

organic molecule separations using polyelectrolyte and ion-exchange polymers.

The experimental program includes varying the chemical and structural

nature of the membrane phase and measuring single and multicomponent

permeation rates, sorption equilibria, and transport parameters.

Phenomenological modeling is being done to predict transport rates;

statistical models are being developed to predict effects of anisotropic pore

structures; molecular dynamic models are being investigated to study the

effect of phase transitions on separations in single pores, and unit

operations models are being developed to investigate integrated membrane

performance in system configurations.

GAS SEPARATION BY ION EXCHANGE MEMBRANES: We have successfully

developed membranes to selectively separate acid gases from H2 , with greater

selectivity than any prior reported systems. Using a gel perfluorosulfonic

acid (PFSA) membrane, obtained by swelling in glycerine, which contained the

carrier ethylene diamine, we obtained CO2 selectivity over H2 in the range

20-40. Using the same membrane, we obtained an H2

S separation factor

(over H2 ) of 95. Using hindered amines as carriers, we have also achieved

selectivity of H2 S over other acid gases, such as CO2

.

AMINO ACIDS ISOLATION/SEPARATION BY ION EXCHANGE MEMBRANES: We have

successfully cast a thin (10/im) film from solutions of the PFSA

polymer. We have also made a composite membrane by casting a thin PFSA

polymer layer on a microporous hydrophilic support. These thin membranes

have been tested for high amino acid permeation rates. Potential uses of

these membranes in amino acid isolation are being explored.

58
CHITIN-CHITOSAN MEMBRANES: We have cast this membrane from the chitinchitosan mixture. Flux data have been collected on selective separation of

aliphatic and aromatic amino acids. A gel form of this membrane has been

developed by selective crosslinking. The gel membrane has been found to

allow permeation of macromolecules.

^University of Calcutta, India

Heat and Mass Transfer to Supercritical Fluid Mixtures

M.C. Jones, G.R. Hardin, S.M. Selim (Colorado School of Mines)

The application of supercritical extraction on an industrial scale

requires a knowledge of the transport behavior of mixtures of supercritical

solvents and products in equipment for continuous processing such as

extraction vessels, heat exchangers, and fractionation columns. In this

work, such behavior is studied on a small scale; the approach is to apply

fundamental principles of transport mechanisms to precise measurements made

on mixtures with well -documented thermophysical properties.

Current emphasis is on measuring heat transfer coefficients accompanying

phase disengagement for mixtures of hydrocarbons in carbon dioxide . Such

measurements are necessarily made in the vicinity of a critical solution

point. To date, binary mixtures of n-decane/CC>2 and n-pentane/CC>2 have been

studied at mixture compositions on both sides of the lower critical solution

point. Visual observations show that unique hydrodynamics accompanies phase

disengagement and under some conditions gives rise to unexpectedly high heat

transfer coefficients. Similar behavior has been observed also in

disengagement of analogous liquid- liquid mixtures possessing lower consolute

points. A theoretical study of the possible role of thermocapillarity is

being undertaken, and an attempt is being made to elucidate the appropriate

correlating parameters.

Studies of Free Convection in Porous Media

by Residence Time Distributions

M.C. Jones, R.A. Perkins, J.D. Wolfe

The structure and dynamics of the global flow patterns of freeconvective flows in confined porous media is an important area of study for

many engineering applications. In this project, funded by the Department of

Energy, Office of Basic Energy Sciences, a new experimental approach is being

developed based on the principles of residence time distributions. Earlier

work has shown these to be sensitive indicators of such flow patterns.

On the experimental side, a new laser- fluorescence fiber optic probe of

superior sensitivity has been successfully developed. Arrays of such probes

are being used with fluorescent dyes to detect time-resolved flow patterns in

fluid- saturated containers filled with uniform glass spheres subject to freeconvective flows under precisely controlled conditions. In order to

interpret the experimental results, a computer code is under development in

59
which the progress of a tracer can be followed in three dimensions for

convecting patterns appropriate to a range of Rayleigh numbers and throughflow Peclet numbers. The role of nonlinear drag and of anisotropic

dispersion for both heat and mass transport is being studied. Unsteady flows

known to exist at high Rayleigh numbers are of particular interest.

Transient Heat Transfer to Liquid Hydrogen

B. Louie, W.G. Steward (Contractor)

Liquid hydrogen has been identified as an appropriate coolant for new

electrical conductor applications, including high-Tc superconductors. The

objective of this program was to determine the time of the onset of nucleate

boiling and the heat transfer behavior of liquid hydrogen at times less than

10"^ s when high heat fluxes were applied. An apparatus using square wave

and step power inputs to platinum foil resistors in liquid hydrogen has been

built and results have been obtained.

Heat fluxes ranging from 1 to 75 W/cm^ were applied. In general the

temperature at the metal surface increased until the onset of nucleate

boiling occurred at approximately 5 x 10"^ s. At this time the data

exhibited a peak in the temperature rise of 8 K, followed by stable, lower

temperatures indicative of steady state nucleate boiling. Immediately prior

to nucleate boiling, the trend in the data followed classical transient

conduction theory. The data at very short times, however, indicated earlier

transition periods which have not been reported for other cryogens . This

behavior may be explained by a nonuniform temperature distribution within the

platinum resistor.

Investigation of Alternative Non-Toxic Heat-Transfer

Fluids for Thermal -Control Systems in Spacecraft

P.J. Giarratano, J.F. Welch

NIST has been asked by the NASA Johnson Space Center to evaluate

existing pure substances, including commercially marketed heat transfer

fluids, for potential use in two-phase thermal -control systems in manned

spacecraft. Stringent constraints are imposed on candidate fluids. Among

these are nontoxicity, nonflammability, chemical stability, and good thermal

performance. Ultimately, the development of a new fluid meeting the above

constraints may be required. In view of the likely high cost, long term, and

complexity of such a development, an extensive and quantitative evaluation is

required to establish the need and/or specifications for the possible

development

The first phase of the NIST work (now complete) was to develop a

methodology for the quantitative evaluation of existing substances. A data

base of 850 chemical substances have been ranked and sorted according to this

methodology

60
The second phase of the study will extend the evaluation to commercially

available fluids.

NASA Space Station Fluid Physics /Dynamics

Facility Experiment Module

P.J. Giarratano

NASA is actively pursuing the development of modular, multi-user,

experimental facilities for microgravity experiments in the Space Station.

NIST has been funded to act in an advisory and consultative role in the

development of the specifications for the Fluid Physics module.

The initial effort (now complete) was to provide to the NASA Lewis

Research Center preliminary requirements for potential experiments in the

field of heat and mass transport in fluids.

The second objective of the work will be to aid NASA in the assessment

of their design concept once it is formulated. This will involve interaction

with the NASA Lewis Research Center design team and may consist of

modification or further definition of the earlier generated requirements.

Bioseparation by Two-Phase Extraction:

Partitioning Methods and Measurements

D.C. Szlag, K. Giuliano, D. Steward, K. Cole, J. Evans, P.W. Todd,

S.K. Sikdar

The objectives of this activity are to develop and evaluate novel,

scalable methods for the separation of biomolecules and bioparticles, to

measure and predict the separation of immiscible aqueous phases, and to

develop and evaluate novel, scalable methods of phase contacting and

demixing. The aqueous two -phase extraction technique is an important

alternative to chromatographic methods. The major goal of this program is,

therefore, to provide data and understanding necessary for the design of

industrial bioseparation processes using this technique.

A number of novel methods have been developed using inexpensive phase

forming polymers as solutes that drive phase separation. Affinity ligands

(also inexpensive) that enhance partition coefficients over 10- fold have been

developed. These have been applied to the purification of alcohol

dehydrogenase from a thermoanaerobe, an enzyme with significant industrial

potential. Procedures for measuring multiple partition coefficients using 2-

dimensional gel electrophoresis have been developed, and simpler procedures

that are not confounded by the presence of phase- forming polymers are being

sought. A chromatographic method for the rapid estimation of multiple

partition coefficients has been tested.

61
Modeling Aqueous Two-Phase Systems and Protein Partitioning

H. Cabezas (University of Arizona), D.C. Szlag, J. Evans

Parallel to the experimental efforts directed toward developing methods

and partitioning data bases on polymers and protein systems, we have

attempted to develop mathematical models capable of predicting phase diagrams

and protein partition in two-phase systems. We have succeeded in exploiting

T.L. Hill's formalism to derive equations which correctly predict

experimental phase -diagram data based on known properties of polyethylene

glycol (PEG) and dextran. Phase separation in PEG-salt systems and partition

coefficients of proteins are under continuing investigation. Laboratory

measurements of solution parameters are being performed in connection with

theoretical studies as a means of testing predictions.

Aqueous Two -Phase Contacting in Spray Columns

R. Rao (University of Bombay, India), S.K. Sikdar, D.C. Szlag

Mass transfer and demixing rates are important practical variables in

two -phase extraction, and pragmatic goals include the maximization of both.

We introduced the concept of dispersing one phase into the other in a spray

column and collected mass transfer and hold-up data on a two-meter column.

Contacting in a spray column obviates the need of a centrifuge to disengage

the phases. We continue to study drop dynamics, and the effect of multiple

stage operation on protein recovery.

It has been found that demixing rates can be enhanced substantially by

allowing phase separation to occur in a constant electric field.

Electrokinetic Separation Methods

P.W. Todd, R. Hertz, R. Rao (University of Bombay, India)

Free electrophoresis is another important alternative to chromatographic

methods, as it holds the potential to purify sample streams without

precipitation or adsorption. As in the case of two-phase extraction, it is

also applicable to bioparticles.

Cell separation: Studies on density- gradient and re-orienting density

gradient electrophoresis of bioparticles and cells have been initiated.

Isoelectric focusing: The replacement of ampholytes with buffers in

recycling isoelectric focusing, a process invented by M. Bier, can significantly enhance biomolecular activity and reduce costs at the pilot-plant

scale. Experiments using borate and citrate buffers indicate that it should

be possible to use these buffers for recycling isoelectric focusing in pilotplant operations and that the effectiveness of the method could be enhanced

by algorithmic control. Two-dimensional gel electrophoresis is a suitable

analytical method for analyzing results.

62
Single Crystal Growth bv Osmotic Dewatering

S.K. Sikdar, P.W. Todd, C. Walker, D. Lund

We have developed a generic method for growing single crystals using the

technique of osmotic dewatering, and tested the method by growing large

crystals of triglycine sulfate and lysozyme. In this method, a solution of

the candidate substance in a reverse osmosis (RO) membrane container is

contacted with an outer solution of a salt (such as NaCl or (NH4)2SC>4). Slow

but controllable dewatering takes place because of the difference in osmotic

pressures between the solutions. The nucleation point is approached slowly

and nucleation and subsequent growth take place at low supersaturation, thus

providing good single crystals. X-ray studies are being planned for these

crystals to ascertain quality. The method also has potential for inorganic

crystals

SYSTEM DYNAMICS GROUP

Slush Hydrogen Production and Characterization

R.O. Voth, P.R. Ludtke, D.E. Daney, J.D. Siegwarth, V.D. Arp, P. S torch

Future high performance aircraft will require high performance fuels

One candidate for fueling the National Aerospace Plane is a mixture of solid

and liquid (slush) hydrogen. At the present time, two production methods are

being investigated. One method uses an auger arrangement to scrape the

frozen hydrogen off a refrigerated surface, and the other method uses a

reduced pressure freeze -thaw procedure. Both production methods produce

slush that can be stored for extended periods and has acceptable flow

characteristics. In addition, the auger method of production includes a

study of the effect of auger size so that laboratory tests can be scaled to

full production requirements.

Optimum production, storage, and transfer of slush will be critical to

the successful use of this fuel. Therefore, experimental and analytical

studies will be conducted to determine the most efficient production

methodology. Coupled with these studies will be an investigation of the

instrumentation required for measuring pressure, temperature, flow rate,

density, and mass quality.

Metering of Natural Gas and Cryogenic Liquids

J.A. Brennan, S.E. McFaddin, C.F. Sindt, R.R. Wilson, J.D. Siegwarth

At the core of this work is a flow facility capable of providing

accurate and precise mass -based data for flowing cryogenic liquids and

ambient temperature gas. There are three projects currently under study.

The first is designed to provide substantial improvement in the metering of

natural gas by means of orifice and turbine type flowmeters. This multi-year

63
program, funded by the Gas Research Institute, includes an extensive series

of measurements on 7.6 cm and 10.2 cm diameter orifice meters. Also under

investigation are swirl phenomena, flow conditioning concepts, and pipe

roughness effects. The work in Boulder on gas flow is closely coordinated

with similar work on water flow in the Chemical Process Metrology Division.

The second area of flow research utilizes the flow facility to evaluate new

measurement techniques and to perform special tests on meters to provide

measurement traceability to NIST. These tests are performed with liquid

nitrogen. The third area of flow research is concerned with high velocity

flows (over 50 m/s) and utilizes water from a local hydroelectric plant since

such velocities are well beyond the range available in a laboratory. The

purpose of this work is to assist NASA in developing reliable flowmeters for

the Space Shuttle Propulsion System.

Process Thermodynamics

V.D. Arp, D.E. Daney, P.R. Ludtke , J.D. Siegwarth, R.O. Voth

This work is designed to provide engineering, principally cryogenic

engineering, expertise to other government agencies to solve or provide the

basis for solution of a variety of problems. Current research includes

(1) reviewing and evaluating thermodynamic modeling of cryogenic systems in

support of high energy physics experiments at the Los Alamos National

Laboratory, and (2) performing experiments and analyzing the fluid mechanics

and thermodynamics on the transfer and storage of large quantities of fluids

such as liquid hydrogen, oxygen, and superfluid helium with application to

fluid management in low gravity environments. The work in area (1) is

supported by the Department of Energy, and in area (2) by the National

Aeronautics and Space Administration.

PROPERTIES OF SOLIDS GROUP

Thermal Properties of Advanced Materials

J.B. Filla, D.L. Rule, D.R. Smith, L.L. Sparks

Ceramics, polymers, and composites which combine two or more advanced

materials continue to be developed as replacements for metals and plastics in

electronic components, high performance engines, and structures where

strength, weight, and thermal tolerance are critical. Research on these

materials has traditionally been in the areas of processing and mechanical

properties. Thermal properties must be known for advanced applications now

being contemplated, or, in some cases, actually incorporated in working

designs. The properties in question include thermal conductivity, thermal

expansion, heat capacity, and thermal diffusivity.

Five Group projects, intended to address these needs, were active in

FY88. They included (1) continued development of a steady- state thermal

conductivity apparatus to allow ceramics and ceramic composites to be studied

to 1270 K, (2) operation of a guarded-hot-plate thermal conductivity

64
apparatus to allow ceramic fiber insulation to be studied to 800 K, (3)

modification of an existing optical dilatometer, (4) operation of an

apparatus to study the steady- state conductivity of composites at low

temperatures, and (5) operation of a cut-bar apparatus to study the

conductivity of ceramics at moderate temperatures.

Crvocooler Studies

R. Radebaugh, I. Vazquez, P. S torch, K. McDermott, S. Geschwenter, J. Gary,*

J . Zimmerman4-

As part of an ongoing NASA/Ames contract, a second pulse tube

refrigerator was built using a small compressor of 25 cmj displacement.

Optimization studies for that system were completed, which led to a low

temperature of 67 K with 2 W refrigeration at 80 K. The optimum pulse tube

size was found to agree well with the theoretical model that was developed as

part of this work. Work on a two -stage pulse tube refrigerator began in

FY88. So far a temperature of 41 K has been reached, although optimization

studies of the system have just begun. The advantage of the pulse tube

refrigerator is that it is relatively efficient and it has no moving parts at

low temperatures. It has great potential for use in cooling infrared sensors

in satellite applications.

Under a Wright-Patterson Air Force Base contract, several regenerator

materials have been studied in the 8-25 K temperature range. These generators would be used in the lowest temperature stage of Stirling or Vuilleumier

cycle cryocoolers for cooling infrared sensors. The regenerators were tested

under realistic operating conditions. In most cases, the materials were in

the form of powder with a particle size of 227 nm. The materials studied

cover a wide range of heat capacities. They include brass, Pb + 5% Sb , GdRh,

and Nd. An interesting result found from these studies is that the low heat

capacity materials perform reasonably well as regenerators because of the

contribution of the void volume gas to the overall heat capacity.

The use of adsorbers as compressors for gas refrigeration systems

permits the elimination of a moving part. As part of a Kirtland AFB program

to develop these compressors for Joule -Thomson refrigerators, we are

providing the fundamental data on adsorption isotherms. Measurements in FY88

include N2 gas on 4 different carbon adsorbers. A new adsorption cell was

also constructed for measurements with methane, ethane, and carbon monoxide

up to a temperature of 300° C. Measurements of the thermal conductivity of

carbon with helium gas adsorbed was measured in the 6-300 K temperature

range. We discovered a new effect in which the adsorbed film transports a

very large heat flow for temperatures below about 50 K and film thickness

greater than about 0.5 monolayers. The anomalous heat transport is much less

with N2 gas

*NIST Center for Applied Mathematics

-f-Contractor

65
Metal Oxidation and Ignition/Combustion in High Pressure Oxygen

J.W. Bransford, J.A. Hurley, K.M. McDermott

A program to study the oxidation rate and ignition/combustion

characteristics of a number of metals and alloys in oxygen, at pressures up

to 34 MPa, has been undertaken for NASA. This program is not only of

interest to NASA and the aerospace industry, but also to producers,

transporters, and users of liquid and gaseous oxygen.

In one experiment, we heat the top surface of a cylindrical sample by a

specially tuned and focused CO2 laser beam. Interior and exterior

temperatures are measured before, during, and after ignition. High-speed

movies of the ignition and ignition/combustion process are also made. From

the above data, spontaneous ignition temperature, ignition temperature, and

ignition/combustion morphology can be determined. NASA will use the results

to design safer components for launch vehicles, such as the Space Shuttle,

which use large quantities of liquid oxygen at high pressures. The results

are also directly applicable to industrial handling of high-pressure oxygen.

A second experiment will generate more fundamental data: oxidation rate

as a function of temperature and oxygen pressure. To obtain this data, a

Thermogravimetric/Differential Thermal Analysis (TGA/DTA) apparatus has been

designed and is presently under construction. The data from this apparatus,

in conjunction with heat- transfer studies, can be used to evaluate the

suitability of a material for use in specific oxygen system applications.

Development of SRM's

D.R. Smith

Research has been directed toward the establishment of several thermal

property Standard Reference Materials (SRM's).

Research for the development of high- temperature insulation SRM's is

funded by DoE. These insulation SRM's will fill an existing gap in the range

of available thermal conductivity SRM's and are of interest to researchers

and manufacturers in the chemical, insulation, and building industries.

Microporous fused silica, solid ceramic, and ceramic fiber insulation are

currently being developed as SRM candidates. Work is beginning on

determining thermal conductivity of expanded- foam insulations.

Reaction Systems

B. Bateman, J.F. Welch, J.D. Siegwarth, R. Widrig, M. Scurry, T. Zacher, K.

Johnson, G. McKinney

Under a continuing effort supported by the Air Force, a test bed has

been developed to test novel reactors at unusual conditions. Of particular

interest is the ability to test gas/solid/liquid reactions at low pressure.

66
The preliminary phase of this project centered on evaluation of density

and viscosity of liquid solutions to be used in the reactor test phase.

Measurements of density and viscosity were made on aqueous electrolyte

solutions at temperatures from 253 to 292 K. Previously, no such data

existed in the literature for solutions such as concentrated KOH in water

below the normal freezing point of water. As a result of these measurements,

new empirical expressions were developed which complement and extend those

previously reported for such solutions above 273 K.

Another research effort, focusing on chemical reactions at unusual

conditions, has been initiated to address some of the problems associated

with destruction of hazardous chemical wastes. The advantages of oxidation

in supercritical water include: (1) conditions are such that only one phase

exists, therefore, no mass transfer resistances due to phase boundaries

occur; (2) a liquid-phase oxidant is used thereby assuring intimate mixing

and substantial reduction in the capital and operating costs compared to

systems using compression of gas phase oxidants (C>2, air); (3) no

pretreatment of the feed stock is required; and (4) the process may be used

to treat organics at very low concentrations in the aqueous phase.

The focus of the effort is to investigate the application of oxidation

of organic chemical wastes in supercritical water. A continuous flow reactor

has been constructed to operate at 33 MPa and 800 K. Preliminary results

indicate that compounds such as aromatics and substituted glycols can be

readily removed from aqueous waste streams. Typical conversions are 90 to 95

percent, with residence times on the order of a few seconds and feed

concentrations of 5000 ppm organic in water.

5. PUBLICATIONS

Arp, V.D.

,

HEPROP-88: A computer code for helium properties, Proc

Int.

Cryogenic Eng. Conf .

,

Southhampton, England, July 1988 (in press).

Bransford, J.W., Billiard, P.A.

,

Hurley, J.A., McDermott, K.M. and Vazquez,

I., The ignition characteristics of several alloys for use in oxygen

systems, NASA/MSFC Earth- to Orbit Conference, NASA CP- 3023, Vol. 2, pp

758-785 (1988).

Bransford, J.W., Billiard, P.A.

,

Hurley, J.A. and Vazquez, I., The

development of combustion from a quasi- stable high temperature for the

iron based alloy UNS S66286, in Flammability and Sensitivity of

Materials in Oxygen- Enriched Atmospheres: Third Volume, Vol. STP 986,

pp. 146-157 (Sept. 1988), ASTM, Philadelphia, PA.

Bransford, J.W., Hurley, J.A., McDermott, K.M. and Vazquez, I., The ignition

characteristics of UNS S66286 in pressurized oxygen, NIST Interim Report

(in press)

67
Brown, R.J.C., Callanan, J.C., Weir, R.D. and Westrum, E.R. Jr., The thermodynamics of ammonium indates. I. The heat capacity of the ammonium

salt (NH4 ) o• InCl^ ° HoO from 8.5 to 349 K, J. Chem. Thermodyn. , Vol. 20,

pp. 847-853 (1988).

Callanan, J.E., McDermott, K. and Westrum, E.J. Jr., Fusion of mercury, a new

certified standard for differential scanning calorimetric use, J. Chem.

Thermodyn. (submitted)

Callanan, J.E., Weir, R.D. and Westrum, E.J. Jr., The thermodynamics of the

divalent metal fluorides, I. Heat capacity of lead tetrafluorostammate

,

PbSnF4 , from 10.3 to 352 K, Canadian J. Chem., Vol. 66 , No. 4, pp

549-552 (1988).

Callanan, J.E., Development of standard measurement techniques and standard

reference materials for heat capacity and heat of vaporization of jet

fuels, NIST Interim Report (in press).

Callanan, J.E., Acosta, S.M., Brown, R.J.C., Westrum, E.F., Jr. and Weir,

R.D. , The thermodynamics of ammonium indates, II. The heat capacity of

the ammonium pentabromoindate monohydrate salt (NH4• InBr5

) ’H2 O from 7.8

to 348 K, J. Chem. Thermodyn., Vol. 20 (in press).

Callanan, J.E., Weir, R.D. and Westrum, E.F., Jr., The thermodynamics of the

divalent metal fluorides, II. Heat capacity of the fast ion conductor

BaSnF4 from 7 to 345 K, Int. J. Thermophys . (submitted).

Daney, D.E., Ludtke , P.R. and Kashani , A., Performance in Hell of a

centrifugal pump with a jet pump inducer, Cryogenics, a special edition

for Proc. of 1988 Space Cryogenics Workshop, Frascati (Rome), Italy,

Aug. 1988 (in press).

Dale, B.E., Predicting the thermodynamic parameters of protein unfolding,

Science (submitted)

Daney, D.E., Cavitation in flowing superfluid helium, Proc. of Space

Cryogenics Workshop, Madison, WI , June 22-23, 1987, Butterworth &

Company, Ltd., Plenum, MA, pp . 132-136 (1988).

Daney, D.E., Behavior of turbine and venturi flowmeters in super fluid

helium, Adv. in Cryog. Eng., Vol. 33, pp . 1071-1079 (1988).

Evans, J.D. and Sikdar, S.K., Biodegradable plastics: The time is now?,

Chemtech. (submitted).

Giarratano, P.J., Owen, R.B., Kumakawa, A. and Arp, V.D., Transient heat

transfer studies in low-gravity using optical measurement techniques,

J. Thermophys. Heat Transfer (submitted).

Giuliano, K.A. and Szlag, D.C., Aqueous two-phase protein partitioning with

textile dyes as affinity ligands, Anal. Biochem. (submitted).

68
Hands, B.A., Arp, V.D. and McCarty, R.D., HEPROP-88: A computer code for

helium properties, Cryogenics (submitted).

Heaney, M.D. and Pellegrino, J.J., Increased facilitated transport related to

microstructural changes in heat treated ion-exchange membranes, J. Mem.

Sci. (submitted).

Hord, J., Center for Chemical Engineering Technical Activities: FY87, Nat.

Bur. Stand. (U.S.), Interim Report NBSIR 87-3079 (Feb. 1988).

Huber, M.L. and Jones, M.C., A frequency response study of packed bed heat

transfer at elevated temperatures, Int. J. Heat Mass Transfer, Vol. 31,

No. 4, pp. 843-853 (1988).

Hust, J.G. and Smith, D.R., Round-robin measurements of the apparent thermal

conductivity of two refractory insulation materials, using

high- temperature guarded-hot-plate apparatus, Nat. Bur. Stand. (U.S.),

Interim Report, NBSIR 88-3087 (Apr. 1988).

Hust, J.G. and Smith, D.R., Fibrous alumina- silica insulation board as a

candidate standard reference material of thermal resistance, Nat. Bur.

Stands (U.S.), Interim Report, NBSIR 88-3094 (June 1988).

Hust, J.G., Filla, B.J., Hurley, J.A. and Smith, D.R., An automated

high- temperature guarded-hot-plate apparatus for measuring apparent

thermal conductivity of insulation, Nat. Bur. Stand. (U.S.), Interim

Report, NBSIR 88-3089 (May 1988).

Hust, J.G. and Adams, R.D., A round robin on apparent thermal conductivity of

several loose -fill insulations, ProcASTM STP Meeting, Bal Harbor, FL

(Dec. 1987).

Hust, J.G., Filla, B.J., Hurley, J.A. and Smith, D.A., An automated

high- temperature guarded-hot-plate apparatus for measuring apparent

thermal conductivity of insulation between 300 K and 750 K, ASTM Symp

on Insulation Materials, Testing and Applications, ASTM STP 922 (1988).

Jones, M.C. and Giarratano, P.J., Heat of condensation of supercritical fluid

mixtures, AIChE J. (submitted).

Jones, M.C. and Perkins, R.A.

,

The use of dye tracers in the study of free

convection in porous media, Proc. of the Sixth Symp. on Energy

Engineering Sciences, Argonne Nat'l Lab., Argonne , IL, May 4-6, 1988,

DOE Publication (in press).

Kirkkopru, A., Noble, R.D. and Bunge, A.L., Amine phase partitioning using

emulsion liquid membranes, Chem. Eng. Comm., Vol. 64, pp . 207-215

(1988).

Levois, J.S., Perkins, R.A. and Kobayashi, R. , Heats of dissociation of

hydrates of some light hydrocarbons and their mixtures, Spec. Proc.

Issue, Int. J. Thermophys . (submitted).

69
Louie, B. and Steward, W.G., Transient heat transfer to liquid hydrogen using

pulsed or step power inputs, Proc. of 12th Int. Cryogenic Eng. Conf. (in

press)

Ludtke, P. and Storch, P. , Survey of instrumentation for slush hydrogen,

National Aerospace Plane (NASP) Program Office Special Publication (in

press)

Ludtke, P.A. and Daney, D.E., Cavitation characteristics of a small

centrifugal pump in He I and He II, Cryogenics, Vol. 28, pp . 96-100

(Feb. 1988).

Ludtke, P.R.

,

Daney, D.E. and Steward, W.G., Performance of a small

centrifugal pump in He I and He II, Adv. in Cryog. Eng., Vol. 33, pp

515-524 (1988).

McFaddin, S., Brennan, J.A. and Sindt, C.F., NBS-Boulder gas flow facility

performance, American Gas Association, 1988 Operating Section Proc., pp

492-495 (1988)

,

American Gas Association, Arlington, VA.

Munukutla, L.V.

