NASA Technical Memorandum 108813

Director's Discretionary Fund

Report for FY 1993

Ames Research Center, Moffett Field, California

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CONTENTS

Introduction .................................................................................................................................................................

Laboratory Investigation of the Growth, Structure, and Apparent Phase Equilibria of Polar

Stratospheric Clouds ..................................................................................................................................................

David F. Blake

The Preservation of Organic Matter in Hot Spring Deposits: Developing Search Strategies for

a Fossil Record on Mars ..............................................................................................................................................

David F. Blake and Jack Farmer

Human Exploration Demonstration Project (HEDP) .............................................................................................

Edward Chevers and David Korsmeyer

Development of Fiber-Optic Acoustic Sensors for Wind Tunnel Applications ..................................................

Young C. Cho and Paul T. Soderman

A Prototype Infrared Gas Analyzer for Characterizing Plant Growth During Space Flight ..........................

James Connolly

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Origins of Planetary Systems: Observations and Analysis .................................................................................

Kent Cullers and Laurance Doyle

Monitoring Global Change During the Last 10,000 Years ....................................................................................

Hector L. D'Antoni

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Schmidt-Cassegrain Long-Range Laser Velocimeter ...................................... .....................................................

Stephen E. Dunagan

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Investigation of the Scales of Turbulence in Hypersonic Rarefied Flow ...........................................................

William J. Feiereisen, Donald Baganoff, and Sanjiva Lele

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Analytical and Experimental Studies of Rotorcraft Vertical Climb Performance ..............................................

Fort F. Felker and Robert M. McKillip

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Continuous-Flow Apparatus for Studies of Gas- and Liquid-Phase Adsorption Dynamics .........................

John E. Finn and Sanford S. Davis

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Development of Modal Filtering Techniques for Online Estimation of Structural

Vibration Parameters .................................................................................................................................................

Lawrence C. Freudinger

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Computational Modeling of Femtosecond All-Optical Switches Directly from

Maxwell's Equations ...................................................................................................................................................

Peter M. Goorjian and Allen Taflove

Tension and Compression Effects of Cell Behavior .............................................................................................

Rosalind A. Grymes and Christine Sawyer

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TheDeuteriumAbundanceintheInterstellarMedium......................................................................................

Michael R. Haas and Alexander G. G. M. Tielens

Determination of Polar Stratospheric Cloud Onset Over Antarctica Using Cloud Top

Temperature Retrievals from the NOAA Advanced Very High Resolution Radiometer

(AVHRR) Satellite Imagery ......................................................................................................................................

Steve Hipskind, Kathy Pagan, Steve Gaines, Oswaldo Garcia, and Patricia Foschi

Real-Time Automated Diagnosis System for the Ames Research Animal Holding Facility ..........................

David L. Iverson and S tephanie Herrin

Stratospheric Aerosol Particulates: Simulation of Their Morphology, Physical

Properties, and Chemistry ........................................................................................................................................

Richard L. laffe

The Use of Molecular Fossils for the Interpretation of Paleoenvironments .....................................................

Linda L. Jahnke

Flight Measured Wall Pressure Fluctuations Beneath Swept Shock/Boundary-Layer

Interactions .................................................................................................................................................................

Steven A. Johnson

Pyrosensors for the Detection of Chemical Compounds in Planetary Environments ....................................

Dan Kojiro and Thomas C. Shen

Practical Evaluation of a New Method to Reduce Helicopter Rotor Hub Loads ............................................

Sesi Kottapalli

Stanford-NASA Ames Cooperative Program in Global Change .......................................................................

James G. Lawless, Philip B. Russell, and Gary Ernst

The Study of Ozone Depletion Chemistry Using Ab Initio Quantum Mechanical Methods ........................

Timothy J. Lee

Surface Shear Stress Measurement Using Liquid Crystal Polymers ..................................................................

B. G. McLachlan, J. H. Bell, M. L. B randes, and M. Gouterman

Investigations of Supersonic Combustion Using Unique NASA Ames Facilities ...........................................

Gene P. Menees, Jean-Luc Cambier, and Henry G. Adelman

Mixing, Combustion, and Thrust Enhancement by a Pulsed Detonation Wave Augmentor ........................

Gene P. Menees, Jean-Luc Cambier, and Henry G. Adelman

Ablating Surface Heat Transfer Estimation for Flight Application ...................................................................

Greg Noffz and Mike Bowman

Crew Decision Making in Aerospace Environments: A Taxonomy of Decision Structures ..........................

Judith Orasanu

Analysis of Arc-Jet Wind Tunnel Vacuum Ultraviolet (VUV) Experiment ......................................................

Chul Park and Dikran S. Babikian

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A Miniature, Lightweight Ozone Analyzer for Use on Unmanned Stratospheric Research

Aircraft ...........................................................................................................................................................................

Richard Pearson, Jr.

Development of a Polarimeter for Astrophysical Applications in the Midinfrared .........................................

Yvonne Pendleton, Lynne Deutsch, and Thomas Roellig

Three-Dimensional (3-D) Disturbances Generated by Suction Holes for Laminar

Flow Control (LFC) .....................................................................................................................................................

Daniel C. Reda and Jonathan H. Watmuff

An Ultralow-Temperature Thin-Film Thermometer .............................................................................................

Pat Roach

Early Warning Blackout Sensor for Pilots and Astronauts .................................................................................

S. A. Rositano, Alan Hargens, and Malcolm Cohen

The Infrared Spectra of Microsamples of Cosmic Interest: Diamonds, Silicon Carbide,

Interplanetary Dust Particles, and Organic Residues ............................................................................................

Scott A. Sandford

Development of a Direct Measurement Transducer for the Oil Wedge Skin-Friction Technique ................

H. Lee Seegmiller

Utility of the Experimental Electro-Optical Camera (SPEC-T) for Assessment of

Insect/Drought Related Forest Mortality ..............................................................................................................

Gary A. Shelton, Vincent G. Ambrosia, and James McKean

A Neural Learning Algorithm for Touch Based Control of Mechanical Manipulation ..................................

Jay Steele

Development of a New System for Canopy Architecture Remote Sensing ......................................................

V. C. Vanderbilt, A. W. Sarto, and B. J. Van Zeghbroeck

Optimization of Spatial Auditory Displays for Multiple Communication Channel

Intelligibility ...............................................................................................................................................................

Elizabeth M. Wenzel and Durand R. Begault

Musculoskeletal Loading or Unloading with Differential Pressure ..................................................................

Robert Whalen, Gregory Breit, and Douglas Schwandt

Aerogel Advanced Material Development ............................................................................................................

Susan White

Effects of Low Energy Impact of Atomic Oxygen and Nitrogen on Advanced Materials .............................

Susan White, Joan Pallix, and Les Barnes

Application of Digital Signal Processing (DSP) to Near Real-Time Compensation of

Attenuated Acoustical and Unsteady Pressure Measurements .........................................................................

Stephen A. Whitmore

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Technology Development for Selective Recovery of Urea from Urine and Its Subsequent

Decomposition to Ammonia with Application in the Controlled Ecological Life Support

Systems (CELSS) ........................................................................................................................................................

Richard Wisniewski

MIR Study of Disks Around Young Stellar Objects .............................................................................................

Fred Witteborn and Harold M. Butner

Predicting Lyme Disease Risk: A Remote Sensing Model Based on Landscape Epidemiology ..................

Byron L. Wood, James G. Lawless, Louisa R. Beck, Sheri W. Dister, and Durland Fish

Appendix ....................................................................................................................................................................

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INTRODUCTION

The Director's Discretionary Fund (DDF) at Ames Research Center was established to fund innovative, high-risk

projects in basic research that are essential to our future programs but otherwise would be difficult to initiate.

Summaries of individual projects within this program are compiled and issued by Ames each year as a NASA

Technical Memorandum.

These summaries cover 48 projects (both final and ongoing) in Fiscal Year 1993.

The contents are listed alphabetically according to the last name of the primary investigator. Following the

narrative reports, an appendix contains a brief description with the financial distribution and status of each of the

projects.

Any questions can be addressed to an investigator directly.

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Laboratory Investigation of the Growth, Structure, and

Apparent Phase Equilibria of Polar Stratospheric Clouds

Investigator(s)

David F. Blake, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The chlorofluorocarbon (CFC)-induced depletion of

ozone in the polar stratosphere is known to involve

heterogeneous chemical reactions on polar stratospheric cloud particles (Solomon, 1986; Tolbert et al.,

1987; Molina et al., 1987). The purpose of this investigation is to identify the phases that exist within polar

stratospheric cloud (PSC) ice particles. We will do this

by growing analog PSC ices under the same conditions

as exist in the polar stratosphere and studying their

structure. We hope that the results will help to clarify

important issues such as the reason for the expansion

of the Antarctic ozone hole, the likelihood of an Arctic

ozone hole, or the possibility that observed ozone

depletions above the midlatitudes will persist or

become widespread.

Progress and results

Funding was only made available for this project in

May of 1993 and some of the equipment necessary to

pursue the research has not yet been received. A

quadrupole mass spectrometer for analyzing gases is

on order and should arrive by October 15. A gas mixing and gas inlet rack has been designed, built by the

glass shop, and installed. A room was cleared and set

up for the apparatus, and a surplus carbon evaporator

was modified for use as a pumping station. A sideentry goniometer from a surplus electron microscope

was modified to fit into the vacuum chamber of the

carbon coater. A cryotransfer stage from the electron

microscope can now be interfaced into the carbon

coater and used as a cold substrate for depositing ices.

Significance of the results: None so far

Publications resulting from study

Molina, M. J.; Tso, T.; Molina, L. T.; and Wang, F. C. Y.:

Antarctic Stratospheric Chemistry of Chlorine

Nitrate, Hydrogen Chloride, and Ice: Release of

Active Chlorine. Science, vol. 238, 1987,

pp. 1253-1257.

Solomon, S.; Garcia, R. R.; Rowland, F. S.; and

Wuebbles, D. J.: On the Depletion of Antarctic

Ozone. Nature, vol. 321, 1986, pp. 755-758.

Tolbert, M. A.; Rossi, Michel J.; Malhotra, R.; and

Golden, D. M.: Reaction of Chlorine Nitrate with

Hydrogen Chloride and Water at Antarctic

Stratospheric Temperatures. Science, vol. 238,

1987, pp. 1258-1260.

Key words

Polar stratospheric clouds, Ozone, Nitric acid hydrate
The Preservation of Organic Matter in Hot Spring Deposits:

Developing Search Strategies for a Fossil Record on Mars

Investigator(s)

David F. Blake, Ames Research Center,

Moffett Field, CA 94035-1000

Jack Farmer, SETI Institute,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

During an early wet and warm climatic period not

unlike that of the Archean Earth, life may have originated and flourished on Mars, only to become extinct

as the atmosphere and climate evolved to its present

state. We know that Earth's fossil record extends back

to about 3.5 billion years. It is not unreasonable that,

should life have originated on Mars, a fossil record

would exist there as well. In recent years, strategies for

exploring Mars have been broadened to address the

problem of detecting a fossil record on Mars.

The very best fossil preservation of microbiotas on

Earth occurs when organisms are encased in microcrystalline silica immediately following burial. Almost

all of the classic Precambrian microbiotas were

preserved in this manner. Where might we search on

Mars for silica deposits capable of preserving fossils?

Recent work indicates that many of the channel networks observed on Mars emanate from point sources

associated with impact craters or volcanic terrains

where thermal activity is strongly suspected. Therefore, thermally driven spring systems were probably

both common and widespread during the early history

of Mars.

This study has as its objective the identification of

biogenic vs. abiogenic fabrics within modem, nearrecent and ancient hot spring sinter deposits on the

Earth. We are using state-of-the-art analytical electron

microscopy to establish criteria for the unequivocal

identification, on a microscale, of relict biogenic and

abiogenic materials and fabrics. These criteria will be

used to develop a search strategy for future robotic

and human exploration of Mars and to further understand the origin and radiation of early life on the

Earth.

Progress and results

All of the modem, near-recent and ancient hot spring

sinter samples have been collected and curated. We

have completed some reconnaisance work involving

the sample preparation techniques using an offsite

argon ion-beam thinner. The request for our own ionthinner, which is essential for the sample preparation

procedure, has been in the procurement process since

January. The RFP for the procurement has just been

released and we anticipate that the equipment will be

in place by December. We will have a new NRC fellow

in our group starting in January who will undertake

major portions of this work.

Significance of the results: None so far

Publications resulting from study: None so far

Key words

Mars exobiology, Hot spring sinter, Silicification
Human Exploration Demonstration Project (HEDP)

Investigator(s)

Edward Chevers and David Korsmeyer,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Marc Cohen, Val Mahaffey, Robert Trent,

Yvonne Clearwater, Cynthia Null, Ed Force,

Gerry Mulenburg, Tom Wynn, Rafael Villegas,

and Bob Mah, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The Human Exploration Development Project (HEDP)

is a multidivision task that addresses the advanced

technology requirements necessary to implement an

integrated working and living environment for a planetary surface habitat. The HEDP project began in the

fall of 1991 and will continue through the summer of

1994. The integrated environment will consist of life

support systems, physiological and psychological

monitoring of the flight crew, a virtual environment

workstation, centralized data acquisition, and habitat

systems health monitoring. There will be several

robotic systems external to the habitat performing

activities to provide representative work loads for the

human subjects.

Four basic goals for the HEDP have been

established:

1. Enhance the technology development and

evaluation process through synergistic cooperation of

multiple Ames divisions.

Z Provide a simulator for evaluation of technology in an integrated system setting.

3. Create a realistic environment for introduction

of new technology.

4. Identify promising technology concepts to

programmatic Centers for new and existing NASA

projects.

Scope

The HEDP consists of a working environment contained in a living environment. The living environment will be housed in the Controlled Environment

Research Chamber (CERC), and the working environment will be remotely operated to the simulated planetary landscape. The two environments are coupled

through an underlying data network that includes a

common set of services and provides a medium for

overall system integration. Many of these services utilize artificial intelligence technologies to maximize

autonomy and minimize crew work loads. The living

environment has both life support and life monitoring

subsystems. The working environment includes standard and virtual reality workstations. External to the

habitat will be robotic devices used as crew work

loads and targets for workstation commands. These

devices are not intended for development of robots,

per se, but to create realistic operational scenarios

equivalent to those anticipated on the lunar surface

and to develop the robotic controls systems and

technologies required.

Status

As of August 1993, the HEDP has finished phase I and

is finishing phase II. The second phase has focused on

the implementation and initial integration of the project's component technologies. Phase III, the physical

installation of the final testbed, will begin in October

1993. Phase IV, the system integration and checkout

phase, will begin in January 1994. The demonstration

phase of the project will begin in April 1994.

Publications

Clearwater, Y. A.: NASA Lunar Surface Habitat and

Remote Exploration Demonstration Project. SAE

Paper no. 921194, SAE 22nd International Conference on Environmental Systems, Seattle, Wash.,

July 13-16, 1992.

Chevers, E. S.; and Korsmeyer, D. J.: The Development

of the Human Exploration Demonstration Project

(HEDP), A Planetary Systems Testbed. AAA

Paper 93-0558, AIAA 31st Aerospace Sciences

Meeting, Reno, Nev., Jan. 11-14,1993.

Rosen, R.; and Korsmeyer, D. J.: The Implementation

of the Human Exploration Demonstration Project

(HEDP), A Systems Technology Testbed. Paper no.

IAF-93-U.1.538, 44th Congress of the International

Astronautical Federation, Graz, Austria, Oct. 16-22,

1993.

Key words

Planetary habitat, Integrated testbed, Simulated

habitat
Development of Fiber-Optic Acoustic Sensors for Wind

Tunnel Applications

Investigator(s)

Young C. Cho and Paul T. Soderman,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

M. G. Irizarry, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Acoustic measurements in wind ttmnels are subject to

certain interference noise effects that are not found in

anechoic chambers. Such effects include wind noise,

flow-sensor interaction noise, flow induced sensor

vibration, deflection of acoustic waves by sensor

induced boundary layers, reflections from sensor support components, and noise due to temperature fluctuation. Currently existing acoustic sensor techniques

are not adequate to cope with these problems. The

objective of this study is to develop new advanced

acoustic sensors to eliminate or minimize these interference restrictions. Fiber-optic interferometric sensor

technology, which has almost matured in underwater

acoustics, is adapted here to develop new sensor

techniques for aeroacoustic measurements but with

new sensor head designs. This technology utilizes the

property that the light wave propagating through

optical fiber undergoes phase modulation when the

fiber is exposed to external fields. The phase modulation is then interferometrically retrieved and processed

to determine the external fields. This technology offers

a number of advantages: high sensitivity, wide

dynamic range, compact sensor package, fight weight,

geometric versatility, superb telemetry capability, high

temperature tolerance, and immunity to electromagnetic interferences.

Progress and results

NASA's first fiber-optic microphone was developed

and fabricated in a breadboard form. Unlike in

underwater acoustics applications, no acoustically

compliant mandrel was used, but polymeric jackets

were used instead as fiber coatings to enhance the

acoustic sensitivity. Preliminary tests of this sensor

were performed in an anechoic chamber. The test

results show that (1) the acoustic sensitivity exceeds

estimation by 60 dB, (2) the noise floor is in the range

of -4 dB to 10 dB in reference to 20 micro Pascal, which

is far below the values required for wind tunnel tests,

and (3) the frequency response function is stable but

requires further efforts including more elaborate tests

and improved sensor head designs.

Significance of the results

The fiber-optic interferometric sensor was developed

and tested for the first time ever for aeroacousfic measurements. The test results demonstrated successflflly

its feasibility as an aeroacoustic sensor. The results

enhance the potential of this sensor technique as a

powerful instrument to solve complex acoustic measurement problems in wind tunnels that cannot be

overcome with the conventional transducer techniques. Furthermore, this technology can easily be

applied to studies of pressure fluctuation associated

with high speed research and parametric studies of

transition as well as other acoustics related research.

Publications resulting from study

1. Cho, Young C.: Fiber-optic Interferometric

Acoustic Sensors for Wind Tunnel

Applications. SPIE Proc., vol. 1795, 1992,

pp. 16-27.

Cho, Young C.; and Soderman, Paul T.: Fiber-optic

Interferometric Sensors for Measurements of

Pressure Fluctuations: Experimental

Evaluation. AIAA Paper 93-0738, 31st

Aerospace Sciences Meeting, Reno, Nev.,

January 11-14,1993.

Key words

Fiber-optic interferometric sensors, Aeroacoustic

measurements, Wind tunnel applications
A Prototype Infrared Gas Analyzer for Characterizing Plant

Growth During Space Flight

Investigator

James Connolly, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Raman Sargis and David Bubenheim,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Accurate and reliable measurement of CO2 and

water vapor is critical for characterizing photosynthesis and transpiration of green plants in space. All

food production, air revitalization and water purification functions of plants depend on proper function

of photosynthesis and transpiration. Current CO2

analysis technologies used in ground-based laboratories have several characteristics that would

severely restrict and limit their reliable and safe use

in space flight. The analyzer design proposed here

would utilize alternative component technologies

and the operation approach to address each of the

limitations and safety problems present in current

instrumentation.

Typical portable CO2 gas analyzers operate

based on the infrared radiation absorption of CO2

gas. As the gas concentration inside the "gas cell"

increases, the amount of radiation from the source

reaching the sensor diminishes. The measured radiation power is then normalized against a predetermined peak radiation to produce a measurement of

the CO2 gas concentration. The infrared gas analysis

method is advantageous over other methods, especially in space because it does not require the use of

chemicals to measure gas concentrations as most

alternate methods do. However the use of existing

infrared gas analysis instruments for high accuracy

CO2 measurements over long periods of time

requires regular calibrations, typically daily, and

consideration of environmental conditions surrounding the analyzer.

Progress and results

The gas analyzer components requiring improvements were divided into two groups. Within these

groups potential solutions were investigated.

Alternative radiation sources

Two sources were investigated to improve the

infrared radiation characteristics.

1. Infrared laser: Miniature laser diodes operating at about 250 K have been investigated. Their

small size and relatively high operating temperature

makes them ideal candidates for use in gas analyzers. The laser beam's energy density is concentrated

within a narrow bandwidth where CO2 gas absorption lines exist. The wavelength of the laser may be

tuned to that of a singular gas absorption line. This

scheme may also be used to calibrate the instrument

by tuning the laser into regions where gas absorption lines do not exist or are extremely weak.

Currently the necessary technology to develop

infrared laser diodes has emerged. However, these

units do not exist because of the high cost of development and lack of commercial interest. Also, laser

manufacturers lack the necessary laser characteristic

requirements to develop the proper laser for gas

analysis.

To encourage the development of the infrared

laser diode, efforts where placed to initiate transfer

of technology. The goal is to use commercial funds

in exchange for marketable technology developed by

NASA. To accomplish our goal, a Joint Sponsored

Research Program (JSRP) has been initiated. The

JSRP is currently being managed by the American

Technology Institute (ATI). ATI is responsible for

analyzing the industry and assisting with the transfer technology to commercial companies in exchange

for development funds. A JSRP proposal has been

completed and will be released to selected companies by ATI.

Once the funds are available, the success of the

development would depend on accuracy of

requirements and the manufacturer's ability to

design to requirements. Therefore the characteristics

of the laser were studied using computer simulation

as well as "simulated" laboratory experiments. Certain absorption bands in the 2 ktm and 4 ktm regions

were analyzed in detail for various path lengths and

environmental conditions. Simulation results indicate that the bands in the 2 ktm region will not provide the desired I ppm resolution. This task will be

especially difficult at high gas concentrations

(10,000 ppm). The absorption bands in the 4 ktm

region can provide the desired resolution if the laser

beam can maintain adequate power and low noise
characteristics. However,sincethelaserdiodesare

notcurrentlyavailable,thesetechniqueswereused

toestimatetheworstcasescenariounderwhicha

laserdiodemaybeusedinagasanalyzer.

In additionto thestudyontheoperatingwavelength,experimentswereconductedtoestimatethe

minimumlaserpower.If theIRradiationpoweris

lowerthanathresholdlimit,thenthegasmeasurement,especiallyatthehigherconcentrations, will be

inaccurate.If thelaserpowerisinadequatetheradiationwill immerseinbackgroundnoisebeyond

recognition.Testresultsindicatethataminimumof

200_twattofIRradiationpowerisrequiredtoallow

analyzerdevelopment.Themeasurementswere

basedon4.1_tmCO2absorptionbandsusinga

16-cmpathlength.

Thepreliminaryresultsoftheseeffortshave

beendiscussedwithleadinglasermanufacturersto

establishfeasibility.Theresultsoftechnicalmeetings

withoneprivatecompanyfollowedbytheirinhousestudiesindicatedthatdevelopment ofboth

the2_tmand4_tmlaserdiodesiswithintheirtechnicalability.Theestimatedcostofdevelopment is

$100,000.

2. Gas-filled flash bulb: Unlike the laser, a flash

bulb is a wide band radiation source. The hypothesis

is that by pulsing an IR radiation source the

radiation of different wavelength will have distinct

signal characteristics.

The IR radiation of the flash bulb was studied

using a breadboard gas analyzer that was constructed to allow the study of various radiation

sources. Also computer codes were written to simulate the typical output of a black body radiation

source. The results overwhelmingly supported the

hypothesis. Figure I exhibits a hypothetical black

body source whose temperaturehas increased from

room temperature to 5,000 K and then decreased to

room temperature in a half-sinusoid shape. The

X-axis represents wavelengths from I _tm to 5 _tm

and the Y-axis is the temperature range from 300 K

to 5,000 K. The Z (vertical)-axis demonstrates the IR

radiation power. A close examination of the graph

reveals the variations in IR patterns based on their

wavelength. While the longer wavelengths exhibit

shapes closer to a half sinusoid, the shorter wavelengths (2 _tm) have sharper envelopes with steeper

rising and falling edges. The envelopes of specific

wavelengths may be recognized by employing pattern recognition techniques; then they may be used

to measure the amount of radiation power within

the given wavelength range.

Because of time and budget constraints a complete prototype was not developed. The breadboard

setup provided enough information to support the

concept but required significant enhancements and

additions to be upgraded to a fully functioning

prototype.

Radiation measurement and analysis

The main factors that determine the quality of radiation measurement are the sensor noise and radiation

noise levels. Both reduction and characterization of

noise help enhance the quality of radiation

measurement.

Infrared radiation sensors are inherently sensitive to fluctuations in temperature. Therefore it is

critical that the temperature of the sensor be monitored and actively controlled. The IR sensor element

used is mounted on a thermoelectrically cooled

(TEC) plate. The temperature of the sensor was monitored using a thermistor, which was attached to the

TEC plate. The results indicated stable sensor temperature at-30°C, which allowed for low senSor

.... thermal noise.

Studies conducted in the area of digital signal

processing (DSP) indicated that DSP methods may

be used to improve the gas concentration

measurement.

Significance of the results

The efforts of the past year resulted in the identification of various subsystems and the design and construction of a breadboard CO2 analyzer unit to allow

experimentation with different components and

analyzer configurations. Feasibility studies indicated

that a miniature IR laser as well as a special type of

high energy flash bulb may be used as alternate IR

radiation sources in CO2 gas analyzers.

The feasibility studies also identified specific

miniature diode requirements to allow their development. Also project efforts have initiated a process

for a joint effort between NASA and commercial

companies to develop technology that is mutually

beneficial.

Successful implementation of either of the alternate IR radiation sources will eliminate the use of

traditional mechanical choppers or beam splitters.

The characteristics and performance of the IR radiation sensing subsystem, currently designed, will

meet design requirements. DSP methods may also

allow simultaneous multiple gas concentration

measurements.

Key words

Gas exchange, Photosynthesis, Respiration,

Transpiration
Radiation

Intensity

(_W.cm-2._m "1)

4 3OO

300

300 5000 300

Normalized

Figure 1. Black body electromagnetic radiation.

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Origins of Planetary Systems: Observations and Analysis

Investigator(s)

Kent Cullers, Ames Research Center,

Moffett Field, CA 94035-1000

Laurance Doyle, SETI Institute,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The detection of extrasolar planetary systems is of vital

importance to our understanding of the place our

planet has in the cosmos, the origin of our solar system

(whether it is unique or not), and an accurate estimate

of the number of possible habitable planets in our

galaxy. However, detecting extrasolar planetary systems is one of the most difficult observational problems in astronomy today, and each method has its

difficulties. The photometric method, which measures

a drop in the brightness of the star due to the transit of

a planetary body in the line-of-sight, is the most sensitive detection method, but it assumes that the planetary orbital plane is seen edge-on by the observer

(Borucki and Summers, 1984, Borucki et al., 1988). The

photometric method can detect a drop in the brightness of a star (1% for a Jupiter-sized planet and 0.1%

for an Earth-sized planet) due to the transit of a planet

in the line-of-sight (two-color photometry removes

ambiguities due to stellar variability, starspots, or limb

darkening; see Borucki and Summers, 1984; Schneider

et al., 1990; Schneider and Chevreton, 1990, 1991).

Even though this method is the most sensitive

(medium-sized, 30-in. telescopes can be used), it relies

critically on the condition that the planetary orbital

plane be in the observer's line-of-sight. This condition

exists because the orbital plane of the planetary system

has to be less than 2 ° from the line-of-sight of the

observer to obtain a measurable planetary transit.

Therefore, for a random distribution of planetary

orbital plane inclinations, over 1,000 stars would have

to be monitored for over a year to obtain one detection. This method is unique, therefore, in that with

present technology it is not detection limited, but

probability limited. This study will improve that probability in two ways: (1) We will preconstrain the likely

single star planetary orbital planes by compiling a catalogue of stellar rotation axes inclinations to the lineof-sight which, in turn, will give the expected

planetary orbital plane for single systems. We can then

designate ahead of time which systems are close

enough to being edge-on so that the photometric

detection method may be used. (2) We will monitor

eclipsing binary stars_which have expected planetary

orbital planes that are already edge-on, have two stars

with which to confirm a planetary transit, and have

stable planetary orbital regions that have been shown

to exist for most configurations of such close

systemsifor evidence of such extrasolar planetary

systems. This effort will occur during the second year

of funding.

Progress and results

This year is the first for this study, but we have

already determined the rotation axis inclination from

the line-of-sight for over 200 stars using stellar rotation

periods (determined from the CaII H&K emission line

spectra in the case of late-type stars and variations in

the magnetic field spectral lines in the case of earlytype stars; after Doyle, 1988). We expect to submit this

new stellar parameter catalogue for publication before

the end of this year. In the process of compiling this

catalogue we have also discovered a number of astrophysically interesting relationships between younger

and older stars, including indications that T Tauri stars

(premain sequence stars) have the same velocity distribution as stars already on the main sequence. This

result is significant in further revealing the actual

angular momentum processes that stars undergo during the planet forming stage.

Significance of the results

We are applying the above determinations to provide

improved detection statistics for the photometric

method_specifying a list of nearly edge-on systems to

be monitored (present accuracy is limited to about +8 °

at i = 90 °. This constraint would narrow the possible

number of stars in a sample that could be successfully

monitored for photometric detection of extrasolar

planets to about one-seventh the previous "'random"

sampling. Selection of infrared excess stars might further constrain this selection (Backman and Gillett,

1988; Doyle and Backman 1990). In addition, however,

this determination of expected extrasolar planetary

orbital planes can be very useful for the other detection methods.

For example, a specification of the planetary

orbital plane could remove proper motion and parallax vectors_large secondary effectsifrom the

expected astrometric wobble of a star caused by a

planetary system (Scargle, 1988; Levy et al., 1988).

Pole-on systems could also be specified for direct
imagingeffortsaswellaspreferredcandidatesfor

astrometricmeasurements(accuraciesof+0.5 ° can be

achieved at i -- 0°). One could also directly compute

masses of stellar companions obtained using the radial

velocity method. Some present measurements already

show very promising results if the system's inclination

can be calculated (Campbell et al., 1988; Robinson,

1990, where very low mass companions are indicated,

but these measurements await determination of the

sine of the inclination from the line-of-sight, i).

The photometric method for detecting extrasolar

planets benefits the most from this study and becomes

a very viable technique using existing modest equipment when the probabilities of detection can be

improved. We have outlined two major contributions

to this improvement. One is predetermining the

expected planetary orbital plane using asymmetries in

stellar atmospheres to derive the stellar rotation axes

inclinations, and the second is extending photometric

observations of eclipsing binary stars where the extrasolar planetary orbital plane is already expected to be

edge-on. Both results bring the observing tasks

required to detect extrasolar planetary systems to a

manageable level for a collaboration of this size and to

begin constraining the probabilities well enough so

that, in case of nondetections, significant knowledge

about extrasolar planets existing around some single

stars as well as short-period double stars may be

gained.

Publications resulting from study

We are planning to publish the first Catalogue of Stellar Rotation Axes Inclinations this year. We will be

applying these results in the second year of this DDF

research using the photometric method to detect extrasolar planetary systems around nearby single and

eclipsing binary stars.

References

Backman, D. E.; and Gillett, F. C.: IRAS Statistics on

Main Sequence Stellar IR Excesses and Models of

Circumstellar Particle Clouds in Bioastronomy. The

Next Steps, G. Marx, ed., Kluwer Academis Publ.,

Dordrecht, Holland, 1988, pp. 93-99.

Borucki, W. J.; and Summers, A.: The Photometric

Method of Detecting Other Planetary Systems.

Icarus, vol. 58, 1984, pp. 121-134.

Borucki, W. J.; Allen, L. E. ; Taylor, W. S.; Young, A. T.;

and Schaefer, A. R.: A Photometric Approach to

Detecting Earth-Sized Planets in Bioastronomy. The

Next Steps, G. Marx, ed., Kluwer Academis Publ.,

Dordrecht, Holland, 1988, pp. 101-112.

Campbell, B.; Walker, G. A. H.; and Yang, S.: The

Search for Substellar Companions to Solar-Type

Stars. Ap. J., vol. 331, 1988, pp. 902-921.

Doyle, L. R.: Progress in Determining the Space Orientation of Stars in Bioastronomy. The Next Steps,

G. Marx, ed., Kluwer Academis Publ., Dordrecht,

Holland, 1988, pp. 101-105.

Doyle, L. R.; and Backman, D. E.: Poster at Tucson

Protostars and Planets III Conference. Tucson,

Ariz., 1990.

Levy, E. H.; McMillan, R. S.; Gatewood, G. D.; Stein,

J. W.; Castelaz, M. W.; Buffington, A.; Nishioka, N.;

and Scargle, J. D.: Discovery/Study of Planetary

Systems Using Astrometry from Space in Bioastronomy. The Next Steps, G. Marx, ed., Kluwer

Academis Publ., Dordrecht, Holland, 1988,

pp. 131-136.

Robinson, E. L.; Cochran, A. L.; Cochran, W. D.;

Shafter, A. W.; and Zhang, E. H.: A Search for

Eclipses of HD 114762 by a Low-Mass Companion.

A. J., vol. 99, 1990, pp. 672--674.

Scargle, J. D.: Planetary Detection Techniques: an

Overview in Bioastronomy. The Next Steps,

G. Marx, ed., Kluwer Academis Publ., Dordrecht,

Holland, 1988, pp. 79-82.

Schneider, J.; Chevreton, M.; and Martin, E.: New

Efforts in the Search for Extrasolar Planets in Formation of Stars and Planets and the Evolution of the

Solar System. ESA SP-315, B. Battrick, ed., 1990,

pp. 67-71.

Schneider, J.; and Chevreton, M.: The Photometric

Search for Earth-Sized Extrasolar Planets by Occultation in Binary Systems. Astron. and Astrophys.,

vol. 232, 1990, pp. 251-257.

Schneider, J.; and Chevreton, M.: A Proposal for the

Search of Extrasolar Planets by Occultation in

Bioastronomy. The Search Broadens, J. Heidmann

and M. Klein, eds., Springer-Verlag, 1991, p. 33.

Key words

Extrasolar planets, Stellar inclinations, Star spots
Monitoring Global Change During the Last 10,000 Years

Investigator(s)

Hector L. D'Antoni, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

1. To compare two environmental processes

developed within the last 10,000 years in two independent regions by means of pollen analytic and

remote sensing data.

Z To calibrate predictive tools to hindcast postglacial vegetation processes in southwestern Oregon

and Southern Patagonia and Tierra del Fuego in terms

of remote sensing.

3. To produce new data and to interpret both

new and current data in terms of vegetation history,

nitrogen, and carbon and water fluxes.

Progress and results

There is not sufficient information yet to compare both

regional processes. However, the literary search on

Oregon found an extensive work by Calvin Heusser

(1960) mostly restricted to Pacific environments of

Oregon. Some 25 sites were studied by the late Henry

Paul Hansen from 1930-1950. By the time of the development of the 14C dating method by W. Libby in 1949

(Libby, 1954), Hansen produced very little. Therefore,

most of his valuable and still original work for the

interior of Oregon is no longer in use. I collected all

these papers and I studied the data with modern statistical techniques. I will be trying to recruit a graduate

student who would revisit the sites and take carbon

samples from Hansen's stratigraphies in order to get

them 14C dated.

In 1993 M. Spanner and I published a work using

only modem data (Spanner and D'Antoni, 1993). Later

I tested these models on pollen data from six sedimentary profiles ranging from 3,500 to 12,000 years BP

(before present). Results were summarized in a communication and a poster at the 26th meeting of the

American Association of Stratigraphic Palynologists

(A_ASP): Pollen Analysis in Southern Patagonia: from

Space to Time. My presentation was attended by not

only the A_ASP members but also some 10 specialists

from the American Geological Association (that also

was holding a meeting in San Diego). Currently I am

preparing a paper on this work. While setting the

palynology laboratory, I also was restudying an

important pollen profile from central Mexico. I identified a problem in the published work (by Straka and

Ohngemach) and using numerical models I produced

two paleotemperature curves for central Mexico for

the last 10,000 years. A paper, Paleotemperatures of

La Malinche: A Palynological Hypothesis, was peer

reviewed and accepted by Grana and is currently in

press. As a result of the last three papers I published in

Grana, the chief editor, Mervi Hjelmroos, visited Ames

to see the pollen laboratory I created with DDF funds.

She was well impressed by our facilities. I discussed

some of these topics in the Early Detection of Global

Change Workshop held at the Aspen Global Change

Institute, Colorado.

New data are currently being produced for

Oregon (modem pollen) and Tierra del Fuego and

southern Patagonia (aspartic acid racemization). More

data are needed for comparisons. The subjects of

water, nitrogen and carbon fluxes that are available for

Oregon faced us with a difficult problem in southern

South America. In fact, due to the process of ozone

depletion over mid latitudes, it is possible that there

are no more "pristine" conditions in Patagonia. This

project encouraged me to submit a research project to

NASA Headquarters and, since the problem has never

been studied at the terrestrial ecosystem level, I asked

50 top scientists (including some colleagues from

Ames) to review the project. With no exceptions I

received positive reviews and encouragement to submit the proposal. I also received positive comments

from NASA Headquarters. Later, I discussed this matter at the Early Detection Workshop in Aspen. In due

time I will report to the Chief Scientist on these

matters.

Significance of results

Results are showing that the proposed method works

correctly and the difficulties we faced lead us to open a

new research area of great scientific significance.

References

D'Antoni, Hector L.; and Spanner, Michael: Remote

Sensing and Modem Pollen Dispersal in Southern

Patagonia and Tierra del Fuego (Argentina): Models for Palaeoecology. Grana, vol. 32, 1993,

pp. 29-39.

Heusser, Calvin J.: Late-Pleistocene Environments of

North Pacific North America. An Elaboration of

Late-Glacial and Postglacial Climatic, Physiographic, and Biotic Changes. American Geographical Soc., Special Publ. No. 35, New York, 1960.

10
Libby, Willard: Radiocarbon Dating. Endeavour,

vol. 13, Pergamon Press, Oxford, 1954, pp. 5-16.

