NASA Technical Memorandum 108848

y;s5-9

,_- II0

Director's Discretionary Fund

Report for Fiscal Year 1994

Ames Research Center

February 1995

(NASA-TM-IO884B) OIRECTOR*S

DISCRETIONARY FUND REPORT FOR

FISCAL YEAR 1994 Report, Oct. 1993

- Sep. 1994 (NASA. Ames Research

Center) 110 p

G3/99

N95-22920

Unclas

0042558

National Aeronautics and

Space Administration

NASATechnicalMemorandum108848

Director's Discretionary Fund

Report for Fiscal Year 1994

Ames Research Center, Moffett Field, California

February 1995

National Aeronautics and

Space Administration

Ames Research Center

Moffett Field, CA 94035-1000

CONTENTS

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

Section 1: Final Reports

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

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

David F. Blake

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

Hector L. D'Antoni

Schmidt-Cassegrain Long-Range Laser Velocirneter ....................................................................................

Stephen E. Dunagan

Detection of Life Forms: Extant, Dormant, or Extinct ...................................................................................

Rosalind A. Grymes, Christine Sawyer, and Jay Shafto

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, Oswaldo Garcia, Patricia Foschi, and Steve Gaines

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

Greg Noffz and Mike Bowrtian

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

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

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

Daniel C. Reda and Jonathan H. Watmuff

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

H. Lee Seegmiller

Effects of Atomic Oxygen and Nitrogen on Advanced Thermal Protection 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

Page

vii

10

15

18

23

26

28

30

31

34

111 _v,.., / ; f.. r

,t'
Section 2: Ongoing Reports

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

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

David F. Blake and Jack Farmer

Isotopic Analysis of Meteoritic Organosulfur and Organophosphorous Compounds ...........................

Sherwood Chang

Robust Nonlinear Control and Guidance System Design Methods ...........................................................

Victor H. L. Cheng

Study of Efficiency Gain and Emission Reduction in a Pulse Combustor Design for Jet Engines ........

G. S. Deiwert, J-L. Carnbier, and Henry G. Adelman

Biotechnological Applications of Reuseable Surface Insulation .................................................................

Howard E. Goldstein and Daniel B. Leiser

A Long-Duration Test Flight of a Super-Pressure Balloon as a Platform for Mars Exploration ............

Robert M. Haberle, G. Scott Hubbard, Lawrence G. Lemke, and Geoffrey A. Briggs

Intervertebral Disc and Back Pain Studies Using Spinal Traction and Compression during

Magnetic Resonance Imaging ...........................................................................................................................

Alan R. Hargens, Gita Murthy, Donald E. Watenpaugh, Jorma Styf,

Karen J. Hutchinson, and Douglas F. Schwandt

Turbulent Boundary Layer Measurements on Transport Wing Wind Tunnel Models ...........................

Dennis A. Johnson and Jeffrey D. Brown

Flight Measured Wall Pressure Fluctuations Beneath Swept Shock/Boundary Layer

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

Steven A. Johnson

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

Sesi Kottapalli

Computational Fluid Dynamics (CFD) Simulation of Left Ventricular Assist Device (LVAD) .............

Dochan Kwak and Cetin Kiris

A Study of Atmospheric Sampling by Supersonic Aircraft .........................................................................

Stephen R. Langhoff and Henry G. Adelman

Formation of Organic Matter from Carbon Dissolved in Minerals ............................................................

Narcinda Lerner and Friedemann Freund

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

B. G. McLachlan and ]. H. Bell

Impacts of Automated Differentiation on Numerical Design Optimization ............................................

Hirokazu Miura and llan Kroo

The Opacity of Water Vapor .............................................................................................................................

Harry Partridge and David Schwenke

39

41

42

43

45

46

47

49

5O

52

54

55

56

58

59

60

iv
An Ultralow-Temperature Thin-Film Thermometer .................................................................................... 61

Pat R. Roach

Deep Near-Infrared Cosmological Surveys ....................................................................................................

Thomas L. Roellig, Edwin F. Erickson, and Jacqueline A. Davidson

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

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

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

Technology Utilization of Adaptive Structures in Active Electronic Equipment Isolation ....................

David F. Voracek

Does the Collapse of Diatom Blooms Trigger Coccolithophore Blooms? ..................................................

Robert Wrigley and Lynn Rothschild

Appendix A-l: Final Reports ..................................................................................................................................

Appendix A-2: Ongoing Reports ............................................................................................................................

63

64

65

67

68

69

83

v

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 12 final projects and 21 ongoing projects in Fiscal Year 1994.

The contents are listed alphabetically according to the last name of the primary investigator in two sections (final

and ongoing reports). Following the narrative reports, t_vo appendixes (for final and ongoing reports) contain

brief descriptions with the financial distribution and status of each of the projects.

Any questions can be addressed to an investigator directly.

vii

PAGE _ ( ,,INTENIIONALLYBLANK

SECTION 1

FINAL REPORTS

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

NASA's interest in this area of research is twofold:

First, NASA is tasked under the Mission to Planet

Earth with investigating the general impact of humankind's activities on Earth's ecosystems; second, NASA

is conducting studies to evaluate the atmospheric

effects of stratospheric aircraft.

The discovery of ozone depletion in the stratosphere (Farman et al., 1985) and the elucidation of the

mechanism of its destruction have ranked as two of

the most dramatic scientific discoveries of recent times.

The chlorofluorocarbon (CFC)-induced depletion of

ozone in the polar stratosphere is known to involve

chemical reactions that occur on the surfaces of polar

stratospheric cloud (PSC) particles (Solomon et al.,

1986; Tolbert et al., 1987; Molina et al., 1987). However,

the identity of the phases present in PSCs has been a

matter of some uncertainty since natural PSC particles

have never been analyzed. PSC particles are thought to

be composed of nitric acid hydrates since these crystalline compounds are stable under the pressure, temperature, and composition (P,T,X) conditions

prevalent where the clouds form. Laboratory studies

of these compounds have been conducted to determine reaction rates, sticking coefficients, etc. on model

PSC surfaces in order to constrain these parameters in

atmospheric models. However, in many cases the

structure of the solid phases used as model PSC substrates is not known (i.e., crystalline or amorphous,

single or multiphase, single crystal or polycrystalline).

Furthermore, the substrates themselves typically consist of fiat layers of ice condensed inside tubes or flow

reactors, physically quite unlike the submicron PSC

particles they are intended to model.

The objective of this investigation is to directly

identify the phases that exist within PSC ice particles

grown under realistic conditions in the laboratory. We

do this by growing PSC ice analogs under the same

conditions as exist in the polar stratosphere and studying their structure using diffraction techniques. We

hope that the results will help to clarify important

issues such as the cause of the expansion of the

Antarctic ozone hole, the likelihood of an Arctic ozone

hole, and the possibility that observed ozone

depletions above the midlatitudes will persist or

become widespread. Once the phases present in PSCs

are identified and their conditions of formation are

known, we will be better able to assess the potential

risks of various planned anthropogenic activities in the

stratosphere.

Progress and results

A critical component of this investigation is the ability

to deposit known ratios of gases such as water vapor

and nitric acid vapor onto cold substrates suitable for

viewing in an electron microscope. A gas mixing and

gas inlet rack was designed, built, and interfaced to a

vacuum station for this purpose. A sample insertion

mechanism from an electron microscope was modified

to fit into the chamber of the vacuum station. A cryotransfer sample holder from an electron microscope

can be inserted into the chamber and used as a cold

substrate for depositing ices. The frozen sample can

then be removed from the deposition apparatus in its

cryoholder, transferred to an electron microscope, and

viewed in its pristine state.

Nitric acid hydrates are thought to be principal

components of PSCs. The experiments we are

presently conducting have as their goal the characterization of all the hydrates that exist within the nitric

acid-water system. Crystal structures have been

determined for the monohydrate (Luzzati, 1951) and

trihydrate (Taesler et al., 1975), but nothing is known

of the structure of the dihydrate or of the higher

hydrates reported by others (Ritzhaupt and Devlin,

1991). Furthermore, the structural determinations of

Luzzati and Taesler were performed on liquids

crystallized inside capillary tubes under more or less

equilibrium conditions. Natural PSC ices or PSC analog ices grown in the laboratory by vapor deposition

may not achieve equilibrium during the time course of

an experiment and may indeed be metastable phases

quite different from the equilibrium products for

which crystal structures have been determined.

In our experiments, vapor generated from nitric

acid-water mixtures of specific compositions (Hanson

and Mauersberger, 1988) is leaked into a chamber

under high vacuum and deposited onto a thin carbon

film as an amorphous ice at -170 ° C. The deposit is

then warmed to -75 ° C or some other preselected temperature, at which time the material crystallizes. The

stage is then rapidly cooled to -175 ° C so that no further changes occur in the ice, and the sample is
transferred in the frozen state to a specially equipped

electron microscope. Our first experiments were to

characterize the trihydrate for which at least two structures are suggested (Tolbert and Middlebrook, 1990),

the o_ and [_ forms. A 3:1 water:nitric acid vapor mixture was leaked into the chamber and deposited onto

the cold substrate. At low temperatures, the mixture

was deposited as an amorphous solid and, when

warmed above about 175 ° C, formed a crystalline

material (fig. 1). This crystalline material, which has

peaks at 8.64, 6.32, 5.46, 5.41, 4.61, 4.32, 4.13, 3.72, 3.56,

and 3.38/_, could not be identified as the trihydrate,

and we assume that a different stoichiometry of

water:nitric acid was produced by differing sticking

coefficients of the two gas species on the cold substrate. These preliminary results were presented in

Blake (1994). We believe that the material produced in

these experiments is in fact the dihydrate of nitric acid,

for which a crystal structure has not yet been

determined.

Figure 1. Diffraction pattern o./:3:1 (nominal) water: nitric

acid gas mixture, deposited at 115 K and annealed at 173 K

for 15 minutes under mid-lO -5 Torr range pressure. The

sample was then cooled to 115 K and transferred to the

electron microscope in the frozen state. The measured

diffractions do not correspond to either the trihydrate or the

mono hydrate. It is possible tlmt the dihydrate of nitric acid

was formed, but this phase has not yet been characterized by

diffraction.

Significance of the results

The experiments described above represent our results

to date. Although the technique appears to work, one

needs to account for the sticking coefficients of the various gases at the temperatures of vapor deposition.

There are additional problems associated with constrictions in the gas delivery system, which would create kinetic obstacles to gas equilibration, and the slow

rate at which the icy solid changes phase at the low

temperatures of the experiments.

In addition to demonstrating the ability of the

deposition apparatus to perform experiments of this

type, we have for the first time created a diffraction

pattern characteristic of the structure of (we believe)

the dihydrate of nitric acid. The results from this work

are included in a proposal to the Innovative Research

Program for formal funding. In future work, we will

interface an infrared spectrometer to the deposition

chamber so that the composition of the gas and the

solid ice formed on the substrate can be determined. In

this way, we will be able to compare our structural

results directly to laboratory infrared spectra reported

by others. In addition, we will be able to control for

factors such as sticking coefficients and the like by

directly analyzing both the gas and the as-deposited

icy solid.

Publications resulting from study

Blake, D. F.: Laboratory Investigation of the Growth

and Crystal Structure of Nitric Acid Hydrates by

Transmission Electron Microscopy (TEM).

Atmospheric Effects of Stratospheric Aircraft

(AESA) meeting, Virginia Beach, Va., June 1994.

References

Farman, J. C.; Gardiner, B. G.; et al.: Large Losses of

Total Ozone in Antarctica Reveal Seasonal

C1Ox/NOx interaction. Nature, vol. 315, 1985,

pp. 207-210.

Hanson, D. R.; and Mauersberger, K.: Vapor Pressures

of HNO3/H20 Solutions at Low Temperatures. J.

Phys. Chem., vol. 92, 1988, pp. 6167-6170.

Luzzati, V.: Structure Cristalline de L'acide Nitrique a

une Molecule D'eau. Acta Crystollogr., vol. 4,

1951, pp. 239-244.

Molina, M. J.; Tso, T.; M0iina, L. T.; and Wang, F. C. Y.:

Antarctic Stratospheric Chemistry of Chlorine

Nit_ate, Hydrogen Chloride, and Ice: Release of

Active Chlorine. Science, vol. 238, 1987,

pp. 1253-1257.

Ritzhaupt, G.; and Devlin, J. P.: Infrared Spectra of

Nitric and Hydrochloric Acid Hydrate Thin Films.

J. Phys. Chem., vol. 95, 1991, pp. 90-95.
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.

Taesler, I.; Delaplane, R. G.; et al.: Hydrogen Bond

Studies. XCIV. "Diaquaoxonium Ion in Nitric Acid

Trihydrate." Acta Crystollogr., vol. B31, 1975,

pp. 1489-1492.

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.

Tolbert, M. A.; and Middlebrook, A. M.: Fourier

Transform Infrared Studies of Model Polar Stratospheric Cloud Surfaces: Growth and Evaporation

of Ice and Nitric Acid/Ice. J. Geophys. Res.,

vol. 95(D13), 1990, pp. 22 and 431.

Keywords

Polar stratospheric clouds, Ozone, Nitric acid hydrate

3
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

To develop a method to link remote sensing data to

modem pollen data, and to generate predictive tools

and use them to hindcast paleoenvironmental data

that can provide larger time windows to current

models of global change.

Progress and results

A method was developed for calibrating modem

pollen data in terms of remote sensing data. The

proposed method is useful to predict radiometric

data in regions (such as southern Patagonia) where

the paucity of modern climate data is a major obstacle for research in paleoclimatology and paleoecology. The new reconstructions of past environments

combine the rich information produced by pollen

analysis with a simulation of remote sensing data of

vegetation. Such simulation can be fed to models of

global change that use remote sensing data of vegetation and thus bring their time frame from the current few decades up to several thousands of years. A

paper describing this methodology was published in

1993 (D'Antoni and Spanner, 1993). A first application of the method to hindcast simple ratio vegetation index (SRVI) from fossil pollen data of

postglacial sedimentary profiles of southern

Argentina was discussed in San Diego at the 26th

meeting of the American Association of Stratigraphic Palynologists (D'Antoni, 1992). An application of the method to hindcast the normalized

differences vegetation index (NDVI) was discussed

at the Third Symposium on South America, Landscape Development, Paleoecology and Climate History of the Arid Diagonal of South America in the

Recent Quaternary, held at Bamberg University,

Germany, in July 1994 (D'Antoni, 1994a). This contribution has been accepted for publication in a special issue of the Bamberger Geographische Schriften

(D'Antoni, 1994b).

As an extension of my current research I made a

detailed study of vegetation and climate maps,

which produced the data necessary to conduct a

paleoclimatic study of central Mexico. Whereas

geologists held that about 2,500 years before the present (BP) there was a cold phase with glaciers

extending over lower elevations, traditional palynological interpretation suggested a temperature rise

and the establishment of temperate forests at

3,000 meters above sea level in central Mexico. By

calibrating predictive equations I concluded that

pollen also indicated a sharp temperature drop at

2,500 BP (D'Antoni, 1993).

Remote sensing data from the National Oceanic

and Atmospheric Administration (NOAA-9)

advanced very high resolution radiometer

(AVHRR) from channels I (0.580-0.680 _m) and 2

(0.275-1.100 _tm) were used to calculate albedo

values at 74 stations across southern Patagonia and

Tierra del Fuego (Argentina). These values were

used to calculate vegetation indices (SRVI, NDVI)

for each station. Remote sensing data were acquired

on February 18, 1987, a few weeks after field work in

Patagonia produced surface soil samples from all

74 stations. Soil samples were analyzed for their

pollen content. Thus, each station had a remote sensing value (I used reflectance data from both channels I and 2 or vegetation indices) and a pollen

spectrum (the pollen content of the sample in percentage of a total pollen sum). At this point, multiple

linear regression (MLR) was used to calibrate pollen

spectra in terms of remote sensing of vegetation.

Since the relationships between pollen spectra and

remote sensing data are not necessarily linear, linearization was performed in order to obtain better

fitting while remaining within the framework of

MLR, a methodology that is easy to use and very

familiar to pollen analysts. Once a good model was

available, it was loaded with fossil pollen data, and

"paleo" remote sensing data were produced. A SRVI

or NDVI value was thus calculated for each fossil

sample. Seventy-four stations were studied in southern Patagonia and Tierra del Fuego for modem

pollen content of the soil surface and 40 stations

were similarly studied in central Oregon. Whereas

human impact on the landscape was easy to identify

in Argentine pollen spectra, the Oregon transect

showed anomalies in modem pollen spectra that

probably reflect the large impact of human action on

natural vegetation. Therefore, I considered it safer to

develop and test the new method on the South

American database.

To illustrate the results of the paleoecological

research I will discuss profile Meseta Latorre I

(southern Patagonia). Meseta Latorre I was originally investigated by Frank Schabitz (1991). For
calibratingthepredictive models of Patagonia I used

the PROPAL database developed under my guidance and remote sensing data from the AVHRR

mounted on the NOAA-9 satellite.

A relative pollen diagram of profile Meseta

Latorre I is used as a case in point. The site Meseta

Latorre is a peat bog located at 51031 ' S, 72o03 ' W,

and 1,000 m above sea level, near the present upper

timberline. Sch/ibitz (1991) considers that fluctua- "

tions of the Nothofagus curve (fig. 1) are related to

temperature fluctuations. Zonation was performed

with the CONISS algorithm for cluster analysis. Two

zones were identified, each with several subzones.

Zone 1

Subzone 1. Four lower levels. Dominance of Cyperaceae, with minor proportions of Gramineae,

Empetrum and Nothofagus. Mean hindcasted NDVI,

mh-NDVI = 0.061 + 0.067.

Subzone 2. Next eight levels. Dominance of

Cyperaceae is slowly taken over by Gramineae and

Nothofagus. The upper layer of this subzone is the

end of Zone 1. mh-NDVI = 0.162 + 0.035.

Zone 2

Subzone 1. Next four levels. Nothofagus becomes

dominant accompanied by Gramineae, while

Cyperaceae show reduced values.

mh-NDVI = 0.213 + 0.027.

Subzone 2. Next six levels. Nothofagus is at

its highest values in the profile. Cyperaceae are

at their lowest. Gramineae are around 20 percent.

mh-NDVI = 0.250 + 0.017.

Subzone 3. Next six levels. Nothofagus is

dominant accompanied by Gramineae. There is a

significant increase of Cyperaceae.

mh-NDVI = 0.220 + 0.014.

Subzone 4. Next three levels. Nothofagus is dominant and both Gramineae and Cyperaceae show

reduced proportions, mh-NDVI = 0.250 + 0.015.

Subzone 5. The upper three levels. Small retreat

of Nothofagus and Cyperaceae and a strong advance

of Gramineae. mh-NDVI = 0.239 + 0.012.

The postglacial history of vegetation at this latitude is significant because the period between

9,055 + 140 years BP and about 4,000 BP has open

vegetation of Cyperaceae with geophytic life form,

well adapted to cold winters, thus reflecting an

Andean location above the upper timberline. After

that time, the expansion of Nothofagus forests shows

a more benign climate. The mh-NDVIs show that

soil coverage is moderate throughout the whole

profile. However, the mh-NDVI crosses the thresh

old of 0.200 about 5,100 years BP, a fact that we

interpreted as an indication that the forest occupied

Meseta Latorre and has remained there to the

present.

Hindcasted NDVIs provide a solid description

of vegetation when combined with traditional fossil

pollen data. The proposed methodology will produce a more realistic reconstruction of past environments when 'snapshots' of remote sensing data

of vegetation are replaced by time-series of data.

These reconstructions made in terms of vegetation

indices (NDVI) are used to describe modem vegetation from remote sensing data. Thus, past and present studies of vegetation can be related using the

same codes. Models of global change can use simulations based on studies of paleovegetation to

enlarge their currently short time frame.

This project produced a large amount of original

data and an extensive database was developed by

reviewing the early works of H. P. Hansen (Hansen,

1946) for Oregon and Washington. The modem

pollen database for central Oregon is close to completion. I studied all the profiles published by

Hansen and generated new statistics and diagrams

that allow interpretation using modem techniques.

These changes allow a direct comparison with profiles dated by C. J. Heusser for Oregon and

Washington. Also in progress is our interpretation

on our studies of racemization of aspartic acid in

peat profiles of southern Patagonia and Tierra del

Fuego.

My interest for South American ecology as well

as interaction with several colleagues at the Ames

Research Center led me to initiate a research program on the effects of stratospheric ozone depletion

and increased levels of ultraviolet (UV) radiation on

Subantarctic forests and western Patagonian steppe.

I suggested performing field work in regions where

increases in UV radiation were detected or

suspected, by subtracting part of the current UV

radiation to simulate conditions under 0 percent

ozone depletibn. A project was written by a group of

collaborators, reviewed by 20 highly qualified

American and foreign UV-B specialists, and published (D'Antoni et al., 1994).

Publications resulting from study

D'Antoni, H. L.; and Spanner, M. A.: Remote

Sensing and Modem Pollen Dispersal in Southern

Patagonia and Tierra del Fuego (Argentina):

Models for Palaeoecology. Grana, vol. 32, 1993,

pp. 29-39.
O

O

t--

O

cm

0

C_4

. .?.,_

"N

c

0

Z

0

L

N N N N N N

%

f _ A

f _ A A __

F

F

F

1

4_d_fl

i u

N

_F

-- _,aF

F

F

,, F

I

o

t_

0

E
D'Antoni, H. L.: Pollen Analysis in Southern

Patagonia: From Space to Time. Paper presented

at the 26th Meeting of the American Association

of Stratigraphic Palynologists, San Diego, Calif.,

1992.

D'Antoni, H. L.; Armstrong, R.; Coughlan, J.; Skiles,

J.; and Daleo, G. R.: Remote Sensing and

Palaeoecology in Southern Patagonia.

Proceedings of the 3rd Symposium on South

America, Landscape Development, Paleoecology

and Climate History of the Arid Diagonal of

Southern America in the Recent Quaternary,

Bamberg, Germany, July 1994.

D'Antoni, H. L.: Paleotemperatures of La Malinche:

A Palynological Hypothesis. Grana, vol. 32, 1993,

pp. 354-358.

D'Antoni, H. L.; Armstrong, R.; Coughlan, J.; Skiles,

J.; and Daleo, G. R.: Effects of Stratospheric Ozone

Depletion and Increased Levels of Ultraviolet

Radiation on Subantarctic Forests and Western

Patagonian Steppe: A Research Project in

Stratospheric Ozone Depletion/UV-B Radiation

in the Biosphere, R. H. Biggs and M. E. B. Joyner,

eds., NATO ASI Series I, vol. 18, Springer-Verlag,

Berlin, 1994, pp. 81-96.

References

D'Antoni, H. L.: Pollen Analysis in Southern

Patagonia: From Space to Time. Paper presented

at the 26th Meeting of the American Association

of Stratigraphic Palynologists, San Diego, Calif.,

1992. (Paper in preparation to publish in

Palynology.)

D'Antoni, H. L.: Paleotemperatures of La Malinche:

A Palynological Hypothesis. Grana, vol. 32, 1993,

pp. 354-358.

D'Antoni, H. L.; Armstrong, R.; Coughlan, J.; Skiles,

J.; and Daleo, G. R.: Remote Sensing and

Palaeoecology in Southern Patagonia. Proceedings of the 3rd Symposium on South America,

Landscape Dvelopment, Paleoecology and Climate History of the Arid Diagonal of Southern

America in the Recent Quatemary, Bamberg,

Germany, July 1994.

D'Antoni, H. L.: Remote Sensing and Palaeoecology

in Southern Patagonia. Proceedings of the 3rd

Symposium on South America, Landscape

Development, Paleoecology and Climate History

of the Arid Diagonal of Southern America in the

Recent Quaternary, Bamberg, Germany, July

1994b. Paper accepted for publication in the

Bamberger Geographische Schriften.

D'Antoni, H. L.; Armstrong, R.; Coughlan, J.; Skiles,

J.; and Daleo, G. R.: Effects of Stratospheric Ozone

Depletion and Increased Levels of Ultraviolet

Radiation on Subantarctic Forests and Western

Patagonian Steppe: A Research Project in Stratospheric Ozone Depletion/UV-B Radiation in the

Biosphere, R. H. Biggs and M. E. B. Joyner, eds.,

NATO ASI Series I, vol. 18, Springer-Veflag,

Berlin, 1994, pp. 81-96.

D'Antoni, H. L.; Skiles, J.; Armstrong, R.;

Coughlan, J.; Daleo, G.; and Mayoral, A.: Plant

Responses to Increased UV-B Radiation: A

Research Project. The 5th Global Warming

International Conference and Expo, San

Francisco, Calif., Apr. 4-7, 1994. Abstracts: 92.

(Poster session with a booth devoted to the first

results of this project.)

D'Antoni, H. L.; and Spanner, M. A.: Remote

Sensing and Modern Pollen Dispersal in Southern

Patagonia and Tierra del Fuego (Argentina):

Models for Palaeoecology. Grana, vol. 32, 1993,

pp. 29-39.

Hansen, Henry Paul: Pollen Analysis and Postglacial

Climate and Chronology. Science Monthly [Early

Man in Oregon], vol. 62, no. 1, Jan. 1946,

pp. 52--62.

Sch/ibitz, F.: Holocene Vegetation and Climate in

Southern Santa Cruz, Argentina, Bamberger

Geographische Schriften, Bamberg, Germany, '

Bd. 11, 1991, pp. 235-244.