,

Jones, J.A. and Radebaugh, R. , Saran carbon cryogenic

regenerator for liquid helium, Proc. 1988 Interagency Meeting on

Cryocoolers (in press).

Noble, R.D. and Way, J.D., Liquid membranes, Ion Exch. Solvent Extr. - A

Series of Advances, Vol. 10, No. 2, pp . 63-103 (1988).

Pandit, A., Sawant, S.B., Joshi, J.B., Perkins, R.A. and Sikdar, S.K.,

Rheological properties of dextran, polyethylene glycol, bovine serum

albumin (BSA) and their mixtures, J. Chem. Eng. Data, (submitted).

Pellegrino, J.J., Nassimbene, R. and Noble, R.D., Facilitated transport of

CO2 through highly swollen ion-exchange membranes: The effect of hot

glycerine pretreatment, Gas Separation and Purification (submitted).

Radebaugh, R. , Chowdhury, K. and Zimmerman, J., Optimization of a pulse tube

refrigerator for a fixed compressor swept volume, Proc. of 5th Int.

Cryocooler Conf.

,

Air Force Report (in press)

Roder, H.M.

,

de Castro, C.A.N. and Perkins, R.A.

,

Thermal conductivity,

thermal diffusivity and heat capacity of nitrogen from transient

hot-wire measurements, Spec. Proc. Issue, Int. J. Thermophys

(submitted)

Siegwarth, J.D., Vortex shedding flowmeters for high velocity liquids, Int.

J. Heat Fluid Flow (submitted).

Siegwarth, J.D. and Voth, R.O., A miniature cryogenic high vacuum valve, Adv,

Cryog. Eng., Vol. 33, pp . 1153-1159 (1988).

70
Sikdar, S.K., Sawant, S.B. and Joshi, J.B., Partition coefficient of bovine

serum albumin in two-phase aqueous systems, Biotechnology Techniques,

Vol . 2, No. 1, pp. 41-46 (Feb. 1988).

Sikdar, S.K., Patil, T.A., Sawant, S.B. and Joshi, J.B., Mass transfer

coefficients in two-phase aqueous extraction, AIChE J. (submitted).

Smith, D.R. and Hust, J.G., Microporous fumed-silica insulation board as a

candidate standard reference material of thermal resistance, NIST

Interim Report (in press).

Sparks, L.L.

,

Dube, W.P. and Slifka, A.J., Thermal conductivity of selected

foams and systems from 100-300 K, Nat. Bur. Stand. (U.S.), Interim

Report, NBSIR 88-3086 (Jan. 1988).

Storch, P.J. and Radebaugh, R. , Development and experimental test of an

analytical model of the orifice pulse tube refrigerator, Adv. Cryog.

Eng., Vol. 33, pp. 851-859 (1988).

Szlag, D.C. and Giuliano, K.A.

,

A low-cost aqueous two-phase system for

enzyme extraction, Biotechnol. Tran, (submitted).

Todd, P.W.

,

Szlag, D.C., Delcourt, S.G., Plank, L.D., Kunze, M.E.,

Kirkpatrick, F.H. and Pike, R.G., Investigations on gel forming media

for use in low gravity bioseparations research, Adv. Space Res.

(submitted)

Vazquez, I., Russell, M.P., Smith, D.R. and Radebaugh, R. , Helium adsorption

on activated carbons at temperatures between 4 and 76 K, Adv. Cryog.

Eng., Vol. 33, pp. 1013-1021 (1988).

Voth, R.O. and Siegwarth, J.D., An electronic balance for use in weighing

foams at cryogenic temperatures, Adv. Cryog. Eng., Vol. 33, pp

1089-1095 (1988).

6. CONFERENCES

Session [11] on Government Research Activities, AIChE Summer National

Meeting, Denver, CO, Aug. 22, 1988. Organized and co-chaired by J. Hord.

Chemical Engineering Education in a Changing Environment, Engineering

Foundation Conference, Santa Barbara, CA, Jan. 17-22, 1988. J. Hord served

on Program Planning Board and chaired session on separations.

The 43rd Annual Calorimetry Conference, Bartlesville, OK, Aug. 1988. J.

Callanan was chairman elect of the conference.

Transport Fundamentals in Bioseparation, AIChE Annual Meeting, New York, NY,

Nov. 1987. Sessions organized and chaired by S.K. Sikdar.

71
Novel Bioseparations, North American Chemical Congress, Toronto, Canada, June

1988. S.K. Sikdar organized four sessions.

Bioseparations, Colorado Biotech Symposium, Colorado State U. , Fort Collins,

CO, Sept. 1988. S.K. Sikdar served as panel member.

AIChE Summer National Meeting, Denver, CO, Aug. 1988. B.R. Bateman was

national program vice chairman.

72
TECHNICAL ACTIVITIES

OF THE

THERMOPHYSICS DIVISION

N.A. Olien, Chief

1. INTRODUCTION

The research of the Thermophysics Division focuses on the thermophysical

properties and dynamic behavior of fluids and solids, with particular

emphasis on properties and substances of current and future importance to the

chemical and related industries.

The approach is to conduct research on fundamental theoretical models,

new concepts and phenomena, and predictive algorithms in synergism with

experimental programs. The experimental research is aimed at developing new

measurement techniques and providing highly accurate data for the properties

of carefully selected pure fluids and mixtures, as well as high temperature

solids, which are representative of broad classes of fluids and materials

encountered in many industries. An essential ingredient of these efforts is

the critical evaluation and correlation of data leading to the publication of

Standard Reference Data. Standard Reference Data take the form of

conventional correlations and tables, but more recently the form has been

predictive models as computer code. These codes are an important product of

this research.

All industrial processes and certainly those in the chemical and fuel

industries are steadily moving toward alternative and more complex base

feedstocks, which in turn yield more complex, and often corrosive and

hazardous, conversion products and often involve higher temperature

processes. Modern plants must handle a larger variety of feedstocks and must

produce a broader range of output products. A very significant factor in the

application of the research described here is the widespread use of process

simulation and computer-aided design in the development, optimization, and

control of processes and plants in the chemical, fuel and related industries.

Key ingredients of all process simulators are the data and models for the

properties of fluids and other materials encountered in the processes. Major

outputs of the research program described here are property data in the form

of predictive theoretical models and correlations which can be readily

incorporated into. process simulator and process control algorithms.

Thermophysics Division research addresses scientific issues of national

importance for which NIST expertise, and its impartial position, are critical

to data acceptance and to the resolution of problems of equity in trade for

such products as ethylene, natural gas, steam, and carbon dioxide. The

majority of the work is directed toward problems of the future. These

73
include, but are not restricted to, the following: (1) fluids encountered in

natural gas and oil processing, refrigeration and foam blowing, high value

and commodity chemicals from new feedstock sources, and new processing

techniques such as supercritical extraction; (2) fluid mixtures encountered

in bioprocess engineering, which are essentially aqueous solutions containing

macromolecules; and (3) high temperature solid and fluid property needs of

government agencies for energy, defense, and aerospace (e.g., DoE, DoD,

NASA), where NIST expertise can provide specific results. The strategy is to

perform basic research, generic to the science underlying the chemical, fuel,

power, and aerospace industries, which requires the special role of NIST as

an impartial national laboratory excelling in experimental and theoretical

results and their interpretation.

2. GOAL

The goal of the Division is to provide standard measurement procedures,

benchmark experimental data, and reliable methods of predicting key

thermophysical properties of industrially important chemicals, fuels, and

related fluids, and of high temperature solids. These data are used in the

innovation, design, and control of chemical processes, to ensure equity in

domestic and international exchange of products, and by NIST and others as

benchmark data to extend versatile computational techniques which reliably

predict the properties of broad classes of substances over extended operating

ranges

The output of this program assists the chemical, fuel, power,

refrigeration, polymer processing, aerospace, and related industries in

maintaining and enhancing their competitiveness in the international

marketplace by making their processes more efficient, more able to accept a

broader array of input feedstocks, and by providing avenues for the

development of new products.

3. GROUP AND PROGRAM FUNCTIONS

The research of the Division is performed within two groups and one

Division Office program.

GROUPS

Equation of State and Statistical Physics (Gaithersburg, MD)-

M.R. Moldover, Group Leader

This Group conducts experimental, theoretical, and computer simulation

studies of the thermodynamic and transport properties of fluids, fluid

mixtures, and solids, including supercritical and aqueous systems, polar

fluids and mixtures, refrigerants and refrigerant mixtures, interfaces and

wetting layers, and liquids, glasses, and molecular aggregates. The Group

develops new measurement techniques, thermodynamic models, and molecular

theories to describe the thermophysical behavior of condensed matter, and

provides critically evaluated technical information (data, theoretical

74
models, computer models) on these thermophysical properties. Major non-CCT

sponsors of the work of this Group include the DoE, NASA, and the NIST Office

of Standard Reference Data (OSRD)

• Properties of Fluids (Boulder, CO)-W.M. Haynes, Group Leader

This Group has a research program which integrates experimental

measurements, theoretical studies, and critical evaluation of data, all

designed to lead to a basic understanding of fluid behavior. Outputs are

data and theoretically based predictive models for the properties of

technically important complex mixtures and pure fluids . The fluids of

interest include common inorganics, industrial chemicals, hydrocarbons,

refrigerants, coal conversion products, heavy oils, and biochemical

solutions. Principal non-CCT sponsors of the work of this Group include the

DoE, the Gas Research Institute, the DoD, industrial consortia, and the OSRD.

DIVISION OFFICE PROGRAM

Subsecond Thermophysics (Gaithersburg, MD)-A. Cezairliyan, Project

Leader

This program develops dynamic (millisecond and microsecond) measurement

techniques and performs measurements of selected thermophysical properties of

high temperature materials over the range 1500 - 10 000 K. Materials

investigated include high temperature conductors and nonconductors,

refractory materials, metallic composites, and high temperature Standard

Reference Materials. The unique capabilities of this laboratory provide the

means to perform accurate measurements in temperature regimes and at high

heating rates where conventional techniques fail.

4. SELECTED PROJECT SUMMARIES

EQUATION OF STATE AND STATISTICAL PHYSICS GROUP

Aqueous Systems at High Pressures and Temperatures

J.M.H. Levelt Sengers , J.S. Gallagher, R.D. Mountain, G. Morrison, M.L. Japas

(Guest Researcher), H. Sato (Guest Researcher)

(1) Organizational activities occurred at all levels, from the local to

the international.

At the 10th Symposium on Thermophysical Properties at Gaithersburg, June

1988, Levelt Sengers co-organized and chaired five sessions on aqueous

solutions. She, Gallagher, and Japas presented papers on aqueous solutions

at this meeting.

At NIST, collaborative projects have been started with Neumann, Garvin,

Archer and Wang in the Chemical Thermodynamics Division. One of these is an

up-to-date formulation of the dielectric constant of water and steam, for

75
recalculation of the Debye -Huckel initial slopes at all temperatures and

pressures. Another is a joint proposal for evaluation and improvement of

existing models of aqueous electrolyte solutions at high temperatures, and

for modeling such solutions at lower densities typical of supercritical

water. This proposal is expected to receive the backing of the ASME Research

Committee on Water and Steam.

On the national level, Levelt Sengers has participated in the merger of

the ASME Research Committees on Water and on Steam, is on the Executive Board

of the Joint Committee, and is the National Delegate to the International

Association for Properties of Steam (IAPS). She also presented a talk on

steam as a supercritical solvent at an International EPRI meeting (Cycle

Chemistry in Fossil Plants) in Seattle, August 88.

On the international level, Levelt Sengers, Gallagher, and Japas

attended the one -day Seminar on Chemical Thermodynamics in Industrial Water

at the IAPS meeting in Vancouver, August 1988, and all gave presentations at

the IAPS working group sessions. Levelt Sengers chaired the Working Group-A

sessions and participated in the Prague Program Committee meeting.

IAPS -sponsored collaborations have been those on the refractive index of

water and steam (with Schiebener) now nearing completion, and, with Sato, a

collection of all experimental data on thermodynamic properties of water and

steam; both projects are intended to be J. Phys . Chem. Ref. Data

publications

(2) Scientific progress in the past year includes a new model for the

temperature dependence of Henry's law at high temperatures (Japas and Levelt

Sengers, accepted, AIChE J.), a molecular dynamics study of hydrogen bonding

in water at high temperatures (Mountain, J. Chem. Phys., in press), a

thermodynamic model for NaCl in steam at near critical and supercritical

temperatures (Gallagher and Levelt Sengers) , and an experimental

determination of the coexistence curve and electrical conductivity of an

ionic fluid near a consolute point (Japas) - -fully nonclassical behavior was

found.

Morrison prepared a manuscript that exhaustively models electrolyte

solutions near the critical point of water. The paper was prepared for the

Proceedings of the Symposium on High Temperature Aqueous Chemistry that was

held in August 1987, in Provo, Utah, and will appear in J. Solution Chem. in

early 1989.

Thermodynamic Properties of Fluid Mixtures

E.J. Clark, J.M.H. Levelt Sengers, G. Morrison, M. Patron (Guest Researcher)

Clark replaced the pressure transducer and made several other

improvements in the piston- driven visual variable -volume VLE apparatus and

took some vapor pressure data on isobutane. She designed a simple visual

variable -volume cell and gas handling system for study of phase equilibria in

pressurized polymer solutions.

76
Morrison, with assistance from Patron, set up and calibrated the

mechanical oscillator (vibrating tube) dilatometer, which now operates

between 0 and 90° C.

Morrison finalized the design of the high-pressure continuous -dilution

dilatometer, gathered all the parts for it, and began its fabrication. A

bath was also constructed for this instrument.

Levelt Sengers continued her NATO collaboration with Peters in Delft. A

paper was drafted for the Prausnitz Festschrift and the November 1988 AIChE

meeting, on the topic of tricriticality in propane - n-alkane systems.

Work on the system C 2Hg - CO2 has been postponed in view of the urgency

of the work on refrigerants.

Critical Survey of Compiled Data Sources for Bioprocess Engineering

J. Hubbard, J.M.H. Levelt Sengers, E.J. Clark

This study addresses questions concerning data requirements, data

availability and quality, measurement techniques, and correlation methods for

compiled data sources relevant to biotechnology and bioprocess engineering.

The procedure is to use library and other data base sources (computerized or

not) to extract information on compiled data for carefully selected topics,

where relevance to bioengineering is the primary criterion for selection.

Reports take the form of annotated, critical bibliographies on such

topics as isoelectric points of proteins (as determined by gel

electrophoresis), oxygen solubility in bioreactor media, and oxygen mass

transfer through the gas-liquid interface in bioreactors. The product will

consist of a collection of these reports along with specific recommendations

for future data acquisition and evaluation, plus recommendations for the

development of new measurement techniques and correlation methods in

bioprocess engineering.

Electrophoretic Light Scattering From Macromolecular Solutions

and Colloidal Dispersions

J.B. Hubbard, A.K. Gaigalas,* S. Woo*

The analysis of quasi-elastic scattered laser light from a saltcontaining solution in the presence of an external electric field is called

electrophoretic light scattering (ELS). In an "ideal" colloidal dispersion

or macromolecular solution the Lorentzian half-width gives the diffusion

coefficient while the Doppler shift gives the mobility, which can then be

related to the surface charge of a particle. ELS is superior to conventional

light scattering because of the ease of resolving mixtures whose components

have different surface charges. Compared to gel electrophoresis, ELS is a

sensitive in-situ diagnostic probe rather than a separation technique. In

ELS, no concentration gradients are produced, the fluid medium is wellcharacterized, and very large particles such as cells or bubbles are not

77
trapped as in a gel. We have begun an experimental ELS study of latex sphere

dispersions in electrolyte solutions to test our equipment design and to

scrutinize current theories. By using a low frequency AC electric field we

have succeeded in completely eliminating electro-osmotic convection, which is

the most important resolution- limiting nuisance in all current commercially

available ELS devices. In addition, we have observed novel low frequency

harmonics in the ELS homodyne correlation function which are apparently

related to electrohydrodynamic instabilities in the electrical double layers

surrounding the colloidal particles. A publication based on these results is

in preparation. In addition, we have recently published a theoretical

analysis of the effects of conformational dynamics of solvated macromolecules

on the observed spectrum. The idea is that one can use ELS to monitor

simultaneously both the statics and dynamics of biologically significant

conformational changes, such as protein denaturations . As a future project,

we plan a novel study of ELS in a gel- like medium as a direct probe of

particle-gel dynamical interactions.

^Chemical Process Metrology Division

Computer Simulation Studies of Liquids and Agglomerates

R.D. Mountain, J.G. Amar

The molecular level computer simulation of the properties of liquids has

proven to be an essential technique for evaluating formal, statistical

mechanical models of condensed matter. Our program both develops and

utilizes simulation methods to model thermal properties of fluids in terms of

the molecular level interactions. The NIST supercomputer is an essential

tool for this work. During the past year, our efforts have been directed

towards: (a) glassy states of liquids, (b) the structure of high temperature

reduced density states of water, (c) fluid-fluid phase equilibria, and

(d) the development of an optical diagnostic probe of soot agglomerates. The

work on water and phase equilibria is related to experimental work in the

Division. The work on agglomerates is a collaborative effort with the NIST

Center for Fire Research.

Our investigation of glassy states of a simple mixture has resulted in a

novel measure of the ergodic properties of supercooled and glassy states.

This measure, called the energy metric, is being investigated further as it

provides a new way of thinking about the structure of the theory of glass

formation. The degree of hydrogen bonding present in water has been

determined for a model of water for temperatures between 273 K and 1100 K and

for densities between 100 kg/m^ and 1000 kg/m-^ . A scaling property for

hydrogen bonding as a function of temperature exists for densities greater

than 600 kg/m^ and does not exist for densities less than 450 kg/m^ . A new

approach to the simulation of fluid- fluid phase transition has been examined.

It is more efficient than other methods for liquid-gas calculations but not

so for liquid- liquid calculations. A scheme for using optical properties to

characterize soot agglomerates has been proposed. This scheme, which employs

the complex index of refraction, the UV scattering, and the optical

absorption of the agglomerates, yields the size of the agglomerates, the

78
number of primary particles making up the agglomerates, the size of the

primary particles , and the concentration of agglomerates in a sample . This

scheme was developed using simulation- generated agglomerates and their

calculated optical properties as a guide and as a test case.

Low- Frequency. Low- Shear-Rate Viscosity Measurements

R.F. Berg, M.R. Moldover

Collaborators: J.S. Huang (Exxon), J. Ritter (University of Virginia)

As part of a NASA- sponsored project for testing the theory of dynamic

critical phenomena, we have developed a unique viscometer. The viscometer is

a torsion oscillator which operates at a low frequency (0.5-5 Hz) and a low

shear rate (0.05-0.5 /s~^) and can be used at pressures to 10 MPa. The

viscometer was used to measure the viscosity enhancements that occur near the

consolute points of binary liquid mixtures. These mixtures are models for

the liquid-vapor systems to be studied in microgravity. The results for four

mixtures have been published in the Journal of Chemical Physics. This work

will be the definitive experimental reference for the critical exponent of

the viscosity for many years.

In collaboration with J.S. Huang, a study of the viscosity increase near

the percolation transition of a microemulsion has been published.

Spherical Acoustic Resonators for Thermophvsical Properties

and Standards Measurements

M.R. Moldover, A.R.H. Goodwin, B.A. Young1 ove , N.V. Frederick

Collaborators: J.B. Mehl (University of Delaware), J.P.M. Trusler (Imperial

College , London)

The 3 -liter resonator that had been used to measure the universal gas

constant R was used to make exceedingly accurate measurements of the speed of

sound in argon near the temperature of the triple point of gallium (Tg)

This is one of several highly reproducible fixed points that are being

established for the 1990 International Temperature Scale. In 1990, the

present International Practical Temperature Scale (IPTS68) that is used to

calibrate all thermometers, will be replaced with a new scale that better

approximates the thermodynamic temperature T for which thermodynamic

calculations and relationships are exactly true. We found that

Tg = (302.916 9 + 0.0005) K and that near Tg the error in IPTS68 is:

T - IPTS68 = (-6.5 + 0.5) mK. This resonator will be used to redetermine the

triple point of mercury (approximately 233 K) and to interpolate between the

mercury and the gallium points.

We have demonstrated the feasibility of measuring the volumetric thermal

expansion of a resonator with an accuracy of 2x10 by using in situ

microwave resonances. This technique will be used to extend acoustic

thermometry to very low and very high temperatures

79
A 1/8 -liter resonator was assembled in Gaithersburg for measuring the

speed of sound and ideal gas heat capacity in two environmentally acceptable

refrigerants. This resonator and its associated pressure vessel and

thermostat were designed to make speed of sound measurements accurately,

rapidly, and routinely. In the temperature range -60°C to +70° C, an isotherm

can easily be measured in one working day.

Refrigerants and Refrigerant Mixtures

G. Morrison, J.S. Gallagher, L.A. Weber

Collaborators: D. Didion*, M.O. McLinden*

As part of the long-term goal of the refrigerant mixture project,

M. McLinden and G. Morrison presented a paper at the 1988 AIChE Spring

Meeting in New Orleans that summarized their work on mixtures. They have

found that the behavior of refrigerant mixtures falls into a definite

pattern, in which the salient molecular parameter is the dipole moment

divided by the effective hard kernel volume. This quantity, effectively a

surface charge density arising from the charge separation that produces the

dipole, can be related to composition variations in the mixture as well as

the mean value of the empirical mixing parameter. The charge density and

these empirical mixing quantities appear to be related by the same factor for

all mixtures. They also found that this quantity could be incorporated into

the modified hard sphere equation of state; doing so nearly eliminated the

undesirable density dependence of the hard kernel and attractive term

parameters in the equation of state.

The year has also seen a redoubled effort in property measurement for

the proposed alternative "ozone safe" refrigerants. The saturation

properties of four pure materials and one mixture have been measured by

G. Morrison and D. Ward. The speed of sound and determination of the perfect

gas heat capacity for two pure materials have been measured by M. Moldover

and A. Goodwin by using the spherical acoustical resonator. L. Weber

measured the dilute gas properties for two refrigerants with the automated

Burnett apparatus. Finally, J. Schmidt and H. Chae have measured the surface

tension of two refrigerants. These measurements provide a broad data set on

which to base the correlation work being done by M. McLinden, with charts

being produced by J. Gallagher. This effort draws together a unique

collection of skills and talents in addressing the serious matter of

industrial change-over to the alternative refrigerants.

*NIST Center for Building Technology

The Langmuir Film Balance

G. Morrison

Collaborator: I.L. Pegg (Catholic University)

When the automated film balance was under development, two phenomena

were examined as a way of testing the versatility and sensitivity of this

instrument. These phenomena were related to a measurement of the "liquid80
vapor" spreading pressure of pentadecanoic acid at 35° C, a temperature that

is disputably above the critical point for this material. The measurement

indicated the presence of two -phase equilibrium and the nature of the

transition between two "liquid" states in the same material. The study

concurred with a recent assertion that the transition is first order, in

definite conflict with a long-held view that the transition was of higher

than first order. Detailed measurements were made of this transition, the

liquid- expanded to liquid-compressed transition, to study its high

temperature behavior; as the temperature is raised, the molar area change

becomes progressively smaller. There are several scenarios that could lead

to the disappearance of the transition. In pentadecanoic acid, the

transition appears to intersect another phase line, the monolayer collapse

transition; the high temperature behavior is thus apparently obscured. In

addition to the work on single -component monolayers, preparations are being

made to study binary mixtures with a "liquid- liquid" immiscibility

Preliminary measurements on a mixture of octadecan-l-ol and 9-cis-octadecanl-ol have been made. This study will lead to study of mixtures of more

complex species, phospholipids and cholesterol, for example, which are the

major components of many plant and animal cell and organelle membranes.

Interfacial Phenomena

M.R. Moldover, J.W. Schmidt, R.F. Kayser, J.C. Rainwater

The model we developed last year for predicting liquid-vapor interfacial

tensions in the critical region of mixtures, such as CO2 + butane, from phase

equilibria measurements, has been applied to predicting the surface tension

of liquid air and to correlating recent measurements of the surface tension

of argon + krypton mixtures.

Interfacial structure of the liquid- liquid interface in several binary

mixtures, including carbondisulfide + methanol, nitrobenzene + n- decane,

methanol + cyclohexane, and isobutyric acid + water, have been studied using

state-of-the-art ellipsometry in wide temperature ranges approaching the

consolute points of the mixtures. The data were used to test theories of the

interfacial structure. One class of theories, known as density profile

theories, describes the interface as having a smooth variation of density

(composition, refractive index, etc.) as one moves from deep in one phase

through the interface and into the second phase. A second class of theories,

known as capillary wave theories, describes the interface as a sharp

interface roughened, however, by capillary waves or ripplons . Our

ellipsometry indicates that both theories (density profile and capillary

wave) predict an interfacial thickness that is smaller than the measured

thickness. The temperature -dependent thicknesses of all of the mixtures

studied can be scaled with the bulk correlation length to obtain a universal

number. At present, the best model that describes the interface is a

combined density profile and capillary wave model. An important implication

of the model is that the interfacial tension must increase for short

wavelength ripplons.

81
This implies that an interface confined to a small pore or a nucleating

droplet has an interfacial tension much higher than that of the macroscopic

interface. We are attempting to test this by direct measurements.

Theoretical efforts have focussed on mechanisms for stabilizing very

thin liquid films against external fields such as gravity. The dispersion

force mechanism has been studied, and measurements agree quantitatively with

theory in the special case of a nonpolar pure fluid in contact with a single

vertical wall. The theory now predicts the thickness of thin films of a

polar phase that intrudes between an ionizable substrate, such as glass, and

a nonpolar liquid phase. The theory predicts the thickness changes upon the

addition of high concentrations of salt.

PROPERTIES OF FLUIDS GROUP

Corresponding States Theories of Fluid Mixtures

J.F. Ely, J.R. Fox, M.L. Huber

Collaborators: D. Erickson (Conoco), R.T. Jacobsen (University of Idaho),

T.S. Storvick (Guest Researcher)

In recent years there have been great advances in our microscopic

understanding of fluid mixture behavior. Nonetheless, one of the most

reliable methods for predicting mixture thermophysical properties is based on

corresponding states concepts which were theoretically formulated many years

ago. In this project, we are attempting to further improve corresponding

states models for systems which contain large size and polarity differences.

The approach incorporates computer simulations for model mixtures which

provide the radial distribution function as well as other thermodynamic data.

Theoretical approximations are then made for the radial distribution

functions with the results being incorporated into the statistical mechanical

expressions for various properties. Thus far, we have developed an equation

of state model which is nearly exact for model Lennard- Jones mixtures with

size ratios up to 2. Current work involves extending these results to real

fluids

In addition to these classical studies, a new approach to the

improvement of corresponding states methods is being developed. The method

uses "field space" transformations to describe fluid mixtures in terms of the

behavior of a pure fluid in a fashion very similar to traditional "one fluid"

corresponding states theories, but with two important differences. The

structure of traditional corresponding states methods leads to nonphysical

predictions for the properties of dilute mixtures when coupled to the most

accurate of pure fluid correlations. This is corrected in the new structure.

And the calculation of phase equilibria is numerically simplified in the new

forms, possibly leading to significant savings in design and process

simulation work. A version of the theory, with the pure fluid described by a

cubic equation of state, is currently being tested with experimental binary

mixture data.

82
Supercritical Fluid Properties

J.F. Ely, J.W. Magee, M.L. Huber, T.J. Bruno, S.L. Outcalt, W.M. Haynes,

J . Howley

Collaborators: W.D. Seider (University of Pennsylvania)

Industrial interest in enhanced oil recovery using near-critical carbon

dioxide, in supercritical fluid extraction of fuel materials, foodstuffs, and

pharmaceuticals, and in near-critical custody transfer of commercial

chemicals, has pointed out the need for accurate data and predictive models

for supercritical fluid mixtures. Currently five projects are in progress

which address various aspects of supercritical fluid properties.

The first project, which is sponsored by a consortium of four companies,

one trade organization, and NIST, deals with the measurement and correlation

of PVTx data for carbon dioxide-rich mixtures. Thus far, experimental data

have been obtained for one quaternary, one ternary, and four binary mixtures.

In addition, a predictive model for the thermophysical properties of these

systems has been developed that is more accurate in the near-critical region

than earlier models. The model, DDMIX, is being distributed by the NIST

Office of Standard Reference Data and will be available on-line in the

Chemical Abstracts Network Service.

