bluuebunny/crossref_metadata_2025 huggingface dataset:
Case History, Honeywell Inc.
Authors: Foster LW
Published: March 2009

Honeywell as a multinational company has been involved with the metric system, as applied to its worldwide products and marketplace, for some time. However, a new generation involvement with the metric trends in the United States in the late 60's and increased emphasis on internationalization has motivated Honeywell into a formal metric transition program. This program, starting with a company policy and proceeding under a “Corporate Plan,” set the company on the metric road effective 1 July 1972. Its planning, philosophy, policy, training projections, and experience are presented as a case history in this paper.
Metrication Experience at Caterpillar Tractor Co.
Authors: Strang LR , Schellschmidt VW , Langenstein JG
Published: March 2009

In November 1971, Caterpillar Tractor Co. started to change the measurement system in all its U. S. operations to the International System of Units (SI). This paper gives a brief description of Caterpillar, its products, policies, and worldwide operations to help in understanding the reasons for this decision.
Metrication—How One Small Company Did It
Authors: Fontaine RE
Published: March 2009

Since its founding in 1888, Morgan Construction Company has been a leader in the manufacture of rod and bar mills for rolling both ferrous and non-ferrous products. Although, Morgan's first experience with metrication came in the 1920's, it was not until 1970 that a concentrated effort was made to convert its design and manufacturing operations to the metric system. The decision to “go metric” resulted in part from a desire to accommodate foreign licensees; the major pressure for change, however, came from an increasing foreign market.

In August of 1970, Morgan set up a twenty-man task group, representing a cross section of its drafting talent, to start a pilot program converting an existing design from traditional inch dimensions to metric. The task was not easy. There was no single set of standards for metric design; instead, there was a proliferation of standards. The first step was to catalog existing metric standards, and develop a single interim metric standard for use at Morgan. The conversion processes started concurrently with the development of standards.

After some trial and error, it was determined that the most effective method of converting an existing inch drawing to metric is to: photographically generate an undimensioned copy of the inch drawing; calculate new dimensions in millimeters; round off calculations in accordance with the interim standards; and then add the new dimensions to the photographic copy to make a new drawing. The finished metric drawing is then checked and processed in the same manner as inch drawings. New drawings with no inch drawing equivalent are developed entirely in the metric system.

Manufacturing from metric drawings progressed well; however, there were problems working with machine tools with inch readouts. All new machine tools have been purchased with both inch and metric readouts to simplify the problem. Metric gearing can be cut on existing gear cutting machines, but metric threads required new tools. The inspection department uses instruments with metric readouts.

Continuing problems include the availability of metric components; the lack of standard metric structural shapes and plate thicknesses; a lack of English-language reference books; and the variety of existing metric standards. The people problem remains as a major hurdle. Draftsmen, long accustomed to thinking in inches, have difficulty thinking in millimeters; and, once a draftsman has become adjusted to metric standards, he frequently has difficulty reverting to inch standards.

Overall, Morgan has made many crucial decisions that have led to a relatively smooth transition to both metric design and manufacture. Morgan has not solved all the problems of converting to metrics, but has now produced more than 10 000 metric drawings that have been used to manufacture and install 16 mills in seven countries successfully.
One Electronic Company's Approach to Metrication
Authors: Markstrom PA
Published: March 2009

This paper covers the general environment and criteria leading to IBM's decision to implement SI-Metric into selected new products and processes within the corporation.

Subjects covered are long range planning for the program, organization, tasks, education, and implementation. Examples of activities and phase-in plans will be discussed.
Discussion of ASTM Method for Rating Inclusions
Authors: Donze JJ
Published: March 2009

Since nonmetallic inclusions are always present in steel, it is important to identify and classify the size and type of inclusion. ASTM has set up basic guidelines obtaining samples and rating the inclusion. Under microscopic examination, the size, distribution, number, and type of inclusions are examined and compared to various standard ASTM charts.

The examination and rating of six samples taken in a systematic way as outlined by an ASTM procedure generates the nonmetallic inclusion rating for that heat. There are four ASTM bearing specifications that cover different grades of steel used in the bearing industry: ASTM Specification for High-Carbon-Chromium Ball and Roller-Bearing Steel (A 295-70); ASTM Specification for High Hardenability Bearing Steels (A 485-63); ASTM Specification for Carburizing Steels for Anti-Friction Bearings (A 534-65); and, ASTM Specification for Special Quality Ball and Roller Bearing Steel (A 535-65).