Key words

Quaternary environments, Palynology and remote

sensing, Paleoclimate and climate prediction

11
Schmidt-Cassegrain Long-Range Laser Velocimeter

Investigator(s)

Stephen E. Dunagan, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Full-scale aeronautical test programs utilizing the

NFAC wind tunnels require the best available measurement instrumentation. Laser velocimetry (LV)

provides an important noninvasive method for the

measurement of velocity at a point. The design of a

suitable instrument for the large NFAC wind tunnels

faces technical challenges in the areas of test section

access, optical aperture, laser power, and flow seeding.

Progress and results

A two-component dual-beam LV system for the

40- x 80-Foot Wind Tunnel has been designed and is in

the process of fabrication. The instnm_ent design is

based on the use of high quality, large aperture

Schmidt-Cassegrain telescope optics to perform both

the laser-beam-focusing and scattered-light-collection

functions. Uncoupled orthogonal measurement of two

coordinates of velocity may be made. To avoid the

need for large, high quality windows in the test section, the instrument is configured as a streamlined

optical assembly mounted on the floor of the test section and translated in the streamwise and cross-stream

directions. The laser velocimeter probe volume is

translated in the vertical direction by means of zoom

optics. Coaxial back-scattered light is collected

through the same optical system and analyzed for

Doppler shift. Single-mode polarization preserving

fiber-optics transmit light from the remotely located

laser into the optical assembly. A multimode fiber

conveys the scattered light to remotely located photodetectors. Frequency domain signal processing will

permit analysis of the Doppler signal with a very poor

signal-to-noise ratio.

A prototype optical system has been set up and

evaluated in the optics lab. Results to date show promise, with high signal to noise ratio as the primary

indicator. Some problems have arisen as well; in particular, the very small number of fringes present in the

probe volume is problematic for digital Fouriertransform burst-signal processing schemes. An alternative digital autocorrelation processing scheme is

presently being investigated.

Significance of the results

These results are adequate to prove the viability of the

design concept. Designs for a prototype instnm:ent

pod and traverse have been completed. Fabrication

and assembly of the instnament will proceed on an

aggressive schedule with anticipated wind tunnel

deployment on the High Speed Research Test in

November 1993.

Publications resulting from study

A paper is presently in process that describes the

design and application of the instrument. It will be

presented at an appropriate aerospace instrumentation

forum as soon as experimental data are available for

inclusion.

Key words

Laser Doppler velocimeters, Flow measurement, Wind

tunnels

12
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Investigation of the Scales of Turbulence in Hypersonic

Rarefied Flow

Investigators

William J. Feiereisen, Ames Research Center,

Moffett Field, CA 94035-1000

Donald Baganoff and Sanjiva Lele,

Stanford University, Stanford, CA 94305

Other personnel involved

Avijit Goswami, Stanford University,

Stanford, CA 94305

Objectives of the study

Turbulent flows are composed of eddies of a wide

range of sizes. Direct simulations attempt to accurately

reproduce all the size and time scales in a flow, against

which turbulence models may be compared or turbulent flow physics studied. Similitude arguments,

which have traditionally been employed to estimate

this range of scales, have led to conclusions that the

smallest spatial scales in the flow, characteristic of the

eddies that dissipate the turbulent kinetic energy, are

much larger than the mean free path and, therefore,

viscous shear stress and heat transfer as modeled by

the Navier-Stokes equations are properly represented.

The parameters of these arguments have been chosen

to represent normally encountered turbulence consistent with flows of engineering interest such as aircraft

or turbomachinery. For hypersonic vehicles, which fly

in the upper atmosphere, it is appropriate to reassess

these arguments to determine if turbulent flow can

exist under conditions where the smallest scales are no

longer properly modeled by the linear transport terms

of the Navier-Stokes equations. If turbulent flow can

exist at the low Reynolds numbers in this flight

regime, then a standard similitude argument suggests

that the smallest eddies are in the free-molecular/

continuum transition regime and a stochastic direct

simulation would be required in order to properly

represent the turbulent dissipation. In this light, it was

the objective of this work to investigate the following

three questions:

1. Can turbulence exist under conditions corresponding to high speed flight in the upper

atmosphere?

Z Do the dissipation length scales become of the

same order of magnitude as the mean free path and

what implication would this have for the modeling of

these scales?

3. Can a Monte-Carlo simulation method be

used to produce a direct simulation of turbulent flow

under rarefied conditions?

Approach

Simulations of isotropic homogeneous turbulence

were performed by two completely different methods,

each recognized as appropriate for application in its

flow regime. The continuum flow regime was modeled

with a direct Navier-Stokes solver (DNS). This method

solves the full Navier-Stokes equations on a finitedifference mesh. The continuum assumption is

implicit in its use of linear constitutive relations for

viscous stress and heat flux. The spatial derivatives are

approximated using a compact sixth-order accurate

finite-difference scheme and time advancement is carried out using a fourth-order Runge-Kutta scheme

(Lele, 1992). The rarefied flow scheme is a version of

the Direct Simulation Monte-Carlo method adapted to

vector architectures (McDonald, 1988). It models the

gas using discrete particles that communicate through

collisions by exchange of momentum and energy. It

relies on a stochastic approach to model collisions as

opposed to tracking the history of each individual

particle through a binary encounter. The domain is

discretized into a finite number of cells whose main

function is to identify possible collision partners. The

collision frequency is set so as to produce the right

macroscopic behavior. The time step is chosen to be

small so that one may decouple collisions and free

migration of particles at each time step. Since the particle simulation is based on a stochastic method, its

accuracy depends partly on the chosen sample size

(number of particles per cell). Increasing the sample

size per cell reduces the statistical variations in the

results.

Initial study has involved simulations in two

dimensions, recognizing that turbulent physics

requires the third dimension. Identical velocity fields

of isotropic homogeneous turbulence were created to

use as initial conditions for Navier-Stokes code and

for a discrete particle simulation code.

This study focuses on a comparison between the

predictions of the two simulation techniques by studying the temporal decay of a simple two-dimensional

fluctuating flow in a square box with periodic boundary conditions. The initial state of the flow is given by

.... iii_i!_!i,"iI

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13
constant pressure and temperature throughout and a

velocity field that characterizes homogeneous and

isotropic turbulence of an incompressible fluid. Since

the flow is constrained to remain two dimensional,

there can be no stretching of vortex lines and hence no

further production of turbulent kinetic energy. Therefore, one may only study the problem of turbulence

decay in two dimensions. Comparisons are first made

in the near-continuum regime where the two methods

are expected to agree and then carried out under more

rarefied conditions where the two are expected to

exhibit differences. The Knudsen number, Kn, defined

as the ratio of the mean-free path length for the molecular motion to some characteristic length in the flow, is

a measure of the degree of rarefaction in the flow and

is an important parameter in studying possible differences between the two predictions.

In order to make comparisons in a time dependent

problem, it is necessary to assure that the two simulations are initialized at exactly the same conditions.

Although both methods employ nondimensional variables, the governing parameters in the two are quite

different. In DNS the main parameters are the initial

reference Reynolds number. In a particle method, one

of the most important parameters is the Knudsen

number, Kn.

In the DNS code, the initial velocity field was chosen such that it was divergence free and had a magnitude equal to the specified value of the rms Mach

number. In addition, it satisfied a specified initial

energy spectnm_ function in Fourier space with the

phases of the velocity components chosen at random.

In order to match the initial velocities in the two

schemes the resultant values from the DNS initialization were input directly into the particle simulation.

This input ensured that the same initial Mach number

and energy spectra were being used in the two codes.

The temperature and pressure distributions were set to

be uniform, initially. Whereas this implementation is

trivial in the Navier-Stokes simulation, it requires

careful consideration in the Monte-Carlo method.

Here, the particle velocities for each cell have to be

picked from a velocity distribution function, f, which

has a given temperature (variance) and a given fluid

velocity (mean).

In this comparative study, the initialization procedure was found to be very important. In particular, the

choice of the initial velocity distribution function in the

particle method plays a key role because it sets the initial state of stress and hence the initial decay rate of the

mean fluctuating kinetic energy. The spherical

Maxwellian distribution was found to be overly simplistic because it does not produce a shear stress. The

use of an ellipsiodal distribution based on the NavierStokes state of stress fails when this stress becomes

nonphysical, which occurs for Knudsen numbers of

5/32 and above.

Liu and Lees (1961), however, proposed an

approximate method for the solution of the Couette

flow problem that may be used as a starting point for

the construction of a suitable velocity distribution.

They assumed a two stream Maxwellian with no temperature gradient across the plates. If the initial strain

rate field in a cell is imagined to be created by a

Couette flow, it is possible to use Liu's and Lees' distribution to initialize the particle simulation.

The initial divergence-free strain rate field

obtained from the Navier-Stokes initialization is

rotated to an orientation that corresponds to pure

shearing strain. In general, it is possible to decompose

this shearing strain field in each cell into a Couette

flow plus a rotation. Since the initial temperature field

is uniform throughout the box, the assumption of no

temperature gradient across the plates holds. In the

process of producing Liu's and Lees' distribution from

the strain rate field, it is apparent that the effect of the

rotation on the velocity distribution function has been

ignored. In order to use their method, it is necessary to

be able to show that f is invariant under rotation. It has

been shown that f indeed satisfies this condition under

a general Euclidean group of transformations

(Speziale, 1981).

Test cases were then run using Liu's and Lees'

velocity distribution function to initialize the particle

method. The Knudsen number was varied through the

sequence 1/32, 2/32, 5 / 32, and 8/32. The rms fluctuating Mach number was fixed at 0.4. The problem of

nonphysical stresses that were being encountered in

using the Navier-Stokes state of stress to define the

ellipsoidal distribution was now successfully eliminated. The temporal decay of mean kinetic energy thus

obtained is shown in figure 1. Whereas the DNS and

the particle method showed close agreement for values of Kn of 1/32, 2/32, and 5/32, some differences

began to be observed for Kn = 8/32. For the last case,

the DNS overpredicts the amount of decay. This overprediction is a consequence of its linear constitutive

stress-strain law, which tends to overpredict the shear

stress at higher values of Kn. Figures 2 and 3 show the

calculated energy spectra for Kn = 1/32 and Kn = 5/32

and indicate relatively close agreement between both

methods for the continuum and, surprisingly, for the

rarefied case also.

Liu's and Lees' velocity distribution function

worked well for the range of test conditions studied.

The temporal decay of the mean kinetic energy

showed a near perfect agreement at a Knudsen number of 1/32, which represents the near continuum,

14

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10-2

Kn = 1/32

KR

Kn = 2/32

%

%

%

%

%

%

%

_Kn = 8/32

.5 1.0 1.5

Fraction of eddy turnover time (t/'C)

2.0

Figure 1. Kinetic energy decay.

100 --- i

10-1 _-

10 -2 _-

10-4 F

10 -5

I

uJ

10 -3

IJJ

10-6

I I I ,.L I I I

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o DNS

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I I I I I I

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Radial wave number (k)

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-'am

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(9

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Figure 2. Turbulent kinetic energy spectra for Knudsen

number 1/32 at t = tau.

and a reasonably good agreement up to a Knudsen

number of 5/32. Since this range is believed to cover

much of the regime of practical interest, it indicates

that the DNS can continue to be used in flows having a

100

10-1

10-2

uJ

v

10-3

A

uJ

10-4

10-5

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Radial wave number (k)

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- _ DSMC =

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Figure 3. Turbulent kinetic energy spectra for Knudsen

number 5/32 at t = tau.

reasonable degree of rarefaction. Beyond this point the

DNS overpredicted the amount of decay.

This work indicates that direct Navier-Stokes

simulations of turbulent flow are valid much farther

into the rarefied flow regime than was previously

thought. This conclusion, based upon comparisons of

the decay rate of turbulent kinetic energy and the form

of the calculated energy spectra, does not fit with previous ideas of the viscous behavior of fluids at high

Knudsen numbers. This discrepancy occurs possibly

because the velocity gradients as calculated are much

smaller than those that are seen in shock waves where

non-equilibrium effects determine the structure. Even

though the small eddies are in the traditional rarefied

flow regime, as characterized by the Knudsen number,

a more useful measure of the applicability of the DNS

is probably related to a measure of the velocity gradients rather than a Knudsen number based on the size

of the small eddies. Other higher order statistical measures of turbulence will need to be compared before

this conclusion can be completely upheld. If it is

upheld, however, DNS simulations can form the basis

for turbulence modeling advancements on hypersonic

flows while sparing the expense of Monte-Carlo

simulations.

15
Publications resulting from the study

Goswami, A.; Baganoff, D.; Lele, S.; and Feiereisen, W.:

A Comparative Study of Turbulent Decay Using

Navier-Stokes and Discrete Particle Simulations.

45th Annual Meeting, Fluid Dynamics Division,

American Physical Society, Florida State University,

Nov. 22-24, 1992.

Goswami, A.; Baganoff, D.; Lele, S.; and Feiereisen, W.:

A Comparative Study of Turbulent Decay Using

Navier-Stokes and A Discrete Particle Simulation,

AIAA-93-3093, AA 28th Thermophysics Conference, Orlando, Fla., July 6-8, 1993.

References

1. Lele, S. K.: Compact Finite Difference Schemes

with Spectral-Like Resolution, J. Computational Phys., No. 103, 1992.

2. Lfu, C.; and Lees, L.: Kinetic Theory Description

of Plane Compressible Couette Flow.

Advances in Applied Mechanics, Suppl. 1,

Rarefied Gas Dynamics, Academic Press, 1961,

p. 391.

3. McDonald, J. D.; and Baganoff, D.: Vectorization

of a Particle Simulation Method for Hypersonic Rarefied Flow. AIAA Thermophysics,

Plasmadynamics, and Lasers Conference,

No. 88-2735, 1988.

4. Speziale, C. G.: On Frame Indifference and Iterative Procedures in the Kinetic Theory of Gases,

International J. Engineering and Science,

vol. 19, 1981, pp. 63-73.

Key words

Rarefied flows, Direct simulation Monte-Carlo,

Turbulence simulations

16
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Analytical and Experimental Studies of Rotorcraft

Vertical Climb Performance

Investigator(s)

Fort F. Felker, Ames Research Center,

Moffett Field, CA 94035-1000

Robert M. McKillip

Continuum Dynamics, Inc.,

Princeton, NJ 08543

Introduction

The accurate prediction of rotorcraft vertical climb

performance is a challenging problem in rotorcraft

aerodynamics. It is not uncommon for the most

widely used vertical climb performance analysis

method (momentum theory) to overpredict the

power increment required to climb by 50% or

more. The lack of an accurate analysis creates a

severe difficulty during the development of a new

helicopter. The U.S. Army specifies a minimum

level of vertical climb performance that is acceptable and imposes severe penalties if a newly

developed helicopter cannot meet the specification. Since the analysis is not accurate, it is impossible to know whether or not a proposed design

can meet the specification until testing of the prototype helicopter is under way. At that point in the

development cycle, design changes to meet the

specification are very costly.

A combined theoretical and experimental

investigation into rotorcraft performance in vertical climb was completed with the objective of

providing an accurate analytical capability to the

U. S. rotorcraft industry. High-quality performance data were acquired in the Princeton Long

Track. This facility allowed for the model to be

moved through still air in a controlled environment, eliminating the uncertainties in axial flight

speed and wall interference effects common in

low-speed wind tunnel tests. An improved

boundary condition was developed for a state-ofthe-art free-wake analysis. The improved analysis

provides superior results when compared with the

methods typically used by industry.

Experimental results

An 8-ft-diameter four-bladed hingeless model

rotor was used in the experiments at the Princeton

Long Track. The model was mounted on a traversing carriage with the rotor shaft horizontal. The

speed of the carriage could be precisely controlled,

eliminating any uncertainty in the axial flight

velocity. A six-component balance was used to

measure rotor forces, moments, and torque. The

collective pitch was held constant during each

data run (with zero cyclic), and two different collective pitches were examined in the test.

Figure I shows the variation in rotor thrust

with axial flight velocity, and figure 2 shows the

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Figure 1. Effect of vertical climb velocity on measured

rotor thrust coefficient.

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.00055

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Figure 2. Effect of vertical climb.velocity on measured

rotor torque coefficient.

17
variation in rotor torque. These data were

obtained with a collective pitch of 10.9 deg, giving

a nominal hover thrust coefficient of 0.00615.

Because the data were acquired at fixed collective,

increasing the vertical climb velocity reduces sectional angles of attack on the blade and reduces

the thrust coefficient. In spite of the reduced

thrust, the rotor torque increases with increasing

climb velocity up to a nondimensional climb

velocity of 0.5, where the reduction in thrust is

finally large enough to cause a corresponding

reduction in torque.

Analytical results

Predictions of rotor performance in vertical climb

were made using the free-wake analysis EHPIC

and the commonly used momentum theory. A

new tip vortex boundary condition was developed

for EHPIC, which allows the tip vortex to more

closely follow the experimentally observed tip

vortex geometry in the near-wake region just aft of

the blade trailing edge.

Figure 3 presents a comparison of the predicted and measured rotor thrust in vertical climb,

and figure 4 presents a comparison of the predicted and measured rotor torque, using the freewake analysis. The data were acquired with a

collective pitch of 10.9 deg (as in figs. I and 2). For

the analysis, the collective pitch was slightly

reduced (to 10.6 deg), so that the predicted and

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D

.oo5o D

EHPIC

.0045 I I I I

0 .2 .4 .6 .8 1.0

Vc/V h

Figure 3. Comparison of predicted and measured rotor

thrust coefficients using a free-wake analysis. Collective

pitch held fixed.

CQ

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.00050

D

_D _ D

D

EHPIC

[2

D

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0 .2 .4 .6 .8 1.0

Vc/V h

Figure 4. Comparison of predicted and measured rotor

torque coefficients using a free-wake analysis. Collective

pitch held fixed.

measured thrust coefficients would match in

hover.

Figure 3 shows that the analysis underpredicts

the thrust as the climb velocity increases, although

the slope of the thrust versus climb velocity curve

appears to be correct at the higher climb velocities.

Figure 4 shows that the analysis overpredicts the

rotor torque in hover by 3.8%. The errors in predicted torque in hover typically range from 0-5%

with this analysis, so the error in hover is within

the expected range. Figure 4 also shows that the

increase in torque as the vertical climb velocity

increases is underpredicted (consistent with the

underprediction in thrust).

The results in figures 3 and 4 suggest that better predictions could be obtained if the collective

pitch used in the analysis were allowed to vary in

order to match the observed thrust coefficient.

This was done, and the results are shown in

figure 5. This figure shows that the shape of the

power versus vertical climb velocity curve is well

predicted by the free-wake analysis. The offset in

power is fairly constant over the range of climb

velocities, which suggests that there is an error in

the profile power prediction (from airfoil tables).

The results shown in figure 5 represent a substantial improvement in predictive capability when

compared with the results obtained using momentum theory.

18
CQ

"00060 r

.00055

.00050

[1

!-'1

I I I I

.00045 I

0 .2 .4 .6 .8 1.0

Vc/V h

Figure 5. Comparison of predicted and measured rotor

torque coefficients using a free-wake analysis. Collective

pitch adjusted to match thrust.

descent has been completed. New high-quality

experimental data were obtained, which are free of

uncertainty in axial flight speed and wind tunnel

wall effects. An improved boundary condition was

developed for a free-wake analysis. The modified

analysis provides more accurate results than the

commonly used momentum theory. See Felker

and McKillip (1994) for more details.

References

Felker, Fort F.; and McKillip, Robert M.: Comparisons of Predicted and Measured Rotor Performance in Vertical Climb and Descent.

Proceedings of the 50th Annual Forum of the

American Helicopter Society, Washington,

D.C., 1994.

Key words

Helicopter, Aerodynamic performance, Rotor

performance

Concluding remarks

A combined theoretical and experimental investigation of rotor performance in vertical climb and

19
Continuous-Flow Apparatus for Studies of Gas- and

Liquid-Phase Adsorption Dynamics

Investigators

John E. Finn and Sanford S. Davis,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Phuong Nguyen, De Anza College,

Cupertino, CA 95014

Bradley Davis, University of California,

Santa Barbara, CA 93106

Bruce DeVantier, Southern Illinois University,

Carbondale, IL 62901-6603

Glenn Deardorff, Sterling Federal Systems,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Spacecraft life support system designs usually include

several subsystem components that use adsorption

directly or indirectly to remove excessive or unwanted

chemical species from fluid streams. These components include devices for CO2 removal, gas-phase

trace contaminant control, water purification and

polishing, and contaminant monitoring. Adsorptionbased processes will likely be important to future generations of life support systems as well, as adsorption

processors usually have several characteristics that

make them attractive for fluid purification in space

environments. A partial list includes simple construction and passive operation, good energy efficiency,

applicability to both gas and liquid streams, and

potentially regenerable operation.

This work focuses on applying some new numerical techniques to modeling the complex adsorption

column behavior seen in life support applications, and

designing and building new experimental equipment

for validating those techniques and models. The

modeling work uses a finite difference method based

on a discrete dispersion relationship developed originally for wave problems in acoustics (Davis, 1989,

1991) to solve the diffusion-convection-reaction equation that results from a differential mass balance on an

adsorption column. Solutions to this set of nonlinear,

strongly coupled partial differential equations are sets

of waves often having steep fronts that prove to be

challenging problems for numerical methods

(Finlayson, 1992).

The experimental objective of the work is to

assemble an apparatus for combining contaminant

species with a gas stream whose composition, flowrate, and humidity are carefully controlled, pass ing

the stream through a test adsorption column at a

controlled temperature, and analyzing the column

effluent for multiple contaminant species on a continuous basis. The data obtained can be compared with

results from numerical simulation. ......

Progress and results

Experimental work

During this period most of the work went into building and testing the experimental apparatus. An abbreviated schematic of the equipment is shown in

figure 1. The general flow of the process air stream is

easy to follow, but some of the particular techniques

used to meet the experimental objectives are worth

pointing out.

Producing an air stream whose relative humidity

can be specified and quickly varied between 0 and

95÷% at temperatures from 10 ° to 50°C is often difficult due to mass transfer limitations. This problem was

solved here by using a compact hydrophobic hollow

fiber membrane module (Hoechst-Celanese,

5PCM-106). De-ionized water flowing through the

tube side at a pressure higher than the gas (shell-side)

pressure humidifies the gas completely. At all

flowrates studied to date (to 5 standard liters/rain),

the gas emerges from the module virtually at the dewpoint without entrained water. The mass flowrate of

this stream and that of a stream of dry air are maintained at a ratio; humidification and mixing of these

streams are performed at a specified temperature to

produce a combined stream with the desired

properties.

Continuous analysis of the effluent stream by

mass spectroscopy proved to be impossible for our

analyzer (Hewlett-Packard 5971) due to the high ion

source pressure caused by the constant presence of

nitrogen. To solve this problem we turned to rapid

chromatography of relatively frequent (30-sec interval)

samples of the stream. For our initial experiments on a

stream containing CO2 and water, a short (5 cm)

packed column with an appropriate sorbent was used.

The method we developed delays the entry of CO2

and water into the detector until just after the N2 plug

exits. Using this method we achieved nearly

20
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Figure 1. Simplified schematic of apparatus for studying adsorption column dynamics.

continuous process monitoring and very high sensitivities (<1 ppm).

Data acquisition from pressure and temperature

sensors and control of the mass spectrometer are performed with one computer. Also, the equipment is

designed so that adsorption columns being studied

can be regenerated online and easily exchanged.

Inves tigations of other gas processors, such as catalytic

oxi dizers, are easily performed on the same

equipment.

Sample results from the apparatus are shown in

figure 2. The figure shows the breakthrough of CO2

from an adsorption column containing 13X zeolite

molecular sieve (UOP, 1/16 in. pellets). The CO2 concentration in the effluent is higher than that of the inlet

by approximately 40% due to displacement of

adsorbed CO2 by water. This "rollup, effect, a result

of strong interactions between water and CO2 in the

adsorbed phase, is one of several phenomena in air

revitalization system design that are important to

understand and simulate accurately.

Modeling work

Significant progress in the numerical and modeling

work was made by Prof. Bruce DeVantier. In particular, a finite element analog to the discrete dispersion

relation finite difference method was obtained;

21

96,000

£:

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0

_ 48,000

0

_ 24,000 "0

cO 10 20 30 40 50

Time, min

60 70 80

Figure 2. Carbon dioxide concentration in column effluent

from a typical experiment: 0.5% CO 2, balance N2 at 20°C

and 42% relative humidity, 1,000 standard cm 3/min ?qow -

ing through a 10 × 1.9 cm column of 13X zeolite molecular

sieve. The figure shows abundance of mass 44 ions as a

function of time in minutes. Peaks at start of run are samples of the column inJluent.

the analog may allow more natural handling of

boundary conditions and nonlinearities and is still

being investigated.

Simulations using the model for adsorption from

multicomponent gas streams produces large amounts

of numerical information. This information is much

easier to assimilate using scientific visualization
techniques.Ames'AdvancedGraphicsLaboratory

assistedusby developingatoolforuseonSilicon

Graphicscomputerworkstations.Thetoolanimates

themultiplewavesthataresolutionstothemodel

equation,allowingoneto easilyseetheconsequences

ofinteractionsbetweenadsorbedspecies.

Significance of the results

This work has produced several important results in

both modeling and experiments. The modeling work

provides the basis for high accuracy and computationally efficient simulations of multicomponent

adsorption column behavior. The work is critical to

safe and reliable operation of adsorption-based processors in life support systems for long-duration space

missions. Because of its general nature, it can also be

used for applications outside of life support.

The versatile apparatus constructed, which is

essential to the continuing validation work on the

models, required development of analytical methods

for near-continuous process monitoring. The use of a

mass spectrometer enables us to analyze a gas stream

for many chemical species simultaneously with one

analytical instrument and with very high sensitivity.

Publications resulting from study: None so far.

References

Davis, S.: A Space-Time Discretization Procedure for

Wave Propagation Problems. NASA TM-102215,

1989.

Davis, S.: Low-dispersion Finite Difference Methods

for Acoustic Waves in a Pipe. J. Acoust. Soc.

America, vol. 90, 1991, pp. 2775-2781.

Finlayson, B. A.: Numerical Methods for Problems

with Moving Fronts. Seattle, Wash." Ravenna Park

Publishing, 1992.

Key words

Adsorption column dynamics, Finite difference, Air

revitalization .....

22
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Development of Modal Filtering Techniques for Online

Estimation of Structural Vibration Parameters

Investigator(s)

Lawrence C. Freudinger,

Dryden Flight Research Facility

Edwards, CA 93523-0273

Other personnel involved

Stuart J. Shelley and Randall J. Allemang,

University of Cincinnati

Cincinnati, OH 45227-0072

Objectives of the study

Monitoring the dynamic characteristics of a vibrating

mechanical system is currently a time consuming and

expensive undertaking, but is often necessary from a

safety or health maintenance perspective. A specific

example familiar to the investigator is flight flutter

testing and aeroservoelastic flight testing of aircraft.

The objective of this work is to develop a new concept

called discrete modal filtering for the purpose of monitoring the vibration characteristics of mechanical

systems.

Discrete modal filters are essentially coordinate

transformations that take advantage of certain properties of a mechanical system's vibrating shapes (modal

vector orthogonality) in order to separate and condense measured information (sensor arrays) into less

but more meaningful data. This concept can be

exploited to improve the effectiveness of future online

estimation schemes for vibrating systems.

Progress and results

Discrete modal filtering was successfully used to

implement an online modal state monitor for a slowly

time-varying truss structure. This online monitor was

actually demonstrated at the International Modal

Analysis Conference in February 1993, in the technology exhibit area. The demonstration utilized 47

response sensors and tracked a single mode with

updates every 10 seconds. This demonstration served

as proof-of-concept for online modal parameter

monitoring using modal filters.

A study was subsequently undertaken to investigate the effect of modal filtering on the variance of the

estimated modal parameters. However, it became

apparent during the course of this study that meaningful comparisons were too difficult because the

estimation algorithms that were being used could not

provide variance estimates in a straightforward

fashion.

An unexpected spinoff from this study was the

necessary reformulation of classic experimental modal

parameter estimation algorithms into a robust time

domain algorithm that also produces empirical variance estimates for modal frequency and damping and

is surprisingly simple to use. It is a null space

approach which is related to a type of identification

approach known as subspace identification. The study

is continuing using the null space estimation

algorithm.

As of this writing, investigations are ongoing to

explore both practical as well as more esoteric aspects

of discrete modal filters. First, discrete modal filters

are being used in aircraft vibration tests and the results

compared to established approaches. Second, the identification of feedback mechanisms using a model reference approach is under study as an application

benefiting from the use of modally filtered data. Third,

the identification of modal filters and subsequent

updating based on new information is being reformulated in an H-infinity framework in order to incorporate uncertainties and to better understand overall

observability of modal filters. Fourth, and perhaps

most significantly, an unsolicited proposal seeking to

implement modal filtering and distributed data

processing options in commercially available data

acquisition software has been recieved by NASA and

is currently being considered. All these items are a

direct result of reports and presentations made by the

researchers on this project.

Significance of the results

The significance of the work started here is that experimental modal test methodologies of the future will

likely incorporate online algorithms that use sensor

array data that have been condensed to more manageable and meaningful information using discrete modal

filters. Users of the new technology should be able to

conduct vibration tests in much less time and, given

improved data analysis tools in an online environment, assimilate the meaning of the measurements

online as well. Some Star Trek fans cannot help but see

this concept summarized many times on television via

the phrase "Captain! Sensor arrays indicate .... "

23
Publications resulting from study

Freudinger, Lawrence C.; Shelley, S. J.; and Allemang,

R. J.: Online Parameter Estimation Using the Discrete Modal Filter. Final Report for NASA Ames

Research Center University Consortium, Lnterchange NCA2-642, June 1992.

Shelley, Stuart J.; Freudinger, L. C.; and Allemang,

R.J.: Development of an Online Parameter Estimation System Using the Discrete Modal Filter.

Tenth International Modal Analysis Conference,

San Diego, Calif., Feb. 3-7, 1992, pp. 173-183.

Shelley, Stuart J.; Freudinger, L. C.; and Allemang,

R. J.: Development of an Online Modal State

Monitor. Eleventh International Modal Analysis

Conference, Kissimmee, Fla., Feb. 1-4, 1993,

pp. 173-183.

Freudinger, Lawrence C.; and Field, Richard V., Jr.:

Null Space Pole Estimation with Error Bounds.

Twelfth International Modal Analysis Conference,

Honolulu, Hawaii, Jan. 31-Feb. 3, 1994.

Key words

Vibration mode, Spatial filtering, Modal response

24
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Computational Modeling of Femtosecond All-Optical

Switches Directly from Maxwell's Equations

Investigator(s)

Peter M. Goorjian, Ames Research Center,

Moffett Field, CA 94035-1000

Allen Taflove, Northwestern University,

Evanston, IL 60208

Other personnel involved

Rose M. Joseph and Susan C. Hagness,

Northwestern University, Evanston, IL 60208

Objectives of the study

Intense activities are under way in photonics to

develop all-optical switching devices. Experimenters

have produced all-optical switches capable of

100-femtosecond responses using light pulses. Also,

there are experimental observations of spatial soliton

interactions, which could be used for optical switches.

The applications are to advanced digital signal processors and optical computers. Optical processors are

potentially 1,000 times faster than electronic computers. They are expected to be capable of 1013 operations

per second, compared to 1010 operations per second of

current electronic computers, such as the Cray-90.

Optical signal processors could interface directly with

ultrawideband optical fiber communications systems.

The main development that is needed for optical circuits is to develop femtosecond all-optical switches

and logic gates.

The need for a new algorithm to aid in this

research is based on the following considerations.

Laboratory construction alone without computer simulations would be prohibitively lengthy and costly.

However, current methods, both computational and

analytical, use the nonlinear Schrodinger Equation

(NLSE), a scalar equation, to approximate MaxweU's

equations, which are a system of vector equations.

Hence the NLSE neglects the vector wave effects. Also

the NLSE omits the optical carrier of the electromagnetic pulse. By using the full vector nonlinear Maxwell

equations, the electromagnetic field can be more accurately modeled in applications to 2-D and 3-D integrated optical circuits with characteristic dimensions

close to the optical wavelength, i.e., on the order of 0.1

to 10 optical cycles.

The objectives of this study are the following. The

initial goal is to develop algorithms and computer

codes for modeling femtosecond all-optical switches

and logic gates on a 10-nanometer distance scale with

the full-vector, nonlinear Maxwell equations. As part

of this objective, a capability will be developed to

model nonlinear optical materials, including linear

and nonlinear, instantaneous and dispersive effects in

the electric polarization in material media. The next

step will be to develop a capability to model

millimeter-scale 2-D and 3-D integrated optical circuits. In this stage the optical carrier of the electromagnetic field will be retained so that interactions of

the pulses with geometry features on the size of the

optical wavelength, such as material inhomogeneities,

(e.g., crossing fibers), can be accurately modeled. The

final step will be to use the codes to develop candidate

designs for femtosecond all-optical switches, logic

gates, and ultimately, integrated optical circuits. In

addition, another application is being developed. Here

modeling is being implemented into the codes for

simulating the propagation of 50 to 100 femtosecond

pulses in semiconductor lasers.

Progress and results

The first algorithm has been developed that solves the

full-vector Maxwell equations in nonlinear dispersive

optical materials. The modeling includes the optical

carrier of a signal. Also the modeling includes the nonlinear quantum effects such as the Kerr and Raman

interactions. A finite difference method is used to

solve Maxwell's equations and also the ordinary differential equations that determine the linear and nonlinear dispersive effects.

The capability of the algorithm has been demonstrated by calculations using the 2-D vector nonlinear

Maxwell's equations for propagating and scattering

temporal and spatial solitons in material media having

linear and nonlinear instantaneous and Lorentzian

dispersive effects in the electric polarization.

Figure I shows the electric field of a propagating

optical soliton cartier pulse in a dielectric waveguide.

Notice that the pulse is not dispersing because of the

nonlinear effects. A video of these calculations shows

the optical cycles moving foward through the pulse

because the phase velocity of the carrier wave is

greater than the group velocity of the pulse. Figure 2

shows the collision of two equal-amplitude, counterpropagating solitons. After the collision, the two

pulses regain their original shapes. Figure 3 shows the

simulation of the parallel copropagation of two

inphase, equal-amplitude spatial solitons. The separation provides the basis for an all-optical switching

25
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mechanism because, without the second beam, a single

beam will travel undeflected.

Significance of the results

These calculations of propagating and scattering temporal and spatial solitons show that this algorithm has

the capability of modeling electromagnetic fields in

nonlinear optical materials. The modeling is fairly

complete in that it includes the optical carrier wave,

the full vector electromagnetic field, and the quantum

effects of the Kerr and Raman interactions. Upon further development of the geometric capabilities, this

algorithm will be able to model optical devices such as

optical switches. The resulting code can then be used

in a design mode to aid the laboratory fabrication of

such devices. Ultimately, this approach has the potential to provide 2-D and 3-D modeling capability for

millimeter scale integrated optical circuits having sub-

_n engineered inhomogeneities.

Publications resulting from study

1. Goorjian, P. M.; and Taflove, A.: Direct Time Integration of Maxwell's Equations in Nonlinear

Dispersive Media for Propagation of Femtosecond Electromagnetic Solitons. Optics Letters, vol. 17, no. 3, Feb. 1, 1992.

2. Goorjian, P. M.; Taflove, A.; Joseph, R. M.; and

Hagness, S. C.: Computational Modeling of

Femtosecond Optical Solitons from Maxwell's

Equations. IEEE J. Quantum Electronics, special issue on Ultrafast Optics and Electronics,

vol. 28, no. 10, Oct. 1992, pp. 2416-2422.

3. Goorjian, P. M.; Joseph, R. M.; and Taflove, A.:

Direct Time Integration of MaxweU's Equations in 2-D Dielectric Waveguides for Propagation and Scattering of Femtosecond

Electromagnetic Solitons. Integrated Photonics

Research Topical Meeting, Optical Society of

America and IEEE/Lasers and Electro-Optics

Society, Palm Springs, Calif., March 22-24,

1993.

4. Goorjian, P. M.; Joseph, R. M.; and Taflove, A.:

Calculations of Femtosecond Optical Solitons

from the Vector Nonlinear Maxwell's Equations, Short Wavelength V: Physics with

Intense Laser Pulses. Second Topical Meeting.

Optical Society of America, San Diego, Calif.,

March 29-31, 1993.

5. Joseph, R. M.; Goorjian, P. M.; and Taflove, A.:

Direct Time Integration of Maxwell's Equations in Two-Dimensional Dielectric Waveguides for Propagation and Scattering of

Femtosecond Electromagnetic Solitons. Optics

Letters, vol. 18, no. 7, April 1, 1993.

6. Goorjian, P. M.; Joseph, R. M.; and Taflove, A.:

Calculations of Femtosecond Temporal Solitons and Spatial Solitons Using the Vector

Maxwell's Equations, Nonlinear Guided-Wave

Phenomena. Third Topical Meeting, Optical

Society of America and IEEE/Lasers and

Electro-Optics Soc., Cambridge, England,

Sept. 19-22, 1993.

Key words

Computational nonlinear optics, All-optical switches,

Femtosecond temporal and spatial solitons

27
i:iii_

i/i!:iiii _

Tension and Compression Effects of Cell Behavior

Investigator(s)

Rosalind A. Grymes and Christine Sawyer,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Our experimental model system consists of mammalian cell cultures grown on flexible membranes in

six-chamber array. Eight of these arrays can be accommodated in a baseplate assembly connected to a

vacuum source. The vacuum draws the flexible membranes downward, creating a defined environment of

uniaxial stretch that is transduced by the membrane to

the layer of cells growing on the membrane. A solenoid provides rapid release of the vacuum to allow

fast cycling. It is possible to reliably provide maximal

stretch to this system at frequencies of 0.5 hertz. The

membranes are impermeable to liquids and gases and

are specially treated with an amino coating that permits attachment and spreading of anchoragedependent cells. Figure I is a diagram of the deformation of the membrane and the resultant stretch.

Our objectives were to:

• Evaluate the effect of mechanical stretch on

the growth of fibroblasts, studying a range of force

inputs.