In the second project, a base of high accuracy, nonanalytic equations of

state has been developed for various pure fluids. Most recently, equations

for methane, normal and isobutane, n-pentane, and carbon dioxide have been

obtained. In the near future rescaled 32 -term BWR equations will also be

available for propane. These equations will be used in advanced

corresponding states models.

In the fourth project, a supercritical fluid chromatograph has been

developed as a tool for physicochemical measurements. Supercritical fluid

chromatography assumes a natural role in thermophysics research as an

intermediary between gas chromatography and high performance liquid

chromatography. The supercritical fluid chromatograph is being used for

studies of diffusion phenomena, heat capacity ratios, and partial molar

volumes

Finally, the fifth project is concerned with supercritical fluid

extraction applications in biotechnology. The potential for extraction of

foods and pharmaceuticals using nontoxic solvents such as supercritical

carbon dioxide has intrigued researchers for several years . Numerous

laboratory- scale separations have been demonstrated, but industrial scale-up

has lagged behind due to the complexity of supercritical fluid extraction

process design and control. This project is geared toward developing cost

efficient extraction processes which can be easily operated. The work is

currently focused on /3-carotene, or provitamin A. This material is a high

cost, moderate volume commodity which is used extensively as a natural food

coloring and to provide vitamin A supplements in foods. The research

involves both an experimental and theoretical component. Measurements are

being made of the solubility, vapor pressure, and transport efficiency of

/3-carotene in supercritical carbon dioxide. These data are then correlated

83
with a suitable equation of state which is part of a unit operations computer

simulation package. The ultimate goal of the project is to provide an

optimized predictive simulation routine which can be used industrially to

design and control supercritical fluid extractions on an industrial scale.

Predictive Computer Packages

J.F. Ely, M.L. Huber, R.D. McCarty, J.C. Rainwater

Collaborator: R.T. Jacobsen (University of Idaho)

One of the primary outputs of the group is a collection of predictive

and/or correlative computer programs which are packaged for end use by

practitioners in science and engineering. Primary packages of this nature

which have been distributed in the past year are MIPROPS, DDMIX, C02PAC and

SUPERTRAPP. All of these programs are interactive in nature and designed to

be user friendly and usable on microcomputers as well as mainframes

MIPROPS is a program which calculates the thermodynamic and transport

properties of twelve pure substances. DDMIX calculates the thermophysical

properties of mixtures (up to seventeen components) with the emphasis placed

on highly accurate mixture densities. C02PAC calculates the properties of

pure carbon dioxide using the Schmidt -Wagner equation of state formalism.

Finally, SUPERTRAPP calculates the thermophysical properties of mixtures (up

to twenty components from a list of 125) using the extended corresponding

states model. All of these except C02PAC are available from the NIST Office

of Standard Reference Data for a nominal charge.

As new models and results are obtained, the list of programs and their

ultimate utility will grow. The extended corresponding states model has

recently been used in the development of computer packages for air and for

mixtures of metallic hexafluorides and perfluorinated hydrocarbons. The

power of the extended corresponding states method (using shape factors) for

predictions has been demonstrated in the development of these latter two

packages, for which experimental data are extremely limited and/or

nonexistent. The work on air properties has also led to a substantial

experimental project to improve the quality of low temperature data for air

and related mixtures.

Complex Fluid Systems

J.F. Ely, M.L. Huber, R.A. Perkins, A.J. Kidnay, G.C. Straty,

T . J

Bruno

Collaborator: G.A. Mansoori (University of Illinois)

Fluid property research has been moving rapidly in the direction of the

study of ever more complex systems. As a result, new experimental techniques

and theoretical methods are being developed to handle such systems.

Currently, one part of this effort involves the behavior of biological fluid

mixtures. Aqueous two-phase partitioning has been analyzed from a molecular

point of view, and statistical mechanical models have been investigated for

84
the interpretation and prediction of such phenomena. Using experimental data

for the polyethylene glycol -dextran-water system, it has been shown that

these models qualitatively predict the general features of the phase behavior

of these systems although the current models fail to provide quantitatively

accurate results.

Heat of mixing measurements are being made on a series of five-membered

ring compounds (furan, tetrahydrofuran, thiophene, tetrahydrothiophene

,

pyrrole, and pyrrolidine) to examine the effects of hydrogen bonding in

aromatic liquids and liquid mixtures. These data will aid in the development

of the theoretical means of predicting the thermophysical properties of broad

classes of these mixtures.

Another area of recent work is the thermophysical properties of reacting

fluids. Under conditions of high temperature and high pressure, even simple

fluids can undergo extensive chemical decomposition. A comprehensive

analytical and reaction screening facility has been developed to help

characterize the behavior of these systems. Experimental data and subsequent

correlations have been provided for methanol, benzene, and toluene.

Protocols for characterizing reacting fluids, for performing reproducible

measurements on them, and for reporting data from such measurements have been

proposed. Development of novel instrumentation, such as a gas

chromatographic detector based on catalytic cracking, is also being pursued.

PVT Measurements and Correlation

J.W. Magee, W.M. Haynes, G.C. Straty, J.B. Howley, V.G. Niesen, J.F. Ely,

D.G. Friend, R.D. McCarty, H. Ingham, N.V. Frederick, R.D. Goodwin

Collaborators: R. Masui (National Research Laboratory of Metrology, Japan)

The group has four operational apparatus to measure the PVT properties

of fluids: an automated isochoric PVT cell operating between 80 K and 450 K

for pressures to 35 MPa; a high temperature, isochoric -Burnett expansion PVT

cell for 300 K to 900 K with pressures to 50 MPa; a low temperature magnetic

suspension densimeter operating between 80 K and 320 K at pressures to 35

MPa; and an automated balance densimeter for 300 K to 500 K at pressures to

20 MPa.- Recent results have been obtained for CO2 , CO2 + N2 , CO2 + CH4 , CO2

+ N2 + CH4 , CO2 + C 2Hg , CO2 + N2 + CH4 + C2H5 , R-13, methanol, benzene, and

toluene. Planned measurements include carbon dioxide plus hydrocarbons, N2 +

O2 + Ar (air), hydrocarbon mixtures simulating natural gas, pentanes, and

binary mixtures with components exhibiting large differences in size and/or

polarity.

A primary output of the group is the correlation of PVT data.

Comprehensive correlations have been completed for methanol, benzene, and

toluene using a nonanalytic equation of state. The Schmidt -Wagner equation

of state has been applied to light hydrocarbons and carbon dioxide with

excellent results, especially in the extended critical region. The 32 -term

modified BWR equation, which has been used extensively for many fluids, has

been applied to monomethylhydrazine . A new comprehensive equation of state

is currently under development for helium.

85
Phase Equilibria Studies

V.G. Niesen, J.E. Mayrath, T.J. Bruno, M.J. Hiza, J.C. Rainwater,

S.L. Outcalt

Accurate phase equilibria data and models are essential in the design

and operation of separation units in the chemical process industry. Several

apparatus are available in our group for the acquisition of such data. A

moderate temperature (300 K to 450 K) phase equilibria apparatus has been

modified to include measurement of liquid and vapor phase densities using

vibrating tube densimeters. After calibration with nitrogen and water at

temperatures from 300 K to 400 K for pressures to 14 MPa and densities

between 0 and 1 g/cm^ , the apparatus was tested with measurements on carbon

dioxide, normal butane, and their mixtures. Both the phase behavior and

density results agreed within experimental uncertainty with reliable

literature values. Other recent measurements have included butanes with

refrigerant R-13. Current work includes binary mixtures of nitrogen and

normal butane, and carbon dioxide and propane, and ternary mixtures of

nitrogen, carbon dioxide, and normal butane and air related mixtures.

A phase equilibria apparatus for measuring dew and bubble point

pressures from 325 K to 800 K at pressures to 35 MPa has been recently used

to obtain data for the methanol and water system over the range 350 K to 650

K. This automated apparatus is unique in that residence times have been

minimized for fluids that react or decompose at high temperatures , and no

sampling is required after a known composition is introduced and maintained

in the cell. A prototype differential refractometer cell for use at high

pressures (70 MPa) and high temperatures (800 K) is undergoing performance

tests. This technique will provide a real time, nondestructive, in situ

means for the determination of binary mixture compositions at extreme

conditions encountered in new technologies in the energy industry.

An apparatus is available for measurements of the fugacity of binary

mixtures containing hydrogen. This technique employs a semipermeable

membrane (palladium/s ilver) through which hydrogen, but not the second

component, can penetrate. By measuring the properties of pure hydrogen, the

fugacity of hydrogen in the mixture can be determined. Results have been

obtained for hydrogen with methane, ethane, propane, isobutane, CO2 , and CO.

Measurements are now in progress for hydrogen and ethylene; a study of the

hydrogen + ammonia and hydrogen + butane systems will follow. Our low

temperature VLE apparatus is currently being reactivated for measurements on

mixtures of air components.

Accurate correlation of VLE data in the critical region is extremely

important in many industrial applications. It is precisely within this

region that conventional methods fail to converge and/or are inaccurate. A

model first developed by Leung and Griffiths has been modified to provide

accurate correlations of phase equilibria data that cover an extended

critical region from the critical pressure locus to about half the critical

pressure. This model has been successfully applied to a large number of

binary mixtures containing helium, nitrogen, oxygen, carbon dioxide, hydrogen

86
sulfide, benzene, refrigerants, alkanes, olefins, alcohols, and ethers. The

model has recently been extended to ternary mixtures of ethane, n-butane, and

n-pentane and of nitrogen, oxygen, and argon (air) and has been used to

predict interfacial tension. A mathematically complex model has been derived

to accommodate VLE in the presence of liquid - liquid equilibria (LLE) . New

theoretical understanding of the nature of the critical locus has been

achieved. Future plans include extension to azeotropic systems and to the

one-phase supercritical region, correlation of coexisting enthalpy data, and

development of predictive techniques using this model.

Thermodynamic Property Measurements and Correlation

J.W. Magee, B.A. Younglove, J.E. Mayrath, H.M. Roder, R.D. McCarty,

N.V. Frederick, M.R. Moldover

There is an awareness in industry that data for the derived

thermodynamic properties (e.g., heat capacity, velocity of sound, enthalpy)

of even simple fluids and mixtures are sparse. Further, the predictions of

such properties from an equation of state are unreliable without data to

check and optimize the forecasts. Isochoric heat capacity (Cy) data have

been obtained for three mixtures of CH4 and C2Hg from 100 K to 320 K at

pressures to 35 MPa. When combined with previous data on pure CH4 and C2H5 , a heat capacity data base consisting of five compositions has been assembled

for development and testing of theoretically based predictive models. These

results are of immediate relevance since the CH4 4- C2Hg binary system is the

most important binary system in the natural gas industry. Also isochoric

heat capacity data have been measured for N2 + O2 + Ar (air) from 64 to 300 K

at pressures to 35 MPa. Cy measurements on three compositions of CO2 + C2H5

are in progress. The transient hot-wire apparatus has been used for

obtaining heat capacity, Cp, results over wide ranges of the fluid surface.

The natural gas industry is very interested in using sonic nozzles as

secondary flow measurement standards, but has been hampered by the lack of

accurate sound speed data upon which to base performance. Using a

cylindrical resonator, sound speed measurements have been made on twelve

gaseous binary mixtures of natural gas components, with methane as the major

constituent, and on four multicomponent mixtures simulating compositions of

industrial importance. These measurements cover a temperature range from 250

K to 350 K at pressures to 10 MPa. These results represent the only accurate

sound speed measurements for gaseous mixtures other than air. These data are

being used to develop a highly accurate predictive model for sound speeds in

natural gas and similiar mixtures.

A new spherical resonator is being constructed for wide-range sound

speed measurement from 80 K to 400 K at pressures to 10 MPa. This apparatus,

which will greatly expand our existing capabilities, will require innovative

development of transducers suitable for high temperatures and high pressures.

The data obtained from this apparatus will aid in the advancement of flow

metering and the development of predictive models

87
Transport Property Measurements . Correlations . and Theory

D.E. Diller, H.M. Roder, R.A. Perkins, D.G. Friend, J.C. R.ainwater, J.F. Ely,

M.L. Huber

Collaborators: C.A. Nieto de Castro (Lisbon University), W.A. Wakeham

(Imperial College), A. Laesecke (University of Siegen) , L.J. Van Poolen

(Calvin College)

In recent years industry has become increasingly aware that transport

properties play a significant role in process design and that accurate

knowledge of these properties can lead to substantial economic benefit. Our

work on transport properties of fluids encompasses the development of new

measurement techniques, the utilization of advanced apparatus to obtain

accurate data, the correlation of available transport property data, studies

of kinetic and transport theory, and the development of wide-range predictive

models for transport properties. Measurements of viscosity and thermal

conductivity are vital to complete the data base needed by the design

engineer and correlator and are a necessary adjunct to PVT and thermodynamic

properties. Further, the study of the transport coefficients is interesting

from a scientific standpoint as it demonstrates the behavior of a fluid not

in equilibrium.

We have an ongoing program to measure the viscosities of dense fluids

and fluid mixtures, from 80 K to 700 K, with pressures to 35 MPa, using two

different piezoelectric quartz crystal viscometfers. Our new high temperature

viscometer has recently been performance tested with measurements up to 50

MPa. Measurements on ethane, carbon dioxide, and their mixtures have been

completed. The low temperature viscometer has recently been used to obtain

viscosity data for liquid toluene and R-13. These data have again

demonstrated the power of examining the dependence of the fluidity

(viscosity" ^) of liquids on molar volume, and using this representation as a

simple method for correlating viscosity data for liquids.

For accurate thermal conductivity measurements the transient hot-wire

technique is recognized as state-of-the-art. Our low temperature hot-wire

apparatus covers temperatures from 80 K to 330 K at pressures up to 70 MPa.

During the past year we have concentrated on obtaining results for the

thermal diffusivity and the specific heat, Cp, along with the thermal

conductivity, using the transient hot-wire apparatus. So far we have carried

out measurements for argon and nitrogen in the low temperature apparatus with

an average uncertainty of 5% in Cp and less than 1% in the thermal

conductivity. In addition, a new high temperature transient hot-wire thermal

conductivity apparatus has been developed. It operates at temperatures

between 300 K and 775 K with pressures up to 70 MPa. After testing with

argon and nitrogen, measurements of standard reference quality are planned on

toluene and benzene.

We are completing new correlations for the thermal conductivity and

viscosity of methane, ethane, propane, and argon. Dilute gas data are

represented with theoretically based kinetic theory expressions. The

critical enhancement contribution to the thermal conductivity has also been

modeled with an expression with strong theoretical foundation. Finally, the

88
excess contributions for both transport coefficients have been described with

polynomial functions that represent the data within experimental uncertainty.

Analogous studies for ethane, propane, and the butanes are in progress. The

transport properties of binary mixtures of methane and ethane have been

studied experimentally in this laboratory; correlations of the thermal

conductivity and viscosity surfaces have been completed.

There is an ongoing effort to develop an improved theory for the

critical enhancement in the thermal conductivity of mixtures, which has been

observed experimentally in this laboratory. Finally, we have in recent years

developed the first successful microscopic theory of the initial density

corrections to viscosity and thermal conductivity. Calculations of

generalized collision integrals have been extended to lower reduced

temperatures and show good agreement with recent data for benzene and

methanol vapor. In addition, a new version of the TRAPP (Transport Property

Prediction) model has been developed which substantially improves the

prediction of mixture viscosity and thermal conductivity. Finally,

nonequilibrium molecular dynamics simulations are being carried out to form

the basis for a corrected Enskog theory of fluid transport.

Neutron Scattering

H.J.M. Hanley, G.C. Straty

Collaborators: J. Hayter*, C. Glinka**

N. Clark (University of Colorado) and D. Aastuen (University of Colorado)

This work is an experimental part of a large-scale program in our

Division to study complex liquids. It is carried out in conjunction with

parallel theoretical work on the structure of liquids and is concerned with

the similarities and differences between "simple" and "complex" fluids. The

specific objective is to examine long-range correlative or collective

molecular motion in the liquid via the structure factor, S(Q), using neutron

diffraction. Test systems have included glycerol and a suspension of latex

spheres in water. Glycerol was selected because it can be made to exhibit

characteristics ranging from those of the most simple to those of very

complex fluids by varying the temperature. Latex suspensions were used to

obtain benchmark data in preparation for forthcoming measurements on these

systems under shear. Such data also offer a unique opportunity for testing

theoretical models since the interparticle potential is well characterized,

and its strength can be "tuned" by the introduction and variation of ion

concentrations in the solution.

Specific tasks carried out during the past year were: (a) preliminary

measurements of the change in S(Q) of very viscous glycerol due to shear

using a newly constructed shearing apparatus and the NIST SANS (small angle

neutron scattering) and BT6 spectrometers; (b) measurements of S(Q) of

carefully prepared latex suspensions of various concentrations using the NIST

SANS spectrometer and the newly installed cold neutron source (the latter

samples were found to exhibit long range solid- like correlations at high

concentrations); and (c) completion and preparation for testing of a

versatile automated general purpose shearing apparatus for the study of

fluids under shear using neutron scattering. With regard to item (c)

,

89
results from these apparatus will be most instructive and essential to

understanding the microstructure of liquids and to meet our objective of

differentiating between simple and complex liquids. Furthermore, the cells

will upgrade the capability of the NIST reactor facility to handle fluids in

nonequilibrium. There is strong industrial (and biological) interest in

shearing equipment.

*Oak Ridge National Laboratory **NIST Institute for Materials Science

and Engineering

Non-Newtonian Fluid Behavior

H.J.M. Hanley, J.C. Rainwater, M.L. Huber

Collaborators: D.J. Evans, J.P. Morriss (Australian National University),

S. Hess (Berlin Technical University)

This program addresses theoretical problems related to the overall goal

of studying complex liquids. The work is carried out in conjunction with

parallel experimental work on neutron scattering and the structure of liquids

and is concerned with the similarities and differences between so-called

"simple" (e.g., argon, nitrogen) and "complex" (e.g., polymers, highly

branched hydrocarbons, hydrogen-bonded liquids) fluids. It was largely

motivated by the observation from computer simulation that simple liquids can

display rheological or non-Newtonian characteristics usually only associated

with liquids of very complex structure. In this context, it is preferable to

classify liquids in terms of a relaxation time of the fluid's microstructure.

Simple liquids have relaxation times of the order of 10 s, while for

complex liquids, the time is one second or greater.

There is a connection of this work to the goal of predicting fluid

properties and behavior. Prediction procedures for complex liquids are

largely adapted from methods developed for simple liquids, incorporating

improvements in a systematic manner based on an understanding of the

shortcomings of the methods.

The differences between isomers such as isobutane and normal butane have

been investigated using computer simulation. These isomers exhibit polymeric

behavior, and the results to date indicate that isobutane is viscoelastic.

Work on the rheological characteristics of simple fluids is continuing with a

re-examination of earlier Weissenberg effect calculations and a re-assessment

of the importance of shear dilatancy and finite compressibility. The radial

distribution function and structure factor have been calculated as explicit

vector functions in two dimensions and by using an expansion in moments or

spherical harmonics in three dimensions. A technique has been developed to

measure the structure factor of a two-dimensional liquid by transferring the

coordinates of the particles in a model liquid to photographic film, which is

then regarded as a scattering medium for laser light. Statistical noise can

be largely removed by spline- smoothing without changing the three-dimensional

structure factor in the physically important regions. The three-dimensional

90
structure factor has been compared with light scattering experiments on

sheared colloidal suspensions, and the essential qualitative features of

those experiments are reproduced correctly.

Other recent work includes : study of the effect of shear on the pair

correlation function of a liquid through tensor rank four, and derivation and

testing of a theory to predict the correlation function; continued work on

the development of computer simulation programs to simulate liquids under

shear and to show their relationship to experiment; and continued study of an

exactly solvable weak potential model under a flow field more general than

planar Couette flow.

SUBSECOND THERMOPHYSICS PROGRAM

Thermophvsical Measurements bv Dynamic Methods

A. Cezairliyan, A.P. Miiller, R.F. Chang, R.A. MacDonald, J.L. McClure,

G.M. Foley, P.J. Giarratano,* T. Baba (Guest Researcher)

The goal of this program is to develop and utilize techniques capable of

highly accurate measurements of thermal, optical, and electrical properties

of technically important materials at high temperatures using very high

heating rates. Experimental capabilities include millisecond techniques that

allow measurements of heat capacity, thermal expansion, electrical

resistivity, phase transition points, and latent heats; microsecond

techniques for measuring thermophysical properties at heating rates of 10^ - 10® K/s ; and millisecond techniques for such measurements in a microgravity

environment. Plans for the immediate future include the development of

dynamic techniques for measurements on nonconducting materials and

theoretical studies relevant to dynamic measurement techniques.

Research is under way to develop a system for the measurement of

thermophysical properties of electrically conducting liquids at high

temperatures (above 2000 K) in a microgravity environment. Efforts were

concentrated in the study of the geometrical stability of the liquid specimen

when heated rapidly by the passage of an electrical current pulse through it

in a microgravity environment. Diagnostic experiments were performed on

aircraft operated by NASA. The experiments on board the aircraft were

conducted by P. Giarratano. Excursions in the liquid phase could be seen

from the results of the high-speed films and the pyrometric recordings. In

order to improve the geometrical stability of the specimen, a triaxial

configuration for the specimen and the current leads was studied, an

experimental chamber was constructed, and experiments were conducted in

aircraft. The results of the experiments with the triaxial configuration

indicate the feasibility of measuring surface tension near the melting point

of the specimen. The surface tension of copper has been measured with this

new method. Work in this direction will continue.

The laser-pulse thermal diffusivity system, which became operational a

year ago, was used to perform definitive measurements on graphite in the

range 1500-2500 K. The results indicate a very high degree of

91
reproducibility (better than 1%) and suggest that the system can be used to

obtain accurate data, on both electrically conducting and nonconducting

materials, with implications to develop Standard Reference Materials for

thermal diffusivity at high temperatures.

A recently developed microsecond- resolution pulse heating system was

used to measure the heat of fusion of molybdenum in an effort to obtain

accurate thermophysical properties data on refractory metals, in their solid

and liquid phases, at high temperatures, in ground-based experiments.

^Chemical Engineering Science Division

5. PUBLICATIONS

Amar, J.G., Sullivan, F.E. and Mountain, R.D. , A Monte Carlo study of growth

in the two-dimensional spin-exchange kinetic Ising model, Phys . Rev.,

Vol . B37 , No. 1, pp. 196-208 (Jan. 1988).

Baltatu, M.E., Hanley, H.J.M. and Olien, N.A. , Taking the measure of

thermophysical properties data bases, Mech. Eng., Vol. 109, No. 64, p.

109 (Dec. 1987).

Berg, R.F. and Moldover, M.R. , Critical exponent for the viscosity of

four binary liquids, J. Chem. Phys., Vol. 89, pp. 3694-3704 (1988).

Bretz, M. , Shapiro, M.L. and Moldover, M.R.

,

Spherical acoustic

resonators in the undergraduate laboratory, Am. J. Phys. (submitted).

Brown, T.S., Kidnay, A.J. and Sloan, E.D., Vapor-liquid equilibria in the

carbon dioxide -ethane system, Fluid Phase Equilibria, Vol. 40, pp. 169-

184 (1988).

Bruno, T.J., Catalytic cracking detector for gas chromatography, NIST J.

Res., Vol. 92, No. 4, p. 261 (1987).

Bruno, T.J., Solvent free injection in SFC using sintered glass deposition,

NIST J. Res., Vol. 93, No. 6, p. 1 (1988).

Bruno, T.J., Supercritical fluid chromatograph for physicochemical studies,

NIST J. Res. (in press).

Bruno, T.J., Supercritical fluid chromatograph for physicochemical studies:

binary diffusion coefficients, Spec. Proc. Issue, Int. J. Thermophys

( in press)

Bruno, T.J., Martire, D.E., Reister, R. and Poe, D. , Spatial and temporal

considerations in gas, liquid and supercritical fluid chromatography:

applications to supercritical fluid chromatography, J. Chromatogr. (in

press)

92
Bruno, T.J. and Outcalt, S.L., Hydrogen component fugacity coefficients in

binary mixtures with isobutane: temperature dependence, Spec. Proc.

Issue, Int. J. Thermophys. (in press).

Bruno, T.J. and Schroeder, J. A., Hydrogen component fugacities in binary

mixtures with carbon monoxide: temperature dependence, Int. J.

Thermophys., Vol. 9, No. 4, p. 525 (1988).

Bruno, T.J. and Svoronos, P.D.N., book, Handbook of Basic Tables for Chemical

Analysis, CRC Press, Boca Raton, FL (1988).

Cezairliyan, A., Pulse calorimetry, Chap. 9 in book, Specific Heat of Solids,

Hemisphere Pub. Corp. (1988).

Cezairliyan, A., Volume coordinator, book, Specific Heat of Solids,

Hemisphere Pub. Corp. (1988).

Cezairliyan, A. and McClure, J.L., Heat capacity and electrical resistivity

of liquid niobium near its melting temperature, Int. J. Thermophys.,

Vol. 8, No. 6, pp. 803-808 (Nov. 1987).

Cezairliyan, A. and Miiller, A.P., Measurement of the radiance temperature

(at 655 run) of graphite at its triple point by a pulse-heating

technique, Spec. Proc. Issue, Int. J. Thermophys. (submitted).

Cezairliyan, A. and Miiller, A.P., A dynamic technique for thermophysical

measurements at high temperatures in a microgravity environment, Spec.

Proc. Issue, Int. J. Thermophys. (submitted).

Clark, E.J. and Hoffman, J.D., Crystallization and fibril formation in

polymers, Spec. Proc. Issue, Int. J. Thermophys. (submitted).

Diller, D.E. and Frederick, N.V.

,

Torsional piezoelectric crystal viscometer

for compressed gases and liquids, Spec. Proc. Issue, Int. J. Thermophys.

(submitted)

Diller, D.E., Van Poolen, L.J. and dos Santos, F.V.

,

Measurements of the

viscosities of compressed gaseous and liquid carbon dioxide + ethane

mixtures, J. Chem. Eng. Data, Vol. 33, No. 4, pp. 460-464 (1988).

Ely, J.F. and Huber, M.L.

,

Computer simulation of the excess chemical

potential and partial molar volumes in Lennard- Jones mixtures with large

size ratios, Mol. Phys . (in press).

Ewing, M.B., Mehl, J.B., Moldover, M.R. and Trusler, J.P.M., Microwave

measurements of the thermal expansion of a spherical cavity, Metrologia

(submitted)

Flanigan, D.A.

,

Yesavage, V.F., Cerise, K.S., Niesen, V.G. and Kidnay, A.J.,

Enthalpy of Quinoline Between 291 and 655 K at Pressures to 10342 kPa,

J. Chem. Thermodyn. , Vol. 20, pp. 109-117 (1988).

93
Fox, J.R. and Storvick, T.S., A field-space conformal solution method, Spec.

Proc. Issue, Int. J. Thermophys . (submitted).

Friend, D.G., The viscosity surface for mixtures of methane and ethane, Spec.

Proc. Issue, Int. J. Thermophys. (submitted).

Friend, D.G., Ely, J.F. and Ingham, H. , Thermophysical properties of methane,

J. Phys . Chem. Ref. Data (submitted).

Gallagher, J.S. and Morrison, G. , Modelling impurity effects in fluids and

fluid mixtures, J. Chem. Eng. Data, Vol. 32, p. 412 (1987).

Gallagher, J.S. and Levelt Sengers, J.M.H., The modelling of the

thermodynamic properties of sodium chloride in steam through the case of

extended corresponding states, Int. J. Thermophys. (submitted).

Gallagher, J.S., McLinden, M.O. and Morrison, G., Thermodynamic diagrams for

refrigerant mixtures, ASHRAE Trans, (submitted).

Giarratano, P.J., Arp, V.D., Owen, R.B., Cezairliyan, A. and Miiller, A.P.,

Transient heat transfer and thermophysical properties measurements in

low gravity, in book, Low Gravity Science, Vol. 67, pp . 55-68 (1987),

Sci. and Tech. Series (Am. Astronaut. Soc. by Univelt, San Diego, CA)

Guillot, B. , Mountain, R.D. and Birnbaum, G. , Theoretical study of the

three-body absorption spectrum in pure rare gas fluids, Mol. Physics,

Vol. 64, No. 4, pp. 747-757 (1988).