The ASTM method of evaluating bearing steels is commercially oriented to enable the steel producer to consistently evaluate numerous heats of steel.
Assessment of Nonmetallic Inclusion Content and the Relationship to Fatigue Life of One Percent Carbon-Chrome Steels
Authors: Meredith JE , Sewell JF
Published: March 2009

Collaborative work by a steel maker and a bearing tube maker on the effect of nonmetallic inclusions on the fatigue life of bearing steels suggests that, at the high levels of cleanness now normally attainable, traditional methods of inclusion counting are irrelevant and may lead to unjustifiable rejection of perfectly satisfactory casts. Examination of failure mechanisms suggests that other metallurgical factors may have a more significant effect on bearing fatigue life.
Rating of Nonmetallic Inclusions by Image Analysis
Authors: Johansson S
Published: March 2009

Image analysis has proved to be a reliable method for the rating of steel cleanness. One analysis gives information about the average content of oxides and sulfides, the existence of critical inclusions according to size, and by specific field counting information related to the macroscopic fraction of inclusions.
Ultrasonic Rating of Bearing Steel Cleanliness
Authors: Burr WH
Published: March 2009

A testing procedure is described wherein immersion ultrasonic cleanliness ratings obtained for 4 by 4 by 6-in. (100 by 100 by 150 mm) test specimens are used instead of microcleanliness ratings to assess the cleanliness of production heats of alloy steel. Good sensitivity and reproductibility of test results are demonstrated, and correlation with microcleanliness ratings is discussed. The major advantage is more meaningful cleanliness ratings because of the much larger volume of metal represented.
Structural Integrity Assessment of Filament-Wound Components
Authors: Lenoe EM , Neal D
Published: March 2009

This paper summarizes the results of a structural integrity assessment of filament-wound glass-epoxy cylinders and rocket motor cases under conditions of dynamic fracture due to internal pressure loadings of the order of 10-ms duration. Experiments were completed on four types of fiber glass configurations; straight cylinders of various angle ply orientations, tapered cylinders, and two bonded rocket motor case designs were evaluated. A brief review is provided of techniques to assess failure rates, and these elementary reliability techniques are used to establish the relative effects of variability in design pressure and burst pressure capacity. Type II and Type III extreme value and normal distributions are utilized. Polynominal approximations for normal distribution and graphical estimates as well as a transform method are used effectively in determining failure rates for nonnormal functional representation. Furthermore, the merit of several different design concepts, as well as the reliability growth achieved with improved manufacturing techniques, is quantified in terms of the estimated probability of component failure. Failure rates are shown to be more sensitive to design pressure variations than the conventional safety-factor approach. Finally, while the reliability methodology described in the paper is sufficient for preliminary design purposes, failure mode assessment via posttest examination and high-speed photographic observations suggests the necessity for further improvements in composite analysis procedures.
Evaluation of Adhesive-Bonded Joints in Housing Components of Glass Fiber-Reinforced Polyester Laminate
Authors: Masters LW , Reichard TW
Published: March 2009

A series of tests was performed on sandwich panel housing components made with glass fiber-reinforced polyester (FRP) laminates. Specifically, long- and short-term tests were performed to evaluate the adhesive bonds between the FRP laminate facings and cores of the panels. Specimens of two different FRP laminates were analyzed and their bonding characteristics with two different adhesives were studied. The test data show that the bond strength was significantly affected by the laminate formulation, adhesive formulation, adhesive thickness, sustained loading, and temperature.
Vibration Testing as a Nondestructive Test Tool for Composite Materials
Authors: Adams RD , Walton D , Flitcroft JE , Short D
Published: March 2009

Certain failures, such as resin bound shear cracks in fiber-reinforced materials, give rise to little change in ultrasonic attenuation or radiographic transmission but can result in significant reductions in material properties. A vibration technique is being evaluated as a nondestructive test tool under such conditions. The work described forms the first part of this evaluation program and concerns unidirectional carbon and glass fiber reinforced plastic subjected to static and dynamic torsional loading. The results and techniques will eventually be applied to complex composite structures.

In the static torsion test program, ‘good,’ void-free specimens failed at shear stresses of between 52 and 60 MN/m2 (carbon fiber) and between 56 and 62 MN/m2 (glass fiber) in a very brittle manner. The cracks thus generated led to substantial changes in the dynamic (vibration) test data. Specimens containing voids failed at lower shear stresses and less catastrophically.

In torsional fatigue, all failures occurred by the propagation of resin-bound shear cracks at shear stresses below the static strength of the material. The dynamic (vibration) test parameters showed permanent and progressive changes due to the accumulation of fatigue damage. Crack development was observed visually in the glass fiber specimens and broadly related to the changes in the dynamic properties.
Application of a Special X-Ray Nondestructive Testing Technique for Monitoring Damage Zone Growth in Composite Laminates
Authors: Chang FH , Couchman JC , Eisenmann JR , Yee BGW
Published: March 2009

A modified X-ray nondestructive testing technique was used to study matrix cracks parallel to fibers and delaminations between plies in graphite-epoxy composite material. A tetrabromoethane (TBE) opaque additive applied at the source of the damage zones enhanced the flaw image.