Keywords

Paleoclimate, Historical global change,

Paleovegetation, and Paleoecology

7
Schmidt-Cassegrain Long-Range Laser Velocimeter

Investigator(s)

Stephen E. Dunagan, Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

Many large scale aeronautical test programs that are

conducted in the National Full-Scale Aerodynamics

Complex (NFAC) wind tunnels require the measurement of localized regions of the flow field in order to

better understand the aerodynamic phenomena under

investigation. Laser velocimetry (LV) is an important

noninvasive method for measuring the air velocity at a

point. This study has been directed at the design and

fabrication of an instrument for the 40- by 80-Foot

Subsonic Wind Tunnel. Technical challenges include

test section access, adequate optical aperture, laser

power, and flow seeding techniques. Instrument

design parameters combine to determine the signal-tonoise ratio of the product instrument, which ultimately

determines the achievable data rates and therefore the

economic viability of the instrument.

Progress and results

A two-component, dual-beam laser velocimetry (LV)

system for the 40- by 80-Foot Subsonic Wind Tunnel

has been designed and fabricated and is undergoing

final testing in the optics lab. The instrument design is

based on the adaptation of commercial large aperture

Schmidt-Cassegrain telescope optics to simultaneously

perform the functions of focusing the laser beam pairs

to a beam waist intersection defining the measurement

(probe) volume, and collecting the back-scattered light

and focusing it through a spatial filter to an appropriate photodetector. Uncoupled orthogonal measurement of two coordinates of velocity may be made with

this instrument. To avoid the need for large, high

quality windows in the test section, the instrument has

been configured as a streamlined optical assembly

mounted to a traverse on the floor of the test section

and translated in the streamwise and cross-stream

directions.

The layout of the instrument is depicted in

figure 1. Single-mode polarization maintaining fiberoptics transmit light from the remotely located laser

into the optical assembly. The laser velocimeter probe

volume is translated in the vertical direction by means

of the zoom (focusing) feature of the primary mirror of

the telescope. The optical power combination of the

primary and secondary mirrors is ideal for creating a

small, high intensity probe volume. Coaxial backscattered light is collected through the same optical

system. The small probe volume and excellent imaging performance of the telescope optics permit this collected light to be spatially filtered through an

appropriately sized pinhole to reject unwanted light

scattered from outside the laser beam intersection volume, thereby improving the signal-to-noise ratio. This

spatially filtered signal is then conveyed via multimode fiber to a photomultiplier tube, and the electronic signal is analyzed with a commercially available

Fourier transform processor for Doppler shift. Frequency domain signal processing permits analysis of

Doppler burst signals with a very poor signal-to-noise

ratio.

A prototype optical system has been set up and

evaluated on the optics bench. Results have been

encouraging, with high signal-to-noise ratio as the

primary indicator. Some problems have been identified as well; in particular," the very small number of

fringes present in the probe volume is problematic for

the commercial digital Fourier-transform burst-signal

processor in use. A wind tunnel instrument has been

designed and fabricated based on the outcome of this

optical bench test. A stress analysis for the test section

mounted instrument pod and a small scale traverse

has been completed. Fabrication drawings have been

generated and the components have been fabricated.

The instrument has been assembled in the optics lab

and evaluated with a calibration velocity source and

an air jet flow field.

Significance of the results

Results of the instrument checkout prove the viability

of the design concept. This study has produced an

instrument suitable for on-demand use in a variety of

testing applications in the large NFAC wind tunnels.

Publications resulting from study

Dunagan, S. E.: A Long Range Schmidt-Cassegrain

Laser Velocimeter for Large Wind Tunnel

Applications. AIAA Paper 94-0019, to be presented

at the AIAA 33rd Annual Aerospace Sciences

Meeting, Reno, Nev., Jan. 1995.

Keywords

Laser Doppler velocimeters, Flow measurement,

Wind tunnels
Probe volume

LASER AND FIBER OPTIC COUPLERS

(MOUNTED OUTSIDE WIND TUNNEL)

6 Watt laser (Ar+)

Fiber optic couplers Prisms

Bragg cells

Mirrors

Single mode

fibers

Corrector

lens Secondary mirror

Fiber optic output collimators

" Collection lens It

Mirroi , _ Spatial

, m filter

Ii

OPTICAL PROBE ASSEMBLY (SIDE VIEW)

I (inPhotodetector control room)

Linear bearings

Spatial

__ "From laser

OPTICAL PROBE ASSEMBLY (TOP VIEW)

Figure 1. Optical layout for Schmidt-Cassegrain long- range laser velocimeter.

.
Detection of Life Forms: Extant, Dormant, or Extinct

Investigator(s)

Rosalind A. Grymes and Christine Sawyer,

Ames Research Center,

Moffett Field, CA 94035-1000

Jay Shafto, Pomona College,

Claremont, CA 91711

Objectives of the study

Researchers continue to be intrigued by questions

surrounding terrestrial evolution, by the reality of life

in extreme terrestrial environments, and by the possibility of extraterrestrial life. The fossil record and

extant unicellular organisms, like the Archaebacteria,

are links to the origins of life on Earth. Studies of

simple organisms surviving in environments such as

the Gobi Desert and the Antarctic ice fields enable us

to form hypotheses regarding the presence of life in

conditions nearly as harsh as those of some planetary

surfaces. In this project, we have applied one of the

newest and most powerful technologies of molecular

biology to the central difficulty scientists encounter in

the search for life-recognizing success. We have experimented with a technique that can detect both extant

and extinct life. The polymerase chain reaction (PCR)

enzymatically amplifies nucleic acids. With the particular exception of prions, all life on Earth is based on

the genetic code of the nucleic acids deoxyribonucleic

acid (DNA) and ribonucleic acid (HA). In PCR, a

thermostable DNA polymerase makes a faithful copy

of any DNA molecule-even DNA fragments can be

substrates. The 'chain' of the reaction's title refers to

the sequential rounds of molecular polymerization

that occur every 1-2 minutes for 20-30 cycles. Figure 1

shows schematically the amplification of a DNA

sequence by PCR. Amplifications on the order of

105-fold can be regularly achieved, and higher levels

of amplification are attainable if required.

From the space agency's viewpoint, the search for

life can more accurately be termed the search for

microscopic life or remnants of life. Larger forms of

plant and animal life are unmistakable, but are unexpected in extreme terrestrial and extraterrestrial environments. In dealing with microscopic organisms, the

techniques used for isolation and detection have

important limitations. Isolation from environmental

sampling requires cultivation and the maintenance of

an acceptable habitat. The environmental conditions of

thermal springs, deep sea trenches, desert rocks, and

Antarctic tundra are very difficult to faithfully recreate

in the laboratory. Each of these individual niches is

described by unique variables of moisture, pH, available oxygen, temperature, etc. NASA researchers face

an even more daunting challenge, as the conditions

required by extraterrestrial life forms are completely

unknown. In the area of detection, clinical techniques

are based on 1) the chemical detection of specific

products that can be associated with particular organisms, and 2) unique organismal metabolic requirements or capabilities. Researchers are not usually well

informed about the attributes of life forms that are rare

or alien.

The PCR offers two distinct advantages over the

more classic approaches described above. First, it

unites the detection of nucleic acids with their amplification. Even a single molecule of DNA is sufficient to

initiate the reaction. Second, it can detect any life form

using the DNA/RNA genetic code. No other information regarding metabolism, cultivation conditions, or

products is required. The power of this technology is

already being exploited by archaeologists in recovering the genetic code of organisms long extinct from

partial DNA residues in fossils. The requirements that

we have studied differ from those of most biological

historians, however. PCR depends on the initiation of

the reaction using a "primer' supplied by the experimenter. Usually, researchers are interested in a specific

DNA or RNA sequence, and will provide a primer

based on their knowledge of that sequence. We have

evaluated the utility of the PCR reaction using random

primers to identify unknown DNA sequences. Our initial investigations have focused on:

• selecting primer pairs that amplify an identifiable pattern from test bacteria;

• evaluating parameters affecting the results;

• determining the finest level of detection that

can be attained; and

• recovering detectable signal patterns from test

bacteria adsorbed to solid surfaces (soil

samples and soil sample mock-ups).

Progress and results

Selecting primer pairs that amplify an identifiable

pattern from test bacteria

Evaluating parameters affecting the results

The primers listed in table I were tested for their ability to amplify a ladder of DNA fragments from

genomic DNA isolated from Escherichia coli (E. coli), a

10
Unamplified DNA _llllllllllllllll[llllll [IIIIIIIII IIIIII!IIIIIIIU_o

Cycle 1

(F/VV

Denature and anneal primers

/VV

Jilttltiillli

m_mm_m__O

v_/V0

Primer extension

Cycle 2

Denature and anneal pdmers O-__

_itilliilllllnlllllllllllll|llllllllllll_ 0

0

/_111LIlLI LIUI li ! !!! l! I ! 111HULLIILLI£1-LII ! ! ! ! ! ! ! ! ! ! !_0

I

V

.mrn 

__0

0

lllllllllllll X/_/_/

Primer extension

/VV

OV',_/k_rfnlltltlttitillLLlJJIHiLILL_]ll_o

©

IltltttltlttllLLJ]H]JJlJJJLl_[[Jllllllii]l]J]] _/VV-- - _0

VVk/O

0

IlllllllllllllllllllllllllJJHIlllllllllllllllll

/VV

0

IIIttlllllllll]llliililtlmlllllliilllillltliliiiii_o

Cycle 3

Figure 1. Polymerase chain reaction.

11
Table I

Desi_Tnator Me_ting point, °C

RE-01 49

RE-02 45

RE-05 41

RE-06 41

RE-07 47

RE-10 44

RE-21 47

RE-22 43

RE-24 46

RE-25 41

RE-26 52

RE-30 47

At composition, percent Sequence

20 CGGGATCCGC

20 GCGGTACCCG

40 GCGAATTCCG

40 CGGAATFCGC

20 GGGATCCGCC

20 CCCTGCAGGC

20 GGCTGCAGCG

20 CCCTCGAGGC

20 GGTCGACGCG

20 CGAATTCGGC

20 CCGCATGCGC

20 CGCGAGCTCG

bacterium commonly found in soil and in the mammalian lower intestinal tract. This bacterium was

selected because it is frequently used in laboratory

investigations for genetic engineering applications,

and the strain used had been mutated so that it was

entirely dependent on nutrients supplied in the

laboratory. This strain would be unable to survive in

the wild. The primers were selected because they have

compatible melting points. The thermal energy

required to disrupt duplex DNA, to 'melt' it apart,

depends on the relative amounts of the four bases

(A = Adenine, T = Thymidine, G = Guanine,

C = Cytidine) that make up a particular DNA

sequence. The strongest duplex bonding occurs

between G and C, so higher percentages of A/T correlate with lower melting points. Temperature selection

is an important part of the PCR process, as detailed

below.

The PCR process contains fundamentally four

steps that operate on the required components. The

components are:

• substrate DNA (E. coli genomic DNA)

• primer (one of the primers above)

• nucleic acid building blocks (adenine,

thymidine, guanidine, cytidine

deoxyribotriphosphates)

• thermostable DNA polymerase

• magnesium (a required co factor of the

enzyme)

The required steps are"

• heat the reaction (denature the substrate)

• cool, and maintain at the annealing temperature that permits association of the primer

with the substrate

• step to the temperature that allows efficient

operation of the DNA polymerase, and stay at

that temperature long enough to elongate the

product DNA

• repeat this cycle, producing a doubling of

product in each round

The first analysis of 12 primers resulted in successful amplification of resolvable fragments in 6 of the

reactions. Amplified fragments result when the supplied primer pairs with the substrate DNA stably and

within a distance of approximately 2,000 bases. The

resulting amplified sequences are resolved by size and

electrical charge (the molecules have a negative

charge) by electrophoresis in agarose gels. Figure 2

shows, on the right, a cartoon of the electrophoresis

hardware, with the positive and negative electrodes

indicated. A gel of agaro_e is cast on the middle platform, and the gel is submerged in a buffer solution.

DNA containing samples are loaded in the wells, and

the resulting separation by size and charge that occurs

by electrophoretic molecular sieving is indicated by

the gel caricature on the left. DNA from different

strains of E. coli amplified in the PCR process using

the same random primer could yield the patterns indicated. Individual bands are assigned molecular sizes

by comparison to bands of known size (markers) run

in the adjacent land on the far right of the gel. Subsequently, we evaluated the contribution of magnesium

concentration and annealing temperature to the amplification reaction. We determined that a magnesium

concentration of 3.5 mM (high relative to many PCR

protocols) was optimum in our system. At this level,

the reactions produced both strongly amplified fragments and lesser quantities of more weakly amplified

products. The experimenter can choose whether s/he

wishes to see a complete 'catalog' of amplified fragments (high magnesium) or a more selective assortment of the most highly amplified fragments only (low

12
+

+

0

4. 4. G" . G_

c------1 r-------l c--------_ r----------n

Figure 2. Diagrams showing the nature of electrophoretic molecular sieving analysis.

magnesium). Alterations of temperature similarly

produce low levels of minor amplification products in

addition to the main products seen under stringent

conditions. This is due to altered binding of primer

encouraged by the less stringent annealing temperatures, which allows more 'breathing" in the duplex

pairs (primer:substrate).

Determining the finest level of detection that can be

attained

This task was approached in two ways. First, nucleic

acid that was isolated from E. coli cultures was used to

prime amplification reactions, and serial dilutions

were evaluated. In this way, we determined that as litfie as 0.5 nanogram of added substrate DNA resulted

in the production of predicted fragment profiles using

our standard conditions. Further sensitivity can be

acquired by altering magnesium concentration and

temperature, as discussed above, or by using the

products of the amplification reaction as the substrate

for a subsequent amplification process (sequential

amplifications). Second, we tested the robustness of

the PCR reaction by supplying the input DNA in its

native packaging--we directly added samples of

overnight broth cultures of E. coli to the reactants. The

bacteria were Iysed directly in the reaction mixture

using an initial high temperature step (lysis by boiling). In this way, we were able to detect amplification

products from as little as one microliter of an overnight culture. We also tried to correlate direct quantitation of bacteria (colony counting by placing a

measured quantity of the liquid culture onto a solid

substrate), spectr0photometric quantitation of bacteria

(measurement of light-scatter at 600 nanometers), and

PCR quantitation of bacteria (detection of amplification products). We found that direct colony counting

required high sample dilutions to allow efficient visual

counting, whereas spectrophotometry had a very short

linear range, and could not detect highly diluted

samples. In our hands, direct quantitation by PCR also

had a limited effective range. One microliter of an

overnight culture typically contains 100 bacteria.

Volumes greater than 40 microliters could not easily be

accommodated by our reaction mixture. We tested

several volumes between I and 40 microliters, with no

amplification success. We believe this is caused by

overloading the reaction mix with bacterial lipids and

proteins. In sum, the three methods of bacterial

quantitation described overlap in utility, but no two

had superimposed reliability ranges.

Recovering detectable signal patterns from test bacteria adsorbed to solid surfaces (soil samples and soil

sample mock-ups)

Several different approaches were tried in the mockup test. They were based in published protocols used

to analyze soil bacteria or to evaluate PCR sensitivity

in the arena of soil testing. Very little information

I3
regarding the soil makeup was presented. Fundamentally, these procedures involve

• lysis of bacteria in the sample by heating, or

no lysis, followed by

• emulsification of the soil sample in the presence of high calcium levels

• the addition of an equal volume of a high density material and

• low speed centrifugation of the sample.

The protocol is designed to release the bacterial

particles from the soil, and have them float to the top

of the density gradient during the centrifugation step,

while the heavier soil solids form a pellet. We tried

this procedure, and minor modifications, several times

without success. The soil we used did not pellet

cleanly, and there were major losses in bacterial viability. This may be due to osmotic shock as the bacteria

are admixed with the high density fluid. We noticed a

strong similarity between this protocol and the use of

pure hydroxyapatite to bind DNA under specific ionic

conditions. In thes_ procedures, the nucleic acid is

separated from complex mixtures by adsorption to the

hydroxyapatite and is released by washing the bound

complex with solutions of progressively changing

ionic strength. We accordingly generated a protocol

for the isolation of bacterial DNA from inoculated soil

samples and raw samples patterned on hydroxyapatite

resolution of DNA in mixed samples. This approach,

too, was unsuccessful. It is clear to us that at this point

we need additional expertise from geochemists to

properly develop separation protocols that are capable

of recovering fragments of nucleic acid from soil

samples. The soil itself has ionic and colloidal properties that strongly affect our ability to manipulate

adsorbed or admixed DNA. Existing laboratory procedures accommodate crude cell extracts, but are not

robust enough to deal with the 'dirty" mixtures of soil

sampling.

Significance of the results

We have demonstrated the applicability of PCR amplification to the study of samples containing unknown

DNA sequences using the random priming approach.

The efficiency and sensitivity of the process appear to

be adequate to the task of detecting life in extreme

environments. Water samples should present very little difficulty, but solid samples require methods of

nucleic acid extraction. At the present time, these

methods are beyond our expertise, although we are

confident that this difficulty could be surmounted

with only the addition of new technical expertise. We

hope that this laboratory will continue to exist as a

source of molecular biology tools to the NASA

community.

Keywords

Random primed polymerase chain reaction (PCR),

Molecular biology, Search for life

14
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,

Ames Research Center

Oswaldo Garcia and Patricia Foschi,

San Francisco State University,

San Francisco, CA 94132

Steve Gaines, Sterling Soft'rare,

Ames Research Center

Objectives of the study

Polar stratospheric clouds (PSCs) occur during the

polar winter when temperatures in the stratosphere

fall to levels low enough to saturate the air with

respect to nitric acid and/or water. The role that PSCs

play in the chemistry of ozone depletion and the formation of the Antarctic ozone "hole" has been well

documented (McCormick et al., 1982; Solomon et al.,

1986; Turco et al., 1989; Hamill and Toon, 1991). PSCs

provide the surfaces upon which heterogeneous reactions occur that ultimately lead to the destruction of

ozone. The timing of the onset and duration of PSCs,

as well as their geographic extent, are not well

understood.

To date, no extensive or detailed climatology of

PSCs has been assembled. Such a climatology would

be an important tool in the study of ozone depletion in

the polar regions and would establish baseline

conditions from which changes in the frequency and

occurrence of these clouds could be measured. Such

changes may arise naturally or from human activity,

such as the injection of nitric acid and water vapors

into the stratosphere by future supersonic aircraft.

The relative lack of traditional meteorological

observations in the Antarctic region makes it necessary

to rely on satellite data in order to construct a longterm climatology of PSCs. The advanced very high

resolution radiometer (AVHRR) sensors onboard the

National Oceanic and Atmospheric Administration

(NOAA) polar-orbiting satellites have been collecting

data over the polar regions since 1979 (Burroughs,

1991). These operational satellites, with their excellent

temporal and spatial coverage of polar regions, could

be used to establish a PSC climatology if a means were

found to reliably detect the presence of PSCs using

AVHRR data.

Conventional wisdom (Yamanouchi et al., 1987;

Ebert 1987a,b, 1989; Welch et al., 1992) held that

AVHRR imagery is not suitable for PSC detection

because these clouds occur during the polar winter

and early spring, when little or no sunlight is present,

thus making reflected channels useless. In addition,

many PSCs are optically thin and occur against a cold

background. Therefore there is often little thermal

contrast between PSCs and the surface, making it very

difficult to detect PSCs using infrared AVHRR data. "

Recent research in the fields of remote sensing and

image processing, however, has shown that AVHRR

data can be successfully used to identify a variety of

clouds over the polar regions using multispectral data

(Yamanouchi et al., 1987) and various patternrecognition algorithms based on spectral and textural

features (Ebert 1987a, b, 1989; Key 1990; Welch et al.,

1992). Ebert (1987b) took the first steps in the development of an algorithm that specifically identifies

optically thick PSCs among 17 other categories of

clouds. This algorithm, however, was only applied to

data for a few days over both polar regions.

The objectives of this study are to determine

whether AVHRR data can be used to detect both optically thick and optically thin PSCs over Antarctica for

an entire season (1992). Information from the analysis

of an entire season will be used to construct an automated classification scheme for the identification of

PSCs. The development of an automated PSC detection scheme will allow processing of the entire record

of AVHRR data in order to assemble a long-term climatology of PSCs.

Progress and results

AVHRR data obtained from the Arctic and Antarctic

Research Center at the Scripps Institution of

Oceanography was processed at the Ames Research

Center using the Ames Meteorological Satellite Downlink and Display System. Several hundred AVHRR

channel 5 (12 micron) images for the period of

April-October 1992, were processed. NOAA AVHRR

channel 5 data frequently contain random scanner

15
noise, randomly scattered single pixels, or small

patches of pixels with anomalous values that are much

darker or brighter than their neighbors. These anomalous pixel values are usually radiometrically corrected

by globally using a median filter. Although this process is acceptable for most applications, the need to

preserve the subtle differences in original values

necessitated the development of another method. The

new method uses two filters in tandem: one to mark

anomalous pixels, selecting them by a local-difference

algorithm, and a second to radiometrically correct only

the marked pixels, using a median filter. Once the

imagery was filtered, calibrated, and registered, temperatures in the PSC ranges were highlighted in color,

and the evolution of these temperatures over an entire

season (1992) was studied.

As surface temperatures in Antarctica can fall to

PSC range, surface automatic weather station (AWS)

data (Charles Steams, University of Wisconsin, personal communication) and available National meterological Center (NMC) sounding data were used to help

distinguish surface temperatures from tropospheric

and stratospheric temperatures. Stratospheric temperature and aerosol extinction coefficient data from the

cryogenic limb array etalon spectrometer (CLAES)

instrument (John Mergenthaler, Lockheed Missiles &

Space, Inc., personal communication) were also used

to verify the results from the AVHRR temperature

analyses.

Imagery from the 1992 season was analyzed and

then divided into one of the four following categories

for future study: 1) no PSCs--AVHRR temperatures

represent cold Antarctic surface; 2) optically thick

PSCs evident in the AVHRR imagery; 3) optically thin

PSCs evident in the AVHRR imagery when verified

with ancillary data sets; and 4) no PSCs evident in the

AVHRR imagery, but PSCs are evident in the ancillary

data sets.

From the initial analysis, it was determined that

optically thick, and some optically thin, PSCs are easily

identifiable in the imagery collected at Palmer Station,

a station that collects AVHRR data for an area

covering the Antarctic Peninsula and the Weddell Sea

(approximately the area from 0° to 90°W, south of 60°).

Type III PSCs (wave cloud PSCs) typically appear over

the Weddell Sea, downwind of the topographic relief

of the Antarctic Peninsula. The thermal contrast

between PSCs and the underlying clouds and ground

is the greatest in this region as compared to the colder

interior portions of the continent, a fact which aids in

the detection of PSCs.

Based on the results above, it was determined that

image segmentation by geographic region would be

the first step in the automated classification

procedures. Various analyses of the imagery from

Palmer Station have been performed to gather

information to be incorporated into the automated

classification scheme. The initial analysis of the data

consisted of thresholding of PSC temperatures,

constructing time series graphs, and compositing of

images to show before, during, and after PSC events.

Three threshold temperatures (200 K, 195 K and

188 K) that encompass the brightness temperatures of

both opaque and semitransparent PSCs were chosen.

Areas with brightness temperatures colder than the

selected thresholds were then identified and mapped

for every AVHRR image collected at Palmer Station

during August 1992. Time series graphs of the areal

coverage of temperatures below each threshold were

then constructed. This gave initial information on the

overall temporal variability of PSC coverage for the

region and guided the selection of particular time

periods for compositing. Four PSC events were noted

during August 1992. Images representing the before,

during, and after PSC events were composited in order

to yield information about the geographical distribution of the onset, evolution, and decay of PSCs in that

region.

The second phase of analysis has begun; it consists

of using neural networks for pattern recognition to aid

in the identification of PSCs. Again, using AVHRR

channel 5 data collected during August 1992 at Palmer

Station, 62 files were assembled. Each file is a mosaic

of the images collected for each 12 hour period that

month. Where images overlapped, the minimum value

of the various images was chosen. This process yields

data sets that are more interpretable by visual inspection and by computer processing with a neural net.

Using software that allows for a hypertemporal analysis of the channel 5 data, the time series of each pixel

(temperature evolution over time) is plotted to identify

the pattern and duration of PSC episodes. This information will be used to train a backpropagation neural

network to locate PSC episodes by an automated

method. The output from the neural network will be

mapped to show the timing and geographic extent of

each episode.

CLAES data were used to verify the presence of

PSCs in both the analyses described above. CLAES

data, and data from various other sensors aboard the

Upper Atmospheric Research Satellite (UARS) will be

used to verify the presence of PSCs in the AVHRR

data for the entire 1992 season. Analyses of the

AVHRR data will be expanded to cover the entire

region of Antarctica for the 1992 season. The information gathered from the joint analyses of AVHRR and

UARS data will be used to construct the automated

classification scheme for PSC detection.

16
Significanceof the results

The results from this initial study have shown that

optically thick PSCs, and a portion of optically thin

PSCs, can be readily identified in AVHRR imagery

collected at Palmer Station, Antarctica. As the analysis

of AVHRR is expanded to cover the entire Antarctic

region, and various techniques such as neural networks, multispectral analysis, and textural analysis are

incorporated, an automated classification scheme for

PSC detection can be developed. This will enable the

construction of a long-term climatology of PSCs. Such

a climatology would enable researchers to begin to

answer questions about the timing, onset, and duration of PSCs, as well as questions concerning their

geographic extent and annual variability.

Publications resulting from study

Pagan, K.; Garcia, O.; Foschi, P.; Mergenthaler, J.;

Kumer, J.; Roche, A.; Gaines, S.; and Hipskind,

R. S.: Detection of Polar Stratospheric Clouds over

Antarctica Using AVHRR, CLAES, Radiosonde

and Surface Automatic Weather Station Data. Seventh Conference on Satellite Meteorology and

Oceanography, Preprint Volume, Monterey, Calif.,

June 1994, pp. J19-J22.

