Physical Sciences Division
Weekly Highlights for Week Ending 4/25/2002
*** Indicates item is appropriate for the HQ senior staff and may appear on the OBPR Web site: http://spaceresearch.nasa.gov
EDUCATION and OUTREACH
THE PREVENT BLINDNESS AMERICA (Ohio) VISITS NASA GLENN VISION RESEARCH LAB: The Prevent Blindness America (PBA Ohio) visited NASA GRC's lab pioneering the development of novel probes for detecting and preventing eye diseases, on April 17th. The team included Sherry Williams (President & CEO), Rick Bunner, PBA Ohio Board Chair (Ohio Department of Health), and Carrie Glaeden, PBO Board Member (Deputy Counsel, Gov. Taft's Office). They spent close to one hour and thirty minutes with Dr. Rafat Ansari (GRC) in the lab and were quite impressed with the vision research program. Later in the evening Dr. Ansari attended the PBA's People of Vision Annual Awards Dinner as guest of Sherry Williams. Before dinner Dr. Ansari was introduced to Governor Bob Taft by his Deputy Counsel Carrie Glaeden. She briefed the Governor about her visit to the GRC lab on eye related research work. The Governor spoke with Dr. Ansari and said that he is very pleased to hear that such important work is going on at NASA GRC and that he has been working hard with people in Washington restoring GRC funding. The Governor asked Carrie to let Governor's Scientific Advisor know about this work.
EDUCATIONAL OUTREACH: At the request of Dennis Christopher, an educational specialist working at NASA GSFC and Dr. Robert Lipton from Pennsylvania State University, John McQuillen and Dennis Stocker of NASA Glenn conducted a ViTS for 45 students and their teachers from the Berks County Schools on Monday, April 22. The title for the conference was Microgravity and included a discussion of Newton's Laws, demonstrations with the mini-drop tower and the water balloon video.
SHUTTLE FLIGHT PROGRAM
MECHANICS OF GRANULAR MATERIALS (MGM III): The University of Colorado in Boulder (UCB) MGM team has begun the assembly of the flight test cells. The assembly process will take approximately one month, after which four test cells will be monitored for an additional month to mitigate any "infant mortality" concerns. The test cells will be transported to the Spacehab Payload Processing Facility (SPPF) approximately three weeks before launch, and then final inspections, selection of the three flight test cells, and turnover will occur, with installation following at L-14 days. In addition, MGM personnel completed an accumulator exercise procedure on the Twin Double Locker Assembly (TDLA) in mid-April. The next (and final planned) accumulator exercise will take place at the time of the Orbiter IVT currently scheduled for late May/early June.
ISS FLIGHT PROGRAM
MICROGRAVITY RESEARCH PROGRAM OFFICE (MRPO) PAYLOAD OPERATIONS STATUS ON THE INTERNATIONAL SPACE STATION (ISS) 8A STAGE: We have completed Week #18 of Increment 4 and have entered into Week#19. STS-110 has returned to Earth and the 8A stage has began in earnest. All MRPO payloads are functioning nominally except for one of the two acceleration measurement systems (SAMS). Troubleshooting for this payload is in progress. We now have experiments on board dealing with protein crystal growth, bioprocessing and zeolite crystal growth (ZCG). ZCG was activated today and is the first payload to require and receive active vibration isolation during the growth period.
MACROMOLECULAR CRYSTALLIZATION EXPERIMENTS LAUNCHED ON STS-110: The Enhanced Gaseous Nitrogen (EGN) Dewar was launched on STS-110 for a projected 60-day mission on the International Space Station (ISS). The payload contained 351 samples of proteins prepared for liquid-liquid diffusion-based crystallizations. Crystallization samples were loaded into plastic capillaries by the Principal Investigator's team, students participating in the program, "Student Access to Space", and investigators at MSFC. It is noteworthy that this is the fourth EGN flight to the ISS, where results from analyses of samples returned from previous EGN flights have recently been reported. These reports compile notable progress in resolution of technical problems and improvements in crystal quality and size, depending on the specific protein.
***SCIENCE UNFOLDS SHAPES OF LIFE: Fluid Physics Investigator's Research Reported in Times Higher Education Supplement (a publication of the Times of London 4/12/02).
The workings of life are bound up in the intricate folds of the long-chain polymers known as proteins. Yet science has been unable to predict how each one should shape up, writes Steve Farrar. Now a team of physicists believe they have found an approach that could lead to an understanding of the ground rules of the origami of nature. The human body has hundreds of thousands of different varieties of these remarkable molecules, which make up every living cell. Following a genetic recipe, each is built from a unique chain of tens of hundreds of amino acids. The properties and functions of each protein are determined by its folded shape, and this is ultimately determined by the properties of the component amino acids. But this formula has proved highly resistant to science. Jayanth Banavar, professor of physics at Pennsylvania State University in the United States, and Amos Maritan, professor of physics at the International School for Advanced Studies, in Trieste, Italy, have led an effort to attack the problem. They suggest that polymer chains - including proteins - should be thought of as tubes rather than as strings of beads as they have been previously. This changes the basic mathematics of the model. Professor Banavar said that when the tube was tuned to be comparable to the scale at which component amino acids reacted with their surroundings, many well-known characteristics emerged. The model molecules naturally fold themselves into a familiar repertoire of helices, hairpins and sheets - just as is observed. They also possess the flexibility and versatility essential to their central role in life.