Center-slit specimens were fabricated from Modmor II/Narmco 5208 graphite-epoxy laminates with three different ply orientations. Tensile ramp and sawtooth cyclic loadings at different levels were applied to these specimens. Periodic X-ray monitoring was conducted to observe the initiation and growth of cracks and delaminations at the slit tips. The initiation of damage zones appeared as fiber separation in the ±45-deg directions tangent to the semicircular periphery of the cutout tips. As the load level was increased, this fiber separation continued while fiber separation at other locations also appeared.

Delamination first occurred at approximately the same time as fiber separation. The delaminated area was found to surround the most severe fiber separation region and grew in size as the load level was increased.

Limited test results indicated a slow and an accelerated damage growth rate during ramp loading. For cyclic loading the majority of growth occurred on the first load cycle. Subsequent cyclic loading to the same level contributed little additional growth in the majority cases.
Acoustic Emission from Stress Rupture and Fatigue of an Organic Fiber Composite
Authors: Hamstad MA , Chiao TT
Published: March 2009

A series of tests was carried out to determine the scatter in acoustic emission data gathered during stress rupture and fatigue testing of a simple fiber-reinforced epoxy composite. Single-end organic fiber-epoxy strands were monitored for acoustic emission during tension tests to failure, stress rupture tests, and dynamic fatigue tests. During the stress rupture and fatigue tests, the plots of summation of acoustic emission counts versus time were found to resemble metal creep curves in that primary, secondary, and tertiary regions could be distinguished. Because of a significant amount of scatter, only a limited correlation can be made between the slope of the summation of acoustic emission in the steadystate region and the specimen life during stress rupture and fatigue testing. In addition, flawed specimens were easily sorted out during the tension tests. These results indicate that acoustic emission data gathered during composite fatigue and stress rupture testing might be useful for life prediction.
Optimization of the Thermal Shock Resistance of Carbon-Carbon Composites
Authors: Guess TR , Butler BL
Published: March 2009

A three-dimensional rule of mixtures model was developed to calculate the room-temperature thermal and mechanical properties of carbon-carbon composites whose constituents have anisotropic properties. The model was used, along with the properties of different carbon fibers and pyrocarbon matrices, to determine the fiber-matrix combination, constituent volume fractions, and constituent orientations that maximize expected composite thermal shock resistance of heat shields. The results indicate that a composite having a low volume fraction of high-modulus carbon fibers, arranged in a 3D array, and coated with anisotropic, heat-treated pyrocarbon matrix, will have the maximum thermal shock resistance. Confidence in the model was established by good agreement between model predictions and experimental data on actual carbon-carbon composites.
Prediction of Transverse Strength and Scatter in Test Data for Unidirectional Composites
Authors: Greszczuk LB
Published: March 2009

An approximate theory is presented for predicting the transverse tensile strength of composites from the properties of constituents and composite microstructure. The theory takes into account internal triaxial stress concentrations caused by fibers, triaxial stress concentrations caused by voids, and the interaction of stress concentrations from fibers and voids. The theoretically predicted transverse tensile strength is compared with test data for glass-epoxy and graphite-epoxy composites made with various resin systems. To establish the causes for test data scatter, systematic studies are conducted on the influence, on the predicted transverse strength, of fiber content, void content, specific gravity, and resin strength variations within the various groups of test specimens. The results of these studies are used to predict the scatter in transverse strength of composites. These scatter predictions are useful in identifying the major causes and variables which need closer control in order to minimize the scatter in test data and thereby improve the reliability of composites.
A Computational Procedure to Analyze Metal Matrix Laminates with Nonlinear Lamination Residual Strains
Authors: Chamis CC , Sullivan TL
Published: March 2009

An approximate computational procedure is described for the analysis of angleplied laminates with residual nonlinear strains. The procedure consists of a combination of linear composite mechanics and incremental linear laminate theory. The procedure accounts for initial nonlinear strains, unloading, and in-situ matrix orthrotropic nonlinear behavior. The results obtained in applying the procedure to boron-aluminum angleplied laminates show that this is a convenient means to accurately predict the initial tangent properties of angleplied laminates in which the matrix has been strained nonlinearly by the lamination residual stresses. The procedure predicted initial tangent properties results which were in good agreement with measured data obtained from boron-aluminum angleplied laminates.
Measurement of Residual Strains in Boron-Epoxy and Glass-Epoxy Laminates
Authors: Daniel IM , Liber T , Chamis CC
Published: March 2009