Garcia, O.; Pagan, K.; Foschi, P.; Gaines, S.; and

Hipskind, R. S.: Detection of Polar Stratospheric

Clouds Over Antarctica Using AVHRR Images

Obtained at Palmer Station During August 1992.

Under review by the Polar Record.

In addition, the results of this study have been

presented at: Poster at High-Speed Research Program/

Atmospheric Effects of Stratospheric Aircraft (HSRP/

AESA) annual review meeting at Virginia Beach in

June 1993; poster at Ames DDF session and Dryden in

November 1993; poster at AGU annual meeting in San

Francisco in December 1993; poster at 3rd Circumpolar

Symposium on Remote Sensing of Arctic Environments in Fairbanks, Alaska, in May 1994; and a

presentation at Ames Birds of a Feather Image

Analysis Group in August 1994.

References

Burroughs, W. J.: The Development of Satellite Meteorology, chapter 3, Watching the World's Weather.

Cambridge Univ. Press, 1991.

Ebert, E. E.: A Pattern Recognition Technique for Distinguishing Surface and Cloud Types in the Polar

Regions. J. Climate Appl. Meteorol., vol. 26, 1987a,

pp. 1412-1427.

Ebert, E. E.: Classification and Analysis of Surface and

Clouds at High Latitudes from AVHRR Multispectral Satellite Data. Ph.D. thesis, University of

Wisconsin-Madison, 1987b.

Ebert, E. E.: Analysis of Polar Clouds from Satellite

Imagery Using Pattern Recognition and a Statistical Cloud Analysis Scheme. J. Appl. Meteorol.,

vol. 28, 1989, pp. 382-399.

Hamill, P.; and Toon, O. B.: Polar Stratospheric Clouds

and the Ozone Hole. Physics Today, vol. 44, no. 12,

1991, pp. 34--42.

Key, J.: Cloud Cover Analysis with Arctic Advanced

Very High Resolution Radiometer Data: 2. Classification with Spectral and Textural Measures. J.

Geophys. Res., vol. 95, 1990,

pp. 7661-7675.

McCormick, M. P.; Steele, H. M.; Hamill, P.; Chu,

W. P.; and Swissler, T. J.: Polar Stratospheric

Cloud Sightings by SAM II. J. Atmos. Sei., vol. 39,

1982, pp. 1387-1397.

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.

Turco, R. P.; Toon, O. B.; and Hamill, P.: Heterogeneous Physiochemistry of the Polar Ozone Hole. J.

Geophys. Res., vol. 94, 1989,

pp. 16,493-16,510.

Welch, R. M.; Sengupta, S. K.; Goroch, A. K.;

Rabindra, P.; Rangaraj, N.; and Navar, M. S.: Polar

Cloud and Surface Classification Using AVHRR

Imagery: An Intercomparison of Methods. J. Appl.

Meteor., vol. 31, 1992, pp. 405-420.

Yamanouchi, T.; Suzuki, K.; and Kawaguchi, S.: Detection of Clouds in Antarctic from Infrared Multispectral Data of AVHRR. J. Meteorol. Soc. Japan,

vol. 65, 1987, pp. 949-961.

Keywords

Polar stratospheric clouds, AVHRR satellite imagery,

Remote sensing and image analysis

17
Ablating Surface Heat Transfer Estimation for Flight

Application

Investigator(s)

Greg Noffz and Mike Bowman,

Dryden Flight Research Center,

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 fring 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

thrusts. 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-capacitance (RLC) "load" at the

end of a waveguide, has beert 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 coefficient 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, which together with the gage

form the RLC termination, were attached to the backside of the circuit board. Preliminary tests were per°

formed 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 everything is surrounded by a metal casing. The RLC termination is connected to a coaxial cable through a modified male bayonet navy connector (BNC). The entire

assembly is potted with room temperature vulcanizing

(RTV). The 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.

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 printed circuit (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 thickness of 0.0, 0.010, 0.020, 0.030, and

0.050 in. are simulated f-or each gage geometry.

Figure 2 shows the results from two gage geometries,

one with a conductor width of 0.005 in. and gap width

of 0.020 in. (5.20) and one with a conductor width of

0.010 in. and 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.-O.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 was also observed in lab tests.

Twenty second generation gages with thirteen different sensing element geometries have been lab tested

using the waveguide/RCB arrangement. Delrin shims

of various thicknesses were used to simulate the

18
• • ] •

Figure 1. Second generation packaging system.

ablator. Although manufacturing problems (warping

and tapering) with the shims have prevented us from

obtaining true "Delrin calibrations" for the candidate

gages, nevertheless the same trends evident in the

finite element modeling were present in the test data.

One of the better examples (i.e., wider conductor

widths and gaps) is shown in figure 3. RCB output

versus Delrin shim thickness is shown for two gages,

both with conductor and gap widths of 0.040 in.

(1 mm). Gage sensitivity drops off for shims thicker

than about 1.5 mm. 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.

Tests with a commercially available ablator were

conducted using the test panel shown in figure 4. The

gages were installed in the panel and the ablator

applied over them. Ablator thickness was measured

with a dial indicator. This test pointed out the need to

coat the gage face to prevent the ablator fromentering

the region directly between the "plates" of the capacitive gage and overloading the RCB. This problem does

not occur with the rigid shims. Qualitative tests of the

gage's sensitivity to temperature gave encouraging

results with regards to the gage components and output, but the present configuration uses materials such

as Delrin, circuit board material, and RTV, which tend

to expand, thus pushing the gage face slightly out of

the metal casing. The above tests illustrate the need for

the next gage configuration: metallic gage patterns

deposited in very thin layers (tens of microns) on a

high temperature ceramic.

19
, r _ = , I- ,

i ! ...: ! _ i i i

ill ! !i i

i!ii iiii!i ii

...... i........ i.... _ "i>i ........ _.... i..... i...... !....... i..... i......t....... i........ i.... t....i....... i.... t....... !........ !.... t....... !...... i..

ilE IF: _ iilii

! _! _ _IIU! ! ! : : : : "

d..i !_ b--.:: i I i i i ! ! ! i I I

i i_i i d.. i i i i

T i i ,= i i i i i i i i

i i i I,,_Y_.-! i , , i i i

I _ I_" : __ : : : : : : _ : : :

, ._ : : , i ! i i } i , , i i ......

...."....... '...... :......................... _..... _...... [....... i...... _..... "......... i i i _ ie

o i i , _ i i i i i i iiE: i i

.... _ : : ' : : ' i i°._ " i i

_1' i _ i i i_ _,

-, !i

(,,.; (_ _ _i ('J (',J

I./'I

0

d

d

0

d

0

uJo/_-Id 'eoue_,!oedeD

2O
4OO

3OO

E

©

200

IO0

0

0 OiS 1 1.5 2 2.5

Shim Thickness, mm 40.40 #015

40.40 #016

Figure 3." Shim test results: RCB output for gage geometry 40.40 (gages 015 and 016).

21
Figure 4. Test panel.

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.

Significance of the results

Finite element 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, but is not

ready for high temperature tests. Results so far indicate that this gage concept has the ability to measure

thickness changes in the range and to the resolution

equired. 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

naphthalene and wing ice detection.

Publications resulting from study

Noffz, Gregory: Development of a Capacitive Gage for

Measuring the Recession of a Thin-Layered

Ablator. Master's Thesis, University of California

at Los Angeles, 1994.

Keywords

Ablation measurement, Thin film measurement

22
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

Ute Fischer, Kimberly Jobe, and Michael Wich,

San Jose State University Foundation,

San Jose, CA 95192

Objectives of the study

Of fatal air transport accidents between 1983 and 1987,

47 percent 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 decision making, 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 vulnerabilities and types of errors

crews are likely to make

• Describe effective decision making strategies

Progress and results

The first year of this project involved three major

tasks: development of a taxonomy of decision types,

characterization of decision errors, and identification

of effective decision strategies. Building on this effort,

three integrated activities were undertaken in the sec _

ond year.

• A generic process model of decision making in

dynamic environments was developed.

• The dimensions that distinguish decision

types were validated through a sorting study conducted with professional pilots from two airlines.

• Effective decision strategies were verified in a

full-mission simulator study that also examined the

effects of automation on crew performance.

These efforts have yielded the following products

and conclusions:

1. All decisions in dynamic situations involve

two general processes: situation assessment and

response selection. Situation assessment involves

defining the nature of the problem, the levels of risk

inherent in the situation, and the amount of time that

is available for dealing with the problem. If the nature

of the problem is not clear, diagnostic efforts may be

needed, time permitting. Response selection means

choosing a course of action, a process that may vary

depending on whether responses are readily available

as rules, whether several options must be evaluated, or

whether one or more options must be created where

none previously existed. The amount of work that

must be done to make a decision will depend on how

unambiguous the cues are that define the problem and

what kind of response options are present in the

situation.

2. The notion that situation ambiguity and

response availability determine the amount and kind

of work demanded and that time pressure and risk

levels are multipliers was developed in a bottom-up

fashion, through analysis of crew performance in

response to various decision situations. To validate

these dimensions, a sorting study was conducted with

professional pilots from two different airlines that fly

in very different weather and terrain conditions. Individual pilots were given brief written flight problem

scenarios (taken from our Aviation Safety Reporting

System (ASRS) decision event database) and asked to

sort them into piles that represent similar kinds of

decisions they might have to make if they were in

those situations. Participants differed in role (captain,

first officer, and flight engineer) as well as experience

levels. Sorting data were subjected to multidimensional scaling and clustering analyses, done separately

for each crew role. These analyses confirmed the

dimensions previously identified. However, they also

highlighted important differences in perspective associated with cockpit role, as shown in figure 1. Captains, who have the responsibility for making difficult

decisions, focused on risk (both immediate and future)

as their primary dimension, whereas this factor was

not salient in the other crew positions. Time pressure

was relevant to all crew positions. First officers and

flight engineers are more concerned with the basis of

decisions and with the information that would go into

a decision, as befits their roles in the cockpit. Similar

findings were found in both airline samples, further

supporting the validity of the dimensions and establishing their generality despite differences in everyday

practical experience.

23
3. Data collected in a full-mission simulator

study were analyzed to determine whether effective

crew strategies previously identified were also evident

in a different flight scenario. This simulator study was

originally designed to assess the effects of cockpit

automation on crew coordination, communication,

and performance (errors). We examined strategies in

four episodes that varied in the types of demands they

placed on the crew and the types of decisions required:

(a) preparation for a "missed approach" on landing,

(b) entry into a nonpublished holding pattern,

(c) management of a generator-related system failure,

and (d) a decision about whether and where to divert

because of bad weather at the original destination. Our

analyses confirmed previous findings about effective

crew strategies: More effective crews showed higher

levels of situation awareness, planning, task completion (e.g., abnormal checklist procedures), and task

management (e.g., buying time to make decisions, not

being rushed). These held across both levels of

automation. Automation affected performance by

slowing down crews' understanding of the nonpublished holding pattern and getting established in the

hold. Indirect effects were found in management of the

system failure, where the automation seemed to distractcrews and lower their monitoring of the degrading system and completion of checklists. It may have

also distracted crews from more thorough information

gathering and systematic reasoning as they made the

diversion decision.

4. In addition to the above new findings, a

database has been completed of 96 flight incidents

from the ASKS that involve crew problem solving or

decision making. These have been coded in terms of

the precipitating event, phase of flight of the precipitating event, nature of resulting decisions, phase of

flight of resulting decisions, taxonomic classification of

resulting decisions, and levels of ambiguity and time

pressure in the situations. This computerized database

can be accessed by individuals seeking certain classes

of events for research or training purposes. A user's

manual has also been prepared and is undergoing

final revisions prior to distribution.

Significance of the results

We are beginning to understand the characteristics of

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

and crews" responses to those situations. This research

is already serving as the foundation for crew training

in decision making by several airlines, and it may also

be useful in designing systems to support crew decision making in situations that might cause them difficulty and where errors are likely.

Publications resulting from study

Orasanu, J.: Shared Problem Models and Flight Crew

Performance. Aviation Psychology in Practice,

N. Johnston, N. McDonald, and R. FuUer,'eds.,

Ashgate Publishing, Aldershot, U.K., 1994,

pp. 255-285.

Orasanu, J.; Dismukes, K.; and Fischer, U.: Decision

Errors in the Cockpit. Proc. of the Human Factors

and Ergonomics Society 37th Annual Meeting,

Santa Monica, Calif., 1993, pp. 363-367.

Orasanu, J.; and Fischer, U.: Finding Decisions in

Natural Environments: Toward a Theory of

Situated Decision Making. To appear in

Naturalistic Decision Making, C. Zsambok and G.

Klein, eds., Lawrence Erlbaum Associates,

Hillsdale, N. J.

Orasanu, J.; and Strauch, B.: Temporal Factors in

Aviation Decision Making. Proc. of the Human

Factors and Ergonomics Society 38th Annual

Meeting, Santa Monica, Calif., 1994.

Presentations

Orasanu, J.: Pilot Decision Making: Meeting the

Challenge of Abnormal and Emergency Events.

Presented at the 22nd Technical Conference on

Human Factors in Aviation sponsored by the

International Air Transport Association, Montreal,

Canada, Oct. 1993.

Orasanu, J.; Dismukes, R. K.; and Fischer, U.: Decision

Errors in the Cockpit. Presented in a Panel on

Analysis of Error in Complex Decision Making

Tasks at the 37th Annual Meeting of the Human

Factors and Ergonomics Society, Seattle, Wash.,

Oct. 1993.

Orasanu, J.: Discussant in a Symposium on Training

for Team Coordination and Decision-Making

Effectiveness: Theory, Practice, and Research

Directions. Presented at the 37th Annual Meeting

of the Human Factors and Ergonomics Society,

Seattle, Wash., Oct. 1993.

Orasanu, J.: Shared Problem Models and Flight Crew

Performance. Presented at the Western European

Association for Aviation Psychology Conference,

Dublin, Ireland, Mar. 1994.

Orasanu, J.: Decision Making in Action: Meeting the

Challenge of Emergency Events. Presented at the

Third Offshore Installation Management

Conference sponsored by the Robert Gordon

University, Aberdeen, Scotland, Apr. 1994.

Orasanu, J.: Group Interaction and Crew Performance.

Lecture in _ul"se on Life in Space, Stanford

University, Palo Alto, Calif., May 1994.

24
Orasanu, J.: Expert Decision Making in Flight

Operations. Presented at the International Civil

Aviation Organization (ICAO) Regional Safety

Seminar in Amsterdam, The Netherlands, May

1994.

Orasanu, J.; and Fischer, U.: Finding Decisions in

Natural Environments. Presented at the Second

Conference on Naturalistic Decision Making,

Dayton, Ohio, June 1994.

Orasanu, J.: Training for Decision Making in

Abnormal and Emergency Events. Presented at the

International Civil Aviation Organization (ICAO)

Regional Safety Seminar, Addis Ababa, Ethiopia,

Oct. 1994.

Orasanu, J.; and Strauch, B.: Temporal Factors in

Aviation Decision Making. Presented at the

Human Factors and Ergonomics Society meeting,

Nashville, Tenn., Oct. 1994.

Invited consultation

Orasanu, J.: Invited by the National Transportation

Safety Board to be an Expert Witness on Crew

Decision Making for an Accident Investigation,

Charlotte, N.C., Sept. 1994.

Orasanu, J.: Methods of Coding Team Decision

Making in Complex Dynamic Environments.

Presented at a workshop on Team Performance

Assessment Techniques (TPAT-1) sponsored by

the University of Maryland School of Medicine

Trauma Center Research Team, Baltimore, Md.,

July 1994.

Keywords

Dynamic decision making, Team decision making,

Situation assessment

25
Analysis of Arc-Jet Wind Tunnel Vacuum Ultraviolet (VUV)

Experiment

Investigator(s)

Chui Park, Ames Research Center,

Moffett Field, CA 94035-1000

Dikran S. Babikian, Thermosciences Institute,

Ames Research Center

Problem

When an entry vehicle flies through the atmosphere at

a super-orbital speed, radiation emitted by the hot

shock layer around the vehicle becomes a major source

of heating of its heat shield. There is an uncertainty as

to what fraction of the radiation energy is contained in

the vacuum ultraviolet (VUV) wavelength range

below 200 nm. To answer this question, an expriment

was carried out in 1992 in one of the 20-MW arc-jet

wind tunnels in which radiation falling onto the

stagnation point of a 15 cm diameter, fiat circular disk

was measured spectrally from the VUV to the long

wavelength limit of the visible radiation. The data had

not been analyzed. One reason was the fact that the

state of the gas flow produced in an arc-jet wind

tunnel was unknown because of the strong thermochemical nonequilibrium phenomena occurring in the

flow. In order to understand the flow conditions,

additional spectroscopic measurements, of both the

nozzle flow and the shock layer flow from the sideview positions, were also conducted in 1992. The data

obtained from these experiments had not been

analyzed either.

Objectives of the study

The objectives of the research were: 1) to characterize

the flow produced by the arc-jet wind tunnel to enable

rational analysis of the VUV radiation data at the stagnation point, and 2) to compare the experimental and

calculated spectral radiation intensities. These objectives required: 1) calculation of the characteristics of

the arc-heater, 2) calculation of the thermochemical

nonequilibrium processes in the nozzle, 3) calculation

of the radiation emitted by the nozzle flow and comparison with the side-view experimental data,

4) calculation of the therrnochemical nonequilibrium

processes in the shock layer over the tested model,

5) calculation of the radiation emitted by the shock

layer and comparison with the side-view experimental

data, and 6) calculation of radiation incident on the

stagnation point and comparison with the

experimental data.

Progress and results

As mentioned above, three different sets of spectroscopic data obtained in the 20-MW arc-jet wind tunnel

had to be anlyzed: 1) the spectra emitted by the freestream flow at the nozzle exit, 2) the side-view spectra

of the shock-layer radiation emitted in the direction

normal to the stagnation streamline of a fiat-disk

model at various distances from the model surface,

and 3) the spectra of the shock-layer radiation incident

on the stagnation point of the model. The working gas

in all these tests was mostly air containing a small

amount of argon.

The computations were made in four steps as follows: 1) the characteristics of the arc-heater were computed using the ARCFLO code; 2) the flow along the

centerline of the nozzle of the arc-jet tunnel was calculated using the multitemperature one-dimensional

nonequilibrium code NOZNT; 3) the flow over the test

model, including the nonequilibrium thermochemical

region behind the bow shock wave, was calculated

using three different codes; a) a two-temperature onedimensional nonequilibrium code NONEQ, b) a twotemperature two-dimensional nonequilibrium code

2D2T, and c) a second two-temperature twodimensional nonequilibrium code NEQ2DBLNTB,

which did not include argon and therefore did not

simulate the arc-jet flow conditions correctly; however

it was used as a check of the 2D2T code; 4) and the

spectral intensities were calculated using the radiation

code NEQAIR.

These calculations found the following:

1. The mass-averaged enthalpy given by the

ARCFLO code is slightly lower than the centerline

enthalpy.

2. The NOZNT code solution based on the centerline enthalpy deduced from heat transfer measurements predicts the thermochemical nonequilibrium

state in the test section of an arc-jet wind tunnel fairly

well.

3. The NOZNT code closely reproduces the measured translational-rotational temperatures and the

vibrational temperatures of the arc-jet free stream, and

it underpredicts the electron-electronic temperature

when compared with the measured values.

4. The NEQAIR code correctly reproduces

intensities of most atomic lines but underpredicts

those of the continua and molecular bands.

5. The NEQAIR solution based on the flow field

calculated using the one-dimensional code NONEQ

26
reproduces the relative intensity distribution fairly

closely.

6. An equilibrium region is found in the shock

layer over a 15 crn fiat disk model when the stagnation

pressures is 0.003 atrn or higher. By analyzing the

radiation emitted by this equilibrium region, flow

enthalpy was determined.

7. The radiation spectra incident on the stagnation point of a model placed in an arc-jet wind tunnel

cannot be calculated using the existing computer

codes, at least for the tested condition.

8. The VUV component of the radiation incident

on the stagnation point is very small.

Significance of the results

We can assess the state of our knowledge about the

nature of the flows produced in arc-jet wind tunnels

and about the nature of radiation as follows: 1) The

nonequilibrium relaxation process in the nozzle of an

arc-jet wind tunnel is fairly well known; 2) The nonequilibrium relaxation process behind a shock wave in

front of a model placed in an arc-jet wind tunnel is not

well known; and 3) an equilibrium region can be produced in the shock layer over a blunt body by appropriately designing the model and operating the facility

in a certain way. Enthalpy of the flow can be determined by analyzing the radiation emitted by the shock

layer. We are encouraged to pursue development of an

instrument to measure enthalpy using the principle

discovered by this work. Additionally, the knowledge

that the VUV contribution to total radiation is small

will settle a controversy that has lasted for over

30 years.

Publications resulting from study

Babikian, D. S.; Craig, R.; Palumbo, G.; and Palmer, G:

Measured and Calculated Spectral Radiation from

a Blunt Body Shock Layer in an Arc-Jet Wind

Tunnel. AIAA Paper 94-0086, Reno, Nev., 1994.

Babikian, D. S.; Gopaul, N. K. J. M.; and Park, C: Measurements and Analysis of Nitric Oxide Radiation

in an Arc-Jet Flow. J. Thermophys. and Heat

Transfer, vol. 8, no. 4, Oct.-Dec. 1994, pp. 737-743.

Babikian, D. S.; Park, C.; and Raiche, G. A.: Spectroscopic Determination of Enthalpy in an Arc-Jet

Wind Tunnel. Presented at 33rd AIAA Aerospace

Sciences Meeting and Exhibit, Reno, Nev., 1995.

Bamford, D. J.; O'Keefe, A.; Babikian, D. S.; Stewert,

D. A.; and Strawa, A. W.: Characterization of Arc

Jet Flows Using Laser-Induced Fluorescence.

AIAA Paper 94-0690, Reno, Nev., Jan. 1994.

Park, C.; and Babikian, D. S.: User's Manual for

NOZNT and NOXIT, Nozzle in n-Temperature

and Nozzle in One Temperature. NASA TN, in

review.

Park, C.; and Lee, S. H.: Validation of ThreeTemperature Nozzle Flow Code NOZ3T. AIAA

Paper 93-2862, Orlando, Fla., June 1993.

Keywords

Arc-jet wind tunnel, Nonequilibrium expanding flows,

Radiative heating of blunt body

27
Three-Dimensional (3-D) Disturbances Generated by Suction

Holes for Laminar Flow Control (LFC)

Investigator(s)

Daniel C. Reda, Ames Research Center,

Moffett Field, CA 94035-1000

Jonathan H. Watmuff, MCAT Institute,

Ames Research Center

Objectives of the study

The beneficial effects of 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. Flight tests have been

conducted recently using porous surfaces containing

about 109 laser drilled holes of 0.002 inch diameter.

The drag reduction obtained .by maintaining laminar

flow over a substantial portion of the wing surface

potentially offers considerable fuel savings. Suction, as

a means for laminar flow control, is being seriously

considered for production aircraft in the near future.

Even the most sophisticated engineering design

tools for predicting the transition location assume that

the suction is uniform. I_6 some cases there is evidence

to suggest that the discrepancy between the predicted

and observed transition location may be due to local

three-dimensional (3-D) disturbances that are generated by the discrete holes. It is known that a pair of

streamwise vortices are generated by a hole when the

suction is strong. Designers of porous surfaces use

Goldsmith's Criterion to minimize cross-stream interaction between these vortices. However nothing is

known about the streamwise interactions that are

likely to be even more important. The objective of this

project is to determine the characteristics of disturbances generated by suction holes, whether they decay

or amplify with streamwise distance, and whether

there are interactions between disturbances generated

by different holes, which are aligned, but displaced in

the streamwise direction.

Progress and results

A small-scale wind tunnel previously used for turbulent boundary layer studies has been modified for

experiments in laminar flow control. The facility

incorporates suction through interchangeable porous

test surfaces, which are used to stabilize the boundary

layer and delay transition to turbulent flow. The thin

porous test surfaces are supported by a baffled

plenum chamber box, which also acts to gather the

flow through the surface into tubes that are routed to a

high pressure fan. An elliptic leading edge is attached

to the assembly to establish a new laminar boundary

layer on the test plate. A slot is used to remove the test

section flow below the leading edge. The test section

was lengthened and fitted with a new ceiling. Substantial modifications were also made to the 3-D probe

traverse.

Transformation of the facility for laminar flow

studies has been accomplished with considerable success. The free-stream unsteadiness is 0.08 percent for a

unit Reynolds number Rex = 1.25 x 106 m -1 (i.e., a

nominal free-stream velocity of 18.5 m/s). Intermittent

bursting is observed at x = 1.8 m, i.e., Rex = 2.25 x 106,

which is very good for an open-return wind tunnel.

The layer thickness ranges from 2.5 mm (0.1 inch) to

4.8 rnm (0.2 inch) over the measurement range. The

conformance of the mean velocity profiles with Blasius

profiles is excellent; e.g., the experimental shape factors range from 2.54 to 2.75 compared to the Blasius

value of 2.59. The skin friction coefficient Cf estimated

from the velocity gradient at the wall follows the

Blasius Cf versus Rex distribution within the

experimental uncertainty.

Detailed studies have been made using isolated

holes to explore the underlying instability mechanisms. The suction is perturbed harmonically and data

are averaged on the basis of the phase of the disturbance. These studies were performed using centerline

pressure tap holes in the impervious plate, which has

been used to verify the acceptability of the base flow.