• Investigate potential interactions between

growth factor response and the mechanical force

stimulus.

Rest

Vacuum

Maximum stretc_aximum stretch

Minimum stretch

Figure 1. Deformation of the flexible membrane by applied

vacuum, resulting in membrane elongation and stretch.

Adapted from Banes, et al., American Biotechnology Laboratory, May 1990, pp. 12-22.

• Observe by photomicroscopy the progress of

healing when wounds are created experimentally in

two-dimensional layers of fibroblasts; is there an effect

of added force on healing behavior?

In determining the response of normal dermal

(skin-derived) cells to various regimens of applied

mechanical stretch, we noted two significant, related

behaviors. First, cells could be successfully cultivated

over a wide range of protocols involving both static

and cyclic stretch. The cultures exhibited no observable deterioration over the course of the experiment

(up to seven days). Control cells were parallel cultures

grown on the same flexible membrane material but

backed by rigid polystyrene and not exposed to

stretch. Both the stretched cultures and controls

showed similar growth kinetics, measured by daffy

counts of actual cell numbers and by radionuclide

labeling of newly synthesized DNA. However, we

found that the behavior of stretched and control cultures became more and more similar in sequential

experiments, regardless of the applied stretch protocol.

In figure 2, the cumulative results of multiple stretch

regimens are combined. The two curves, control and

stretch, cannot be distinguished within one standard

deviation. This adaptation is not related to the applied

stretch; it is directed by adaptation of the cells to the

flexible substrate. It is a result of the dynamic interaction between the cells and the flexible membrane,

mediated by the ability of the membrane to resist

intracellular tension generated by cytoskeletal

structuresmthe internal support network that provides

structure to the cell.

Progress and results

We next evaluated the ability of fetal dermal cells to

respond to the soluble growth factor platelet-derived

growth factor (PDGF) under conditions of applied

cyclic stretch. Cell proliferation was followed as

described above, by labeling newly synthesized DNA

and counting cells. The stretch regimen used was

12.5 kPa of vacuum (translating to 20% maximal

membrane elongation) at 6.67 cycles/minute. Under

these conditions, the fetal cells demonstrated two very

different behaviors, shown in figure 3, that depended

on the application of stretch. In the mechanically active

environment, the cells demonstrated an increased

growth response, but this response was independent

of the concentration of growth factor added. In

addition, the proliferation response reached a set point

28
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18,000 Normal aged

16,000 4000 Werner's syndrome

dpm

104 cells

14,000

12,000

10,000

8000

600O

4000

2000

3500

3000

2500

2000

1500

1000

500

T

--IStretch Control Stretch Control Stretch

+ + + + +

PDGF PDGF PDGF PDGF PDGF

T

i i

ii

!

I

I

Control

+

PDGF

Figure 2. The graphic on the left shows the response of normal aged skin fibroblasts to both stretch and PDGF, applied

separately or simultaneously. The y-axis value measures amounts of radioactive thymidine incorporated into newly

synthesized DNA. The graphic on the right shows the results from two different and temporally sequential experiments on

the Werner's syndrome cells.

and did not deviate from this point over the dose

range tested (0-8 maximal units/ml). In contrast, the

control cultures exhibited a normal response to PDGF,

which rose linearly to a plateau. The half-maximal

stimulation was achieved at approximately 2 maximal

units/ml of PDGF. This value was approximately

equal to the stretch-activation setpoint. Clearly, the

cells used were capable of mounting a normal

response to the growth factor applied and the concentrations of PDGF provided were adequate for maximal

response. However, under the applied stretch regimen, these cells primarily responded to the stretch

stimulus and not to the soluble growth factor. The two

stimuli were not additive, in this case, and therefore

appear to utilize different (although perhaps not isolated) intracellular signaling systems.

Using the information obtained in our preliminary

experiments, we selected one stretch regimen and one

concentration of PDGF for our continuing work. Normal aged dermal cells were compared with dermal

cells derived from a subject with premature aging

syndrome, Werner's syndrome. This genetically

60,000 -- Normal fetal

50,000

40,000

E

0. 30,000

"O

20,000

10,000

Control

Stretched

I ! I I I

0 1 2 4 8

Units/ml 99% pure natural human PDGF

Figure 3. PDGF dose response of normal fetal dermal cells

under conditions of stretch or absence of applied stretch

(control).

i_iiiiii:_i_i!i_ilq _:!_il _

_!:_!i_i, _I __?_ , i? ,

29
acquireddiseaseofacceleratedagingischaracterized

invitroby"nonresponsiveness" toPDGF.ExperimentshadpreviouslydemonstratedthatthePDGF

receptorsonWerner'ssyndromecellswerenormalin

affinityandnumberandthatthenuclearsequences

requiredto transmitsomesecondarysignalswere

normal.It wasourintentiontostudytheabilityofthe

mechanicallyactiveenvironmenttointeractwiththe

PDGFreceptorpathwayinthesecells.Bothcelltypes,

normalandWerner'ssyndrome,wereadaptedto the

flexiblemembranesubstrateforatleasthreesequentialpassagespriortotheinitiationofthesestudies.

ThefirstWerner'ssyndromecellassaywassurprising.SixhoursafterPDGFtreatmentandsimultaneousapplicationof stretch,thesecellsdemonstrateda

proliferativeresponseto thegrowthfactoronlyunder

themechanicallystretchedcondition.In thisexperimentwewerealsoinvestigatingmanyotherparametersof cellgrowthandresponse,includingthe

productionofmessengerRNAfortheimmediatearly

genec-fosanditsdownstreamtarget,collagenase

typeI (aenzymecriticalfortissueremodelingprocesses). Onlytwochamberswerededicatedtothe

DNAsynthesistimepoint.Werepeatedthestudy,

incorporatingaprotocolthatdesignatedsixchambers

to thisanalysis,andanadditionalthreechambersto

thedirectcellcounts.Onceagain,weobservedalarge

responseto theappliedgrowthfactor,underthe

stretchedconditionsonly.Controlchamberscontinued

to demonstratethesamefailuretorespondthatis

classicallyassociatedwithWerner'ssyndromecells.

NormalagedcellsrespondtotheappliedPDGFunder

eitherthestretchedorstaticcondition.In athirdsetof

experiments, weagaindemonstratedtheunique

responseoftheWerner'ssyndromecellstoPDGFand

appliedstretch.Onceagain,however,weweresurprised.In thislaststudy,theWerner'ssyndromecells

alsorespondedtoPDGFbyproliferatinginthe

absenceofappliedstretch.Weproposethatthisgradualshiftin theabilityof thesecellstomountamitogenicresponseto thesolublegrowthfactorPDGFis

partofthespectrumofcellularadaptationtothemalleablesubstratediscussedabove.

Significance of the results

The results of these studies are shown graphically in

figure 4. In the mechanically active environment,

where the stretch stimulus was present, Werner's syndrome ceils are able to appropriately proliferate in

response to PDGF. Over time, the dynamic interaction

between the cells and their substrate is itself a powerful stimulus and results in an adaptive behavior that

rewires the cell's internal signaling pathways and

permits normal PDGF response to occur. The impact

30

10,000

8000

=o• 6000 I

X

E 4000

Q.

qD

2000

-- Aged normal • Control mean

[] Stretch mean

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0 1 2 3 4 5

Days

Figure 4. Cumulative results from multiple studies of different stretch regimens, using normal aged skin cells, demonstrate that the control and stretch cultures do not differ

significantly from each other. They lie within one standard

deviation of each other, as indicated by the shaded regions.

of tensional force balance participating in the regulation of cellular signaling has been discussed in the literature and demonstrated in isolated artificial systems.

We have discovered a novel demonstration of the

validity of these concepts. The central role of the

cytoskeleton in the perception of stretch and the cell's

response to stretch has been established, and we have

determined that force perception/response behavior

depends on an interconnected cell population of critical size. We believe that this model system will allow

further experimentation on the mechanism of intercellular communication that permits individual cells to

respond coordinately to applied environmental forces.

While pursuing another segment of our study,

observing the regrowth of cell sheets after artificial

"wounds" were created in the culture wells, we noted

that the skin cells aligned their cell bodies parallel to

the direction of applied stretch. In the circular wells,

this response translates to a radial array of cells like

the spokes of a wheel. We examined the nature of this

behavior in several ways. First, we evaluated the

impact of cell density on "orienteering." All cell strains

examined, including skin fibroblasts of different

chronological ages and corneal (eye) fibroblasts,

require a specific minimum of cell-cell contact to initiate orienteering behavior. In the fetal cells, the

requirement is particularly stringent. Sparse cell cultures fail to orient parallel to the applied stretch, and
_ ii! !!_  ̧

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_iii!!_ _i!_!_!!_! __

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i _'_ i_! i i_ I

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dense cultures distribute the stretch across multiple

cell bodies such that the perceived direction is an

apparently nonlinear complex function. The application of drugs that depolymerize the cytoskeleton affect

orienteering in a dose dependent fashion. We have

found that low doses (62.5 ng/ml) of this drug do not

seriously affect growth, but they inhibit orienteering

and cause a weakening of the cytoskeleton that can be

observed using immunofluorescence microscopy.

Publications resulting from study

1. Grymes, Rosalind A.; and Sawyer, Christine:

Studies of Senescent Cell Behavior in

Response to PDGF Under Conditions of

Varying Stress. Abstract presentation, American Society of Biochemistry and Molecular

Biology, Apr. 1993.

2. Grymes, Rosalind A.; and Sawyer, Christine: Dermal Fibroblasts in a Mechanically Active Environment. NASA-ARC Paper presented at the

American Society for Gravitational and Space

Biology, Oct. 1993.

3. Sawyer, Christine; and Grymes, Rosalind A.:

Human Dermal Fibroblasts Orient in

Response to Applied Stretch. Abstract

submitted to Western Regional Society for

Investiga tive Dermatology Meeting, Feb. 1994.

Key words

Physical forces and mammalian cells, Cell biology,

Growth factor response

31
The Deuterium Abundance in the Interstellar Medium

Investigator(s)

Michael R. Haas and Alexander G. G. M. Tielens,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Edwin F. Erickson, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Understanding the origin and evolution of the Universe is a fundamental problem in astrophysics. It is

generally accepted that the Universe formed with a

"Big Bang" at very high density and temperature. At

that point, the Universe consisted of photons and various exotic elementary particles. Upon expansion and

cool down, these particles decayed and/or combined

and simple nucleons such as hydrogen and helium

were formed. Upon further expansion, under the

influence of their own gravity, these atoms formed

stars and these stars then nucleosynthesized the heavier elements, such as C, N, O, and Fe.

The early Universe can be studied through its

relics, the 3 K background radiation, and the relative

abundances of the isotopes of H and He. Among the

latter, deuterium stands out as the most powerful

constraint because it is rapidly destroyed at high

nucleon densities. Thus, the deuterium/hydrogen

(D/H) ratio measures the time spent at high densities;

i.e., the expansion rate of the very early Universe. The

goal of this research is to infer the D/H ratio from

observations of several rotational lines of HD and H2

in gas that has only recently been heated by interstellar

shock waves.

Although observations of many different deuterated molecules have already been made, the

interpretation of these measurements is generally

uncertain because the observed species are typically

only minor reservoirs of deuterium and corrections for

the unseen deuterium are substantial and largely

unknown. This situation is contrary to that for warm

(--500 - 2000 K), dense gas that has been heated by

interstellar shocks. Here the deuterium chemistry is

dominated by neutral-neutral reactions, in particular,

D + H2 --_ H + HD. The conversion of D into HD by

this reaction is much faster than the shock cooling time

and all the deuterium is expected to be in the form of

HD. Similarly, all the hydrogen is expected to be

molecular. Since this shocked gas is warm, the emission is relatively strong, thereby presenting an excellent opportunity to probe the total gas phase deuterium abundance using observations of a single

species. Hence, the detection of these HD transitions

will yield the most direct determination of the D/H

ratio to date.

Progress and results

We proposed to use the facility Cryogenic Grating

Spectrometer (CGS) aboard the Kuiper Airborne ....

Observatory (KAO) to observe several far-infrared

transitions of HD and H2 in the Orion molecular

shock. This particular shock, which is believed to be

associated with the embedded protostar IRc2, was

chosen because it is nearby (--500 pc), has been well

studied, and is relatively well understood. The temperatures and colun_ densities of the shock-heated

gas can be inferred from observations of high-J CO,

We have completed a theoretical calculation of the

predicted line intensities for the lowest lying rotational

levels (quantum number J) of the _) = 0 vibrational

level for a two-component model with an H2 column

of 2 x 10 20 cm -2 at a temperature of 2,000 K and an H2

column of 4 x 10 21 cm -2 at 750 K. The brightest lines

are the 0-0 R(4), R(5), and R(6) transitions, which occur

at wavelengths of 28.51, 23.03, and 19.43 _tm, respectively. Fortuitously, the atmospheric transmission in

the vicinity of all three of these transitions is extremely

good at KAO altitudes (>41,000 feet). These transitions

should be detectable with the CGS, but will require

careful observations because the strong dust continuum emission from the nearby Kleinmann-Low (KL)

nebula sharply reduces the contrast in the lines.

The Si:Sb back-illuminated blocked impurity band

(BIBIB) detectors originally proposed for and funded

by this investigation are still the detectors of choice

because of their extended long wavelength coverage

(--40 _tm) and excellent sensitivity. However, these

detectors have not yet been procured because they are

still under development at the Rockwell International

Science Center and because of the time required to get

a Purchase Request for items over $25,000 through the

Ames procurement system. Preliminary discussions

with procurement representatives occurred in late

August 1992 and the initial Request for Proposal

(RFP) was finally released to industry in March 1993.

Only after receiving a response to this RFP did we

fully appreciate the tremendous development cost of

these detectors and realize that we could not support

such an activity with the available funds. A major

32
problemisthattheplatescale(13in.mm-1ofthe

currentCGSinstrument)andthediffractionlimited

beamsizesachievableontheKAOtelescope(5in.at

20_tm)areincompatiblewiththerelativelysmallpixel

size(75_tm),whichhasbecomethedefactostandard

forthe128x 128BIBIBarraysandtheirassociatedcold

multiplexers.Sincethereisnoroomin theCGSfocal

planeforthenecessaryreimagingopticsandno

chanceofindependentlyfundingtherequisitemultimilliondollardevelopmentofcustomhybridarrays,

wehavechosentoconcentrateonobtainingaonedimensionalarrayfortheCGSandtopursuefunding

foranewKAOinstrumenthatcouldtakefull advantageoftheexistingandanticipatedtwo-dimensional

arraysthatarebeingindependentlydevelopedwith

otherfunds.Tothisend,wehavenegotiatedan

arrangement with Rockwellanditsprimecontractor

fortheSi:SbBIBIBdevelopmentwherebywecan

obtainappropriatedetectormaterialatnocost.Inthis

case,theonlychargetouswill beforthepackaging

andcryogenictestingof thedesireddetectorassembly,

whichfitscomfortablywithinouravailableDDF

funding.Thefinaldetailsofthisprocurementare

presentlybeingworkedout.

Becauseof thelongdelaysin obtainingthedesired

Si:SbBIBIBdetectors,wehaveexploredotheravenues

formeetingourpresentscientificobjectives. Weare

currentlyinstallingaone-dimensional arrayofSi:As

BIBIBdetectorsintheCGS,whichareonloanfrom

Rockwell.Wehaveclonedourexistingcoldpreamplifierdesignandhavefabricateda13-channel preamplifierfor usewith thisdetectorset.Wearecurrently

scheduledtofly theSi:AsBIBIBsaboardtheKAOin

earlyNovember1993tobeginourobservationsofthe

Orionshock.WhereasthecurrentSi:AsBIBIBsare

incapableofobservingtheimportant0-0S(0)lineof

molecularhydrogenat28.2_tmorthe0-0R(4)lineof

HDat28.5_tm,bothof whichrequiretheextended

wavelengthcoverageoftheSi:SbBIBIBs,theyare

capableofobservingtheshorterwavelength(<_26_tm)

0-0R(5)andR(6)linesofHDandthe0-0S(1)lineof

H2withgoodsensitivity.However,becauseofthe

largerpixelsizeandtheone-dimensional natureof

thisarray,ourspectralresolutionandspatialcoverage

oftheshockwill belessthanoriginallyanticipated.

Nevertheless, wefeelthatthisconfigurationwill permitustodetectseveralof thebrighterHDlinesinat

leastonepositionintheOrionshock(shockedmolecularhydrogenpeak1).

OurdiscussionswithRockwellconcerningthe

anticipatedperformance, developmentcost,andphysicalformatoffuturetwo-dimensional midinfrared

detectorarrayshaspromptedustoconsiderbuildinga

newKAOinstrumentinordertomorefullyexploit

thisexcitingtechnology.Wehavedevelopedapreliminarydesignforsuchaninstrument,whichwehave

calledtheAmesInfraRedEchelleSpectrometer o

AIRES.RelativetothecurrentCGS,it will have

improvedspectralresolution(uptoafactorof 15),

slightlysmallerspatialpixels,andimagingcapability

inthecross-dispersiondirection.Thisinstnmlentwill

includeseveraloptionsforreimagingoptics,sothatit

cantakeadvantageofavarietyofdifferentarrayformatsastheybecomecommerciallyavailableandthus

obviatecostlydevelopmentofcustomarrayformats.

WearerefiningtheAIRESdesignwiththegoalof

makingairborneobservationsin lessthanthreeyears.

Publications resulting from study: None so far

Key words

Infrared detectors, Airborne astronomy, Deuterium,

Molecular hydrogen

33
Determination of Polar Stratospheric Cloud Onset Over

Antarctica Using Cloud Top Temperature Retrievals from the

NOAA Advanced Very High Resolution Radiometer

(AVHRR) Satellite Imagery

Investigator(s)

Steve Hipskind, Ames Research Center,

Moffett Field, CA 94035-1000

Kathy Pagan, San Francisco State University,

San Francisco, CA 94132

Steve Gaines, Sterling Software,

Ames Research Center,

Moffett Field, CA 94035-1000

Oswaldo Garcia and Patricia Foschi,

San Francisco State University,

San Francisco, CA 94132

Polar stratospheric clouds (PSCs) that form in the cold

stratosphere over Antarctica play a crucial role in the

destruction of ozone and lead to the formation of the

ozone hole. Although many of the chemical processes

involving PSCs and ozone depletion have been known

for years, the actual timing of the onset and duration

of PSCs and their geographic extent are not well

understood. The objectives of this study are to determine whether advanced very high resolution radiometer (AVHRR) data can be used to detect PSC temperatures in the stratosphere over Antarctica and to

differentiate them from the extremely cold Antarctic

surface temperatures. In addition, the development of

an automated PSC detection scheme will allow processing of a large volume of data in order to assemble

a climatology of PSCs.

During the last year, AVHRR imagery covering

the time period from April to October 1992 was

obtained from the Arctic and Antarctic Research Center at Scripps. Several hundred images were processed

using the Meteorological Satellite Downlink and Display System at Ames. The images were filtered and

processed automatically using FORTRAN programs

and script fries developed specifically for this project.

The minimum temperature was located in each image,

and the temperature range in which PSCs are likely to

form were highlighted. The areal extent of the PSC

temperature range was calculated using ERDAS software. This initial processing of the data showed that

temperatures within the PSC range could be detected

using AVHRR imagery.

The problem that remains is to differentiate the

imagery between the temperatures at which PSCs can

form and the cold surface temperatures present in

Antarctica. The use of surface temperature data from

the Antarctic Automatic Weather Station Data network NMC soundings, and temperature and aerosol

extinction coefficient data from the CLAES instrument

aboard the Upper Atmosphere Research Satellite

(UARS) satellite has resulted in the ability to distinguish thicker PSCs from surface or lower cloud cover

in a sampling of the imagery. These results can be

incorporated into more sophisticated PSC detection

algorithms.

AVHRR data has been shown to be useful in

detecting the optically thick PSCs, and with the use of

ancillary data, they can be distinguished from cold

surface temperatures. By building upon these initial

results, a long term climatology of PSCs can be constructed, since AVHRR provides excellent temporal

and spatial coverage of the polar regions on a daffy

basis.

Work during the second year of this project will

focus on the detection of optically thin PSCs. The radiance temperatures of these PSCs are affected by the

radiation upwelling from below, making classification

by temperature alone impossible. A preliminary

attempt using multispectral imagery to determine a

unique feature space for PSCs proved useful. Traditional multispectral analysis, textural analysis, and filters that focus on local differences will be tested. In

addition, new analyses and filters will be developed as

needed. Information from these analyses will be combined using a rule based approach to develop a classification scheme for detection of optically thin PSCs.

Initial results of this project were presented at

the HSRP/AESA annual review meeting at Virginia

Beach in June 1993. Commitments for presentation

included: the DDF poster session on November 9,

1993, at NASA Ames, a presentation in conjunction

with J. Mergenthaler, A. Roche, and J. Kumer from

Lockheed Research I_b at the AGU annual meeting in

San Francisco in December 1993, an Earth Science PreLunch seminar at NASA Ames on December 15, 1993,

a seminar at Lockheed Research Lab for the CLAES

group in the fall of 1993, and a presentation at NASA

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34
AmesBirdsof aFeatherimageanalysisgroupon

January5,1994.

Key words

Polar stratospheric clouds, AVHRR, Satellite imagery,

Remote sensing, Image analysis

35
Real-Time Automated Diagnosis System for the Ames

Research Animal Holding Facility

Investigator(s)

David L. Iverson and Stephanie Herrin,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Lilly Spirkovska, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Formal reliability analyses, such as failure modes and

effects (FMEA), fault tree, or digraph analyses, are performed on many engineered systems. These analyses

contain a wealth of information that can be used to

help build automated diagnosis systems. A significant

amount of effort can be saved by using reliability

analysis information to build a diagnostic system since

much of the knowledge engineering required for such

a system will be done by the reliability engineers while

performing the analysis.

In order to take full advantage of the information

contained in these reliability analyses, appropriate

knowledge representations and reasoning techniques

must be used. The objectives of this study were to

improve knowledge engineering and automated

monitoring and diagnosis technology by developing

general techniques for constructing automated diagnosis systems using information from reliability analysis models.

One system that has benefited from this work is

the Ames Research Animal Holding Facility (RAHF).

The RAHF is a Spacelab module that is used to house

and monitor animals in orbit so the effects of space

flight and microgravity can be studied. A detailed

Matrix FMEA reliability analysis was performed on

the RAHF by the Ames Flight Equipment Engineering

Branch (SPD). With further research into the use of

reliability analyses for automated diagnosis, the

information contained in the RAHF analysis has been

put to work for RAHF payload support personnel by

developing an automated system to help detect, identify, diagnose, and repair problems that may occur in

the RAHF system.

Progress and results

In the first year of research we devised a systematic

method for converting Matrix FMEA reliability models

into object-oriented diagnostic knowledge bases. The

structured approach of the Matrix FMEA method facilitates knowledge base construction. A diagnostic

knowledge base was built from the SPD RAHF Matrix

FMEA for use with the Fault Tree Diagnosis System

(FTDS) developed in the Ames Spacecraft Data Systems Research Branch (FIS). This knowledge base was

designed in a modular fashion and it can be updated

to accommodate different RAHF configurations.

During the second year, we developed a telemetry

monitoring system that uses rule based and model

based techniques. The system monitors RAHF telemetry in real time to detect anomalies in the RAHF systems. The telemetry monitoring and diagnosis systems

were integrated to allow immediate diagnosis of any

detected failures. Fault detection methods included in

the RAHF Matrix FMEA provided connections

between the monitoring rules and the diagnosis system. The FTDS was augmented to provide recovery

advice for diagnosed failures using information from

RAHF payload malfunction procedures manuals,

RAHF system experts, and the RAHF FMEA analysis.

The monitoring and diagnosis systems were combined with a graphical user interface that displays

RAHF telemetry parameters in an easily comprehended format. The complete Real-Time Automated

Diagnosis (RAD) system was tested with RAHF

telemetry from the SLS-1 mission and SLS-2 training

simulations. RAD was then installed in the NASA

Marshall Space Flight Center Payload Operations

Control Center and the NASA Ames SLS Telemetry

Monitoring Area for use by payload operators and

engineers during the SLS-2 mission in October 1993.

RAHF personnel made extensive use of RAD to monitor the status of two RAHFs onboard Space Shuttle

Columbia and the rodents housed in those RAHFs.

RAD will also be used for postflight analysis of

archived telemetry data.

Significance of the results

This research has produced general techniques for

using traditional reliability models for automated

diagnosis. With these techniques, an automated monitoring and diagnosis system can be produced for any

system that undergoes a Matrix FMEA analysis. This

system saves a great deal of time and expense that can

instead be devoted to knowledge acquisition and

knowledge engineering activities. Our studies have

also provided insight on how reliability analysts can

modify their analyses to further facilitate diagnostic

36
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reasoning by including information such as failure

detection methods, criticalities, and recovery

procedures.

Publications resulting from study

This work was published in the Proceedings of the

Sixth International Conference on Industrial and Engineering Applications of Artificial Intelligence and

Expert Systems by Gordon and Breach Science Publishers. The conference was held in Edinburgh,

Scotland, on June 1-4, 1993.

Key words

Monitoring and diagnosis, Matrix failure modes and

effects analysis, Reliability modeling

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37
Stratospheric Aerosol Particulates: Simulation of Their

Morphology, Physical Properties, and Chemistry

Investigator(s)

Richard L. Jaffe, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

It is believed that nitric acid-water aerosols play an

important role in the chemistry of polar stratospheric

clouds (PSC) that are responsible for the formation of

the ozone hole at polar latitudes during the early

spring. The aerosol mechanism involves the conversion of chemically inactive forms of chlorine (such as

HC1) to active forms (C12 and HOC1) on the surfaces of

micron-sized nitric acid-water droplets that comprise

the PSC. The properties and chemistry of these

aerosols are not well understood. Laboratory measurements have generally not accurately reproduced

the ambient conditions and in situ measurements are

difficult.

A new approach for studying the morphology and

properties of nitric acid-water aerosols is to use molecular simulation techniques. First the nature of the

interaction between nitric acid and water molecules is

deduced from ab initio quantum chemical calculations.

Then atomistic classical mechanics simulations of

ensembles of nitric acid and water molecules are

carried out. Both the bulk and surface structures of

these molecules can be ascertained. Finally, simulations of collisions between HC1 molecules and the

aerosol surface will be carried out to study the gassurface kinetics. From these calculations, the sticking

coefficient can be determined.

Progress and results

Progress has been slower than anticipated because of

unforeseen limitations in the commercial software

package selected for this work. During the 18-month

period of this project, potential energy functions for

nitric acid-water systems have been determined. These

include representations for both charge-neutral species

and ion pairs (NO_-I-I30+). The bulk structures of

crystalline and amorphous ensembles of charge neutral molecules and ion pairs corresponding to nitric

acid trihydrate (NAT) and nitric acid monohydrate

(NAM) have been determined. These are the two

prevalent forms of hydrated nitric acid in aqueous

solution and in ice. The NAT and NAM ensembles

consist of 125 nitric acid molecules and the appropriate

number of water molecules at densities corresponding

to experimental values (1.6-2.0 g/cm3). For _ese conditions, each ensemble occupied a cubic box of dirnen- _.....

sion 25.3/_. A computer generated drawing of a typical NAT ensemble is shown in the figure. Further studies to elucidate the phase diagram for these systems

must await the availability of a new release of the

simulation software (scheduled for January 1994).

Significance of the results

The results of these simulations will be used to help

make connections between experimental measurements on NAT films and in situ measurements of

PSCs. It is not known if the NAT-water ice particles

present in PSCs have the same properties and reactivities as the NAT films generated in laboratory experiments. Simulations can be carried out for both

conditions to bridge the gap between these two sets of

data.

Key words

Nitric acid trihydrate, Polar stratospheric clouds, Polar

ozone hole

38
Computer generated drawing of a typical NAT ensemble.

39
The Use of Molecular Fossils forIthe Interpretation of

P al e o environm ents

Investigator(s)

Linda L. Jahnke, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Elaine Munoz, Ames Research Center,

Moffett Field, CA 94035-1000

Tsegereda Embaye, San Jose State University,

San Jose, CA 95192

Objectives of the study

The most important biological influence on the evolution of this planet was the development of oxygenic

photosynthesis. This process, which evolved within a

group of photosynthetic bacteria, transformed Earth's

atmosphere from an anaerobic to an oxygen-rich one.

However, clear paleobiological evidence of the timing

of this transition and the biochemical evolution that

led to it is lacking. Recent technical advances in the

microanalysis of organic matter have made it possible

to detect residual molecules (biomarkers) in proterozoic (2.5 to 0.6 billion years) sedimentary rock

characteristic of specific groups of microorganisms.

Biomarker analysis is proving to be a powerful tool for

decoding the record of ancient biochemistry found in

the geological record; however, further information

about the biomarkers of photosynthetic organisms is

necessary to fully interpret information about the

evolution of oxygenic photosynthesis present in sedimentary rocks.

Two types of photosynthesis are carried out by

bacteria, anoxygenic and oxygenic. Anoxygenic photosynthesis is more primitive and involves conversion of

a reduced compound such as hydrogen sulfide to

elemental sulfur or sulfate. With oxygenic photosynthesis, the evolution of a more complex electron transport system allows conversion of water to molecular

oxygen. Whereas all cyanobacteria can grow by oxygenic photosynthesis, some are also able to grow by

anoxygenic photosynthesis; they are referred to as

facultative cyanobacteria. Facultative cyanobacteria

are thought to be an evolutionary model for the development of oxygen-evolving photosynthesis from the

more primitive anoxygenic types.

This study addresses the need to more fully

Understand the synthesis of a type of biomarker

molecule, the hopanoids, in photosynthetic bacteria,

and any relationship that the presence of these

biomarker molecules might have to the evolution of

oxygenic photosynthesis.

Progress and results

Initial work involved the growth of several types of

photosynthetic bacteria and development of methods

for the isolation and identification of any hopanoid

molecules present in these organisms. Four marine,

purple photosynthetic bacteria (anoxygenic types)

were grown and any isolated hopanoid identified by

gas chromatography-mass spectrometry (GC-MS). Of

the four types only one organism, Rhodospirillum salexigens, contained any appreciable amount of hopanoid,

the C32 hopanol (fig. 1), which is common to the

freshwater strains of purple photosynthetic bacteria.

The others, Rhodobacter sulfidophilus and two strains of

Rhodopseudomonas marina, contained only trace

amounts of hopanoid. Further work on the influence

of oxygen on the synthesis of hopanol in Rs. salexigens

demonstrated that only slightly less hopanol was

synthesized when cells were grown aerobically in the

dark as compared to photosynthetically in the absence

of oxygen.

Work was also initiated with several cyanobacteria

either known to or thought to be capable of anoxygenic photosynthesis. A facultative cyanobacterium

isolated from a sulfide-rich hot spring in New

Zealand, Oscillatoria amphigranulata, was obtained

from R. Castenholtz (University of Oregon). Although

this organism did contain hopanoid material, the

growth rate of this organism was deemed too slow to

be a potential candidate for anoxygenic growth experiments. Further work was, therefore, carried out to

characterize two new cyanobacterial isolates from a

sulfide-rich microbial mat found at Guerrero Negro,

Figure 1. Structure of the C32 hopanoid isolated from

marine purple photosynthetic bacteria.

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Baja California Sur, Mexico. We have found that both

cyanobacteria, a Pseudanabaena sp. and a Oscillatoria

sp., are capable of photosynthetic conversion of carbon

dioxide to cell material using either water (oxygenic)

or hydrogen sulfide (anoxygenic) as the electron

donor. Hopanoids were isolated from both organisms,

and growth rates were vigorous. The Oscillatoria

sp.was also found to be capable of anoxygenic photosynthetic growth using reduced carbon substrates as a

source of electrons and carbon (this process is referred

to as photoheterotrophy). This process allowed for

anoxygenic photosynthetic growth of this organism

without consideration of the toxic effects associated

with the use of sulfide. We found that the lipid

biomarkers characteristic of oxygenic photosynthesis

were also present in cells grown anoxygenically. Further work on the influence of sulfide on the growth of

these two cyanobacteria and the synthesis of hopanoid

molecules is anticipated.

Significance of the results

Marine ecosystems have played a major role in deposition of organic matter both in the present and in the

Proterozoic. The characterization of C32 hopanoids in

Rs. salexigens (principally a saltem organism) but not

in Rb. sulfidophilus or Rp. marina (characteristic of

marine benthic communities) demonstrates that the

purple phototrophs are not a good source of these

biomarker molecules in the latter marine environments. The marine cyanobacterial isolates from

Guerrero Negro contained considerably greater quantities of the hopane biomarkers in this study. In the

case of Rs. salexigens, the isolation of hopanoids from

cells grown under both aerobic and anaerobic conditions corroborates the theory that oxygen is not

required for synthesis of this molecule and that the

presence of hopanoids in sedimentary organic matter

should not be equated with the presence of oxygenutilizing organisms.

The initial studies to characterize the nature of the

photosynthetic potential of the Guerrero Negro isolates will provide a basis for future work, not only on

the influence of anoxygenic photosynthesis on

hopanoid and other biomarker molecules, but also on

the evolution of phototrophic bacteria and oxygenic

photosynthesis. The versatile metabolic capability of

the Oscillatoria GN sp. clearly points to the significance

of microbial mat communities and the importance of

studying the constituent organisms to gain insights for

development of evolutionary models depicting

paleoenvironments.

Publications resulting from study

Jaka_e, L. L.; and Munoz, E.: Characterization of Two

Facultatively Anoxygenic Cyanobacteria Isolated

from a Hypersaline Microbial Mat. Abstracts of the

93rd General Meeting of the American Society for

Microbiology, 1993, p. 253.

Key words

Photosynthetic bacteria, Molecular fossil

41
Flight Measured Wall Pressure Fluctuations Beneath Swept

Shock/Boundary-Layer Interactions

Investigator(s)

Steven A. Johnson,

Dryden Flight Research Facility,

Edwards, CA 93523-0273

A proposed research experiment titled "Flight Measured Wall Pressure Fluctuations Beneath Shock/

Boundary-Layer Interactions" has been initiated and

funded under the NASA Ames Director's Discretionary Fund Program. Funding for the proposed

experiment began June 7,1993.

The author and principal investigator for the

experiment is Steven A. Johnson at the NASA AmesDryden Flight Research Facility located at Edwards,

California.

The goal of the proposed study is to assess the

acoustical loads generated by a swept shock/

boundary-layer interaction in a flight environment

(free of wind tunnel turbulence) and to gain a better

understanding of the physical mechanisms involved in

their generation. Such an understanding is the first

step in any attempt to control or limit acoustic loading

on flight vehicles. Also, more fundamentally, the

interaction unsteadiness is critical in formulating

physically accurate flow models and interpreting

existing data.

Since funding was awarded last June, much has

been accomplished. The flight hardware has been

designed and fabricated. A prototype signal conditioning card has been designed and fabricated. In addition,

12 ultraminiature high response Kulite transducers

and two power supplies have been procured.

In fiscal year 1994, a complete benchtop checkout

of the integrated system is planned--including flight

hardware, power supplies, signal conditioning, and

data acquisition. After the systems operation is successfully demonstrated, a series of four high speed

flights will be carried out using the newly acquired

NASA F-15B as the carrier aircraft.

Key words

Unsteady pressures, Shock/boundary-layer

interactions, Flight research

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Pyrosensors for the Detection of Chemical Compounds in

Planetary Environments

Investigator(s)

Dan Kojiro and Thomas C. Shen,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

H. Coufal, IBM Almaden Research Center,

San Jose, CA 95120

Objectives of the study

To develop pyrosensors for determination of the possible oxidant in the Martian soil.

Progress and results

There are two approaches using the pyroelectric principle in determination of chemical compounds in

solution. In the first approach the heat generated by an

exothermal or endothermal chemical reaction and

sensed by a pyrosensor allows for the continuous

quantitative detection of some substances.

In the second approach, the sample absorbs

energy and the heat generated travels to the nearby

sensor, which is not in the path of the laser light. This

heat creates an electric signal that is measured and

translated into an analytical concentration.

We have applied the first approach and design to

construct our own pyrosensors. The sensor provides a

very stable baseline and demonstrates that hydrogen

peroxide concentration can be determined from 40 to

300 ppm with a reasonable calibration curve, as shown

in the figure. In recent collaboration with H. Coufal,

IBM Almaden Research Center, Calif., the sensor was

shown to be sensitive to 100 nJ of energy. Using this

sensor, hydrogen peroxide concentrations can be

detected as low as I ppm in a 50 _tL sample size with

300 mV signal amplitude.

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Significance of the results

A sensor with sensitivity of 100 nJ of energy was

developed. Using this sensor, hydrogen peroxide concentrations can be detected as low as I ppm in a 50-_tL

sample size with 300-mV signal amplitude.

Publications resulting from study

Shen, Thomas; and Kojiro, Dan: Pyrosensors for Analyzing Oxidants on Martian Soil. ACS Meeting,

Denver, Colo., 1993.

Key words

Pyroelectric, Pyrosensor, Hydrogen peroxide

43
Practical Evaluation of a New Method to Reduce Helicopter

Rotor Hub Loads

Investigator(s)

Sesi Kottapalli, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The objectives of this research study are

1. Design a root based torsional damper based

on analytical results.

Z Fabricate a root torsional damper or set of

dampers with parametric variations in damping.

3. Bench test the root torsional damper to obtain

data to substantiate the payoff of this approach.

These proposed objectives form a risk reduction

program, the culmination of which would be to draw

up plans for a full-scale wind tunnel test. The wind

tunnel test is not a part of the current proposal. However, subsequent to a successful bench test, the followon activity will fall outside of that supported by the

Director's Discretionary Fund.

Progress and results

It is analytically predicted that for the helicopter considered (S-76), rotor hub loads will be uniformly

reduced in all three directions simultaneously by the

application of blade root torsional damping, as shown

in the figure.

Significance of the results

The analytical results are very encouraging. The next

step will be to initiate design of the root torsional

damper and take preparatory steps toward its

fabrication.