Hanley, H.J.M., Anisotropic structure in a simple liquid, KINAM (Mexico) (in

press)

Hanley, H.J.M. and Evans, D.J., Non-Newtonian molecular dynamics and

thermophysical properties, Spec. Proc. Issue, Int. J. Thermophys.

(submitted)

Hanley, H.J.M. , Meyers, G.W. , White, J.W. and Sloan, E.D. , The

tetrahydrofuran hydrate in D2 0, J. Phys. Chem. (in press).

Hanley, H.J.M., Morriss, G.P., Welberry, T.R. and Evans, D.J., Shear induced

anisotropy in two-dimensional liquids, Physica, Vol. 149A, pp . 406-431

(1988) .

Hanley, H.J.M., Rainwater, J.C., Evans, D.J. and Hood, L. , Shear dilatancy

and finite compressibility in a dense non-Newtonian liquid, Proc. Tenth

Int. Cong. Rheology, P.H.T. Uhlherr, ed. , Vol. 1, pp . 386-388, (1988),

Australian Society of Rheology, Sydney, Australia.

Hanley, H.J.M., Rainwater, J.C. and Huber, M.L, Prediction of shear viscosity

and non-Newtonian behavior in the soft sphere liquid, Spec.- Proc. Issue,

Int. J. Thermophys. (submitted).

94
Hanley, Welberry, T.R. , Evans, D.J. and Morriss, G.P. , Local order in

a dense liquid, Phys . Rev., Vol. A38, No. 3, pp. 1628-1632 (1988).

Harden, J.L. and Kayser, R.F., The effect of long range interfacial forces on

capillary wave dynamics of wetting layers on a liquid-vapor interface,

J. Colloid Interface Sci. (in press).

Hubbard, J.B. and McCammon, J.A., Electrophoretic light scattering from

macromolecular solutions and conformational dynamics, J. Chem. Phys.,

Vol. 87, No. 8, p. 4339 (1987).

Hubbard, J.B. and McQuarrie, D.A.

,

Mobility fluctuations and electrophoretic

light scattering from macromolecular solutions, J. Stat. Phys.

(submitted)

Hubbard, J.B. and Wolynes, P.G.

,

Theories of solvated ion dynamics, Chap, in

book, The Chemical Physics of Solvation, Part C, Solvation Phenomena in

Specific Physical, Chemical, and Biological Systems, R.R. Doganadze, et

al., eds., pp. 33-112 (1988), Elsevier Publishers, New York, NY.

Huber, M.L. and Ely, J.F., Extension of an improved one-fluid conformal

solution theory to real fluid mixtures with large size differences,

Spec. Proc. Issue, Int. J. Thermophys . (submitted).

Huber, M.L. and Jones, M.C.

,

A frequency response study of packed bed heat

transfer at elevated temperatures, J. Heat Mass Transfer, Vol. 31, No.

4, pp. 843-853 (1987).

Jacobsen, R.T., Beyerlein, S.W., Clarke, W.P., Rousseau, M. , Van Poolen, L.J.

and Rainwater, J.C., Thermodynamic properties of air on the dew and

bubble lines, Spec. Proc. Issue, Int. J. Thermophys. (submitted).

Jacobsen, R.T., Clarke, W.P., Penoncello, S.G. and McCarty, R.D.,

A thermodynamic property formulation for air from 60 K to 873 K at

pressures to 70 MPa, Spec. Proc. Issue, Int. J. Thermophys. (submitted).

Japas, M.L. and Levelt Sengers , J.M.H., Gas solubility and Henry's law near

the solvent's critical point, AIChE J. (submitted).

Jonah, D.A.

,

Kincaid, J.M. and Morrison, G. , A new method for correlating the

properties of dilute mixtures, J. Chem. Phys. (submitted).

Kayser, R.F., Wetting layers in electrolyte solutions, J. de Physique, Vol.

49, p. 1027 (June 1988).

Levelt Sengers, J.M.H., Solubility in near- and supercritical water, Proc.

EPRI Conf. on Cycle Chemistry in Fossil Plants, Seattle, WA, Aug. 30-

Sept. 1, 1988 (submitted).

Levelt Sengers, J.M.H., On the continuity of the gaseous and liquid states,

Nederlands Tydschrift voor Natuurkunde (submitted)

95
Levelt Sengers, Thermodynamic properties of aqueous solutions at high

temperatures - needs, methods, and challenges, Spec. Proc . Issue, Int.

J. Thermophys . (submitted).

Levelt Sengers, J.M.H., Aqueous solutions near the critical point of steam,

Proc. of the Int. Conf. on Thermodyn. of Aqueous Systems with Industrial

Applications, Airlie House, Warrenton, VA. (Dec. 1987) (in press).

Levelt Sengers, J.M.H. and Sengers, J.V., van der Waals-fund, van der Waals

laboratory and Dutch high-pressure science, Special Issue of Physica

(submitted)

Linsky, D. , Levelt Sengers, J.M.H. and Davis, H.A.

,

Semi -automated Burnett

PVT apparatus - properties of a geothermal working fluid, Proc. 5th

Symp. on Energy Eng. Sci., CONF-8706187 , pp. 26-36 (June 1987), Argonne

Nat ' 1 . Lab . , Argonne , IL

Linsky, D. , Levelt Sengers, J.M.H. and Gallagher, J.S., A semi -automated

Burnett facility - PVT of a geothermal working fluid mixture, Fluid

Phase Equilibria, Vol. 36, pp. 149-165 (1987).

MacDonald, R.A.

,

Computer model of a porous medium, Spec. Proc. Issue, Int.

J. Thermophys. (submitted).

MacDonald, R.A.

,

Cailanan, J.E. and McDermott, K.M.

,

Heat capacity of a

medium volatile bituminous premium coal from 300-520 K - comparison with

a high volatile bituminous nonpremium coal, J. Energy Fuels, Vol. 1, No.

6, pp. 535-540 (Nov. 1987).

McClure, J.L. and Cezairliyan, A., Microsecond-resolution electrical

measurements in high current discharges, Proc. of Workshop on Subsecond

Thermophysics, Int. J. Thermophys. (submitted).

Magee, J.W. and Ely, J.F., Isochoric (p,v,T) measurements on CO2 and

(0.98 CO2 + 0.02 CH4) from 225 to 400 K at pressures to 35 MPa, Int. J.

Thermophys., Vol. 9, No. 4, pp. 547-557 (1988).

Mayrath, J.E. and Magee, J.W., Molar heat capacity (Cv) measurements on

[XCH4 + (l-x)C2H£] from 100 to 320 K at pressures to 35 MPa, J. Chem.

Thermodyn. (in press).

Miiller, A.P., Theory of specific heat of solids, in Chap.l in book, Specific

Heat of Solids, Vol. 1-3, pp. 1-89 (1988), Hemisphere Pub. Corp.

,

New

York, NY.

Miiller, A.P. and Cezairliyan, A., Thermal expansion of tungsten in the range

1500-3600 K by a transient interferometric technique, Spec. Proc. Issue,

Int. J. Thermophys. (submitted).

Miiller, A.P. and Cezairliyan, A., A dynamic technique for measuring surface

tension at high temperatures in a microgravity environment, Spec. Proc.

Issue, Int. J. Thermophys. (submitted).

96
Miiller, A.P. and Cezairliyan, A., Thermal expansion of niobium in the range

1500-2700 K by a transient interferometric technique, Spec. Proc . Issue,

Int. J. Thermophys . , Vol. 9, No. 2, pp . 195-203 (Mar. 1988).

Moldover, M.R. , Acoustic and microwave resonances applied to measuring the

gas constant and the thermodynamic temperature, IEEE Trans. Instrum.

Meas. (submitted).

Moldover, M.R. and Rainwater, J.C., Interfacial tension and vapor-liquid

equilibria in the critical region of mixtures, J. Chem. Phys . , Vol. 88,

No. 12, pp. 7772-7780 (June 1988).

Moldover, M.R. and Trusler, J.P.M., Accurate acoustic thermometry I: the

triple point of gallium, Metrologia, Vol. 25, pp . 165-187 (May 1988).

Moldover, M.R.

,

Trusler, J.P.M, Edwards, T.J., Mehl, J.B. and Davis, R.S.,

Measurement of the universal gas constant R using a spherical acoustic

resonator, J. Res. NBS , Vol. 93, No. 3, pp . 85-114 (Mar. -Apr. 1988).

Moldover, M.R.

,

Trusler, J.P.M.

,

Edwards, T.J., Mehl, J.B. and Davis, R.S.,

Measurement of the universal gas constant R using a spherical acoustic

resonator, Phys. Rev. Lett., Vol. 60, No. 4, pp. 249-252 (Jan. 1988).

Morrison, G. , Modelling aqueous solutions near the critical point of water,

J. Solution Chem. (submitted).

Morrison, G. and McLinden, M.O.

,

Modelling refrigerant mixtures with

hard-sphere equations of state, AIChE J. (submitted).

Morrison, G. and Pegg, I.L., New experiments on the Langmuir film balance,

Fifth Symp. on Energy Eng. Sci., CONF. -8706187 , pp . 45-51 (June 1987)

Argonne Nat'l. Lab., Argonne, IL.

Mountain, R.D.

,

Simulation study of light scattering from soot agglomerates,

in book, Computer Simulation Studies in Condensed Matter Physics:

Recent Developments, D.P. Landau and H.B. Schutter, eds .

,

Springer Proc.

Phys. (submitted).

Mountain, R.D.

,

Molecular dynamics investigation of expanded water at

elevated temperatures, J. Chem. Phys. (submitted).

Mountain, R.D. and Birnbaum, G. , Molecular dynamics study of intercollisional

interference in collision induced absorption in compressed fluids, J.

Chem. Soc. Faraday Trans. 2, Vol. 10, No. 83, pp. 1791-1799 (1987).

Mountain, R.D. and Morrison, G. , Molecular dynamics study of liquid CCI 2 F2

and CC1HF2 , Mol. Phys., Vol. 64, No. 1, pp. 91-95 (1988).

Mountain, R.D. and Mulholland, G.W.

,

Light scattering from simulated smoke

agglomerates, Langmuir (submitted).

97
Mountain, R.D. and Thirumalai, D. , Molecular dynamics study of glassy and

supercooled states of a binary mixture of soft spheres, Phy. Rev., Vol.

A3 6 , No. 7, pp. 3300-3311 (Oct. 1987).

Mountain, R.D., Thirumalai, D. and Kirkpatrick, T.R.

,

Ergodic behavior in

supercooled liquids and in glasses, Phys . Rev. A. (submitted).

Mulholland, G.W., Samson, R.J., Mountain, R.D. and Ernst, M.H.

,

Cluster size

distribution for free molecular agglomeration, J. Energy Fuels, Vol. 2,

pp. 481-486 (1988).

Nielsen, G.C., Morrison, G., McLinden, M.O. and Levelt Sengers , J.M.H., Use

of computer algebra to locate critical loci of fluid mixtures, AIChE J.

(submitted)

Niesen, V.G. and Yesavage, V.F., Vapor-liquid equilibria for mcresol/quinoline at temperatures between 523 and 598 K, J. Chem. Eng.

Data, Vol. 33, p. 138 (1988).

Niesen, V.G. and Yesavage, V.F., Vapor-liquid equilibria for mcresol/tetralin and tetralin/quinoline at temperatures between 523 and

598 K, J. Chem. Eng. Data, Vol. 33, p. 253 (1988).

Nieto de Castro, C.A., Taxis, B., Roder, H.M. and Wakeham, W.A.

,

Thermal

diffusivity measurements by the transient hot wire technique: a

reappraisal, Int. J. Thermophys . , Vol. 9, No. 3, pp . 293-316 (1988).

Olchowy, G.A. and Sengers, J.V., A simplified representation for the thermal

conductivity of fluids in the critical region, Spec. ProcIssue, Int.

J. Thermophys. (submitted).

Olien, N.A.

,

Thermophysical properties of fluids, section in book, Handbook

of Fluids and Fluid Machinery, John Wiley and Sons (in press).

Olien, N.A.

,

Book Review: Thermodynamic Properties of Helium, Nitrogen,

Methane, Ethane, Oxygen, Air, Ethylene, Refrigerants, Neon, Argon,

Krypton, and Xenon (translation from Russian), T.B. Selover, ed.

,

Hemisphere Pub. Corp., New York, NY, Applied Meehan. Rev., Vol. 41,

p. B119 (1988).

Peters, C.J., de Swaan Arons, J., Levelt Sengers, J.M.H. and Gallagher, J.S.,

Global phase behavior of mixtures of short and long n-alkanes, AIChE J.,

Vol. 34, No. 5, pp. 834-839 (May 1988).

Rainwater, J.C., Asymptotic expansions for constant-composition dew-bubble

curves near the critical locus, Spec. Proc. Issue, Int. J. Thermophys.

(submitted)

Rainwater, J.C., Vapor-liquid equilibrium of binary mixtures in the extended

critical region I. thermodynamic model, Fluid Phase Equilibria

(submitted)

98
Rainwater, J.C., Hanley, H.J.M. and Hess, S., The static structure factor of

a soft sphere liquid under shear, Phys . Lett., Vol. A126, pp . 450-454

(Jan. 1988)

Rainwater, J.C. and Jacobsen, R.T. , Vapor-liquid equilibrium of nitrogenoxygen mixtures and air at high pressure, Cryogenics, Vol. 28, pp . 22-31

(Jan. 1988).

Roder, H.M. and Perkins, R.A. , Relation between wire resistance and fluid

pressure in the transient hot wire method, NIST J. Res. (in press).

Roder, H.M. , Perkins, R.A. and Nieto de Castro, C.A., Experimental thermal

conductivity, thermal diffusivity and specific heat values of argon and

nitrogen, NIST IR 88-3902 (in press).

Roder, H.M. and Nieto de Castro, C.A.

,

Measurement of thermal conductivity

and thermal diffusivity of fluids over a wide range of densities, Proc.

Twentieth Int. Conf. on Thermal Conductivity, D.P.H. Hasselman, ed.

,

Thermal Conductivity 20, Blacksburg, VA (Oct. 20-21, 1987).

Romig, K.D.

,

Jr. and Hanley, H.J.M.

,

Phase equilibria from the one-fluid

model, Cryogenics (in press).

Schmidt, J.W., The structure of a fluid interface near the critical point,

Phys. Rev., Vol. A38, pp. 567-570 (July 1988).

Schmidt, J.W., Systematics of wetting and prewetting, J. Colloid Interface

Sci.

,

Vol. 122, p. 575 (1988)

Sherman, G.J., Magee, J.W. and Ely, J.F., PVT relationships in a carbon

dioxide rich mixture with ethane, Spec. Proc. Issue, Int. J. Thermophys

(submitted)

Sridharan, S., McCammon, J.A. and Hubbard, J.B., Diffusion-controlled

reactions of ions in fluctuating ionic atmospheres, J. Chem. Phys.

(submitted)

Stiles, P.J., Kagan, M. and Hubbard, J.B., On the Couette -Taylor instability

in ferrohydrodynamics , J. Colloid Interface Sci., Vol. 120, No. 2,

p. 430 (1987).

Storvick, T.S. and Fox, J.R., A field-space conformal solution method: binary

vapor- liquid behavior, Spec. Proc. Issue, Int. J. Thermophys.

(submitted)

Straty, G.C., Ball, M.J. and Bruno, T.J., PVT of toluene at temperatures to

673 K, J. Chem. Eng. Data, Vol. 33, pp . 115-117 (1988).

Straty, G.C. and Hanley, H.J.M., Preliminary studies of neutron diffraction

from sheared d- glycerol, Proc. of the Sixth Symp. on Energy Engineering

Science, CONF-8805106 (May 4-6, 1988), Argonne Natl. Lab., Argonne , IL.

99
Straty, G.C.

,

Hanley, Glinka, C.J. and Hayter, J.B., Low-Q neutron

diffraction from supercooled d-glycerol, Mol. Phys., Vol. 62, No. 5, pp.

1165-1174 (1987).

Van Poolen, L.J., Representation of binary mixture liquid-vapor equilibria by

means of critical isochores, Spec. Proc. Issue, Int. J. Thermophys

(submitted)

Weber, L.A.

,

Vapor pressures and gas phase PVT data for

1 , 1 , 1 , 2-tetrafluoroethane , Spec. Proc. Issue, Int. J. Thermophys.

(submitted)

Weber, L.A.

,

A simple apparatus for vapor-liquid equilibrium measurements

with data for the binary systems of carbon dioxide with normal and

isobutane, J. Ghem. Eng. Data (submitted).

Yesavage, V.F., Niesen, V.G.

,

Flanigan, D.A.

,

Flanigan, J.W., Sandarusi, J.A.

and Kidnay, A.J., Enthalpy of ternary mixtures of quinoline/

1-methylnaphthalene/trans-decalin and quaternary mixtures of

m-cresol/quinoline/1-methylnapththalene/trans- decal in between 291 and

650 K at pressures of 207 and 10342 kPa, J. Chem. Eng. Data (in press).

Younglove, B.A. and Ely, J.F., Thermophysical properties of fluids, II.

methane, ethane, propane, isobutane, and normal butane, J. Phys. Chem.

Ref. Data, Vol. 16, No. 4, pp. 577-798 (1987).

6. CONFERENCES AND WORKSHOPS

CONFERENCES

Tenth Symposium on Thermophysical Properties, Gaithersburg, MD, June 20-23,

1988. Organized and chaired by A. Cezairliyan and J.V. Sengers.

Second U.S. -Japan Joint Conference on Thermophysical Properties,

Gaithersburg, MD, June 23, 1988. Organized and chaired by A. Cezairliyan,

J.V. Sengers, and A. Nagashima of Keio University, Japan.

American Institute of Chemical Engineers 1988 Summer National Meeting, August

21-24, 1988, Denver, CO. Neil A. Olien, Meeting Program Chairman. In terms

of number of sessions, papers presented, and attendance, this was the largest

Summer meeting in AIChE history.

WORKSHOPS

First Workshop on Subsecond Thermophysics, Gaithersburg, MD, June 20-21,

1988. Organized and chaired by A. Cezairliyan.

Workshop on Thermophysical Property Data Needs for Ozone-Safe Refrigerants,

Gaithersburg, MD, September 22, 1988. Jointly sponsored by the NIST Center

for Building Technology and the NIST Center for Chemical Engineering.

100
TECHNICAL ACTIVITIES

OF THE

CHEMICAL PROCESS METROLOGY DIVISION

H.G. Semerjian, Chief

1. INTRODUCTION

The research of the Chemical Process Metrology Division is focussed on

the development of new measurement techniques for process sensing,

diagnostics, and control. Particular emphasis is placed on measurement

methods and data that are needed for process control in the chemical,

biochemical, and related industries.

The approach has been to conduct research on new experimental methods

and engineering science underlying reliable measurements and data bases; this

work is complemented with theoretical and computational modeling of processes

under investigation and transport processes affecting sensor performance.

The research is aimed at (a) investigation of new engineering and scientific

principles which can be utilized for measurement of physical or chemical

quantities in industrial processes, (b) development of accurate measurement

methods and measurement standards for industry, and (c) providing primary

calibration services for a wide segment of the U.S. industry and the

scientific research community. These measurements include temperature,

velocity, flow rate, humidity, composition and concentration, pH, particle

size and number density, volume fraction, and other quantities of interest in

multiphase reacting and nonreacting process streams. Emphasis is on the

development of on-line, and where possible in- situ, measurement techniques

needed for control of industrial processes.

Current projects address several of the research areas mentioned above.

An extensive data base has been developed on orifice discharge coefficients

to improve the accuracy of flow metering in gaseous and liquid streams. This

work represents a major contribution towards equity in the domestic and

international trade of oil and gas, as well as other commodities. Other

projects on vortex shedding flowmeters and installation effects (supported by

industrial consortia) have also resulted in experimental data critically

needed for improvement of the current flowrate measurement technology.

Electromagnetic field methods have been successfully applied for measurement

of solids fraction in slurry flows, and a prototype sensor is currently

undergoing field tests. Electrochemical techniques have also been used for

measurement of diffusion coefficients in liquids and are now being extended

to porous media. Optical techniques have been developed, particularly for

measurements in single phase and multiphase reacting flows. They have been

successfully applied to provide data on temperature, gas composition,

particle size distribution, and gas/solid reaction rates in flames, fluidized

bed reactors (FBR) , plug flow reactors (PFR) and other high temperature

reacting flows. Solid-state sensors, utilizing iridium oxide and tin oxide,

are being developed for pH and chemical composition measurements in process

streams. Thin film thermocouples have been demonstrated to provide

temperature measurements in harsh environments (e.g., in ceramic engines)

101
with good temporal resolution. Finally, computational models have been

developed to simulate chemically reacting flows, formation and oxidation of

particles, and transport processes in high temperature reacting flows.

Future trends in the Chemical Process Industry are directed toward

transition to higher-value added products, increased biochemical production

of pharmaceuticals, foodstuffs, specialty chemicals, and fuels, and increased

production of chemicals and materials for microelectronics, photonics, and

high temperature applications. The Division's programs are being developed

to address many of the critical technical problem areas and measurement needs

within these emerging technologies. Several new and exciting projects are

underway to provide new measurement methods for biochemical reactors - optical diagnostic techniques have been demonstrated as useful tools for

substrate, product, and cell concentration measurements in fermentation

systems; an electrophoretic light scattering technique is being developed as

a new tool to monitor protein transport processes; electric field effects

will be investigated to study their role in transport through biological

membranes and possible use in bioreactors. Techniques developed for

particulate measurements in flames are being extended to study formation of

silica particles; these techniques will provide data needed to improve

chemical processes used in the fabrication of optical fibers. Laser

diagnostic techniques, used for temperature and gas phase composition

measurements in flames, will be extended to study chemical vapor deposition,

laser enhanced CVD, plasma etching, and other processes used in

microelectronics fabrication. Laser based diagnostic techniques are also

expected to make a significant contribution towards optimization of powder

atomization processes, one of the most promising processes in metals

processing and for production of high temperature ceramics. Finally,

existing high temperature reactor facilities (FBR, PFR) have been modified to

study pyrolysis and combustion of chlorinated hydrocarbons. This project

will provide critically needed data to address a major national concern-

disposal of hazardous wastes. Developments in these emerging areas of

research will be closely monitored, and the Division's research priorities

will be modified to meet anticipated measurement and data needs.

The Division has been striving to develop and maintain all possible

forms of technology transfer. Industrial consortia have been one of the most

successful forms of this transfer and the Flowmeter Installation Effects

Consortium has attracted a substantial membership. There are also

collaborative efforts with several instrumentation companies, who are

interested in utilizing NIST-developed technology toward development of

commercial instruments. Details of these interactions are reported in the

main body of this report.

The Division has continued providing calibration services in mass and

volumetric flow, air speed, humidity, volume, and liquid density to a variety

of clients across the country. The recent upgrading of these facilities will

make it possible to serve the U.S. industry more effectively.

102
2. GOAL

Within the framework of the Center, the Chemical Process Metrology

Division's main concern is the science of measurement in homogeneous and

heterogeneous flow systems with and without chemical reaction.

The goal of the Division is to provide the chemical and related

industries and other government agencies with the measurement techniques,

fundamental data, and the underlying scientific principles pertinent to

homogeneous and heterogeneous flows with and without chemical/biochemical

reactions at ambient and elevated temperatures. A key element in the pursuit

of this goal is the study of surface, transport, and kinetic phenomena in the

environment of sensing and diagnostic tools.

Further, process measurement is the key component of any process control

loop, the proper function of which is essential to maintaining the highest

quality of manufactured goods and, in turn, the competitive edge of the U.S.

industry on domestic as well as foreign markets.

In parallel with its research work, the Division maintains state-ofthe-art calibration services for flowrate, volume, density, humidity and air

speed, thus providing industry and other government agencies with

traceability of their instrumentation to national standards and thus assuring

equity in domestic and international trade.

3. GROUP FUNCTIONS

The research activities of the Division are carried out within four Groups:

• Fluid Flow Group - G.E. Mattingly, Group Leader

The mission of the Fluid Flow Group is to study the fundamentals of

fluid flow with the aim of advancing the state-of-the-art in flow metrology

and of applying these principles toward improving and expanding the NIST flow

measurement capabilities, as needed, for single phase gases and liquids

(water and hydrocarbons) and multiphase systems (sand-water mixtures)

Research is primarily focused on flow phenomena in conduits as well as

in free surface flows in geometries pertinent to the technologies used in the

chemical and related industries.

The Fluid Flow Group maintains responsibility for the NIST fluid flow

rate and airspeed calibration services and for the maintenance and upgrading

of the relevant national standards. The Group is responsible for the

transfer of fluid flow measurement technology to industry, other government

agencies, and public institutions.

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• Multiphase Reacting Flows Group - A.K. Gaigalas, Group Leader

The mission of the Multiphase Reacting Flows Group is research on

multiphase flows at ambient and near-ambient temperatures with and without

chemical reactions. The ultimate purpose of this activity is to (1) provide

fundamental data, (2) develop improved measurement techniques for on-line

process diagnostics, and (3) develop mathematical models for improved

understanding and control of physical, chemical, and biochemical processes.

Particular emphasis is placed on the development of advanced diagnostic

techniques utilizing electromagnetic and acoustic fields and electrochemical

phenomena. Focus of the future activities of this Group will be on

biochemical processes.

The Multiphase Reacting Flows Group bears the responsibility for NIST

calibration services in liquid density and volume.

• High Temperature Reacting Flows Group - A. Macek, Group Leader

The High Temperature Reacting Flows Group conducts fundamental research

on chemically reacting flows, especially those with gas -solid reactions

involving solid particles either formed or entrained. The research includes

advanced optical, nonintrusive measurement techniques for high temperature

reactors such as combustors and fluidized bed reactors.

Particular emphasis is on the use of laser scattering and extinction

techniques for particle characterization, laser tomography for temperature

and composition measurements, laser induced fluorescence (LIF) for

composition measurements, and emission spectroscopy for temperature

measurement. The scattering/extinction techniques are being adapted to the

study of gas -solid chemical reactions relevant to chemical vapor deposition

and to ceramics and powder metallurgy.

A significant segment of the research activities in this group is the

extension of the LIF techniques to optical diagnostics of species (nutrients,

substrates, metabolic intermediates, and products) in biochemical reactors.

• Process Sensing Group - K.G. Kreider, Group Leader

The Process Sensing Group performs research directed toward the development of process sensors with particular emphasis on solid state sensors for

chemical species, humidity, and temperature. Reactive sputtering is used to

deposit films; a comprehensive surface analytical facility is used to characterize the surfaces of films and bulk materials where chemical reactions take

place.

For gas sensing, the focus of the research is on tin oxide films, while

iridium oxide forms the backbone of the work on ionic sensors. Furthermore,

thin film thermocouples deposited on metal, ceramic, and polymer substrates

are the subject of study.

104
The Process Sensing Group is responsible for providing the NBS

calibration services of humidity and for the maintenance of the humidity

national standard.

4. SELECTED PROJECT SUMMARIES

CALIBRATION SERVICES

Calibration and Test Services Performed

bv the Chemical Process Metrology Division

G.E. Mattingly, A.K. Gaigalas, K.G. Kreider

In the past year, the CCT calibration services have satisfied industry

and government requests for a number of metrological tasks in the areas of

fluid flowrate, liquid density and volume, air speed, and humidity

measurements. Additionally, the techniques and facilities for performing

these services have been assessed and are being upgraded so that the levels

of measurement uncertainty are better quantified and reported for publication

in the appropriate literature. In the specific calibration services offered

to U.S. industry, activities are summarized as follows:

Service Number of Items Calibrated

Flowrate

Volumetric Containers

Aerodynamic Devices

Reference Standard Hydrometers

Humidity

38 (30 for industry)

88 (81 for industry)

74 (54 for industry)

73 (73 for industry)

81 (78 for industry)

These calibrations generally establish a traceability link between the

standards of the respective calibration requester and the national standards

maintained by NIST. In this way, a basis for the assurance of all the

measurements produced in the requester's laboratories is provided.

Besides these services, a number of in-situ calibrations were performed

by NIST personnel in the customers' laboratories, providing improved

traceability links between actual installed instrumentation and the national

standards for these measurements.