Experiments concerning suction hole disturbances

have consisted of the introduction of a harmonic disturbance at an isolated hole via a speaker attached to a

pressure tap line. The streamwise location of the hole

corresponds to Rex = 1 x 106, and the nondimensional

frequency F = 40 x 10 -6 corresponds to most amplified

modes at this Reynolds number. Conditions corresponding to strong suction and no suction have been

studied. The facility is totally automated under computer control and can be run continuously (24 hours/

day) for weeks at a time. Data are collected on a pointby-point basis and multiple probes have been implemented to reduce the experimental run time. An

unprecedentedly large quantity of data have been

acquired; e.g., two data sets have been obtained on

four grids totaling 79,560 data points each. The results

are examined using the software tools developed for

studying the results of numerical simulations on a

28
graphicsworkstation.In bothcases(i.e.,with and

without suction), 3-D contour surfaces in the vicinity

of the hole show highly 3-D Tollmein-Schlichting (TS)

waves that fan out away from the hole with streamwise distance. With suction, the perturbations on the

centerline are much stronger and decay less rapidly,

whereas the far field is similar to the case without

suction. Downstream the contour surfaces of the bowshaped TS waves develop spanwise irregularities,

which eventually form into clumps. The contours

remain smooth when suction is not applied. The spanwise clumping is evidence of a secondary instability

that could be associated with suction vortices. The

interaction between TS waves generated by two holes,

aligned, but displaced in the streamwise direction,

indicate that cancellation of TS waves is possible.

Significance of the results

Even without suction, the harmonic point source is

challenging for computational fluid dynamics (CFD);

e.g., direct numerical simulation (DNS) has been used

for streamwise growth. With suction, grid resources

are consumed by modeling the flow within the hole,

and this makes DNS even more expensive. Designers

of porous surfaces use Goldsmith's Criterion to minimize cross-stream interaction. However, nothing is

known about the streamwise interactions. Results

using two holes, aligned but displaced in the streamwise direction, indicate that partial TS wave cancellation is possible, depending on the hole spacing and

disturbance frequency. Using DNS for streamwise

interaction studies will be prohibitively expensive if

linear superposition cannot be used for the multiple

holes. The demonstration of TS wave cancellation from

multiple holes is an important result since it implies

that an optimal streamwise hole spacing could exist

for cancellation of TS waves. The optimum hole spacing would be a function of the flow speed (i.e., TS

wavelength).

Publications resulting from study

Watmuff, J. H.: Interaction Between Instabilities

Originating from Suction Holes. Presented at the

46th Annual Meeting of the American Physical

Society, Albuquerque, N. Mex., Nov. 1993.

Watmuff, J. H.: High-Speed Real-Time Processing of

Cross-Wire Data. Accepted for publication in

Experimental Thermal and Fluid Science Journal.

Keywords

Suction, TS waves, Instability

29
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

Objectives of the study

A sensitive capacitance transducer was successfully

developed and used to measure a thinning oil wedge

on a fiat-plate model in the High Reynolds Pilot

Channel.

Progress and results

The most significant results from this project are as

follows:

A. Demonstrated the ability to measure film

thickness in the micron range using a rugged flush

mounted transducer.

B. Developed and tested a means of providing

remotely controlled oil injection in the line configuration required by the oil wedge technique.

C. A "nonlinear" period of oil wedge thinning

was observed at the beginning of a test run using oil of

1000CS viscosity. The initial rapid thinning behavior

implies that significant pressure forces are present in

addition to the desired shear force. This occurs in an

excessively thick oil layer and violates conditions

required by various fringe imaging techniques that

examine fringe spacing only at the conclusion of a test

run. Skin friction values inferred from such "pressure

force" contaminated data, could, of course be significantly in error.

D. As a spinoff from the DDF research, a means

of detecting ice formation on aircraft and warning the

crew was developed. A U. S. patent application was

filed on April 26, 1994, entitled "Ice detector and deicing fluid effectiveness monitoring system"

Keywords

Liquid film thickness measurement

30
Effects of Atomic Oxygen and Nitrogen on Advanced

Thermal Protection Materials

Investigator(s)

Susan White, Ames Research Center,

Moffett Field, CA 94035-1000

Joan Pallix and Les Barnes, Thermosciences

Institute, Ames Research Center

Objectives of the study

To develop more effective and lighter weight

advanced thermal protection materials for spacecraft,

it is important to understand how these materials will

behave under atmospheric entry heating conditions.

One important component of reentry heating involves

heterogeneous atom recombination, which can account

for a significant fraction of the surface heating rates. In

order to predict the full envelope of surface heating

rates, atom recombination coefficients are required

over surface temperatures ranging from room temperature to ~1,800°C. Experiments performed in the

arc-jet facility at the Ames Research Center yield coefficients for surface temperatures in excess of 1,100°C.

In order to address the catalytic behavior of thermal

protection systems at lower surface temperatures, a

versatile laser based diffusion/flow reactor has been

developed in collaboration with Richard Copeland at

SRI International.

It is well established that diffusion reactor methods are well suited for temperature dependent studies

of atom recombination on surfaces of relatively low

catalytic activity. A number of diffusion reactor

designs have been used to study surface catalysis,

most of which use a translating catalytic probe positioned inside the reactor to monitor atom loss due to

wall recombination. These techniques have been limited to studies of simple first order surface reactions

involving H, O, or N atom recombination. The reactor

developed during this funding period is much more

versatile in that it applies laser-induced fluorescence

(LIF) to study the effects of atom/surface interactions

on various catalytic materials. The laser probe method

is non-intrusive and will not interfere with the flow

field or diffusion in the reactor. The technique is also

species selective so that reactant and product concentrations can be monitored directly in most cases of

interest to the spacecraft reentry problem. This will

allow studies of more complex reactions such as

N+O->NO (there are little data currently available on

this surface catalyzed reaction) or CO+O->CO2, which

is an important issue for the Mars entry problem. The

measurements can also be made very reliable, reproducible, and routine with the correct equipment and

expertise.

Progress and results

A schematic diagram of the reactor developed during

this funding period is shown in figure 1. The technique

involves generation of atoms in a microwave discharge. The atoms diffuse down a tube where they can

recombine on the walls, which are coated with the

catalytic material of interest under steady state conditions. The loss of atoms due to wall recombination is

monitored using fluorescence detection. The twophoton fluorescence was obtained by focusing

frequency doubled radiation from an excimer-pumped

dye laser through the center of the quartz side-arm.

Because this is a two-photon process, most of the

signal comes from the area near the focus of the

excitation laser beam and, therefore, the O-atom

concentration can be measured at various positions in

the diffusion reactor by either moving the reactor or

moving the focus of the laser beam and the detector. A

combination of the laser beam geometry and the

characteristics of the fluorescence detection system

determines the spatial resolution. LIF intensity (I) is

measured as a function of distance from the discharge

where the atoms are generated and it gives a measure

of the atom concentration gradient in the tube. Under

the proper experimental conditions, the atom

recombination coefficient can be determined from the

slope of the line generated from a plot of In(I) versus

X/R where X is the distance from the discharge and R

is the diffusion tube radius (fig. 2).

For temperature dependent measurements the

active section of the reactor is equipped with a tube

furnace, which can heat the system to 1,200°C. The

work carried out so far involves room temperature

detection of O atom recombination on a quartz catalyst. This simple system was chosen for the initial

measurements in order to determine the feasibility of

the detection methods and to validate the reactor

model used for data analysis. Many of the potential

sources of error in measuring atom recombination

coefficients by this method have been identified and

taken into account in these preliminary investigations.

These include scattered light, detector saturation,

sample surface cleanliness, reactor design, gas pressure and composition, and selectivity of the laser

probe. Through these detailed investigations of

experimental variables, an optimized experimental

31
_j

L)

r._

i,-

m

o

m

U.

(/)

cU

L

_tlPE

i_(/)

32
A

ee"

6Ov

(9

O

...1

4.8

3.6

2.4

1.2

0.0 ] 1, ! ,! !. I .N, I I

0 10 20 30 4O 50

DISTANCE/RADIUS

Figure 2. Log (signal intensity) versus the ratio of the distance from the discharge to the radius of the tube for atom loss data

obtained at 0.22, 0.41, and 0.67 Torr.

design was possible that will yield more accurate and

reliable reaction rate data.

Significance of the results

Through this work, we have established the feasibility

of using LIF for detection of atom loss in a diffusion

tube to measure surface catalytic activity on a routine

basis for all new thermal protection systems (TPS)

developed at Ames Research Center. The experimental

apparatus is versatile in that it allows fluorescence

detection to be used for measuring recombination

coefficients as well as for diffusion tube and microwave discharge diagnostics. The results have been

invaluable for establishing a design for an improved

and more reliable diffusion reactor and model for

surface catalysis studies in the thermal protection

materials program. Continuation of this program will

be supported by the NASA Access to Space Program.

Publications resulting from study

Pallix, J; and Copeland, R.: LIF Detection of O and

N Atom Recombination in a Diffusion Reactor.

Submitted to the J. Spacecraft and Rockets.

Kneirim, K; Pallix, J.; and Cagliostro, D.: Modeling

Considerations for Atom Recombination in a

Diffusion Tube. Submitted to the J. Spacecraft and

Rockets.

Copeland, R.; and Pallix. J.: Materials Testing Via O

and N Atom Detection. Summary Report for

Contract No. A40537D, SRI International, Menlo

Park, Calif., July 1994.

Copeland, R.; and Pallix. J.: Oxygen Atom Scattering

and Recombination Experiments. Summary

Report for Contract No. A28698D, SRI

International, Menlo Park, Calif., Aug. 1994.

Keywords

Catalysis, Atom recombination, Diffusion reactor

33
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

Center, 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 (Lamb, 1957; Rayleigh, 1894; Schuder and

Binder, 1959; Iberall, 1950; and Berg, 1965).

This research attempts to develop methods for

numerical compensation of pressure measurement

distortion induced by pneumatic tubing, which cannot

be mitigated in the instrumentation 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

Deconvolution algorithms to perform the compensation were developed and verified. 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.

The actual implementation is performed using a

"sliding window" deconvolution in which the Fourier

transform has been rewritten to be a recursive implementation. The "sliding window" transform takes the

nominal N-point discrete transform and reformulates

it to be recursive based on a starting or "seed" transform. After application of the Wiener filter to perform

the pressure compensation, the output time series is

implemented by recursively writing the inverse transform in much the same manner.

The compensation algorithms are depicted

schematically in figure 1. The recursive formulation

allows the code to be implemented efficiently in verynear real time with computational latencies always

less than one-half of the window time-length. The

algorithm was coded and implemented on a

TI-C0303 DSP processor. Laboratory experiments to

verify the algorithm capability were performed, and

sample results are presented in figure 2.

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 the "sliding window"

algorithm allows the filter to be implemented in real

time. The algorithm has already been applied to the

reconstruction of the sonic boom signature for the

SR-71 from highly attenuated pitot-static pressure

measurements.

References

Berg, H.; and Tijdeman, H.: Theoretical and Experimental Results for the Dynamic Response of

Pressure Measuring Systems. NLR Report F.238,

1965.

Iberall, A. S.: Attenuation of Oscillatory Pressures in

Instrument Lines. National Bureau of St_indards

Research Paper RP 2115, July 1950.

Lamb, J. P.: The Influence of Geometry Parameters

Upon Lag Error in Airborne Pressure

Measurement Systems. WADC TR 57-351, WrightPatterson AFB, Ohio, July 1957.

Mendel, Jerry M.: Optimal Seismic Deconvolution, An

Estimated Based Approach. The Academic Press,

New York, N.Y., 1983.

Rayleigh, Lord J.: The Theory of Sound. Second ed.,

Macmillian and Company, London, 1894.

34
Schuder, C. B.; and Binder, R. C.: The Response of

Pneumatic Transmission Lines to Step Inputs. J.

Basic Engineering, ASME Transactions, Dec. 1959.

Keywords

Digital signal processing, Deconvolution, Pressure

compensation

Select Window Size, N

I

PLk+N

Input

Pressure

PLI, PEa .... PLN

!

PL], PI2,1. • PLN (Input Time Series, Sampled

• 2 at Time Interval At)

i) Transform

PL[J(thn] (k+l) = d2/t Ndn[PL[j(Oml(k) +(PON*k - POk) At]

ii) Filter Compensation

v0c0)*

P00co) = Primo)

IIN((o)lt2

IV(o_)l2 +

IIP((o)ol2

ill) Inverse Transform

N-I N/2-1

= N At p=l

Repeat for each time frame

)0k+N/2

(Compensated Time

Series, Output

at Time Interval At)

Re[eL.l}

Figure 1. Schematic of compensation algorithm.

1899

Pressure1897

(Psf.)

1895

189',

1899

Pressure1897

(Psf.)

1895

1893

0.0

De-Convolved (Compensated)

" _ Input Estimate

Actual External Input

Pressure

"\ ?¢* ,".. /'/_

At t e nuat ed' (Measured) II_'

Pesponse

I I I I 1 _L J__l ._1__2

.04 .08 .12 .16 .20

Figure 2. Sample reconstructed pressure time history (real-time algorithm).

35

SECTION 2

ONGOING REPORTS

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

Objectives of the study

The objective of this study is to adapt and apply

the techniques of analytical electron microscopy

(AEM) to understanding fossilization processes in

siliceous thermal spring deposits. AEM is a general

term that describes a variety of high spatial

resolution analytical techniques, including high

resolution transmission electron microscopy

(HRTEM), electron diffraction (SAED), energydispersive x-ray microanalysis (EDX) and electron

energy loss spectroscopy (EELS). In properly

prepared samples, it is possible to perform

quantitative elemental analyses at the

10-20 nanometer (nm) level, to record structural

(electron diffraction) information from <10 nm

areas, and to image features of interest with

sub-nm resolution. With these new analytical tools,

we have been studying the processes by which

biological information is incorporated into the fossil

record of thermal springs. This is important because

thermal springs are regarded to be important

environments for early evolution of life on Earth and

possibly also on Mars. Although there are good

reasons to suspect that the earliest organisms lived at

high temperatures, we have not yet discovered

thermal spring deposits in ancient rock sequences on

Earth. Progress in finding such deposits has been

thwarted by a general lack of information about the

sedimentology and fossilization processes in modem

thermal springs. Thermal spring deposits have also

been given a high priority in exploring for evidence

of an ancient biosphere on Mars, and they figure

prominently as targets for upcoming surface and

sample return missions. A major goal of the

research is to develop criteria for the recognition

of ancient thermal spring microbiotas on the early

Earth and Mars.

Progress and results

Based on the early fossil record on Earth, the best

preservation of microorganisms occurs when they are

rapidly entombed by fine-grained stable minerals

prior to their degradation. The most favorable medium

for long-term preservation is fine-grained silica that

resists chemical breakdown and is able to retain biological information over long periods of geologic time.

Siliceous thermal springs are favored for study

because extremely high microbial productivity often

occurs in combination with high rates of silica precipitation. Not surprisingly, such deposits are often richly

fossiliferous because numerous microorganisms

become entombed by silica as spring waters rise to the

surface and cool. Understanding how post-burial processes, broadly referred to as diagenesis, affects the

fossil information in siliceous sediments is basic to

interpreting their paleontology. Thus, much of our

research to date has focused on studies of diagenesis

and its effect on paleontology in silica-rich sediments

(cherts) similar to those found in the early record on

Earth.

In obtaining samples for study, we extensively

sampled thermal spring outflows at several localities

in Yellowstone National Park. Samples were initially

studied using standard petrographic and light microscopic techniques. We also prepared biological

samples by critical point drying methods for scanning

electron microscopy (SEM). AEM provides the opportunity to observe the ultrastructure of the microfossils

and map associated elemental distributions at high

spatial resolution. Microfossils observed in thin sections were subsampled by microdrilling and prepared

for AEM by ion milling. Unfortunately, the work has

progressed slower than planned because of long

delays in the procurement of an ion milling device,

critical for AEM sample preparation. Nevertheless, the

work to date has provided important insights into the

nature and processes of fossil preservation. We have

developed an impressive data base of new information

about fossilization processes in thermal springs, combining observations from light microscopy and SEM

with more focused observations using AEM. This

work is being organized into a compendium of microchemical microstructural, and paleontological

observations that will be used to interpret ancient

thermal spring deposits. For example, we just

completed an initial description of 350-million-yearold thermal spring deposits we discovered last

summer in NE Queensland, Australia. Next year we

plan to extend our search for ancient deposits to

Archean-aged (-3.5 billion years old) rock sequences

in Australia and will apply similar techniques to

39

_PAGI_.3 _ INTENTiON_Ly BLA.N_,
search for high temperature microorganisms to some

of the oldest rocks on Earth.

Publications resulting from study

Farmer, J. D.; and Des Marais, D. J.: Biological Versus

Inorganic Processes in Stromatolite Morphogenesis: Observations from Mineralizing Systems. In

Microbial Mats: Structure, Development and

Environmental Significance, L. J. Stal and

P. Caumette, eds., NATO ASI Series in Ecological

Sciences, Springer Verlag, 1994.

Farmer, J. D.; Des Marais, D. J.; Blake, D. F.; Walter,

M. R,; andHinman, N. W.: Paleobiology,

Mineralogy, and Geochemistry of Modern and

Ancient Thermal Spring Deposits and Their

Recognition on Early Earth and Mars. Fifth

Symposium on Chemical Evolution and the Origin

of Life, and Workshop on Mars Exobiology

Science Strategy, NASA Ames Research Center,

April 25-29, 1994.

Farmer, J. D.; and Des Marais, D. J.: Exopaleontology

and the Search for a Fossil Record on Mars. Lunar

Planetary Science, vol. 25, 1994, pp. 367-368.

Roles of Biology, Sedimentation, and Diagenesis in

Determining Stromatolite Microstructure. Harvard

Stromatolite Workshop, Botanical Museum,

Harvard University, Cambridge, Mass.,

Oct. 18-21, 1993.

Farmer, Jack D.: High Resolution Transmission

Electron Microscopy. Sponsored by the

Mineralogical Soc. of America, Miami, Ohio, Oct.

1992.

NASA Ames Space Science Division, Contractor

Recognition Award to Jack D. Farmer, 1994.

NASA Ames Space Science Division, Contractor

Recognition Award to Jack D. Farmer, 1993.

Keywords

Mars exobiology, Hot spring sinter, Silification

4O
Isotopic Analysis of Meteoritic Organosulfur and

Organophosphorous Compounds

Investigator(s)

Sherwood Chang, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

George Cooper, National Research Council

Postdoctoral Associate, Ames Research Center

Objectives of the study

The hypothesis of the proposed research is that the

organic sulfonic and phosphonic acids newly

discovered in Murchison meteorite are of interstellar

origin. To test this hypothesis, we measure the sulfur

(36S/33S/32S), carbo n (13C/12C) and hydrogen

(D/H) isotope ratios as appropriate for individual

(methyl, ethyl, isopropyl, and n-propyl) sulfonic and

phosphonic acids extracted from Murchison meteorite.

The observation of isotopic ratios that are anomalous

with respect to bulk meteoritic or other known solar

system values will be indicative of presolar origins.

The observation of such anomalies would demonstrate

that all the main elements used by life on Earth originated, at least in part, in the interstellar cloud of gas

and dust that spawned the solar system. These analyses are especially interesting since no individual

organic compounds have ever been studied for their

sulfur isotopic compositions, let alone in combination

with their C- and H-isotopc compositions.

Progress and results

In the first year of funding, an ion chromatograph was

purchased and placed in routine operation for isolation and purification of target compounds. High vacuum sample analysis lines were constructed to

convert isolated compounds into gaseous species

suitable for analysis by stable isotope ratio mass

spectrometry.

We have demonstrated an ion chromatography

protocol for a sample-efficient separation, first of bulk

organic phosphonates from sulfonates, and then of

individual sulfonates from each other with complete

or near complete baseline resolution. This separation

allows isotopic measurements for C, H, and S on

individual compounds. These analytical procedures

were also shown not to perturb the natural isotope

ratio of carbon. A preliminary set of analyses of

individual sulfonic acids (methyl, ethyl, isoprbpyl, and

n-propyl) has been completed.

Significance of the results

Our first set of results show carbon isotope ratios distinct from terrestrial, but well within the range of other

meteoritic organic compounds. Apparently, the carbon

in these sulfonic acids is not anomalous. A monotonic

decrease in the 13C/12C ratio with increasing carbon

number, however, suggests a synthesis of larger compounds by stepwise reaction from one-carbon precursors. This result agrees with earlier results we obtained

with meteoritic carboxylic acids.

Apparently, distinctively anomalous isotope ratios

must be sought in the hydrogen and sulfur in the sulfonic acids and, presumably, in the hydrogen of the

phosphonic acids. We are poised to accomplish these

additional measurements in the second year of

research.

Keywords

Meteorites, Organic compounds, Stable isotopes

41
Robust Nonlinear Control and Guidance System Design

Methods

Investigator(s)

Victor H. L. Cheng, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Chima E. Njaka, Ames Research Center

P. K. Menon, Santa Clara University,

Santa Clara, CA 95053

Objectives of the study

The overall objective of this research is to investigate

methods for designing nonlinear control systems that

can tolerate substantial variations in the plant parameters without becoming unstable or suffering significant

degradation in performance, for the automation of aircraft guidance and control. The detailed objectives are:

• To understand the source of performance

degradation due to uncertainties in a realistic aircraft

model.

• To develop design methods for controllers that

can provide robust performance under some bounded

nonlinear system uncertainties.

• To evaluate the design techniques to verify the

improvement in robustness over existing controller

designs.

Progress and results

Two approaches were proposed for the investigation

of design methodologies for robust nonlinear controllers for automation of aircraft guidance and control

systems. A helicopter control problem has been

selected as the application to evaluate these

approaches because of the criticality of robust performance and stability of helicopters in ground-hugging

nap-of-the-Earth (NOE) flight. During the first year of

this two-year effort, a baseline controller for attitude

control of the UH-60A Black Hawk Helicopter has

been designed based on the GenHel simulation model.

This baseline controller involves a nonlinear inverse of

the helicopter's rotational dynamics, which is modeled

based on linearization of the force and moment aerodynamics over the flight envelope of interest. The

nonlinear-inverse controller constitutes part of the

robust controller to be designed with the first

approach. Preliminary analysis of this nonlinearinverse controller is complete. Work has already

started on the second approach, for which a force/

moment generation software model has been

developed to serve as an integral part of a robust nonlinear controller.

Significance of the results

Analysis of the nonlinear-inverse controller already

suggests that, because of the approximation introduced by linearization of the force and moment aerodynamics, the overall closed-loop system does not

behave entirely like a linear time-variant system, as it

should. Hence model uncertainty is inherent in this

baseline closed-loop system. This system would serve

as a good starting point to evaluate the full robust controller, which, if successful, should provide improved

performance under such model uncertainty.

Publications resulting from study

Njaka, C. E.; Menon, P. K.; and Cheng, V. H. L.:

Towards an Advanced Nonlinear Rotorcraft Flight

Control System Design. Paper presented at the

13th AIAA/IEEE Digital Avionics Systems

Conference, Phoenix, Ariz., Oct. 30--Nov. 3, 1994.

Keywords

Guidance and control, Nonlinear controller, Robust

controller

42
Study of Efficiency Gain and Emission Reduction in a Pulse

Combustor Design for Jet Engines

Investigator(s)

G. S. Deiwert, Ames Research Center,

Moffett Field, CA 94305-1000

J-L. Cambier and Henry G. Adelman,

Thermosciences Institute, Palo Alto, CA 94303

Objectives of the study

To study the effects of pulsed combustion on both

combustion efficiency and NOx formation for gas turbines. The first objectives are to develop a computational model of the pulse combustor and to analyse the

fundamental processes of pulsed combustion and their

dependence on various characteristic time scales. Once

this is established, the study will focus on the tuning of

the combustor parameters for minimization of NOx

production and/or maximization of efficiency.

Progress and results

A one-dimensional version of a combustion code has

been used for the simulations of the pulsed combustor.

The code is presently being modified for more generalized boundary conditions. A reduced chemical scheme

of propane-air combustion has been also devised, such

that the kinetics of NOx formation can be still modeled, while the unimportant details of the combustion

mechanism are ignored, leading to dramatic savings in

computational cost. The code has been implemented

also on a Silicon Graphics, Inc. (SGI) workstation, with

a graphics interface for real-time visualization of the

flow field.

A generic pulse combustor operating at atmospheric pressure is presently being studied. The first

group of simulations compared the steady flow results

with those where acoustic waves are artificially generated. It was verified that the acoustic waves could

propagate accurately with the second order scheme

used. A second group of simulations was then performed, where the pulsations were forced by imposing

a sinusoidal variation of the global combustion rate.

This is intended to model the periodic acceleration and

deceleration of a turbulent flame within the combustor

chamber. It was found that the pulsations could be

amplified for certain frequencies, with an apparent

resonance around 200 Hz. The oscillations were also

found to go through sequences of mode doubling as

the frequency was decreased. It was found also that,

by abruptly stopping the forcing mechanism, the pulsations were seen to rapidly disappear, even for the

43

resonant case, suggesting the existence of a strong

damping mechanism. This may be associated with the

geometry of the combustor, and it will be systematically investigated soon. The NOx production was also

seen to oscillate, as can be seen, for example, in

figure 1, but with only small effects on the cycleaveraged values. The oscillations were also observed

to be strongly dependent on the nature of the

boundary condition imposed near the combustor

entrance. The presence of a flapper valve, for example,

by limiting the rate of fuel/air injection into the

burner, leads to much smaller amplitudes of pressure

and velocity oscillations.