Publications resulting from study

Kottapalli, S.: Blade Root Torsional Dampers to

Reduce Hub Loads. AIAA 33rd Structures, Structural Dynamics and Materials (SDM) Conference,

Dallas, Tex., AIAA Paper 92-2449, April 1992.

Key words

Blade root torsional damping, Rotor hub loads, Helicopter, Rotorcraft vibration

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44
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Stanford-NASA Ames Cooperative Program in Global

Change

Investigator(s)

James G. Lawless and Philip B. Russell,

Ames Research Center,

Moffett Field, CA 94035-1000

Gary Ernst, Stanford University,

Stanford, CA 94305

Other personnel involved

Marc L. Imhoff, Pamela Matson,

David DesMarais, Gregory H. Rau,

Robert Chatfield, John Vastano,

Thomas A. Blake, Charles Chackerian, Jr., and

James R. Podolske, Ames Research Center,

Moffett Field, CA 94035-1000

Carolyn Malmstrom, Harold Mooney,

Manuel Lerdau, Peter M. Vitousek,

Margaret Bac, James C. Ingle, Lilliana Borceau,

Joseph Oliger, Michael D. Di Rosa,

Ron Hanson, Rachel Freifelder, and

David U. Hooper, Stanford University,

Stanford, CA 94305

Objectives of the study

The purpose of the Stanford-NASA Ames Cooperative Program in Global Change is to bring together

the unique skills and facilities available at

Stanford and Ames to answer key questions on the

functioning of the Earth's atmosphere and ecosystems, especially as impacted by human activities.

Most of the DDF funds have been used to support a

variety of research tasks carried out by students

under the joint advisorship of Stanford and Ames

scientists. The remainder of the funds helped support a joint seminar series conducted at Stanford and

Ames.

A subsidiary objective was to identify proposal

opportunities through which continued funding

could be obtained for the Stanford-Ames Program or

for joint research tasks.

Progress and results

The following research tasks were funded:

• Surface coatings, varnishes, and subsoil

structures in deserts as indicators of global climate

change.

• Numerical flow simulation study for

inflight atmospheric sampling measurements.

• Influence of temperature on soil carbon pools.

• Remote estimation of vegetation biomass

using airborne synthetic aperture radar (AIRSAR).

• Regional CO2 flux in Hawaiian ecosystems:

1958-1986.

• Ecosystem-level controls on the emissions of

nonmethane hydrocarbons (NMHC) from vegetation.

• Molecular and isotopic characteristics of

ocean carbon: implications for global variability of

atmospheric and oceanic CO2.

• A one-box chemical model for trace species

in the atmosphere.

• Prototype development for an ultrasensitive

OH detector.

• Grass invasions, deforestation, and climate

change in the seasonally dry tropics.

• The effects of plant functional group diversity on nutrient cycling in a California serpentine

grassland.

Several of these tasks are complete and have

resulted in Ph.D. theses (see Publications, below).

Others are still in progress, to be completed in FY94

using the funding in Joint Research Interchange

NCA2-768. This work will be described in the Joint

Research Interchange (JRI) Final Report, which is

due December 1994.

The seminar series was used both to bring a

number of distinguished speakers to Stanford and

Ames and to provide an opportunity for Stanford

and Ames researchers to inform the combined

Stanford/Ames community of their research.

Significance of the results

The results of the above research tasks, some of

which are still in progress, are diverse. However,

they all address the factors that control the biogeochemical cycling of carbon, nitrogen, and other elements in terrestrial and marine ecosystems and the

atmosphere, and the impact of human activities on

them. Improved understanding of this cycling is key

to advancing our ability to predict how human

activities and natural processes will interact to

determine future climate changes and the ability of

human civilization to adapt to this change.

Initially it was hoped that a source of funds

could be found to block-fund continued operations of

the Stanford-NASA Ames program. Although such

a source has not been identified (and hence a

45
block-fundingproposalwasnotwritten),manyuseful collaborationsweredeveloped,andtheyare

expectedto leadto proposalstargetedat specific

researchtasksin responseto futuresolicitations

(e.g.,NASAResearchAnnouncements).

Publications resulting from study

Bac, Margaret: Molecular and Isotopic Characteristics of Oceanic Carbon: Implications for Global

Variability of Atmospheric and Oceanic CO2.

Ph.D. Thesis, Stanford University, in progress.

Borceau, Lilliana: The Application of DAE Solvers

for Advanced Atmospheric Chemistry Modeling.

M.S. Thesis, Stanford University, 1993.

DiRosa, Michael D.: Development of an Ultrasensitive OH Detector. Ph.D. Thesis, Stanford University, in progress.

Freifelder, Rachel: Microclimate Change and Fire

Following Forest Grass Conversion in Seasonal

Dry Tropical Woodland. M.S. Thesis, Stanford

University, 1993.

Hooper, David U.; and Peter M. Vitousek: Effects of

Plant Functional Group Diversity on Nutrient

Cycling in a California Serpentine Grassland.

Bulletin of the Ecological Society of America.

Supplement, vol. 74.2, 1992, p. 280.

Imhoff, Marc L.: Remote Estimation of Vegetation

Biomass Using AIRSAR. Ph.D. Thesis, Stanford

University, 1993.

Lerdau, Manuel; Litvak, M.; and Monson, R.: Plant

Chemical Defense: Monoterpenes and a GrowthDifferentiation Balance Hypothesis. Trends in

Ecology and Evolution, vol. 9, no. 2, Feb. 1994.

Lerdau, Manuel; Dilts, S.; Allwine, E.;

Westberg, H.; and Lamb, B.: Monoterpene

Emissions from Ponderosa Pine. J. Geophys. Res.,

in press.

Lerdau, Manuel; and Penuelas, J.: Los Monoterpenos

(in Spanish). Mundo Cientifico, vol. 13, 1993,

pp. 61-64.

Lerdau, Manuel: Ecological Controls Over Monoterpene Emissions in Conifers. Ph.D. Thesis,

Department of Biological Sciences, Stanford University, 1993.

Lerdau, Manuel: Contributed paper on Non-methane

Hydrocarbon Emissions Controls in Conifers. First

IGAC Scientific Conference. BiosphereAtmosphere Interactions, Eilat, Israel, Apr. 1993.

Lerdau, Manuel: Contributed paper on Ecosystem

and Physiological Controls Over Biogenic Nonmethane Hydrocarbon Emissions, Ecological Society of America, Annual Meeting, Madison, Wis.,

Aug. 1993.

Townsend, Alan R.: Influence of Temperature on Soil

Carbon Pools. Ph.D. Thesis, Stanford University,

1993.

Windeler, Don: Spectral Mineral Mapping of Scarns

and Hornfelses of the Yerrington District,

Nevada, Using Airborne Muitispectral Imagery.

M.S. Thesis, Stanford University, 1993.

Key words

Global change, Biogeochemical cycles, Atmosphere,

Biosphere interactions

46
The Study of Ozone Depletion Chemistry Using Ab Initio

Quantum Mechanical Methods

Investigator

Timothy J. Lee, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Julia E. Rice, IBM Almaden Research Center,

San Jose, CA 95120

Celeste M. Rohlfing, Sandia National Laboratory,

Livermore, CA 94551

Alistair P. Rendell, Daresbury Laboratory,

Warrington, England

Objectives of the study

Extensive documentation of the destruction of the

ozone layer, especially over the Antarctic, has been

obtained over the past 16 years. Much has been

learned about the mechanisms involved in the formation of the Antarctic ozone hole, and yet there remains

considerable chemistry of chlorine, fluorine, bromine

and nitrogen oxides that is not understood. Until

recently, ab initio quantum chemistry has contributed

little to the understanding of atmospheric chemistry.

To a large extent, this is because low-level ab initio

quantum mechanical methods are not very reliable for

molecules that contain several electronegative atoms

bonded together. However, in the last 5 to 8 years considerable progress has been made in the development

of highly accurate and much less expensive methods.

The objectives of this study were twofold. First, we

proposed to study the chemical reactions involved in

ozone depletion with special emphasis on the chemistry that takes place in the Antarctic ozone hole. Initially, chlorine oxides of chemical formulas C1202 and

(3203 were targeted, but other important and potentially important C1 reservoir species, such as C1OOH,

have also been investigated. The second objective was

to demonstrate that the newly developed high-level

ab initio methods are capable of yielding very accurate

results for molecules composed of several electronegative atoms bonded together, and therefore are capable

of providing important understanding and data in the

study of atmospheric chemistry. An initial high-level

ab initio study of three isomers of C1202 was completed in the first year of this project, and the results of

this investigation demonstrated beyond doubt that the

newly developed ab initio methods are capable of

attaining the very high accuracy required for the study

of molecules that are of atmospheric interest. Therefore, the second year of this DDF project has focused

on the study of important chemical species and chemical reactions taking place in the formation of the ozone

holes. One example is the protonation reaction of

chlorine nitrate (C1ONO2), which is thought to be a

possible mechanism for elimination of C1ONO2 by

heterogeneous reaction on the surfaces of polar stratospheric clouds (PSCs).

H + + C1ONO2 --_ CIONO2 H+ (1)

As we had previously studied the protonation

reactions of HONO2 and CH30NO2, the results of

which suggest the importance of reaction (1), the

thermochemistry of reaction (1) was studied. In addition, the structures, vibrational spectra, and thermochemical stability of other chlorine oxides have also

been investigated.

Progress and results

The study of the thermochemistry of reaction

(1) showed that indeed the most stable form of protonated chlorine nitrate is a complex between NO_ and

HOC1, demonstrating how C1ONO2 may be depleted

in the Antarctic ozone hole. That is, C1ONO2 will react

on the surface of PSCs via a proton catalyzed mechanism. Formation of the HOC1... NO_ complex is

quickly followed by reaction of NO_ with the

companion anion, possibly OH- (forming HNO3,

which then remains adsorbed to the PSC and is later

transported out of the stratosphere when the PSC

"fails") or NO_ (forming N205, which readily reacts

with H20 to form HNO3, etc .... ). The ab initio study

also provided explanations for why nitric acid/ice

compositions that are high in nitric acid are less reactive toward C1ONO2 (the proton affinity of HNO3 is

larger than that of C1ONO2, and therefore the protons

are less accessible to C1ONO2), and why elevated concentrations of HOC1 are observed in the Antarctic

ozone hole (formation of the complex leads to some

HOC1 escaping back to the gas phase). Hence, our

computational study together with experimental studies performed by Professor Mitchio Okamura at the

California Institute of Technology have provided

convincing evidence of the importance of the proton

catalyzed mechanism, along with a detailed description of the specific mechanism.

We have also been concerned with the identification of molecules that act as C1 reservoir species in the

47
Antarcticnighttime,aswellasin otherstratospheric

environmentsin whichradiationfromtheSunisfiltered(suchasatcertainlatitudes).Onepossible

speciesthathasbeenidentifiedisC1OOH.The

abinitiostudyonthisspecieshowedthatit isthermallyquitestableto simpledissociationpathways,i.e.,

C1OOH_ C10+OH+AE 2 (2)

C1OOH --_ C10 + OH + AE 3 (3)

C1OOH --_ C10 + OH + AE4 (4)

with AE2 and AE3 determined to be 33.4 and

31.4 kcal/mol, respectively. As there is no experimental information available for C1OOH, its molecular

structure and vibrational spectrum were also determined in order to aid in laboratory identification. Note

that the reverse of reactions (2) and (3) serve as "ozone

depletion termination steps." Given the concentrations

of C1 and OOH in the Antarctic ozone hole during the

springtime, when ozone depletion is actively taking

place, it seems likely that the concentration of C1OOH

will become high during the periods of reduced radiation from the Sun. Concentrations of C10 will also be

high, but the concentration of OH is generally considered to be much lower and so the reverse of reaction

(2) may not be as important. Nonetheless, it seems

evident that C1OOH will readily form, and it is therefore important to determine the possible photodissociation of C1OOH. This study is in progress.

We have also identified two low-lying isomers of

Cl203, which may be viewed as arising from the two

lowest energy structures of C1202 by replacing a terminal C1 atom with a C10 group. These two isomers

may be written as C1OOOC1 and C1OC102. Given that

the most likely stratospheric reactants for formation of

(2203 are C10 + OC10, it would seem that the

C1OC102 isomer is probably of more interest in atmospheric chemistry. Note that formation of C1OC102 is

also an "ozone depletion termination step."

The molecular structure, vibrational spectrum and

thermodynamic stability of other chlorine oxides, such

as C1NO, CINO2, and cis- and trans-C1ONO have also

been investigated in order to fill gaps in the experimental data, to resolve some discrepancies, or in some

cases to correct erroneous interpretations of experimental data.

Significance of the results

The investigation of the protonation reaction of chlorine nitrate has produced a detailed description of the

most likely mechanism for the depletion of C1ONO2 in

the Antarctic ozone hole and has provided explanations for the increased concentrations of gas phase

HOC1 and the reduced reactivity for HNO3/ice compositions containing high concentrations of HNO3.

The C1OOH study has shown that C1OOH is indeed

thermally quite stable and that it is likely to be present

in the stratosphere as a C1 reservoir species, particularly in the Antarctic and Arctic nighttimes, where it

could possibly be a major C1 reservoir species due to

its formation from "ozone depletion termination reactions." These studies have certainly enhanced our

understanding of atmospheric chemistry, and whereas

it may be some time before we attain a complete

understanding of the Earth's atmospheric chemistry, it

is clear that computational chemistry, because of its

relatively low cost and suitability for the study of

unstable species (for which laboratory studies are

often very dangerous if not impossible), has much to

offer.

Again, the most significant conclusion from these

studies is that ab initio quantum mechanical methods

have clearly been shown to yield very accurate structures, vibrational spectra, and thermodynamic information for molecules composed of several

electronegative atoms the type of molecule that is

most prevalent in the upper atmosphere. The results

thus far demonstrate that the study of atmospheric

chemistry through the use of quantum mechanical

methods is very informative and a useful complement

to experimental studies.

Publications resulting from study: First year

1. Lee, T. J.; and Rice, J. E.: FONO: A Difficult Case

for Theory and Experiment. J. Chem. Phys.,

vol. 97, 1992, p. 4223.

2. Lee, T. J.; Rohlfing, C. M.; and Rice, J. E.: An

Extensive Ab Initio Study of the Structures,

Vibrational Spectra, Quadratic Force Fields

and Relative Energetics of Three Isomers of

C1202. J. Chem. Phys., vol. 97, 1992, p. 6593.

Publications resulting from study: Second year

1. Lee, T. J.; and Rice, J. E.: Ab Initio Study of the

Chlorine Nitrate Protonation Reaction: Implications for Loss of C1ONO2 in the Stratosphere. J. Chem. Phys., vol. 97, 1993, p. 6637.

2. Lee, T. J.; and Rendell, A. P.: Ab Initio Characterization of C1OOH: Implications for Atmospheric Chemistry. J. Chem. Phys., vol. 97,

1993, p. 6999.

3. Lee, T. J.: A Coupled-Cluster Study of XNO

(X = H, F, C1): An Investigation of Weak X-N

Singl e Bonds. J. Chem. Phys., in press.

48
4. Lee,T.J.:AbInitioCharacterizationofC1NO2,cisC1ONOandtrans-C1ONO. J.Phys.Chem.,in

press.

5. Lee,T.J.:A Coupled-ClusterStudyofHNO2and

FNO2.Chem.Phys.Letters,inpress.

Key words

Atmospheric chemistry, Chlorine oxides, Chlorine

nitrate

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49
Surface Shear Stress Measurement Using Liquid Crystal

Polymers

Investigator(s)

B. G. McLachlan and J. H. Bell,

Ames Research Center,

Moffett Field, CA 94035-1000

M. L. Brandes and M. Gouterman,

University of Washington, Seattle, WA 98195

Objectives of the study

Assess the feasibility of using liquid crystal polymer

(LCP) film coatings for surface shear stress measurement in aerodynamic testing.

Progress and results

1. A prototype benchtop flow chamber was

designed and constructed to evaluate coating response

to shear stress.

Z The study demonstrated quantitative birefringent response of LCP coatings to aerodynamic shear

stress.

3. Thermal noise of the imaging array (CCD sensor) was identified as a significant problem in measurement apparatus.

4. A number of trial LCP coatings were produced and tested.

Significance of the results

The feasibility of using the birefringent response of

LCPs as the mechanism to measure aerodynamic shear

stress fields was demonstrated. The significance of our

LCP approach is that it does not suffer the drawbacks

of the present shear stress field measurement methods

(oil film interferometry and low mass liquid crystals)

and has other advantages in comparison to them.

Publications resulting from study: None so far

Key words

Aeronautical sensor, Aerodynamic shear stress measurement, Liquid crystal polymer

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Investigations of Supersonic Combustion Using Unique

NASA Ames Facilities

Investigator(s)

Gene P. Menees, Ames Research Center,

Moffett Field, CA 94035-1000

Jean-Luc Cambier and Henry G. Adelman,

Thermosciences Institute, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

To demonstrate how some unique Ames experimental

facilities, combined with new, state-of-the-art computational capabilities, can be used to investigate some

key problems in supersonic combustion and hypersonic propulsion. The approach is therefore composed

of several components. An array of codes will be used

to help analyze various aspects of the flow. Notably, a

new code for the simulation of nonequilibrium arc-jet

flows will be developed and validated. It will be used

in particular to predict the flow features in the Direct

Connect Arc-Jet Facility (DCAF) in order to correctly

estimate the contamination and nonequilibrium effects

during the flow expansion. It will also be coupled to a

radiation code, which analyzes the molecular and

atomic emission and absorption features, along a line

of sight. This method will allow us to examine the

potential of various nonintrusive diagnostic methods.

The proposed work also includes conceptual studies of

propulsion experiments to be conducted in the DCAF.

These proposed experiments will aim at answering

some key questions in supersonic mixing and combustion, and will investigate new propulsive concepts.

Engineering analyses, experiment design, test plan,

and preliminary cost estimates will be performed.

Progress and results

The first objective was to obtain an accurate, reliable

computational fluid dynamics (CFD) capability for the

simulation of arc-jet flows. Preliminary analysis of

existing codes showed some important deficiencies in

the capabilities, the numerical methods, or the modeling assumptions. For example, existing codes assume

the same value of temperature for vibrational and electronic excitation modes, equal to the temperature of

free electronics. This assumption is not necessarily

valid, and the validity of it depends on the density of

free electrons. Additionally, there is no accounting for

radioactive recombinations, nor the energy loss

through volumetric emission. Finally, we need to

develop a code with the capability to model all aspects

of the arc-jet flow, including the high-temperature arc

region. We can then interface with a combustion code

for the modeling of the experiment itself. Therefore,

new codes have been written to accurately model all

aspects of the arc-jet flow. The principal component is

a nonequilibrium plasma code named Mahler, which

uses a detailed thermochemical model of the plasma.

Notably, each electronic state can be convected separately, allowing for non-Boltzmann distributions of

excited states. This feature is important in expanding

flows. The coupling between chemistry and other excitation modes is made in a completely consistent way:

for example, the average vibrational energy removed

during dissociation is allowed to vary with both translational and vibrational temperature, and is related to

the energy replaced during recombination through the

detailed balance principle. This unique model allows

for the chemical processes alone to restore thermal as

well as chemical equilibrium. This important physical

characteristic is not possible with previous models

used by other researchers. Other codes are being

developed to focus on other aspects of the arc-jet flow,

or to provide more approximate but more efficient

simulations. For example, another version treats the

plasma as a two-fluid model and could be used for the

simulation of the arc itself.

The Mozart combustion code is being upgraded to

include a generalized grid embedding technique and a

two-equation turbulence model, which will allow us to

model newly proposed fuel injector designs, principally the Spiralling Struts and their complex geometries. In preparation for these studies, a simulation of

the flow field, from the nozzle throat to the injectors,

has been completed. Boundary layer thickness and

heat transfer to the combustor walls have been

predicted.

Significance of the results

The progress made in modeling of nonequilibrum

phenomena will allow us to model the complete arc-jet

facility with great accuracy, from the arc region to the

nozzle expansion and the combustion experiment. It

will also allow us to estimate precisely the effects due

to thermal and chemical nonequilibrium on hypersonic combustion flows.

51
Publicationsresulting from study

Cambier, J-L.; and Moreau, S.: Numerical Simulation

of a Molecular Plasma In A Collisional-Radiative

Nonequilibrum. 24th AIAA Plasma Dynamics

Conference, Orlando, Fla., July 1993. AIAA

Paper 93-1985.

Cambier, J-L.; and Moreau, S.: Validation of a TVD

Plasma Code with Collisional-Radiative

Nonequilibrium. 25th AIAA Plasma Dynamics

Conference, Colorado Springs, Colo., June 1994.

Key words

Arc-jet, Supersonic combustion

52
Mixing, Combustion, and Thrust Enhancement by a Pulsed

Detonation Wave Augmentor

Investigator(s)

Gene P. Menees, Ames Research Center,

Moffett Field, CA 94035-1000

Jean-Luc Cambier and Henry G. Adelman,

Thermosciences Institute, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

To investigate the use of unsteady waves in a supersonic combustor (scramjet) in order to enhance the

mixing and combustion rates. In this concept, blast

waves are produced at the end of small detonation

tubes embedded in the combustor wails, and they

propagate into the main combustor stream. The interaction between the strong pressure waves and the mixhag layer stimulates the formation of mixing vortices,

while shock heating of the mixture allows for very

rapid combustion. The detonation tubes are rapidly

cycled and triggered in sequence. The concept of a

Pulsed Detonation Wave Augrnentor (PDWA) can

lead to significant improvements in scramjet engine

performance.

Progress and results

Preliminary computational fluid dynamics (CFD) studies of various generic engine configurations were performed in order to estimate the effectiveness of the

concept and to identify the key elements for future

parametric studies. The numerical simulations were

performed using a two-dimensional, time-accurate

Navier-Stokes code, coupled to the full chemical

kinetics of hydrogen-air combustion. Two

configurations were studied. The first one, named

"transverse coupling," used a detonation tube with

small holes on the side. Blast waves can be generated

at these holes from the high pressure region behind

the detonation wave. The emitted blast waves then

interact with a free mixing layer in a supersonic

combustor. This configuration was effective for strong

blast waves, but it suffered from relatively large

stagnation pressure losses. The problem stems from

the presence of high pressure sources at fixed

locations, which had the effect of generating strong

oblique shocks within the supersonic combustor (see

fig. 1). Reducing the overpressure in the detonation

tube reduced these losses, but it also reduced the

effectiveness of the blast waves in increasing the

mixing and combustion.

The second configuration, "axial coupling," simply

used a shorter tube, and the blast wave was generated

at its exit, from the decay of the detonation wave.

After diffraction at the tube exit, the wave could then

interact with a free mixing layer. The advantage of this

concept is that most of the high pressure flow is

directed downstream in the combustor. As expected,

the stagnation pressure losses are now much smaller.

The efficiency of this device at promoting mixing and

combustion is also observed to be very good. As the

blast wave diffracts at the tube exit, the mixing layer is

compressed and heated by the passage of the wave.

This reaction triggers an immediate combustion of the

fuel in that region. The fuel layer is then pushed by the

blast wave, and starts to roll up. This process creates

regions of large vorticity as well as a stretching of the

mixing interface, both being beneficial features for

mixing enhancement. Further heating and ignition

takes place at various locations during the interaction

between this single pulse and the mixing layer. These

features can be seen in figure 2, which shows a time

sequence of the temperature contours (up to

275 microseconds from the time at which the detonation wave reaches the tube end). It is important to

notice that there is no strong, steady oblique shock

generated by the pulse and that the fuel layer is considerably altered by the passage of the shock structure.

A detailed examination of the flow also revealed

an interesting phenomenon. As the shock moves

through the fuel layer, interface instabilities are seen to

develop. These are the Richtmyer-Meshkov instabilities, which are known to promote mixing between

driver and driven gas, for example, during shock tunnel operation. The same effect can be put to good use

here, since it is our goal to accelerate the mixing process. This effect occurs for unsteady shock waves only,

and for waves propagating normal to the fuel-air

interface. This effect can be contrasted with the more

conventional baroclinic effect, which operates only

when pressure and density are misaligned. Another

feature that was observed in both configurations

studied was the existence of a transmitted shock

within the fuel layer, which could propagate faster

than all other flow structures. This feature is possible

because of the very high speed of sound in the pure

fuel (H2). This feature may be of interest in other

applications, notably external combustion.

53
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Figure 1. Shock structure for the PDWA in transverse coupling mode. Blast waves generated at the side vents in the

detonation tube interact with the free mixing layer in the supersonic combustor. A complex pattern of strong shocks is

generated as a result.

54
Figure 2. Time sequence of temperature contours. PDWA operation. Rapid combustion is seen in frame 2 (75 microseconds).

Fuel layer is seen to rollup and breakup. Strong mixing vortices are generated.

55
Significance of the results

The PDWA concept was designed with the following

goals: enhancement of the mixing, acceleration of the

combustion, and thrust increase, with minimal losses

and high efficiency. The preliminary computational

results show that these goals can be simultaneously

achieved with careful choice of thedesign configuration. The thrust enhancement comes from the detonation wave itself, which is a very efficient propulsive

mechanism (near-constant volume combustion). The

detonation can be directly initiated, in the appropriate

mixture, with very small electrical power requirements. Rapid cycling of the tube is possible, and it is

made more effective by a series of tubes fired in

sequence. The mixing and combustion enhancements

are clearly demonstrated by the numerical

simulations. It is clear that the concept has enormous

potential, and it should be verified experimentally, as

well as theoretically, through a progressive series of

tests and more detailed numerical simulations.

Variations of the PDWA concept can also be

considered and applied, for example, in stimulated

external combustion or nozzle combustion. If

successful, the PDWA concept can lead to significant

improvements in hypersonic air-breathing engine

performance.

Publication resulting from study

Cambier, J-L., et al.: Numerical Simulations of a Pulsed

Detonation Wave Augmentation Device. 29th

AIAA Joint Propulsion Conference, Monterey, .....

Calif., AIAA Paper 93-1985, June 1993.

Key words

Scramjet, Mixing enhancement, Detonation,

Thrust augmentation

ii:

56
Ablating Surface Heat Transfer Estimation for Flight

Application

Investigator(s)

Greg Noffz and Mike Bowman,

Dryden Flight Research Facility,

Edwards, CA 93523-0273

Objectives of the study

Flight vehicles can be instrumented with subsurface

thermocouples such that inverse analysis procedures

can yield useful estimates of surface heat transfer. If

the vehicle has an ablating heat shield, however, temperature time histories from subsurface thermocouples

no longer provide enough information to estimate heat

flux at the surface. This situation arises because the

problem geometry is changing and thermal energy is

leaving the surface with the ablation products. An

ablator recession rate is now required to estimate heat

transfer to the surface.

This research effort has concentrated on developing a capacitive gage concept in which the ablator has

a dielectric effect on the capacitor's fringe region. Relying on a capacitor's fringe region enables the gage to

be flush mounted in the vehicle's permanent structure

and not intrude into the ablative heat shield applied

over it. Our goal is to develop this concept into a

gage(s) capable of measuring the recession of low

temperature ablators that are applied in thin

(0.020-0.060 in.) layers.

The work has been concentrated in two main

tasks. First, candidate gages were fabricated and tested

with each successive generation becoming more

sophisticated in its packaging. Second, different gage

geometries were modeled using finite elements.

Progress and results

A method of measuring the small changes in capacitance, which involves making the gage part of a series

resistive-inductive-capacitive (RLC) "load" at the end

of a waveguide, has been tested. Radio frequency (RF)

energy is sent to the RLC circuit via the waveguide

from a signal generator. If the load is excited at its resonant frequency, all the energy from the source is dissipated in the load's resistance. If the load's resonant

frequency now changes (say, due to a change in capacitance), some of the RF energy will be reflected back

toward the source. This reflected energy is detected by

a reflection coeffecient bridge (RCB), which outputs a

dc signal proportional to the impedance mismatch at

the load.

The gage geometries were produced from circuit

board material using common etching techniques. The

inductor and resistor, together with the gage form the

RLC termination, were attached to the backside of the

circuit board. Preliminary tests were performed with

this arrangement but the need for a shielded, mechanically stable termination was obvious. This led to the

development of the second generation packaging system shown in figure 1. The gage, etched from circuit

board material as before, has a resistor and toroidal

inductor soldered to its backside. A Delrin chassis

supports this assembly and the entire system is surrounded by a brass casing. The RLC termination is

connected to a coaxial cable through a modified male

bayonent navy connector (BNC). The entire assembly

is potted with room temperature vulcanizing (RTV).

The brass casing is electrically connected to the shield

side of the coaxial cable. As hoped for, only the face of

the gage is sensitive to its surroundings.

Nine candidate designs in both first and second

generation packages have been lab tested using the

waveguide/RCB arrangement. Delrin shims of various

thicknesses were used to simulate the ablator.

Although manufacturing problems (warping and

tapering) with the shims have prevented us from

obtaining true "Delrin calibrations" for the candidate

gages, remarkable consistency between different gages

of the same geometry was observed. One of the better

examples is shown in figure 2. RCB output versus

Delrin shim thickness is shown for two gages (serial

numbers 001 and 005), both with conductor and gap

widths of 0.020 in. Shim imperfections are detected by

both gages. Gage sensitivity drops off for shims

greater than about 0.050 in. The RCB arrangement

gives a large percentage change in mV output for the

range of interest and is insensitive to cable/hardware

arrangement and local RF energy. Qualitative tests of

the gage's sensitivity to temperature gave encouraging

results.

Various gage geometries were modeled using a

commercially available finite element code. The models are two-dimensional and intended to illustrate the

effect of conductor width and spacing on gage sensitivity. The PC board and uncharged "ground plane"

are included. The infinite domain of the physical problem is simulated with the finite domain of the model

with the use of absorbing boundary conditions. Elements above the conductors can be assigned the permittivity either of ablator or of air. Ablator thicknesses

57
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Figure 1. Second generation packaging system.

of 0.0, 0.010, 0.020, 0.030, and 0.050 in. are simulated

for each gage geometry. Figure 3 shows the results

from two gage geometries, one with a conductor width

of 0.005 in. and a gap width of 0.020 in. (5.20) and one

with a conductor width of 0.010 in. and a gap width of

0.020 in. (10.20). As expected, the largest change in

gage capacitance takes place when the last 0.010 in. of

ablator is removed. In these two cases, varying ablator

thickness above 0.030 in. does not change gage capacitance much, whereas in the intermediate range

(0.010 in.-0.030 in.) the 10.20 geometry is more sensitive. Generally, the geometries with wider conductor

widths and gaps tended to be more sensitive at thicker

ablator thicknesses than those geometries with thinner

conductor widths and gaps. This trend was also

observed in lab tests.

A multiplexing system incorporating an RF switch

that will allow four gages to be operated with a single

signal generator and RCB is being developed.

58
2°°I

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150 -

E

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0

m

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001

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.02 .04 .06 .08 .1

Shim thickness (in.)

Figure 2. RCB output versus shim thickness.

Significance of the results

Finite element model (FEM) analysis confirms some of

the observations made during lab tests and a third

generation gage geometry is being produced, incorporating lessons learned. The packaging system developed provides mechanical stability and shielding.

Results so far indicate that this gage concept has the

ability to measure thickness changes in the range and

to the resolution require& Hardware power and size

requirements do not exceed what would be available

on a flight vehicle. Additional applications possibly

include measuring the sublimation rate of surface

flow-vis chemicals like napthalene and wing ice

detection.

Publications resulting from study: None so far

Key words

Ablation measurement, Thin film measurement

°

59
i iiii _i_ii

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•Slope = .........................................................................................

87.34 pF/cm in.

.

0 .01 .02 .03 .04 .05

Ablator thickness (in.)

Figure 3. Gage sensitivity for 5.20 and 10.20 geometries.

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Crew Decision Making in Aerospace Environments:

A Taxonomy of.Decision Structures

Investigator(s)

Judith Orasanu, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Rick Tarrel, San Jose State University Foundation,

San Jose, CA 95192

Ute Fischer, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Of fatal air transport accidents between 1983-1987,

47% involved failures of crew decision making, planning, or communication (National Transportation

Safety Board (NTSB), 1991). Scientific research has not

provided an adequate basis for training or aiding

crews to make decisions in complex dynamic environments such as aviation or space. Before we can

hope to improve the safety of aerospace operations, it

is essential to understand the nature of decision tasks

crews actually face and how they respond to them.

The objectives of this project are to:

. • Develop a taxonomy of the kinds of decisions

crews face in aerospace environments

• Determine the cognitive demands posed by various problem conditions

• Identify vulnerable areas and types of errors

crews are likely to make

• Describe effective decision making strategies

• Determine the costs and benefits of various

decision strategies.

Progress and results

Three integrated efforts have been initiated this year:

1. Incident and accident reports (Aviation Safety

Reporting System (ASRS), NTSB) have been analyzed

to identify decision types, which served as input for

building a decision taxonomy.

Z Crew performance in full-mission simulators

has been analyzed to identify more and less effective

decision making strategies.

3. NTSB accident reports have been analyzed to

develop hypotheses about types and sources of crew

decision errors.

Efforts to date have yielded the following products and preliminary conclusions:

1. Two primary factors define the complexity

and difficulty of cockpit decisions: degree of ambiguity in problem specification and degree to which

responses are prescribed. Time pressure and risk level

function as amplifiers (fig. 1).

Z Different types of operational events make

different cognitive demands on the decision maker;

different strategies are appropriate to different types of

decisions (fig. 2).

3. More effective crews are flexible in their application of decision strategies; they know what information is important; their decisions are sensitive to

constraints; they have longer planning horizons and

actively manage their "windows of opportunity."

4. Errors frequently result from poor situational

awareness (defined by accurate and timely interpretation of cues, especially risk assessment, and appreciation of implications of current situation). Poor decisions result from oversimplifying problems, ignoring

constraints, and failure to consider options.

Significance of the results

We are beginning to understand the characteristics of

problems that crews face in dynamic complex environments, the features that make problems difficult,

and crews' responses to those requirements. This

research will yield knowledge of how crews use their

expertise to deal with demanding situations, what

constitutes "best" performance in ill-structured situations, and where improvements might be made.

Publications resulting from study

Fischer, U.; Orasanu, J.; and Montalvo, M.: Effective

Decision Strategies on the Flight Deck. Proceedings

of the Seventh International Symposium on Aviation Psychology, R. Jensen, ed., Ohio State University Press, Columbus, Ohio, 1993.

National Transportation Safety Board: Annual Review

of Aircraft Accident Data: U.S. Air Carrier Operations Calendar Year 1988. (NTSB/ARC-91/01),

Washington, D.C., 1991.

Orasanu, J.: Decision Making in the Cockpit. Cockpit

Resource Management, E. L.Wiener, B. G. Kanki,

and R. L. Helmreich, eds., Academic Press,

San Diego, Calif., 1993, pp. 137-172.

Orasanu, J.: Lessons from Research on Expert Decision

Making on the Flight Deck. International Civil Aviation Organization (ICAO) J. (Special issue on

Human Factors in Aviation), vol. 48, no. 7, Sept.

1993, pp. 20-22.

61
Situation not h

adequately |

Gather

more

information

SITUATION ASSESSMENT

1. Recognize and interpret cues

2. Assess risk (present and future)

3. Assess time available

High risk I

High time pressure

Situation understood

OR undiagnosable

Apply rule

Choose option

OR

Figure 1. Simplified decision process model.

Situation understood

Low time pressure

Risk level is variable

Schedule

tasks

OR

1

Create

solution

Decision complexity depends on situation

clarity and response availability

(darker blocks are more complex)

Situation

clear

Situation

ambiguous

I | J

Ii_!_i_i_i_i_!_i_i_i_/_i_!i_!i_!i_i_iii _,!_,!iiiii_,',i _,'_'_iiii_,i_,i',i!iiiii',_,'_ii|_!_i_i_i_] [iii_i!iiii_!iii_i_:_i_ii_:_i_i_i_ii_i_:iiii_i_!ii_i_ii_!i_i_ii_i_i_i_i_i_:_!_i_i_i_i_!!!|!_.@i_i_!£_`.._i_._£_i_!_1_iii_:]

t,

|_i::i::i::_i!!i::i::i::_i!!!ii::i::ii!!!::i::_iii!!i::_iii_i!_iii!i:_i_i!iiiiii_i!i!_!iiiiiiii!iiii_:ii}ii_(ii!|____|

One Many None

Retrieve Choose Create

R or R

schedule

R

Number of responses available

and required cognitive work

Figure 2. Decision process strategies.

Orasanu, J.; Fischer, U.; and Tarrel, R.: A Taxonomy of

Decision Problems on the Flight Deck. Proceedings

of the Seventh International Symposium on Aviation Psychology, R. Jensen, ed., Ohio State University Press, Columbus, Ohio, 1993.

Key words

Dynamic decision making, Team decision making,

Situation assessment

62
Analysis of Arc-Jet Wind Tunnel Vacuum Ultraviolet (VUV)

Experiment

Investigator(s)

Chul Park, Ames Research Center,

Moffett Field, CA 94035-1000

Dikran S. Babikian, Thermosciences Institute,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The objective of this study is twofold; (1) to refine and

validate the code that calculates the radiative heating

on a blunt body behind a shock wave, especially in the

vacuum ultraviolet (VUV) spectral region, and (2) to

improve the arc-jet computational fluid dynamics

(CFD) codes to better characterize the flow in the arcjet wind tunnel. Through the computations we will be

able to better identify the thermochemicaI nonequilibrium processes in the nozzle and behind the shock

wave over a blunt body and obtain information on the

shape of the far wings of VUV lines.

Progress and results

Radiation from the nitric oxide band systems emitted

by the free-stream flow of the 20 MW arc-jet wind tunnel has been computed. A one-dimensional multitemperature code for use in an expanding flow named

NOZNT, which reproduces the nitric oxide data, was

developed. Also the flow field and the spectral radiation within the 120 nm to 1000 nm range from the

shock layer of a blunt body in the 20 MW arc-jet has

been measured and computed. The final calculation

awaits calibration of the experimental data, which is in

progress.

