From: Microgravity Research Program Office
Posted: Wednesday, June 12, 2002
Physical Sciences Division
Weekly Highlights for Week Ending 6/12/2002
*** Indicates item is appropriate for the HQ senior staff and may appear on the OBPR Web site: http://spaceresearch.nasa.gov
*** NASA AND CLEVELAND BIOMEDICAL RESEARCH LEADERS FORM CONSORTIUM: An agreement among NASA, the Cleveland Clinic Foundation, University Hospitals of Cleveland and Case Western Reserve University was signed on June 7 to establish the John Glenn Biomedical Engineering Consortium. The Consortium also includes the National Center for Microgravity Research on Fluids and Combustion, a partnership between Case Western Reserve University and the Universities Space Research Association. The signing event was covered in local newspapers, radio and television stations and attended by several local dignitaries. Using an integrated, interdisciplinary approach, the Consortium will combine member organizations' unique skills, capabilities, and facilities to achieve common research goals involving human health in space as well as on earth. The research leverages NASA's knowledge and expertise in the areas of fluid physics and sensor technology together with the other Consortium members' world-class capabilities in biomedical research and health care to mitigate risks to astronaut health in long-term space flight. A complete description of the ten initial projects funded through the Consortium is at: http://microgravity.grc.nasa.gov/grcbio/bec.html
IONIZING RADIATION TUTORIAL PRESENTED AT GRC: On June 4, 2002, William X. Culpepper, Chief Engineer in the Avionic Systems Division at NASA JSC, presented a Tutorial on Ionizing Radiation at GRC. Over 120 GRC engineers, scientists and managers attended the day-long session to gather information on the ISS radiation environment, modeling work to date, radiation test programs for experiments, and how to deal with COTS hardware. Mr. Culpepper presented an interesting array of practical tools to be employed to increase the probability of mission success for our hardware development projects.
EDUCATION and OUTREACH
SHUTTLE FLIGHT PROGRAM
ISS FLIGHT PROGRAM
MICROGRAVITY SCIENCE GLOVEBOX (MSG): The Microgravity Science Glovebox was launched aboard STS-111 on 6/05/02. The MSG facility has been successfully transferred from the Multi Purpose Logistics Module and installed into the International Space Station Destiny Module. Initial power-up and checkout of the Facility is scheduled for 7/01/02. Accompanying MSG aboard STS-111 were the first three MSG Investigations: Solidification Using a Baffle in Sealed Ampoules (SUBSA), Toward Understanding Pore Formation and Mobility during Controlled Directional Solidification in a Microgravity Environment Investigation (PFMI), and Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions (InSPACE). The first sample run for the SUBSA Investigation is scheduled for 7/08/02.
CRYSTAL GROWTH AND DESIGN: An article, entitled "Use of Capillaries for Macromolecular Crystallization in a Cryogenic Dewar," has been published in Crystal Growth & Design, 2002, vol. 2 (3), pp.235-238. The authors are Ewa Ciszak, Aaron Hammons, and Young-Soo Hong, Universities Space Research Associates (USRA/SD46). The article describes results of experiments conducted in the Enhanced Gaseous Nitrogen (EGN) Dewar aboard the International Space Station during a 42-day long mission of July/August 2001. The article also presents methods for improvement and further understanding the crystallization processes in the EGN Dewar.
NASA GRC EYE RESEARCH FEATURED IN "REVIEW OF REFRACTIVE SURGERY":
"The need for new diagnostic capabilities to evaluate current refractive surgery outcomes is undeniable. That tools will eventually be developed to measure the laser's power to fundamentally alter the cornea is also unquestioned. But refractive surgeons have had no procedures or technologies to noninvasively and quantitatively monitor the molecular changes that cause corneal abnormalities after laser surgery. Until now. From NASA's Glenn Research Center in Cleveland comes work that has established the experimental basis of dynamic light scattering (DLS) for the early and noninvasive detection of these corneal abnormalities. A diverse group of microgravity scientists, NEI investigators, and aeronautics engineers led by NASA project scientist, Rafat Ansari, PhD, has used a compact fiber-optic system to evaluate the eye at the molecular level. The device was originally designed for experiments in fluid physics on the space shuttle and station; it was created to look at the dynamics of colloids in microgravity environments, pecifically to monitor how protein and synthetic crystals grow in space." Writes Leslie Sabbagh, Editor in Chief of Review of Refractive Surgery in a feature article "Dynamic Light Scattering Focuses On The Cornea- A Molecular Measure Of Clarity". It appeared in the May 2002 issue of the journal.
FLAME-VORTEX INTERACTIONS IMAGED IN MICROGRAVITY: This research, conducted by Prof. J. Driscoll (The University of Michigan), is assessing in microgravity the theory of flame stretch both experimentally and with numerical modeling. This research effort assists in developing physically accurate combustion models to help control pollutant formation in gas turbine aircraft and internal combustion engines. This important endeavor serves to improve the air pollution environment in the nation. The effect of flame stretch, composed of strain and curvature, plays a major role in the propagation of turbulent premixed flames. Although, all forms of stretch (positive and negative) are present in turbulent conditions, little is known about the effect of curvature alone. Recent published results based upon drop tower experiments and computations for inwardly-propagating flames (IPF) and outward-propagating flames (OPF) shown significant differences in the propagation speeds. The Markstein number was used to compare the flame propagation velocity to the unstretched value. The results show the IPF's have significantly higher Markstein numbers than OPF's. The results provide additional evidence that the Markstein numbers associated with strain and curvature have different values.