Significance of the results

The current preliminary results indicate that, with

appropriate conditions, strong pulsations can be generated in the combustor. The influence of the type of

boundary conditions is very important and will be further studied. The code will be further developed for

more complex configurations (multiple injection ports,

recirculations). It is clear that the fundamental physics

300

250

200

150

100

12

o s

x

4

0

0.00 0.05 0.10 0.15

0.00

I I I

0.05 0.10 0.15

time (sec)

Figure I. Velocity and NOx fIuctuations (at end of pipe), for

the case of forced pulsations at 50 Hz. The dips in NOx are

in phase with the velocity peaks in the pipe.
of the pulse combustion can be quite complex, and

systematic parametric analyses must be performed

with great care.

Keywords

Propulsion, Detonation

44
Biotechnological Applications of Reuseable Surface

Insulation

Investigator(s)

Howard E. Goldstein and Daniel B. Leiser,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The objective of this study is to modify the insulation

used on the Space Shuttle to produce optimized functionally gradient ceramics for use in animal implantation experiments by W. Casey Fox of BioMedical

Enterprises, Inc., San Antonio, Texas, and Thomas B.

Aufdemorte of the University of Texas, Austin, Texas.

The material properties that are desired in this system

are a compressive strength of 5 to 50 megaPascals

(MPa), and a variable pore size of 50 to 500 microns (g)

that transitions to a pore size of 0.1 to 5 g at the soft

tissue interface. The processing methods for the materials will be developed and the chemistry studied.

Progress and results

W. Casey Fox and Thomas B. Aufdemorte have successfully implanted off-the-shelf reuseable surface

insulations (RSI) materials into monkeys. This work

has shown that RSI bone implants can work and they

are very biocompatible. However, little bone ingrowth

was observed in the "initial" materials, and the material properties of the RSI ceramic fiber system needed

improvement to be successful in a wide variety of

applications. One of the properties needing modification was the pore size of the material, and therefore, a

determination of the appropriate size required was

needed. As a result, samples of different RSI with three

sizes of holes (-160g, ~240g, and -375g) were

prepared for the next animal implant experiment of

Aufdemorte and Fox to determine if bone ingrowth is

faster in one size hole versus another or if it is inhibited in any hole. Several modifications of standard RSI

have also been evaluated in an effort to provide an

improved bone implant material. These modifications

include 1) using different composition RSI (i.e., fibrous

refractory composite insulation (FRCI)-40 and alumina

enhanced thermal barrier (AETB)-40) as the insulation

precursor, 2) sintering.the insulation at higher temperatures (i.e., 2,600°F) for extended periods of time, and

3) using different pretreatments of the insulation. Thus

far these attempts have been unsuccessful as the pore

size was not significantly modified from the off-theshelf material. Another modification of the material

produced by using inert fillers in the insulation during

processing was also prepared. Preliminary examination of this material indicates that some modification

of the pore size has occurred, but only the animal

implantation experiments under way will determine

its viability.

Significance of the results

Hundreds of thousands of bone implants have been

performed using less than ideal metal and organic

materials. In many cases the implants have to be

replaced every few years. The ultimate result of this

research project might be to produce implants that are

as viable as the natural bone. The payoff in terms of

ameliorating human suffering is potentially enormous.

Keywords

Bone implant, Reuseable surface Insulation,

Biocompatibility

45
A Long-Duration Test Flight of a Super-Pressure Balloon as a

Platform for Mars Exploration

Investigator(s)

Robert M. Haberle, G. Scott Hubbard,

Lawrence G. Lemke, and Geoffrey A. Briggs,

Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

James Cantrell, Utah State University,

Logan, UT 84322-4140

Objectives of the study

Demonstrate that a super-pressure balloon made from

Biaxial Nylon 6 can survive for at least one year in the

Earth's stratosphere at 120,000 feet, where the pressure

and temperature conditions are similar to those

expected on Mars.

Progress and results

Prior to committing our DDF funds, there were

numerous attempts to launch a nylon super-pressure

balloon by the Winzen Corporation (the manufacturer). None of these launches were completely successful. A grant was let to the Space Dynamics Lab

(SDL) at Utah State University to study the problem

and design a flight test program that would lead to the

achievement of our objective. SDL recommended a

design change (removal of the center load line) and a

series of flight tests that would begin with less ambitious objectives. For the first flight, the objectives were

to (1) reach the assigned altitude, (2) pressurize, and

(3) survive one day/night transition. This launch

occurred on August 30, 1994, and two of the three

objectives were met. After inflation, the balloon's cutdown system fired prematurely, separating the payload from the balloon. As a result the balloon ascended

to a much higher altitude than planned and ultimately

burst. Thus, the third objective was not achieved.

Significance of the results

Visual tracking of the balloon showed that the new

design is viable since the balloon reached its design

altitude without distortion or twisting (as was the case

with the old design). It also showed that the balloon

successfully pressurized, and that it ascended at least

20,000 feet beyond its design altitude. This success

indicates that the super-pressure margins for this

material are much greater than theoretically predicted.

Publications resulting from study

James Cantrell is preparing a final report.

Keywords

Mars, Super-pressure balloon, Biaxial Nylon 6

46
Intervertebral Disc and Back Pain Studies using Spinal

Traction and Compression during Magnetic Resonance

Imaging

Investigator(s)

Alan R. Hargens, Ames Research Center,

Moffett Field, CA 94035-1000

Gita Murthy and Donald E. Watenpaugh,

University of California at San Diego,

Ames Research Center

Jorma Styf, Ames Research Center

Karen J. Hutchinson, University of California at

San Diego, Ames Research Center

Douglas F. Schwandt, Bionetics, Inc.,

Ames Research Center

Other personnel involved

Richard Ballard, University of California at

San Diego, Ames Research Center

Klaus Fechner, V.A. Medical Center,

Palo Alto, CA 94304-1200

Wenonah Vercoutere and Sue Bowley,

Ames Research Center

Objectives of the study

The objectives of the first phase of this research were

to study intervertebral disc height and other potentially pain-related variables during simulated microgravity. Astronauts experience height increases of four

to seven cm in microgravity. Stretching of nervous,

muscular, and ligamentous tissues may be responsible

for the back pain associated with existence in microgravity. Axial compression of the spine makes six deg

head-down tilt (HDT) an unsuitable model for spinal

acclimation to microgravity. However, this axial compression may be counteracted by balanced traction

consisting of 10 percent body weight applied to

the legs.

Progress and results

Six healthy male subjects underwent three days each

of six deg HDT with balanced traction and horizontal

bed rest (HBR), with a two week recovery period

between treatments. Total body and spine length,

ultrasonographic lumbar disc height, back pain, erector spinae intramuscular pressure, peripheral nerve

conduction, and maximal ankle joint torque were measured before, during, and after each treatment. Total

body and spine (processes of vertebrae L5 - C7)

lengths increased significantly more during HDT with

balanced traction (22 + 8 mm and 25 + 8 mm, respec -

tively) than during HBR (16 + 4 mm and 14 + 9 mm,

respectively). Back and leg pain were significantly

.greater during HDT with balanced traction than during HBR. The distance between the lower endplate of

L4 and the upper endplate of $1, as measured by ultrasonography, increased significantly in both treatments

to the same degree (2.9 + 1.9 mm, HDT with balanced

traction; 3.3 + 1.5 mm, HBR). Back intramuscular pressure, leg nerve conduction velocity, and maximal

ankle joint torque were unaltered with both models.

We have also completed design of the spinal

compression harness to be used in the second phase of

this study.

Significance of the results

Although neither bed rest treatment increased height

to the magnitude observed in microgravity, HDT with

balanced traction may be a better model for simulating

the body lengthening and back pain experienced in

microgravity. Results suggest that microgravityinduced back pain may result from localized effects of

loss of spinal curvature; intramuscular pressure elevation and nerve stretching/compression are probably

not involved.

The compression harness will allow us to quantify

relationships between spinal loading and disc physiology and morphology in the second phase of this project. In the future, the harness will be used clinically to

load the spines of recumbent patients during magnetic

resonance imaging for diagnosis of back problems.

Publications resulting from study

Styf, J. R.; K/ilebo, P.; and Hargens, A. R.: Lumbar

Intervertebral Disc Heights as Measured by

Sonography. Aviation, Space, and Environmental

Medicine, vol. 65, no. 5, 1994, p. A12.

Ballard, R. E.; Styf, J. R.; Watenpaugh, D. E.;

Fechner, K.; Haruna, Y.; Kahan, N. J.; and

Hargens, A. R.: Head-Down Tilt with Balanced

Traction as a Model for Simulating Spinal

Acclimation to Microgravity. Presented at the

American Society for Gravitational and Space

Biology Meeting, San Francisco, Calif., Oct. 19-22,

1994.

47
Styf,J.R.;Fechner,K.;Ballard,R.E.;Watenpaugh,

D.E.;Kahan,N. J.;andHargens, A. R.: Height

Increase, Neuromuscular Function and Back Pain

During 6 ° Head-Down Tilt with Traction. Aviat.

Space Environ. Med. In preparation.

Haruna, Y.; Styf, J. R.; Kahan, N.; and Hargens, A. R.:

Hoffmann-Reflex is Delayed During 6 ° HeadDown Tilt with Balanced Traction. In preparation.

Keywords

Microgravity, Ultrasonography, Back pain

48
Turbulent Boundary Layer Measurements on Transport

Wing Wind Tunnel Models

Investigator(s)

Dennis A. Johnson, Ames Research Center,

Moffett Field, CA 94035-1000

Jeffrey D. Brown, Eloret Institute

Sunnyvale, CA 94087

Objectives of the study

The objective is to evaluate candidate laser Doppler

velocimeter (LDV) approaches for transport wing

boundary-layer measurements.

Progress and results

Measurements of both the streamwise and the crossflow velocity comp6nents are needed to define the viscous boundary layers on transport wing wind tunnel

models. Moreover, these measurements must be made

very close to the surface of the wind tunnel model

since the boundary layers are relatively thin. The

extreme gradients in velocity within the boundary

layer also place severe demands on spatial resolution.

The requirements are further complicated by the need

to measure separated flows.

In the current research, LDV approaches that provide better spatial resolution, greater sensitivity to the

cross-flow velocity component, and less susceptibility

to surface light scattering than previous approaches

are being evaluated.

Laser light scattered from the surface of the wing

represents the most formidable problem. This scattered light results in additive noise that can

overwhelm the weak signals produced by the scattering of laser light from small submicron particles in the

airstream. (In LDV, local instantaneous airflow velocities are deduced from the Doppler shift of laser light

scattered from airborne particles.)

Through laboratory studies, as part of this DDF

project, it has been confirmed that the amount of laser

light scattered from the surface of the model can be

reduced dramatically by placing inserts that are optically smooth on the wind tunnel model. Several types

of insert materials have been examined. One of these is

replicated nickel, for which the root mean square (rms)

roughnesses can be as small as several hundred

angstroms.

It has also been determined that substantial

improvements in near-surface measurement performance result as the laser beams are brought into a

tighter focus at the point of velocity measurement.

The next step in this research is to perform wind

tunnel studies that more accurately simulate the

conditions observed in wing testing.

Significance of the results

The laboratory results obtained so far give reason for

optimism, but the determination of actual measurement capabilities awaits wind tunnel tests to be performed soon.

Keywords

Boundary layers, Wings, Laser Doppler velocimetry

49
Flight Measured Wall Pressure Fluctuations Beneath Swept

Shock/Boundary Layer Interactions

Investigator(s)

Steven A. Johnson,

Dryden Flight Research Center,

Edwards, CA 93523-0273

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.

Obtaining these types of measurements is critical

to the development of advanced flight systems such as

the high-speed civil transport (HSCT) and other highspeed flight vehicles. Fluctuating pressure loads are

especially significant in that they can occur in conjunction with high aerothermal loads, and they can

threaten the structural integrity of flight vehicles.

The shock wave/boundary layer interaction is

generated by an equilibrium, flat plate turbulent

boundary layer interacting with a swept, planar

oblique shock wave. The shock wave is generated by

an "upright," sharp-leading-edged fin at angle of

attack. A schematic of the arrangement is shown in

figure 1. Also shown schematically are the fluctuating

pressure measurement locations to be used in the

experiment. Transducer ports are provided in the fiat

plate at 2 deg angular separations from 15 deg to

65 deg with respect to the free-stream direction. The

fiat plate/fin apparatus will be attached to an existing

"flight test fixture" and mated to the underside of an

F-15B aircraft. The flight test fixture is a specially modified pylon that is mounted vertically on the lower centerline of the F-15B. The F-15B, capable of speeds up to

Mach 2.0, will serve as the carrier aircraft for the

experiment.

of

pressure transducers

Figure 1. Model schematic showing transducer locations.

50
Thetest cases are chosen to span a wide range of

interaction strength. Previous investigators have found

that important features of swept shock-wave/

boundary layer interactions (SWBLIs) scale with the

strength of the inviscid shock wave, which can be

represented by either the Mach number normal to it or

the pressure rise across it. As a result, various fin

angles (shock strengths) will be investigated at a freestream Mach number of 2.0.

Much has been accomplished since funding was

awarded. All flight hardware has been designed and

fabricated. All instrumentation required for the acquisition of the unsteady pressures has been developed

and fabricated. A stand-alone, on-board data acquisition system has been developed that will reside within

the flight test fixture and will acquire the high sample

rate (100 kHz) pressure data.

In fiscal year 1995, a complete checkout of the

integrated system is planned--flight hardware, power

supplies, signal conditioning, and data acquisition.

After the systems operation is successfully demonstrated, a series of five high-speed flights will occur

using the NASA F-15B as the carrier aircraft.

Keywords

Unsteady pressures, Shock/boundary layer

interactions, Flight research

51
Practical Evaluation of a New Method to Reduce Helicopter

Rotor Hub Loads

Investigator(s)

Sesi Kottapalli, Ames Research Center,

Moffett Field, CA 94035-1000

Other personnel involved

Judah Milgram and Inderjit Chopra, University of

Maryland, College Park, MD 20742

Objectives of the study

The objective of this study was to evaluate a new passive device to reduce helicopter rotor hub loads. This

device is called the dynamically tuned blade 'pitch link.

Progress and results

The research reported here, an outgrowth of the work

reported last year, was performed using the analytical

rotorcraft code UMARC (University of Maryland

Advanced Rotorcraft Code). This finite element code

allows for a more sophisticated modeling of a blade

configuration under the effect of additional, parametric torsional damping.

Under this grant a modified version of UMARC

was created in which it is possible to vary the pitch

link damping instead of the blade modal torsional

damping that had been previously considered using

an earlier, completely different code. In the code that

was used earlier, there was no provision to model

pitch link damping as a valid parameter. Including

pitch link damping instead of the modal torsional

damping results in a more practical evaluation since

pitch links (with no damping) are an integral part of

current production helicopters. Finally, pitch link stiffness has also been included as a parameter and the

phrase "dynamically tuned blade pitch link" has been

coined to describe the resulting complete concept.

The dynamically tuned blade pitch link is a device

in which a rotor blade pitch link (also commonly

referred to as a pushrod) is replaced by a spring/

damper element. A sample study has been conducted

using an articulated rotor blade, the S-76 blade. To

summarize, it was found after extensive study that

pushrod damping in combination with reduced

pushrod stiffness results in significant reductions in

4/rev fixed system hub loads. In this context, figure 1

shows that the longitudinal inplane shear was reduced

by 25 percent, the roll moment by approximately

,02 f

I .01

0

Torsional frequency= 4/Rev

/

(a) Longitudinal inplane shear

.02 ! @_'_"-----

.01 -

0 (b) Lateral inplane shear

iT_

> .010

.oos

I

0

0

Zero pushrod damping

Cp = 2. (nondimensional)

Cp=3.

!:°311:

o-

_ .0010 .[_ .01Xl5

m 0

(d) Roll moment

(e) Pitch moment

(c) Vertical shear (f) Yaw moment

_ .OOtO I

.0005

-0

:_ 0 I, , = , ,

t a i i J _

10 20 30 0 10 20 30

PushrodStiffness Kp PushrodStiffnesa Kp

(nondimenslonal) (nondimensional)

Figure 1. Variations infixed system hub loads due to parametric changes in pushrod stiffness and damping; advance

ratio = 0.38, thrust coefficient divided by solidity = 0.080, shaft angle = 5 deg. Pushrod stiffness and damping nondimensionalized by a reference mass, rotor speed, and blade radius.

52
20percent, and the pitch moment by 25 percent. The

lateral inplane and vertical shears stayed the same. At

the same time, the 1/rev pushrod loads (not shown

here) increased by about 50 percent. The design of a

dynamically tuned blade pitch link may involve the

redesign of a production pushrod in order to accommodate the required stiffness/damping, and any additional fatigue considerations arising from the increased

1/rev loads can be included in this redesign phase.

The present reductions in hub loads signify that the

dynamically tuned blade pitch link is a promising

concept.

The next phase in this study in 1995 involves evaluating this concept for a tilt rotor configuration.

Publications resulting from study

Milgram, Judah; Chopra, Inderjit; and Kottapalli, Sesi:

Dynamically Tuned Blade Pitch Links for Vibration Reduction. Presented at the 50th Annual

Forum of the American Helicopter Society,

Washington, D.C., May 1994.

Keywords

Rotorcraft, Vibration reduction, Pushrods

53
Computational Fluid Dynamics (CFD) Simulation of Left

Ventricular Assist Device (LVAD)

Investigator(s)

Dochan Kwak, Ames Research Center,

Moffett Field, CA 94035-1000

Cetin Kiris, MCAT Institute,

Ames Research Center

Objectives of the study

Develop and apply computational fluid dynamics

(CFD) tools to simulate steady and unsteady flows

within artificial heart assist devices. This research is

designed to provide a tool that can be used to investigate the flow of blood through a ventricular assist

device. This unique insight into the internal fluid

structures will lead to improved artificial devices

capable of sustaining human life.

Progress and results

In 1989, the NASA Johnson Space Center (JSC) began a

joint project with the DeBakey Heart Center of the

Baylor College of Medicine (BCOM) in Houston,

Texas, to develop a new implantable left ventricular

assist device (LVAD) prototype system. This LVAD is

based on a fast rotating axial pump requiring a minimum number of moving parts. To make it implantable, the device has been made as small as possible,

requiring a very high rotational speed. The flow

through the baseline design of the LVAD impeller was

numerically simulated by solving the incompressible

Navier-Stokes equations in a steadily rotating frame of

reference. The pseudocompressibility approach and

zonal multiblock grids were used in these component

analyses. A parametric study was performed to

optimize the impeller blade shape and the tip clearance. The ideas from rocket propulsion and medical

science were combined to help develop a new

implantable LVAD. Using the new computational

technology, the researchers in collaboration with the

JSC engineering team are investigating new design

possibilities by combining a rocket engine inducer

with an axial blood pump impeller. The BCOM is currently performing clinical hemolysis testing and animal implantation. The new design is showing a

remarkable improvement in performance over earlier

blood pump designs.

Significance of the results

The goal of this research was to develop computational tools that could be used by the designers of

mechanical heart assist devices, such as the JSC/

BCOM LVAD. This computational tool now affords

designers with a view of the complicated fluid

dynamic processes inside their devices. Because of the

nature of the devices, this detailed information cannot

be obtained experimentally. The detailed computational look at the fluid flow is very important to the

designers; high levels of turbulence can damage the

red blood cells, and regions of recirculating flow can

lead to blood clots. Thus the ability to predict these

phenomena have greatly helped the designers.

In July 1991, the Institute of Medicine estimated

that approximately 25,000 to 60,000 patients per year

in North America could benefit from an efficient

LVAD. Thus improved designs made possible because

of the current work could have a significant impact on

human health.

Keywords

Computational fluid dynamics, Incompressible flow,

Left ventricular assist device (LVAD)

54
A Study of Atmospheric Sampling by Supersonic Aircraft

Investigator(s)

Stephen R. Langhoff and Henry G. Adelman,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The use of supersonic aircraft with long-range and

high-altitude capabilities has been proposed to obtain

atmospheric samples to study the depletion of the

ozone layer over the polar regions. However, there is a

possibility of changes in the composition of samples

that have passed through the shock waves generated

by the aircraft at supersonic speeds. At these elevated

temperatures and pressures, the samples may undergo

chemical reactions that would alter their composition

dramatically, giving incorrect sampling results. The

extent of chemical changes that might occur during

supersonic sampling will depend on the speed and

altitude of the aircraft and the temperature and pressure history of the sample.

Progress and results

Reacting flow models are being used to determine

possible sample chemistry changes due to the increase

in temperature and pressure across shock waves. The

sample temperature and pressure history are determined as functions of aircraft speed and altitude. The

flow environment is calculated along a streamline that

begins in the undisturbed flow and passes through the

shocks before entering the probe. Speeds up to Mach 3

and altitudes to 20 km are being covered by the study.

The development of the necessary reaction

mechanisms and thermochemical data base to

describe shock heating of the samples is in progress.

While atmospheric modelers are concerned with

limited temperature (217 K-250 K) and pressure

(0.03-0.14 arm) ranges, the air samples could be

subjected to temperatures up to 600 K and pressures

35 times higher than ambient conditions. Computational chemistry methods have been used to predict

thermodynamic properties of important sample

species not found in current data bases including heats

of formation, specific heats, enthalpy, and entropy as

functions of temperatures up to 600 K. Reaction

mechanisms and thermodynamic data relevant to

sample conditions are being added to the flow simulations. Conditions after normal or oblique shock are

input to the model, and parametric studies of sample

changes are performed as functions of aircraft speed

and altitude. The species of interest in atmospheric

sampling include ozone (03), oxides of nitrogen (NO,

NO2, NO3, N205) and chlorine compounds (C1, C10,

C10 2, C120 2, C1NO3). Shock heating can convert the

species being measured to other compounds. For

example, if nitrogen dioxide were to be sampled, its

concentration might be significantly increased from

the ambient amount by the following reactions that

can occur after shock heating:

NO + 03 --> NO2 + 02

C1NO3 --> CIO + NO 2

Preliminary results show that the chemical

integrity of the sample depends on the aircraft speed

and the species. For example, at Mach 2, the above

reactions do not begin for approximately 10 milliseconds. At Mach 3, however, the sample begins to

change composition in about 1 microsecond. The

amount of change that can be tolerated depends on the

species being measured and the time required to hold

the sample. The effects of shock heating are currently

being investigated for other reactions and species. If

the sample heating is too severe to permit chemical

integrity, then the possibility of sampling from the

cold leeward side of a fiat plate inclined to the flow

will be examined.

Significance of the results

Although there has been speculation about the effects

of sampling from supersonic aircraft, no previous

studies of this phenomenon have been made. This

work combines the unique capabilities of the

Computational Chemistry Branch at the Ames

Research Center to predict species thermodynamic

properties and reaction rates with reacting flow modeling to examine this important issue.

Keywords

Atmospheric sampling, Ozone depletion, Supersonic

flight, Stratospheric chemistry

55
Formation of Organic Matter from Carbon Dissolved in

Minerals

Investigator(s)

Narcinda Lemer, Ames Research Center,

Moffett Field, CA 94035-1000

Friedemann Freund, SETI Institute,

Ames Research Center

Before life could start on the early Earth some 3.2 billion years ago or earlier, there must have existed a

large reservoir of abiotically formed organic matter.

The first organisms that evolved must have used these

pre-existing organic molecules to build their bodies

and metabolic functions. To understand how this happened is a BIG question. Unfortunately, in spite of

impressive progress in the origin of life field, it is

probably fair to say that none of the numerous gasphase, liquid-phase or gas/liquid-solid phase reactions that have been studied in depth so far have led to

a breakthrough in our understanding. A major shortcoming of all prior experiments is that they tend not to

produce the complex organic molecules that early life

most probably needed to get started. Either nature is

so complicated that we become more confused the

deeper we penetrate into the question of the origin of

life or we miss something fundamental.

This project takes a fresh, unconventional look at

the mechanisms by which organic molecules can be

made abiogenically, in particular complex organic

molecules. We want to test the proposition that magmatic minerals are a medium in which precursor

organic molecules are formed and are then liberated

when the minerals are washed and weathered away.

Magrnatic minerals are, as their name suggests,

unlikely candidates to allow for the formation of delicate organic molecules. Magmatic minerals crystallize

under fiery conditions from molten rocks at red hot

temperatures. However, as they crystallize, they also

dissolve H20 and CO2 in their crystal structures. As

the rocks that contain these minerals are uplifted

toward the surface of the Earth, they cool and decompress. Strange things happen during the cooling and

decompression when the gases exsolve.

Recent studies on model systems, in particular

simple MgO and CaO crystals, have demonstrated that

structurally dissolved H20 (and probably CO2) are

prone to undergo a redox conversion inside the

mineral matrix forming H2 (and reduced C) plus

peroxy. This means that the original H20 and CO2

molecules split into a reduced half and an oxidized

half. During exsolution the reduced half, H2 and C,

will be separated from the oxidized half, the peroxy

which stays in the mineral matrix. As H2 and C

exsolve, they are also likely to react with each other

when they arrive at major lattice defects such as

dislocations and subgrain boundaries. There, they

form precursor entities of the sort (HxCyOz) n-, which

in turn should yield organic molecules when the

minerals are weathered. Since this reaction takes place

inside a two-dimensionally structured matrix, the

organic molecules thus formed can be complex and

can be stereochemically restrained-- both apparent

prerequisites of early biochemistry.

The challenge of the work undertaken in this DDF

project is to prove experimentally that the proposition

presented above is valid and that it leads to complex

organic molecules that can be distinguished from

omnipresent contamination by today's biomolecules in

the environment.

A 10 kW carbon arc fusion furnace has been set up

to melt simple oxides like MgO and CaO and grow

large single crystals from the melt. So far we have

obtained small single crystals. We are in the process of

improving the technique and hope to have the crystal

growth procedure under control soon so that we may

use isotopically labeled D20 and 13CO2 for incorporating into the crystals.