Significance of results

Using the NOZNT code, the nonequilibrium state in

the test section of an arc-jet wind tunnel can be

predicted.

Publications resulting from study

1. Measurement and Analysis of Nitric Oxide Radiation in an Arc-Jet Flow. AIAA 28th ThermoPhysics Conference, Orlando, Fla.

Z Validation of Multi-Temperature Nozzle Flow

Code NOZNT. AIAA 28th Thermophysics

Conference, Orlando, Fla.

3. User's Manual for NOZNT and NOZIT. Technical

note, in review.

4. Calculated and Measured Spectral Radiation from

a Blunt Body Shock Layer in an Arc-Jet Wind

Tunnel. 32nd Aerospace Sciences Meeting and

Exhibit, Reno, Nev.

5. Characterization of Arc-Jet Flows Using LaserInduced Fluorescence. 32nd Aerospace Sciences Meeting and Exhibit, Reno, Nev.

Key words

Arc-jet wind tunnel, Nonequilibrium expanding flows,

Radiative heating of blunt body

63
A Miniature, Lightweight Ozone Analyzer for Use on

Unmanned Stratospheric Research Aircraft

Investigator(s)

Richard Pearson, Jr., Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Dana Lynch, Bill Gunter, Jim Eilers, Pete Lissol,

and John Cooney, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The objective of this study was to design and test the

critical measuring components of a small, lightweight,

low-power ozone (03) analyzer for use on light,

unmanned research aircraft such as Perseus. The earliest such high altitude aircraft will be able to carry only

light, small instruments that need minimal electric

power. But to be effective, the instruments must be

reliable, accurate, and automatic.

The essential design goals were to:

• Min_ize weight, size, and power requirements so that flights with multiple instruments would

be possible.

• Provide accuracy comparable to that of the

existing instrument flown on NASA high altitude

(ER-2) missions.

• Retain the same analytical method to ensure

that the measurements would be traceable to the

National Institutes of Standards and Technology.

• Achieve a well defined optical length that

doesn't change during flight. Path length uncertainties

have caused serious problems in the accuracies of 03

measurements with a number of multipass optical

cells.

• Minimize reflections from the cell walls.

Reflections can change the effective optical length of

the cell, necessitating frequent calibrations to avoid

systematic errors in measurements.

• Work at highest altitudes (lowest pressures)

where 03 losses to the cell walls can be significant.

• Achieve a balance between the signal magnitude, which is directly proportional to optical path

length, and compactness and speed of flushing, which

require a physically short, compact cell.

• Achieve a high 6tendue to get the highest light

intensity reaching the detector. The term 6tendue is a

specific optical engineering concept related to the

speed, or light throughput of an entire optical system.

The higher the 6tendue for this system, the more light

reaches the detector from a source of fixed brightness.

Generally this permits higher signal-to-noise ratio

measurements for a cell of given optical path length.

Thus the best signal-to-noise ratio is obtained to maximize measurement precision.

The operating principle used is absorption of

ultraviolet (UV) light at 254 nanometers wavelength,

which is highly specific for 03 in ambient air. The

basic 03 photometer consists of a light source, a cell to

contain the gas to be analyzed, a light detector, and an

embedded controller to operate the unit and record the

observations and engineering data. A measurement is

made by filling the cell alternately with air to be measured, and air from the same source from which the

03 alone has been removed with a chemically selective

trap. The 03 concentration then is obtained from the ....

Beer-Lambert Law using the ratio of these two light

intensity measurements, the state parameters for the

air in the cell, the physical properties of O 3, and the

cell length. This is the recognized standard reference

method for 03. Most of the difficulties with it derive

from the fact that the light absorption to be measured

is small (typically a few parts per million) and the two

components must be measured sequentially, not simultaneously. This situation allows factors other than 03

to change the measured light intensity. In addition,

reflections internal to the cell can be---and, in many

cell designs are---an integral part of the optical path

and may change unpredictably during use of the

instrument. Such changes have the potential to cause

significant systematic errors in the measurements

without frequent intercomparisons with a transfer

standard.

The most critical design requirements were to

keep the conditions for two different light intensity

measurements as identical as possible except for the

03 content of the air, and to measure the individual

light intensities to an accuracy approaching one part

per million. For best signal-to-noise ratio, it is also

advantageous to optimize the use of the existing type

of light source, and to fit the instrument into a space in

the aircraft compatible with Argus, an instrument

designed to measure nitrous oxide and methane. It is

nearing completion for use on Perseus.

Progress and results

The main results of this study are: developing the concept for a new type of optical absorption cell particularly well suited for use under these conditions;

64
carryingoutathoroughanalysisof ageometricoptical

modelofthecompletesystemforthe03 photometer;

fabricatingandtestingaworking(visibleorinfrared

light)modeloftheabsorptioncellasproofofconcept

andasverificationof theaccuracyofthecomplex

designcalculationswithcomparativelyinexpensive

components; andcompletinganintegrated,detailed

designfortheprototypeinstrument.

Thecellappearstooperatepreciselyasexpected;

it wasphotographedinlaserlightshowingthebeam

followingtheintendedpath,exitingthroughthewindow.Oneofthemostsignificantfindingsofthisstudy

wastheconfirmationof designcalculationsshowing

thatthemechanicalandopticaltolerancesfortheopticalcomponentswouldberelativelyloosecomparedto

opticalsystemsgenerally,whichwill significantly

lowerfabricationcostsandeaseproblemsofinterchangeabilityofparts.

Thecomplexityof designingsomeof theUV

componentsandsubsystemsgreatlyexceededour

expectations. Smallchangesin opticalcomponents

necessitatedcontinualmodificationstothemechanical

design.Asaresultofincreasedesignandengineeringcosts,wewereunabletobuildandbenchtestaUV

prototypeasoriginallyintended.Butthedesignis

conservative, andextensiveconsultationshavebeen

madewithopticalproducerstobesurethatthe

customcomponentscanbefabricatedtotherequired

characteristicsandtolerances.

Significance of results

This study has developed a new concept and detailed

design for an 03 photometer small enough to be used

with other instruments on light, remotely piloted aircraft, but capable of operating at any altitude below

about 40 km so that it is compatible with use on balloons as well as use at sea level. The unique characteristics of the design involve a cell expected to have

exceptionally good stability, so that it may find applications in 03 transfer standards, or in analyzers that

must operate for extended times without reference to

an 03 standard. Nothing in the overall concept is specific to 03, so the photometer or just the cell could be

implemented for use at other wavelengths for different

gases.

The novel optical absorption cell will also operate

effectively at infrared and visible wavelengths, and it

can easily be adapted to open path applications at low

to moderate windspeeds.

Publications resulting from study: None so far

Key words

Ozone photometer, Trace gas analyzer, Optical

absorption cell

65
:_i/__',_

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Development of a Polarimeter for Astrophysical

Applications in the Midinfrared

Investigator(s)

Yvonne Pendleton, Lynne Deutsch, and

Thomas Roellig, Ames Research Center,

Moffett Field, CA 94035-1000

Introduction

The polarization of light from astrophysical sources is

an important indicator of the environment and physical processes at work in the emission region, as well as

in the intervening medium. Understanding processes

such as the life cycle of stars and the synthesis of

interstellar material increases our knowledge of how

the material that is the basis of everything around us

arrived at the proper point and at the proper time to

create the observed universe. Our approach is to combine the imaging capabilities of a midinfrared array

camera with an externally mounted polarimeter to

obtain geometrical information about astrophysical

environments otherwise obscured from view.

Statement of problem

Dust grains associated with a variety of astrophysical

settings absorb and reradiate energy at infrared wavelengths. Comparisons of midinfrared (10 _tm) and

near-infrared (2.2 _rn) polarization maps show that

observations at these wavelengths probe different

regimes and that the polarization produced at these

wavelengths arises from very different mechanisms.

At 2.2 _tm, the high degree of polarization measured is

produced by scattered light. At 10 _trn, grains cannot

scatter efficiently (due to the size of the grain compared to the wavelength of the light) and therefore the

polarization is dominated by dichroic absorption due

to aligned grains. The mechanism at 2.2 _tm reveals

information about the illuminating sources because

the orientation of the maximum electric vector remains

orthogonal to the direction of illumhnation. The mechanism at 10 _tm produces polarization by preferentially

absorbing one component of the electric vector over

the other. This can only happen if the grains are highly

aligned and elongated, so maps of 10 _rn polarization

provide information about the dust grains and their

orientation. The comparison of the polarization maps

at those two wavelengths will reveal new information

about the geometry and composition of the gas, dust,

and stars.

To illustrate the usefulness of this technique, consider the center of our galaxy, which remains hidden

from view at optical wavelengths. Infrared studies

have provided much of the current information about

the galactic center. Polarimetric studies at 2.2 _tm have

revealed the distribution of dust and some of the illuminating sources. Midinfrared polarimetric studies

have revealed information concerning grain alignment

and the effect of magnetic fields. Until now, polarization studies in the midinfrared could be done only by

using single detector technology. Figure I represents

the best midinfrared polarization map of the galactic

center that exists today. The polarization measurements for that map were painstakingly made one at a

time in a separate experiment from the one that provided the underlying photometric map. The infrared

sources labeled IRS1, 10, 5, and 8 all have strong

intrinsic polarization, which is thought to be due to the

alignment of grains surrounding the sources. The position angle of the maximum electric vector and the

magnitude of the polarization are consistent with that

which would be produced by a strong magnetic field

(>10_tG) (Aitken, et al., 1986). Such a strong field

would have significant impact on the structure and

evolution of the galactic center. The change in position

angle and the smaller polarization seen in the other

sources in figure I is attributed to differences in grain

composition and aligrunent in the southern portion of

the map. The Ames 104tm polarimetric imager can

simultaneously provide photometric and polarimetric

images of a 14- by 14-in. area of the sky and increase

the resolution of the map shown in figure I to a

resolution of I in. per pixel (as shown by the box in the

upper right hand portion of the figure).

Instrumentation and methods

NASA-ARC 10/20 _rn camera: A new infrared camera

(AIR Camera) has been developed at NASA Ames

Research Center for observations from ground-based

telescopes. The heart of the camera is a Hughes 58 x

62 pixel arsenic-doped silicon detector array that has

the spectral sensitivity range to allow observations in

both the 10- and 20-micron atmospheric windows.

Three discrete 8% filters at 18, 20, and 22 microns, a 3%

circular variable filter covering the 7.5- to 14-micron

atmospheric window, and discrete 10% filters centered

at 9.8 and 10.3 microns can be selected to define the

spectral resolution. A very flexible optical design and a

dedicated guider/mounting box allow camera operation at any major telescope that has a focal ratio of

17 to 45. The camera has been used for observing runs

66
cO=_

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a

_28o58'50 ''

_28o59'OO ''

_28o59'30 ''

I I I I I i I " 1 " "

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12.5pro polarimetry

5

0

1

7

/

@/

/

/ 3 6

@

4

2

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9

I I I I I I I I I

17 h 42 m 30.0s 29.0s

Right ascension (1950)

Figure 1. Intrinsic 12.5 lam polarization measurements of the galactic center (Aitken et al., 1986) superposed on the 12.5 [am

flux contour map (Becklin et al., 1978). The length of the dark lines indicates the percentage polarization while the orientation

of the line shows the position angle. The array size of the 10/_m camera is shown by the cross-hatched box in the upper right

corner and the pixel size is drawn in as a 1-inch square.

at the Mt. Lemmon 1.5-m NASA/UA telescope. When

using this telescope, each camera pixel corresponded

to a square 0.73 arc-seconds wide on the sky, which

gave a total camera field-of-view of 42 x 45 arcseconds. At the NASA Infrared Telescope Facility in

Hawaii a smaller pixel scale gives a 14-in. field-ofview.

The optics of the AIR Camera are very simple,

consisting of a single lens that simultaneously

reimages the sky image formed by the telescope onto

the detector array as it images the telescope secondary

mirror onto a cold stop at the entrance to the array

enclosure. Two filter wheels select from among the

available filters, rotating them into positions just in

front of the cold stop. The optical design (fig. 2) allows

changing between telescopes of different focal ratios

by changing the reimaging lens while keeping the

filter wheels, cold stop, and array undisturbed.

67

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Beam from telescope

secondary mirror

Telescope

primary

mirror

Dichroic

mirror

i

i

Telescope facility

visibilty TV camera

F]F1

J

• T

_ _ Polarizer

_ Wire Grid Analyzer

Reimaging

optics/filters

58 X 62

Si:As array

Polarizer

rotating

half-wave

plate

Figure 2. Schematic representation of the polarimeter and midinfrared camera assembly.

i_:+/i_ i:!!:i/_:_

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Ames midinfrared polarimeter

The design of the near-infrared polarimeter consists of

a fixed wiregrid analyzer (which is cryogenically

cooled) and a rotating half wave plate. The materials

used for the optical components are an Ar coated germanium wiregrid and a cadmium sulfide half waveplate. These materials were chosen because they

provide optimum characteristics for midinfrared

polarimetry. The wiregrid analyzer resides in a filter

wheel position inside the cryogenically cooled camera.

The rotating half wave plate is housed inside a cylindrical mount that is motor driven.

Astronomical results

In figure 3(a-b) we present new astronomical

images obtained with the AIR Camera at NASA's

Mt. Lemmon telescope. These images show emis68

sions from the young planetary nebula NGC 7027 at

two midinfrared wavelengths. Planetary nebulae are

the ejected envelopes of evolved stars. The central star

of NGC 7027 is totally obscured by dust in the optical,

has a temperature of 180,000 to 234,000 K, and is

located approximately I kpc from our Sun. The midinfrared images reveal a double lobed structure and a

central minimum, which represent a cross-section of a

tipped toroid of gas and dust. The dust ejected by

planetary nebulae has been enriched with heavy

elements created through the star's nucleosynthesis.

The nebula also contains large carbon molecules,

which may be the building blocks of prebiotic

material. This material is ultimately reincorporated

into the interstellar medium from which new stars will

be formed.
Ongoing research efforts

Now that the AIR Camera has been tested at the telescope, the polarimeter can be used in conjunction with

the camera. The next step in this project includes taking the camera/polarimeter to various telescopes to

observe objects such as NGC 7027 and the galactic center to further study a variety of astrophysical

environments.

References

Aitken, David K.; Roche, Patrick F.; Bailey, Jeremy A.;

Briggs, Gorden P.; Hough, James H.; and Thomas,

John A.: Infrared Spectropolarimetry of the Galactic

Centre: Magnetic Alignment in the Discrete

Sources. Monthly Notices of the Royal

Astronomical Society, vol. 218, 1986, p. 363.

Becklin, E. E.; Mathews, K.; Neugebauer, G.; and

Willner, S. P.: Infrared Observations of the Galactic

Center. IV. The Interstellar Extinction. Astrophys. J.,

vol. 220, Mar. 15, 1978, pp. 831-835.

Key words

Midinfrared polarimetry, Two-dimensional array

camera

69
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Three-Dimensional (3-D) Disturbances Generated by

Suction Holes for Laminar Flow Control (LFC)

Investigator(s)

Daniel C. Reda and Jonathan H. Watmuff,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Wes Lord, Pratt & Whitney,

East Hartford, CT 06108

Objectives

The benefits of using suction for delaying transition

to turbulence have been known for some time, but

only recently has the technology become available

to produce large sheets of perforated material for

use in aircraft wings at reasonable cost. However

there is evidence to suggest that local threedimensional (3-D) disturbances are generated by the

discrete holes, which could defeat the purpose of

the suction, i.e., cause premature transition. The

objective of this research is to determine the characteristics of these disturbances, whether they

decay or amplify with streamwise distance, and

whether there are interactions between disturbances

generated by different holes.

Progress and results

This initial DDF funding was used to modify an

existing facility, which has been completed on

schedule. Measurements of the background flow are

under way. The test section unsteadiness is 0.08%

and the transitional Re = 2.2 x 106 for an impervious fiat plate, which is very good for an openreturn blower driven tunnel. The mean flow exhibits

the Blasius profiles although the data have not

been fully analyzed as yet. Disturbances generated

by an isolated suction hole will be investigated

shortly. The suction will be perturbed harmonically

and the data phase-averaged on the basis of the

perturbation. Measurements will be made on spatially dense 3-D grids allowing animations of the

T-S-like 3-D waves to be studied on a graphics

workstation. A scaled-up porous surface consisting of

8,966 holes is ready for testing. This will be used to

investigate the interactions between disturbances on

a full suction surface typical of those currently being

flight tested for future use in airplane wings and _:

engine nacelles. ......

Significance of the results

The holes have been scaled up by a factor of 20 to

allow direct observation of the disturbances' Of special interest is the interaction between disturbances

originating from two holes displaced, but aligned in

the streamwise direction. There is likely to be some

degree of enhancement, or more relevantly, some

degree of cancellation of these waves. If cancellation is observed, then it is possible that the streamwise grid spacing of the holes should be designed

for a specific flight speed (i.e., T-S wavelength).

Current design practice considers only the spanwise

grid spacing.

Publications resulting from study

Watmuff, Jonathan H.: Interaction Between

Instabilities Originating from Suction Holes. To

be presented at the 46th Annual Meeting of the

APS Division of Fluid Dynamics, Nov. 1993.

Key words

Laminar flow control, Suction holes

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An Ultralow-Temperature Thin-Film Thermometer

Investigator(s)

Pat Roach, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

A1 Spivak and Mic Clark, Ames Research Center,

Moffett Field, CA 94035-1000

Step I has been completed and the mask pattern is

shown in the figure. This pattern achieves a length of

40 cm and a width of 0.01 cm in an area of only I cm 2.

Its surface area is 0.4 cm 2 for good thermal contact.

Objectives of the study

The purpose of this project is to develop a simple,

accurate thermometer that will be useful in the temperature range of 0.01-0.38 K for use with cryocoolers

that are being developed to operate at 0.10 K and

below. There are currently no thermometers operating

in this range that are reliable, accurate, and simple

enough for unattended operation in an orbiting telescope. We hope to show that a thin-film resistance

thermometer can be developed that is both sensitive

and reproducible after cycling to room temperature.

Because it will be a resistive device, it will be very

simple to measure.

The idea behind the thermometer is that certain

gold-aluminum alloys have a superconducting transition temperature that depends on the ratio of the two

metals. We will create a thin-film serpentine pattern of

Au-A1 alloy that varies continuously in its composition

so that the region of 86%Au-14%A1 begins to superconduct at 0.38 K, and more of the pattern becomes

superconducting as the temperature decreases until

the last region of 96%Au-4%A1 becomes

superconducting at 0.01 K.

The objectives are:

1. Design the serpentine pattern to maximize the

pattern length and area of thermal contact in a small

package. Make a corresponding mask.

2. Evaporate the gold and aluminum films in the

correct composition gradient.

3. Etch the pattern in the film and diffuse the Au

and A1 together.

4. Evaluate the thermometer behavior

(sensitivity and reproducibility) at low temperatures.

5. Develop solutions for problems that are

revealed. Possible problems are sensitivity to air or

moisture, sensitivity to the Earth's magnetic field, poor

thermal contact, hysteresis in the superconducting

transitions, and problems with electrical contacts to

the thermometer.

Serpentine pattern for thin-film thermometer.

Preliminary tests with samples of Au-A1 films

have revealed that the nearly pure gold alloy is very

soft and does not bond well to a sapphire substrate but

it can be soldered for lead attachment. The 14% A1

alloy is much harder and bonds better to the substrate,

but it cannot be soldered for lead attachment. Experiments with several conducting epoxies have produced

mixed results. Leads can sometimes be attached to the

alloy with good results at low temperatures but at

other times the joints develop a high resistance at low

temperature.

The results so far indicate that the alloy film will

have to be handled carefully to avoid damaging the

regions where it is soft and poorly bonded. Methods of

improving the bond generally involve layers of other

metals below the Au-A1 alloy and would not be advisable in this application. We feel that the use of silver

epoxy to attach leads can be made to work if sufficient

care is taken.

Key words

Resistance thermometer, Low temperature,

Superconducting thin film

71
Early Warning Blackout Sensor for Pilots and Astronauts

Investigator(s)

S. A. Rositano, Alan Hargens, and

Malcolm Cohen, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

To develop and evaluate a forehead-mounted impedance measuring patch capable of providing a 4- to

7-second advance warning of impending physiologic

limit (blackout) caused by head-to-toe acceleration

forces.

Progress and results

Signal processing circuitry has been designed and

tested with simplified electrodes. A contract has been

awarded to Classic Medical for production of prototype electrodes. The first integrated test was scheduled

for November 1993. Preliminary results indicate high

probability for detecting the arterial pulse.

Upon successful tests on resting human subjects,

tests on the ARC 20-G Centrifuge will be conducted.

Refinements in electronics are expected to provide

"smart signal processing" for adaptive artifact

suppression.

Key words

Biomedical technology, Biomedical electrodes, Pilot

safety

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72
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The Infrared Spectra of Microsamples of Cosmic Interest:

Diamonds, Silicon Carbide, Interplanetary Dust Particles,

and Organic Residues

Investigator(s)

Scott A. Sandford, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Louis Allamandola, Douglas Hudgins, and

Robert Walker, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The purpose of this investigation is to obtain the

infrared spectra in the 4000-400 cm -1 range of a number of different kinds of microsamples. These samples

include, but are not restricted to, (1) diamond and silicon carbon grains that are found in meteorites that are

known from isotopic anomahes to have an interstellar

origin, (2) individual interplanetary dust particles

(IDPs) collected in the stratosphere by NASA high altitude aircraft, and (3) organic residues found in meteorites and produced in laboratory simulation experiments in our low-temperature laboratory.

The spectra from these samples can be used to

determine the chemical and mineralogical composition

of these samples, thereby allowing us to draw inferences about the environments in which they formed

and about subsequent processes they experienced in

interstellar and interplanetary space and within their

solar system parent bodies (asteroids and comets). The

spectra can also be compared directly to telescopic and

remote sensing data. Such comparisons help identify

these materials in space and allow us to better determine their cosmic distribution and abundance.

Progress and results

The majority of the DDF funds allocated to this study

were used in the purchase of an infrared microscope.

The infrared microscope, a Nicolet IR-Plan, has now

been fully integrated with our Nicolet 740 Fourier

transform infrared spectrometer and has been thoroughly tested for performance and compatibihty. The

system is designed to provide a great deal of flexibility, a key requirement since the spectrometer used

with the microscope is also responsible for carrying

out other experimental studies on macroscopic sampies. It was found that the entire system can be

switched from normal operation to microscope operation or vice versa in about an hour. Optimization of

the system for difficult samples often requires longer

times, with about a half day being typical.

The microscope itself has been found to perform

up to expectations. Once the overall spectrometer

system is configured for microsample work, it can

provide a good quahty infrared spectrum of micronsized samples inas httle as 10 minutes. Prior to the

installation of the microscope, it would have taken at

least 2 days to obtain such a spectrum and it would

have resulted in decidedly inferior data. The infrared

microscope therefore represents a 300-fold plus

improvement in our ability to study microsamples.

Spectra obtained from microscopic samples that were

previously characterized in larger quantities using

more traditional techniques demonstrate that the

microscope produces reliable and repeatable results.

Now that the microscope can rapidly measure the

spectra of microsamples, the biggest bottleneck in

these studies is the preparation and mounting of the

samples themselves, which are, not surprisingly, difficult to handle because of their extremely small sizes.

We have used our remaining DDF funds to equip a

modest microsample preparation bench with an optical microscope and hght source. We have also

designed and built a specialized adjustable sample

holder that can be used to mount a variety of different

sample types into the microscope's sampling area.

Significance of results

The work done in the past year demonstrates that the

new infrared microscope works well and can be used

to routinely measure the iPdrared spectra of nanogramsized quantities of material with both rapidity and a

high degree of rehability. Based on the results of our

tests with standard materials and the work done on

cosmic microsamples already characterized using

other techniques, we expect the microscope to generate exciting new discoveries.

The successful installation of the infrared microscope opens up a wide variety of possible study areas

that were previously impractical to consider. So far,

the microscope has been used to study a number of

samples from Antarctic meteorites in the ureilite class

and to study a variety of polycychc aromatic hydrocarbon (PAH) species common in the organic portions

of meteorites. Plans are presently under way to begin a

73
collaborativeffortwithDonBrownleeoftheUniversityofWashingtontousethemicroscopetostudy

theorganiccomponentsininterplanetarydustparticles.Dr.Brownleewill providewholeparticlesamples

andultramicrotomed(ultra-thin)sectionsof interplanetarydustparticles,whichwewill examineusingthe

microscope. Weintendtofocusontheorganicfraction

oftheparticles.Thiscomponentispresentlytheleast

wellunderstoodofallthephasesininterplanetary

dustparticlesandisknown(fromdeuteriummeasurements)tocontainaninterstellarprecursormaterialwhosecharacterisnotunderstoodatthistime.

Publications Resulting from this Study

No publications resulting solely from this study have

yet been submitted, although we hope to be able to

complete a paper on the organic component of interplanetary dust particles during the upcoming year.

However, the microscope has already been used to

verify certain key points in two other papers. The first

paper is entitled "The Mid-Infrared Transmission

Spectra of Antarctic Ureilites" and is presently in press

in Meteoritics. The second paper, entitled "Infrared

Spectroscopy of Polycyclic Aromatic Hydrocarbon

Cations I: Matrix Isolated Naphthalene and Perdeuterated Naphthalene," is presently in press in The

Journal of Physical Chemistry.

Key words

Infrared spectroscopy, Microsamples, Extraterrestrial

materials

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74
Development of a Direct Measurement Transducer for the

Oil Wedge Skin-Friction Technique

Investigator(s)

H. Lee Seegmiller, Ames Research Center,

Moffett Field, CA 94035-1000

the oil wedge. Furthermore, if a means of exuding the

oil through a slit near the transducer can be developed,

the method could be used in full-scale flight vehicles

or large continuously running wind tunnels.

Objectives of the study

The objective is to develop a new nonintrusive means

of measuring skin friction. The recently developed

laser interferometer oil wedge technique is regarded as

a reliable and nonintrusive means of obtaining skinfriction measurements in certain flows. In this technique, the thinning rate of a wedge of oil on the model

surface is related to the friction force at the oil-gas

interface. The oil thickness is determined from alternating constructive and destructive interference

between laser beams reflected from the surfaces of the

oil and model as the oil wedge thins.

Although reliable results have been obtained with

this method, the requirement for optical access prevents its use in the internal flows of nozzles or inlets.

The laborious and time-consuming setup of the laser

and detector also severely restricts the opportunity to

make simultaneous measurements at various model

locations, resulting in lengthy and expensive tunnel

test programs. Additional limitations of the interferometric method are the presence of tunnel or model

vibrations or model or aircraft structural deflection

occurring in response to aerodynamic or thermal

effects.

A new, rugged, flush-mounted transducer is proposed that may make direct measurement of the oil

wedge thickness possible. Unlike the laser interferometric method, the proposed transducer would provide continuous measurement during the thinning of

Progress and results

A new state-of-the-art capacitance bridge has been

obtained, and several prototype transducers have been

fabricated. Testing of several transducer configurations has resulted in a candidate design for testing in

the High Reynolds Pilot Channel. This design is now

being fabricated and will include provision for oil

injection to permit repeated measurements as required

for a continuously running tunnel or for aircraft in

flight. During testing of concept configurations to

evaluate temperature sensitivity, it was discovered

that the transducers were highly sensitive to condensed moisture as they were cooled below the dew

point. As spinoff technology, it is believed that this

sensitivity to water and ice can be exploited in a very

different application. Consequently, tests were conducted to see if a modified transducer could be used as

an aircraft ice detector. These tests were successful and

a U.S. patent application has been filed. The proposed

ice-detector would not only indicate the presence of ice

on aircraft surfaces but also advise the flight crew of

the need to reapply deicing fluid during ground

operations.

Significance of the results: None so far

Key words

Liquid film thickness measurement

75
Utility of the Experimental Electro-Optical Camera (SPEC-T)

for Assessment of Insect/Drought Related Forest Mortality

Investigator(s)

Gary A. Shelton and Vincent G. Ambrosia,

Ames Research Center,

Moffett Field, CA 94035-1000

James McKean, U.S.D.A. Forest Service,

Pleasant Hill, CA 94523

Other personnel involved

John C. Arvesen, Ames Research Center,

Moffett Field, CA 94035-1000

Edward A. Hildum, SVERDRUP,

Ames Research Center,

Moffett Field, CA 94035-1000

Jeffrey S. Myers, ATAC, Inc.,

Ames Research Center,

Moffett Field, CA 94035-1000

Objective of study

Evaluate and test the application of a newly developed, high spatial resolution, electro-optical digital

camera (SPEC-T) for use in detecting insect/drought

related forest mortality and other environmental

assessments that require high spatial/spectral resolution data sets. Test and evaluation of system configuration and utility for inclusion of SPEC-T as part of

NASA's supported suite of research and applications

aircraft instnm_ents.

Progress and results

An intensively managed study site was located in conjunction with the U.S.D.A. Forest Service with known

forest mortality (McCloud, Calif.). An ER-2 mission

flight with the SPEC-T system aboard was flown over

the area in spring 1993. Analysis of the resultant data

indicated an engineering problem with the data

recorder and components of the tilting/timing mechanism. The resultant data were unusable for the objectives assessment. The instrument was corrected and

deployed to the South Pacific for missions, but again

failed. As of September 1993 the instrument is in

reconfiguration to allow for reliable data collection.

Possible test flights in support of this DDF will occur

early in FY94, as well as during the optimum collection

period in spring 1994. Funding for aircraft flight time

was utilized in FY93, and remaining funds were

forwarded for FY94 contract analysis support. Request

for FY94 funding is to support engineering benchmark

testing and engineering support for furthering operational development of the SPEC-T to preclude further

mechanical failures.

Significance of results

During the in-house development and trouble-shooting of the SPEC-T system, the engineering staff are

familiarizing themselves with a unique instrument

and operation of that instrument. This DDF funding,

besides supporting the scientific/ecosystems analysis

phase, also assists in furthering the development of a

new, unique airborne system built exclusively at

Ames. Further, NASA-Johnson Space Center and the

U.S. Navy (including the Naval Post-Graduate School,

Monterey) are developing and utilizing a similar system on the shuttle. Our cooperation and discussion

have led to suggestions on improvements to their system and the utility of the data obtained from a spaceborne instnlment. Further discussions are continuing,

leading to a potential coordinated shuttle overflight/

ER-2 underflight with both systems operational for

comparison of imaging characteristics.

Key words

Electro-optical camera, Remote sensing, Ecosystem

analysis

76
A Neural Learning Algorithm for Touch Based Control of

Mechanical Manipulation

Investigator(s)

Jay Steele, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

A fundamental NASA goal is to return an active

human presence to the Moon and establish a lunar

base. The technological problems facing NASA in this

future endeavor to build, maintain, and operate a base

in the extremely hostile lunar environment are very

challenging. We feel that automating vehicles and

manipulators to accomplish tasks in the lunar environment is essential to the successful solution to these

problems. Specifically, the ability to safely control the

movement of autonomous or semiautonomous guided

vehicles and manipulators in a cluttered work space

with potentially dynamic obstacles is a critical technology area. The purpose of this study is to develop a

new neural learning system capable of handling the

control problem of moving these vehicles and manipulators safely around perceived obstacles toward specified goals. The complete system must be capable of

learning and storing information about the world in

addition to controlling a physical robot with a real

time control loop.

Progress and results

During the first year of this research, we experimented

with several different learning systems and focused on

a reinforcement learning system. This system uses an

evaluation function that returns the most appropriate

action for a given state that allows the robot to reach

its goal safely. This evaluation function gradually

improves over time, as the tendency to take appropriate actions is reinforced while the tendency to take

inappropriate actions is decreased. Appropriate

actions are defined to be actions that produce short or

long term success, whereas inappropriate actions produce the opposite results. The evaluation function is

structured around the vehicle's possible actions and is

developed by the vehicle's interaction with the geometry of its environment.

This reinforcement learning approach worked successfully with vehicles moving in a finite sized, planar

world. Applying this approach to controlling articulated robot arms in three dimensions with a consequently larger action space created impossibly high

memory requirements for the evaluation function. In

order to solve this problem, an evaluation function

that is evolved with a better knowledge of the intrinsic

geometry of the articulation of the robot arm and

vehicular motion is required. In short, the geometry of

the evaluation function must match the external

geometry of the robot arm.

As a means to creating a better evaluation function

for determining robot motions, we turned to the tensor

network theory, which describes the internal representation for the cerebellum of the geometries of muscular

movement. Furthermore, this theory models the interaction between this representation and the sensory

geometry representation, which begins to explain sensorimotor coordination in the brain. We set up a controller for the Puma robot arm based on this tensor

theory and it successfully calculated appropriate joint

movements to reach toward specified goals after an

initial learning phase. More research is required in the

next year, however, in order to expand upon this tensor theory to discover mathematics that will emulate

the brain's ability to control movements beyond simple reaches and to move around obstacles.

Key words

Neural network, Arm path planning, Learning

77
Development of a New System for Canopy Architecture

Remote Sensing

Investigator(s)

V. C. Vanderbilt, Ames Research Center,

Moffett Field, CA 94035-1000

A. W. Sarto and B. J. Van Zeghbroeck,

University of Colorado, Boulder, CO 80309

Objectives of the study

This remote sensing project will develop a new theory

and measurement method for an emerging remote

sensing technology--canopy architecture remote

sensing_which will supplement the existing optical

and microwave remote sensing technologies.

Progress and results

We are developing a new theory and a new laser

based measurement method for remotely sensing

canopy architecture. The theoretical development

supports development of a proof-of-concept

instrument.

Theoretical Development

We divided the theoretical problem of understanding

and extracting the information in the laser pulse

returned to a lidar from a canopy into two parts.

• During this first year, we have developed a

stochastic process model to mathematically describe

canopy architecture.

• During the coming year, we will use the

results of our architecture model to develop a second

model, an engineering interaction model, describing

the interaction between a spatially and temporally

modulated laser pulse and the architecture of a plant

canopy.

In our newly developed stochastic architecture

model, the stochastic variable is not time but rather

(x,y,z) position and possibly (q,f) direction in the

canopy. In the model, the canopy statistical properties

are computed from the statistical properties of an

ensemble of 'plots' selected from within the canopy.

This model supports definition of an autocorrelation

function for canopy architecture, providing a fundamental measure of canopy architectural properties.

Examples in this report illustrate application of the

theory to the problem of quantifying canopy

architecture.

Development of a proof-of-concept instrument

Recent research has demonstrated the potential of

metal-semiconductor-metal (MSM) photodetectors to

attain extremely short response time constants

required for use in the canopy architecture measurement system. The research has shown that these

extremely fast MSM photodiodes, fabricated as single

detectors or as arrays of detectors, perform well in a

frequency mixing mode of operation, a fact which we

have exploited in the design of the canopy architecture

measurement system.

Rather than acquire data at gigahertz (GHz) frequencies, the canopy architecture measurement system

we are developing will sample the output of a superfast array of MSM photodetectors with gigahertz

bandwidth, allowing data collection at a much lower

frequency than the GHz regime. This sampling design

takes advantage of the signal mixing capability of the

MsM photodiodes and avoids the need to fabricate a

GHz transmission line connection to each element of

the array.

During the past year, we have designed and fabricated at the University of Colorado extremely high

speed, MSM photodetectors_both single detectors

and arrays of detectors_for use in the proof-ofconcept lidar canopy architecture sensor (fig. 1). The

MSM detectors, the critical component in the canopy

architecture instrument, are capable of providing an

output current proportional to the incident light

(fig. 2). The prototype, proof-of-concept lidar sensor

uses high-speed galium-arsenide, MSM photodetectors, developed at the University of Colorado (B. J.

Van Zeghbroeck et al., 1990), implemented in an optical correlation system. The optical correlation design

takes advantage of the signal mixing capabilities of

MSM photodetectors, avoiding the need for expensive,

often one-of-a-kind electronic components with GHz

bandwidths while allowing signal processing of the

return laser pulse waveform, its analog-to-digital conversion, and storage of the digital data with the aid of

cheap, yet high quality, off-the-shelf hardware. The

prototype system will be developed at Ames Research

Center during the coming year. In a laboratory test a

sample MSM detector exhibited a response time that

would allow the architecture of even miniature

canopies to be measured (fig. 3).

78
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Significance of the results

The progress and results to date lay the foundation for

our efforts during the second year of the project. Our

new model for canopy architecture provides the

needed theoretical structure upon which to develop

the engineering model of the instnm_ent operation.

The MSM detectors and detector arrays that we have

fabricated are essential for developing the prototype

instrtunent during the second year.

Publications resulting from study

A draft report, Stochastic Model of Plant Canopy

Architecture, has been written by V. C. Vanderbilt

(1993).

References

Van Zeghbroeck, B. J. et al." High-Speed GaAs/

A1GaAs Optoelectronic Devices for Computer

Applications. IBM J. Research and Development,

vol. 34, 1990.

Key words

Canopy architecture, Stochastic model of canopy

architecture, Measurement of canopy architecture

79
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80
Optimization of Spatial Auditory Displays for Multiple

Communication Channel Intelligibility

Investigator(s)

Elizabeth M. Wenzel and Durand R. Begault,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The study seeks to determine the optimal placement of

multiple radio communication channels using 3-D

sound techniques, so that speech intelligibility in contexts such as NASA-KSC launch operations is

improved. A concurrent DDF from Kennedy Space

Center (KSC) allowed the development of a prototype,

the Ames Spatial Auditory Display (fig. 1). The Ames

DDF supports psychoacoustic experiments for

determining intelligibility as a function of placement

on the virtual acoustic azimuth, with frequency

response and launch control environment conditions

as additional independent variables.

Figure 1. Ames Spatial Auditory Display.

Progress and results

Figure 2 shows the results of an experiment designed

to measure intelligibility of four letter call signs used

by KSC personnel as a ftmction of incremented 30-deg

virtual azimuths. The solid line represents results for a

group of "naive" listeners, and the dotted line represents results from hsteners familiar with the call signs.