FAN BEAM EMISSION TOMOGRAPHY (FBET) FOR NON-AXISYMMETRIC LAMINAR FIRES: This research, conducted by Dr. Y. Sivathanu of En'Urga Inc., focuses on the development and demonstration of a technique known as Fan Beam Emission Tomography System (FBET) for use in reduced gravity facilities with combustion experiments. One of the critical issues for the US space program is fire safety of the space station and launch vehicles. A detailed understanding of the combustion phenomenon in reduced gravity environments is therefore essential from a fire safety perspective. The results of this project will allow detailed characterization of a wide variety of fires including non-axisymmetric fires. The method involves a spectroscopic-based scanning technique whereby a 150-nm bandwidth Mid-Infrared spectra is obtained at many locations within the fire. Through spectroscopic reconstruction of the measured spectra from known databases, the concentrations of carbon dioxide, water vapor, soot volume fraction, soot and gas phase temperatures can be determined within the combustion zone. Recently, this equipment has been successfully dropped in the 2.2-second drop tower and the integrity of the rig has been demonstrated.
NONLINEAR COMPRESSIONAL PULSES IN A 2D CRYSTALLIZED DUSTY PLASMA:
Fluid Physics PI Prof. J. Goree (University of Iowa) and this team report experiments with pulsed compressional waves in a 2D plasma crystal. Two-dimensional ordered lattices are found in a variety of physical systems, including dusty plasmas and colloidal suspensions, where particles interact through a screened Coulomb repulsion or Yukawa potential. Such a lattice can have either a crystalline or a liquid-like order. It sustains compressional waves and, in a crystalline or highly ordered liquid phase, transverse shear waves. Compressional pulses were launched in a two-dimensional Yukawa lattice, a hexagonal monolayer of polymer microspheres suspended in a plasma. The pulsed wave was excited by a laser beam, and nonlinear effects were observed for Mach numbers M >0.07 and for variation of particle number density > 0.1, but no steepening of the pulse was detected. The pulse propagation speed was found to be comparable to the sound speed of compressional waves launched with sinusoidal excitation. [V. Nosenko, S. Nunomura, and J. Goree, "Nonlinear Compressional Pulses in a 2D Crystallized Dusty Plasma," Physi Cal Rev Iew Letters, Volume 88, Number 21 , 27may 2002]
INVISCID DYNAMICS OF A WET FOAM DROP WITH MONODISPERSE BUBBLE SIZE DISTRIBUTION: Fluid Physics PI Prof. Holt (Boston University) and his team developed a model for nonlinear oscillations of a spherical drop composed of monodisperse aqueous foam with void fraction below 0.1. This was motivated by recent experiments involving the acoustic levitation of foam drops. The model conceptually divides a foam drop into many cells, each cell consisting of a spherical volume of liquid with a bubble at its center. By treating the liquid as incompressible and inviscid, a nonlinear equation is obtained for bubble motion due to a pressure applied at the outer radius of the liquid sphere. Upon linearizing this equation and connecting the cells at their outer radii, a wave equation is obtained with a dispersion relation for the sound waves in a bubbly liquid. For the spherical drop, this equation is solved by a normal mode expansion that yields the natural frequencies as functions of standard foam parameters. Numerical examples illustrate how the analysis may be used to extract foam parameters, such as void fraction and bubble radius, from the experimentally measured natural frequencies of a foam drop. Foams and froths are ubiquitous in nature and industry. They are the signature of vigorous, gas-entraining mixing processes in liquids. A minimalist conception of a foam would consist of a gas confined as bubbles within a liquid host. [J. Gregory McDaniel, Iskander Akhatov and R. Glynn Holt , "Inviscid dynamics of a wet foam drop with monodisperse bubble size distribution ," Physics of Fluids Volume 14, Number 6 June 2002]
PROPERTIES OF UNDERCOOLED GLASS-FORMING METALLIC ALLOYS (PUGMA): A copy of the paper, "A Novel Method for Measuring Atomic Diffusion in Reactive and High Temperature Metallic Liquids," that was submitted to the Review of Scientific Instruments has been received from the California Institute of Technology (Caltech). Dr. Jan Schroer, Dr. Sven Bossuyt, Dr. Won-Kyu Rhim, Jianzhong Li, Zhenhua Zhou, and Dr. William L. Johnson (the PUGMA Principal Investigator) are the authors. This paper defines the window of feasibility for the PUGMA diffusion experiment parameters. The PUGMA Science Concept Review Panel requested this work. Also included in the paper is an analysis of the reduction in sample temperature gradients achieved by multiple directional heating sources in a tetrahedral geometry in the Caltech Electrostatic Levitator (ESL).
JOURNAL OF MATERIAL SCIENCE LETTERS: An article, "Triggered Nucleation in Ni60Nb40 Using an Electrostatic Levitator," has been published in the Journal of Material Science Letters, vol. 21(4), pp. 301-303. The authors are T. Rathz, University of Alabama in Huntsville (UAH/SD46), M. Robinson, B. Hyers, and J. Rogers of SD46, and D. Li, Westcast Industries. The article presents the first reported externally triggered nucleation of an electrostatically levitated and undercooled (eutectic) material. This process will allow other Electrostatic Levitator investigators the capability to stimulate nucleation at a given undercooling and sample location for studying solidification velocities with high-speed video.
Additional meetings and symposia can be found at: http://microgravity.grc.nasa.gov/ugml/ugmltext.htm
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