Embedded-strain-gage techniques were developed and used for measuring strains in composite angle-ply laminates during curing and thermal cycling. The specimens were 2.54 by 22.9 cm (1 by 9 in.) eight-ply boron-epoxy and S-glass-epoxy [02/ ±45]s laminates. Unidirectional [08] specimens were also used for control purposes. Strain readings were corrected for the purely thermal output of the gages obtained from an instrumented quartz reference specimen. The strains measured during the cooling part of the curing cycle were in agreement with those recorded during subsequent thermal cycling, indicating that residual stresses induced during curing are primarily caused by differential thermal expansions of the various plies. Restraint strains, that is, the difference between unrestrained thermal strains of a given ply and the restrained strains in the laminate, were computed for the 0-deg and 45-deg plies of the angle-ply laminates tested. Residual stresses were obtained from these restraint strains using the anisotropic constitutive relations and taking into account the temperature dependence of stiffnesses and strains.
Compressive Strength of Fiber-Reinforced Composite Materials
Authors: Davis JG
Published: March 2009

Results of an experimental and analytical investigation of the compressive strength of unidirectional boron-epoxy composite material are presented. Observation of fiber coordinates in a boron-epoxy composite indicates that the fibers contain initial curvature. Combined axial compression and torsion tests were conducted on boron-epoxy tubes and it was shown that the shear modulus is a function of axial compressive stress. An analytical model which includes initial curvature in the fibers and permits an estimate of the effect of curvature on compressive strength is proposed. Two modes of failure which may result from the application of axial compressive stress are analyzed—delamination and shear instability. Based on tests and analysis, failure of boron-epoxy under axial compressive load is due to shear instability.
Stress-Rupture Strength and Microstructural Stability of W-Hf-C Wire-Reinforced Superalloy Composites
Authors: Petrasek DW , Signorelli RA
Published: March 2009

W-Hf-C/superalloy composites were found to be potentially useful for turbine blade applications on the basis of stress-rupture strength. The 100- and 1000-h rupture strengths obtained for 70 volume percent fiber composites tested at 1090°C (2000°F) were 420 and 280 MN/m2 (61 000 and 41 000 psi). The investigation indicated that with better quality fibers, composites having 100- and 1000-h rupture strengths of 570 and 370 MN/m2 (82 000 and 54 000 psi) may be obtained. Metallographic studies indicated sufficient fiber-matrix compatibility for long-time applications at 1090°C (2000°F) for 1000 h or more.
Determination of Fracture Strength in Orthotropic Graphite-Epoxy Laminates
Authors: Konish HJ , Cruse TA
Published: March 2009

A fracture test program performed on orthotropic graphite-epoxy laminates is reported. The test data are used to evaluate the effects of specimen size and specimen configuration on the measured value of laminate fracture strength. It is shown that apparent fracture strength is independent of specimen configuration and specimen thickness, but varies significantly with respect to crack length. As crack length increases, however, the apparent fracture strength is found to asymptotically approach a limiting value, taken to be the valid laminate fracture toughness.

The test data are also used to evaluate two analytical models for predicting laminate fracture toughness. The first model links basic ply properties and the fracture toughness of angle-ply laminates, while the second model relates the fracture toughness of an arbitrary orthotropic laminate to the fracture properties of its angle-ply components. Both models show good agreement with the test data.

It is concluded that linear elastic fracture mechanics does provide a meaningful characterization of crack growth in orthotropic composite laminates, if some specified conditions are met. Study of cases which do not meet these conditions is recommended for future work.
Fatigue Crack Propagation Rates in Woven and Nonwoven Fiber Glass Laminates
Authors: Mandell JF
Published: March 2009

The characteristics of fatigue crack propagation are described for fiber glass laminates containing woven fabric, woven roving, chopped fiber mat, and unidirectional ply reinforcement. The mode of crack propagation is shown to be a stepwise, ligament by ligament advance of the crack front. The rate of crack propagation is predicted to vary exponentially with the stress intensity factor by an approximate theory based on the fracture toughness, unnotched fatigue life curve, and microstructural characteristics. Good agreement is demonstrated between theory and experiment for each material. The crack growth rate data are normalized to a single relationship for all woven reinforcements, and to a second relationship for nonwoven reinforcements.
Thermal Conductivity of High-Modulus Carbon Fibers
Authors: Kalnin IL
Published: March 2009

The axial thermal conductivity of high-modulus carbon fibers near room temperature is determined from the measured thermal conductivity of their unidirectional composites and also directly on a dry fiber bundle. A device providing the necessary thermal and electrical connections to the heated fiber bundle is described.