It can be seen that a 6-7 dB improvement results at the

optimal positions of 60 and 90 degrees azimuth.

Significance of the results

The 6-7 dB advantage for 60- and 90-deg head-related

transfer function (HRTF)-filtered speech represents a

minimum halving of the intensity (acoustic power)

necessary for correctly identifying four letter call signs

typical of those used in communication systems at

KSC. This reduction in the likelihood of misinterpreting call signs over communication systems is an

important safety improvement for "high stress,"

human-machine interface contexts. The binaural

advantage could also benefit communications

personnel because the overall intensity of communications hardware could be reduced without sacrificing

intelligibility, and volume adjustment of a desired

individual channel can occur less frequency. Lower listening levels over headphones could possibly reduce

the risk of threshold shifts, the Lombard Reflex

A8

m

O

.a6

Q.

O°,m

.2 4

"o

O

o

c_2

m

e-

<o

[] Naive subjects

O Experienced subjects

I I I I I

30 60 90 120 150 180

Azimuth of spatialized signal

(mean of left and right sides)

Figure 2. Intelligibility of four letter call signs used by KSC

personnel as afunction of incremented 30-deg virtual

azimuths.

81
(raising the intensity of one's own voice), and overall

fatigue. Overall, the findings here suggest that the use

of a spatial auditory display could enhance both occupational and operational safety and efficiency of

NASA operations.

Publications resulting from study

Begault, D. R." Audio Spatialization Device for Radio

Communications. Patent Disclosure No.

ARC 12013-1-CU. NASA Ames Research Center.

Filed with U.S. Patent Office, Sept. 1993.

Begault, D. R." Call Sign Intelligibility Improvement

Using a Spatial Auditory Display. NASA

TM-104014, 1993.

Begault, D. R.: Call Sign Intelligibility Improvement

Using a Spatial Auditory Display: Applications to

KSC Speech Communications. In Proceedings of the

Space Operations, Applications and Research

(SOAR) Conference, Houston, Tex.: NASA Johnson

Space Center, 1993.

Begault, D. R.; and Erbe, T. R.: Multichannel Spatial

Auditory Display for Speech Communications. In

Proceedings of the 95th Audio Engineering Society

Convention., Preprint No. 3707, Audio Engineering

Society, New York, N.Y., 1993.

Key words

Speech intelligibility, 3-D audio displays,

Communication systems

82
Musculoskeletal Loading or Unloading with Differential

Pressure

Investigator(s)

Robert Whalen and Gregory Breit,

Ames Research Center,

Moffett Field, CA 94035-1000

Douglas Schwandt,

Rehabilitation Research and Development

(RR&D) Center,

Palo Alto, CA 94304

Other personnel involved

Charles Burgar, RR&D Center,

Palo Alto, CA 94304

Introduction

We have proposed a novel method of using air pressure to apply an external axial force to the body,

coincident with the body's center of mass, that has

the potential of enabling Earth-equivalent musculoskeletal forces in space [Whalen et al., 1991;

Hargens et al., 1991]. Since gait is primarily controlled by gravity acting at the center of mass and

only secondarily by its distributed action on limb

segments (He et al., 1991; McMahon and Cheng,

1990), we hypothesize that near-normal exercise

walking and running are possible in space by combining a treadmill with this method of loading the

body. This consideration is important since current

exercise devices are not capable of generating skeletal force levels and daily loading histories of sufficient magnitude in space to maintain the musculoskeletal system without lengthy daily exercise

periods [Whalen, 1993]. Furthermore, by reversing

the direction of the pressure differential, walking

and running at musculoskeletal levels below normal

one-G walking, i.e., simulated hypogravity locomotion, are possible on Earth. With our DDF

research, we have pursued the application of differential pressure as a countermeasure device for use

in space and, in collaboration with the Palo Alto

Veterans Administration (VA) RR&D Center, as a

walking assist device for rehabilitation.

Objectives of the study

The objectives of this research were

• to design and fabricate an air pressure

chamber and treadmill assembly,

• to test the hypothesis that Earthequivalent skeletal forces are achievable in

microgravity,

• to simulate hypogravity and hypergravity

locomotion on Earth.

Theory

The method of developing a "noncontact" force at

the mass center of the body is illustrated in

figure l(a). The upper and lower body are separated

(a)

z

x

+ FS

(b)

2.0

A

W

.c 1.5

0

.a

LI..

rr 0.5

0

m

I

i

r !

6o

UBPP LBPP

[] Subject 1

o Subject 2

o

_o

o

_o

o

I i I i , I I P

40 20 0 20 60

0

80

I i

4O

Pressure differential (mmHg)

Figure 1. Differential pressure chamber with treadmill

and pressure force calibration data. (a) Treadmill walking at 2 m/s and treadmill running at 3 m/s. Note the

characteristic ground reaction force profiles, suggesting

proportional lower limb musculoskeletal loading.

(b) Hypergravity is simulated by a positive lower body

pressure.

83

................................. ...............................  ̧ ̧-.7 ̧ ̧ ̧, ̧ ̧/iiii_ _,_IL _ _,!,
by a flexible airtight seal that permits free lateral

and vertical movement. The direction of the pressure difference between the upper and lower body

determines the direction of the resultant force. We

have used upper body positive pressure (UBPP) to

simulate or augment gravity (hypergravity) during

locomotion and a lower body positive pressure

(LBPP) to simulate hypogravity. The seal can provide an additional shear force whose magnitude

depends on the unrestrained exposed area of the

seal. Body weight on Earth, the pressure force, seal

shear force, and inertia forces all contribute to the

resultant ground reaction force (GRF).

Progress and results

We have built a treadmill and computer-controlled

upper body air pressure system capable of imposing

high force levels on the body and have used the

system to simulate hypergravity locomotion on

Earth. With this design a 3-foot-diameter inflatable sphere, constructed from a lightweight coated

fabric, encloses the upper body. The sphere is tethered to the treadmill with four tension straps that

balance compression forces applied to the body by

the pressure, shear, and inertia loading. In collaboration with the VA RR&D Center we have also

constructed a LBPP system to investigate subject tolerance to LBPP in order to develop a walking assist

device for patients recovering from a stroke, incomplete spinal cord injury, or joint replacement surgery.

Lower body positive pressure provides support to

patients who need to begin exercise walking on a

treadmill with reduced ground reaction and joint

forces. The relationship between the pressure differential and the GRF force during a static calibration test is shown in figure l(b).

Hypergravity and hypogravity simulation

Ground reaction force data while walking and running on the treadmill were collected at 1.0, 1.3, and

1.6 G (0, 20, 40 mm Hg) using a capacitance insole

force sensor. Typical gait cycles of treadmill walking at 2 m/s and treadmill running at 3 m/s at 1.0 G

and 1.6 G are plotted in figure 2(a). Peak force levels at toe-off increased as expected with increasing

"G-level" (see fig. 2(b)). Running data collected at

different G-levels were normalized by the stride

period (Tstride) and the effective body weight,

computed by multiplying Earth body weight by the

effective gravity. Normalized peak GRFs decreased

with increasing G-level indicating that muscle force

generation is a limiting factor to hypergravity gait.

Interestingly, ground contact time at a fixed gait

speed was constant, i.e., independent of gravity.

3.0 F Walking @ 1.0g

-_, 2.5 _ f"-, Running@l.0g .c" _\/ \ \ .... Walking @1.6g

m \ Running@l.6g

o \

_= 1.o

0 .5

o - I "--t---- I

0 .2 .4 .6 .8

Time (sec)

(a)

3.0

A

¢/) " 2.5 J::

.m

O

2.0

"{3

O

J= 1.5

O_

ILL

rr 1.0

o

¢g .5

a.

(b)

m

ea

Hypogravity

Running ,,

(3.0_s).... "

ea

ea

ea

Hypergravity

J

Walking

(2.0 m/s)

I I I

•50 .75 1.00 1.25

Effective gravity (g)

I ! I

0 .25 1.50 1.75 2.00

Figure 2. Ground reaction forces during gait at different

effective gravity levels. (a) Treadmill walking at 2 m/s

and treadmill running at 3 m/s. Note the characteristic

ground reaction force profiles, suggesting proportional

lower limb musculoskeletal loading. (b) Hypogravity

simulation values are extrapolated. The plots also

express the relative change in lower limb musculoskeletal loading since internal forces are scaled approximately

by the magnitude of the ground reaction force.

Results extrapolated to hypogravity locomotion in

figure 2(b) agree with recent hypogravity locomotion studies (He et al., 1991). In preliminary tests

performed at the VA RR&D Center, normal subjects

tolerated LBPP without significant effect on the

cardiovascular system. In these studies a positive

pressure of 45 mm Hg supported approximately 75%

of body weight.

Conclusions

We have verified that differential pressure loading is an effective and feasible method of altering

GRFs during gait. Furthermore, since the profiles of

84
! i

i_i_!i!ii!iiiii i_i! i

iii_!_iii!!!i i_!__

i_i ii ,! i

!__i _i_,_ ,

_ _i_:ii!_ii_

i i_iiii!i_!i!_i_i_ _iii !'

the GRFs are similar at different "G-levels," this

result suggests that the internal musculoskeletal

forces that contribute to the resultant GRF are proportionally changed. We believe Earth-equivalent

lower limb musculoskeletal forces can be generated

in space with this device.

Significance of results

1. Differential pressure loading with treadmill exercise is a promising method for maintaining

the musculoskeletal and cardiovascular systems of

humans in space.

2. Lower body positive pressure may be used to

assist walking by supporting the body during gait

rehabilitation on Earth.

3. The method provides a new tool for studying the effects of different "gravitational" levels on

gait and musculoskeletal adaptation.

Publications resulting from study

1. Whalen, R.; Hargens, A.; Schwandt, D.; and

Watenpaugh D.: Musculoskeletal Loading or

Unloading with Differential Air Pressure.

Transactions of the 37th Meeting of the

Orthopedic Research Society (ORS), vol. 16,

no. 2, 1991, p. 628.

2. Hargens. A.; Whalen, R.; Watenpaugh, D.; and

Schwandt, D.: LBNP to Provide Load Bearing in Space. Aviat. Space Environ. Med.,

vol. 62, 1991, pp. 934-937.

° Whalen, R.; and Hargens, A.: Patent 5,113,339"

Exercise Method and Apparatus Utilizing

Differential Air Pressure, 1992.

References

1. Hargens, A.; Whalen, R.; Watenpaugh, D.; and

Schwandt, D.: LBNP to Provide Load Bearing in Space. Aviat. Space Environ. Med.,

vol. 62, 1991, pp. 934-937.

2. He, J.; Kram, R.; and McMahon, T.: Mechanics

of Running Under Simulated Low Gravity. J.

Appl. Physiol., vol. 71, 1991, pp. 863-870.

3. McMahon, T.; and Cheng, G.: The Mechanics of

Running: How Does Stiffness Couple with

Speed. J. Biomechanics, vol. 23, suppl. 1,

1990, pp. 65-78.

4. Whalen, R.: Musculoskeletal Adaptation to

Mechanical Forces on Earth and in Space.

The Physiologist, voI. 36, suppl. 1, 1993,

pp. 127-130.

5. Whalen, R.; Hargens, A.; Schwandt, D.; and

Watenpaugh, D.: Musculoskeletal Loading

or Unloading with Differential Air

Pressure. Transactions of the 37th Meeting of

the ORS, vol. 16, no. 2, 1991, p. 628.

Key words

Exercise countermeasures, Hypergravity locomotion,

Hypogravity locomotion, Gait rehabilitation

H

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85
Aerogel Advanced Material Development

Investigator(s)

Susan White, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Aerogels, sometimes called "solid smoke," have the

potential for being a breakthrough material because

of their extremely light weight. They present two

problems: mechanical fragility and very high surface activity. Both of these problems were tackled

in this project. The focus of this project was to produce and investigate prototypes of two new classes

of materials: fiber-strengthened and chemically

altered aerogels, in order to explore their potential

for thermal protection system (TPS) use.

This project evolved to investigate different

materials in order to take advantage of unique, previously unexploited properties of aerogel composite

materials. The focus widened from investigating

high-temperature low-density insulation to include

other applications, in response to changes in

NASA's priorities.

Progress and results

A key question in any new approach is always

whether it will work. In the case of these

materials, it has been shown that the approach of

fiber-loading aerogels does in fact produce a

strengthened, toughened, low-density composite

material.

System investigated

• Zirconia aerogel/zirconia fiber: The first

known samples of fiber-reinforced stabilized zirconia aerogel were successfully produced for this

project by TRW's Space and Technology Group.

Twenty-five samples were produced by using a test

matrix varying the fiber-loading, chemical processmg methods and heat-treatment conditions. Fiber

loading of 12% by weight minimized the endproduct density of the samples, as shown in figure 1.

To produce sufficiently strong samples, the required

heat treatment temperatures and times have been

roughly quantified at 1350°C for 10 hours. Scanning

electron microscope (SEM) pictures of the materials

showed the microstructure.

• Chemically modified silica aerogel: To

solve the problem of the very high surface activity

characteristic of aerogels, silica aerogels were used

2.5

A 2.0

o

1.5

v

>,

"_ 1.0

C

0

C_ .5

_ _%%

m

m

1400C = 2550F/5 hrs

1300C = 23701=/10hrs

............ 1200C = 2200F/10 hrs

1100C = 2000F/10 hrs

....*.<,.".'. . .

I I I

10 20 30 40

Percent fiber loading

Figure 1. Density of the composite is minimized by

optimization.

as a testbed because the chemistry of silica is

already well understood. The approach involves

chemically bonding extra nitrogen atoms to the

hydroxyl groups bound to the aerogel structure

itself. This is accomplished by oxidizing the material, followed by nitriding aerogel bound to gaseous

phase and decomposing it thermally once it has

entered the structure. Fifteen different compositions

were produced and tested. Results also indicate that

this approach did succeed in raising the sintering

temperature of the material, reducing the contraction of the material at a given temperature. Results

indicate that high-temperature processing is

required to optimize the processing. A follow-on

phase of this investigation is in progress.

• Silica aerogel/silica fiber (currently in

progress): This development benefits from the extensive NASA knowledge base on silica fiber composites. A family of different composite materials is

currently being produced with a range of different

aerogel and fiber loading fractions.

• Zirconia aerogel/silica fiber (currently in

progress): This development includes more sophisticated processing methods than those used in the

first phase of the study. Property measurements

planned for this final set of samples include compression, Young's modulus, thermal conductivity,

and other thermal tests.

• Numerical predictions (currently in

progress): This DDF project also continues to benefit

from a related but separately funded SBIR Phase 1

project with Applied Sciences Laboratory. In that

project, a numerical model was developed to predict

the radiative transport properties of fiber/particle

composites like these materials. The predicted

86
trends show a clear advantage to having the small

aerogel particles contribute a strong shortwavelength reflectance property to the material.

Significance of the results

The goal of this project was to create and investigate a new class of lightweight, mechanically

strong insulation materials. These extremely

lightweight, low conductivity materials offer significant potential for thermal protection system

applications. Fiber-loading aerogels successfully

produce a strengthened, toughened, low-density

composite material. Chemical modification did succeed in raising the sintering temperature of a representative aerogel. The unique physical properties

and nanostructure of this novel material offer new

solutions to several insulation problems of concern to

NASA.

Publications resulting from study

Davison, William, et al.: Aerogel Materials, Final

Report for Contract No. A24127D, TRW Space

and Technology Group, Redondo Beach, Calif.

Hrubesh, L.: Enhanced Thermal Capacity Aerogels.

Summary Report for Contract No. A-26310D/

L-1342, Lawrence Livermore National Laboratory, Livermore, Calif.

White, Susan; Lee, Siu-Chun; and Grzesik, Jan:

Advanced Particulate Fibrous Composite for

Thermal Control of Re-entry Vehicles.

AIAA 93-2824, AIAA 28th Thermophysics

Conference, Orlando, Fla., 1993. Submitted to:

J. Quant. Spectros. Radiat. Trans.

Lee, Siu-Chun; White, Susan; and Grzesik, Jan:

Effect of Particle Size in Composite Materials

on Radiative Properties. AIAA 93-2729, AIAA

28th Thermophysics Conference, Orlando, Fla.,

1993. Submitted to AIAA J. Thermophysics.

Key words

Aerogel, Thermal protection materials, Composites

87
Effects of Low Energy Impact of Atomic Oxygen and

Nitrogen on Advanced Materials

Investigator(s)

Susan White, Joan Pallix, and Les Barnes,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The objective of this research is to develop experimental and computational methods that will aid in understanding the fundamental physical processes involved

in surface catalysis on thermal protection materials.

Little data have been collected on the interactions of

oxygen and nitrogen atoms with the surfaces of

advanced thermal protection materials. Catalysis data

would aid in understanding the relationships between

surface mediated atom recombination and surface

heating during vehicle reentry into the Earth's atmosphere. This is essential in the development of higher

performance and lighter weight thermal protection

systems. During the past year, research has been carried out in three areas including (1) Fourier transform

infrared (FTIR) spectroscopy, (2) laser induced fluorescence and ionization spectroscopy and (3) computational modeling of gas-surface interactions.

Progress and results

FTIR spectroscopy- Infrared measurements will track

and quantify the low-pressure temperature-controlled

desorption of surface adsorbed species including 02

on a silica substrate. These experiments will simulate

the more complex surface interactions on a reentry

vehicle surface. A porous substrate, made by chemically etching crystalline silica, has been successfully

used in related desorption experiments reported in the

literature. However, the interacting surface area can be

maximized by using an amorphous silica aerogel substrate to significantly enhance the signal-to-noise ratio.

In these experiments, the silica aerogel substrate will

be heated to 500°C for heat cleaning, then cooled to

-125°C in a low-pressure chamber. The adsorbing/

desorbing species will be introduced and allowed to

react with the extended surface of the substrate. The

temperature will then be increased to the maximum

following a programmed profile. During this phase of

the project, the experimental requirements were established and the necessary apparatus was designed and

partly procured. In the second year of the project, the

remainder of the necessary equipment will be procured and the infrared spectroscopy experiments will

be carried out.

Laser spectroscopy- A number of spectroscopic

measurements have been made at SRI International (in

collaboration with R. Copeland) in order to design

experiments which will detect O and N atoms as well

as their recombination products N 2, 02, and NO. Current experiments include room temperature detection

of O atoms as well as 02 molecules formed from surface recombination. The experimental apparatus was

designed for versatility in that it allows for either fluorescence detection or detection of ions. Laser induced

fluorescence and ionization methods can be used to

probe the internal energy (vibrational or rotational) of

the product molecules. This information will aid in

determination of energy accommodation coefficients

and atom recombination probabilities at the surface of

interest. Quartz was chosen for the initial measurements to determine the viability of the detection methods because the surface is fairly well defined and

O atom recombination on quartz has been well studied. Recombination on Cu and Ni was also briefly

investigated. Through this work we have established a

method of generating O atoms with minimal 02 background that will simplify interpretation of surface

mediated atom recombination data. All sources of

spectral interference and background interference

have been identified and minimized or eliminated for

detection of ground state 02. This experimental setup

will be useful for studies involving surface reactions

that produce 02; in addition, studies involving N2 and

NO production at the surface are also possible with

few modifications to the procedures. A final report on

this work entitled "Oxygen Atom Scattering and

Recombination Experiments" has been submitted.

Computational chemistry- An examination of the

available literature on the alpha-quartz surface has

given insight into the complicated nature of the problem of the interaction of molecules with the surface.

From both an experimental and theoretical viewpoint,

the structure of the surface of alpha-quartz and amorphous silica is important. The level of hydroxylation

(from available water molecules) of the surface will

affect adsorption significantly. Thus the current theoretical calculations are aimed at modeling the interaction of water with small silica clusters, to study

interaction energies and possibly vibrational spectra of

the adsorbed water molecules. These calculations are

88
ongoing,currentlyappliedtodifferentadsorption

geometriesfor wateronanSi(2)O(7)H(6) cluster,

whichmaybecomparedwith othertheoreticalwork

onsmallerclustersandalsoexperimental worksurface

studies.Thisworkwassummarizedin areportentitled"MethodsforStudyingtheAlpha-QuartzSurface"

byLynnAmonoftheUniversityofMichigan.

Key words

Catalysis, Atom recombination, Energy

accommodation

89
Application of Digital Signal Processing (DSP) to Near

Real-Time Compensation of Attenuated Acoustical and

Unsteady Pressure Measurements

Investigator(s)

Stephen A. Whitmore,

Dryden Flight Research Facility,

Edwards, CA 93523-0273

Objectives of the study

The measurement of high frequency acoustical/

unsteady pressure data is a difficult sensing task. The

primary difficulty in obtaining these high fidelity measurements is pneumatic distortion in the tubing used

to transmit pressure impulses from the surface to the

measurement transducer. To avoid pneumatic distortion, experiment designers seek to mount the sensor at

the measurement surface. In some cases this offers a

viable measurement solution; however, in most cases,

as when many pressures must be measured in a small

surface area or when pressure is sensed in a hostile

environment, pneumatic tubing is required to transmit

pressure from the surface to the transducer. This

tubing distorts the pressure impulses and causes a

magnitude amplification (resonance) or attenuation

and a phase delay (Berg and Tijdeman, 1965; Iberall,

1950; Lamb, 1957; Rayleigh, 1894; and Schuder and

Binder, 1959).

This research attempts to develop methods for

numerical compensation of pressure measurement

distortion induced by pneumatic tubing, which cannot

be mitigated in the instnmlentation design, i.e., the

goal is to take the acoustically distorted pressure measurements and perform inverse modeling to compensate for the effects of the distortion using analytical

models. The research proposes to apply the compensation methods in real time using digital signal processing (DSP) technology.

Progress and results

The physics of pneumatic distortion have been analyzed using one-dimensional (l-D) unsteady NavierStokes relationships. The energy equation has been

decoupled from momentum and continuity assuming

a polytropic relationship between pressure, density,

and temperature. This decoupling allows the

boundary value problem to be reduced to a simple

model, which can be solved in closed form in the

frequency domain. The model has been experimentally

verified for simple geometric configurations

(figs. 1(a-b)).

Although numerical techniques for highly

damped complex configurations have been developed

previously (Whitmore, 1988), closed form solutions

have not existed.

Deconvolution algorithms to perform the compensation have been analytically developed and verified

off line (nonreal time). Conceptually, it is a trivial

matter to compensate for the effects of the acoustical

distortion by simply inverting the transfer function

and performing the inverse transform, a method

referred to as special deconvolution.

In practice, however, the problem is not as easy.

At high frequencies where the measured signal is

attenuated considerably, the inverse of the transfer

function acts as an amplifier and will amplify both the

attenuated signal and the noise introduced into the

measurement by the transducer and its associated

electronics. This amplification tends to produce a very

noisy reconstructed signal at high frequencies.

An inversion algorithm based on the Wiener Filter

(Mendel, 1983) has been developed to circumvent this

problem. The algorithm basically weights the inverse

transfer function as a function of the signal-to-noise

power ratio of the measured pressure data. Hardware

necessary to implement the developed filtering

algorithm has been procured.

Significance of the results

The closed form analytical model allows the compensation to be performed directly using Fourier transform methods, and it does not require the solution of

partial differential equations a time consuming process that cannot be performed in real time. The development of the filtering algorithm circumvents noise

amplification problems and will allow even heavily

attenuated signals to be faithfully reconstructed up to

the noise threshold of the measurement system.

References

Berg, H.; and Tijdeman, H.: Theoretical and Experimental Results for the Dynamic Response of

Pressure Measuring Systems. NLR Report F.238,

1965.
(a)

MAGNITUDE ~ dB

5.0-

-0.0 -

-5.0 -

-10.0 -

-15.0 -

-2O.O -

-25.0 -

-30.0

1

PHASE ANGLE ~ deg

2OO

150

100

5O

0

-50

-100 -

-150

-2OO

1

1

I I I

10 2O 5O 100

Frequency ~ Hertz

200 500

I

1000

"X

10

I

2O 5O 100

I I I

200 500 1000

Frequency ~ Hertz

Signals out to

Micro-computer A/D

Test Microphone /

Solid

Titanium

Skin

10-mil

port

Flush Mount

Reference

Microphone

(b)

Figure 1. (a) Empirical validation of closed form model, (b) test configuration 0.03 in. diameter steel line with 0.010-in.

diameter port (12-16XL wing glove).

91
Iberall,A.S.:AttenuationofOscillatoryPressuresin

InstrumentLines.NationalBureauofStandards

ResearchPaperRP-2115, July1950.

Lamb,J.P.:TheInfluenceof GeometryParameters

UponLagErrorinAirbornePressureMeasurement

Systems.WADCTR57-351,Wright-PattersonAFB,

Ohio,July1957.

Mendel,JerryM.:OptimalSeismicDeconvolution,An

EstimatedBasedApproach.TheAcademicPress,

NewYork, N.Y.,1983.

Rayleigh,LordJ.:TheTheoryofSound.Seconded.,

McMillanandCompany,London,1894.

Schuder,C.B.;andBinder,R.C.:TheResponseof

PneumaticTransmissionLinestoStepInputs,

JournalofBasicEngineering,ASMETransactions,

Dec.1959.

Whitmore,StephenA.:Formulationof aGeneral

TechniqueforPredictingPneumaticAttenuation

Errorsin AirbornePressureSensingDevices.NASA

TM-100430, 1988.

Key words

Pressure sensor, Deconvolution, Digital signal

processing (DSP), Pneumatic compensation

} _i/:!x!_

_iZ

92
Technology Development for Selective Recovery of Urea

from Urine and Its Subsequent Decomposition to Ammonia

with Application in the Controlled Ecological Life Support

Systems (CELSS)

Investigator(s)

Richard Wisniewski, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Jeff Chamberlain, University of California,

Berkeley, CA 94720

Objectives of the study

Develop a technology for separation of urea and salts

from urine. Urea will be a major component of the

nitrogen balance loop and will be used as fertilizer for

plants in CELSS.

Progress and results

The applied separation principle is based on the fact

that in the aqueous solution salt molecules dissociate

completely into ions and urea molecules dissociate

very little. Application of an electric field would cause

a movement of the salt ions and might have only a limited effect on the urea molecules. Diffusional effects

may not affect this separation in a significant way

since the diffusion coefficient of a urea molecule is of

similar magnitude to salts. The electric field is a dominant separation driving force, and a transport flux in

an electric field can be several hundred times that due

to diffusion. In a free-flow electrophoresis apparatus, a

thin layer of flowing liquid is subject to a perpendicular electric field. After injecting a sample in the center

of a stream, urea will be collected from the outlet central area, and salt ions that migrate toward the electrodes will be collected on both sides. The urea

molecule H 2NCONH 2 forms hydrogen bonds with the

surrounding water molecules. Ions have their own

hydration shells that are dragged during ion movement. Movement of ions in an electric field may affect

the urea molecules and their associated water. Positive

and negative ions would have hydration shells with

differently oriented water molecules and might interact differently with the urea hydration shell. These

assumptions might be confirmed experimentally by

showing how the moving ions with different mobilities and hydration shells could affect the distribution

of urea molecules originally introduced as a narrow

band.

Methods for urea detection and ion determination

in aqueous solutions have been developed. The urea

detection method employs enzyme urease that converts urea to ammonia. The same enzyme will be used

to convert a stream of separated urea into ammonia in

a controlled manner. Electrophoretic power supplies, a

multichannel peristaltic pump with extended head

and cassettes, and a recirculating cooler have been

selected and purchased. Two small batch electrophoretic cells were designed and tested. An in-house

design of a continuous flow electrophoretic chamber

has been built. A precision free-flow electrophoresis

chamber has been purchased from Dr. Weber GmbH.

It arrived in August 1993. Some originally missing

components arrived in September 1993. A capillary

flow electrophoresis apparatus has been purchased

from Isco and arrived in September 1993.

The first stage of this study involved testing the

separation process and possible intermolecular effects

during electrophoresis in a free solution. Nine experiments were performed using the batch electrophoretic

chamber (fig. 1) with manual sample injection and

withdrawal. After each experiment, the separation

weirs were lowered to divide liquid volume prior to

sampling. The observed increase of electric current

during each run has been an indication of ionic migration. Figure 2 shows the distribution of urea and ions

(a) and the distribution of pH (b) when a sample containing urea and high concentration salts was injected

into a buffer with low salt concentration. Figure 3

shows the urea distribution when urea only was

injected into the same buffer. Initial and final levels of

the electric current are shown as Io and If. Analytical

grade urea and sodium phosphate were used for

preparation of solutions.

Significance of the results

Results indicate that there may be a molecular interaction involved among the urea molecules, ions migrating in an electric field, and hydrating water molecules.

The final urea band is wider in the case of higher salt

concentration (fig. 2(a)). At higher salt concentrations

more ions move through the bulk water and widening

of the urea band occurs because of their apparent

interaction with urea molecules.

At high electric currents the phenomena of thermal convection and electroosmotic flow may also contribute to band spreading. Use of the manual sampling

technique may result in some minute back flows of

liquid during sampling, further spreading the urea

band. In the free-flow electrophoresis with

93
_r

145

110

_ _ _ weir Sparation ! i _.. i i!ii!t

Separation

membrane

:---_- _ Center _/////////////] ; //_/

Electrode

Figure 1. The cross section of batch electrophoretic chamber (width = 100 mm; all dimensions in mm).

2000

A

E

Q.

r0

= 1000

LC

O

¢.-

O

(J

(a)

(a)

-i-+

Urea (ppm)

Sodium (ppm)

---'BI"'- Phosphate (ppm)

12

10

8 _- _Buffer: Na2HPO4

| /concentr. 0.172 g/L

zD. _- l_ Sample (2 mL):

| /- " Na2HPO4:43 g/L

6 F // urea:134g/L

_- / 360 V DC

4 | / ][o = 54 mA

Center -- _ _ ++ + Center

Zone (b) Zone

Figure 2. (a) Urea and ion distribution, (b) pH distribution.

94
i ili...... _i_i'

_iii_ i!i_ii_ ,:

!__i•i_

ii!!_ii_ _ _i:i

,i_ii_:!i

_i_ _ii iii_i!i II_ i_

i i i_

6000

5000

4OO0

[

3000

2000

lOOO

o I I i ! ! I

++ + Center - - -

Zone

_ Buffer: Na2HPO4 _]

concentr. 0.172 g/L / \

Sample (1 mL): / \

urea: 268 g/L / _

360v oc / \

Io = 22 mA / \

I=

I I I

Figure 3. Distribution of urea with low salt buffer.

well-controlled laminar flow, a continuous sampling

and wall cooling would eliminate some of these

problems. In the free-flow electrophoresis process, salt

concentration in a carrier buffer and a sample would

be optimized for best separation. Lower concentration

of salt had a positive effect on separation resolution

(fig. 3).

There is a pH distribution phenomenon across the

chamber (fig. 2(b)) caused by reactions near electrodes.

The pH distribution may be controlled by adjustments

in a main buffer composition. The electrode zones can

be separated from the main chamber by various membranes (ultrafiltration, microfiltration, or dialysis type)

to further minLrnize the electrode effects.

A molecular modeling approach may be tried for

modeling the urea molecule with its hydrating shell

and the ions (salts) with their hydrating shells to aid in

better understanding how those shells might interact.

A longer batch chamber with more partitions to be

used for detailed investigations of urea band spreading effect is in a design stage. Electrophoretic separation phenomena will be further studied using the freeflow and capillary electrophoresis systems. A process

of enzymatic hydrolysis of separated urea would

complete the project.

Publications resulting from study: None so far

References

Amo, K.: Human-Urine Analog and ASPEN Plus

Model for Test-Stands and ASPEN Plus Computer

Simulation Programs. NASA Ames Research Center, Advanced Life Support Divison Internal

Report, Feb. 1992.

95

Andrews, A.: Electrophoresis. Second ed., Clarendon

Press, Oxford, 1990.

Andrews, G.; and Fonta, J.-P.: The Engineering Design

of Continuous Electrophoresis. Electrophoresis,

vol. 6, 1985, pp. 483--488.

Bockris, J.; and Reddy, A.: Modem Electrochemistry.

Plenum Press, New York, 1977.

Conway, B.: Ionic Hydration in Chemistry and Biophysics. Elsevier, Amsterdam, 1981.

Cristinziano, P.; Lelj, F.; Amodeo, P.; Barone, G.; and

Barone, V.: Stability and Structure of Formamide

and Urea Dimers in Aqueous Solution. J. American

Chem. Soc., Faraday Trans. 1, vol. 85, no. 3, 1989,

pp. 621-632.

Crow, D.: Principles and Applications of Electrochemistry. Chapman and Hall, London, 1988.

DeKock, R.; and Gray, H.: Chemical Structure and

Bonding. University Science Books, Mill Valley,

Calif., 1989.

Geankoplis, C.; Okos, M.; and Grulke, E.: Diffusion of

Urea and Potassium Chloride in Albumin Solution.

J. Chem. Eng. Data, vol. 23, 1978, pp. 40--44.

Hanning, K.; and Heidrich, H.-G.: Free-Flow Electrophoresis. GIT Verlag GmbH, Darmstadt,

Germany, 1990.

Jorgenson, J.; and DeArman, Lukacs K." High-Resolution Separations Based on Electrophoresis and

Electroosmosis. J. Chrom., vol. 218, 1981,

pp. 209-216.

Nath, S.; Schutte, H.; Hustedt, H.; and Deckwer, W.-D.:

Application of Continuous Zone Electrophoresis to

Preparative Separation of Proteins. Biotechnol.

Bioeng., vol. 42, 1993, pp. 829-835.

Neilson, G.; Broadbent, R.; Howell, I.; and Tromp, R.:

Structural and Dynamical Aspects of Aqueous Ionic

Solutions. J. American Chem. Soc. Faraday Trans.,

vol. 89, no. 16, 1993, pp. 2927-2936.

Rhodes, P.; Snyder, R.; and Roberts, G.: Electrohydrodynamic Distortion of Sample Streams in Continuous Flow Electrophoresis. J. Colloid Interface Sci.,

vol. 129, 1989, pp. 78-90.

Righetti, P.; Van Oss, C.; and Vanderhoff, J., eds.:

Electrokinetic Separation Methods, Elsevier,

Amsterdam, 1979.

Schmitz, K.: Macroions in Solution and Colloidal Suspension. VCH, Weinheim, 1993.

Tanaka, H.; Touharo, H.; Makanashi, K.; and

Watanabe, N.: Computer Experiment on Aqueous

Solution. IV. Molecular Dynamics Calculation on

the Hydration of Urea in an Infinitely Dilute Aqueous Solution with a new Urea-Water Pair Potential.

J. Chem. Phys., vol. 80, no. 10, 1984, pp. 5170-5186.

Key words

Separation in electric field, Free-flow electrophoresis,

Salt-urea separation.
MIR Study of Disks Around Young Stellar Objects

Investigator(s)

Fred Witteborn, Ames Research Center,

Moffett Field, CA 94035-1000

Harold M. Butner, DTM-Carnegie Institute,

Washington, D.C. 20015

Other personnel involved

Lynne Deutsch, University of Massachusetts,

Amherst, MA 01002

Diane Wooden, Ames Research Center,

Moffett Field, CA 94035-1000

Antonella Natta, Osservatorio di Arcetri,

Firenze, Italy

Objectives of the study

Understanding the circumstellar environment of

young stars is one of the major areas of research in star

formation today. Current theories suggest that disks,

which might serve as sites for planet formation, are

quite common. However, our understanding of disk

properties, and how the disk is related to the more

extended young stellar object environment, is quite

limited. We had two major objectives. The first was to

develop a radiative transport code that would allow us

to model both the disk and the more extended envelope around a young star. In particular, we wanted to

have a code that allowed us to vary the disk properties

and explore a range of physical conditions. Second, we

planned to obtain midinfrared spectral data using the

Ames Hi-Resolution Faint Object Spectragraph for a

variety of sources. These data would be combined

with far-infrared, submillimeter and millimeter data.

The data would be used to constrain source models.

From these source models, we would then test

current ideas of star formation. For example, are all

sources consistent with the idea of a simple infalling

zone? Are more complex density gradients found, and

under what conditions? Is there a correlation between

the young stellar mass and the disk properties? Only

by building up a large sample of source models can

these questions be addressed. Studies of so few objects

leave open the possibility that the particular source is

somehow unique.

Progress and results

1. Disk code: We have produced a very flexible,

simple disk code for use with our radiative transport

code. The disk portion of the radiative transfer is not

self-consistent, but it does conserve luminosity. It

assumes a power law temperature distribution, and it

handles the reprocessing of the central star's radiation

field. The output from this code can be directly input

into the spherical envelope radiative transport code.

By adopting the average radiation field from the disk,

we can estimate the disk's effects on the envelope. By

an iteration process, we have also included the

envelope's heating on the disk. The backwarming of

the disk by the envelope has important consequences

for estimates of the total disk mass because the disk

mass is most easily estimated from the total millimeter

flux. However, backwarming allows a disk to become

warmer than expected at its outer portions, and thus to

require a smaller disk to produce the same millimeter

flux.

Z MIDIR Observations: We have obtained some

spectra of T Tauri stars, and some preliminary observations of Vega-like stars. T Tauri systems are low

mass young stars, similar to our own Sun in mass.

Vega-like stars are stars that are on the main sequence

but seem to have debris disks around them. The debris

might be failed planets or just material that never

condensed. Both systems have implications for our

understanding of star formation. We have only just

begun studying the data, but it is quite promising. In

addition, we have an active program to obtain more

spectra using the Ames Hi-Resolution Faint Object

Spectragraph (HIFOGS). We will be observing at

Mount Lemmon in February 1994 and at the Infrared

Telescope Facility (IRTF) in June 1994.

We have also expanded the program to include

midinfrared imaging. By studying the midinfrared

•spatial distribution and comparing it with far-infrared

maps, we can estimate the envelope structure much

more precisely. In addition, by careful mapping at

selected wavelengths, we can deduce the dust properties in the envelopes and look for possible variations

between different stars. Such changes would reflect

different heating histories and evolutionary paths.

