Code UG Weekly Notes 10-18-01

Physical Sciences Division
Weekly Highlights for Week Ending 10/18/2001

*** Indicates item is appropriate for the HQ senior staff and may appear
on the OBPR Web site: http://spaceresearch.nasa.gov

GENERAL

FLUID PHYSICS PI ELECTED FELLOW OF THE AMERICAN PHYSICAL SOCIETY: Prof.
John Goree of the University of Iowa was elected a fellow of the American
Physical Society in September. He is the PI on a fluid physics grant entitled
"Plasma Dust Crystallization" which includes both ground-based
experiments and collaboration with German and Russian researchers on sounding
rocket experiments and the Plasma Krystall Experiment (PKE) currently
being conducted aboard the ISS in the Russian Service Module. In addition,
he is chairman of the International Advisory Board for International Microgravity
Plasma Facility (IMPF) being planned for the ISS. A dusty plasma is an
ionized gas containing micron-scale charged particles. Dusty plasma research
is a rapidly growing field with applications ranging from fundamental
studies of freezing and melting phase transitions to the formation of
stars to the control of contamination in the processing of semiconductor
devices.

SHUTTLE FLIGHT PROGRAM

MECHANICS OF GRANULAR MATERIALS (MGM): MGM hands-on training for the
STS-107 crew was held 9/26/01 at the University of Colorado at Boulder.
The training was attended by Mark Lankton, Susan Batiste, Tawnya Ferbiak,
Lora Keiser, and six crew members: Rick Husband, William McCool, Michael
Anderson, Kalpana Chawla, Laurel Clark, and Ilan Ramon. Husband, McCool,
Clark, and Ramon received a familiarization briefing, a tour of the Laboratories
for Atmospheric and Space Physics (LASP), and observed hands-on training.
Anderson and Chawla concentrated on hands-on training, performing two
test runs, and implementing both nominal and alternate procedures. The
crew performed all procedures to prepare for the case that uplink commanding
is not available. Flight hardware was used for training and performed
nominally. Redlines to the procedures were few and minor in nature. Overall,
training was successful.

ISS FLIGHT PROGRAM

PHYSICS OF COLLOIDS IN SPACE (PCS) ON ISS: During EXPPCS’ 84 hours of
operations over the last week, investigations continued on the Colloid-Polymer
Gel sample, mostly directed toward studying its aging. Also, the Colloidal
Glass sample was remixed and a 96 hour run initiated to capture the early
stages of crystallization in this sample. In addition, the AB6 and AB13
binary samples continue to be monitored for changes or further evolution.

DELTA-L CRITICAL DESIGN REVIEW (CDR) PRE-BOARD: A Marshall Space Flight
Center (MSFC) Pre-Board meeting was conducted during the week of October
1, 2001 to review the CDR results and findings of Delta-L, which is an
MSFC in-house development for a Biotechnology Protein Crystal Growth Investigation
to be conducted in the Microgravity Science Glovebox (MSG). The Pre-Board
concluded that the review had been adequately conducted, that there were
no unresolved issues to carry forward to a formal Board review, and their
recommendation was to proceed with the build of the flight hardware.

SCIENCE HIGHLIGHTS

BIOTECHNOLOGY:

TALK PRESENTED AT INSTITUTE FOR CRYSTAL GROWTH: On 9/17/2001, Dr. Witold
Palosz of Universities Space Research Association (USRA) visited the Institute
for Crystal Growth (Berlin, Germany) and gave a talk, entitled "Growth
of Bulk Crystals From the Vapor – the Technique of the Past or of the
Future?"

COMBUSTION SCIENCE:

GRAVITATIONAL EFFECTS ON PARTIALLY-PREMIXED FLAMES: The objective of
the research, led by Prof. I. Puri of University of Illinois at Chicago,
is to investigate the effects of gravity on the structure and stability
of hydrogen-, methane-, and propane-air flames under partially premixed
conditions by employing both numerical and experimental techniques. The
design and fabrication of the experimental rig for drop tower experiments
has recently been completed, the safety permit is obtained and initial
experiments has initiated. Optical paths for future implementation of
other diagnostics such as holography have been tried out. Towards the
investigation of the relative importance of advection and diffusion fluxes
on partially premixed flames, the structure of unsteady has been examined,
focusing on the interactions between the reaction zones. The 1-g flame
is inherently unsteady due to the competing effects of buoyancy and flow
dilatation. For the 1-g case, in the absence of co-flow, buoyancy tends
to dominate dilatation, pushing the outer non-premixed flame closer to
the inner premixed flame and thereby enhancing the interactions between
the two zones. In terms of the modified mixture fraction Z, the rich premixed
reaction zone lies between 0.72 < Z < 0.8, whereas the nonpremixed
zones lie between 0.47 < Z < 0.55. Although the 1- and 0-g flames
have markedly different spatio-temporal characteristics, the temperature,
as well as the major and minor species profiles, follow similar state
relationships in terms of Z for the two flames. Thus, an important observation
is that the modified mixture fraction is effective in characterizing the
structure of both steady and unsteady partially premixed flames.