We also developed, in collaboration with the

Balazs Analytical Laboratories, Sunnyvale, Calif., a

procedure to determine the total organic carbon (TOC)

content in our crystals. According to current results,

large MgO single crystals that were grown by the

same technique by Spicer Ltd. in England do contain

up to 55 parts per million (ppm) organic carbon. This

concentration is very high and, if confirmed, would

already in itself lend the strongest support to our

unconventional proposition.

We have also developed and tested a new analytical technique to determine the peroxy content in our

crystals and, more importantly, in natural minerals

and volcanic gases. In addition, we have collected

organic gases that are released during fracture of natural minerals from the upper mantle either in ultrahigh

vacuum or under nitrogen + hydrogen gas in a specially designed all stainless steel and titanium "coffee

grinder." In collaboration with Peter Palmer these

gases have been analyzed by gas chromatography and

mass spectroscopy. Very encouraging results have

been obtained. A collaboration has been established

56
with Bernd Simoneit of Oregon State University at

Corvallis to begin during FY95 an indepth study of

samples that we will prepare at Ames Research Center

under a variety of gases, in particular deuterated gases

that can interact with the precursor organic entities.

We shall continue our work on the carbon arc

fusion furnace, continue and improve the peroxy and

TOC analyses, and continue our crushing and grinding experiments to collect gases from minerals. During

FY95 we hope to enroll the help of Alka Gupta who, as

an organic chemist, will dedicate about 50 percent of

her time to developing much needed analytical procedures for the detection of complex, highly oxygenated

organic molecules.

Keywords

Origin of life, Organic synthesis, Abiogenic synthesis,

Minerals

57
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

Other personnel involved

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. Demonstrated the viability of using the birefringent response of LCP coatings as a basis for aerodynamic shear stress measurements.

2. In order to quantitatively evaluate LCP coatings, a new benchtop flow chamber apparatus was

designed and fabricated to produce a known shear

stress level of high accuracy and of a magnitude comparable to that found in large scale testing.

3. Because imaging apparatus noise was identified as a major problem in the measurement, a new

imaging apparatus has been designed and is under

fabrication to reduce noise in the measurement.

4. Liquid crystal co-polymers (LCCP) are under

evaluation as a basis for shear sensitive coatings.

Significance of the results

The LCP approach 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.

Keywords

Aeronautical sensor, Aerodynamic shear stress

measurement, Liquid crystal polymer

58
Impacts of Automated Differentiation on Numerical Design

Optimization

Investigator(s)

Hirokazu Miura, Ames Research Center,

Moffett Field, CA 94035-1000

Ilan Kroo, Stanford University,

Palo Alto, CA 94305

Other personnel involved

Steve Altus, Stanford University,

Palo Alto, CA 94305

optimization performed on the three networked

workstations at Stanford University.

Significance of the results

Collaborative design synthesis on a distributed computing facility was demonstrated to be feasible and

reasonably efficient. However, the convergence characteristics are not as spectacular as expected, thus

there is still more work to investigate the basic nature

of the new architecture.

Objectives of the study

Aircraft design is a highly complex nonhierarchical

process with intricate interactions among disciplines.

We are trying to find a hierarchical program architecture that is amenable to parallel computation on

multiple workstations on a local network.

Progress and results

Two types of program architecture were tested and

one architecture was made operational for design

Publications resulting from study

Kroo, I.; Altus, S.; Braun, R.; Gage, P.; and Sobieski, I.:

Multidisciplinary Optimization Methods for

Aircraft Preliminary Design. AIAA-94-4325-CP,

presented at 5th AIAA/NASA/USAF/ISSMO

Symposium on Multidisciplinary Analysis and

Optimization, Panama Beach, Fla., Sept. 7-9, 1994.

Keywords

Aircraft design, Collaborated design, Automatic

differentiation

59
The Opacity of Water Vapor

Investigator(s)

Harry Partridge and David Schwenke,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The objective of this research is to determine accurate

opacities for hot water vapor, which are required for

modeling the atmospheres of oxygen-rich cool evolved

stars (CES). The relatively low surface temperature of

these stars results in a high concentration of molecular

species in their atmospheres and the spectra of these

stars are dominated by many overlapping molecular

bands. Considerable effort has been devoted to constructing model atmospheres of CES, but progress is

limited by the lack of accurate opacities for water

vapor at stellar temperatures. The available laboratory

data are insufficient to accurately specify the opacities.

However, the required opacity data can be obtained by

quantum mechanical calculations that solve both the

electronic and the nuclear Schroedinger equations.

This project involves three principal steps: 1) determination of an accurate dipole moment surface for water;

2) development of a hybrid potential energy surface

for water using the accurate experimental potential

near the equilibrium geometry and the ab initio results

for highly distorted geometries; and 3) determination

of the ro-vibrational energy levels and their intensities

for all levels that are significantly populated at stellar

temperatures.

Progress and results

The ab initio electronic structure calculations to

determine the dipole moment and energy surfaces

are nearly complete; approximately 600 geometries

were needed to represent the surfaces. The computed energy surface is in excellent agreement with

the experimentally derived surface up to about

20,000 cm -1, which represents the energy regions for

which spectroscopic data are available. At energies in

the region 25,000 to 40,000 cm -1, substantial errors are

obtained by simply extrapolating the experimental

potential.

Significance of the results

The computed energy surface has been shown to agree

with the experimentally derived surface in regions

where it is well defined. This gives confidence that the

computed dipole and energy surface are accurate. This

will permit the development of a hybrid potential

energy surface that will incorporate the experimental

data and extend the surface to higher energies (higher

temperatures). Given an accurate potential energy and

dipole moment surface, we will solve the nuclear

Schroedinger equation to determine the to-vibrational

spectrum and intensities. The goal is to compute the

line intensities for all the levels populated at stellar

temperatures. The opacity data will be generated in a

format that is consistent with the Code S opacity

codes.

Key'words

Opacity, Water

6O
An Ultralow-Temperature Thin-Film Thermometer

Investigator(s)

Pat R. Roach, Ames Research Center, Moffett

Field, CA 94035-1000

Other personnel involved

AI Spivak and Mic Clark, Trans-Bay Electronics,

Inc., Ames Research Center

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 for this

range that are reliable, accurate, and simple enough

for unattended operation in an orbiting telescope. We

want to develop a thin-film resistance thermometer

that is accurate, sensitive, and reproducible after

cycling to room temperature. Because it is 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. If a thin-film serpentine pattern of Au-A1 alloy

is created that varies in its composition from 86% Au14% A1 (which superconducts at 0.38 K) to 96% Au-4%

Al (which superconducts at 0.01 K), then there will be

a continuous decrease in resistance of the pattern as

the temperature of the thermometer is lowered from

0.38 K to 0.01 K because more and more of the film

will become superconducting.

The objectives are:

1. Design the serpentine pattern to maximize the

pattern length and area of thermal contact in a small

package.

2. Evaporate the gold and aluminum films in the

correct composition gradient.

3. Etch the pattern in the film and diffuse the Au

and Al 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.

Our initial work indicated that it was a problem to

get the gold-aluminum alloy to bond to the sapphire

substrate and that the attachment of leads to the film

was difficult. For these reasons we consulted with a

leading manufacturer of thin-film low-temperature

thermometers, Lake Shore Cryotronics, Inc., in

Westerville, Ohio. They agreed to fabricate the thermometers for us. They suggested using an existing

pattern that they had used before, although it was

much smaller than the one we had designed. This

pattern is shown in figure 1.

Their experience in working with thin films of

gold suggested a solution to the problem of adherence

to the substrate: a very thin film of hafnium was first

deposited on the substrate before the gold and aluminum. They also suggested a method for creating the

gradient in the aluminum concentration. After the

uniform gold layer was deposited by high-vacuum

.2

0.150" _l

Figure 1. Thin-film resistor pattern used for superconducting thermometer.

61
evaporation, a special moving mask was used for the

deposition of the aluminum. This mask had a triangular hole in it that passed over the substrate, as shown

in figure 2. The mask allowed the continuously evaporating aluminum to reach the substrate only ;¢¢here

there was a cut-out. At the narrow point of the triangle

very little aluminum was deposited during the pass of

the mask over the substrate, whereas at the broad end

a much larger amount was laid down. With this

geometry, each narrow line of the resistor pattern has

a concentration gradient from one end to the other.

After deposition, the gold and aluminum were diffused together at high temperature. Then the serpentine pattern was etched into the film and leads were

attached to the large pads by thermosonic ball

bonding.

Eight of these thermometers have been made and

they have ailbeen checked at room temperature, 77 K,

and 4.2 K. Their resistances go from approximately

1,000 f_ at room temperature to approximately 800

at 4.2 K. The lastest modifications of our lowtemperature refrigerator, a He3-He4 dilution cooler,

have almost been completed, and it will be used to test

the thermometers soon.

To date we have demonstrated that thermometers

of the appropriate configuration can be fabricated.

These thermometers are relatively rugged and have

leads on them that withstand considerable handling.

The low-temperature testing to be conducted soon will

answer the crucial questions about their sensitivity,

reproducibility, and actual operating range of

temperature.

Keywords

Resistance thermometer, Low temperature,

Superconducting thin film

v

Motion of mask

Figure 2. Mask for evaporating a gradient of aluminum onto substrate. The pattern shown is where the film will be etched

after evaporation.

62
Deep Near-Infrared Cosmological Surveys

Investigator(s)

Thomas L. Roellig and Edwin F. Erickson,

Ames Research Center,

Moffett Field, CA 94035-1000

Jacqueline A. Davidson, SETI Institute,

Ames Research Center

Other personnel involved

Arati Chokshi, Infrared Processing and

Analysis Center and The Indian Centre for

Astrophysics, California Institute of Technology,

Pasadena, CA 91125

Objectives of the study

Imaging measurements of distant galaxies can serve as

an excellent probe of the space-time curvature of the

universe if galaxies are uniformly distributed throughout space on a sufficiently large scale. Therefore, measurements of distant galaxies can help answer one of

the most important questions in cosmology: whether

the universe is open and will continue expanding for-

. ever, or closed, in which case it will eventually stop

expanding and instead collapse again in a "BigCrunch." These measurements can also set strong

constraints on the existence of the various exotic

particles (such as WIMPS, MACHOS, etc.) that have

been postulated to be responsible for the missing mass

in the universe. Our objective is to determine the

envelope of parameters within which near-infrared

imaging surveys with a small dedicated space mission

will have the maximum impact on cosmology studies.

Progress and results

In the first year of this study we have generated a

detailed model of galaxies as they would appear in

both closed and open universes. This model accurately

depicts the appearance of spiral, elliptical, and irregular

galaxies in the 1-10 pm wavelength range out to red

shifts of 3.0. We have used this model to probe the

ability of a dedicated space mission to take deep nearinfrared images to get number counts of galaxies. Our

preliminary findings indicate that, in order to discriminate between open and closed universes, such a mission would require: 1) good sensitivity, 2) sensitivity to

wavelengths longer than 5 _ to be able to measure the

red shift of galaxies with red shift z greater than -1.5,

3) sampling at wavelengths spaced no more than 1 bLm

apart in order to eliminate excess noise in the total

number N versus z plots, and 4) very accurate estimates

of galaxy merger rates. In the coming year we will

investigate the effects of source confusion, work at

removing some small systematic effects in our analysis,

and set stronger constraints on the missions size

needed to realize the observational objectives.

Keywords

Cosmology, Near-infrared imaging, Source counts

63
Utility of the Experimental Electro-Optical Camera (SPEC-T)

for Assessment of Insect rought 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. Arveson, Ames Research Center

Edward A. Hildum, SVERDRUP,

Ames Research Center

Jeffrey S. Myers, ATAC, Inc.,

Ames Research Center

Objectives of the study

Evaluate and test the application of a newly developed, high spatial resolution, electro-optical digital

camera system (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 instruments.

Progress and results

Data collection was attempted over study sites in early

June 1994, but the system was operable only for the

secondary site near Lake Tahoe, Calif. Evaluation of

this alternate data set was promising and changes to

both the focusing and exposure timing were completed. A successful data collection mission over our

primary site was completed on 25 August 1994 near

McCloud, Calif. The system, through the continuing

development resulting from these test flights, is

operating successfully and with little downtime. Our

analysis of the August data set is preliminary.

Significance of the results

The electro-optical camera has seen significant development and increased payload operations. The system, partially through the DDF support, has been

developed into a fully operational NASA instrument.

Because of its promotion instrument enhancements,

the system is continuously in demand on ER-2 flights

and it supports a wide range of research and applications missions and projects. Those projects have

included the Navy Monterey Area Ship Track (MAST)

experiment involving the ER-2 data collection and

near-shore monitoring.

The analysis phase of the insect/drought data

acquisition is currently under way with the August

1994 data sets. DDF funds from FY94 have been

forwarded to FY95 to continue the applications test.

The U.S.D.A. Forest Service is therefore interested in

the system as a potential supplement to current aerial

photography and/or unstable scanner data.

Publications resulting from study

Ambrosia, V. G.; and McKeen, J.: Utility of the ElectroOptical Camera (SPEC-T) for Assessment of

Insect/Drought Related Forest Mortality. Paper

presented at the Fifth Biennial Conference on

Remote Sensing Applications in the Forest Service,

Portland, Ore., Apr. 1994.

Keywords

Electro-optical camera, Remote sensing, Ecosystem

analysis

64
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 has developed 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 have developed a new theory and a new laser

based measurement method for remotely sensing

canopy architecture. The theoretical development has

supported 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 located above a plant canopy:

• During the first year, we developed a stochastic process model to mathematically describe canopy

architecture. We constructed state-of-the-art detectors

for use in a proof-of-concept system for measuring

canopy architecture.

• During the second year, we used the results of

our canopy architecture model to design and assemble

a proof-of-concept system.

In the 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

Background

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 GHz 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.

First year progress

During the first year, we 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-of-concept

lidar canopy architecture sensor. The MSM detectors,

the critical component in the canopy architecture

instrument, are capable of providing an output current

proportional to the incident light. In a test a sample

MSM detector exhibited a response time that would

allow the architecture of even miniature canopies to be

measured.

Second year progress

During the second year, we first assembled a proof-ofconcept measurement system that allowed us to

demonstrate the feasibility of the design approach.

Tests showed that the nonoptimized laboratory system

could resolve the distance between even closely

spaced leaves--as, for example, would be found in a

65
plant canopy having a spatially clumped leaf distribution. Because these laboratory results were extremely

encouraging, we ordered additional parts and are now

reassembling the proof-of-concept system in a package

more suitable for measurement of plant canopies.

During the coming year, in cooperation with controlled ecological life support systems (CELSS) scientists here at Ames Research Center, we plan a series of

measurements of plant canopies, grown in environment chambers, in order to better assess the advantages and limitations of the present design of our

instrument as it provides canopy structural data to

plant scientists.

Significance of the results

The progress and results to date are extremely encouraging. They have laid the foundation for our efforts to

establish a new area of remote sensing--plant canopy

structure remote sensing. Our new model for canopy

architecture provides the needed theoretical basis for

mathematically describing canopy structure. Essential

and necessary parts of the instrument, the state-of-theart MSM detectors, and detector arrays have been successfuUy fabricated. The feasibility of the instrument

design has been demonstrated using a proof-of-concept, laboratory-based system. We are now assessing

the advantages and limitations of the present instrument design applied to measurement of the structure

of CELSS plant canopies. The progress and results to

date provide an important first step in our efforts

toward gaining wide scientific recognition and acceptance of our approach to canopy architecture remote

sensing.

Publications resulting from study

A draft report, Stochastic Model of Plant Canopy

Architecture, has been written by V. C. Vanderbilt,

1993.

Keywords

Canopy architecture, Stochastic model of canopy

architecture, Measurement of canopy architecture

66
Technology Utilization of Adaptive Structures in Active

Electronic Equipment Isolation

Investigator(s)

David F. Voracek,

Dryden Flight Research Center,

Edwards, CA 93523-0273

The research involves the investigation and design of

an active isolation system for airborne electronic

equipment using adaptive structure material. The

main objective is to research and develop adaptive or

smart structure concepts and applications for use in

active vibration suppression and isolation. The specific

objectives of this research are:

• to develop and augment as necessary the current analysis, structural modeling, and applications of

adaptive structures in vibration isolation systems (use

of the materials, power requirements, and system

design are issues that must be addressed);

• to devise a process for control system design

for an active vibration isolation system; next,

• to implement the process for an active plate

isolation system for aircraft avionics and other

sensitive electronic equipment

• to prototype the flight hardware for in-flight

testing of an active vibration isolation system; and

finally,

• to flight test the prototype isolation system.

The research benefits will include the utilization of

new technologies of adaptive and smart structures. If a

viable design can be made operational, it will result in

the use of more commercially available electronic

equipment, which will reduce costs of redesigning

commercial equipment to military and NASA

specifications; reduce structural weight of the electronic equipment; reduce the time and expense of

environmental tests; prevent damage to electronic

equipment during flight or the environmental test that

could result in lost research data, delays in major

programs, or a complete shutdown of a research effort;

and finally, increase aircraft safety. Finally active

isolation will be a more robust and effective isolation

system than current passive methods.

During the first year the properties of piezoelectrics were analyzed and a study of the equipment

and control system required to use piezoelectrics in an

active damping system was completed. The results of

these studies included building a damping system for

a model aircraft wing that uses piezoelectric sensors

and actuators. Also a demonstration of a possible

active isolation system design for electronic equipment

has been manufactured and is currently in testing.

NASA Dryden Flight Research Center worked closely

with California Polytechnic State University, San Luis

Obispo, Calif., on the damping system for the model

aircraft wing. Active Control Experts, a company in

Cambridge, Massachusetts, who specializes in piezoelectric sensors, actuators, and motion control systems

worked on the demonstration model of the active isolation system design. The future plan is to finalize a

design for a flight test article, build the hardware and

control system, and then flight test the isolation

system.

Keywords

Active isolation, Smart structures, Piezoelectrics

67
Does the Collapse of Diatom Blooms Trigger

Coccolithophore Blooms?

Investigator(s)

Robert Wrigley and Lynn Rothschild,

Ames Research Center,

Moffett Field, CA 94035-1000

Objectives of the study

The immediate objective is to determine if there is a

causal relationship between the end of a diatom bloom

and the beginning of an Emiliania bloom, and if so,

what its chemical basis is. The ultimate objective is to

predict the onset of Emiliania blooms to better monitor

them by remote sensing. Our data may suggest ways

to alter the global carbon cycle by triggering or suppressing Emiliania blooms.

Progress and results

Purchased equipment vital to this study: an environmental chamber in order to grow cells under simulated natural light and temperature conditions; a

Coulter Counter, which allows quick and accurate cell

counts; and an upgrade to a compound microscope,

which allows visualization of the coccoliths on

Emiliania.

Obtained cultures of diatoms and Emiliania. Some

have been successfully established on the artificial

seawater medium whereas others seem to grow only

on enriched seawater.

Significance of the results

Many of the phytoplankton obtained do not seem to

grow in the defined seawater, probably because they

need trace compounds that are not being added. For

this reason, it is likely that the experiments will have

to be conducted in actual seawater.

Publications resulting from study

Rothschild, L. J. : CO 2 and Diatom Mats. Nature,

vol. 368, 1994, p. 817.

Keywords

Coccolithophores, Plankton blooms, Carbon cycle

68
APPENDIX A-1

FINAL REPORTS

For each of the 12 projects completed in FY94, a brief description and the financial distribution follow. The reports

are arranged alphabetically by the last name of the primary investigator.

Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

Title o! 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 FY93 Expected completion date FY94

Total prior to FY94 _40,000 Authorized in FY94 $37r000

Total expended in FY94:$37,000 (Estimated) Requested for FY95, ifany

In-house $20,000

Contracts (identify) $17,000 (Electron microscope maintenance and support)

Grants (identify)

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitionedto other funding, to RTOP (number?.)

to Program (name?)

[] Continued in F--Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The purpose of this investigation is to grow and study the structure of the crystalline hydrates of nitric acid that are

thought to be present in polar stratospheric clouds (PSCs). PSCs are thought to be responsible for chlorine activation in

the Antarctic stratosphere and its subsequent catalytic destruction of ozone. By understanding the crystal structure

and properties of these hydrates, we may be able to predict how and why chlorine activation occurs and whether

increased anthropogenic use of the stratosophere will lead to ozone depletion in other parts of the stratosphere.

FY94 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Blake, D. F.: Laboratory Investigation of the Growth and Crystal Structure of Nitric Acid Hydrates by Transmission

Electron Microscopy (TEM). Paper presented at the Atmospheric Effects of Stratospheric Aircraft (AESA) meeting,

Virgina Beach, Va., June 1994.

Planned future work

I will continue experimentation using the apparatus built with DDF money. ] have prepared a grant proposal that

will be submitted either to phase II of the High Speed Research Program or to the Innovative Research Program

(NRA 94-OSS-16).

Prepared by David F. Blake Org. Code SSX M/S 239-4 Phone (415) 604-4816

71
Ames Research Center

Final Report

Director's Discretionary Fund Report Fiscal Year 1994

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 F'Y93

Total prior to FY94 $30,00(_

Total expended in FY94: $40,000

In-house

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY94

Authorized in FY94 $40,000

Requested for FY95. ifany

Status of study [] Completed in F'Y94

If continued in F'Y95 [] with funds remaining?

Iftransitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in F-'Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

To develop a method to link remote sensing data to modern pollen data, and to generate predictive tools and use

them to hindcast paleoenvironmental data that can provide larger time windows to current models of global change.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

D'Antoni, H. L.; and Spanner, M. A.: Remote Sensing and Modern Pollen Dispersal in Southern Patagonia and Tierra

del Fuego (Argentina): Models for Palaeoecology. Grana, vol. 32, 1993, pp. 29-39.

D'Antoni, H. L.: Pollen Analysis in Southern Patagonia: From Space to Time. Paper presented at the 26th Meeting of

the American Association of Stratigraphic Palynologists, San Diego, Calif., 1992.

D'Antoni, H. L.: Remote Sensing and Palaeoecology in Southern Patagonia. Proceedings of the 3rd Symposium on

South America, Landscape Development, Paleoecology and Climate History of the Arid Diagonal of Southern America in

the Recent Quaternary, Bamberg, Germany, July 1994.

D'Antoni, H. L.: Paleotemperatures of La Malinche: A Palynological Hypothesis. Grana, vol. 32, 1993, pp. 354-358.

D*Antoni et al.: Effects of Stratospheric Ozone Depletion and Increased Levels of Ultraviolet Radiation on Subantarctic

Forests and Western Patagonian Steppe: A Research Project in Stratospheric Ozone Depletion/UV-B Radiation in the

Biosphere, R. H. Biggs and M. E. B. Joyner, eds., NATO ASI Series I, vol. 18, Springer-Verlag, Berlin, 1994, pp. 81-96.

Planned future work

Further analyses of data produced by this project and further publication in peer-reviewed journals. A new

research line was developed during this project and research work is under way now.

Prepared by H. D'Antoni Org. Code SGE M/S 239-20 Phone (415) 604-5149

72
Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

Title of Investigation Schmidt-Cassegl"ain Long-Range Laser Velocimeter

Investigator(s) (show affiliation) Stephen E. Dunagan, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY93 Expected completion date FYg't

Total priorto F'Y94 _ _37.000 Authorized in F'Y94 $38.000

Total expended in F-Y94: (Estimated) Requested for FY95, if any

In-house $38,000

Contracts (identify)

Grants (identify)

Status of study [] Completed in F-Y94

If continued in FY95 [] with funds remaining?

If transitionedto other lunding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

This investigation has been directed at the development of a new long-range laser velocimeter instrument to

provide multi-application velocity field measurement capability for wind tunnel studies conducted in the National

Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Subsonic Wind Tunnel. The instrument incorporates new

technologies including precision telescope optics, fiber optics for both laser beam and signal transmission, and digital

signal processing to enhance data rate and accuracy.

F-'Y94applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

The study has produced an instrument utilizing the above mentioned technologies. The instrument has been

designed (including stress analysis), fabricated, assembled, and tested in the optics laboratory. This instrument is

intended for general on-demand application in a broad variety of test programs. A meeting paper describing the

instrument design and operation will be presented at the AIAA 33rd Annual Aerospace Sciences Meeting in Reno,

Nev., Jan. 1995.

Planned future work

Future enhancements include designing and fabricating a two-dimensional traverse to provide full test section

access, and investigating the potential for improved signal processing using digital autocorrelation techniques.

Prepared by Stephen E. Dunagan Org. Code FFR M/S T-12/B Phone (415) 604-4560

73
Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

Title of Investigation Detection of Life Forms: Extant, Dormant, or Extinct

Investigator(s) (show affiliation) Rosalind A. Grymes and Christine Sawyer, Ames Research Center,

Moffett Field, CA 94035-1000; Jay Shafto, Pomona College, Claremont, CA 91711

Funding Year Initiated FY93

Total prior to FY94 _401000

Total expended in FY94:

In-house $40,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date

Authorized in F-'Y94

Requested for FY95, if any

FY94

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in F--Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

These studies evaluated parameters affecting randomly primed polymerase chain reaction (PCR) protocols.

Nucleic acids are the genetic information common to all life on Earth. Without prior knowledge of the biological

attributes of the living sample, it is possible to amplify a single nucleic acid molecuIe derived from that sample (extant

or extinct) up to 105 times, achieving levels of the amplified material that are easily amenable to scientific study and

manipulation. Since the PCR process depends on an initial priming step, amplification of unknown material can only

be successful if the parameters governing randomly primed reactions are evaluated.

F-Y94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

None-This was a feasibility study. We demonstrated the applicability of this approach, and of molecular biology

methods in genera], to the detailed study of the types of samples generated by 'life in extreme environments' scientists.