FLUID FLOW GROUP

Fluid Flowrate Traceability

G.E. Mattingly

The Calibration Coordination Group (CCG) of the Department of Defense

(DoD) has initiated a metrological program to establish realistic

traceability for the fluid flowrate measurements made in the Primary

Standards Laboratories of the Army, Navy, and Air Force. This program is

105
focused on liquid hydrocarbon measurements because of the crucial role these

play in critical engine performance tests. Accordingly, CCG has set fluid

flowrate measurement accuracy improvement goals for their Primary Standards

Laboratories of ± 0.05% for liquids and ±0.1% for gases. The NIST/CCG

program to establish realistic flow measurement traceability is viewed as the

initial step in attaining these goals.

To initiate this program, NIST, with DoD flow metrologists , designed a

round robin flow measurement program tailored to DoD needs. Repeated initial

testing was conducted at NIST and a first round of testing was performed. To

date, the initial phase of this round robin testing program has successfully

produced tests in some twenty facilities; these include DoD, industrial, and

other national laboratories which were tested at DoD's request. This program

is being expanded to include larger meters and flowrates; it is planned to

expand the program to test laboratories using air as the flowing medium.

When such programs are fully established and are conducted on a continuing

basis, realistic traceability will be quantified among participant

laboratories. This will benefit the flowmetering community, both national

and international.

Flowmeter Installation Effects

G.E. Mattingly, T.T. Yeh

The increasing cost of feedstocks has necessitated flow measurements

with increased accuracy. Similar requirements also exist throughout the

continuous process industries where precise measurement and control are

essential to optimize productivity. Improvements are especially needed in

specifying metering installations in "nonideal" situations. High measurement

accuracy is sought for meters retrofitted into existing piping systems --not

originally designed for "ideal" meter installations. Currently, available

meter installation specifications give little or no guidance to attain

desired levels of performance. This program, which is being supported by an

Industry/Government Consortium, is designed to provide such guidance.

Experimental studies of pipe flows are being conducted at

NIST/Gaithersburg, using laser Doppler velocimetry (LDV) to study the

secondary swirling flows produced downstream of selected piping

configurations. To date, these results quantify pipeflow profiles for both

time -averaged and turbulent velocity components as well as swirl -angle and

power-spectral density distributions. Recently, the program has completed

the study of several elbow-out-of -plane configurations and a standard single

elbow configuration. To demonstrate that satisfactory performance can be

predicted for meters in "nonideal" installations, a turbine type meter and

several sizes of orifice type meters were successfully tested. Current

experiments focus on assessing flow conditioner effectiveness using LDV. In

this way, detailed results will be produced to determine what effect these

devices have on pipe flows.

106
The results of this program will improve fluid flowrate measurements

and, in turn, quality assurance, industrial productivity, and competitiveness

--both domestically and internationally. These activities are being

coordinated with other metering projects at CCT/Boulder and elsewhere. The

results of this research are being put directly into new U.S. flowmetering

standards

Supersonic Inert-Gas Metal Atomization

G.E. Mattingly, P.I. Espina, S. Ridder*, F. Biancaniello*

Metal atomization, the production of rapidly solidified fine powders

through the interaction of high pressure gas jets and liquid metal streams,

is an emerging technology that offers considerable promise for improved

industrial productivity in the metallurgical industries. Such powders enable

manufacture of components with high strength- to -weight ratios, improved

fracture toughness, unique magnetic properties, and high corrosion and

fatigue resistance. To assist U.S. industry in this area, the NIST Office of

Non- Destructive Evaluation (NDE) has formed an industry -government consortium

to develop and demonstrate process models, measurement methods, and expert

systems needed to monitor, control, and optimize the productivity of this

process in a Supersonic Inert-Gas Metal Atomizer (SIGMA)

To attain this objective, a NIST team has been formed which brings

together four different capabilities, metallurgy, fluid flow, optical

diagnostics, and automation. In this program, the Fluid Flow Group has

conducted a range of experiments on the fluid phenomena and interactions that

occur through the operation of a generic atomization die , a device which

produces liquid metal breakup and powderization through flow field

interactions. The flow research strategy is to begin with the gas -only flow

field and determine the characteristics of this flow as operating conditions

(i.e., temperature and pressure) are made closer to those used in the actual

process. These tests have involved a range of measurement methods which have

focused on the velocity and pressure distributions in the gas -liquid

interaction zones . These measurements have supplemented and enhanced our

previous shadowgraph and schlieren results to give both qualitative and

quantitative descriptions of the gas only and the gas -liquid flow fields.

High speed holography of the gas -liquid flows has been performed. For the

first time the rapid liquid and droplet motion has been recorded and shows

the details of the liquid break-up patterns.

*NIST Institute for Materials Science and Engineering

MULTIPHASE REACTING FLOWS GROUP

Mass Transport in Porous Media

B. Robertson, A.C. Van Orden, A.K. Gaigalas

An experimental study of flow through porous media has been undertaken

in order to predict dispersion of hazardous wastes from ruptured underground

107
tanks. The flow of water in porous materials has been visualized using

magnetic resonance imaging (MRI) . Water flow in an initially dry bed can be

detected directly since the protons in water give a large signal. For

observing flow in a wet bed, a dilute solution of manganese ions in water can

be used to displace the pure water. The manganese ions quench the MRI signal

so the solution can be distinguished from pure water. In order for this

technique to be useful for quantitative measurements, it is necessary to have

a calibration of the amount of signal quenching caused by different amounts

of manganese in solution. This calibration was performed in preparation for

a study of flow in a saturated tuff, a volcanic deposit. A sample of tuff

was obtained from D. Evans of the University of Arizona. Calibration

procedures for determining the water content in the rock were developed.

Additional measurements of ion transport in porous media will be made by

measuring the AC electrochemical impedance, as a function of frequency, of a

porous medium saturated with an aqueous salt solution. The impedance at low

frequencies depends on the mass transport of ions, which is governed by

adsorption of the ions onto the surface of the pores and by diffusion of the

ions both in the liquid and on the surface. The low-frequency measurements

give much more information about mass transport than the usual measurement of

the high-frequency electrical conductivity of the saturated porous medium.

These measurements will be related to the results of the MRI measurements on

porous media.

Measurement of Solids Fraction in Two-Phase Flows

W.G. Cleveland and A.K. Gaigalas

A technique has been developed to measure the fraction of solids

suspended in a flowing water-based slurry. It is assumed that the slurry is

flowing in a conducting pipe which acts as a waveguide for radio waves. By

measuring the speed of radio waves propagating in the flowing slurry and

comparing it with the value for pure water, it is possible to infer the

amount of solid material carried by the water stream. Tests of the technique

in the laboratory have demonstrated a high degree of accuracy. Attempts to

adapt the instrument to the mill environment are in progress. Nonintrusive

antennas have been designed and installed in the prototype sensor, and their

performance is excellent. The one remaining problem is air entrainment in

the process stream.

The sensor's operational characteristics are being investigated in a

paper pulp loop simulating industrial process conditions. As expected, the

major contribution to measurement bias is the presence of air in the paper

slurry. Careful preparation of the pulp slurry has alleviated this problem

somewhat. Otherwise, small discrepancies between the expected and measured

dielectric constant are most likely due to the nature of the parameter

fitting algorithm. A small instability in the convergence of the algorithm

is under investigation.

108
Detection of Bubbles with Ultrasound

C. Gingrich, W. Cleveland, A.K. Gaigalas

Work with the radio frequency (RF) solids fraction sensor has

demonstrated that many slurries contain air bubbles which bias the measured

value of the solids fraction. By combining the RF meter with a bubble

detection scheme, it will be possible to extend the measurement to three

phase systems.

A bubble detection scheme was selected which provides a unique output in

the presence of bubbles . The scheme is based on the resonant radial

oscillations which bubbles undergo in the presence of a driving pressure

oscillation such as that caused by a sound wave. The solid particles may

scatter the sound wave, but they will not exhibit a resonant response. Thus

by detecting the resonant oscillations, it will be possible to detect the

presence of bubbles. The detection of the radial oscillations will be done

by scattering an ultrasound beam (0.5 MHz) from the bubbles. The

oscillations will be driven by a low frequency (20 kHz) sound wave. An

apparatus has been developed to verify the proposed bubble detection

technique, and modeling of the detector response has been initiated.

Electrophoretic Light Scattering (ELS)

S. Woo, A.K. Gaigalas, J.B. Hubbard*

The object of this study is to develop a technique to monitor protein

transport processes. It is well established that gel electrophoresis can be

used to identify a variety of proteins. The technique is based on the

differences in protein response to an electric field. ELS also uses the

variability of surface charge on the protein to detect differences in

electrophoretic velocity. The major difference is that ELS occurs in situ

and is orders of magnitude faster then the gel method.

During last year, the major effort involved measurement and

interpretation of the response of latex spheres to AC electric field

perturbations . Measurements were taken over a frequency range from 10 Hz to

1000 Hz. A homodyne detection scheme was utilized; in this case the measured

response consisted of an exponential decay modulated by the motion induced by

the electric field. The overall decay constant provided a measure of the

diffusion constant while the magnitude of the modulation gave a value of the

electrophoretic mobility. It was found that the electrophoretic mobility of

latex particles varies with frequency. The variation is most likely due to

inertial effects. The measured diffusion coefficient did not depend on the

frequency of the applied electric field. At lower frequencies (f < 50 Hz)

,

the response of the latex particles was nonlinear as indicated by the

presence of large second harmonic components in the modulation of the

correlation function. The nonlinear behavior most likely arises from the

hydrodynamic interaction between the particles and the fluid. The presence

of nonlinearity complicates the connection of the zero frequency (DC)

109
electrophoretic mobility to that observed at higher frequencies. The study

of the frequency response is continuing; in addition, a heterodyne detection

scheme is being implemented.

*Thermophysics Division

Electrochemical Measurement of Diffusion Coefficients

B. Robertson, A.K. Gaigalas, B. Tribollet,* C. Deslouis*

A new electrohydrodynamic (EHD) method has been developed for

measurement of the Schmidt number in solutions, and the results have been

compared with those obtained using the DC method of Levich utilizing a

rotating disk electrode. With the EHD method, the speed of rotation of the

disk is modulated sinusoidally, and the resulting sinusoidal variation of the

limiting current is measured. The advantage of the EHD method is that it

does not require measuring the area of the electrode, the number of electrons

transferred in the redox reaction, or the concentration of the limiting

reactant, as does the DC method. The two methods agree within 1 percent when

the EHD measurement is done at a low disk velocity.

The method can be used to obtain a measurement of the diffusivity of a

protein that undergoes a redox reaction, as do many proteins. This

measurement will be compared with the ELS measurement of diffusivity. Also a

knowledge of the diffusion coefficient in the pure liquid is necessary for

studying mass transfer in a porous medium.

^University of Pierre and Marie Curie, Paris, France.

Electric Field Effects on Transport Through Membranes

R.D. As turn i an

The active transport of many ions and molecules is governed by specific

enzymes imbedded in the cell membrane. The control of these transport

enzymes is of great importance for optimizing and controlling bioreactors.

The electroconformational model formulated by R. Astumian and T. Tsong

suggests a mechanism by which enzymes can utilize energy from external

electric fields to transport molecules across membranes. Lactose permease, a

well studied protein, will serve as an excellent model system to

experimentally test the predictions of this model. These experiments will

also demonstrate the potential for utilizing electric fields to control

active membrane transport in practical systems.

Biodegradation of Metals

A.C. Van Orden, S. Woo

Nuclear waste containers are designed to last for approximately 1000

years. The design material for these containers, in two of the planned

110
repository locations, is A- 216 carbon steel. This project seeks to estimate

the enhancement of the corrosion rate of these containers by microorganisms.

Microorganisms may enhance or induce corrosion by altering the normal

electrochemical processes associated with the corrosion of the metal

interface

A variety of microorganisms contribute to the biodegradation of metal

interfaces . The work will be focused on two bacteria which are known to be

widely distributed and which have been implicated in the corrosion of metals.

The two types of bacteria which have been chosen are species of a sulfate

reducing bacteria and a species of an iron oxidizing bacteria. The

experimental facilities have been completed, the microorganisms have been

acquired, and the culturing activity has been initiated.

The experimental work is aimed at elucidation of the mechanisms for

biodegradation. The action of microorganisms will be monitored

electrochemically and optically by fluorescence imaging. The electrochemical

measurement gives the total metal dissolution rate while the fluorescence

measurements provide an indication of the quantity of metal which has been

taken up by the microorganism.

HIGH TEMPERATURE REACTING FLOWS GROUP

Destruction of Hazardous Waste in Fluidized Beds

A. Macek, N.D. Amin, S.R. Charagundla

Control of products of incomplete combustion, generated during

incineration of hazardous wastes, requires an understanding of rates and

mechanisms of thermal decomposition and oxidation of its principal

constituents (mainly chlorinated hydrocarbons) . The experiments to provide

such an understanding should be performed under well-controlled operating

conditions which simulate full-scale incineration systems. A literature

survey, made earlier under EPA sponsorship, showed that fluidized beds offer

a promising option for efficient incineration of a wide variety of wastes,

including chlorinated hydrocarbons

The first experimental step was a preliminary study of oxidation of two

simple model compounds, propane and methyl chloride. These experiments were

performed in a fluidized bed reactor which had been designed and used

previously for coal combustion studies. Recently, a new reactor was

constructed, allowing longer in-bed residence times, better temperature and

chemical composition control of fluidizing gases, and better mixing of model

compounds with the fluidizing gas. The reactor has been equipped with a set

of on-line gas monitors for determination of destruction efficiencies of

organic compounds. Oxidation of propane and methyl chloride was studied at

temperatures ranging from 250 to 650°C in beds consisting of particles having

different chemical compositions. Increasing catalytic effects were

demonstrated as one proceeds from silica to alumina to chromia.

Ill
Future plans include: (a) parallel plug- flow and fluidized bed

oxidization and pyrolysis studies of chlorinated hydrocarbons; (b) research

on retention of chlorine -containing reaction products in the fluidized bed by

means of solid sorbents; and (c) studies of fluidized bed destruction of

solid and liquid agents. The planned diagnostic techniques for model

compounds and incomplete combustion products include gas chromatography with

mass spectrometric detection and FTIR analysis.

Particle Formation in High Temperature Reacting Flows

M.R. Zachariah, H.G. Semerjian

Investigations are under way to explore the feasibility of using flames

as the reacting environment for the formation of refractory particles. The

goal of the project is to investigate the underlying physico-chemical

processes leading to particle formation and growth, and suggest ways in which

one might control the underlying chemistry and physics through changes in

process parameters, to affect the final product purity, particle size, and

polydispersity . Additionally, several nonintrusive laser diagnostic

techniques will be used to evaluate and clarify their limitations and

advantages for different applications.

Current efforts have focused on the formation of silicon dioxide

particles in a hydrogen/oxygen counter- flow diffusion flame with addition of

silane to the fuel. This geometry has been shown to provide a flat, highly

uniform environment suitable for optical probing. Temperatures have been

measured by both fine-wire thermocouples and OH absorption techniques. Insitu particle size data were obtained using dynamic light scattering and/or

scattering assymmetry measurements. These two techniques give comparable

results. Particle number densities were determined using static light

scattering techniques in conjunction with Mie scattering theory calculations.

Previous results showed that the silane loading, the equivalence ratio,

and the temperature affect particle size, shape, and number densities. In

addition, the results suggest that particle formation and the eventual growth

mechanism are highly coupled to the precursor gas kinetics. Most recently,

other silicon containing compounds have been used as the starting material in

order to investigate precursor effets. In addition, two numerical models

have been developed to simulate the various aspects of particle formation and

growth processes. The simulations account for consumption of the reactant,

nucleation, and growth, for a given time- temperature history. Future plans

include extension of particle formation studies to other refractory oxides

and other reactor geometries, e.g., flat-flame burners.

Particulate and Droplet Diagnostics in Spray Flames

C. Presser, A.K. Gupta,* H.G. Semerjian

Dynamics of spray flames are being studied to investigate droplet

vaporization, pyrolysis, combustion, and particulate formation processes, and

to delineate the effect of chemical and physical properties of fuels on these

processes. The results of this study will provide an experimental data base

112
for the development and validation of spray combustion models being developed

by JPL, Sandia, and Los Alamos National Laboratories. The experiments are

being carried out in a spray combustion facility, with a movable -vane swirl

burner, which simulates operating conditions in practical combustion systems.

A combination of nonintrusive probing techniques is being used to obtain

comprehensive data on the spray combustion characteristics, including soot

particle and droplet size, number density and volume fraction, gas

composition, and velocity and temperature fields.

Current research is focused on two areas, namely the effect of fuel

properties and atomizer geometry on spray and flame characteristics. To

address the first question, experiments are planned with heptane and No. 6

residual oil as fuels, in addition to the earlier experiments with kerosene.

Heptane is a single -component fuel which will provide extensive data for

modeling efforts. The experiments with No. 6 fuel oil will provide data

which are of greatest interest to industry, because of the difficulties

encountered in atomization, flame stability, and pollutant emission

characteristics. Current flow visualization experiments carried out with

heptane have already shown significant differences in flame stability and

emission characteristics.

Laser ensemble scattering and Doppler velocimetry measurements are being

carried out with an air-assist atomizer typical of those used in industry,

especially for heavy fuels. Unlike the pressure atomizer studied previously,

this injector can provide different atomization characteristics by varying

the atomizer air flow rate for the same fuel flowrate; it thus allows one to

study the effects of atomization on overall spray and flame structure. This

research nozzle is also being used by investigators at the University of

California- Irvine and Carnegie-Mellon University; this will allow for direct

comparison with our results and establishment of a broad experimental data

base. In addition to the ensemble light scattering measurements, data will

be obtained with other measurement techniques: (a) phase/Doppler

interferometry; (b) light intensity deconvolution technique (single particle

counters); and (c) laser diffraction technique (ensemble line-of -sight) . In

an effort to reduce data acquisition times and to provide single particle

counting capability, a new detection system has been assembled in which two

detectors are used to measure both scattering coefficients (Qhh an<^ Qw)

simultaneously, thus determining the instantaneous values of the polarization

ratio and particle size.

^University of Maryland

Optical Diagnostics for Metal Powder Atomization Systems

C. Presser, S. Ridder,* F. Biancaniello*

Particle size measurement techniques have been evaluated to determine

their applicability to jet break-up and droplet formation processes in a

metal powder atomization chamber. The techniques of interest to measure

particle size, number density, and velocity include: (a) phase/Doppler

interferometry and (b) scattering intensity deconvolution techniques. These

systems will be used for diagnostics in the atomization chamber to provide

113
data for development of process models, for input into expert systems, and

for process optimization. High-speed cinematography of the upstream portion

of the metal spray has indicated the time -dependent nature of the metal

atomization process. In addition, a laser diffraction technique has been

chosen to provide particle size distribution measurements along a line of

sight near the exit of the chamber. This particle size distribution,

averaged along a cross section of the process stream, can then be used for

process feedback and control. Currently, experiments are underway to

demonstrate the feasibility of particle size measurements through the exit

section of the atomizer chamber which has been modified to incorporate two

windows 180° apart. Interpretation of data obtained through an optically

thick stream is the focus of the present work.

*NIST Institute for Materials Science and Engineering

Numerical Modeling of High-Temperature Reacting Flows

R.W. Davis, E.F. Moore

High- temperature reacting flows are, in general, typified by strong

coupling between fluid mechanical and chemical kinetic processes. In most

practical systems, such reacting flows are characterized by large

fluctuations in species concentration and temperature which occur over small

spatial intervals. In order to gain an improved understanding of such

complex reacting flows, a joint numerical -experimental program is being

carried out.

Because of its simple flow configuration, this program focuses on the

axisymmetric jet diffusion flame. A numerical model of this flame has been

developed as part of a joint computational -experimental research effort to

study the structure of unsteady diffusion flames. This work is being carried

out in cooperation with the Wright Patterson AFB. The model includes

buoyancy effects and is currently being used to study the dynamic

interactions between the flame surface and the surrounding vortex structures.

These interactions are poorly understood at present and they strongly

influence the basic physics involved in these flames. The types of

interactions predicted by the computations compare well with those observed

experimentally. The model provides a complete description of the flow,

species, and thermophysical properties fields and permits rapid assessment of

the effects of parameter variations. Continued close cooperation between the

numerical and experimental efforts is planned to provide guidance to the

experimentalists and to ensure that the model remains firmly grounded in

reality.

High-Speed Laser Tomography

R.G. Joklik, D.R.F. Burgess, R.E. Snyder, H.G. Semerj ian

The technique of high speed laser tomography is under development to

allow rapid measurements of temperature and chemical species concentration

distributions throughout a two-dimensional "slice" within time varying

114
chemically reacting flow fields. Work has progressed from time averaged

measurements of steady phenomena , such as laminar diffusion flames and

gaseous jets, to real time measurements in sodium- seeded flames. Using the

experience gained, the temperature and OH concentration field were measured

in a premixed methane flame in a 5 ms period. This was achieved by sweeping

an ultraviolet laser beam through the field every millisecond while tuning

the laser frequency over an OH absorption line. The experiment used an

axially symmetric flame, requiring only a single measurement angle. The

temperature was determined from the measured absorption line width.

Current work has focused on two main areas. To improve the sensitivity

of the temperature measurements , particularly in zones of low OH

concentrations, a two-line ratio technique is being implemented. The

frequency scanning range and speed of the dye laser used for the OH

measurements has been extended to allow temperature measurements of this type

at a rate greater than 1 kHz. Also, a new multiangular tomographic system

has been developed for rapid measurements in assymmetric fields at repetition

rates up to 10 kHz. This six-angle system has been used to measure the soot

concentration field in rapidly fluctuating ethene-air jet diffusion flames

with a time resolution of better than 1 ms. Future experiments will measure

mixture fraction, temperature, and OH concentration in these flames.

Comparison of these data with concurrent modeling results is aimed at

understanding the dynamics of flame-flow field interactions, which control

the processes of vortex formation, shedding, and break-up. Details of eddy

formation in the jet have also been observed using a laser sheet imaging

technique in a plane intersecting the centerline of the jet. In this

technique, titanium chloride is seeded into the fuel jet, and titanium oxide

particles are formed in a narrow zone by reaction with combustion generated

water. Scattered laser light from the particles is then used for flow

visualization.

Flame Temperature Measurements bv Laser Excited Fluorescence

J.J. Horvath, R.G. Joklik, H.G. Semerjian

A new nonintrusive temperature measurement technique, thermally assisted

laser induced fluorescence (TALIF) , is being developed for measurements in

high- temperature chemically reacting flows. In this method, an upper

electronic state is populated from the ground state by means of laser

excitation. The population in this excited level is collisionally

redistributed, then radiatively decays, and the resultant fluorescence is

detected as a function of energy level. The temperature can be obtained by

plotting the observed fluorescence intensities as a function of the upper

energy level. This distribution could also be used to ascertain the presence

of a Boltzmann distribution throughout the higher energy levels. One can

also measure two wavelengths simultaneously and obtain a temperature from a

single laser pulse. The fluorescence observed is from the anti -Stokes line

of the excitation pulse, hence this method is applicable to high luminosity

flames and conditions of high background Stokes fluorescence.

Initial experiments have used gallium as the seeding species in premixed

flames. A tunable dye laser, pumped by a nitrogen laser, was used to excite

115
the ^Pl/2‘5Sx/2 transition of Ga at 403.3 ran, and the resultant fluorescence

from upper levels was observed. Premixed CH4/Ar/02 , CH4/Air, C2H4/Ar/02, and

C2H4/Air flames were studied to determine the useful temperature range of

this technique. Temperatures of these flames could be varied from approximately 1950 to 2500 K depending on flow conditions. Measured temperatures

were about 100-150 K below the adiabatic flame temperature. Fluorescence

signals were also obtained in an ethylene diffusion flame, but an unexpected

broad band fluorescence was observed which yielded abnormally high

temperatures. To correct for this broad band fluorescence interference,

computerized data reduction schemes have been developed.

Recent work has used an Nd-YAG pumped dye laser for greater spectral

coverage of the useful wavelengths. This work has focussed on determining

the temperature range of useful thermometric species. Time-resolved

fluorescence measurements indicated that upward collisional transfer rates

are faster than the downward rates, as predicted by theory. Current work

involves using a wavelength modulation technique to perform sodium line

reversal temperature measurements on various flames to compare with the

fluorescence values. Future studies will include substitution of nitrogen in

the flame by argon to evaluate quenching effects and the use of naturally

occurring molecular species (OH, CH, C 2 ) for fluorescence studies. The

ultimate goal is the development of single laser pulse temperature

measurement techniques for use in industrial and scientific applications over

a wide range of temperatures

Fluorescence Spectroscopy for Control of Paper Pulping Processes

J.J. Horvath, H.G. Semerj ian

There is an increasing need for the development of measurement science

and technology for on-line measurement of process variables in the pulp and

paper industry. Current process techniques for measurement of

delignification rates in the pulping process are based on sampling and offline analysis systems. The resultant delay prevents the on-line control of

the digester and pulping processes, and results in less than optimum

operating conditions. The ideal process monitoring technique would be both

an in- situ and real-time measurement system, so that important variables of

the digestion process can be monitored and corrections applied before a cook

is completed. The goal of this project is to develop in-situ techniques,

based on fluorescence spectroscopy, for monitoring pulping processes.

In these studies, laser excited fluorescence of black liquor was

investigated as a possible monitoring technique for pulping processes. A

pulsed dye laser was used to examine the fluorescence spectrum of black

liquor solutions. Various excitation wavelengths between 280 and 403 nm were

used. Black liquor fluorescence spectra were found to vary with both

excitation wavelength and black liquor concentration, providing good

detection limits and linear response over a large dynamic range. Recently,

measurements have also been made on optically dense pulping liquors, obtained

from a paper mill, using a backscatter configuration without any sample

dilution. The fluorescence spectra obtained from these samples were found to

vary with processing time, indicating a good possibility of using

116
fluorescence for process control and monitoring. In order to quantify these

measurements, additional experiments were performed with well characterized

pulp liquor samples of known composition. The results with these samples

showed the fluorescence intensity to vary linearly with lignin concentration

up to 1 g/1 dissolved lignin. The fluorescence spectrum also indicated a

chemical change occurring near the end of a cook, something speculated upon

in the literature. Fluorescence from paper pulp streams and paper fibers has

also been investigated; results indicate the fluorescence signal to be

related to the lignin content.

Optical Diagnostics for Investigation of CVD Processes

D.R.F. Burgess, M.R. Zachariah

The development of microscopic descriptions of chemical vapor deposition

(CVD) processes has been hampered by the difficult task of detecting small

concentrations of gas-phase reactive species. Most investigations have

focused on macroscopic observables, such as pressure and temperature effects.

By providing selectivity in the creation and detection of reactive species in

CVD, one can identify the reactions and species which are critical to

deposition processes and, consequently, be able to control the uniformity and

quality of epitaxial growths. Our approach to this problem is to employ

optical techniques, which are highly species specific, to create, detect, and

measure the reactivity of important gas phase intermediates in CVD processes.

Currently the focus is on the gas phase chemistry of silane and ammonia

fragments relevant to silicon nitride deposition.

The experiments are carried out using pre -mixed gases in a windowed cell

with a reactive flow of a mixture of silane and ammonia in argon surrounded

by an argon shroud flow. The flow rate, concentrations, and total pressure

are controlled using electronic flow controllers and a vacuum pump. UV light

from an excimer laser is used to photolyze silane and ammonia, creating

reactive fragments, and initiating gas phase chemistry. The photolysis

process is monitored via emission from excited photofragments. Reactivities

of fragments with silane and ammonia are determined by measuring their time

dependent concentrations using laser- induced fluorescence (LIF) . Silane and

ammonia photolysis processes have been characterized using emission

spectroscopy under a range of conditions, from concentrations where fragments

are rapidly quenched to regions where particles are formed in the gas phase.

Future studies will include investigation of the kinetics of the chemical

processes important in CVD systems using LIF techniques.