3. The program has now received support from

the NASA Origins of the Solar System program. Costs

of observing will be supported primarily by that program in the future.

Significance of results

We have modeled several sources in detail and have

demonstrated that our technique can place strong constraints on the disk and envelope properties. We will

be able to provide a large sample of source models in

the next two to three years. This large sample offers

96
theopportunityto directlycomparestarformation

modelswithactualsourcesin astatisticallymeaningful way.In addition,ourresultsarealreadyrevealing

asystematicdifferencebetweenlowmassstarsforminginrelativeisolationandhighermassstars.Thelow

massstarsseemtohaveenvelopeswhoseproperties

areinagreementwithcurrentexpectionsfromtheoreticalconsiderations. Thehighermassstarshavemuch

shallowerdensitygradientsandwouldappearto

requireadditionalphysicalprocessestoexplainthe

observations.

Publications resulting from study

A number of papers have resulted from the work thus

far, and more are anticipated over the next year or so.

The initial project has greatly expanded as a result to

include a large range of young stellar objects.

References

Butner, H. M.; Di Francesco, J.; Evans, N. J.; Harvey,

P. M.; Mundy, L. G.; and Natta,A.: Density Profiles

of Envelopes Surrounding Herbig Ae/Be Stars. The

Nature and Evolutionary Status of Herbig Ae/Be

Stars, P. S. Phe, M. Perez, and J. P. E.

Vandenheuvel, eds., Astron. Soc. of the Pacific,

1994, in press.

Butner, H. M.; Natta, A.; and Evans, N. J.: Spherical

Disks: Moving Towards a Unified Source Model for

L1551. Ap. J., vol. 420,1994, p. 326.

Deutsch, L. K.; Butner, H. M.; Hora, J. L.; Hoffman,

W. F.; Fazio, G. G.; and Shivanandan, K.: Investigating the Circumstellar Environments of YSOs

Through Mid-IR Imaging. BAAS, vol. 24, 1992,

p. 1287.

Natta, A.; Palla, F.; Butner, H. M.; Evans, N. J.; and

Harvey, P. M.: Infrared Studies of Circumstellar

Matter Around Herbig Ae/Be and Related Stars.

Ap. J., vol. 406, 1993, p. 674.

Key words

Disks, Star formation, Midinfrared observations

97
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Predicting Lyme Disease Risk: A Remote Sensing Model

Based on Landscape Epidemiology

Investigator(s)

Byron L. Wood, James G. Lawless,

Louisa R. Beck, and Sheri W. Dister,

Ames Research Center,

Moffett Field, CA 94035-1000

Durland Fish, New York Medical College,

Valhalla, NY 10595

Objectives of the study

Lyme disease is one of the most prevalent and rapidly

increasing vector-borne diseases affecting humans in

the United States and northern temperate regions of

the globe. In 1991, 9,465 cases were reported in the U.S.

Field studies by investigators at the Medical Entomology Laboratory (MEL) in Westchester County, New

York, have shown that tick populations and canine

seroprevalence rates (CSR, a measure of Lyme disease

exposure) vary along an urban-to-rural gradient. This

gradient can be described in terms of landscape

features, such as woodlands and residential developments with high-, medium-, and low-density vegetation, which are likely locations for contact between

humans and infected ticks. The goal of this research is

to develop a remote sensing-based spatial model to

describe key landscape features associated with the

vector and hosts of Lyme disease, and therefore predict areas where humans are at greatest risk of getting

the disease.

Progress and results

The results of the 1992 comparison between CSR,

landscape composition, and the ratio of deciduous to

residential-dense vegetation properties were used to

create a Lyme disease risk map of Westchester County.

During 1993, previously acquired Landsat Thematic

Mapper (TM) data were reprocessed to create an

improved map of the landscape composition along the

urban-to-rural gradient in the study area. In 1993,

research also focused on (1) the use of additional field

datasets to refine this risk map to the property level,

and (2) the extension of the techniques developed in

Westchester County to a regional scale. Raw TM data

(with 30-m spatial resolution) were spatially and spectrally degraded to simulate 80- and 1,100-m data for

use at regional scales. The three datasets (30-, 80-, and

1,100-m) were then used to generate a vegetation

index map of the urban-to-rural gradient. It was found

that the relationship between CSR and the ratio of

deciduous forest and residential-dense vegetation

properties was maintained at all scales. Additional

field datasets on human cases, tick populations, and

residential landscape composition have been

integrated into the geographic information system

(GIS) database for spatial analysis and correlated with

CSR and landscape composition.

Significance of the results

The results of the remote sensing and GIS studies indicate that it is possible to generate a Lyme disease risk

map at the municipality, county, and regional level.

The dataset on tick abundance data will be used to

study the size, shape, and spatial context of landscape

elements that influence disease transmission risk.

FY94 research

Funding for this DDF investigation ended on

September 30, 1993. Work will, however, continue

for approximately two more months in order to

complete all tasks outlined in the initial proposal. A

follow-on proposal has already been submitted to the

U.S. Agency for International Development and work

has begun on a second collaborative proposal between

NASA and the National Institutes of Health and

Centers for Disease Control.

Publications resulting from study

Dister, S. W.; Beck, L. R.; Wood, B. L. ; Falco, R.; and

Fish, D.: The Use of GIS and Remote Sensing

Technologies in a Landscape Approach to the Study

of Lyme Disease Transmission Risk. Proceedings,

Seventh Annual Symposium on Geographic

Information Systems in Forestry, Environmental,

and Natural Resource Management, Vancouver,

B.C., Feb. 15-18, 1993.

References" None so far

Key words

Remote sensing, Geographic information systems, Risk

map

98
APPENDIX

For each of 48 projects sponsored in FY 1993, a brief description and the financial distribution and status follow.

The reports are arranged alphabetically by the last name of the first investigator.

99

....7 _ .......................... 7-. I "i: .............

NASA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Laboratory Investigation of the Growth, Structure, and Apparent Phase Equilibria of Polar

Stratospheric Clouds

Investigator(s) (show affiliation) David F. Blake, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

FY93 Expected completion date

0 Authorized in FY93

$40,000 (Estimated)

$40,000

Requested for FY94, if any

FY94

$40,000

$371000

Status of study I-] Completed in FY93

If continued in FY94 r-I with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

_] Continued in FY94

IX;'] with FY94 funds?

to Other (identify)

Purpose of investigation

The chlorofluorocarbon (CFC)-induced depletion of ozone in the polar stratosphere is known to involve heterogeneous chemical reactions on polar stratospheric cloud particles. The purpose in this investigation is to identify the phases

that exist within polar stratospheric cloud ice particles by forming analog ices under the same conditions and studying

their structure. We hope that the results will help to clarify important issues such as the reason for the expansion of the

Antarctic ozone hole, the likelihood of an Arctic ozone hole, or the possibility that observed ozone depletions above the

midlatitudes will persist or become widespread.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

The first year has been spent building an apparatus to deposit polar stratospheric cloud analog ices onto electron

microscope grids for analysis. The apparatus is nearly complete. In the second year of the project, a series of experiments

will be conducted to identify the phases present by analyzing the analog materials in an electron microscope.

Prepared by David F. Blake Org. Code SSX MS 239-4 Phone (415) 604-4816

PAGE INTENTIONALLYBLANK 101

__ __GE _t.At_ /_YT FKf_,_I_
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation The Preservation of Organic Matter in Hot Spring Deposits: Developing Search Strategies for a Fossil

Record on Mars

Investigator(s) (show affiliation) David F. Blake, Ames Research Center, Moffett Field, CA 94035-1000;

Jack Farmer, SETI Institute, Mountain View, CA

Funding

Total prior to FY93

Year Initiated FY93 Expected completion date

0 Authorized in FY93 $40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated)

$40,000

Requested for FY94, if any

FY94

$40,000

Status of study I--I Completed in FY93 IX;']Continued in FY94

If continued in FY94 17 with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

Images of Mars show morphological features that are thought to be due to the flow of liquid water. This observation,

along with theoretical considerations, has led scientists to conclude that Mars had an early wet and warm period, similar

to that of Earth. During this period, life may have developed on Mars just as it did on the Earth. One environment that

could have harbored early life on Mars (and also could have preserved fossil evidence of it) is silicadepositing hot springs. However, there are very few if any macroscopic clues to the biogenicity of the materials preserved within ancient hot spring sinter.

We are using state-of-the-art electronic microscopic techniques to characterize the style and extent of preservation

(e.g., taphonomy) of biological materials within hot spring deposits on Earth. Materials collected for study include

complete suites of samples from modem, near-recent, and ancient hot springs sinters. The results from this study will be

used to devise a strategy for searching for fossil evidence of early life on Mars.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

We anticipate that an ion-thinner, which as been in the procurement process for some time, will be in the lab by midDecember. We have practiced the sample preparation and analysis techniques by doing some limited ion-thinning offsite. In the next year we will be able to perform analyses of real materials and identification of biogenic features within

fossilized materials. A mineralogy student from the University of California at Berkeley will be arriving in early 1994 to

begin an NRC postdoctoral fellowship associated with this project.

Prepared by David F. Blake Org. Code SSX MS 239-4 Phone (415) 604-4816

102
iiill _

i!!ii!iiiiiiii!iiiill -

/!il _i!i_

iiiiiii !_,i_'

ii _

....!i!i!_iilil _

_ii:_ i _

•_i i! _ : :

i _iii

!_i__

iii_I!filliii

ii!!_i!i _i!_iiill_

iiiili _ ̧:!iili:i:ii/ilii!i

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Human Exploration Demonstration Project (HEDP)

Investigator(s) (show affiliation) Edward Chevers and David Korsmeyer, Ames Research Center,

Moffett Field, CA 94035-1000

Funding Year Initiated FY91

Total prior to FY93 $467,000

Total expended in FY93: $310,000 (Estimated)

In-house $267,000

Contracts (identify) $43,000 (Bionetics)

Grants (identify)

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY94

$310,000

$1401000

Status of study Completed in FY93 _r] Continued in FY94

If continued in FY94 I-7 with funds remaining?

If transitioned to other funding, to RTOP (number?)

PX] with FY94 funds?

to Program (name?) to Other (identify)

Purpose of investigation

To develop a technology testbed based on ARC-specific systems and capabilities relating to planetary exploration.

The implementation is a series of demonstrations showing the synergism between technologies and emphasizing

collaborative systems development.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

None

Prepared by David Korsmeyer Org. Code FI MS 269-1 Phone (415) 604-3114

103
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Development of Fiber-Optic Acoustic Sensors for Wind Tunnel Applications

Investigator(s) (show affiliation) Young C. Cho and Paul T. Soderman, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

$60,000 Authorized in FY93

$20,000 (Estimated) Requested for FY94, if any

FY94

$20,000

Status of study 1---]Completed in FY93 Continued in FY94

If continued in FY94 with funds remaining? [--] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To develop advanced acoustic sensors for wind tunnel applications, with minimized interference noises such as

flow-sensor interaction noise, flow induced sensor vibration, wind noise, etc. These interference noises strongly affect

currently existing acoustic sensor techniques.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

NASA's first fiber-optic microphone was developed and fabricated in a breadboard form. This sensor is multiplexed with

two sensor heads, each made of single mode fiber wrapped around a circular cylinder of styrofoam or a torpedo-shaped

aluminum body. Extensive laboratory tests are in progress for evaluation of its acoustic characteristics including acoustic

sensitivity, dynamic range, frequency response, etc. Preliminary test results demonstrated successfully its feasibility for

aeroacoustic measurements. Two papers were produced:

1. Cho, Young C.: Fiber-optic Interferometric Acoustic Sensors for Wind Tunnel Applications. SPIE Proc., vol. 1795,

1992, pp. 16-27.

2. Cho, Young C.; and Soderman, Paul T.: Fiber-optic Interferometric Sensors for Measurements of Pressure Fluctuations: Experimental Evaluation. AIAA Paper 93-0738, 31st Aerospace Sciences Meeting, Reno, Nev, Jan. 11-14,1993.

Planned future work

Laboratory calibration is being performed to study and quantify environmental effects on the fiber-optic microphone.

New fiber-optic sensor heads will be designed and fabricated for more vigorous tests in anechoic chambers and wind

tunnels. Successful completion of the wind tunnel tests will be followed by the development of a dual sensor for simultaneous measurements of pressure and temperature.

Prepared by Young C. Cho Org. Code FIC MS 269-3 Phone (415) 604-4139

104
i:_iii  ̧•

i! _ _ _7::,

_ _ _ii_ _

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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation A Prototype Infrared Gas Analyzer for Characterizing Plant Growth During Space Flight

Investigator(s) (show affiliation) James Connolly, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93 $40.000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

FY92

(Estimated)

$40,000

Expected completion date

Authorized in FY93 $40,000

Requested for FY94, if any

FY93

Status of study PX] Completed in FY93 I-"1 Continued in FY94

If continued in FY94 1-7 with funds remaining? I-"l with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

Accurate and reliable measurement of CO 2 and water vapor is critical for characterizing photosynthesis and transpiration of green plants in space. All food production, air revital_ation, and water purification functions of plants depend

on proper function of photosynthesis and transpiration. Current CO 2 analysis technologies used in ground-based laboratories have several characteristics that would severely restrict and limit their reliable and safe use in space flight. The

analyzer design developed here utilizes alternative component technologies and the operation approaches to address

each of the limitations and safety problems present in current instrumentation.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

The efforts of the past year resulted in the identification of various subsystems and the design and construction of a

breadboard CO 2 analyzer unit to allow experimentation with different components and analyzer configurations. Feasibility

studies indicated that a miniature infrared (IR) laser as well as a special type of high energy flash bulb may be used as alternate IR radiation sources in CO 2 gas analyzers. The project studies also identified specific miniature diode requirements to

allow their development. Also project efforts have initiated process for a joint effort between NASA and commercial companies to develop technology that is mutually beneficial. Successful implementation of either of the alternate IR radiation

sources will eliminate the use of traditional mechanical choppers or beam splitters.

The characteristics and performance of the IR radiation sensing subsystem, currently designed, will meet design requirements. Digital signal processing (DSP) methods may also allow simultaneous multiple gas concentration measures.

Planned future work

To encourage the development of the IR laser diode, the gas filled flash bulb, and unique radiation measurement

approaches, efforts were placed in the area of technology transfer. The goal is to use commercial funds in exchange for

marketable technology developed by NASA. To accomplish our goal a Joint Sponsored Research Program (JSRP) has

been initiated. The JSRP is currently being managed by the American Technology Institute (ATI). ATI is responsible for

researching the industry and assisting with the transfer technology to commercial companies in exchange for developrnent funds. A JSRP proposal has been completed and will be released to selected companies by ATI.

Prepared by David Bubenheim Org. Code SAR MS 239-11 Phone

(415) 604-3209

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105
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Origins of Planetary Systems: Observations and Analysis

Investigator(s) (show affiliation) Kent Cullers, Ames Research Center, Moffett Field, CA 94035-1000

Laurance Doyle, SETI Institute, Ames Research Center, Moffett Field, CA 94035-1000

Funding

Total prior to FY93

Year Initiated FY92 Expected completion date

0 Authorized in FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$38,000 (Estimated) Requested for FY94, if any

FY93

Status of study Completed in FY93

If continued in FY94 ['-] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

I--I Continued in FY94

I--] with FY94 funds?

to Other (identify)

Purpose of investigation

Pave the way for extra solar-planetary detection from Earth-based medium-sized telescopes.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

Continue with program if funding can be found.

Prepared by Laurance Doyle Org. Code SI MS 244-11 Phone (415) 604-1372

106
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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Monitoring Global Change During the Last 10,000 Years

Investigator(s) (show affiliation) Hector L. D'Antoni, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY93

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$30,000 (Estimated)

$30,000

Expected completion date

Authorized in FY93 $30,000

Requested for FY94, if any

FY94

$40,000

Status of study r-] Completed in FY93 IK'-I Continued in FY94

If continued in FY94 r-] with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To link modem pollen data and remote sensing data of vegetation to calibrate environmental data as monitored by

satellite remote sensing. Use resulting models in hindcasting past climate change and provide a larger window for

predictive models of climate change.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Communication and poster at the 26th meeting of the American Association of Stratigraphic Palynologiests, 1993.

D'Antoni, H.; and Spanner, M.: Remote Sensing and Modem Pollen Dispersal in Southern Patagonia and

Tierra del Fuego (Argentina): Models for Palaeoecology. Grana, vol. 32, Stockholm, 1993, pp. 29-39.

D'Antoni, H.: Paleotemperatures of La Malinche: A Palynological Hypothesis. Grana, Stockholm (in press).

Planned future work

Continuation of the research plan. Extension of the study of effects of increased UV-B radiation on vegetation.

Prepared by Hector L. D'Antoni Org. Code SGE MS 239-20 Phone (415) 604-5149

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107
fU/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Schmidt-Cassegrain Long-Range Laser Velocimeter

Investigator(s) (show affiliation) Stephen E. Dunagan, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

FY93

$37,000 (Estimated)

$37,000

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY94

$37,000

$38,000

Status of study I-l Completed in FY93

If continued in FY94 r--] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

Continued in FY94

IX] with FY94 funds?

to Other (identify)

Purpose of investigation

This investigation is designed to develop a new long-range laser velocimeter instrument that will provide multiapplication support to aerodynamic wind tunnel studies conducted in the NFAC 40 x 80 wind tunnel. The instrument

incorporates new technologies including high acuity telescope optics, fiber optics for both laser beam and signal transmission, and digital signal processing to enhance data rate and accuracy.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

The study has resulted in a viable instrument design utilizing the above mentioned technologies. A proof-of-concept

demonstrator configuration has been assembled and tested in the optics laboratory. A prototype instrument for the wind

tunnel is presently being fabricated, with the intention of deploying it on the High Speed Research Test in November, 1993. A

meeting paper is being prepared that describes the instrument design and operation with completion dependent on wind

tunnel test results.

Planned future work

Additional tasks remaining in the instrument assembly plan include: upgrading optical and signal processing

components to provide two-component measurement, designing and fabricating a two-dimensional traverse to provide

full two test section access, and investigating the potential for improved signal processing using digital autocorrelation

techniques.

Prepared by Barbara Rench Org. Code FFR MS T-042 Phone (415) 604-4023

108
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N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Investigation of the Scales of Turbulence in Hypersonic Rarefied Flow

Investigator(s) (show affiliation) William J. Feiereisen, Ames Research Center, Moffett Field, CA 94035-1000

Donald Baganoff and Sanjiva Lele, Stanford University, Stanford, CA 94305

Funding Year Initiated

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000

FY92

$40,000 (Estimated)

$40,000 Stanford

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY94

$40,000

Status of study I--I Completed in FY93 IX] Continued in FY94

If continued in FY94 El with funds remaining? r-] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To determine, for the case of intense turbulence in a rarefied flow, whether the predictions of the Navier-Stokes

equations agree with the predictions of a particle simulation; and, if they differ, how they differ and what impact it has

on the process of modeling turbulence by use of the Navier-Stokes equations. Three questions are being investigated:

(1) Can turbulence exist under conditions corresponding to high speed flight in the upper atmosphere? (2) Do the dissipation length scales become of the same order of magnitude as the mean free path and what implication would this have

for the modeling of these scales? (3) Can a Monte-Carlo simulation method be used to produce a direct simulation of

turbulent flow under rarefied conditions?

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Goswami, A.; Baganoff, D.; Lele, S.; and Feiereisen, W.: A Comparative Study of Turbulent Decay Using Navier-Stokes

and Discrete Particle Simulations. 45th Annual Meeting, Fluid Dynamics Division, American Physical Society, Florida State

University, Nov. 22-24, 1992.

Planned future work

None

Prepared by William J. Feiereisen Org. Code RTA MS 230-2 Phone (415) 604-4225

109
N/KSA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Analytical and Experimental Studies of Rotorcraft Vertical Climb Performance

Investigator(s) (show affiliation) Fort F. Felker, Ames Research Center, Moffett Field, CA 94035-1000;

Robert M. McKillip, Continuum Dynamics, Inc., Princeton, NJ 08543

Funding

Total prior to FY93

Year Initiated FY92

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

$40,000 Authorized in FY93

$28,500 (Estimated)

$28,500

Requested for FY94, if any

FY94

$40,000

$40,000

Status of study r-] Completed in FY93 IX] Continued in FY94

If continued in FY94 _-I withfunds remaining? I'] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

Develop accurate analytical methods for the prediction of rotorcraft performance in vertical climb. An accurate set of

experimental data was acquired to support the analysis development.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None. A paper describing the research results will be presented at the 1994 Forum of the American Helicopter Society.

Planned future work

Complete the paper documenting the research results and present the paper at the 1994 Forum of the American

Helicopter Society.

Prepared by Fort F. Felker Org. Code FFR MS T-12B Phone (415) 604-6096

110
NASA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Continuous-Flow Apparatus for Studies of Gas- and Liquid-Phase Adsorption Dynamics

Investigator(s) (show affiliation) John E. Finn and Sanford S. Davis, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93 $40,000

Expected completion date

Authorized in FY93

FY93

$40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated)

$40,000

Requested for FY94, if any

Status of study [El Completed in FY93 ['7 Continued in FY94

If continued in FY94 [-7 with funds remaining? [--I with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

Design, assemble, and test an apparatus for validating theory and simulation cost for gas- and liquid-phase adsorption column models for life support system applications.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Apparatus currently applied to issues in carbon dioxide removal from cabin air.

Planned future work

Continued work on validation of computer models, and publication of results.

Prepared by John E. Finn Org. Code SAR MS 239-11 Phone (415) 604-1028

111
IW A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Development of Modal Filtering Techniques for Online Estimation of Structural Vibration

Parameters

Investigator(s) (show affiliation) Lawrence C. Freudinger, Dryden Flight Research Facility, Edwards, CA 93523-0273

Funding Year Initiated FY92

Total prior to FY93

Expected completion date

$40,000 Authorized in FY93

Total expended in FY93: $40,000 (Estimated)

In-house $15,000

Contracts (identify) $25,000

Grants (identify)

Requested for FY94, if any

Status of study _-I Completed in FY93 I-] Continued in FY94

If continued in FY94 r--] with funds remaining? r--i with FY94 funds?

If transitioned to other funding, to RTOP (number?.) 505-68

to Program (name?) Flight Test Techniques to Other (identify)

Purpose of investigation

To develop a theory known as discrete modal filtering for the purpose of observing the vibration characteristics of

mechanical systems.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Computer upgrades were made to allow the research to proceed without hindering other computer users. Software was

purchased, including data acquisition control libraries. Boeing has contracted with the University of Cincinnati to investigate

the performance of modal filters during the ground vibration tests of the B-777. Successful results will subsequently lead to

flight test application. Teledyne Ryan has expressed interest in using an online estimation tool concept that was proposed by

the principal investigator. This interest resulted in an unsolicited proposal from Structural Dynamics Research Corporation to

implement modal filtering as an option in their currently available software for data acquisition. Funding procedures for the

unsolicited proposal have been initiated.

Planned future work

Modal filtering is a data condensation tool that will aid in the development of online tools for data processing.

Sufficient interest has been generated to make non-DDF funding sources available. These other sources will be pursued.

Future work will include development of test methodologies that use modally filtered data. Theoretical aspects wig

continue to be investigated. In addition, several individuals in academia have begun to incorporate modal filters into

their efforts. It is hoped that well-conceived algorithm development combined with appropriate commercialization

efforts will eventually result in a panacea for health monitoring of certain vibrating mechanical systems such as aircraft.

Prepared by Lawrence C. Freudinger Org. Code XRDV MS 4840D Phone (805) 258-3542

112
I IASA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Computational Modeling of Femtosecond All-Optical Switches Directly from Maxwell's Equations

Investigator(s) (show affiliation) Peter M. Goorjian, Ames Research Center, Moffett Field, CA 94035-1000

Allen Taflove, Northwestern University, Evanston, IL 60208

Funding Year Initiated FY91

Total prior to FY93

Expected completion date

$40,000 Authorized in FY93

Total expended in FY93: $40,000 (Estimated)

In-house $15,000

Contracts (identify)

Grants (identify) $25,000 NCA2-827

Requested for FY94, if any

FY93

$40,000

Status of study i"-] Completed in FY93 [_ Continued in FY94

If continued in FY94 with funds remaining? I-] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

Develop algorithms and computer codes for modeling all-optical switches and semiconductor lasers with the fullvector nonlinear Maxwell's equations

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Planned future work

1. Continue code development for all-optical switches

2. Develop code for semiconductor lasers

Peter Goorjian RFC Prepared by Org. Code MS T047-1 Phone (415) 604-5547

113
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Tension and Compression Effects of Cell Behavior

Investigator(s) (show affiliation) Rosalind A. Grymes and Christine Sawyer, Ames Research Center,

Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

$40,000 Authorized in FY93

$40,000 (Estimated)

$40,000

Requested for FY94, if any

FY93

$40,000

Status of study Completed in FY93 Continued in FY94

If continued in FY94 [--7 with funds remaining? IX;'] with FY94 funds?

If transitioned to other funding, to RTOP (number?) 199-40-22-01

to Program (name?) Space Biology to Other (identify)

Purpose of investigation

This investigation was designed to:

• acquire and instantiate the use of an instrument that provides a mechanically active environment of uniaxial

tension and/or biaxial compression on growing cultures of mammalian cells

• demonstrate the effect of applied uniaxial tension on the growth patterns of normal dermal fibroblasts representing various chronologic ages

• observe the progress of simulated wound healing in the mechanically active environment

• study the response of dermal fibroblasts to the soluble growth factor platelet-derived growth factor (PDGF)

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

1. Studies of Senescent Cell Behavior in Response to PDGF Under Conditions of Varying Stress. Abstract presentation, American Society of Biochemistry and Molecular Biology, Apr. 1993.

2. Dermal Fibroblasts in a Mechanically Active Environment. Paper presented at the American Society for Gravitational and Space Biology, Oct. 1993.

3. Human Dermal Fibroblasts Orient in Response to Applied Stretch. Abstract submitted to Western Regional

Society for Investigative Dermatology Meeting, Feb. 1994.

4. Dermal and Corneal Fibroblasts 'Orienteer' in Response to Applied Mechanical Stretch: A Mechanistic

Approach. Abstract submitted to American Society for Cell Biology, Dec. 1993.

Authorship

1,2 Rosalind A. Grymes and Christine Sawyer, Ames

3 Christine Sawyer and Rosalind A. Grymes

4 Christine Sawyer, Barbara Johnson-Wint, and Rosalind A. Grymes

Planned future work

We have revealed several highly significant effects of the mechanically active environment on our cellular system.

By surveying various regimens of cyclic and static stretch, at different strain levels, we determined that dermal fibroblasts can be studied under all these conditions without indications of deterioration. Cellular behaviors do change,

however, and exhibit adaptation. This adaptation phenomenon reverses the genetic defect observed in one cell strain,

allowing the cultures to respond to the soluble growth factor PDGF only when grown on the flexible membranes.

These findings are unique, and they will be followed up in an intramural grant proposal to the Space Biology Program.

Prepared by Rose Grymes Org. Code SL MS 239-11 Phone (415) 604-3239

114
N/%SA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation The Deuterium Abundance in the Interstellar Medium

Investigator(s) (show affiliation) Michael R. Haas and Alexander G. G. M. Tielens,

Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93 $40,0000

Total expended in FY93: $40,000 (Estimated)

In-house $ 9,000

Contracts (identify) $31,000 NAS2-13605

Grants (identify)

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY94

$40,000

Status of study r--] Completed in FY93 [_ Continued in FY94

If continued in FY94 N---]with funds remaining? [-] with FY94 funds?

If transitioned to other funding, to RTOP (number?.) 352

to Program (name?) to Other (identify)

Purpose of investigation

To determine the deuterium abundance in the interstellar medium by observing several rotational lines of HD and

H 2 in shocked interstellar gas.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

Install Si:As back-illuminated, blocked impurity band (BIBIB) detectors in the Cooled Grating Spectrometer for

flights aboard the Kuiper Airborne Observatory (KAO) in late November 1993. Continue procurement and development of Si:Sb BIBIBs to extend the observations to longer wavelengths. Analyze the resulting flight data and use the

measured line intensities to deduce the deuterium abundance in the Orion molecular cloud. Write up the results for

publication in a scientific journal.

Prepared by Michael R. Haas Org. Code SSA MS 245-6 Phone (415) 604-5511

115
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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Determination of Polar Stratospheric Cloud Onset Over Antarctica Using Cloud Top Temperature

Retrievals from the NOAA Advanced Very High Resolution Radiometer (AVHRR) Satellite Imagery

Investigator(s) (show affiliation) Steve Hipskind, Ames Research Center, Moffett Field, CA 94035-1000

Kathy Pagan, Oswaldo Garcia, and Patricia Foschi, San Francisco State University,

San Francisco, CA 94132

Steve Gaines r Sterling Software t Ames Research Center_ Moffett Field_ CA 94035-1000

Funding Year Initiated FY93 Expected completion date FY94

Total prior to FY93 0 Authorized in FY93

Total expended in FY93: $33,000 (Estimated)

In-house $13,000

Contracts (identify)

Grants (identify) $20,000 SFSU JRI

$33,000

Requested for FY94, if any $401000

Status of study I-] Completed in FY93

If continued in FY94 I--I with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

I_ Continued in FY94

IX] with FY94 funds?

to Other (identify)

Purpose of investigation

Determine whether AVHRR imagery can be used to detect PSCs (polar stratospheric clouds) over Antarctica. If so,

determine date of PSC onset and develop climatology of duration and geographical extent of PSCs.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Results presented in a poster at the annual high speed research program/atmospheric effects of stratospheric

aircraft (HSRP/AESA) meeting in Virginia Beach, Va., June 15,1993.

Planned future work

Conduct intercomparisons with other datasets (surface temperature, upper air, UARS). Develop detection algorithms for optically thin PSCs.

Prepared by Steve Hipskind Org. Code SGA MS 245-5 Phone (415) 604-5076

116
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Real-Time Automated Diagnosis System for the Ames Research Animal Holding Facility

Investigator(s) (show affiliation) David L. Iverson and Stephanie Herrin, Ames Research Center,

Moffett Field, CA 94035-1000

Funding Year Initiated FY92 Expected completion date FY94

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 Authorized in FY93 $40,000

$38,500 (Estimated) Requested for FY94, if any

$34,000

$4,500- RECOM contract, consultant short term hire

Status of study Completed in FY93 r-] Continued in FY94

If continued in FY94 I--] with funds remaining? r-i with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify) Possible funding through Code SP

Purpose of investigation

Improve knowledge engineering and automated monitoring and diagnosis technology by developing general

techniques for constructing automated diagnosis systems using information from reliability analysis models.

Develop a tool for monitoring and diagnosis of the Research Animal Holding Facilities (RAHF) payload.

FY93 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Results of this research were used to build the RAD (Real-Time Automated Diagnosis) system, which was used by

payload controllers and engineers during the SLS-2 Space Shuttle mission to monitor the two RAHFs onboard

Columbia.

The work was published in the Proceedings of the Sixth International Conference on Industrial and Engineering

Applications of Artificial Intelligence. The conference was held in Edinburgh, Scotland, on June 1-4,1993.

Planned future work

Investigate techniques to use reliability models in conjunction with functional models to develop more powerful

monitoring and diagnosis systems.

Prepared by David Iverson Org. Code FIS MS 269-4 Phone (415) 604-3115

117
I I/KSA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Stratospheric Aerosol Particulates: Simulation of Their Morphology, Physical Properties, and

Chemistry

Investigator(s) (show affiliation) Richard L. Jaffe, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93 $40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated)

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY94

$40,000

Status of study [-I Completed in FY93

If continued in FY94 IR] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

IX] Continued in FY94

[-7 with FY94 funds?

to Other (identify)

Purpose of investigation

Simulations of nitric acid-water ice particles and droplets representative of conditions found in polar stratospheric

clouds. In addition, calculations of HC1 interacting with these particles were planned.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

Completion of project as originally proposed.

Prepared by Richard Jaffe Org. Code RTC MS 230-3 Phone (415) 604-6458

118
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation The Use of Molecular Fossils for the Interpretation of Paleoenvironments

Investigator(s) (show affiliation) Linda L. Jahnke, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92 Expected completion date

Total prior to FY93 $35,300 Authorized in FY93

Total expended in FY93: $37,300 (Estimated)

In-house $1,500

Contracts (identify)

Grants (identify) $35,810/NCC2-695

Requested for FY94, if any

FY93

$37,300

Status of study Completed in FY93 I--'1Continued in FY94

If continued in FY94 I-] with funds remaining? r--i with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To understand the synthesis of hopane biomarkers in photosynthetic bacteria and any relationship the presence of

these biomarker molecules might have to the evolution of oxygenic photosynthesis.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Jahnke, L. L.; and Munoz, E.: Characterization of Two Facultatively Anoxygenic Cyanobacteria Isolated from a

Hypersaline Microbial Mat. Abstracts of the 93rd General Meeting of the American Society for Microbiology, 1993,

p. 253.

Planned future work

Publication of peer reviewed journal article on facultative anoxygenic cyanobacteria and application of information gained to analysis of microbial mat material.

Prepared by Linda Jahnke Org. Code SSX MS 239-4 Phone (415) 604-3221

119
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Flight Measured Wall Pressure Fluctuations Beneath Swept Shock/Boundary-Layer Interactions

Investigator(s) (show affiliation) Steven A. Johnson, Dryden Flight Research Facility, Edwards, CA 93523-0273

Funding Year Initiated FY93

Total prior to FY93

Expected completion date

0 Authorized in FY93

Total expended in FY93: $40,000 (Estimated)

In-house $35,000

Contracts (identify) $5,000 C&T Machining

Grants (identify)

Requested for FY94, if any

FY94

$40,000

$40,000

Status of study [--] Completed in FY93

If continued in FY94 [-] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

Continued in FY94

IX] with FY94 funds?

to Other (identify)

Purpose of investigation

The goal of the proposed study is to assess the acoustical loads generated by a swept shock/boundary-layer

interaction in a flight environment (free of wind tunnel turbulence) and to gain a better understanding of the physical

mechanisms involved in their generation. Such an understanding is the first step in any attempt to control or limit

acoustical loading on flight vehicles. Also, more fundamentally, the interaction unsteadiness is critical in formulating

accurate flow models.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

The flight hardware has been designed and constructed.

A prototype signal conditioning card has been designed and constructed.

Pressure transducers have been procured.

Planned future work

A benchtop checkout of the integrated system will be initiated.

A series of four flights will occur.

The data will be analyzed and presented.

Steven A. Johnson XRP Prepared by Org. Code

MS D-2033 Phone (805) 258-3096

120
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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Pyrosensors for the Detection of Chemical Compounds in Planetary Environments

Investigator(s) (show affiliation) Dan Kojiro and Thomas C. Shen, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92 Expected completion date

Total prior to FY93 $40,000 Authorized in FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated) Requested for FY94, if any

$2,000

$38,000 (cooperative agreement NCC2-650)

FY93

$40,000

Status of study Completed in FY93 r--] Continued in FY94

If continued in FY94 r-] with funds remaining? E] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

Developing pyrosensors for Martian soil oxidants analysis.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Shen, Thomas; and Kojiro, Dan: Pyrosensors for Analyzing Oxidants on Martian Soil. ACS Meeting in

Denver, Colo., 1993.

Planned future work

Summit Planetary Instrument Definition Development Proposal to NASA Headquarters.

Prepared by Thomas Shen Org. Code SSS MS 239-12 Phone

(415) 604-5769

i_ • i, _

121
I I/KSA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Practical Evaluation of a New Method to Reduce Helicopter Rotor Hub Loads

Investigator(s) (show affiliation) Sesi Kottapal]i, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

FY93 Expected completion date

0 Authorized in FY93 $11,500

$11,500 (Estimated) Requested for FY94, if any $28r500

University of Maryland at College Park

FY95

Status of study I--i Completed in FY93 Continued in FY94

If continued in FY94 I-7 with funds remaining? IXI with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

Experimental (bench) testing of a new concept, blade root torsional damping, which has been analytically found to

reduce helicopter hub loads.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None.

Planned future work

Initiate design and fabrication of root torsional dampers.

Prepared by Sesi Kottapalli Org. Code FFR MS T-042 Phone (415) 604-3092

122
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Stanford-NASA Ames Cooperative Program in Global Change

Investigator(s) (show affiliation) James G. Lawless and Philip B. Russell, Ames Research Center, Moffett Field, CA 94035-1000

Gary Ernst, Stanford University, Stanford, CA 94305

Funding Year Initiated FY91

Total prior to FY93 $42,500

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

Authorized in FY93

$60,000 (Estimated)

$31,611

Requested for FY94, if any

$28,389 (Joint Research Interchange NCA2-768)

FY94

$4,000

Status of study I--] Completed in FY93 IX] Continued in FY94

If continued in FY94 r-] with funds remaining? [--] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

The purpose of the Stanford-NASA Ames Cooperative Program in Global Change is to bring together the unique

skills and facilities available at Stanford and Ames to answer key questions about the functioning of the Earth's atmosphere and ecosystems, especially as impacted by human activities. Most of the DDF funds have been used to support a

variety of research tasks carried out by students under the joint advisorship of Stanford and Ames scientists. The remainder of the funds helped support a joint seminar series conducted at Stanford and Ames.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Townsend, Alan R.: Influence of Temperature on Soil Carbon Pools. Ph.D. Thesis, Stanford University, 1993.

Imhoff, Marc L.: Remote Estimation of Vegetation Biomass Using AIRSAR. Ph.D. Thesis, Stanford University, 1993.

Planned future work

Several of the student research tasks are still in progress using the funding in Joint Research Interchange (JRI)

NCA2-768. This work will be completed in FY94 and described in the JRI Final Report, which is due in December 1994.