This laboratory is equipped to support such investigations, but the primary search for funding, and the scientific

objectives, must be defined by the principal investigators of those studies. We have spoken widely with scientists from

the (former) Space Sciences Division, and they are aware of the possibilities opened by our work.

Planned future work

None specifically, although we will pursue as time permits the further problem of recovering nucleic samples from

soil colloids.

Prepared by Rose Grymes Org. Code SLR M/S 239-11 Phone (415) 604-3239

74
Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

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

Steve Hipskind, Ames Research Center, Moffett Field, CA 94035-1000; Kathy Pagan,

Investigator(s) (show affiliation) San Francisco State University, Ames Research Center; Oswaldo Garcia and Patricia Foschi,

San Francisco State University, San Francisco, CA 94132; Steve Gaines, Sterling Software,

Ames Research Center

Funding Year Initiated FY93

Total prior to FY94 $33,000

Total expended in FY94:$40,000

In-house

Contracts (identify)

Grants (identify) $40,000

(Estimated)

SFSU JRI

Expected completion date FY94

Authorized in FYg4 $401000

Requested Ior FY95, if any

Status of study [] Completed in FY94 [] Continued in FY95

If continued in FY95 [] with funds remaining? [] with FY95 funds?

If transitioned to other funding, to RTOP (number?.) 665-25-10

to Program (name?) UARS Guest Investigator Program to Other (identify)

Purpose of investigation

Determine whether advanced very high resolution radiometer (AVHRR) imagery can be used to detect polar

stratospheric clouds (PSCs) over Antarctica. If so, determine date of PSC onset and develop climatology of duration

and geographical extent of PSCs.

FY94 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Pagan, K.; Garcia, O.; Foschi, P.; Mergenthaler, J.; Kumer, J.; Roche, A.; Gaines, S.; and Hipskind, R. S.: Detection of Polar

Stratospheric Clouds over Antarctica Using AVHRR, CLAES, Radiosonde and Surface Automatic Weather Station Data.

Seventh Conference on Satellite Meteorology and Oceanography, Preprint Volume, Monterey, Calif., June 1994, pp. ]19-J22.

Garcia, O.; Pagan, K.; Foschi, P.; Gaines, S.; and Hipskind, R. S.: Detection of Polar Stratospheric Clouds Over Antarctica

Using AVHRR Images Obtained at Palmer Station During August 1992. Under review by the Polar Record.

Planned future work

Conduct intercomparisons with other data sets (various Upper Atmospheric Research Satellite (UARS) instruments).

Develop algorithms for detection of optically thin PSCs. Develop automated classification system for PSC detection in

order to assemble long-term climatology of PSCs over Antarctica. Extend research to detect PSCs over Arctic region.

Prepared by Steve Hipskind Org. Code SGA M/S 245-5 Phone (415) 604-5076

75 °
Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

Title of Investigation Ablating Surface Heat Transfer Estimation for Flight Application

Jnvestigatoq's) _show affiliation) Greg Noffz and Mike Bowman, Dryden FlJght Research Center, Edwards, CA 93523-0273

Funding Year Initiated FY92

Total prior to FY94 $80t 000

Total exPended in FY94:

In-house $40,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY94

Authorized in FY94 $40r000

Requested for FY95, if any

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] withFY95 funds?

to Other (identify)

Purpose of investigation

To develop a capacitive gage capable of measuring the recession rate of thin layered ablators, thus allowing an

estimation of convective heat transfer in aeroheating/ablation environments. Aspects of gage development include

circuitry development, gage face geometry, packaging and shielding, testing and calibration, finite element modeling,

and materials.

FY94 applications el results, patents, reports/publications,papers at meetings, any awards received, etc.

Noffz, Gregory: Development of a Capacitive Gage for Measuring the Recession of a Thin-Layered Ablator. Master's

Thesis, University of California at Los Angeles, 1994.

Patent application in progress.

NASA TM in progress.

Planned future work

Construct a "ceramic" gage capable of operating at higher temperatures.

Prepared by _Gre_ Noffz Org. Code XRA M/S D-2033 Phone (805) 258-2417

" 76
Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

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;

Ute Fischer, Kimberly Jobe, and Michael Wich, San Jose State University Foundation,

San Jose, CA 95192

Funding Year Initiated FY93 Expected completion date FY94

Total prior to F-'Yg4 _40,000 Authorized in F"Y94 .$40t000

Total expended in FY94: $40,000 (Estimated) Requested for FY95, if any

In-house $40,000 (through San Jose State University Foundation)

Contracts (identify)

Grants (identily)

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in F-Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

This project is motivated by two factors: the significant 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.

F-Y94applications 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

findings, methods, and concepts include hospital emergency shock/trauma centers, nuclear power, offshore oil drilling,

and merchant marine.

Ten presentations at professional meetings and four publications have resulted from this project (see text for complete list). These include invited addresses at the International Air Transport Association (IATA) Conference on Human

Factors in Aviation, the International Civil Aviation Organization (ICAO) Regional Safety Seminars in Amsterdam and

Addis Ababa, and a request to=serve as an expert witness on crew decision making at a public hearing by the National

Transportation Safety Board.

Planned future work

Conduct experiments to test hypotheses about sources of judgment and decision error (especially situational ambiguity and faulty risk assessment).

Test validity of effective decision strategies through training studies.

Prepared by Judith Oransanu Org. Code AFO M/S 262-4 Phone (415) 604-3404_

77
Ames Research Center

Final Report

Director's Discretionary Fund Report Fiscal Year 1994

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

Funding Year Initiated FY92

Total prior to FY94 _01000

Total expended in FY94:

In-house $50,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY94

Authorized in FY94 $50r000

Requested for F-Y95, if any

Status of study [] Completed in FY94

If continued in F'Y95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The objective of this study was 1) to evaluate the existing computational fluid dynamics (CFD) codes and their

capabilities in reproducing and analyzing the experimental spectra, and 2) to analyze the spectral emission spectra

obtained from the shock layer over a fiat disk model placed in the 20 MW arc-jet wind tunnel. Through the computations

we were able to better identify the thermochemical nonequilibrium processes in the nozzle and behind the shock wave

over a blunt body and develop a procedure for determining the flow-field enthaipy based on the non-intrusive spectral

emission measurements.

FY94 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Babikian, D. S.; Park, C.; and Raiche, G. A.: Spectroscopic Determination of Enthalpy in an Arc-Jet Wind Tunnel.

Presented at 33rd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nev., Jan. 1995.

Planned future work

Prepared by Dikran Babikian Org Code STA M/S 230-2 , Phone (415) 604-1144

78
N/liSA Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

Title of Investigation Three-Dimensional (3-D) Disturbances Generated by Suction Holes for Laminar Flow Control (LFC)

Investigator(s) (show affiliation) Daniel C. Reda, Ames Research Center, Moffett Field, CA 94035-1000;

Jonathan H. Watmuff, MCAT Institute, Ames Research Center

Funding Year Initiated FY93

Total priorto F-Y94 :_40,000

Total expended in F'Y94:$40,000

In-house $40,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY94

Authorized in FY94 $'_r 000

Requested for FY95, if any

Status of study [] Completed in FY94

If continued in FY95 [] with fundsremaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in F'Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

To investigate the characteristics of boundary layer disturbances in the vicinity of suction holes and to explore the

conditions under which the disturbances amplify or decay as they propagate downstream.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Watmuff, Jonathan H.: 3D Disturbances Generated by Suction Holes for Laminar Flow Control (LFC). Annual

Report to MCAT Institute, Aug. 1994.

Planned future work

Apply techniques and knowledge gained from DDF supported isolated hole studies to fully porous surface

consisting of 8,466 discrete suction holes.

Prepared by Jonathan H. Watmuff Org. Code ADF/MCAT M/S 260-1 Phone (415) 604-4150

79
Ames Research Center

Final Report

Director's Discretionary Fund Report Fiscal Year 1994

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

Total prior to FY94 $23,000

Total expended in FY94:

In-house $20,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date

Authorized in FY94

Requested for FY95, if any

FY94

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

To develop a sensitive capacitance transducer to measure shear forces over a vehicle in an air stream. A significant

result of the study was the observation of a "nonlinear" period of oil wedge thinning. The initial rapid thinning behavior

implies that significant pressure forces are present in addition to shear forces.

F'Y94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

A U.S. patent application was filed on April 26, 1994, entitled "Ice detector and deicing fluid effectiveness monitoring

system."

Planned future work

None

Prepared by S.R. Lan_;hoff Org. Code STC INS 230-3 Phone (415) 604-6213

8O
Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

Title of Investigation Effects of Atomic Oxygen and Nitrogen on Advanced Thermal Protection Materials

Investigator(s) (show affiliation) Susan White, Ames Research Center, Moffett Field, CA 94035-1000;

Joan Pallix and Les Barnes, Thermosciences Institute, Ames Research Center

Funding Year Initiated FY93 Expected completion date F'_'94

Total prior to FY94 $40.000 Authorized in FY94 $40.000

Total expended in FY94: (Estimated) Requested for FY95, if any

In-house $15,000

Contracts (identify) $25,000 (SRI Contract No. POA40537D)

Grants (identify)

Status of study [] Completed in FY94

If continued in F'Y95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?) Access to Space

242-20-02

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The goal of this work was to develop state-of-the-art experimental methods to study the physical processes that

control surface heating due to surface mediated atom recombination. An experimental technique was developed to study

atom recombination processes using la,ser-induced fluorescence (LIF) detection of atomic and molecular concentration

gradients in a flow/diffusion reactor.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

This feasibility study has resulted in a design for a versatile laser based flow/diffusion reactor, which has been

constructed and successfully demonstrated. The preliminary work was carried out using equipment available at SRI

International (in collaboration with Richard Copeland). A laser laboratory is currently under construction at Ames

Research Center so that this reactor and laser system can be permanently installed for testing of newly developed

thermal protection materials. The work was presented at the VIII High Temperature Materials Conference in April 1994

in Vienna, Austria. A journal article describing the technique and potential applications is currently being prepared for

submission to the Journal of Spacecraft and Rockets.

Planned future work

Work planned for DDF funding is complete. The technique developed with DDF funding will be useful to a

number of NASA programs. Work to be done in the near future will be funded by the NASA Access to Space Program.

The work will involve characterization of new materials using the laser based diagnostic technique.

Prepared by Joan Pallix Org. Code STM M/S 234-1 Phone (415) 604-0332

81
Final Report

AmesResearchCenter Director's Discretionary Fund Report Fiscal Year 1994

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 Right Research Center, Edwards, CA 93523-0273

Funding Year Initiated FY93

Total prior to F'Yg4 _0.000

Total expended in FY94:$40,000 (Estimated)

In-house $25,000

Contracts (identify) $15,000 UCLA(s)

Grants (identify)

Expected completion date FY94

Authorized in FYg4 _J0,000

Requested for FY95, if any

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FYO5 funds?

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.

FY94 applications el results, patents, reports/publications, papers at meetings, any awards received, etc.

DRAFT: Flight Measurement of the Near-Field SR-71 Sonic Boom Signature Using Optimal De-Convolution of

Noseboom Measured Pitot-Static Pressure Data;

The Effects of Large Temperature Gradients and Ratified Row Conditions on the Dynamic Responses of Pressure

Measuring Devices.

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 M/S D-2033 Phone (805) 258-2002

82
APPENDIX A-2

ONGOING REPORTS

For each of the 22 ongoing projects sponsored in FY94, a brief description and the financial distribution and status

follow. The reports are arranged alphabetically by the last name of the primary investigator.

[_ Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

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, Ames Research Center

Funding Year Initiated FY93 Expected completion date FY96

Total priorto FY94 $40r000 Authorized in F'Y94

Total expended in FY94:$40,000 (Estimated) Requested for FY95. if any

In-house $7,000

Contracts (identify) $33,000 Maintenance/repair and upgrade of electron microscope

Grants (identify)

Status of study [] Completed in FY94 [] Continued in FY95

If continued in FY95 [] with fundsremaining? [] with FY95 funds?

If transitioned to other funding, to RTOP (number?) 185-52-32-08

to Program (name?) NASA Exobiology. to Other (identify) NRC Post-dec

Purpose of investigation

To evaluate the factors that control the preservation (fossilization) of organic materials in thermal springs and to use

this knowledge to develop a basis for interpreting the fossil record of ancient rocks on Earth. To apply the insights

gained toward developing an exploration strategy to search for an ancient biosphere on Mars during upcoming missions.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Farmer, J. D.; and Des Marais, D. J.: Biological Versus inorganic Processes in Stromatolite Morphogenesis: Observations from Mineralizing Systems. In Microbial Mats: Structure, Development and Environmental Significance, L. J. Stal

and P. Caumette, eds., NATO ASI Series in Ecological Sciences, Springer Verlag, 1994.

Farmer, J. D.; Des Marais, D. J.; Blake, D. F.; Walter, M. R.; and Hinman, N. W.: Paleobiology, Mineralogy, and

Geochemistry of Modern and Ancient Thermal Spring Deposits and Their Recognition on Early Earth and Mars.

Fifth Symposium on Chemical Evolution and the Origin of Life, and Workshop on Mars Exobiology Science

Strategy, NASA Ames Research Center, April 25-29, 1994.

Farmer, J. D.; and Des Marais, D. J.: Exopaleontology and the Search for a Fossil Record on Mars. Lunar

Planetary Science, vol. 25, 1994, pp. 367-368.

Roles of Biology, Sedimentation, and Diagenesis in Determining Stromatolite Microstructure. Harvard Stromatolite Workshop, Botanical Museum, Harvard University, Cambridge, Mass., Oct. 18-21, 1993.

Farmer, Jack D.: High Resolution Transmission Electron Microscopy. Sponsored by the Mineralogical Soc. of

America, Miami, Ohio, Oct. 1992.

NASA Ames Space Science Division, Contractor Recognition Award to Jack D. Farmer, 1994.

NASA Ames Space Science Division, Contractor Recognition Award to Jack D. Farmer, 1993.

Planned future work

We plan to continue the project by investigating the preservation over a broader range of temperature and pH, and to expand

the systems studied to include carbonate and iron springs.

Prepared by David F. Blake Org. Code SSX M/S 239-4 Phone (415) 604-4816

85

__'_ PAG[; IBLAN¥, HOt" flL_;,;_ PAGE % 4 ,_INTENT!ONALtY rJLA_,]K
Fiscal Year 1994

Ames Research Center Director's Discretionary Fund Report

Title of Investigation Isotopic Analysis of Meteoritic organosulfur and Organophosphorous Compounds

Investigator(s) (show affiliation) Sherwood Chang, Ames Research Center, Moffett Field, CA 94035-1000;

George Cooper, National Research Council Postdoctoral Associate, Ames Research Center

Funding Year Initiated F'Y94

Total prior to FY94

Total expended in FY94:$40,000

In-house $40,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date F_'96

Authorized in FYg4 _40,000

Requested for FY95, ifany 1540,000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The purpose of the investigation was to measure the stable isotope compositions of the elements carbon, hydrogen,

and sulfur in the organic sulfonates and phosphonates of Murchison carbonaceous meteorite to determine their possible interstellar origins, as indicated by highly anomalous isotope ratios relative to solar system values. The observation of such isotopic anomalies would demonstrate that all the main elements used by biology originated, at least in

part, in the interstellar cloud of gas and dust that gave rise to the solar system. Furthermore, laboratory capabilities

were to be developed to enable in-house analysis of phosphonates and sulfonates.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Cooper, George: Carbon Isotopic Composition of Organic Sulfonates for Murchison Meteorite. Paper presented at

the 1994 Gordon Research Conference on the Origin of Life, Newport, R. I., Aug. 1994.

Planned future work

Work on the isotopic compositions of hydrogen and sulfur in these meteoritic organic compounds will be completed using apparatus built and instruments acquired with DDF funds. A research proposal will be prepared and

submitted to the Planetary Materials and Geochemistry Program for funding of additional work in this area.

Prepared by Sherwood Chang Org. Code SSX M/S 239-4 Phone (415) 604-5733

86
Ames Research Center

Fiscal Year 1994

Director's Discretionary Fund Report

Title of Investigation Robust Nonlinear Control and Guidance System Design Methods

Investigator(s) (show affiliation) Victor H. L. Cheng and Chima E. Njaka, Ames Research Center, Moffett Field, CA 94035-1000;

P. K. Menon, Santa Clara University, Santa Clara, CA 95053

Funding Year Initiated FY94

Total priorto F'Y94

Total expended in FY94: (Estimated)

In-house $5,000

Contracts (identify)

Grants (identify) $30,000 (NCC2-5019)

Expected completion date FY95

Authorized in FY94 $40.000

Requested for FY95, ifany _..0.000

Status of study [] Completed in FY94

if continued in FY95 [] withfunds remaining?

If transitionedto other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The purpose of the investigation is to explore and evaluate design techniques for robust nonlinear controllers,

which will improve on the reliability and potential safety of the system to be controlled. Evaluation of the proposed

techniques is directed towards helicopter control, which was selected because of the criticality of robust performance

and stability of helicopters in ground-hugging nap-of-the-Earth (NOE) flight.

F'Y94 applications of results, patents, reporls/publications, papers at meetings, any awards received, etc.

Njaka, C. E.; Menon, P. K.; and Cheng, V. H. L.: Towards an Advanced Nonlinear Rotorcraft Flight Control System

Design. Paper presented at the 13th AIAA/IEEE Digital Avionics Systems Conference, Phoenix, Ariz., Oct. 30--Nov. 3,

1994.

During the first year of this two-year effort, a baseline controller for attitude control of the UH-60A Black Hawk

Helicopter has been designed based on the GenHel simulation model. This baseline controller constitutes part of the

robust controller to be designed with the first of two approaches to be investigated.

Planned future work

Work has already started on the second approach, for which a force/moment generation software model has been

developed to serve as an integral part of a robust nonlinear controller. The investigation will continue to complete the

robust controller designs with both approaches.

Prepared by Victor H. L. Cheng Org. Code AFA M/S 210-9 Phone (415) 604-5424

87
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report .

Title of investigation Study of Efficiency Gain and Emission Reduction in a Pulse Combustor Design for Jet Engines

Investigator,s) {show affiliation) G.S. Deiwert Ames Research Center, Moffett Field, CA 94035-1000;

J-L. Cambier and Henry G. Adelman, Thermosciences Institute, Pale Alto, CA 94303

Funding Year Initiated FY94

Total priorto FY94

Total expended in FY94: (Estimated)

In-house $40,000

Contracts (identify)

Grants (identify) $40,000 NAS2-14031

Expected completion date 1=_'I)5

Authorized in FY94 _=40.000

Requested for FY95, if any $40,000

Status of study [] Completed in FY94

If continued in FY95 [] withfunds remaining?

It transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued inFYgS

[] with FY95 funds?

to Other (identify)

Purpose of investigation

To model pulse combustors, study their principles of operation, perform systematic parametric analyses of their

performance and emission characteristics, and apply the design to high pressure gas turbines for jet engines and/or

other applications of interest to NASA.

FYg4 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

A new code is being designed for these types of studies, for rapid parametric analyses, etc., so that the final product

can be of use to the industry. The modeling has been initiated, and a generic combustor has been studied. Various cases

of forcing mechanisms have been studied, as well as various types of boundary conditions. A simplified chemical

model has been constructed.

Planned future work

Extend code to model multiple injection ports, mixing delay, and various cases of fluid recirculations. Study

various combustor geometries. Measure performance and NOx emissions.

Prepared by Deiwert/Cambier/Adelman0rg. Cede ST M/S 229-3 Phone (415) 604-6198

88
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation Biotechnological Applications of Reuseable Surface Insulation

Investigator(s) (show affiliation) Howard E. Goldstein and Daniel B. Leiser, Ames Research Center,

Moffett Field, CA 94035-1000

Funding Year Initiated FY94

Total prior to FY94

Total expended in FY94:

In-house

Contracts (identify)

Grants (identify)

$27,0O0

(Estimated)

Expected completion date FY95

Authorized in FY94 $40t000

Requested for FY95, ifany

$13,000 (Foothill/DeAnza student)

Status of study [] Completed in FY94

If continued in FYg5 ["] with fundsremaining?

If transltioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in F-Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The purpose of this investigation is to modify the characteristics of the reuseable surface insulations (PSI) used on

the Space Shuttle to improve the potential useability as a bone implant. Hundreds of thousands of orthopedic and

dental procedures requiring bone implants are performed every year because of trauma, disease, surgery, and degenerative aging processes. Modifying RSI to fill this need for a bone implant material preserving active function and

eliminating the toxicities associated with currently used hardware (i.e., metals), yet being biocompatible and resistant

to wear, corrosion, breakage, and loosening, is the goal of this study.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Preliminary results from animal implant studies have shown that the biocompatibility of RSI is very good with no

signs of rejection from the body, but the pore structure needs improvement to permit bone ingrowth. Currently we are

attempting to'open up the RSI pore structure by utilizing new processing techniques and additives.

Planned future work

Samples of RSI materials with different sizes of holes (325 microns _), 225 !1, and 150 It), mechanically and laser

derived, for implant into animals will be prepared and sterilized. The bone ingrowth into these holes will then be

examined after implantation to determine the size required for bone ingrowth. A modified material with larger pores

is also being processed, examined, and improved in homogeneity for potential addition to the animal tests scheduled

in November 1994. After opening up the pores within RSI the research will be directed towards increasing the

strength of the material while maintaining the appropriate pore structure.

Prepared by Daniel B. Leiser Org. Code STM M/S 234-1 Phone (415) 604-6076

89
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation A Long-Duration Test Flight of a Super-Pressure Balloon as a Platform for Mars Exploration

Mvestigator(s) (show affiliation) Robert M. Haber|e, G. Scott Hubbard, Lawrence C. Lemke, and Geoffrey A. Bdggs,

Ames Research Center, Moffett Field, CA 94035-1000,

James Cantrell, Utah State University, Logan, UT 84322-4140

Funding

Total prior to FY94

Total expended in FY94:

In-house

Contracts (identify)

Grants (identify)

Year Initiated _'Y94

$40,000 (Estimated)

Expected completion date FY95

Authorized in FY94 _#X).O00

Requested for FY95, if any $40,000

$40,000 (Space Dynamics Lab, Utah State University, Grant PI)

Status of study [] Completed in FY94

If continued in FYg5 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

D_rnonstrate that a super-pressure balloon made from BJaxial Nylon 6 can survive a year Jn the Earth's stratosphere at a,

altitude of 120,000 feet, where the pressure and temperature conditions are similar to those on Mars. Biaxial Nylon 6 is a new

material that is stronger, lighter, and more resistant to leakage than mylar, which is more commonly used for super-pressure

balloons.

FY94 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Previous unsuccessful attempts to launch these balloons have been analyzed, and a new design and flight test program has been

developed. The first flight, on August 30, 1994, met two of its three objectives. The flight demonstrated that the new design is

viable, and that the super-pressure margins for Biaxial Nylon 6 are greater than theoretically predicted. A full report on the results is

being prepared by the Grant PI (lames Cantrell. Utah State University).

Planned future work

Two additional flights are planned. The first one will subject the balloon to a single day/night cycle at altitude so that we can

determine the balloon's response to a changing thermal environment and its ability to remain pressurized. Data obtained from this

flight will be used to design a follow-up balloon that will carry a larger payload and will remain at altitude for at least one year.

Prepared by Robert M. Haberle Org. Code SS M/S 245;.3 Phone (415) 604-5491

9O
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation Intervertcbral Disc and Back Pain Studies Using Spinal Traction and Compression during Magnetic

Resonance Imaging

Alan R. Hargens, Ames Research Center, Moffett Field, CA 94035-1000; Gita Murthy and

Investigator(s) (show affiliation) Donald E. Watenpaugh, University of California at San Diego, Ames Research Center; Jorma Styf,

Ames Research Center; Karen J. Hutchinson, University of California at San Diego,

Ames Research Center; Douglas F. Schwandt, Bionetics, Inc., Ames Research Center

Funding Year Initiated FY94

Total prior to FY94

Total expended in FY94: (Estimated)

In-house $5,000

Contracts (identify) $30,000 (C-906)

Grants (identify) $5,000 (NCC2-852)

Expected completion date J_05

Authorized in FY94

Requested for FY95, if any $40,000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in F-Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The objectives of this research are to study intervertebral disc height, cross-sectional area, volume, and water

content during spinal traction and compression. The traction during recumbency will enable us to lengthen the spine

by an amount similar to that documented during space flight. The compression harness during recumbency will allow

us to quantify relationships between spinal loading and disc physiology and morphology. The long-term objective is to

use spinal loading and unloading to study and diagnose mechanisms of back pain.

FYg4 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Styf, J. R.; K/ilebo, P.; and Hargens, A. R.: Lumbar Intervertebral Disc Heights as Measured by Sonography. Aviation, Space, and Environmental Medicine, vol. 65, no. 5, 1994, p. A12.

Ballard, R. E.; Styf, J. R.; Watenpaugh, D. E.; Fechner, K; Haruna, Y.; Kahan, N. J.; and Hargens, A. R.: Head-Down Tilt

with Balanced Traction as a Model for Simulating Spinal Acclimation to Microgravity. Presented at the American Society for

Gravitational and Space Biology Meeting, San Francisco, Calif., Oct. 19-22, 1994.

StyL J. R.; Fechner, K.; Ballard, R. E.; Watenpaugh, D. E.; Kahan, N. J.; and Hargens, A. R.: Height Increase, Neuromuscular Function and Back Pain During 6 ° Head-Down Tilt with Traction. Aviat. Space Environ. Med. In preparation.

Haruna, Y.; StyL J. R.; Kahan, N.; and Hargens, A. R.: Hoffmann-Reflex is Delayed During 6° Head-Down Tilt with

Balanced Traction. In preparation.