Optical Sensing in Bioreactors

J.J. Horvath, A. Enriquez,* H.G. Semerjian, A.E. Humphrey*

Implementation of new biochemical processes for production of new drugs

and chemicals, conversion of biomass, etc., requires new measurement

capabilities. Bioprocesses require very closely controlled environments,

normally realizable only in batch processes. This is mainly due to the

complex kinetics of most bioreactions, separate periods of growth and product

117
formation, biocatalyst degeneration, contaminant risks, and mechanical

difficulties of handling a rheologically complex material. Therefore,

development of new on-line measurement techniques is critical for future

implementation of bioprocesses. Furthermore, nonintrusive measurement

methods are desirable to avoid difficulties associated with sampling,

contamination, long response time, etc. Optical techniques provide the best

potential for making nonintrusive, rapid, and selective measurements. Use of

fiber optics can also enable the development of probes which are

sterilizable , can provide measurements with good spatial resolution, and can

be multiplexed to provide multipoint monitoring capability. Laser- induced

fluorescence (LIF) , Raman scattering, and infrared absorption techniques will

be utilized for measurement of key process variables such as cell mass

activity, cell concentration, and concentration of substrates and products.

Experiments have been carried out on fluorescence characteristics of

aromatic amino acids and a series of dipeptides and polypeptides to determine

the effects of amino acid sequence and various chemical functional groups on

the observed fluorescence spectra. Preliminary results with dipeptides of

phenylalanine (Phe) and glycine (Gly) have demonstrated significant

sensitivity to sequencing. Further studies are underway with dipeptides of

tyrosine and tryptophan. The fluorescence spectra of commercially produced

biomolecules, such as antibiotics and artificial sweeteners, have also been

investigated. Spectra of the components of a typical fermentation, i.e.,

yeast, nutrient, and the product enzyme, have been examined and characterized

as a function of excitation wavelength. Present work involves use of these

spectra for on-line monitoring of fermentation using a flow-through cuvette.

The characteristic fluorescence spectra from the yeast and nutrients are used

to monitor the state of the fermentation, nutrient uptake, and the growth

rate of yeast. Good correlation has been obtained between the fluorescence

and dry cell weight measurements. A new microbial fermentation system to

produce the antibiotic bacitracin is currently being set up; it will be

monitored using fluorescence techniques.

Work is also under way with the University of Maryland to develop

deconvolution techniques for determining the concentration of single

components in complex multicomponent mixtures. Several other approaches are

being explored to improve the selectivity of fluorescence measurements.

Preliminary measurements performed using two-photon fluorescence and

fluorescence lifetimes indicate good promise for improving selectivity. The

recently acquired scanning spectrofluorometer has been used to obtain

excitation/emission spectra which can be displayed as 3-D plots or contour

plots. Data processing techniques are being developed for using these data

to determine single components in multicomponent mixtures. In the future,

other techniques such as synchronous scanning fluorescence spectroscopy, and

Raman and resonance Raman scattering will be used to provide improved species

selectivity. Fluorescence techniques are also expected to provide a powerful

tool for cell activity and intracellular kinetics measurements.

*Lehigh University

118
PROCESS SENSING GROUP

Humidity Calibration

S. Hasegawa, P. Huang, G. Scace

To date, humidity calibrations have been provided using the two -pressure

humidity generator which operates over the dew-point range of -60°C to 30° C.

In response to an increasing demand, especially from the microelectronics

industry, for calibration standards below 1 ppm, a new low- frost point

generator facility is under development. This generator will be capable of

producing gas streams having moisture concentrations of approximately 15 ppb

to above 2 ppm (dew points from -100°C to above -60°C)

The system is

currently operational and efforts on the low frost point generator have

concentrated on (1) continued development of proper operating procedures,

e.g., methods to obtain reliable ice coating of the saturator section, and

(2) the use of a primary electrolytic moisture concentration measurement

method for validation of proper operation.

Thin Film Thermocouples for Heat Engines

K.G. Kreider

A cooperative effort with the Office of Transportation Systems of DoE,

NASA-Lewis, a commercial firm, and Purdue University has been used to

demonstrate the feasibility of measuring the interior temperatures of

ceramic-lined diesel engines. The NIST role was to sputter-deposit the thin

film platinum and gold based thermocouples on the sensor plugs used to

acquire heat transfer and real time thermal histories of diesel engines. The

adhesion technology developed previously at NIST was used to obtain suitable

durability and performance on the partially stabilized, plasma sprayed

zirconia cylinder liners. Engine tests performed at Purdue University on a

diesel engine verified the theoretical predictions made in the DoE programs

and corrected earlier misleading results obtained with inferior probes. Thus

the advantages of ceramic insulation in these diesel engines were verified.

A patent application has been submitted to the Department of Commerce

and the DoE on the use of sputtered ultrathin bonding layers of reactive

metals between the ceramic and the noble metal sputtered thin film

thermocouples. Continuing effort in this area is planned to assist the DoE

engine test program and to develop high temperature (up to 1750° C) sputtered

thin film thermocouples

Solid State Gas Sensors

S. Semancik, T.B. Fryberger

Experimental research has been done on semiconducting oxide materials to

examine the mechanistic processes at work in conductance- type gas sensors.

The ultimate goal of this work is to improve the sensing properties of such

solid state materials by understanding how adsorbed gases modify their

119
electrical properties. Tin oxide (Sn02) has been the focus of these studies

since it is capable of responding to both oxidizing and reducing gases, and

is already used as the base material in some gas sensors

Results obtained thus far, in model studies on Sn02 crystals, have

demonstrated the key role of oxygen vacancies and structural defects in

determining the conductivity level for this n-type semiconductor. We have

also shown that vacancy concentration changes can occur primarily in the

outermost portion (~5 nm) of Sn02(110) crystallites; thereby dominating the

electrical behavior of the entire crystallite. These findings are very

important since they indicate that future sensors may take advantage of the

surface sensitive response in materials like tin oxide to minimize

undesirable sensor characteristics (e.g., slow response, drift, hysteresis)

by suppressing bulk diffusional processes.

We are also developing an increased understanding of the action of metal

additives for producing enhanced and more selective sensor response.

Experimental work on the Pd/Sn02 system has shown that the chemical

interaction between palladium and the base oxide is relatively weak, and that

the Pd tends to cluster when it is surface-dispersed on various types of Sn02

specimens. These island-like overlayers produce a composite metal/oxide

system with semiconducting characteristics that are desirable for gas sensing

applications. When tested as a hydrogen sensor, our Pd/Sn02 prototype

specimen exhibited a 16-fold enhancement over pure Sn02- These results, if

compared to those for bulk- loaded Pd in Sn02 , suggest that higher detection

efficiencies can be attained using surface-dispersed additives.

Continued work in this project will involve investigating response

modifications produced by other selectivity enhancing metals including

silver, platinum, and tin. We will also study the temperature and pressure

dependence of gas -induced conductivity changes in metal/Sn02 systems, as well

as sensing interference effects that develop in gas mixtures.

Ultrathin Chemical Sensors

S. Semancik, M.J. Tarlov, T.B. Fryberger

This new project will expand upon findings from our earlier work on gas

sensing materials to develop the scientific base for an advanced generation

of detection elements for use in gaseous and liquid environments. The

fundamental idea is that sensing processes can be limited to the surface

regions of certain materials, thereby eliminating measurement problems that

can originate in the bulk, e.g., drift and hysteresis.

Oxide films, having thicknesses of 1 to 10 nm, will be deposited and

characterized (interactively) in order to optimize their sensing

capabilities. A primary objective of this project will be to determine the

ultimate effectiveness for (ultra) thin oxide films when used in multisensor

arrays. Efforts will concentrate on ultrathin forms of two proven sensing

oxides: tin oxide (Sn02) and iridium oxide (Ir02)

Bulk and thick film

forms of these oxides have already been used successfully in gas sensing and

120
pH sensing applications, respectively. We will consider pure Sn02 and Ir02

as well as purposely modified forms produced by the introduction of various

"dopants" (including catalytic metals).

In the initial stages of work, which took place during FY 88, plans were

developed for a special ultrahigh vacuum facility where oxide films can be

deposited, characterized, and tested. Construction of this equipment will

take place in FY 89. Two aspects which will be investigated first are the

type of oxidation procedure to be used for forming the films and the nature

of the epitaxy that occurs on various substrates. Preliminary results for

Sn02 have indicated difficulties with thermal fabrication procedures

therefore, we expect to move next to reactive deposition processing. While

early parts of the research will focus on fabrication techniques and

micros tructural characterization, the later efforts will be concerned with

response behavior and material stability in operation. New electrical

measurement capabilities will also need to be developed in the course of the

proj ect

The study of these novel sensing elements is expected to have a major

impact on the development of improved thin film forms of solid state

materials for gaseous and aqueous composition sensing. Successes in this

research program would also point the way for using planar technology to

manufacture multicomponent, selective sensor arrays.

Superconducting Sensors

K.G. Kreider

Thin film YBa2Cu0y_ x superconductors were produced by magnetron

sputtering from a single target followed by crystallization and oxidation in

oxygen. These films were produced on monolithic substrates including MgO

single crystals and yttria-stabilized ZrC>2 and were produced on silicon

wafers and alumina substrates using magnetron sputtered Zr02 as a chemical

diffusion barrier during the 900° C heat treatment. Two areas of interest to

CCT are the development of sensors for the chemical industries, based on

superconducting quantized interference devices (SQUIDS), for detection of

charge exchange reactions, and the chemical reactivity of the films to H2 O

and CO2 in air. Early studies have focussed on the relationship between film

stoichiometry and fabrication parameters. It was found that controlling the

oxygen partial pressure during sputtering was extremely critical to obtain

1:2:3 stoichiometry and sharp high temperature superconducting transitions.

Ir0 2 Ionic Sensors

M.J. Tarlov, K.G. Kreider, P.H. Huang, S. Semancik

Reactively sputtered iridium oxide (Ir02) is being investigated as a pH

sensing material. The pH sensitive iridium oxide films offer several

advantages over conventional glass pH electrodes: (1) iridium oxide films

are stable in aqueous solutions of extreme pH and temperature whereas glass

electrodes tend to dissolve, (2) iridium oxide thin films can be readily

121
deposited on probes that are smaller and more mechanically rigid than glass

electrodes, and (3) iridium oxide films have a much lower impedance than

glass membranes. During the past year, we have been evaluating the pH

sensing performance of DC magnetron reactively sputtered iridium oxide films

relative to that of the glass electrode. In addition, ultrahigh vacuum

electron and ion spectroscopies have been used to examine the composition and

structure of model iridium oxide sensor surfaces. It is expected that this

will provide an improved microscopic understanding of the pH sensing

mechanism and the cause of electrode instability.

A number of criteria have been used to evaluate the performance of

iridium oxide as a pH probe. Iridium oxide films deposited on a variety of

substrates have shown near-Nernstian behavior in the pH range of 2 to 12.

Also, the sensitivity of the films to ionic interferences has been relatively

low in comparison to the glass electrode. Preliminary work has indicated

that dissolved redox and gas species may represent the most serious

interferences for iridium oxide electrodes. This is not surprising in light

of iridium oxide's electronic conductivity. Electrode potential drift

(instability) has been another problem, and slow hydroxylation reactions at

the electrode/solution interface are thought to be responsible. A systematic

study of the relationship between Ir02 film crystallinity (film structure may

be controlled from amorphous to polycrystalline) and electrode response is

underway.

To understand the fundamental reactions occurring at the IrC^/solution

interface that determine electrode behavior, model IrC>2 sensor surfaces were

examined with x-ray and ultraviolet photoemission, and ion scattering

spectroscopy. Surprisingly, little or no reaction was observed between large

doses of gas -phase water and clean IrC>2 surfaces prepared by ion bombardment

and annealing in oxygen. However, it was found that adsorption could be

activated by rf plasma excitation. The results obtained from these model

surfaces will greatly aid in the interpretation of data obtained from "real"

Ir02 sensor surfaces.

The combination of electrochemical and surface analytical techniques are

the basis for a research strategy directed toward the development of improved

ionic sensing materials. An understanding of the fundamental principles of

electrode operation is a necessary step in the logical design of more

selective and specialized ionic sensors.

5. PUBLICATIONS

Avedisian, C.T., Presser, C. , Gupta, A.K. and Semerjian, H.G. , Structure of a

burning n-heptane spray generated from a pressure -jet atomizer, Proc

1988 Fall Technical Meeting, Eastern Section of the Combustion Institute,

pp. 107. 1- . 4, Clearwater, FL (Dec. 1988).

Biancaniello , F. , Conway, S., Espina, P., Mattingly, G. and Ridder, S.,

Particle size measurement of inert gas atomized powder, Proc.

Metallurgical Soc. Fall Meeting, Chicago, IL (Sept. 1988) (submitted).

122
Biancaniello, F. , Espina, P. , Mattingly, G. and Ridder, S., A flow

visualization study of supersonic inert gas metal atomization, Proc

Metallurgical Soc. Fall Meeting, Chicago, IL (Sept. 1988) (submitted).

Biancaniello, F. , Presjer, C. and Ridder, S.D., Real-time particle size

analysis during inert gas atomization, Proc. Metallurgical Soc., Fall

Meeting, Chicago, IL (Sept. 1988) (submitted).

Burgess, D. , Cavanagh, R.R. and King, D.S., Laser- induced desorption: thermal

and nonthermal pathways, J. Chem. Phys . , Vol . 88 , p. 6556 (1988).

Burgess, D. , Cavanagh, R.R. and King, D.S., NO/NH3 coadsorption of Pt(lll)

kinetic and dynamical effects in rotational accommodation, Surface

Science (submitted)

Burgess, D. , King, D.S. and Cavanagh, R.R.

,

Kinetics and dynamics of the

nitric oxide/ammonia interaction on Pt(lll)

,

J. Vac. Sci. Technol., Vol.

A5 , p. 2959 (1987).

Charagundla, S.R., Macek, A., Semerjian, H.G. and Whetstone, J.R., A

spectroscopic measurement technique for black-liquor recovery boilers,

AIChE Annual Meeting, Washington, D.C. (Nov. 1988) (submitted).

Clay, D.T., Lien, S.J., Grace, T.M., Macek, A., Semerjian, H.G., Amin, N. and

Charagundla, S.R., Fundamental studies of black liquor combustion, Report

No. 2, DoE Report DOE/CE/40637 -T2 (DE88005756) (1987).

Cleveland, W.G., Mease, N.E. and Gaigalas , A.K.

,

Determination of solids

fraction in slurries by RF diagnostic techniques, Symp . on Process

Sensing and Diagnostics, AIChE Annual Meeting, Washington, DC (Nov. 1988)

(submitted)

Cox, D.F., Fryberger, T.B. and Semancik, S., Oxygen vacancies and defect

electronic states on the Sn02 (110) - lxl surface, Phys. Rev., Vol. B38,

p. 2072 (1988).

Cox, D.F., Fryberger, T.B. and Semancik, S,, Summary abstract:

oxygen -vacancy -derived defect electronic states on the Sn02 ( 110 ) surface,

J. Vac. Sci. & Tech, Vol. A6 , No. 3, p. 828 (1988).

Erickson, J.W., Fryberger, T.B. and Semancik, S., Metal/semiconductor

interfaces on Sn02 ( 110 ), J. Vac. Sci. & Tech., Vol. A6 , No. 3, p. 1593

(1988) .

Fryberger, T.B.

,

Erickson, J.W. and Semancik, S., Chemical and electronic

properties of Pd/Sn02 ( 110 ) model gas sensors, Surface and Interface

Analysis (in press)

Gaigalas, A.K.

,

Robertson, B., Van Orden, A., Mareci, T.H. and Lewis, L.A.

,

Application of magnetic resonance imaging to visualization of flow in

porous media, Nuclear Tech, (in press).

123
Gosh, A.K. and Ulbrecht, J.J., Bubble formation from a sparger in a stagnant

polymer solution, AIChE Annual Meeting, New York, NY (Nov. 1987)

(submitted)

Gosh, A.K. and Ulbrecht, J.J., Bubble formation from a sparger in moving

polymer solutions, AIChE Annual Meeting, New York, NY (Nov. 1987)

(submitted)

Horvath, J.J., Semerjian, H.G.

,

Biasca, K.L. and Attala, R. , Laser induced

fluorescence for measurement of lignin concentrations in pulp liquor,

Int. Symp. on Optical Engineering and Industrial Sensing, SPIE, Vol. 961,

(June 1988) Dearborn, MI (in press).

Hsu, J.C.L., Clay, D.T. and Presser, C. , In-situ fume particle size and number

density measurement from synthetic smelt, IPC Technical Paper Series No.

100, (Aug. 1988), The Institute of Paper Chemistry, Appleton, WI

Hsu, J.C.L., Presser, C. and Clay, D.T.

,

In-situ fume particle size and number

density measurements from a synthetic smelt, Pulp and Paper Science

(submitted)

Huang, P.H., Surface acoustic wave microsensors using diffused substrates,

IEEE Trans, on Electron Devices, Vol. 35, No. 6, pp . 744-749 (1988).

Huang, P.H.

,

Polymeric humidity sensors for industrial process applications,

Proc. Sensors Expo 1988, Vol. 106B, pp. 1-16 (1988), Chicago, IL.

Huang, P.H.

,

Halogenated polymeric humidity sensors, Sensors and Actuators,

Vol. 13, pp. 329-337 (1988).

Huang, P.H. and Chiang, C.K.

,

Humidity effect on solid electrolyte: PEO-Nal

complexes, Bull. Am. Phys . Soc., Vol. 33, No. 3, p. 267 (1988).

Huang, P.H. and Kreider, K.G.

,

Electrochemical evaluation of solid state pH

sensors for nuclear waste containment, NIST IR 88-3790 (May 1988) and

NUREG/CR- 5166 (July 1988).

Kaufman, M.J., Biancaniello , F.S. and Kreider, K.G.

,

The annealing behavior of

sputter deposited Al-Mn and Al-Mn Si Films, J. Mat. Res. Soc. (Nov. 1988)

( in press) .

Kreider, K.G.

,

Thin film thermocouples, AIChE Annual Meeting, Washington, DC

(Nov. 1988) (submitted).

Kreider, K.G., Sputtered thin film Ba2YCu30n , Proc. of Workshop on High Temp.

Superconductors, Inst, for Tech, and Strategies Res. Coll., (Oct. 1987),

Washington, DC (submitted).

Kreider, K.G. and Yust, M. , Thin film thermocouples for heat engines, Proc.

Sensors Expo 1988, Vol. 106A, pp. 1-5 (Aug. 1988) Chicago, IL.

124
Kreider, K.G.

,

Shapiro, A. and Cline, J.P., Sputtered thin film Ba2YCn30n , Proc. of Am. Vac. Soc. Symp. on Processing and Characterization of Thin

Film High Temp. Superconductors, Atlanta, GA (Oct. 1988).

Macek, A. and Amin, N.D., Characterization of solids mixing in a laboratoryscale fluidized bed, DoE Report DoE/MC/21069-2376 (DE87006501) (1987).

Macek, A., Charagundla, S.R., Allen, J.D. and Semerjian, H.G., A study of

combustion spectra from an entrained- flow gasifier, DoE Report

(submitted)

Macek, A. and Amin, N.D.

,

Solids dispersion coefficients in high- temperature

fluidized beds, AIChE Symp. Series 262, Vol. 84, pp. 22-35 (1988).

Macek, A., Spears, N.O. and Chawla, R.C., Combustion of chlorinated

hydrocarbons in fluidized beds, AIChE Annual Meeting, Washington, D.C.,

(Nov. 1988) (submitted)

Mattingly, G.E., Gas flowrate metrology, Proc. NCSL Conf .

,

Washington, DC,

(Aug. 1988) (in press).

Mattingly, G.E., DOD/CCG-NIST round robin flow measurement testing for

hydrocarbon liquids, NIST Interim Report (Aug. 1988) (submitted).

Mattingly, G.E. and Mease, N.E., Gas flow measurement: practical aspects and

research results, Proc. of Institute of Gas Tech. (IGT) Symp. on Natural

Gas Energy Measurement, p. 26, (June 1988) Chicago, IL.

Mattingly, G.E. and Mease, N.E., Fluid flowrate facilities at NBS , Proc. 79th

Annual Conf. of the Int. District Heating and Cooling Assoc. (IDHCA)

,

Chautagua, NY (June 1988) (in press).

Mattingly, G.E. and Yeh, T.T., Flowmeter installation effects, Proc. NCSL

Conf., Washington, DC (Aug. 1988) (in press).

Mattingly, G.E. and Yeh, T.T.

,

NBS industry - Government consortium research

program on flowmeter installation effects: summary report July-Dee 1987,

NBS Interim Report (May 1988) (submitted)

Mattingly, G.E., et al .

,

Fluid mixing characteristics produced by piping

elbows, AIChE Annual Meeting, New York, NY (Nov. 1987) (submitted).

Presser, C.

,

Gupta, A.K.

,

Semerjian, H.G. and Santoro, R.J., Application of

laser diagnostic techniques for examination of fuel spray structure,

Chem. Eng. Commun. (submitted)

Presser, C. , Gupta, A.K.

,

Semerjian, H.G. and Santoro, R.J., Aerodynamic

effects on spray characteristics: pressure- jet atomizer, Comb, and Flame

(submitted)

125
Presser, C. , Gupta, A.K. and Semerjian, H.G. , Effect of atomization air on

droplet dynamics of spray flames, Proc . 1988 Fall Tech. Meeting, Eastern

Section of the Combust. Inst., pp . 105.1 -.4, Clearwater Beach, FL (Dec.

1988) (submitted)

Presser, C., Gupta, A.K. and Semerjian, H.G., Influence of size distribution

function on mean droplet size obtained by ensemble light scattering, 2nd

ASTM Symp. on Liquid Particle Size Measurement Techniques, ASTM Symp .

,

Atlanta, GA (Nov. 1988) (submitted).

Presser, C., Gupta, A.K. and Semerjian, H.G., Spray characteristics of a

research air-assist atomizer, 2nd Ann. Conf. on Liquid Atomization and

Spray Systems (ILASS Americas '88), Pittsburgh, PA (May 1988)

(submitted)

Presser, C., Gupta, A.K. and Semerjian, H.G. , Dynamics of pressure-jet and

air-assist nozzle sprays: aerodynamic effects, AIAA/ASME/SAE/ASEE 24th

Joint Propulsion Conference, Paper No. AIAA-88-3139 , Boston, MA (1988).

Presser, C., Gupta, A.K. and Semerjian, H.G., Aerodynamic effects on spray

characteristics: air-assist atomizer, ASME Winter Annual Meeting,

Chicago, IL (Dec. 1988) (submitted).

Robertson, B. , Tribollet, B. and Deslouis, C., Measurement of diffusion

coefficients by DC and EHD electrochemical methods, J. Electrochem. Soc.,

Vol . 135, pp. 2279-2284 (1988).

Robertson, J.L., Moss, S.C. and Kreider, K.G., Comparison of sputtered

amorphous and quasicrystalline films of Al 7 ?Mn ooSi 06 > Phys . Rev. Let.,

Vol. 60, No. 20 (May 1988).

Semancik, S., Surface analytical methods for studying sensing phenomena, Chap.

2 in book, Chemical Sensor Science (Springer-Verlag) (submitted)

Semancik, S., Materials properties of Sn02 surfaces and metal-Sn02 interfaces,

Chap. 3 in book, Chemical Sensor Science (Springer-Verlag) (submitted).

Semerjian, H.G., Zachariah, M.R. and Presser, C., Laser diagnostics for

investigation of particle formation processes, Proc. MRS Symposium on

Process Diagnostics, Vol. 117, pp . 137-150 (1988).

Solomon, P. , Best, P., Carangelo, R. , Markham, J., Chien, P. , Santoro, R.J.

and Semerjian, H.G. , FT-IR emission/transmission spectroscopy for in situ

combustion diagnostics, Proc. 21st Symp. (Int.) on Combust., pp . 1763-

1771 (1988).

Tsong, T.Y.

,

Lin, D.S., Chauvin, F. , Gaigalas, A. and Astumian, R.D.,

Resonance electroconformational coupling: an electric field induced

enzyme oscillation for cellular energy and signal transduction,

Bioelectrochemistry and Bioenergetics (submitted)

126
Van Orden, A.C., Dealloying in gold- silver- -an interface morphology problem,

Corrosion/88, Nat. Assoc. Corrosion Engr. (submitted).

Van Orden, A.C. and McNeil, M.B., Archaeological artifacts relevant to

long-term corrosion behavior, Proc. Materials Res. Soc. (submitted).

Whetstone, J.R., Charagundla, S.R., Macek, A. and Semerjian, H.G.,

Spectroscopic combustion temperature measurement: effects of optical

depth in black liquor recovery boilers, Int. Symp. on Optical Engineering

and Industrial Sensing, SPIE, Dearborn, MI (June 1988) (submitted).

Whetstone, J.R., Cleveland, W.G.

,

Bateman, B.R. and Sindt, C.F., Measurements

of coefficents of discharge for concentric, flange- tapped, square -edged

orifice meters in natural gas over the Reynolds number range 25 000 to

16 000 000, NIST Tech. Note (submitted).

Whetstone, J.R., Cleveland, W.G.

,

Baumgarten, G.P., Woo, S. and Croarkin,

M.C., Measurements of coefficients of discharge for concentric, flangetapped, square -edged orifice meters in water over the Reynolds number

range 1000 to 2 700 000, NIST Tech. Note (submitted).

Yust, M. and Kreider, K.G.

,

Transparent thin film thermocouples, Thin Solid

Films (submitted)

Zachariah, M.R.

,

Chin, D. , Semerjian, H.G. and Katz, J.L., Silica particle

formation in opposed jet diffusion flames, Combustion InstituteWestern States Section Meeting, Paper No. WSS/CI 88-46, Salt Lake

City, UT (Mar. 1988)

Zachariah, M.R.

,

Chin, D. , Semerjian, H.G. and Katz, J.L., Dynamic light

scattering and angular dissymmetry for the in- situ measurement of silicon

dioxide particle synthesis in flames, Applied Optics (in press).

Zachariah, M.R.

,

Chin, D. , Semerjian, H.G. and Katz, J.L., Silica particle

formation in a counter flow diffusion flame reactor, Combustion and Flame

(in press)

6. CONFERENCES AND WORKSHOPS

CONFERENCES

Session on Flame Models at the 1987 Fall Technical Meeting of the

Eastern Section of the Combustion Institute, Gaithersburg, MD , Nov. 2,

1987. Chaired by R.W. Davis.

Session on Sprays at the 1987 Fall Technical Meeting of the Eastern

Section of the Combustion Institute, Gaithersburg, MD, Nov. 2,

1987. Chaired by C. Presser.

127
Sessions on Fluid Flow Measurement Uncertainty (I and II) at the ASME

Winter Annual Meeting, Boston, MA, Nov. 3-4, 1987. Organized and

chaired by G.E. Mattingly.

Sessions on Reaction Engineering and Combustion Processes and on

New Experimental Techniques for High Temperature Reacting Flows at

the AIChE 1987 Annual Meeting, New York, NY, Nov. 16-20, 1987.

Organized and Chaired by H.G. Semerjian.

Session on Combustion Phenomena at the AIAA 26th Aerospace Sciences

Meeting, Reno, NV, Jan. 11-14, 1988. Chaired by C. Presser.

Session on Sprays/Injectors at the AIAA/ASME/SAE/ASEE 24th Joint

Propulsion Conference, Boston, MA, July 11, 1988. Chaired by C.

Presser

Session on Combustion Fundamentals at the ASME/AXChE National Heat

Transfer Conference, Houston, TX, July 25, 1988. Chaired by H.G.

Semerjian.

Session on Multiphase Combustion Sprays at the 22nd Symposium (Int'l) on

Combustion, Seattle, WA, Aug. 19, 1988. Chaired by H.G. Semerjian.

Session on Trends in Bioelectrochemistry, XII Jena Symposium on

Biophysical Chemistry, Weimar, GDR, Sept. 23, 1988. Chaired by R.D.

Astumian.

WORKSHOPS

Sponsored Workshop on Mechanisms of Interaction of Electric Fields with

Cell Membranes, as part of the BioElectroMagnetics Society Meeting, held

on June 21, 1988, at Stamford, CT. Chaired by A.K. Gaigalas.

Sponsored Workshop on the Role of Cooperative Pheonomena in

Understanding Electromagnetic Field Effects in Biological Membranes,

held on Sept. 7-8, 1988, at Bethesda, MD.

Hosted Two Workshops for the Indus try -Government Consortium on Flowmeter

Installation Effects Research, held on Feb. 17 and Aug. 19, 1988 at

NIST, Gaithersburg, MD. Organized and chaired by G.E. Mattingly.