Prepared by Philip B. Russell Org. Code SGG MS 245-5 Phone (415) 604-5404

123
NASA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation The Study of Ozone Depletion Chemistry Using Ab Initio Quantum Mechanical Methods

Investigator(s) (show affiliation). Timothy J. Lee, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

$40,000 Authorized in FY93

$40,000 (Estimated) Requested for FY94, if any

FY93

$40,000

Status of study I--] Completed in FY93

If continued in FY94 r-] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

Continued in FY94

I"-I with FY94 funds?

to Other (identify)

Purpose of investigation

1. To demonstrate the applicability and usefulness of ab initio quantum mechanical methodology to the study of

atmospheric chemistry.

2. To study important molecules and reactions with regards to ozone depletion.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Five journal articles have been completed; the summary of these studies and their significance is given in the DDF

final report.

Planned future work

To continue the study of atmospheric chemistry, includingthe determination of molecular structures, vibrational

and electronic spectra, and other molecular properties, using ab initio quantum mechanical methodology.

Proposals to be submitted to Upper Atmosphere Research Program among others.

Prepared by T.J. Lee Org. Code RTC MS 230-3 Phone (415) 604-5208

124

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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Surface Shear Stress Measurement Using Liquid Crystal Polymers

Investigator(s) (show affiliation) B. G. McLachlan and J. H. Bell, Ames Research Center, Moffett Field, CA 94035-1000

M. L. Brandes and M. Gouterman, University of Washington, Seattle, WA 98195

Funding Year Initiated FY93 Expected completion date

Total prior to FY93 0 Authorized in FY93

$40,000

$40,000

Total (Estimated) expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Requested for FY94, if any

FY94

$40,000

$401000

Status of study I-1 Completed in FY93 [El Continued in FY94

If continued in FY94 r-] with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

Assess the feasibility of liquid crystal polymer film coatings for surface shear stress field measurement in aerodynamic testing.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

Set up an advanced flow apparatus to produce accurate aerodynamic shear stress levels. Evaluate method in tests

conducted in RAC small scale wind tunnel using airfoil surfaces.

Prepared by B.G. McLachlan Org. Code RAC MS 227-2 Phone (415) 604-4142

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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Investigations of Supersonic Combustion Using Unique NASA Ames Facilities

Investigator(s) (show affiliation) Gene P. Menees, Ames Research Center, Moffett Field, CA 94035-1000

Jean-Luc Cambier and Henry G. Adelman, Thermosciences Institute, Ames Research

Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

FY92 Expected completion date

$40,000 Authorized in FY93

$40,000 (Estimated)

$40,000 NCC2-487

Requested for FY94, if any

FY93

$40,000

Status of study [-I Completed in FY93 IX;']Continued in FY94

If continued in FY94 with funds remaining? I--] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To investigate ways to utilize the Direct Connect Arc-Jet Facility (DCAF) for Ames hypersonic propulsion experiments. This involves the design of unique combustion experiments and diagnostic procedures along with the use of

Ames CFD tools for flow prediction and analysis.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

The new CFD code developed in FY 92 has been upgraded by including grid embedding techniques and K-E

turbulence models. This will allow the study of complex injector shapes such as the bifurcated strut. In preparation for

injector studies, a simulation of the flowfield from the nozzle throat to the injectors has been completed. Boundary layer

thickness and heat transfer to the combustor walls have been predicted.

Planned future work

Predictions of pitot pressures at the injector location will be compared to experimental data from the DCAF facility

to validate the flowfield simulations.

Prepared by Gene Menees Org. Code RTA MS 230-2 Phone (415) 604-3465

126
N/KSA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Mixing, Combustion, and Thrust Enhancement by a Pulsed Detonation Wave Augmentor

Investigator(s) (show affiliation) Gene P. Menees, Ames Research Center, Moffett Field, CA 94035-1000

Jean-Luc Cambier and Henry G. Adelman, Thermosciences Institute, Ames Research

Center, Moffett Field, CA 94035-1000

Funding

Total prior to FY93

Year Initiated FY92 Expected completion date

$40,000 Authorized in FY93 $40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated)

$40,000 NCC2-487

Requested for FY94, if any

FY93

Status of study r_ Completed in FY93 r-] Continued in FY94

If continued in FY94 r--] with funds remaining? [---] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

Focus on applications of an innovative concept called the pulsed detonation wave augrnentor (PDWA), which uses

detonation waves to solve problems facing a supersonic combustion engine (i.e., mixing, combustion efficiency, thrust

enhancement, and lightweight packaging).

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Numerical results show that for our configuration (axial mode) achieving strong mixing enhancement with minimal

losses in stagnation pressure is possible. Combustion is also increased by shock heating of the mixing layer. Threedimensional (3-D) effects should lead to even better performance.

Planned future work

Determine effectiveness of concept for external combustion. Perform 3-D simulations.

Prepared by Gene Menees Org. Code RTA MS 230-2 Phone (415) 604-3465

127
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Ablating Surface Heat Transfer Estimation for Flight Application

Investigator(s) (show affiliation) Greg Noffz and Mike Bowman, Dryden Flight Research Facility, Edwards, CA 93523-0273

Funding Year Initiated FY92 Expected completion date

Total prior to FY93 $40,000 Authorized in FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated) Requested for FY94, if any

$35,000

$5,000 (San Jose State University Student)

FY93

$40,000

$40r000

Status of study r-! Completed in FY93 Continued in FY94

If continued in FY94 with funds remaining? [-] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

To develop a capacitive gage capable of measuring the recession of thin layered ablators, thus quantifying the energy

component leaving the surface with ablation products. This type of instrumentation may also be used to measure the

sublimation rate of certain chemicals used in flow visualization experiments.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

1. Continue evaluation of the candidate gages already fabricated.

2. Construct some third generation gages incorporating lessons learned.

3. Obtain calibration data using the actual materials of interest.

4. Complete a system capable of multiplexing and recording data from multiple gages.

5. Conduct a "hot" test using the materials of interest.

Prepared by Greg Noffz Org. Code XRA MS D-2033 Phone (805) 258-2417

128
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Ames Research Center Director's Discretionary Fund, Report

Fiscal Year 1993

Title of Investigation Crew Decision Making in Aerospace Environments: A Taxonomy of Decision Structures

Investigator(s) (show affiliation) Judith Orasanu, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY93 Expected completion date FY94

Total prior to FY93 0 Authorized in FY93 $40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated) Requested for FY94, if any

$40,000 (through San Jose State University Foundation)

$40I ̧000

Status of study r--i Completed in FY93 Continued in FY94

If continued in FY94 r--! with funds remaining? IX;'] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

This project is motivated by two factors: the signficant role of crew judgment and decision errors in aviation

accidents and the absence of guidance from the traditional decision making literature. Its purpose is to develop a

taxonomy of the types of decisions crews face in aerospace environments, and then for each decision type to determine

the cognitive demands, to identify vulnerable points and types of errors, and to describe effective coping strategies.

This knowledge will establish a basis for training standards, crew procedures, and decision aids.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

• Research findings from this project are being used by the following airlines in their crew resource management

training courses: Delta, Northwest, Alaska, TWA, Horizon, Aer Lingus, and SAS. Other industries that are using our

finding, methods, and concepts include hospital emergency shock/trauma centers, nuclear power, offshore oil drilling,

and merchant marine.

• Six presentations at professional meetings and four publications have resulted from this project, including an

invited address at the IATA Conference on Human Factors in Aviation and an invited contribution to a special Human

Factors issue of the ICAO Journal.

Planned future work

• Validate dimensions that define decision structures and difficulty.

• Conduct experiments to test hypotheses about sources of judgement and decision error (especially poor

situation assessment, including time and risk assessment).

• Test validity of effective decision strategies through training studies in collaboration with several airlines.

• Examine shuttle tapes (STS-21) to identify problem solving episodes and assess the structure of the problems

and crew strategies.

Prepared by Judith Orasanu Org. Code FLR MS 262-3 Phone (415) 604-3404

129
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Analysis of Arc-Jet Wind Tunnel Vacuum Ultraviolet (VUV) Experiment

Investigator(s) (show affiliation) Chul Park, Ames Research Center, Moffett Field, CA 94035-1000

Dikran S. Babikian, Thermosciences Institute, Ames Research Center,

Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

FY93

$40,000 (Estimated)

NASA Grant NCC2-42D

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY94

$40,000

$501000

Status of study I--] Completed in FY93 [X--]Continued in FY94

If continued in FY94 [--I with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

- Refine and validate our codes to calculate the radiative heating of our Aeroassisted Space Transfer Vehicle

(ASTV)

- Improve the arc-jet CFD codes to better characterize the flow in arc-jet wind tunnels.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Measurement and Analysis of Nitric Oxide Radiation in an Arc-Jet Flow. AIAA 28th Thermophysics Conference,

Orlando, Fla.

Validation of Multi-Temperature Nozzle Flow Code NOZNT. AIAA 28th Thermophysics Conference, Orlando, Fla.

User's Manual for NOZNT and NOZ1T. Technical note, in review.

Calculated and Measured Spectral Radiation from a Blunt Body Shock Layer in an Arc-Jet Wind Tunnel. 32nd Aerospace

Sciences Meeting and Exhibit, Reno, Nev.

Characterization of Arc-Jet Flows Using Laser-Induced Fluorescence. 32nd Aerospace Sciences Meeting and Exhibit,

Reno, Nev.

Planned future work

Continue the analysis of the available experimental data and the spectroscopic investigation of thermochemical

processes in a blunt body shock layer in an arc-jet.

Papers in Preparation:

Spectroscopic Investigation of Thermochemical Processes in a Blunt Body Shock Layer in an Arc-Jet. 29th

Thermophysics Conference. Prediction and Measurements of VUV Radiation from a Blunt Body Shock layer in an Arc-Jet

Wind Tunnel, for a limited distribution TM.

Prepared by Dikran S. Babikian Org. Code RTA MS 230-2 Phone (415) 604-1144

130
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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation A Miniature, Lightweight Ozone Analyzer for Use on Unmanned Stratospheric Research Aircraft

Investigator(s) (show affiliation) Richard Pearson, Jr., Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92 Expected completion date FY'93

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 Authorized in FY93 0

$40,000 (Estimated)

$40,000

Requested for FY94, if any

Status of study IX] Completed in FY93 r-i Continued in FY94

If continued in FY94 I'-] with funds remaining? I-'1 with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

Our objective was to design and test the critical measuring components for a small, lightweight, low-power ozone

(O3) analyzer for use on unmanned research aircraft such as Perseus. Performance goals were to preserve a measurement

accuracy comparable to the standard ER-2 instrument, while resolving problems of O 3 losses at highest altitudes and

certain critical deficiencies in some other instruments currently in use thought to be due to uncertainties in optical path

length.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

We significantly extended the geometric optic model of the system in this second year. A working (visible or infrared

fight) model of the absorption cell was built and tested as proof of concept, and to verify the accuracy of the complex design

calculations with comparatively inexpensive components. The cell appears to operate precisely as expected, and it was

photographed in laser light showing the beam following the intended path of eight passes through the cell, and exiting

through the window. The final design of the ultraviolet (UV) elements for the cell and interactions between optical and

mechanical parts proved far more difficult than anticipated. As a result, a detailed design is complete, but a prototype UV

instrument has not yet been built.

Planned future work

The proposal developed from this work was turned down under extremely tight funding conditions. We plan to

re-submit as new equipment funds are available in stratospheric chemistry.

Prepared by Richard Pearson, Jr. Org. Code SGG MS 245-5 Phone (415) 604-4388

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IW A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Development of a Polarimeter for Astrophysical Applications in the Midinfrared

Investigator(s) (show affiliation) Yvonne Pendleton, Lynne Deutsch, and Thomas Roellig, Ames Research Center,

Moffett Field, CA 94035-1000

Funding

Total prior to FY93

Year Initiated FY92 Expected completion date

$10,000 Authorized in FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$30,000 (Estimated)

$30,000

Requested for FY94, if any

FY93

$30,000

Status of study I-] Completed in FY93 Continued in FY94

If continued in FY94 r--] with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

Until now, polarimetric observations in the rnidinfrared have been limited to single dectector measurements. In

particular, such observations of the center of our galaxy have shown that there is a wealth of information waiting to be

gathered by a more sensitive and less time consuming method. We proposed to investigate the galactic center region in

just such a manner through the use of two-dimensional polarimetric imaging in the midinfrared.

Our purpose was to investigate the inner few parsec region of the galactic center and other astronomical regions

through high spatial resolution polarimetric imaging. These observations could provide answers to questions about the

number and geometry of the luminosity sources present as well as information regarding grain alignment and the

strength of the galactic magnetic field.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

New astronomical images have been obtained with a new infrared camera (AIR Camera) at NASA's Mt. Lemmon telescope. These images show emission from the young planetary nebula NGC 7027 at two midinfrared wavelengths. Planetary

nebulae are the ejected envelopes of evolved stars. The central star of NGC 7027 is totally obscured by dust in the optical, has

a temperature of 180,000 to 234,000 K, and is located approximately I kpc from our Sun. The midinfrared images reveal a

double lobed structure and a central minimum, which represent a cross-section of a tipped toroid of gas and dust. The dust

ejected by planetary nebulae has been enriched with heavy elements created through the star's nucleosynthesis. The nebula

also contains large carbon molecules, which may be the building blocks of prebiotic material. This material is ultimately

reincorporated into the interstellar medium from which new stars will be formed.

Planned future work

Now that the AIR Camera has been tested out at the telescope, the polarimeter can be used in conjunction with the

•camera. The next step in this project includes taking the camera/polarimeter to various telescopes to observe objects such

as NGC 7027 and the galactic center to further study a variety of astrophysical environments.

Prepared by Yvonne Pendleton Org. Code SSA MS 245-3 Phone (415) 604-4391

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132

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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Three-Dimensional (3-D) Disturbances Generated by Suction Holes for Laminar Flow Control (LFC)

Investigator(s) (show affiliation) Daniel C. Reda and Jonathan H. Watrnuff, Ames Research Center,

Moffett Field, CA 94035-1000

Funding Year Initiated FY93

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

0 Authorized in FY93 $40,000

$40,000 (Estimated)

$4o,ooo

Requested for FY94, if any

FY94

$40r000

Status of study r-] Completed in FY93 _r] Continued in FY94

If continued in FY94 [--] with funds remaining? ['X] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To investigate characteristics of boundary layer disturbances in the vicinity of suction holes and to explore the

conditions under which the disturbances decay or amplify as they propagate downstream.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Interaction Between Instabilities Originating from Suction Holes. Paper to be presented at 46th Annual Meeting of

Division of Fluid Dynamics (APS).

Planned future work

The initial $40,000 funding was used to modify an existing facility, and modification has been completed on schedule. The second year funding was originally estimated at $25,000 but was increased to $40,000 to include purchase of a

new wind tunnel fan motor. An additional $5,000 is requested for a coprocessor that will reduce experiment run time

by a factor of 10 (e.g., 2 days instead of 20 days).

Measurements of the background flow are under way. The test section unsteadiness is 0.08% and the transitional

Re = 2.2 x 106 for an impervious flat plate, which is very good for an open return blower driven tunnel. The mean flow

exhibits the Blasius profiles, although the data have not yet been fully analyzed.

Disturbances generated by an isolated suction hole will be investigated shortly. The suction will be perturbed

harmonically and the data phase,averaged on the basis of the perturbation. Measurements will be made on spatially

dense 3-D grids allowing animations of the T-S-like 3-D waves to be studied on a graphics workstation. Of special

interest is the interaction between disturbances originating from two holes displaced, but aligned in the streamwise

direction. The same techniques will be used to examine possible enhancement, or more significantly, some degree of

cancellation of these waves.

A scaled-up porous surface consisting of 8,966 holes will be used to investigate the interactions between disturbances

on a full suction surface typical of those currently being flight tested for future use in airplane wings and engine nacelles.

Prepared by Jonathan H. Watmuff Org. Code RFR MS 260-1 Phone (415) 604-4150

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133
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation An Ultralow-Temperature Thin-Film Thermometer

Investigator(s) (show affiliation) Pat Roach, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93 0

FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

Authorized in FY93

$35,000 (Estimated) Requested for FY94, if any $381000

$5,000

$30,000 to TransBay Electronics for support service personnel

$38,000

FY94

Status of study [7 Completed in FY93 IX] Continued in FY94

If continued in FY94 I--] with funds remaining? IXrl with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

The purpose of this project is to develop a simple, accurate thermometer that will be useful in the temperature range

of 0.01-0.38 K for use with cryocoolers that are being developed to be operated at 0.10 K and below.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

In FY94 an example of the actual thermometer will be fabricated and tested. The problem of lead attachment will be

resolved and low-temperature tests will be carried out to evaluate the sensitivity and reproducibility of the thermometer.

Problems that develop will be solved.

Prepared by Pat Roach Org. Code SFO MS 244-10 Phone (415) 604-3191

134
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Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Early Warning Blackout Sensor for Pilots and Astronauts

Investigator(s) (show affiliation) S.A. Rositano, Alan Hargens, and Malcolm Cohen,

Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93 0

FY93 Expected completion date

Authorized in FY93

FY94

$39,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$38,000 (Estimated) Requested for FY94, if any $20,000

$18,000

$20,000 (Classic Medical Products, Inc.- Prototype Electrodes/L&M Electronics- Electronic

Circuits)

Status of study I--] Completed in FY93 IX] Continued in FY94

If continued in FY94 I-7 with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

Develop and evaluate a forehead-mounted impedance measuring patch capable of providing a 4- to 7-second

advance warning of impending physiologic limit (blackout) caused by head-to-toe acceleration forces.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Signal processing circuitry has been designed and tested with simplified electrodes. A contract has been awarded to

Classic Medical for production of prototype electrodes. The first integrated test is scheduled for November 93. Preliminary results indicate high probability for detecting the arterial pulse.

Planned future work

Upon successful tests on resting human subjects, tests on the ARC 20-G Centrifuge will be conducted. Refinements in

electronics are expected to provide "smart signal processing" for adaptive artifact suppression.

Prepared by S.A. Rositano Org. Code EES MS 213-2 Phone (415) 604-5480

135
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NASA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation The Infrared Spectra of Microsamples of Cosmic Interest: Diamonds, Silicon Carbide, Interplanetary

Dust Particles, and Organic Residues

Investigator(s) (show affiliation) Scott A. Sandford, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated

Total prior to FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

FY92 Expected completion date

$30,000 Authorized in FY93

$20,000 (Estimated)

$20,000

Requested for FY94, if any

FY93

$20,000

Status of Study IE] Completed in FY93

If continued in FY94 [--! with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

r--i Continued in FY94

I--I with FY94 funds?

to Other (identify)

Purpose of investigation

Obtain the 4000-400 cm -1 infrared spectra of a variety of microsamples for use in astrophysical studies.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

The microscope was used to verify portions of the data intwo papers that are presently in press, one in Meteoritics

and one in The Journal of Physical Chemistry.

Planned future work

The present DDF grant ends in September 1993, but the microscope will continue to be used to supplement other

ongoing studies and will be used heavily if a proposal currently submitted to the Origins of Solar Systems Program is

funded. The microscope will be used primarily for studying interplanetary dust particles and organic residues.

Prepared by Scott Sandford Org. Code SSA MS 245-6 Phone (415) 604-6849

136
NASA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Development of a Direct Measurement Transducer for the Oil Wedge Skin-Friction Technique

Investigator(s) (show affiliation) H. Lee Seegmiller, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92 Expected completion date

Total prior to FY93 0 Authorized in FY93 $23,000

$3,500 (Estimated)

$3,500

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Requested for FY94, if any

FY94

$20,000

Status of study r--] Completed in FY93 [_ Continued in FY94

If continued in FY94 [--] with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To develop a transducer and techniques for measurement of skin friction on model surfaces and aircraft by directly

measuring the thickness of an applied oil film.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

A U.S. Patent application was filed for an aircraft ice detector developed as a spinoff of this investigation.

Planned future work

Complete fabrication of a wind tunnel model and conduct exploratory tests.

Prepared by H. Lee Seegrniller Org. Code RFE MS 229-1 Phone (415) 604-6211

137
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Utility of the Experimental Electro-Optical Camera (SPEC-T) for Assessment of Insect/Drought

Related Forest Mortality

Investigator(s) (show affiliation) Gary A. Shelton and Vincent G. Ambrosia, Ames Research Center,

Moffett Field, CA 94035-1000

James McKean, U.S.D.A. Forest Service, Pleasant Hill, CA 94523

Funding Year Initiated FY93

Total prior to FY93 0

Total expended in FY93: $12,000 + $28,000 (estimated)

In-house

Contracts (identify) NAS-2-13500 + NAS2-13712

Grants (identify)

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY95

$40,000

$401000

Status of study r--] Completed in FY93

If continued in FY94 _-7 with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

IXr] Continued in FY94

r_ with FY94 funds?

to Other (identify)

Purpose of investigation

Evalute the application of a newly developed, high spatial resolution, electro-optical (EO) digital camera system for

use in detecting and mapping insect/drought related forest mortality and other environmental assessments. Test and

evaluate system configuration and utility for inclusion of SPEC-T in NASA supported suite of research and applications aircraft instruments.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

No reports or publications to date. Application assessments of feasibility of an electronic, adjustable focus ring to

facilitate image collection in the electromagnetic visible and the infrared.

Planned future work

Reconstruct EO camera to operational status following unsuccessful 1993 assessment flights. More test flights

planned for early FY94. Funds for 1993 were forward funded for 1994 work. Alignment and image collection timing for

off-nadir viewing are currently in progress.

Prepared by Vincent G. Ambrosia Org. Code SGE MS 242-4 Phone (415) 604-6565

138
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation A Neural Learning Algorithm for Touch Based Control of Mechanical Manipulation

Investigator(s) (show affiliation) Jay Steele, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93 $40.000

Expected completion date

Authorized in FY93

FY93

$40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated)

$40,000

Requested for FY94, if any

Status of study IE] Completed in FY93 I--I Continued in FY94

If continued in FY94 I--] with funds remaining? [-I with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

To develop a new neural learning system capable of directing the movement of autonomous vehicles and manipulators safely around perceived obstacles toward specified goals.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

None

Prepared by Jay Steele Org. Code FIC MS 269-3 Phone (415) 604-0158

139
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Development of a New System for Canopy Architecture Remote Sensing

Investigator(s) (show affiliation) V. C. Vanderbilt, Ames Research Center, Moffett Field, CA 94035-1000

A. W. Sarto and B. J. Van Zeghbroeck, University of Colorado, Boulder, CO 80309

Funding Year Initiated FY93 Expected completion date FY95

Total prior to FY93 0 Authorized in FY93 $40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated) Requested for FY94, if any

$25,000

$15,000 with University of Colorado

$40,000

Status of study r--i Completed in FY93 Continued in FY94

If continued in FY94 1-'1with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

We are developing a new theory and new laser based measurement method for remotely sensing canopy architecture. The theoretical development supports development of a proof-of-concept instrument.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None.

Planned future work '

Engineering interaction model: During the coming year we will develop the engineering interaction model, which

will allow us to predict the properties ofmas well as the information contained inmthe return lidar beam for possible

spatial and temporal modulations of the incident beam. The engineering interaction model will be designed to provide

better insight into the engineering tradeoffs in the design of the lidar sensor.

Proof-of-concept lidar sensor: The information obtained from the theoretical analysis will aid in development of a

ground based, proof-of-concept lidar sensor to be undertaken this coming year.

Prepared by Vern Vanderbilt Org. Code SGE MS 242-4 Phone (415) 604-4254

140
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Optimization of Spatial Auditory Displays for Multiple Communication Channel Intelligibility

Investigator(s) (show affiliation) Elizabeth M. Wenzel and Durand R. Begault, Ames Research Center,

Moffett Field, CA 94035-1000

Funding

Total prior to FY93

Year Initiated FY92

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

$30,374 Authorized in FY93

$37,971 (Estimated) Requested for FY94, if any

$9,000

$22,981 (SJSU Foundation) $5,990 (Sterling Software)

FY94

$37,971

Status of study [-] Completed in FY93

If continued in FY94 _ with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

['7 Continued in FY94

["] with FY94 funds?

to Other (identify)

Purpose of investigation

Improve intelligibility of multiple communication channels for KSC launch personnel.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Results: 6-7 dB improvement with prototype device, Ames Spatial Auditory Display

Patent: ARC 12013-1-CU submitted to U.S. Patent Office, Sept. 1993

Demo Prototype: At Kennedy Space Center Aug. 1993

Award: Patent application considered for Space Act Award 1993

Publications:

1. Begault, D. R.: Call Sign Intelligibility Improvement Using a Spatial Auditory Display. NASA TM-104014, 1993.

2. Begault, D. R.; and Erbe, T. R.: Multichannel Spatial Auditory Display for Speech Communications. In Proceedings

of the 95th Audio Engineering Society Convention, Preprint No. 3707, Audio Engineering Society, New York, N.Y., 1993.

Planned future work

Complete psychoacoustic evaluation for "telephone grade" stimuli and multiple sources.

Durand Be_;ault Org. Code FLM MS 262-2 Phone (415) 604-3920 Prepared by

141
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Musculoskeletal Loading or Unloading with Differential Pressure

Investigator(s) (show affiliation) Robert Whalen and Gregory Breit, Ames Research Center, Moffett Field, CA 94035-1000

Douglas Schwandt, Rehabilitation Research and Development (RR&D) Center,

Palo Alto, CA 94304

Funding

Total prior to FY93

Year Initiated FY92

$40,000

$40,000 (Estimated)

$40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY93

$40,000

Status of study IX] Completed in FY93 I-1 Continued in FY94

If continued in FY94 r-] with funds remaining? I'-'l with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

• to design and fabricate an air pressure chamber and treadmill assembly

• to test the hypothesis that Earth-equivalent skeletal forces are achievable in microgravity

• to simulate hypogravity and hypergravity locomotion on Earth

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

• Hypergravity locomotion to 1.6 G was simulated.

• Differential pressure loading is an effective and feasible method of altering skeletal forces during gait.

• Earth-equivalent lower limb musculoskeleta] forces can be generated in space.

• Results may be used to assist walking by supporting the body during gait rehabihtation.

1. Whalen, R.; Hargens, A.; Schwandt, D.; and Watenpaugh, D.: Musculoskeletal Loading or Unloading with Differentia] Air Pressure. Transactions of the 37th Meeting of the ORS, vol. 16, no. 2, 1991, p. 628.

2. Whalen, R.: Musculoskeletal Adaptation to Mechanical Forces on Earth and in Space. The Physiologist, vol. 36,

suppl. 1, 1993, pp. 127-130.

3. Hargens, A.; Whalen, R.; Watenpaugh, D.; and Schwandt, D.: LBNP to Provide Load Bearing in Space. Aviation

Space Environ. Med., vol. 62, 1991, pp. 934-937.

4. Patent 5,113,339: Exercise Method and Apparatus Utilizing Differential Air Pressure.

Planned future work

• Test the assembly on KC-135 flights

• Veterans' Administration RR&D Center collaboration to develop walking assist device

• Develop flight unit

Prepared by Robert Whalen Org. Code SL MS 239-11 Phone (415) 604-3280

142
N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Aerogel Advanced Material Development

Investigator(s) (show affiliation) Susan White, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY92

Total prior to FY93 $40,000

Expected completion date

Authorized in FY93

FY93

$40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated) Requested for FY94, if any 0

$24,000 (CF Technologies, Inc.)

$16,000 (Department of Energy, Lawrence Livermore National Laboratories)

Status of study I-] Completed in FY93

If continued in FY94 _ with funds remaining?

If transitioned to other funding, to RTOP (number?) 232-01-04

to Program (name?) Base Materials Funding

_-] Continued in FY94

r-i with FY94 funds?

to Other (identify)

Purpose of investigation

The purpose of this investigation was twofold: The first goal was to produce samples of a novel aerogel fiber

composite material, and to investigate its potential as a next-generation thermal production material. The second purpose

of this project was to investigate the use of chemical processing to modify the surface chemistry of an aerogel, to increase

its sintering temperature.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

• Aerogel Materials, Final Report for A24127D, TRW Space and Technology Group, Redondo Beach, Calif.

• Hnabesh, L.: Enhanced Thermal Capacity Aerogels, Summary Report for Contract No. A-26310D/L-1342, Lawrence

Livermore National Laboratory, Livermore, Calif.

• White, Susan; Lee, Siu-Chun; and Grzesik, Jan: Advanced Particulate Fibrous Composite for Thermal Control of

Re-entry Vehicles. AIAA Paper 93-2824, AIAA 28th Thermophysics Conference, Orlando, Fla. Submitted to J. Quant.

Spectros. Radiat. Trans., 1993.

• Lee, Siu-Chun; White, Susan; and Grzesik, Jan: Effect of Particle Size in Composite Materials on Radiative Properties.

AIAA Paper 93-2729, AIAA 28th Thermophysics Conference, Orlando, Fla. Submitted to AIAA J. Thermophysics, 1993.

• Submitted to International Symposium on Aerogels (ISA4)

• Patent applied for:

1. Aerogel-loaded Tile Composite Material

2. Fiber-reinforced Silica Aerogels

Planned future work

Complete current work on developing optimized composites.

Test material properties (mechanical properties, thermal conductivity).

Test materials in intended application.

Write and publish final results.

Prepared by Susan White Org. Code RTlVl MS 234-1 Phone (415) 604-6617

143
i• /

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Effects of Low Energy Impact of Atomic Oxygen and Nitrogen on Advanced Materials

Investigator(s) (show affiliation) Susan White, Joan Pallix, and Les Barnes, Ames Research Center,

Moffett Field, CA 94035-1000

Funding Year Initiated FY93 Expected completion date FY94

Total prior to FY93

Total expended in FY93: $40,000

In-house $20,000

Contracts (identify) $20,000

Grants (identify)

(Estimated)

Authorized in FY93

Requested for FY94, if any

$40,000

,i ̧ _.:

Status of study I--] Completed in FY93 Continued in FY94

If continued in FY94 [--I with funds remaining? IXrl with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

To understand the fundamental physical processes responsible for atom recombination and subsequent heating of

thermal protection materials.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Final reports for work completed in FY93 include:

Copeland, R.; and Pal]ix, J.: Oxygen Atom Scattering and Recombination Experiments.

Amon, L., and Barnes, L.: Methods for Studying the Alpha-Quartz Surface.

To be published when the FY94 work is complete.

Planned future work

Complete spectroscopic measurements of recombination product formation on reaction controlled glass (RCG) and

silica surfaces.

Use infrared (IR) spectroscopy to measure surface binding energies.

Use computational methods studied in FY93 to model gas-surface interactions.

Prepared by Joan Pallix Org. Code RTM MS 234-1 Phone (415) 604-0332

144
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N/K6A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Application of Digital Signal Processing (DSP) to Near Real-Time Compensation of Attenuated

Acoustical and Unsteady Pressure Measurements

Investigator(s) (show affiliation) Stephen A. Whitmore, Dryden Flight Research Facility, Edwards, CA 93523-0273

Funding Year Initiated FY93 Expected completion date FY95

Total prior to FY93 Authorized in FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000 (Estimated) Requested for FY94, if any

$30,500

$9,500 (San Jose State University Students)

$40,000

$40,000

Status of study [--] Completed in FY93 Continued in FY94

If continued in FY94 [-'7 with funds remaining? P_ with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To develop methods for numerical compensation of pressure measurement distortion induced by pneumatic

tubing, which cannot be mitigated in the instrumentation design. The compensation will be performed in real time

using digital signal processing (DSP) technology.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

None

Planned future work

Miniaturization and packaging of the developed hardware and algorithms for use in wind tunnel and flight tests.

Prepared by Stephen A. Whitmore Org. Code XRA MS D-2033 Phone (805) 258-2002

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145
N/ SA

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Technology Development for Selective Recovery of Urea from Urine and Its Subsequent Decomposition to Ammonia with Application in the Controlled Ecological Life Support Systems (CELSS)

Investigator(s) (show affiliation) Richard Wisniewski, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY93 Expected completion date FY94

Total prior to FY93 0 Authorized in FY93 $40,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$40,000

$4o,ooo

(Estimated) Requested for FY94, if any $401000

Status of study r-] Completed in FY93 [El Continued in FY94

If continued in FY94 [-'1 with funds remaining? IX] with FY94 funds?

If transitioned to other funding, to RTOP (number?)

to Program (name?) to Other (identify)

Purpose of investigation

The objective of this study is to develop a technology for separation of urea and salts from urine. Urea will be a major

component of the nitrogen balance loop and will be used as fertilizer for plants in CELSS.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Results not yet published but have been reported in monthly reports.

Planned future work

Design longer batch electrophoretic chamber and continue experiments on diffusion. Begin urea separation experiments with free-flow and capillary electrophoresis systems. Develop method of decomposition of urea into ammonia.

Prepared by Richard Wisniewski Org. Code SAR MS 239-11 Phone (415) 604-1024

146
Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation MIR Study of Disks Around Young Stellar Objects

Investigator(s) (show affiliation) Fred Witteborn, Ames Research Center, Moffett Field, CA 94035-1000

Harold M. Butner, DTM-Carnegie Institute, Washington, DC 20015

Funding Year Initiated FY92 Expected completion date

Total prior to FY93 $25,000 Authorized in FY93

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$28,000 (Estimated) Requested for FY94, if any

$28,000 (Center for Star Formation)

FY93

$28,000

Status of study I--] Completed in FY93 I_ Continued in FY94

If continued in FY94 I'-1 with funds remaining? I'-I with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

To develop more realistic models for the physical conditions in disk models, and to extend high resolution midinfrared (MIR) observations to a uniform sample of stars that are thought to have disks surrounding them. By combining the disk models and the midinfrared observations with radiative transport models of the circumstellar envelopes

and existing far-infrared data, we can develop a more complete source model for young stars.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

A number of papers have resulted from the work thus far, and more are anticipated over the next year or so. As a

result the initial project has greatly expanded to include a large range of young stellar objects.

Planned future work

Over the next two to three years, we plan to obtain a large sample of midinfrared spectra from young stars. We

have also begun a program to obtain spatial resolved midinfrared data on the brighter sources. We are in the process

of building up a large set of data on young stellar objects for which we have detailed source models of the disks and

the surrounding envelope. The project has received support from the NASA Origins of the Solar System program.

Prepared by Harold M. Butner Org. Code SSA MS 245-6 Phone (415) 604-5520

147
• i_i _

N/ A

Ames Research Center Director's Discretionary Fund Report

Fiscal Year 1993

Title of Investigation Predicting Lyme Disease Risk: A Remote Sensing Model Based on Landscape Epidemiology

Investigator(s) (show affiliation) Byron L. Wood, James G. Lawless, Louisa R. Beck, and Sheri W. Dister,

Ames Research Center, Moffett Field, CA 94035-1000

Durland Fish, New York Medical College, Valhalla, NY 10595

Funding Year Initiated FY92

Total prior to FY93 $36,000

Total expended in FY93:

In-house

Contracts (identify)

Grants (identify)

$36,000 (Estimated)

$36,000

Expected completion date

Authorized in FY93

Requested for FY94, if any

FY93

$36,000

Status of study IX] Completed in FY93 r-i Continued in FY94

If continued in FY94 r-] with funds remaining? r--] with FY94 funds?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) to Other (identify)

Purpose of investigation

The goal of this research was to develop a remote sensing-based spatial model (geographic information system,

GIS) to describe key landscape features and predict areas where humans are at greatest risk of acquiring Lyme disease.

This model was used to generate a Lyme disease risk map of the Westchester County, New York, study area.

FY93 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Development of a landscape level model to predict Lyme disease risk.

Dister, Sheri W.; Beck, Louisa R.; Wood, Byron L.; Falco, R.; and Fish, Durland: The Use of GIS and Remote Sensing

Techniques in a Landscape Approach to the Study of Lyme Disease Transmission Risk. Proceedings, Seventh Annual

Symposium on Geographic Information Systems in Forestry, Environmental and Natural Resource Management,

Vancouver, B.C., Feb. 15-18, 1993.

Four conference presentations of the results of the DDF research.

Planned future work

Completion of all tasks included in the initial DDF proposal.

Submission of collaborative NASA, National Insitutes of Health, and Centers for Disease Control research proposal.

Submission of paper summarizing the final results of the DDF research.

Prepared by Byron L. Wood Org. Code SGE MS 242-4 Phone (415) 604-4187

148

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REPORT DOCUMENTATION PAGE I Form oMBApproved No o7o4-o188

Public reportingburdenfor thiscollection of informationis estimated to average 1 hourper response,includingthe time for reviewing instructions,searchingexisting data sources,

gatheringand maintaining the data needed, and completing and reviewingthe collectionof information. Send comments regardingthis burdenestimateor any other aspect of this

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1. AGENCY USE ONLY (Leave blank) | 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

! August 1994 Technical Memorandum, Fiscal Year 1993

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Director's Discretionary Fund Report for FY 1993

6. AUTHOR(S)

Ames-Moffett and Ames-Dryden Investigators

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

Ames Research Center

Moffett Field, CA 94035-1000

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

307-51-50

8. PERFORMING ORGANIZATION

REPORT NUMBER

A-94036

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

NASA TM-108813

11. SUPPLEMENTARY NOTES

Point of Contact: John T. Howe, Ames Research Center, MS 200-16, Moffett Field, CA 94035-1000

(415) 604-5500

'_2a. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified-Unlimited

Subject Category- 99

12b. DISTRIBUTION CODE

1"_". ABSTRACT (Maximum 200 words)

This technical memorandum contains brief technical papers describing research and technology

development programs sponsored by the Ames Research Center Director's Discretionary Fund during

fiscal year 1993 (October 1992 through September 1993). An appendix provides administrative information for each of the sponsored research programs.

14. SUBJECT TERMS

Director's Discretionary Fund, Space science, Life science, Aeronautics,

Space and terrestrial applications

17. SECURtTYOFunclassifiedREPoRTCLASSiF_I 8. SECURITYOFunclassifiedTHIS PAGECLASSIFICATIO'_""_-- 19. SECURITYoF ABSTRAcTCLASSIFICATIO"'"_'_

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20. LIMITATION OF ABSTRACT

Standard Form 298 (Rev. 2-89)

Proscribed by ANSI Std. Z39-18