INVESTIGATION OF LIFTOFF AND BLOWOUT OF TRANSITIONAL AND TURBULENT JET
FLAMES: This research is being led by Prof. J. Riley at the University
of Washington. The problems of turbulent jet flame liftoff and blowout
are of critical importance to the safety and reliability of a variety
of combustion devices. Competing theories focusing on both premixed and
non-premixed flame-like behavior at the base of the flame have been proposed.
The examination of recent glovebox flight data suggests the hypothesis
that gravity influences flame stabilization and extinction through the
role buoyancy plays in transition to turbulence. This investigation proposes
applying three-dimensional direct numerical simulation and concurrent
theoretical analysis to (1) test this and other hypothesis, (2) identify
the governing mechanisms for liftoff and blowout, (3) determine which
of the various modeling approaches are most consistent with the governing
mechanisms, and (4) devise means for controlling liftoff and blowout.
A series of simulations of a laminar, lifted jet have been initiated recently.
Also, an algorithm to solve the linear stability equations for buoyant,
laminar, reacting jets has been developed. The lifted flame has been obtained
by first choosing a parameter range (in terms of Reynolds, Damkohler,
and Schmidt numbers) in which it was thought that the flame would lift.
The simulation has then been started with the species in the computational
domain in chemical equilibrium. Some experiments have also been initiated
on the effects of the Damkohler number, Reynolds number, and initial perturbations
on jet liftoff. It is seen that increasing the Reynolds number increases
the jet liftoff height, as expected. The liftoff height occurs where there
is an approximate balance between the advection speed of the jet and the
laminar flame speed.

FLUID PHYSICS:

FLUID PHYSICS PIs PLAY KEY ROLE IN INTERDISCIPLINARY INTERNATIONAL CONFERENCE:
Fluid Physics PI Prof. V.K. Dhir (UCLA) co-chaired the Microgravity Transport
Processes in Fluid, Thermal, Materials, and Biological Sciences II September
30 – October 5, 2001 Banff Center for Conferences. In addition fluid physics
PI Dr. R. Balasubramaniam (NCMRFC/GRC) served on the conference scientific
committee; Prof. Bankoff (Northwestern), Prof. Gary Leal (UCSB) and Prof.
A. Prosperetti (Johns Hopkins) gave keynote address; and several PIs presented
papers. The main objectives of the conference are to exchange technical
information and ideas among the various scientists and engineers working
in Microgravity Fluid, Thermal, Biological, and Materials Sciences. These
areas have become important to various disciplines within the broader
realm of Microgravity research. The conference addressed the crosscutting
aspects of microgravity science and technology and provide a forum for
the synthesis of knowledge that has been acquired of the last several
years. It effectively covered the growing interdisciplinary aspects of
Microgravity Science and Technology. Details are at: http://www.engfnd.org/1ay.html

ACOUSTIC LEVITATION OF 3-D PARTICLE ARRAYS ACHIEVED: Fluid Physics PI
Prof. R. Apfel (Yale) has successfully demonstrated the levitation of
a quasi 3D array of solid particles in his acoustic levitation system.
This is believed to be the first successful levitation of such a three
dimensional array. Recent modifications to his instrument have allowed
the progression from 2-D to 3-D arrays in which particles are trapped
at pressure nodes in the acoustic field. Arrays containing three layers
of 130-180mm magnesium particles have been levitated. Each layer contains
from 6 to 15 particles with interparticle spacings of about 1.2mm and
spacings of about 1.7mm between layers. This instrument will be used next
to levitate 3-D arrays of liquid droplets in order to study the evaporation
rate of such an array compared to the evaporation of single droplets.

GRAIN INTERACTIONS IN DUSTY PLASMAS STUDIED VIA COMPUTER SIMULATION:
Fluid Physics PI Dr. G. Joyce and Co-I’s at the Naval Research Laboratory
have made a quantitative assessment of the effect of centrifugal potential
barriers on ion trajectories near a grain in a stationary dusty plasma,
which is an ionized gas containing highly charges micron-scale particles.
They have shown that in most situations of interest the barriers are weak
and only marginally affect the validity of the orbital-motion-limited
(OML) theory. The OML theory is then used to show that the electrostatic
interaction between grains is always repulsive. The ion-shadowing force
is calculated and its is shown that this force can lead to a weak net
attraction between grains at long range, under certain conditions with
large grains, dense plasma, and/or low gas pressure. This work was performed
using their Dynamically Shielded Dust (DSD) simulation code, which represents
the grains as dressed particles interacting via the dynamically shielded
Coulomb interaction, which includes wakefields, Landau damping, and collisional
damping. The simulation shows ordering of the grains into rigid strings
aligned with the ion flow, and looser glass-like organization of the strings
in the transverse plane. The presence of strings with odd an even numbers
of grains results in stratification of the grains into planes with an
alternating structure. Dusty plasma research is a rapidly growing field
with applications ranging from fundamental studies of freezing and melting
phase transitions to the formation of stars to the control of contamination
in the processing of semiconductor devices. This work is reported in the
following paper:

"Analytic and Simulation Studies of Dust Grain Interaction and Structuring"
M. Lampe, G. Joyce, and G. Ganguli, Physica Scripta T89 106-111 (2001)

FUNDAMENTAL PHYSICS:

NEW BOOK DESCRIBES COLD ATOMS: Pierre Meystre announces that his new
book "Atom Optics" has just been published at Springer Verlag
(with perfect timing with the Nobel announcement). To Meystre’s knowledge,
this is the first book on this subject. Springer’s description of the
book follows:
"One of the most profound revolutions brought about by quantum mechanics
is that it
does away with the distinction between waves and particles: atoms, in
particular, can
exhibit all the properties that we associate with wave phenomena, such
as diffraction and
interference; it has recently even become possible to prepare collections
of atoms in
coherent states, like those of photons in a laser beam. These developments
are at the
core of the rapidly expanding field of atom optics."
More information can be found on the Springer site,
www.springer-ny.com/detail.tpl?cart=997719093810142&ISBN=0387952748
The book will also have a web-component, which can currently be seen as
a beta-version at www.optics.arizona.edu/aobook

REVIEW ARTICLE PROVIDES DETAILS OF HIGH RESOLUTION THERMOMETERS: Talso
Chui has published a review article on the high resolution thermometers
that have been crucial to the low temperature experiments that are being
flown in Earth orbit. The article describes the history of the HRTs, their
principles of operation, what limits their resolutions, how they have
been applied to make new discoveries, and recent developments toward miniaturization.
The article "SQUID-based high resolution thermometer" by Talso
C. P. Chui can be found in Cryogenics 41, p. 407 (2001).

ARTICLE IN NATURE DESCRIBES NEW PATH TO BOSE-EINSTEIN CONDENSATES IN
HELIUM: Randy Hulet of Rice University recently published a perspective
article in Nature on the recent achievement of BEC in metastable helium:
Randall G. Hulet, "Bose-Einstein condensation: Getting excited about
helium", News and Views, Nature 411, 425 (2001). The articles describes
the reports of two French groups who created samples of excited helium
atoms by electrical discharge, then applied the standard tools for laser
cooling, magnetic trapping, and forced evaporative cooling to produce
the BEC. These processes produce a spin-polarized sample of cold excited
atoms, so the atoms have low probability for ionization by collisions.
The high energy state of the excited atoms provides a BEC with novel properties
and prospects for new applications.

MATERIALS SCIENCE:

CRYSTAL GROWTH OF ZnSe AND RELATED TERNARY COMPOUND SEMICONDUCTORS BY
VAPOR TRANSPORT: A paper, entitled "Band Anticrossing in Highly Mismatched
Compound Semiconductor Alloys," by Kin Man Yu, J. Wu, W. Walukiewicz,
J. W. Ager (Lawrence Berkeley National Laboratory), E. E. Haller (UC Berkeley),
I. Miotkowski, A. Ramdas (Purdue University), and Ching-Hua Su (MSFC),
was presented at the 28th International Symposium on Compound Semiconductors
(ISCS2001), University of Tokyo, Japan, 10/1-4/2001. Photoluminescence
reflection spectroscopy and pressure dependence of optical absorption
spectroscopy in a diamond anvil cell were performed on samples of ZnSeTe
alloys in the entire composition range. On the Te-rich side, the pressure
and the composition dependence of the optical absorption can be well explained
by the band anti-crossing model. On the Se-rich side, the large band gap
reduction observed is a result of an interaction between localized Te
level and the valence band.

UPCOMING EVENTS

Additional meetings and symposia can be found at: http://microgravity.grc.nasa.gov/ugml/ugmltext.htm

October 14-18, 2001, 17th Interdisciplinary Laser Science Conference,
Long Beach Convention Center, Long Beach, CA

October 18, 2001, TeleConference MRT Meeting, 10:00am – 02:00pm CST

November 15, 2001, TeleConference MRT Meeting, 10:00am – 02:00pm CST

December 12-13, 2001, Face-To-Face MRT Meeting, MSFC