"It is an extremely simple idea that leads to a novel phase of matter that's tailor-made for nature to use for proteins," Professor Banavar said. The results are published in the journal Proteins : Structure, Function and Genetics:
This item appears in the Research Update section of spaceresearch.nasa.gov
EXTINCTION OF LOW STRAIN RATE DIFFUSION FLAMES BY AN AGENT IN MICROGRAVITY: The objective of this investigation, led by Anthony Hamins of NIST, is to better understand the effect of fire suppressants on low-strain-rate diffusion flames, such as those that might occur in orbiting space platforms. Earlier work on the determination of Planck mean absorption coefficients for HBr, HCl, and HF to help better understan the role of radiation appeared in the Journal of Heat Transfer (ASME J. Heat Transfer, 124, 26-30, 2002. More recent studies have focused on flame extinction measurements using nitrogen in the fuel stream of counterflowing methane-air diffusion flames were successfully conducted in the 2.2-sec drop tower at GRC. In parallel, a measurement technique was developed in normal gravity and used in the 2.2-sec drop tower to determine the temperature profile in the high temperature reaction zone of near-extinction counterflowing methane/air flames. The radiative energy emitted from a thin SiC filament (10 mm to 15 mm diameter) placed along the axial centerline of the flame was digitally recorded using a CCD camera with a close-up lens. Because the spectral response curve of the detection system is not constant, a linear relationship between the detector signal and T4 cannot be assumed. To find the relationship between signal intensity and filament temperature, the temperature profiles were calibrated using the OPDIF computer model. Thermocouple measurements were attempted, but were found to perturb the weak flames. The measurements demonstrated interesting differences between the temperature profiles in 1-g and m-g.
FORMATION OF CARBON NANOTUBES IN A MICROGRAVITY ENVIRONMENT: This research, conducted by John Alford (TDA Research Inc.), investigates the effect of buoyancy on the formation and morphology (size and length) of single-walled carbon nanotubes and will possibly lead to production of superior (longer) nanotubes. The hypothesis of the work is that by eliminating buoyancy effects from the formation process of Single Walled NanoTubes (SWNT) greater production and manufacturing yields can be obtained. Single-walled carbon nanotubes represent the ultimate high strength carbon fiber and could revolutionize future aerospace structures and hence aircraft and spacecraft designs of the future. This research may also benefit other fields including biosensors and electrical devices such as semi-conductors.
Even though nanotube science has become one of the worlds most rapidly advancing areas of research, very little is known about the processes involved in nanotube synthesis. To study the formation of carbon nanotubes in an environment unhindered by the buoyancy-induced flows generated by the high temperatures necessary to vaporize carbon and grow nanotubes, a miniature arc discharge reactor has been developed and demonstrated in NASA Glenn's 2.2-second drop tower. Progress to date includes demonstration experiments in the 2.2-second drop tower and verification with TEM and SEM that nanotubes can be formed in microgravity. Efforts are now underway to improve the arc discharge process to promote favorable time scales for nanotube formation in microgravity. The efforts so far have shown that short duration energy dissipation inside the carbon rod results in short, stunted carbon nanotubes.
SECONDARY MOTION IN CONVECTION LAYERS: Fluid Physics PIs Drs. Cho Lik Chan and C. F. Chen are studying the three-dimensional motion in convection cells generated by sideways heating of a solute gradient by experiments and linear stability analysis. In the experiments, they obtained visualizations and PIV measurements of the velocity of the fluid motion in the longitudinal plane perpendicular to the imposed temperature gradient. The flow consists of a horizontal row of counter-rotating vortices within each convection cell. The magnitude of this secondary motion is approximately one-half that of the primary convection cell. Results of a linear stability analysis of a parallel double-diffusive flow model of the actual flow show that the instability is in the salt-finger mode under the experimental conditions. The perturbation streamlines in the longitudinal plane at onset consist of a horizontal row of counter-rotating vortices similar to those observed in the experiments. Details of this work were recently published in Journal of Fluid Mechanics 455, pp. 1-19 (2002).
Additional meetings and symposia can be found at: http://microgravity.grc.nasa.gov/ugml/ugmltext.htm
The MRPO Program Calendar can be found at:
April 22-25 2002 Applied Computational Research Society Joint Meeting: Computational Micro- And Nano-Technology, International Conference on Computational Nano Science, Modeling & Simulation of Microsystems, San Juan Marriott Resort, San Juan, Puerto Rico, http://www.cr.org
April 26, 2002, Science Concept Review & Requirements Definition Reviews for the First LTMPF Flight (M1) Co-experiments COEX and CQ, Embassy Suites Hotel, Monrovia, CA
May 9-11, 2002, Fundamental Physics Investigator Workshop, Laguna Cliffs Marriott Resort, Dana Point, CA, http://funphysics.jpl.nasa.gov/conference-02/index.html
May 19-24, 2002, Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science (QELS), Long Beach Convention Center, Long Beach, California
May 29-June 1, 2002, Division of Atomic, Molecular and Optical Physics Annual Meeting
Williamsburg, Virginia, http://www.aps.org/meet/DAMOP02