The thermal conductivity of 14 commercial carbon fiber grades ranged from 1.42 W/cm °C for the highest-modulus (GY-70) fiber to 0.03 for the low-modulus (VYB) one. Correlations are given between the thermal and the electrical conductivities and the fiber moduli. Above 0.1 W/cm °C the thermal conductivity increases linearly with the electrical conductivity or the elastic modulus, whereas below that value it becomes nearly independent of modulus, and is accompanied by a sharply decreased electrical conductivity.
Thermoelastic Expansion of Graphite-Epoxy Unidirectional and Angle-Ply Composites
Authors: Wang ASD , Pipes RB , Ahmadi A
Published: March 2009

An experimental investigation of the thermal expansion of a unidirectional fiber-reinforced composite material is described herein. The basic material used in the tests was a prepreg graphite-epoxy tape, designated as Modmor-II, supplied by NARMCO. Unidirectional and angel-ply laminates were made from the prepreg tape and were tested for their linear thermal expansion in the temperature range between 25 and 150 °C (77 and 302 °F). The experimental results compared reasonably well with the predicted values of the thermal expansion coefficients calculated based on several existing linear elastic micromechanics theories and lamination theories.
Working with Borderline Aggregates
Authors: Dolar-Mantuani L
Published: March 2009

Borderline aggregates are those that do not meet all of the requirements for satisfactory aggregate but may be suitable for applications where inadequacies of the aggregate will not have a significant adverse effect on the life or performance of the concrete. The borderline quality is determined usually by standard acceptance tests using generally agreed upon acceptance limits, and by standard and specific tests with specially set acceptance limits.

A thorough knowledge of both the aggregate characteristics and the specific properties needed in the concrete is essential to properly assess a borderline aggregate for any application. Petrographic examinations help to identify the deficiencies. In many applications, when comparing the properties of borderline aggregates with requirements of the job, it may be helpful to consider the strength and durability factors separately.

Methods which help to ensure safe use of borderline aggregates and the principal beneficiation methods which can be used to improve the quality of aggregates are listed and examples are given.
Evaluation of Potential Alkali-Carbonate Reactions
Authors: Emery JJ , Drysdale RG
Published: March 2009

The application of an integrated procedure for evaluating marginal aggregates with potentially deleterious degrees of alkali-carbonate reactivity is described. This evalation couples petrographic examination and laboratory expansion testing with a detailed field inspection of existing structures. Field inspection often indicates other sources of potential problems such as chert zones, shale pop-outs, road salt action, and the influence of high sulfate environments. In addition to providing expansion data, preparation of test prisms may indicate other problems such as poor workability. For the typical portland cements and range of alkali contents used, there was no laboratory evidence of deleterious alkali-carbonate reaction for the aggregates in question. This confirmed the field observations. It is critical that all aspects of performance, including workability and special construction precautions, be considered when examining the economics of using a marginal aggregate source.
Suitability of Shale as a Construction Material
Authors: Reidenouer DR , Geiger EG , Howe RH
Published: March 2009

A study of many shale-like rocks from Pennsylvania was made to develop a material specification which would define shales suitable for use in appropriate types of construction. Specimens of shale were subjected to a wide variety of physical, chemical, and petrographic analyses.

A simple classification of argillaceous rocks shows the nomenclature of shale-like rocks. A two-part test procedure was developed for rapid acceptance or rejection of shales in the field: screen by on-site observation of lamination thickness and weathering characteristics, and make final selections by using both an ethylene glycol soaking test and a modified Washington degradation test. Limiting values of the Washington degradation factor have been selected for specific uses of shale in construction.
Chert-Aggregate Concrete Durability After Antifreeze Treatment
Authors: Lin CH , Walker RD , Payne WW
Published: March 2009

One potential method of aggregate upgrading and analysis of its economic feasibility is illustrated. A low durability predominantly chert aggregate was used in concrete after being vacuum saturated with various liquids including plain water, solutions of water and ethylene-glycol, plain ethylene glycol, and water saturated with calcium chloride. Concrete specimens were fabricated and exposed to alternate cycles of freezing and thawing in water. Concrete with aggregates saturated with 100 percent ethylene-glycol showed a strong increase in durability. The calcium chloride treatment showed no effect. A “ball park” cost comparison showed that aggregate production with ethylene-glycol would cost about 4.5 cents per ton as against 20 cents per ton for normal heavy-media separation treatment.
Gas Turbine Emission Measurement Instrument Calibration
Authors: Dieck RH
Published: March 2009

Fundamental to valid emission measurements is the proper calibration of the measurement instrumentation. This paper addresses the problems associated with instrument calibration and assesses the role of instrument uncertainty in the complete analysis of error. A review of the need for instrument calibration is included, as is a discussion of the basic methodology required, from securing the necessary calibration data to its evaluation in a statistical framework.

Topics necessary for proper instrument calibration and uncertainty assessment included are: proper choice of units, definition of terms, calibration to calibration precision and its variability, calibration curve fitting, calibration curve shifts and their evaluation, errors common to instruments in systems, comparisons to other identical instruments, and evaluation of manufacturers' statements.

In addition, a comparison of typical instrument performance with that required by the Environmental Protection Agency (EPA) is made.