128
TECHNICAL ACTIVITIES

OF THE

TEMPERATURE AND PRESSURE DIVISION

A. 0 . McCoubrey, Acting Chief

1. INTRODUCTION

The need that is addressed by the Division is accurate measurement of

temperature and pressure throughout the United States on a basis that is

consistent with measurements of these quantities in other industrial nations

of the world. National reference standards for temperature and pressure are

necessary for accurate measurement of these quantities; the program of the

Division is part of the statutory responsibility of NIST to provide the U.S.

national reference standards for measurements and to provide related services

to make such reference standards useful in industry, science, and government.

The CCT/NIST approach to meeting the need for accurate measurements of

temperature and pressure is based upon research to establish the scientific

basis for temperature and pressure reference standards, technical development

to implement such reference standards, delivery of services derived from the

operation of these reference standards, the development of technology to

assist users in the realization of benefits from the services, and

publication of related information.

More specifically, the program of the Temperature and Pressure Division

is focussed upon temperature measurement technology below the pyrometric

range, and pressure measurement technology from pressure levels of several

hundred atmospheres to those that prevail in the most modern state-of-the-art

vacuum systems. The activities within the present program include:

• research directed toward new optical methods for the accurate

measurement of temperature and pressure under dynamic conditions

(millisecond time resolution) and within small volumes (millimeter

dimensional resolution)

• research directed toward the evaluation of the optical fiber

thermometer as an absolute thermodynamic standard thermometer, and

the use of this thermometer as a means to link the pyrometric

temperature scale with the practical temperature scales [IPTS68(75) and the pending ITS -90] at the gold point, the silver point

and, possibly, the aluminum point;

• research to advance the technologies for realizing or maintaining

accurate temperature and pressure scales;

129
• research and development to refine the U.S. National reference

standards for temperature and pressure;

• development to improve the methods for transferring the values of

NIST standards for temperature and pressure to users in industry,

science, and government;

• calibration services and measurement assurance program (MAP)

services to transfer the values of NIST units and scales for

temperature and pressure to users in industry, science and

government

• special test services to support temperature and pressure

measurement needs for which calibration or MAP services are not

established;

• participation in the temperature and pressure related work of the

Consultative Committees of the International Committee of Weights

and Measures

• participation in the temperature and pressure related work of

domestic standards committees;

• development to improve quality control and reduce uncertainties in

pressure calibration services based on dead weight piston gages;

• documentation and publication of research results, methods for

calibration services, and methods for special test services.

Important changes in the thrust of the Division activities related to

temperature scale research have been made during the past year. In October,

1987, the research project to establish a millikelvin temperature scale was

terminated, and the available staff effort was redirected toward noise

thermometry within the range of the new international temperature scale,

ITS-90, and the production of a standard reference material device, SRM-768,

for temperatures from 0.01 K to 0.5 K. In the fall of 1988, very- low

temperature research (noise thermometry and the improvement of SRM-768) was

also terminated, and the resources were again redirected to the development

of facilities for the realization of the new international temperature scale,

for temperatures below the triple point of water. The possibility of

producing a revised version of SRM-768 (relaxed specifications for W and Be

superconducting fixed points) will be considered in the future; the decision

will depend upon user needs for the technology at the present state of

development

2. GOAL

The goal of the Temperature and Pressure Division is to provide the

required NIST services to support measurements of temperature and pressure at

necessary levels of accuracy in industry, science, and government throughout

the United States. This goal is addressed by:

130
• the conduct of research to provide an up to date scientific basis

for national reference standards for temperature and pressure;

• the development and dissemination of efficient and effective

services based upon these reference standards and incorporating

advanced technology as required to minimize cost to users, optimize

quality, and increase accessibility;

• the conduct of research and development to anticipate future needs

in industry, science, and government growing out of emerging and

advancing technologies;

• the conduct of research and development to advance temperature and

pressure measurement technology for the benefit of U.S. industry,

science, and government;

• the production of scientific publications and technical reports to

optimize the availability to users of technical results and methods

from Division programs.

3. GROUP AND PROGRAM FUNCTIONS

The technical activities of the Division are carried out in five groups

and one Division Office program.

GROUPS

• Thermometry Research and Calibration Services - B.W. Mangum, Group

Leader

The program of this Group includes calibrations and related services for

resistance thermometers, thermocouples, thermistors, laboratory thermometers

(mercury in glass), and digital thermometers. The Group also conducts

research and development leading to new thermometric fixed points and

improvements (including automation) of the facilities for the maintenance of

the International Practical Temperature Scale [ IPTS-68 (75)

,

to be replaced by

ITS-90]

• Temperature Scale Development - J.F. Schooley, Group Leader

This Group is responsible for studying optical fiber thermometry as a

metrological tool; for completing the NIST gas thermometry contribution to

the 1990 International Temperature Scale; for assessing the prospects for

utilizing noise thermometry for metrological and industrial measurements

above 0.5 K; and for the preparation and calibration of SRM 767A and 768.

Outputs include data, physical theories and descriptions, and devices.

Principal non-CCT sponsors of the work of this Group include the DoD and the

NIST Office of Standard Reference Materials (OSRM)

131
• Optical Measurements of Temperature and Pressure - G.J. Rosasco,

Group Leader

The Optical Measurements of Temperature and Pressure (T and P) Group

conducts fundamental research into the process of spectral line formation in

order to provide a basis for accuracy in the use of nonlinear Raman

spectroscopies for the determination of T and P. Accurately known conditions

of T, P, and species concentration are established in gas phase systems

significant for diagnostic applications. Reference spectra are measured and

analyzed in terms of line formation theory to determine the limits of

accuracy for T and P measurements. The physical phenomena important in

determining the lineshape function are investigated both experimentally and

theoretically. Lineshape functions are tested and the molecular parameters

which specify these functions are determined. Theories which describe these

molecular parameters as functions of T, P, and composition are developed and

tested. Measurement accuracy is provided in the form of validated,

predictive expressions for the spectral distribution as a function of T, P,

and composition.

A long range objective for this group is the development of a means to

assure the accuracy of measurements of time varying T and P. The approach is

to develop at NIST an accurately characterized source of T(t) and P(t) . The

values of these time varying quantities will be determined by use of the

optical diagnostic technique whose accuracy was established from the research

described above. The dynamic source can serve as the basis of a calibration

service and will allow the measurement of the temporal response of sensors.

• Piston Gage - C.D. Ehrlich, Group Leader

The piston gage is the standard instrument for precise pressure

measurements in the range above the limits of manometry. The instrument

consists of a carefully made piston fitted into a matching cylinder which is,

in turn, connected to a pressure generating system. The piston is loaded

with measured weights, floated by adjusting the cylinder pressure using a

transmitting fluid, and rotated to help attain concentricity of the piston in

the cylinder. This rotation both minimizes the possibility of and aids in

the detection of metal- to-metal contact, which causes unwanted frictional

forces. The pressure is calculated as the ratio of the downward force due to

the weights and the piston, and the 'effective area' of the piston-cylinder

combination. The goal of the Piston Gage Group is to determine the effective

area at atmospheric pressure, (A0 ) , and the change in the effective area with

pressure, with an accuracy sufficient to: (a) provide U.S. piston gage

manufacturers with the needed calibration services to keep their products

competitive in the world market; (b) meet the need for increased accuracy

requested by our calibration service customers, such as the DoE and DoD

laboratories; and (c) participate effectively with other national standards

laboratories in setting international standards for pressure calibrations.

• Low Pressure, Vacuum and Leak Rate - C.R. Tilford, Group Leader

This group develops standards, provides calibration services, and

characterizes instrumentation over twelve decades of pressure from above

132
atmospheric to ultra-high vacuum. Similarly, leak rate (very low flow rate)

standards are maintained and used for the calibration of helium leaks between

10‘® and 10 mol/s. The specialized measurement capabilities of the Group

are used in the development of new measurement techniques and, to a limited

extent, in the determination of material properties. This work has enjoyed

outside support from the DoE Office of Fusion Energy, the Department of

Defense, Sandia National Laboratories, and the NIST Office of Nondestructive

Evaluation.

DIVISION OFFICE PROGRAM

• Nuclear Magnetism - H. Marshak, Research Scientist

This project is concerned with nuclear orientation thermometry for the

realization of a temperature scale in the millikelvin temperature region.

The past year has been devoted to the reduction of experimental data and

writing a number of publications. This work will be completed during the

first quarter of FY89, reflecting the decision to terminate research on the

millikelvin temperature scale.

4. SELECTED PROJECT SUMMARIES

THERMOMETRY RESEARCH AND CALIBRATION SERVICES GROUP

Calibration Services

B.W. Mangum, W. R. Bigge, G. W. Burns, E.R. Pfeiffer, M.G. Scroger, G.F.

Strouse, J.A. Wise

The objectives of this program are (1) to maintain the IPTS-68(75) in

the range 13 K to 1337 K [the region of the scale in which the standard

instruments are the standard platinum resistance thermometer (SPRT) and the

Pt-10%Rh/Pt thermocouple ( t/c ) ]

(2) to make improvements in the realization

of that scale; (3) to disseminate the scale (through calibrations, precision

measurement seminars, MAPs, lectures, publications, interactions with

standards -writing organizations, etc.); and (4) to prepare for implementation

of a new International Temperature Scale. Also, an additional objective is

to maintain the Provisional 0.5 K to 30 K Temperature Scale (EPT-76) and to

provide calibration services based on that scale.

133
The following table outlines the calibration procedures.

13 K to 500 K

78 K to 904 K

904 K to 1337 K

273 K to 2373 K

100 K to 815 K

Capsule SPRTs

Long- stem SPRTs

Type S t/c

Noble, base, and

refractory metal

t/c

Liquid- in- glass

thermometers

,

low temperature

thermocouples

,

thermistors

,

IPRTs,* digital

thermometers

Calibrations by comparison

against reference standards.

Calibrations by comparison

against reference standards

at 90 K and by use of fixed

points (TP of H2 O and

FP of Sn and Zn)

Calibration by comparison

against reference standards

or by use of fixed points

at FP of Zn, Ag, and Au.

Calibration by comparison

against reference t/c.

Calibration by comparison

with SPRT reference standard.

•^Industrial Platinum Resistance Thermometer

During the past year, the Temperature Calibration Group performed many

precision calibrations for domestic industrial and governmental users and a

few for foreign users. Those calibrations provide traceability to the

IPTS-68(75) maintained at the NIST. The following calibrations were

performed:

Service Number of Items

Type 33010C, long- stem SPRT 30

Type 33020C, long- stem SPRT 52

Type 33050C, capsule SPRT 11

Type 33040C, capsule SPRT 2

Type 33120M, SPRT MAP 1, 8 SPRTs

Type 33060C, Rhodium- Iron RT 7

Type 33060C, Germanium RT 3

Thermocouples 240

Liquid- in- glass thermometers 600

Low- temperature thermocouples 22

Thermistors; IPRTs; digital

thermometers 50

134
In conjunction with the rhodium-iron (RIRT) calibrations, it was found

that results on the NIST reference RIRTs over a six-year period indicate that

our original two rhodium- iron reference standards for EPT-76 are stable

within about 0.1 mK with respect to each other and with respect to stable

platinum reference standards. This stability is better than that reported by

most other national standards laboratories.

Thermometric Fixed Point Development

B.W. Mangum, G.T. Furukawa, E.R. Pfeiffer, G.A. Evans, Jr.

During the past year, considerable effort has gone into constructing,

assembling, and evaluating temperature fixed-point cells for use in

calibrating SPRTs , on both the IPTS-68(75) and the soon- to-be-adopted ITS-90.

Experimental problems associated with realizations of some of the new fixed

points of the ITS-90 were addressed also. The work on the fixed points

included:

1. Completed initial testing of five (5) Sn freezing-point cells

(constructed previously) containing 99.9999+% pure metal of SRM 741 and seven

cells of zinc filled with 99.9999+% pure metal of SRM 740.

2. Constructed and tested two Sn and two Zn freezing-point cells containing

99.9999+% pure Zn in shot form from commercial sources and compared results

with Sn and Zn freezing-point cells containing SRM metals. The Zn in shot

form was being evaluated in anticipation of purchasing and certifying new

metal for SRM 740. These four freezing-point cells of tin and zinc were

constructed for commercial firms.

3. Samples of 99.9999+% pure Al and Ag and other freezing-point cell

components were purchased for the construction of cells to be used in an

international comparison with similar cells from the IMGC (Italy) and INM

(France)

4. Two large cells, filled with 1500 g of 99.9999% pure indium in a Teflon

inner container located in a stainless steel outer container, were

investigated and put into use in a new furnace in our PRT Calibration

Laboratory to provide a freezing point to be used as a check point in the

routine calibration of SPRTs. Data obtained on these cells were analyzed and

a paper describing the results of the investigation was written. The

pressure dependence of indium was found to be 48.9 ± 0.5 mK/MPa and the

freezing-point temperature to be 156.6341°C.

5. Freezing and melting curves of eleven borosilicate and two stainless

steel and mercury cells were investigated at their triple points. Seven

borosilicate cells and the two stainless steel cells were sealed over

thirteen years ago. One borosilicate cell was capped but not sealed over the

same period. Three borosilicate cells were recently prepared by vacuum

distilling samples which were stored in capped soft glass bottles. The

earlier measurements on the ten cells, when they were freshly made, showed

freezing ranges of less than 0.1 mK for up to 80% of their freezes. The

freezing ranges of recent measurements on them were 0.1 to 0.2 to over 0.5

mK. The newly made cells also exhibited these broad freezing ranges. Soda

135
lime glass contains Na2 , CaO, MgO, and AI 2 O3 in addition to Si02 l borosilicate glass contains Na2

C> 3 , B2 O 3 , and AI2 O 3 in addition to SiC> 2

. Any

free metals formed by chemical reaction would dissolve in mercury. Although

from the standpoint of chemical equilibria, small amounts of free metals

could form, such reaction seems unlikely since mercury is far below the

metals in the electromotive force series. In the case of the stainless steel

cells, small amounts of nickel are expected to have dissolved in the mercury.

Further analysis of the assembled data is in process. For the mercury triple

point or freezing point, cells of Teflon or other suitable plastics, that are

free of metals, should be tried.

6 . A furnace, electronic control, and power supply for realizing the

freezing point of indium was designed, constructed, and assembled. Tests on

an existing indium cell showed that the freezing point can be reproduced

within 0.1 to 0.2 mK. In a single freeze, the calibration of six SPRTs has

been demonstrated to be repeatable to within about 0.1 mK.

7. Some furnaces used for pre -heating SPRTs close to the temperatures of

calibration prior to their insertion into freezing-point cells were

constructed and additional ones are currently under construction.

8 . The construction of a new apparatus, incorporating an argon triple-point

cell, that is to be used in the calibration of long-stem and capsule SPRTs

neared completion. This apparatus will accommodate seven long- stem SPRTs and

six capsule SPRTs. The external reservoirs (52 St total) for containing the

argon sample were cleaned, assembled, and tested to contain the gas at 900

kPa without leaks . The sample cell proper was assembled with the thermometer

wells and tested for vacuum and pressure (900 kPa) after thermal cycling

three times between room temperature and the liquid nitrogen temperature.

Two of the flanges, where the long- stem SPRTs will be tempered, have been

assembled, and heaters for their respective "cans" have been wound. The

"vacuum flange" was just assembled. Preparations are being made to test the

vacuum containment of the argon triple -point cell and temperature control

shield system. This will be followed with the assembly of the helium heat

exchange manifold for the long-stem SPRT wells. Then, the coupling to the

top flange, from which the entire argon triple-point assembly will be

suspended inside the liquid nitrogen Dewar, will be assembled. When

construction of this apparatus is completed, it will be tested and installed

in the PRT Laboratory, replacing the comparison apparatus currently used at

the oxygen point.

9. Thirteen SPRTs that were found to contain excessive moisture were

examined for possible repair. Eleven were selected for repairs by opening

their hermetic seals, baking, pumping dry, and resealing with dry argon/5%

oxygen gas mixture. Nine of these SPRTs were found unexpectedly to leak.

The leaks were repaired and the external platinum leads were replaced on some

of the SPRTs. The repaired SPRTs were tested to be adequately dry. The

repair process and testing showed that the manufacturers should follow more

stringent quality control. As found in prior work, it was shown that the

annealing process can generate enough water to make the SPRT contain

excessive moisture.

136
Automation. Modernization and Upgrading of the Calibration Laboratories

B.W. Mangum, R.S. Kaeser, E.R. Pfeiffer, G.W. Burns, W.R. Bigge,

G . A . Evans , Jr.

The temperature related calibration laboratories in which the NIST

maintains and disseminates the IPTS-68(75) are being modernized, upgraded,

and semi -automated; this is long overdue. Most of the instrumentation

required for this work has been purchased, but only in the PRT Calibration

Laboratory has any of it been installed and some of the programming done.

The upgrading and automation of the PRT Calibration Laboratory are nearing

completion, but those for the Thermocouple and Liquid- in-Glass Calibration

Laboratories are just beginning.

During calibrations of SPRTs, comparisons have been made between a

manually- operated DC current comparator bridge and an automatic DC pulse

bridge in preparation for automation of the measurement and analysis

processes in the calibration of SPRTs.

Thermocouple Research for the POD Combined Calibration Group

G.W. Burns, M.L. Reilly

With support from the U.S. Navy Metrology Engineering Center, work

continued on the development of a calibration procedure for a commercial

heater probe. This probe was specifically designed to test the thermocouple

harness of specific jet engines. The engines are used in the Navy's VH-IN

helicopter. The heater probe had been previously designated by the Navy as

"difficult to calibrate," due to the lack of a reliable standard.

Extensive tests to develop suitable calibration standards and procedures

for the heater probes were conducted during FY88. The calibration stability

and repeatability of several heater probes and of specially manufactured Type

N and Type K thermocouples were evaluated. The studies included determining

the effects of cycling the heater probes between room temperature and 800° C,

and of heating the heater probes for prolonged periods of time at 800° C. In

addition, the effects on the emf- temperature relationships of Type N and Type

K thermocouples after isothermally annealing them at 750 and 800° C for

periods up to 200 h were measured both in the heater probes and in a

laboratory calibration furnace.

One heater probe, which was manufactured in March 1988 and had not been

used previously, was tested over a four month period during which time it was

cycled 59 times between room temperature and 800° C and was heated for

approximately 500 h at 800°C. The change in its calibration at 800° C did not

exceed 1°C during the test period. Another heater probe, manufactured in

October 1974 and having considerable use since its manufacture, exhibited a

calibration change of about 3°C after four test cycles and about 47 h of

heating at 800° C.

Sheathed Type N thermocouples that had been isothermally annealed for

8 h at 800 °C exhibited emf changes equivalent to about 0.6°C after 200 h of

heating at 800°C at fixed immersions. The results showed that the

137
calibrations of such thermocouples performed by comparison with Type S

reference thermocouples in a laboratory calibration furnace could be

transferred to the heater probes with a total uncertainty of 1.5 to 2°C.

Medical Thermometry

B . W . Mangum , G . A . Evans , Jr.

The goal of this program is to develop a set of fixed temperature points

and a means of using them to calibrate transfer standards for the temperature

region of interest (0 to 200° C) to the medical community.

138
The following table outlines the temperature fixed point program:

Medical Temperature Fixed Points

Material Tf (°C) Status

Indium 156.635 ± 0.002 SRM 1971,

100 cells tested.

Succinonitrile 58.0805 ± 0.0015

Phenol

n- Laurie acid

n-Docosane

Rubidium

Ethylene carbonate

Gallium

40.922

43.95

43.8905

39.303 ± 0.005

36.3238 + 0.0004

29.772 + 0.001

SRM 1970,

115 cells tested,

RSI article

published,

NBS J.Res. paper

SP 260-101 published.

Investigated; good

point, but not SRM.

Investigated; rejected.

Investigated; to be SRM.

SRM 1969,

article published

in TMCSI

,

SP 260-87 published.

Alternative to Rb

paper published in

Metrologia

SRM 1968,

several papers published.

Since there was a special (even critical) need for two temperature fixed

points, at about 41 or 42°C and 44 or 45°C, bracketing the hyperthermia range

used in cancer therapy, an investigation to find and develop such fixed

points was continued. In the NIST study, the freezing/melting behavior of

small cells of phenol, n-lauric acid, and n-docosane was investigated.

Results of that investigation led to the selection of phenol and n-docosane

as the materials for the two fixed points. Based on that investigation,

n-docosane will be produced at the NIST as SRM 1973. The National Cancer

Institute funded some of this work; the NIST Office of Standard Reference

Materials (OSRM) funded the remainder.

139
TEMPERATURE SCALE DEVELOPMENT GROUP

Noise Thermometry Above 0.5 K

W.E. Fogle, J.H. Colwell, R.J. Soulen, Jr. (Guest Researcher), W.E. Bowers

The capability to realize the EPT-76 (0.5 K to 30 K) temperature scale

in the Noise Thermometry Lab was implemented through the introduction of

calibrated thermometers and the SRM 767A device and the associated hardware

and software. The noise thermometer hardware was updated with the

installation of a new data acquisition system, a new frequency counter, and

an uninterruptible power supply. A paramagnetic Curie -law thermometer

capable of use up to 3.5 K was designed and built, along with a specially

designed mutual inductance bridge. These steps will permit the evaluation of

noise temperatures to considerably higher temperatures than before, with

faster data rates and more reliable results.

SRM 768 Production and Calibration

J.H. Colwell, W.E. Fogle, W.E. Bowers

O

The J He melting- curve apparatus used for precise temperature registry

has been improved in order to facilitate its use in determining the absolute

values of temperature for the superconducting transitions of the SRM 768.

The existence of proximity effects in the beryllium transitions has been

pursued as a means of providing the user with a better technique for their

employment in precision thermometry. The international intercomparison of

SRM 768 devices with Dutch and West German laboratories as a means of

intercomparing their present realizations of temperature scales in the range

0.01 K to 0.5 K has progressed to the point of exchanging specially-prepared

devices

Installation of User-Facility Dilution Refrigerator

J.H. Colwell, W.E. Bowers

A surplus -^He-^He dilution refrigerator has been installed. The

apparatus, capable of maintaining temperatures as low as 0.015 K on a

continuing basis, has been utilized by guest workers from MIT and elsewhere

(A. Drukier, T. Girard, and their collaborators) for the study of massiveparticle detectors based upon superconductivity.

Analysis of Sapphire Optical Fiber Probes

M.L. Reilly, S.J. Pang (Guest Researcher)

Careful study of three commercial sapphire optical fiber probes has

elucidated the problems in their use in metrological-quality radiation

thermometry. Experiments performed include light scattering and absorption.

Both properties are temperature dependent. Further studies show unexpected

reactivity of sapphire with the constituents of Inconel protective sheaths,

140
forming islands of Cr, Ni, and Fe oxides on the fiber surfaces. Talks on

optical fiber thermometry were presented to the ASTM E-20 Committee and to an

ASTM Workshop on Temperature Measurement.

Analysis of Thermocouple Test Units

M.L. Reilly, G.W. Burns

Automated data acquisition and analysis techniques were perfected and

utilized for the study of thermocouple -Dased test harnesses on behalf of the

U . S . Navy

Thermodynamic Temperatures in the Range 0°C to 660° C By Gas Thermometry

J.F. Schooley, R.E. Edsinger (Guest Researcher)

Thermal expansion measurements were made and analyzed on several samples

of the NBS Gas Thermometer working bulb, permitting the final calculation of

kelvin thermodynamic temperatures in the range 230° C to 660° C. These were

compared to the values obtained on the 1968 International Practical

Temperature Scale. The results were presented in a paper submitted to the

journal "Metrologia" and in a talk before the National Conference of

Standards Laboratories.

Production and Calibration of SRM 767A Devices

J.F. Schooley, G.A. Evans, Jr., R.J. Soulen, Jr. (Guest Researcher)

With support from the NIST OSRM, a fresh supply of SRM 767A devices was

prepared and calibrated. In addition, the first experiments were performed

to study the suitability of several types of high transition- temperature

superconductors for the 767A device.

OPTICAL MEASUREMENTS OF TEMPERATURE AND PRESSURE GROUP

G.J. Rosasco, W.S. Hurst, J.P. Looney, W.J. Bowers

The determination of the temperature and J dependence of the line

broadening coefficients for CO: CO has been completed. A modified exponential

gap (MEG) law has been shown to account for these data. This law is being

tested against our recent measurements of the collisional collapse of the

Q-branch in the range 0.1 to 1 MPa and 295-1000 K. Line shifting as a

function of J and T has been determined for CO: CO (and addditionally for

N2 :N2 ) over this same range of T and P. The latter data are necessary in

order to accurately model the collisional collapse. A reliable predictive

basis should be completely specified by the end of FY89.

A paper describing the spectral lineshapes for simultaneous forwardbackward scattering in a multipass cell has been prepared. In the course of

these studies, evidence for the applicability of the soft collision model for

describing the combined effects of velocity and phase changing collisions in

D2 :D2 and D2 :He has been obtained. Similar measurements of D2 :Ar have

revealed new features not predicted by any known theory for the spectral

141
distribution arising from the combination of velocity and phase changing

collisions. Theoretical investigation and further experimentation are

planned for this important and novel system.

Experiments and preliminary analysis of the temperature (300-1000 K) and

pressure (0.1 to 5 MPa) dependence of the self -broadened H2 Q-branch have

been completed. Both phase and velocity changing collisions play an

important role in this spectrum. The temperature and J dependence of the

line shifting also has been determined. The analysis to this point has shown

that the line broadening can be explained by a combination of a temperature

dependent vibrational dephasing contribution and a MEG law based description

of the rotationally inelastic portion of the linewidth. The velocity

changing collisions in the pressure regime of interest are typically

described by an effective optical diffusion coefficient. At room temperature

this coefficient is almost equal (within 3%) to the mass (self) diffusion

coefficient. Preliminary indications from our measurements are that the

optical diffusion coefficient deviates markedly from the mass diffusion

coefficient at elevated temperatures. Verification and further elucidation

of the temperature dependence of this important contribution to the linewidth

will be concluded in FY89. In addition to their importance in propellant

diagnostic studies, we are interested in the pure hydrogenic and hydrogenic

mixed gas systems because of their potential use as working media in

generators of rapidly varying temperature and pressure.

PISTON GAGE GROUP

Piston Gage Calibration Services

V.E. Bean, J.W. Behrens, R.G. Driver, C.D. Ehrlich, W. Markus, D.B. Ward,

B.E. Welch, J.C. Houck (Contractor)

The Piston Gage Calibration Service has significantly increased its

workload (and income) for the second straight year; it is up 43% in workload

over the previous year's comparable increase. These increases are largely

due to our accommodating the major U.S. manufacturer of piston gages and the

U.S. Air Force by providing approximately 100 additional gas-operated

piston/cylinder calibrations from June 1987 to June 1988. Fortunately this

workload has now been reduced by demonstrating that the quality control of

the manufacturer is quite good, thereby eliminating the need by the Air Force

for 100% NIST calibration. We will be looking to reduce our calibration

workload even further by encouraging users to go to secondary calibration

sources whenever feasible, perhaps by participating in MAP programs with

selected laboratories. This will free up NIST personnel to spend more time

recalibrating our own primary and secondary standards, training new

personnel, and bringing newly acquired primary standards on-line. However,

this will have the drawback of reducing calibration income, and perhaps tying

up a significant amount of staff time in the MAP program itself.

142
A breakdown of FY88 calibrations is given in the following Table:

Service Quantity

Gas piston gages

Gas piston gages (special)

Gas transducers

36

80

2

Oil piston gages

Controlled- clearance

35

piston gages

Bourdon tubes

1

1

155

Transfer of Gas Piston Gage Calibration Service

Primary Standard Support to Manometry

V.E. Bean, R.G. Driver, C.D. Ehrlich, B.E. Welch, J.C. Houck (Contractor)

Collaborators: R.E. Edsinger, L.A. Guildner

Significant progress was made toward reducing the reported uncertainties

and refining the effective area values associated with the gas piston gage

calibration service. Work reported in the past concerning the calibration of

four gas piston gages against the Gas Thermometer Manometer was carefully

evaluated, and uncertainty estimates were derived. As this work was

performed in the absolute mode of operation (the region above the piston is

evacuated) , and whereas most of the gas piston gage calibration work is

performed in the gage mode of operation (the region above the piston is at

nominal atmospheric pressure) , it was necessary to obtain information

concerning the additional uncertainty in going from the absolute to the gage

mode. An upper bound on this uncertainty was obtained as a result of

calibration of two gages against the Ultrasonic Interferometer Manometer,

coupled with cross-floats of pairs of the original piston gages, which

demonstrated differences in effective area as a function of mode of operation

and gas species. Combining this upper bound with the absolute mode

uncertainties, it was then possible to establish gage mode uncertainties for

the original set of piston gages.