Planned future work

In the next phase of this project, we will construct the spinal compression harness and use it to quantify relationships between spinal loading and disc physiology and morphology. Using ultrasonography and magnetic resonance

imaging, we hypothesize that stepwise increases in spinal loading with the compression harness will produce decrements of spinal disc height, volume, and water content. Furthermore, spinal compression will enable us to quantify

for the first time in rive the basic relationship between changes in spinal loading and disc volume. These experimental

results will yield a non-invasive estimate of disc compliance: disc compliance = Avolume/Aload.

Prepared by D. Watenpaugh Org. Code SLR M/S 239-11 Phone (415) 604-5747

91
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title oflnvbstigation Turbulent Boundary Layer Measurements on Transport Wing Wind Tunnel Models

Investigator(s) (show affiliation) Dennis A. Johnson, Ames Research Center, Moffett Field, CA 94035-1000;

Jeffrey D. Brown, E]oret Institute, Sunnyvale, CA 94087

Funding Year Initiated FY94

Total prior to FY94

Total expended in FY94:

In-house $20,000

Contracts (identify) $20,000

Grants (identify)

(Estimated)

Expected completion date FY95

Authorized in FYg4 $40,000

Requested for FY95, if any $40,000

(Cooperative Agreement, Eloret Institute)

Status of study [] Completed in FY94

It continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in F'Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

To evaluate laser Doppler velocimeter approaches for boundary layer measurements on transport wing wind tunnel

models.

FY94 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Planned future work

Prepared by Dennis A. Johnson Org. Code ADT M/S 229-1 Phone (415) 604-5399

92
Fiscal Year 1994

Ames Research Center Director's Discretionary Fund Report

Title of Investigation Right Measured Wall Pressure Fluctuations Beneath Swept Shock/Boundary Layer Interactions

Investigator(s) (show affiliation) Steven A. Johnson, Dryden Right Research Center, Edwards, CA 93523-0273

Funding

Total prior to F-Y94 $40.000

Total expended in FY94: $35,000

In-house $35,000

Contracts (identify)

Grants (identify)

Year Initiated

(Estimated)

Expected completion date FYc,:d5

Authorized in FY94 $40.000

Requested for FY95, if any

Status of study [] Completed in F'Y94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] withFY95 funds?

to Other (identify)

Purpose of investigation

The goal of the 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.

The test apparatus will be attached to an existing "flight test fixture" and mated to the underside of the NASA

Dryden F-15B aircraft. The F-15B, capable of speeds up to Mach 2.0, will serve as the carrier aircraft for the experiment.

F-Y94applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

The experiment has not flown yet. The F-15B aircraft is required to complete a short series of stability and control

flights with the flight test fixture attached before the aformentioned experiment can be flown. These flights will be

completed in the next few months.

All hardware and instrumentation for the experiment has been procured and assembled.

Planned future work

A minimum of five flights will be carried out to complete the objectives of the experiment. A NASA research

report will be written to summarize the results.

Prepared by Steven A. Johnson Org. Code XRP M/S D-2033 Phone (805) 258-3096

93
N/LRA

Ames Research Center

Fiscal Year 1994

Director's Discretionary Fund Report

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

Investigator(s) (show affiliation) Sesi Kottapalli, Ames Research Center, Moffett Field, CA 94035-1000;

Judah Milgram and Inderjit Chopra, University of Maryland, College Park, MD 20742

Funding Year Initiated FY93

Total prior to FY94 $11.500

Total expended in FY94: $28,500

In-house

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY95

Authorized in FY94 $28.500

Requested for FY95, if any $40,000

University of Maryland at College Park

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued inFY95

[] with F'Y95 funds?

to Other (identify)

Purpose of investigation

Evaluate a new passive device concept to reduce vibratory rotor hub loads. This concept is called the "dynamically

tuned blade pitch link" and is an outgrowth of the work reported earlier.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Milgram, Judah; Chopra, Inderjit; and Kottapalli, Sesi: Dynamically Tuned Blade Pitch Links for Vibration Reduction. Presented at the 50th Annual Forum of the American Helicopter Society, Washington, D.C., May 1994.

Planned future work

Evaluate the concept of dynamically tuned blade pitch links as applied to a tilt rotor configuration.

Prepared by Sesi Kottapalli Org. Code AAR M/S T12-B Phone (415) 604-3092

94
Fiscal Year 1994

Ames Research Center Director's Discretionary Fund Report

Title of Investigation Computational Fluid Dynamics (CFD) Simulation of Left Ventricular Assist Device (LVAD)

Investigator(s) (show affiliation) Dochan Kwak, Ames Research Center, Moffett Field, CA 94035-1000;

Cetin Kids, MCAT Institute, Ames Research Center

Funding Year Initiated FY94

Total prior to F-Y94

Total expended in FY94:

In-house

Contracts (identify)

Grants (identify)

(Estimated)

$22,800 MCAT (C. Kiris)

Expected completion date FY95

Authorized in FY94 $40t000

Requested for FYg5, if any $40,000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with F-Y95funds?

to Other (identify)

Purpose of investigation

This investigation is to develop and apply computational fluid dynamics (CFD) tools to simulate steady and unsteady

flows within artificial heart assist devices. This research is designed to provide a tool that can be used to investigate the

flow of blood through a ventricular assist device. This unique insight into the internal fluid structures will lead to improved artificial devices capable of sustaining human life.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

During FY94, the baseline design by the NASA Johnson Space Center CISC) and Baylor College of Medicine (BCOM) was

simulated using an Ames-developed CFD tool. An inducer, developed from the Shuttle engine, was introduced in front of the

impeller. The new configuration was clinically tested at BCOM and showed a drastic reduction in red blood cell damage. A

parametric study is being performed to optimize the impeller blade shape and the tip clearance.

Planned future work

To further modify the design to remove trouble areas and to support clinical experiments. The present configuration

still causes blood clotting in the bearing region and near the tip of the inducer and flow straightener. By the end of the

second year of this DDF effort, we plan to finalize the design so that clinical experiments on animals can be successfully

completed.

Prepared by Dochan Kwak Org. Code ADC M/S T27B-1 Phone (415) 604-6743

95
N/LRA

Ames Research Center

Fiscal Year 1994

Director's Discretionary Fund Report

Title of Investigation A Study of Atmospheric Sampling by Supersonic Aircraft

Investigator(s) (show affiliation) Stephen R. Langhoff, Ames Research Center, Moffett Field, CA 94035-1000;

Henry G. Adelman, Thermosciences Institute, Ames Research Center

Funding Year Initiated FY94 Expected completion date FY95

Total priorto FY94 Authorized in F-Y94 $40,000

Total expended in FY94: $40,000 (Estimated) Requested for FY95, ifany _K)s000

In-house

Contracts (identify) $40,000 (Thermosciences Institute)

Grants (identify)

Status of study [] Completed in FY94

If continued in FY95 _ with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

The purpose of the investigation is to study the feasibility of using supersonic aircraft to obtain atmospheric

samples for ozone depletion analyses. The possibility of changes in the sample composition due to passage through the

aircraft shock waves is being examined. A reaction mechanism for the sample species has been developed for certain

nitrogen and chlorine compounds. Thermochemical species data have been calculated using computational chemistry

methods. These data and the reaction mechanisms are used in a reacting flow model to determine sample changes.

F'Y94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

A European aerospace community proposal to utilize Concorde aircraft to obtain samples was analyzed. It was

concluded that certain nitrogen and chlorine compound information could be obtained at Mach 2.

Planned future work

In the future, the thermochemical data and reaction mechanism wig be extended to include more species. If the

sample heating is too severe to permit chemical integrity, then the possibility of sampling from the cold leeward side

of a fiat plate inclined to the flow will be examined.

Prepared by Henry Adelman Org. Code STC M/S 230-3 Phone (415) 604-5056

96
Fiscal Year 1994

Ames Research Center Director's Discretionary Fund Report

Title of Investigation Formation of Organic Matter from Carbon Dissolved in Minerals

Investigator(s) (show affiliation) Narcinda Lerner, Ames Research Center, Moffett Field, CA 94035-1000;

Friedemarm Freund, SETI Institute, Ames Research Center

Funding Year Initiated FY94

Total prior to FY94

Total expended in FY94: (Estimated)

In-house $5,000

Contracts (identify)

Grants (identify) $35,000 SETI Cooperative Agreement NCC 2-572

Expected completion date FY95

Authorized in FY94 $40r000

Requested for FY95, if any $40,000

Status of study [] Completed in FY94

If continued in FY95 [] withfunds remaining?

Iftransitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

Before life could start on Earth, there must have existed a reservoir of abiotically formed organic matter from which

the first organisms evolved. Many gas-phase, liquid-phase and gas/liquid-solid mechanisms have been studied in the

past leading to organics. However, no definite success has been reported. This work is initiated to test the fundamentally new proposition that a mechanism for the synthesis of complex organic molecules may occur inside magmatic

minerals. The only ingredients needed are I_O and CO 2 dissolved in the mineral matrix during crystallization at high

temperatures and pressures and exsolved during cooling and decompression. Recent studies on model systems have

demonstrated that dissolved 1-t20 (and probably CO2) undergo a redox conversion inside the mineral matrix forming H 2

(and reduced C) plus peroxy. During exsolution I-I2 and reduced C are predicted to interact with each other at major

lattice defects such as dislocations and subgrain boundaries. They are expected to form protomolecular entities of the

general kind (HxCyOz) n-, which would yield organic molecules upon acid dissolution or weathering.

FY94 applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

A carbon arc fusion furnace has been set up to prepare for the growth of crystals in the presence of isotopically labeled

D20 and t3CO2. Total Organic Carbon (TOC) analyses have been performed on large MgO crystals grown earlier and TOC

concentrations up to 55 ppm have been found. Gases evolved during crushing in vacuum or in N 2 have been collected and

analyzed by gas chromatography and mass spectroscopy (GC-MS). A novel wet-chemical analytical procedure for determining peroxy in minerals has been developed and tested.

Lerner, Narcinda, and Freund, Friedmarm: Organic Matter Supplied to a Planet by Tectonic and Volcanic Activity. Paper

presented at the International Conference on Habitable Zones, Ames Research Center, Jan. 1994.

Planned future work

To perfect the growth of crystals in the carbon arc furnace to the point that it becomes feasible to use isotopically

labeled gases. To continue to improve the TOC and peroxy analyses. To further develop the crushing plus gas collection

experiments and to extend them to sample preparation under reactive and/or isotopically labeled gases. To develop

techniques to analyze by GC-MS any oxygenated organic molecules from acid solutions.

Prepared by Friedemann Freund Org. Code SSX M/S 239-4 Phone (415) 604-5183

97
Ames Research Center

Fiscal Year 1994

Director's Discretionary Fund Report

Title of Investigation Surface Shear Stress Measurement Using Liquid Crystal Polymers

Investigator(s) (show affiliation) B.G. McLach]an and J. H. Bell, Ames Research Center, Moffett Field, CA 94035-1000;

M. L. Brandes and M. Goutennan, University of Washington, Seattle, WA 98195

Funding Year Initiated FY93 Expected completion date

Total prior to FY94 $40,000 Authorized in FY94 $40t000

Total expended in FY94:$36,000 (Estimated) Requested for FY95, if any

In-house $20,000

Contracts (identify) $16,000 (M. Gouterman, University of Washington)

Grants (identily)

Status of study [] Completed in FY94

If continued in F'Y95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] with F'Y95 funds?

to Other (identify)

Purpose of investigation

Assess the feasibility of liquid crystal polymer film coatings for surface shear stress field measurement in

aerodynamic testing.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Report in preparation.

Planned future work

Studies will continue, culminating in evaluation tests of technology in wind tunnel environment.

Prepared by B.G. McLachlan Org. Code ADD M/S 227-2 Phone (415) 604-0944

98
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation Impacts of Automated Differentiation on Numerical Design Optimiztion

Investigator(s) (show affiliation) Hirokazu Miura, Ames Research Center, Moffett Field, CA 94035-1000;

llan Kroo and Steve Altus, Stanford University, Pale Alto, CA 94305

Funding Year Initiated _'Y94

Total prior to FY94

Total expended in FY94:

In-house $11,740

Contracts (identify)

Grants (identify) $26,000

(Estimated)

Expected completion date FY96

Authorized in FY94 $40r000

Requested for FY95, if any $40r000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?.)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

Aircraft design is a highly complex nonhierarchical process with intricate interactions among disciplines. We are

trying to find a hierarchical program architecture that is amenable to parallel computation on multiple workstations on

a local network. At least two approaches are used to decompose the system of discipline modules into independent

"circuits." Approaches that implement the basic concept of collaborative design will be worked out and tested.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Two types of program architecture were tested and one architecture was made operational for design optimization

performed on three workstations on a local network at Stanford University.

Kroo, I.; AItus, S.; Braun, R.; Gage, P.; and Sobieski, I.: Mu]tidisciplinary Optimization Methods for Aircraft Preliminary Design. AIAA-94-4325-CP, presented at 5th AIAA/NASA/USAF/ISSMO Symposium on Multidiscipinary

Analysis and Optimization, Panama Beach, Fla., Sept. 7-9, 1994.

Planned future work

An additional powerful workstation will be added to the network to work with more demanding numerical

calculations, such as panel codes for aerodynamic analysis. Investigation of the performance of the collaborated design

scheme will be continued to clarify the issues associated with the overall system performance. Generic characteristics

of the new architecture will be identified for possible applications to disciplines other than aircraft design.

Prepared by Hirokazu Miura Org. Code APS M/S 237-11 Phone (415) 604-5888

99
Fiscal Year 1994

Ames Research Center Director's Discretionary Fund Report

Title of Investigation The Opacity of Water Vapor

Investigator(s) (show affiliation) Harry Partridge and David Schwenke, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY94

Total prior to FY94

Total expended in FY94:$40,000

In-house $40,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY95

Authorized in F-Y94 $40,000

Requested for F'Y95, ifany $40,000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in F"Y95

[] with FY95 funds?

toOther(idenlify)

Purpose of investigation

The purpose of this research is to determine accurate opacities for hot water vapor, which are required for modeling the atmospheres of oxygen-rich cool evolved stars. Specifically, we plan to 1) determine an accurate dipole moment

surface for water; 2) develop a hybrid potential energy surface for water using the accurate experimental potential near

the equilibrium geometry and the ab initio results for highly distorted geometries; and 3) determine the ro-vibrational

energy levels and their intensities for all levels that are significantly populated at stellar temperatures.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

None

Planned future work

The second year we will concentrate on using the potential energy and dipole moment surfaces generated in the

first year of the study to determine the ro-vibrational energy levels and intensities. These will be incorporated into

opacity models used to study oxygen-rich cool evolved stars.

Prepared by Harry Partrid_;e " . Org. Code STC M/S 230-3 Phone (415) 604-5236

100
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation An Ultralow-Temperature Thin-Film Thermometer

Investigator(s) (show affiliation) Pat R. Roach, Ames Research Center, Moffett Field, CA 94035-1000;

A1 Spivak and Mic Clark, Trans-Bay Electronics, Inc., Ames Research Center

Funding Year Initiated FY93 Expected completion date _I_'gS

Total priorto F-Y94 _38.000 Authorized in F'Y94 $38.000

Total expended in FY94: (Estimated) Requested for F-Y95, if any

In-house $8,000

Contracts (identify) $30,000 (to Trans-Bay Electronics for support service personnel)

Grants (identify)

Status of study [] Completed in FY94

If continued in F'Y95 _ with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

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.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

A set of thin-film thermometers has been fabricated according to the requirements set forth in the proposal. These

are tiny gold-aluminum superconducting alloy films on sapphire substrates. They have been checked at room temperature, 77 K, and 4.2 K.

Planned future work

Our low-temperature cooler will measure the thermometers in their operating range below 0.38 K when it becomes

operational, which should be soon.

Prepared by Pat R. Roach Org. Code SFT M/S 244-10 Phone (415) 604-3191

lOl
Ames Research Center

Fiscal Year 1994

Director's Discretionary Fund Report

Title of Investigation Deep Near-lnfrared Cosmological Surveys

Investigator(s) (show affiliation)

Thomas L. RoeUig and Edwin F. Erickson, Ames Research Center, Moffett Field, CA

94035-1000; Jacqueline A. Davidson, SETI Institute, Ames Research Center; Arati Chokshi,

Infrared Processing and Analysis Center and The Indian Centre for Astrophysics,

California Institute of Technology, Pasadena, CA 91125

Funding Year Initiated "_FY94

Total priorto FY94

Total expended in FY94:

In-house $39,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date Fyc)5

Authorized in FY94 _39,000

Requested for F"Y95, if any _0,000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other funding, to RTOP (number?)

to Program (name?)

I_ Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

Imaging measurements of distant galaxies can serve as an excellent probe of the space-time curvature of the

universe if galaxies are uniformly distributed throughout space on a sufficiently large scale. Therefore, measurements

of distant galaxies can help answer one of the most important questions in cosmology: whether the universe is open

and will continue expanding forever, or closed, in which case it will eventually stop expanding and instead collapse

again in a "Big-Crunch." In this investigation we study the effectiveness of very sensitive near-infrared imaging for

studying the cosmology of distant galaxies.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

None

Planned future work

This past year we have made good progress in modeling the expected results of a dedicated near-infrared space

mission to determine the value of omega in cosmology. In the next fiscal year we plan to extend on this effort, adding

the effects of source confusion in the near-infrared images. We also plan to remove certain systematic anomalies that

we have detected in our analysis as well as set constraints on the minimum mission size that will be needed to acquire

the necessary data.

Prepared by Thomas Roellig Org. Code SSA M/S 245-6 Phone (415) 604-6426

102
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation Utility of the Experimental Electro-Optical Camera (SPEC-T) for Assessment of Insect/Drought

Related Forest Mortality

Gary A. Shelton and Vincent G. Ambrosia, Ames Research Center, Moffett Field,

Investigator(s) (show affiliation) CA 94035-1000; James McKean, U.S.D.A. Forest Service, Pleasant Hill, CA 94523;

Funding Year Initiated

Total prior to FY94

Total expended in FY94:$40,000

In-house

Contracts (identify) NAS2-13712

Grants (identify)

John C. Arveson, Ames Research Center; Edward A. Hildum, SVERDRUP, Ames Research

Center; Jeffrey S. Myers, ATAC, Inc., Ames Research Center

FY93 Expected completion date FY95

Authorized in FY94 $40.000

(Estimated) Requested for FYgS, if any _40,000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If Iransitioned to other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

Evaluate the application of a newly developed, high spatial resolution, electro-optical digital camera system

(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 instruments.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

Instrument flown sucessfully on multiple missions. Initial assessment of data presented in paper.

Ambrosia, V. G.; and McKeen, J.: Utility of the Electro-Optical Camera (SPEC-T) for Assessment of Insect/Drought

Related Forest Mortality. Paper presented at the Fifth Biennial Conference on Remote Sensing Applications in the

Forest Service, Portland, Ore., Apr. 1994.

Planned future work

Analysis of the 25 August 1994 data set collected over the primary study site. This activity will occur and conclude

in FY95.

Prepared by Vincent G. Ambrosia Org. Code SGE M/S 242-4 Phone (415) 604-6565

103
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation Development of 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 Initialed FY93 Expected completion date FY95

Total priorto FY94 _,40,000 Authorized in FY94 _0_000

Total expended in FY94: (Estimated) Requested for F'Y95, if any

In-house $10,100

Contracts (identify) $15,000 with University of Colorado

Grants (identify)

Status of study [] Completed in FY94

If continued in FY95 [] withfunds remaining?

If transitionedto other funding, to RTOP (number?.)

to Program (name?)

[] Continued in F'Y95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

This remote sensing project is developing a new theory and measurement method for an emerging remote sensing

technology---canopy architecture remote sensing--that will supplement the existing optical and microwave remote

sensing technologies.

FY94 applications of results, patents, reports/publications,papers at meetings, any awards received, etc.

None

Planned future work

We will complete the work originally planned for the second year of the project: 1) The engineering model of the

plant canopy structure sensor will be completed; 2) the remaining parts of the prototype system will be ordered; and

3) the prototype system will be assembled and tested on plants cultivated in a growth chamber that is part of the controlled ecological life support systems (CELSS) project.

Prepared by V.C. Vanderbilt Org. Code SCE M/S 242-4 Phone (415) 604-4254

104
Fiscal Year 1994

AmesResearchCenter Director's Discretionary Fund Report

Title of Investigation Technology Utilization of Adaptive Structures in Active Electronic Equipment Isolation

Investigator(s) (show affiliation) David F. Voracek, Dryden Flight Research Center, Edwards, CA 93523-0273

Funding Year Initiated FY94

Total prior to FY94

Total expended in FY94:$40,000

In-house $30,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY95

Authorized in FY94 :_d),000

Requested for FY95, if any $40,000

$10,000 California Polytechnic State University

Status of study [] Completed in F'Y94

If continued in F-Y95 [] with funds remaining?

If transitionedto other funding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other (identify)

Purpose of investigation

This research is directed at the development of an active isolation system for aircraft electronic equipment. The

research will utilize adaptive structures such as piezoelectrics in its active isolation system design. The goal of the two

year program is to design and flight test an active isolation system for the electronic equipment to protect it from the

harsh aircraft environment.

FY94 applications of results, patenfs, reports/publications,papers at meetings, any awards received, etc.

The first year of the research has resulted in several conceptual designs of an active isolation system. A demonstrator

configuration has been developed and is currently in testing. Several other experiments have been done using piezoelectrics

in active damping control systems. A demonstration of the damping capabilities of the piezoelectrics has been shown on a

model glider. An aluminum wing was designed and piezoelectrics were used to damp out the first wing bending.

Planned future work

The planned future work includes fabricating a flight test demonstration of the active isolation system; this task

includes final design, control law development, and flight test of the system.

Prepared by David F. Voracek Org. Code XRDV M/S 4840-D Phone (805) 258-2463

105
Fiscal Year 1994

Ames Research Center Director's Discretionary Fund Report

Title of Investigation Does the Collapse of Diatom Blooms Trigger Coccolithophore Blooms?

Investigator(s) (show affiliation) Robert Wrigley and Lynn Rothschild, Ames Research Center, Moffett Field, CA 94035-1000

Funding Year Initiated FY94

Total priorto FY94

Total expended in FY94:$40,000

In-house $40,000

Contracts (identify)

Grants (identify)

(Estimated)

Expected completion date FY95

Authorized in FY94 $401000

Requested for FY95, ifany $40,000

Status of study [] Completed in FY94

If continued in FY95 [] with funds remaining?

If transitioned to other tunding, to RTOP (number?)

to Program (name?)

[] Continued in FY95

[] with FY95 funds?

to Other 0dentify)

Purpose of investigation

The purpose of this investigation is to determine if there is a causal relationship between the end of a diatom bloom

and the beginning of an Emiliania bloom, and if so, what its chemical basis is. The ultimate objective is to predict the

onset of Emiliania blooms to better monitor them by remote sensing. Our data may suggest ways to alter the global

carbon cycle by triggering or suppressing Emiliania blooms.

F-Y94applications of results, patents, reports/publications, papers at meetings, any awards received, etc.

Rothschild, L. J. :CO2 and Diatom Mats. Nature, vo1..368, 1994, p. 817.

Planned future work

During this fiscal year, we will stabilize the cultures, grow the diatoms in the saltwater medium, and grow the

Emiliania in the diatom-conditioned and unconditioned medium. If there are differences in growth of the Emiliania

between the two media, we will send the media to a commercial lab for chemical analysis.

Prepared by Lynn Rothschild Org. Cede SGE M/S 239-12 Phone (415) 604-6525

106
Form Approved

REPORT DOCUMENTATION PAGE oMBNo 0704-0188

Public reportingburdenfor thiscollectionof informationiS eslimated to average 1 hourpar response, includingthe time for reviewing instructions,searchingexisting data sources,

gatheringand maintainingthe data needed, and completingand reviewingthe collection of information, Send comments regarding1his burdenestimate or any other aspect of this

collectionof information, includingsuggestionsfor reducingthisburden, to WashingtonHeadquartersServices, Directoratefor informationOperations and Reports, 1215 Jeffemon

Davis Highway,Suite 1204, Arlington,VA 22202-4302, and to the Office of Managementand Budget,PaperworkReductionProject {0704-0188), Washington, DC 20503,

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE

February 1995

1

4. TITLE AND SUBTITLE

Director's Discretionary Fund Report for Fiscal Year 1994

i6. 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

3. REPORT TYPE AND DATES COVERED

Technical Memorandum, Fiscal Year 1994

5. FUNDING NUMBERS

307-51-50

8. PERFORMING ORGANIZATION

REPORT NUMBER

A-94135

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

NASA TM- 108848

11. SUPPLEMENTARY NOTES

Point of Contact: John T. Howe, Ames Research Center, MS 200-16, Moffett Field, CA 94035-1000

(415) 604-5500

12s. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified-Unlimited

Subject Category - 99

12b. DISTRIBUTION CODE

13. 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 1994 (October 1993 through September 1994). An appendix provides administrative information for each of the sponsored research programs.

jL

14. SUBJECT TERMS

Director's Discretionary Fund, Space science, Life science, Aeronautics,

Space and terrestrial applications

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION

OF REPORT OF THIS PAGE

Unclassified Unclassified

NSN 7540-01-280-5500

19. SECURITY CLASSIFICATION

OF ABSTRACT

IS. NUMBER OF PAGES

112

16. PRICE CODE

A06

20. LIMITATION OF ABSTRACl

Standard Form 298 (Rev. 2-B9)

Prescribed by ANSI Sld. Z39-1B

298-102