Finally, the need for real-time assessment of instrument precision is discussed, and an example of how it has been achieved at Pratt and Whitney Aircraft is presented.
Qualification of Ambient Methods as Reference Methods
Authors: Clements JB
Published: March 2009

A description is given of a measurement methods qualifications program used by the Environmental Protection Agency (EPA) in its reference methods activities. The first step of the two-step program is an in-depth evaluation of a method for the purpose of critically examining, in a single laboratory, a method to determine its strengths and weaknesses. The second step is an interlaboratory collaborative test of the method whereby the method is placed in the hands of typical users for the purpose of determining important statistics on precision and accuracy. The program for evaluating methodology for ambient nitrogen dioxide in support of EPA's replacement reference method is presented as an example of this process.
Verification of In Situ Source Emission Analyzer Data
Authors: Lord HC
Published: March 2009

The accuracy of analytical measurements is controlled by a variety of factors. One of the most significant is the calibration technique utilized for the interpretation of the instrument output. Others are the presence of interfering species or the presence of random errors due to environmental, instrumental, or operator changes. The calibration of in situ analytical systems poses new requirements for the instrument manufacturer and user. Calibration techniques and verification of their authenticity in providing accurate in situ data are discussed in this paper.
Evaluation of Data Obtained by Reference Methods
Authors: Taylor JK
Published: March 2009

The key role of reference methods for measurement of air pollutants in regulatory matters demands that the data obtained in their use be precise and accurate, but no procedures have been established for evaluating its reliability and validity for the intended use. This paper discusses the general principles of reliable analytical measurements and presents guidelines by which the quality of data obtained by reference methods or other procedures may be evaluated.
Permeation Tube Equilibration Times and Long-Term Stability
Authors: Williams DL
Published: March 2009

The time required to reach permeation rate equilibrium after a temperature change, and the long-term rate stability were investigated for fluorinated ethylene propylene (FEP) and tetrafluoroethylene (TFE) Teflon permeation tubes filled with sulfur dioxide, hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. The effect of repeated temperature changes on the repeatability of permeation rates was determined for permeation tubes filled with ammonia, nitrogen dioxide, and sulfur compounds. A two-stage process to equilibrium was observed for tubes made of FEP Teflon. Permeation through TFE Teflon requires one fifth the time to reach equilibrium and does not exhibit the same two-stage equilibration process. Long-term stability was good for both FEP and TFE membranes. Permeation rates were reproducible after repeated temperature cycles.
Application of Gas Phase Titration in the Calibration of Nitric Oxide, Nitrogen Dioxide, and Ozone Analyzers
Authors: Rehme KA
Published: March 2009

A detailed procedural description of a technique developed and applied within the U. S. Environmental Protection Agency for the dynamic calibration of ambient air monitors for nitric oxide, nitrogen dioxide, and ozone is presented. A gas phase titration technique, utilizing the rapid gas phase reaction between nitric oxide and ozone, is used in such a manner that, with the concentration of one of the three gases known, the concentrations of the other two can be determined. A working cylinder of nitric oxide in nitrogen is standardized using one of three possible primary standards. Cylinder nitric oxide is then used as a secondary standard for routine calibrations. Ozone is added to excess nitric oxide in a dynamic calibration system, and a calibrated chemiluminescence nitric oxide analyzer is used as an indicator of changes in concentration. The decrease observed on the calibrated nitric oxide analyzer upon addition of ozone is equivalent to the concentration of nitric oxide consumed, the concentration of ozone added, and the nitrogen dioxide concentration produced. Once the concentration of the three gases has been determined, rapid and routine calibrations of ozone, nitric oxide, and nitrogen dioxide monitors may be performed at a common manifold. Experimental results showing the interrelationships that exist among the three gases are also presented.
Stability of Nitric Oxide Calibration Gas Mixtures in Compressed Gas Cylinders
Authors: Lee WG , Paine JA
Published: March 2009

A preliminary experimental study has been made to determine the factor affecting the stability of reactive calibrations gas mixtures. The model system selected for study was nitric oxide (NO), at various concentrations in nitrogen, argon, and helium as the inert diluting gas. Quantitative data have been obtained which indicate that cylinder conditioning and concentration of the mixture are major factors affecting shelf life. Total mixture pressure and temperature cycling appear to play a minor role in stability, except at low parts-per-million concentrations. No major differences were found in comparing mixture stability in stainless versus chrome-molybdenum steel.

It was observed that the chemiluminescence detecting principle for determining NO appears sensitive to the inert matrix gas used in mixtures. The measured concentration of NO in the mixture varies with the molecular weight of the inert gas.
Role of The National Bureau of Standards in Calibration Problems Associated with Air Pollution Measurements
Authors: Hughes EE
Published: March 2009

The National Bureau of Standards (NBS) produces a limited number of Standard Reference Materials (SRM's) for air pollution and related analyses. The effort involved in the preparation and certification of these standards precludes production in large quantities or of great variety. The requirements for accuracy and stability of samples necessitate a considerable research effort prior to production of the actual SRM's. The decision as to what gas mixtures will be prepared as SRM's is based primarily on a demonstrated need modified by anticipated demand and by other obligations of the SRM program. The demand for these SRM's is increasing, and maintaining stocks of current SRM's must compete with the necessary research prior to issuance of new SRM's.