The transfer of these effective areas and uncertainties to the new gas

piston gage calibration bench has begun. J. Houck and G. Driver have

performed calibrations and intercomparisons between several of the new and

old gages and one of the gages recently calibrated against the NIST Gas

Thermometer Manometer. Using two nominally identical gages in each pressure

range allows these calibrations to continue in a ladder- like fashion, so that

uncertainties can be assessed at higher gas pressures as time goes on. The

goal here is to have new effective areas and uncertainties in place, at least

to 4 MPa, in FY89.

143
Piston Gape Quality Control Initiative

V.E. Bean, J.W. Behrens, R.G. Driver, C.D. Ehrlich, W. Markus, D.B. Ward,

B.E. Welch, J.C. Houck (Contractor)

With increased customer demands for lower uncertainties, more overlap of

calibration ranges, and improved documentation in the Piston Gage Calibration

Service, several steps were taken to address these issues. Reducing

uncertainties for the gas service is discussed above, while some comments

concerning the oil service will be addressed below in the section on

Distortion. In addition, however, as part of an effort both for ourselves

and our customers, and aimed at reducing uncertainties and providing better

overlap and quality control, two sets (from different manufacturers) of

'’simple" piston gages have been ordered. These gages can be treated as

either primary standards or secondary standards, and when used in conjunction

with controlled- clearance piston gages will provide a means of evaluating the

uncertainties associated with the calculation of distortion coefficients.

They will also provide an additional means of verifying the stability of our

own working standards.

Other efforts in the area of quality control include instituting a

program to routinely calibrate the masses used in the calibration services,

putting a large amount of information pertaining to calibration of our own

instruments into spreadsheet files for ease in evaluation and access, and

upgrading our own documentation. The spreadsheet files will aid in our

ability to generate control charts of various sorts in a more efficient

manner. The goal is to eventually computerize the entire piston gage data

base. We are also working to bring the program that is used to analyze the

raw data from a cross -float over from the NIST mainframe computer to a PC.

Difficulties have been encountered in getting parts of the statistical

program to run satisfactorily on the PC, but the NIST Statistics Division is

working with us and we will hopefully overcome this difficulty soon. Our

recently developed calibration documentation is being upgraded to include a

section outlining the quality-control steps indicated here, as well as a

section that provides more detail about the analysis that goes into a NIST

piston gage calibration report. We are still reviewing this report and may

soon switch to a new data reduction technique.

BIPM Gage Intercomparison

V.E. Bean, C.D. Ehrlich, B.E. Welch

A major effort this year has been the calibration of a piston gage to be

used in an international round robin organized by the BIPM (International

Bureau of Weights and Measures) Consultative Committee for Mass and Related

Quantities Working Group on Medium Pressure. This gage was calibrated in

both the gage and absolute modes over the pressure range 11 kPa to 131 kPa

both by the Pressure Group and the Vacuum Group, giving an excellent

opportunity for absolute comparison between the two groups. Although all of

the data are not fully evaluated, initial indications are that the agreement

is well within the combined uncertainties of the two sets of measurements.

144
Distortion of Piston Gages at High Pressure

V.E. Bean, C.D. Ehrlich, D.B. Ward

As pressure increases, the leading source of uncertainty in pressure

measurement is a lack of knowledge of how the effective area of the piston

gage changes with pressure. Published results of a piston gage

intercomparison in the pressure range of 20 to 100 MPa, with LNE, PTB, IMGC,

NPL, and NIST participating, demonstrated a lack of agreement among these

national laboratories in determining the pressure coefficient of the

effective area of the transfer- standard piston gage used in the

intercomparison. PTB, IMGC, NPL and NIST have initiated research programs to

re-examine piston gage distortion. In brief, the NIST program is to:

(1) Develop the capability of calculating the distortion from

theory that is amenable to a satisfactory error analysis.

(2) As a test of the calculations:

a) Measure the change with pressure of the outer diameter of

the cylinders for two piston gages which are made of

different materials and compare with the calculations;

b) Cross -float these two piston gages and compare the ratios

of the effective areas with the calculations.

There are two challenges in developing appropriate calculational

methods

(1) Existing theories do not have ways of estimating errors due to

simplifying assumptions.

(2) Values for the pressure gradient in the annulus between the

piston and cylinder are necessary input parameters for the

calculations. We have demonstrated that the pressure gradient

can be calculated from the dimensional clearance between the

piston and the cylinder. However, obtaining adequate

dimensional data is a nontrivial problem.

Obtaining the data to test the calculations is straightforward in that

we have developed a very good method of measuring the change with pressure of

cylinder outer diameters.

Currently we are examining the applicability of finite element analysis

software to this problem. We are also collaborating with IMGC on both

calculational and experimental methods

High-Pressure Transducer Characterization

V.E. Bean

There is a need for a stable and sensitive pressure transducer capable

of operating in the 700 MPa pressure range for experimentally determining the

cylinder deformation coefficients for controlled- clearance primary standard

piston gages and for pressure measurement intercomparisons among

145
laboratories. Transducers based on the electrical resistance of a length of

commercial wire are used for intercomparisons, but lack the necessary

sensitivity needed to characterize a controlled-clearance piston gage.

During this past year we have developed a new method of measuring this

cylinder deformation coefficient using a transducer made of a single crystal

of InSb. The calibration equation for the transducer is of the form

P = A ln(R/R0 ),

where P is the pressure, A the calibration coefficient, R the resistance at

pressure, and R0 the resistance at atmospheric pressure. This transducer has

the fortunate and unusual feature that the sensitivity increases as the

pressure increases. At 700 MPa the sensitivity of the InSb transducer is 70

times that of the wire- transducer . During this year we have used this new

InSb transducer to characterize five controlled-clearance primary standard

piston gages including gages for India, Taiwan, DOE, and NIST.

We do not yet have enough long-term data to evaluate this transducer as

a transfer standard, but this study is under way.

LOW PRESSURE. VACUUM AND LEAK RATE GROUP

Calibration and Test Services*

S. Dittmann, C.D. Ehrlich, R.W. Hyland

The number of calibrations and special tests increased significantly in

all areas, and significant delays were encountered in completing this work.

The calibration and test services within this Group are relatively new, some

having been started or extended in scope last year, and many of the

industries served are in rapidly changing fields where the instrumentation,

process control requirements, and quality control procedures are in a state

of flux. These factors make it difficult to predict demand for NIST

services. At the same time, our primary standards and some of the transfer

standards are still in a state of development, and staff and equipment must

be shared between the calibration services, extension of range and

improvement of accuracy of the standards, and research to understand the

transfer standards that we and our customers rely on.

The NIST Ultrasonic Interferometer Manometer (UIM) was used in the low

and medium vacuum range to calibrate 33 transducers (primarily capacitance

diaphragm gages) for outside and internal use (major internal use is in our

primary high vacuum and leak standards) . Timely completion was frustrated by

the delayed start of a major remodeling of the manometry laboratory.

Demand for the calibration of spinning rotor gages (SRG, a high vacuum

molecular drag gage) increased to 28 units, and 3 ionization gages were

calibrated below 10"^ Pa. With the increased availability of calibrated SRG

transfer standards , r the demand for ion gage calibrations had almost

disappeared. However, with the extension of our calibration range to 10" ^

146
Pa, and the development of ultra-high vacuum processing techniques in the

semiconductor industry, there appears to be an increased interest in low

range ion gage calibrations. Unfortunately, in addition to the increased

calibration load, a mechanical problem in part of our primary standard

coincided with an unstable let of SRG balls (sensors) . Two months of

additional data were required in order to separate the problems with the

primary standard from those caused by the unstable SRGs and verify

satisfactory operation of the primary standard.

Our new Special Test Service for helium leaks completed seven tests last

year and ten this year. Most of these leaks were near the bottom end of our

calibration range, 10"

^

mol/s.

Progress was made in completion of the writing and editorial review of

documentation for the low and medium vacuum and high vacuum calibration

services

* (Note: 1 atm = 100 kPa, 1 Torr = 133 Pa,

1 atm cc/sec = 5x10" ^ mol/s)

UIM Development and Evaluation

R.W. Hyland, F.G. Long, D.R. Martin, C.R. Tilford, S.S. Hong (Guest

Researcher)

The Ultrasonic Interferometer Manometer (UIM) was originally developed at

NIST as a high- resolution low- range pressure standard. It is a mercury

manometer utilizing an ultrasonic phase measurement technique to achieve a

length resolution of 10"-* mm (one std. dev.). It proved to be flexible and

easy to use, and demonstrated part per million (ppm) reproducibility at

higher pressures. This prompted continued development to extend the range

and reduce the uncertainty. In the latest phase of this development three

new UIMs have been constructed, one with a range of 160 kPa for Sandia

National Laboratories, and two with ranges of 350 kPa for NIST and the Navy

Metrology Engineering Center. The three new instruments incorporate

significant changes in the mechanical design, radio frequency electronics,

and the computer control and data acquisition system. We are still

experiencing mechanical noise problems with the 350 kPa design, which has a

2.8 m mercury column, but the new electronics, computer system, and Sandia

manometer work very well and have been in daily use at NIST for over six

months, with delivery awaiting preparation of new laboratory space at Sandia.

Completion of a measurement of the speed of sound in mercury two years

ago allowed a major reduction in the uncertainty of the UIMs. This prompted

a major reexamination of the possible errors this past year, including

several experiments to evaluate random errors and systematic nonlinearities.

We have concluded that a conservative estimate of the uncertainty at the

three standard deviation level is 15 ppm. A major part of this uncertainty

(6 ppm) accounts for systematic differences between different UIMs. We

believe that these differences are due to diffraction of the ultrasonic beam

propagating up the mercury column.

147
Our confidence in our uncertainty analysis has been bolstered by several

comparisons of the UIM with standards in other national laboratories. In

early 1988 we participated in an international comparison of pressure

standards between 10 and 140 kPa, organized under the auspices of the BIPM.

The UIM results were the seventh set to be submitted and agree well within

combined uncertainties with results from The National Physical Laboratory,

Teddington, The International Bureau of Weights and Measures (BIPM), Paris,

and the National Institute of Metrology, Paris. The UIM results have the

smallest random errors of any of the results yet submitted. Separate

comparisons with the National Engineering Laboratory, Lower Hutt; the

National Physical Laboratory, New Delhi; and the Institute of Metrology,

Torino, have given similarly satisfying agreement.

Evaluation of gas -operated piston gages used as reference standards by

our Pressure Group has also demonstrated agreement of the UIM and the

independent piston gage standards to well within the combined uncertainties.

However, results for different gases show small systematic differences that

are within our total uncertainty, but larger than we would expect when only

the operating gas is changed. This small discrepancy has yet to be resolved

Triple Point Pressures

C.R. Tilford, C. Sutton (Guest Researcher)

The improved measurement of triple point pressures presents an

opportunity to develop needed pressure fixed points and apply our pressure

measurement expertise to the determination of thermodynamic properties. The

primary limiting factor of existing triple point measurements is the

correction for hydrostatic pressure differences between the cold triple point

cell and the room temperature standard. A cryostat with a horizontal

pressure line between the cell and the standard was designed and built.

Argon was selected as the first material to be measured and preliminary

measurements were made using an ultrasonic interferometer manometer as the

standard. The measurements were in good agreement with the best of the

published values, but were flawed by a significant change in the pressure

with melt fraction. This change could be due to impurities, but most likely

indicates excessive temperature gradients between the multiple heat shields

required to achieve isothermal conditions at the triple point cell. Further

work on this project has been deferred in favor of other priorities.

Gas -Operated Piston Gage Evaluation

R.W. Hyland, C.R. Tilford, R. Mangezhani (Guest Researcher), Y.T. Sheng

(Guest Researcher)

While liquid column manometers may be unexcelled for ultimate accuracy

and ease of use, they are expensive and subject to environmental and operator

perturbations. Piston gages, pressure balances, or deadweight testers are

much simpler, cheaper, and less subject to external perturbations. They are

generally used at higher pressures , but a program has been under way in the

148
Pressure Group to develop their use as part per million (ppm) transfer or

reference standards for gas pressures in the range near atmospheric pressure.

In the course of this work, B.E. Welch discovered that a common assumption,

that the operation of these gages is independent of gas or mode of operation

(gage or absolute) , could be in error by as much as 30 ppm. Piston gage

measurements made in the course of evaluating ultrasonic interferometer

manometer (UIM) stability further gave the unexpected result that the

effective area of a piston gage can change by up to 30 ppm at low pressures

in the absolute mode of operation. Until the reasons for these effects are

understood it will be very difficult to achieve the goal, desired by a number

of users, of using these gages as transfer standards at the 5 to 10 ppm

level

We have used the UIM, which serves as a reference standard independent

of gas species or mode of operation, to further investigate these effects.

We have found systematic differences between the absolute and gage mode

effective areas of up to 25 ppm, and have seen, as did Welch, dependencies on

gas species of the effective area for stainless steel pistons and cylinders

of up to 25 ppm. However, we have not seen dependencies on gas species for

tungsten carbide pistons and cylinders greater than 2 or 3 ppm. These

effects are clearly due to changes in the transfer of momentum or force

between the gas flowing in the annular space between the piston and cylinder

and the piston surface. The changes at low absolute pressures are probably

due to the transition between molecular and viscous flow in the annular

space. The dependencies on gas species may be due to surface roughness and

different tangential momentum accommodation coefficients. However, at this

time a consistent pattern in behavior from gage to gage is not apparent, and

the way is not yet clear to the development of a first-principle theory.

Development of Primary Vacuum Standards and Measurement Techniques

S. Dittmann, A.R. Filippelli, F.G. Long, D.R. Martin

The operating range of our primary vacuum standard has been progressively

extended to lower pressures by incremental improvements and the development

of new operating procedures, followed by a careful uncertainty analysis. To

date, this has extended the lower limit of routine measurements from 10"^ to r 10 Pa. Analysis of a set of very low pressure ion gage measurements during

this past year indicates that we can determine the sensitivity of vacuum

gages with an adequate uncertainty (on the order of 5%) down to 10'^ Pa for

nonreactive gases. However, significant problems were encountered with

hydrogen due to the generation of atomic hydrogen at the hot filaments of the

gages. Furthermore, at these pressures the determination of the sensitivity

is of limited use for most gages unless we can also determine the gage's

residual current. Unfortunately, the base pressure of our calibration

chamber is about 10 Pa, not adequate for residual current determination,

and our efforts to reduce the base pressure have met with very limited

success. We expect to build and evaluate a separate ultra-high vacuum system

that we hope will reach 10

p

a . if this can be used to determine residual

currents, then we will probably extend the range of our calibration service.

149
For several years we have granted modest support to a project in B.F.

Kendall's laboratory at Penn State to develop a standard using the Brownian

motion of a levitated particle. This work has recently taken a somewhat

different direction, having successfully measured pressures in the high

vacuum range using the decrement of vibration amplitude of small levitated

metal spheres. Preliminary analysis indicates that this gage may be useful

in the ultra-high vacuum range, where it would have the major advantage of

not requiring a hot filament. This may provide an alternative method of

extending the range of our standards to lower pressures.

Leak Rate Standards

C.D. Ehrlich, R.W. Hyland, D.B. Ward

While there is a definite demand for the extension of our leak rate

standard to below our present limit of 10" ^

mol/s, progress in this area has

been greatly impeded by the assignment of major additional responsibilities

to C. Ehrlich. Our present lower limit is set by the increase of our

uncertainties to 10%. There is some possibility that as we gain experience

in the calibration of slow leaks we can reduce this uncertainty and extend

our range somewhat. In the interim, the Special Test Service is being

maintained, we are building a quality control data base, and an experiment is

proceeding to determine the linearity of our leak comparator system so that

it can play a larger role in our calibration program.

There is also a demand for leak calibrations for gases other than

helium, the only gas for which we presently calibrate. Extension to other

gases requires increased confidence in capillary and orifice type leaks. We

are starting to obtain a limited amount of performance data on such leaks.

Characterization of Vacuum Gages

S. Dittmann, A.R. Filippelli

In order to meet demands to extend the range to lower pressures and

improve the accuracy of vacuum measurements, it is necessary to better

understand the performance characteristics of vacuum gages. As part of this

effort we continued to evaluate the performance of the Spinning Rotor Gage

(SRG) , a new commercial gage that utilizes the molecular drag on a levitated

rotating ball. The SRG is finding increasing use as a high vacuum

calibration or transfer standard, where long term stability is critical.

Evidence to date had indicated that with proper care the balls would not

change by more than 1 or 2% over a one to two year period. We were therefore

surprised to see one group of balls, sent in for calibration by a gage

manufacturer, change by 0.5 to 2% when they were baked.

At this time the only gage available for measurements below the high

vacuum range is the workhorse ionization gage. We have previously documented

significant performance differences in the high vacuum range between

different ion gage* designs , including significant nonlinearities in some

150
designs. If these nonlinearities extend into the ultra-high vacuum range,

vacuum calibrations will be greatly complicated and accuracies reduced. This

past year we experimentally evaluated the linearity of several different ion

gage designs down to 10"® Pa, where our measurements were limited by random

errors in our primary standard and the ion current measurements. These

indicate that for all but one of the 16 gages, the nitrogen and helium

sensitivities were constant within 2 to 3% for pressures up to 10"® Pa.

Hydrogen data showed systematic trends at low pressures, but we believe these

indicate pressure perturbations caused by chemical reactions with atomic

hydrogen formed at the hot filaments , and do not indicate changes in the

fundamental gage sensitivity.

Partial Pressure Analyzer Calibration Techniques

A.R. Filippelli, L.V. Lieszkovszky (Guest Researcher)

In many vacuum processes, particularly at lower pressures, a

measurement or control of specific gas species is more important than that of

the total pressure. Mass spectrometer instruments, generally known as

residual gas or partial pressure analyzers, are widely used for vacuum system

analysis and process control. With the increased emphasis on quality control

there is a corresponding increase in calibration requirements for these

instruments. In order to help determine how complicated the calibration

procedures must be, we have been evaluating different commercial instruments

for the dependence of their sensitivity on pressure, time, instrument

operating parameters, and background gas. To date, this has been done only

for helium, nitrogen, and argon. For the best of the instruments, the

sensitivity is constant within 10% with reasonable variation of these

parameters; for the worst, the changes are two to three orders of magnitude

larger. There are indications that some of the problems with poorly

performing instruments originate in the ion source. But we do not yet know

how many of the problems are generic to a design and how many are specific to

a particular instrument.

DIVISION OFFICE PROGRAM

Nuclear Orientation Thermometry

H . Marshak

This year was almost entirely devoted to finishing up the research work

on the rare earth terbium. In addition to writing five papers, a

considerable amount of time was spent analyzing data for these papers. Most

of this data analysis was carried out using the NIST computing system. The

last large paper should be completed soon. This work on terbium, which was an

international collaboration between NIST, Freie Universitat Berlin, and Bonn

Universitat was not only very productive, but also laid the ground work for

further work on other rare-earth systems. In particular, the on-line low

151
temperature ion implantation groups (Leuven, Belgium; Daresbury, England;

CERN-Geneva, Switzerland; and Oak Ridge, Tennessee) will no doubt do

implantations on other rare earths.

In addition to the publications mentioned above and listed in

"5. PUBLICATIONS 11 herein, some of this work was used in the Ph.D. thesis

(Static and Dynamic Nuclear Orientation Studies on Rare-Earth Systems) of P.

Roman (Freie Universitat Berlin) . His thesis was graded magna cum laude and

H. Marshak served as unofficial adviser.

Also this year, contributions were made to a final report prepared for

NATO on our collaborative (NIST with Universitat Bayreuth, W. Germany;

University of British Columbia, Canada; Kernforschungsanlage Julich, W.

Germany) work to measure the %e superfluid transition temperature (Tpj using

nuclear orientation thermometry. NATO supplied travel funds to carry out

this work. We hope to write a short paper on some of the results in the near

future

5. PUBLICATIONS

Bean, V.E. and Lin, Y-P, On the problem of piston gage distortion, Proc. of

BIPM Symp. on High Pressure Measurement, Paris, France (May 1988) (in

press)

Bignell, N. and Bean, V.E., A fixed point on the pressure scale: carbon

dioxide vapor pressure at 273.16 K, Metrologia, Vol. 25, p. 141 (1988).

Bignell, N. and Bean, V.E., The ^0(1) -H20(XII) -H20(L) triple point of water

as a fixed pressure point, Metrologia (submitted).

Brewer, W.D. , Roman, P. Bottcher, M. , Illerhaus, B. , Marshak, H. , Freitag, K.

and Herzog, P. , NMR on oriented rare-earth nuclei in rare-earth hosts:

application to ^®Tb , Phys . Rev. B1 (in press).

Brewer, W.D. , Roman, P. and Marshak, H. , Precision nuclear orientation

measurements for determining mixed dipole magnetic/electric quadrupole

hyperfine interactions, Hyp. Int. (in press).

Davis, R.S. and Welch, B.E., Practical uncertainty limits to the mass

determination of piston gage weight, J. Res. Nat. Bur. Stand. (U.S.)

Vol. 93, No. 4, pp. 565-571 (July-Aug. 1988).

Dittmann, S., High vacuum standards at the National Bureau of Standards,

Proc. of 1988 Workshop and Symp. of the Nat. Conf. of Stand. Lab., pp

57-1 to 57-14 (Aug. 1988).

Dittmann, S., NIST measurement services: The National Institute of Standards

and Technology high vacuum standard and its use, NIST SP 250-34 (in

press)

152
Edsinger, R.E. and Schooley, J.F., Gas thermometric determination of T(KTTS)

vs. T(IPTS-68) in the range 230°C to 660°C, Metrologia (in press).

Ehrlich, C.D., Present status of the leak standards program at the National

Bureau of Standards - 1988, Proc . of the 1988 Nat. Conf. of Stand. Lab.

Workshop and Symp., pp. 9. 1-9. 4 (Aug. 1988).

Filippelli, A.R. , A brief review of some recent sensitivity and residual

current measurements for several commercial ionization gauges, AIP Conf.

Proc., Vol . 171, p. 236 (1988).

Hyland, R.W. , NIST measurement services: pressure calibration in the range 1

to 150,000 Pa, NIST SP 250-35 (in press).

Mangum, B.W., NBS measurement services: platinum resistance thermometer

calibrations, Nat. Bur. Stand. (U.S.) SP 250-22 (Oct. 1987).

Mangum, B.W., International temperature scales, ASTM Standardization News,

(May 1988).

Marshak, H. , Brewer, W.D. , Roman, P. , Klein, E. , Freitag, K. and Herzog, P.

,

Nuclear double resonance of Tb : l^Tb oriented at low temperatures,

Phys . Rev. Lett., Vol. 59, p. 1764 (1987).

Marshak, H. , Brewer, W.D., Roman, P. and Bottcher, M. , ^^^TbTb(sc) : a new

absolute nuclear orientation thermometer for use in high magnetic

fields, Jap. J. Appl. Phys., Vol. 26 (Supplement 26-3), p. 1737 (1987).

Marshak, H. , Brewer, W.D. and Roman, P. , Magnetization of single-crystal

terbium at very low temperatures by nuclear orientation, Hyp. Int. (in

press)

Marshak, H. , Brewer, W.D. and Roman, P. , Nuclear orientation of l^Tb in pb

single crystal, Phys. Rev. C (to be submitted).

Marshak,. H. , Brewer, W.D. and Roman, P. , Nuclear orientation of the rareearth system *-°^TbTb(sc) , Hyp. Int. (in press).

Reilly, M.L. (co-author), Types of radiation thermometers, Chap. 5 in book,

Handbook of Radiation Thermometers, ASTM (in press).

Rubinstein, E. , Glicksman, M.E., Mangum, B.W. , Fang, Q.T. and Singh, N.B.,

preparation of multistage zone -refined materials for thermochemical

standards, J. Cryst. Growth, Vol. 89, pp. 101-110 (1988).

Tilford, C.R., The speed of sound in a mercury ultrasonic interferometer

manometer, Metrologia, Vol. 24, p. 121 (1987).

Tilford, C.R., International comparisons of pressure standards: a status

report, J. Res. Nat. Bur. Stand. (U.S.) Vol. 93, p. 545 (1988).

153
Tilford, C.R., Dittmann, S. and McCulloh, K.E. , The National Bureau of

Standards primary high-vacuum standard, J. Vac. Sci. Technol. A.,

Vol . 6, p. 2853 (1988).

Tilford, C.R. , New developments in barometric range pressure standards, Proc

of 1988 Nat. Conf. of Stand. Lab. Symp. and Workshop, pp . 35-1 to 35-15

(Aug. 1988).

Tilford, C.R. and Hyland, R.W. , The NBS ultrasonic interferometer manometer

and studies of gas operated piston gages, Proc. of IMEKO XI, 11th World

Congress of the Int. Measurement Confederation, pp . 277-289 (1988).

Tilford, C.R. and Hyland, R.W. , Non geometric dependencies of gas-operated

piston gage effective areas, Proc. of High Pressure Working Group,

Paris, France (May 1988), BIPM Monograph (in press).

Welch, B.E., Edsinger, R.E., Bean, V.E. and Ehrlich, C.D., Observations of

gas species and mode of operation effects on effective areas of gasoperated piston gages, Proc. of BIPM Symp. on High Pressure Measurement,

Paris, France (May 1988).

Wise, J.A., Liquid- in- glass thermometers. Why are they still being used

today?, ASTM Standardization News (May 1988).

Wise, J.A. and Soulen, R.J., Jr., excerpts from NBS Monograph 174,

Thermometer calibration: a model for state calibration laboratories,

Measurements and Control (Sept. 1988).

Wise, J.A., NIST measurement services: liquid- in-glass thermometer

calibration service, NIST SP 250-23, (Sept. 1988).

6. CONFERENCES AND WORKSHOPS

CONFERENCES

Four Invited Sessions of the March, 1988, meeting of the American Physical

Society, held in New Orleans, LA, were organized by the Executive Committee

of the APS Instrument and Measurement Science Topical Group, J.F. Schooley

Vice-Chairman. Schooley chaired one of the sessions.

WORKSHOPS

Two training workshops on the Calibration of Ionization Gages Using the

Spinning Rotor Gage were held in Gaithersburg, MD, during the week of

May 9, 1988. Both were organized by Sharrill Dittmann.

154
NBS-114A (REV. 2-8C) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

4. TITLE AND SUBTITLE

1. PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. 3. Publ i cation D ate

NISTIR 88-3907 December 1988

Center for Chemical Technology

1988 Technical Activities

5. AUTHOR(S)

J. Hord, Acting Director, CCT

7. Contract/Grant No.

8. Type of Report & Period Covered

10-1-87 to 09-30-88

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

6. PERFORMING ORGANIZATION (If joint or other than N BS. see in struction s) National Institute of Standards and Technology

-B-H -R€-A-0-e^"S =F AN-B-A-R-B-5 DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. SUPPLEMENTARY NOTES

3 Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most si gnifi cant information. If document includes a sign ificant

bi bl iography or literature survey, mention it here)

Technical research activities performed by the Center for Chemical Technology during

the Fiscal Year 1988 are summarized herein. These activities include work in the

general categories of measurements (standards, processes, and equipment design),

properties (thermophysical, thermochemical, and kinetic), and biotechnology (protein

engineering and separations). They embody: development and improvement of measurement

standards, measurement principles, and calibration services for pressure, temperature,

volumetric and mass flow rates, liquid volume and density, humidity, and airspeed;

generation (via accurate measurements and advanced predictive models) of reliable

reference data for thermophysical, thermochemical, and kinetic properties of pure

fluids, fluid mixtures, and solids of industrial and environmental importance; provision of fundamental understanding of protein structure-function and advanced

technology for commercial scale separation of proteins; and development of improved

correlations, models, and measurement techniques for complex flows, heat and mass

transport, mixing, and chemically reacting flows of interest in modern unit operations .

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) biotechnology; calibrations; chemical engineering; chemistry; data; flow; fluid properties; kinetics; measurement standards; pressure; process measurement; sensors; separations; solid properties; temperature; thermochemistry; thermophysics; unit operations

13. AVAILABILITY 14. NO. OF

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