Comparisons are presented of independent analyses of a number of SRM's currently in use for measurement of automotive emissions.
A Calibration Procedural System and Facility for Gas Turbine Engine Exhaust Emission Analysis
Authors: Elwood JH
Published: March 2009

This paper is directed toward those individuals and organizations who, in the process of being regulated, are, or have been, required to develop their own standard reference materials, to establish the analytical procedures necessary to develop and maintain these materials, and to evolve a calibration methodology for using these standard materials in day-to-day operations, as well as for compliance testing.

In the Federal Register, (Vol. 38, No. 136, Part II, 17 July 1973) the Environmental Protection Agency (EPA) promulgated “Emissions Standards and Test Procedures for Aircraft.” Maximum allowable emission levels were established for smoke, carbon monoxide, hydrocarbons, and oxides of nitrogen; and, in addition, criteria were established for the measurement of these constituents. Requirements were also set for the measurement of carbon dioxide to be used in determining the representativeness of the sample. At that time, only a few selected standard reference materials, developed for the automotive industry, were available. These were three concentrations of carbon dioxide in nitrogen and five concentrations of propane in air, all certified to ±1 percent over a 95 percent confidence interval. The EPA required that all calibration gases would be known to ±2 percent without specification of the confidence interval. There was no suggestion as to a source of these relatively high accuracy gases, how to guarantee the accuracy of assay, or how they were to be maintained, monitored, and used. Generally poor experience with gas vendor's abilities to consistently supply gases within 2 percent of the certified analysis, and the demonstrated instability of some mixtures in the cylinder led, in part, to the decision to develop a standard reference materials laboratory in support of our emissions measurement technology programs. This standards laboratory was charged with :

1. Providing a bank of standard reference gases for use in all emissions measurement technology programs at Pratt and Whitney Aircraft.

2. Where analytical procedures for making high accuracy determinations of gas concentrations were lacking, to develop this capability.

3. Develop procedural systems necessary to make this reference bank of standards available for day-to-day instrumentation calibration, and 30-day detailed calibrations as required by the EPA.

4. Determine, insofar as practicable, our ability to perform analyses and assign concentration levels in comparison with the rest of the industry.

5. As National Bureau of Standards standard reference materials become available, to adopt these standards and phase them into our program.

These goals have been met in essentially all respects. In addition, it has been determined that the practically achievable precision and accuracy of measurement is significantly different from that implied by the EPA, and it is highly unlikely that their high accuracy requirements can be met.
Problems with Zero Gases for Ultra-Low Level Measurements of Air Pollutants
Authors: Scott WE , Marrin JT
Published: March 2009

The replacement of wet-chemical methods of measuring air pollutants by more sophisticated instruments has introduced a number of new problems. Most of the new analytical instruments do not give absolute results. Instead, their measurements are relative to a reference standard containing a “known” concentration of the pollutant of interest and to a “zero” standard containing neither the pollutant of interest nor interfering components. As the attempt is made to measure pollutants at very low levels, it becomes more difficult not only to produce reference standards, but also equally difficult to establish the zero level.

The specific requirements for ultra-pure zero gases, including carrier gases employed in Chromatographic measurements, are illustrated for many instruments in use today. Problems in the handling of zero gases are discussed. Results of tests demonstrate the ease of contamination of zero gases by regulators, sample lines, syringes, etc. Solutions to many of these handling problems are presented.
Electrochemical Generation of Pollutant Standards
Authors: Harman JN
Published: March 2009

Six common ambient air pollutant species (ozone, nitric oxide, chlorine, carbon monoxide, sulfur dioxide, and hydrogen sulflde) have been electrolytically generated at the parts-per-billion to parts-per-million level in a scrubbed ambient air carrier. Theoretical background and practical aspects of this technique are discussed, and the difference in pollutant output to that expected theoretically is reviewed. Under the conditions of the work reported, the desired theoretical output was not achieved. As a result, this technique does not appear feasible as a primary technique for the production of these species. However, the approach may serve as a convenient, low-cost means to produce secondary or working standards for the calibration of ambient level air pollution analyzers.
Redundant Calibration of Nitric Oxide, Carbon Monoxide, Nitrogen Dioxide, and Ozone Air Pollution Monitors by Chemical and Gravimetric Techniques
Authors: Stedman DH , Kok G , Delumyea R , Alvord HH
Published: March 2009

Calibrated nitric oxide (NO) sources are described using ammonia and nitromethane permeation followed by pyrolysis. A field carbon monoxide calibrator based on nickel carbonyl as the liquid fill is discussed. Two techniques for intercalibrating chemiluminescent NO and ozone (O3) meters using the photolysis of nitrogen dioxide (NO2) are demonstrated, together with the feasability of a continuous check on NO, NO2, and O3 meters in ambient air, based on a photostationary state measurement.
Present Approaches to Toxicity Testing—A Perspective
Authors: Mount DI
Published: March 2009

It is a real pleasure to see that so many industrial people are actively working in aquatic toxicology. Formerly, papers were presented mostly by participants from public agencies since they were the ones doing aquatic testing at that time. Now many people utilize such tests to assess hazards to aquatic life from many forms of pollutants.
The Importance of Sequential Assessment in Test Programs for Estimating Hazard to Aquatic Life
Authors: Duthie JR
Published: March 2009

The qualification process for a new chemical should include not only appropriate toxicity testing but supportive evaluations which allow an assessment of potential risk to aquatic life. Since materials differ not only in toxicological effect but also in other properties that can affect their ecological impact, each material should be considered individually, and any tendency to apply a rigid standard test program to all should be resisted. Guidelines are provided to develop testing programs which will provide a sound basis for hazard assessment without squandering limited scientific resources.

Review and assessment of data on a sequential basis are necessary to focus effort on the most appropriate kinds of tests. Based on expected usage and disposal patterns, it is important to estimate the maximum concentrations that are likely to occur in the environment and their critical locations. When chemical or biological tests have indicated that a material will not be persistent, the use of shorter term toxicity tests on sensitive life stages may be substituted for total life-cycle tests. Similarly, consideration of chemical and physical properties may provide guidance on the need or priority for bioconcentration testing.

Review points are identified where a decision to either abandon or utilize a test material should be considered rather than continuing a fixed pattern of testing that merely postpones a difficult judgment.
A New Capacitor Fluid—A Case Study in Product Stewardship
Authors: Branson DR
Published: March 2009

Product stewardship is a commitment to exercising responsible care during the manufacturing, use, and ultimate disposal of chemical products. An important part of product stewardship is the generation of an adequate data base to assess the potential hazards of a new product. A new capacitor fluid (Dow's XFS-4169L) is a working example of product stewardship. Electrically, the fluid has been found to perform as well as or better than capacitor-grade polychlorinated biphenyl (PCB) in capacitors. Assessment of its health and environmental acceptability was based on the composite interpretation of movement, stability, bioconcentration, and toxicity data.

The use pattern, sediment binding, and recommended disposal suggest that only small amounts of the new capacitor fluid will enter the aquatic environment. The routes for leaving the aquatic environment—biodegradation and volatilization—allow only very low concentrations of the capacitor fluid to remain in water. The bioconcentration potential of the fluid is low enough so that residue levels in fish are not critical to the health of the fish or animal consumers, and its toxicity to aquatic organisms is similar to that of a large group of commodity chemicals and less than PCB's.
Mysidopsis bahia: An Estuarine Species Suitable for Life-Cycle Toxicity Tests to Determine the Effects of a Pollutant
Authors: Nimmo DR , Bahner LH , Rigby RA , Sheppard JM , Wilson AJ
Published: March 2009

This study documents the successful use of a mysid, Mysidopsis bahia, for life-cycle toxicity tests. These tests were conducted to determine acute and chronic toxicities of metal (cadmium) and pesticide (Kepone). Delay in the formation of mysid brood pouches and release of young were noted in low concentrations ⩽6.4μg cadmium/litre. Fewer young produced per female and decreased growth were other indicators of effects of Kepone.
Bioassays with a Natural Assemblage of Benthic Macroinvertebrates
Authors: Burks SL , Wilhm JL
Published: March 2009

A new bioassay method for determining the effects of environmental contaminants on populations of benthic macroinvertebrates is described. Colonized Hester-Dendy samplers were transported from a natural stream to artificial streams and exposed to industrial wastewater. Species diversity, number of taxa, and density of the aquatic organisms were measured before and after selected time intervals of exposure. A 30 and a 32-day continuous-flow exposure test with the benthic macroinvertebrates showed that activated sludge treated petroleum refinery wastewater caused a greater decrease in species diversity than the sequential activated sludge-dual media-activated carbon treated effluent. The effect upon number of taxa and mean density of individuals was even greater.

This procedure permitted exposure of several species of aquatic invertebrates to the test solution and thus measured the effect upon pollution-sensitive and tolerant organisms.
Current Bioconcentration Test Methods and Theory
Authors: Hamelink JL
Published: March 2009

Practical and theoretical solutions to the quantitation of chemical accumulation by aquatic animals are evaluated. Laboratory studies presently rely on continuous exposure for extended periods of time to simulate field conditions. Application of the principles of pharmacokinetics permit laboratory results to be compared and indicate that mathematical models can be derived to predict contaminant accumulation under natural conditions adequately. Additional laboratory studies with large-sized and growing fish are identified as future research needs.