Code UG Weekly Notes 4-11-02


Physical Sciences Division
Weekly Highlights for Week Ending 4/11/2002

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

GENERAL

PATENT ISSUED TO MEMBER OF MICROGRAVITY SCIENCE AND APPLICATIONS DEPARTMENT (MSAD) : A U.S. patent was issued for "Oxide Films and Process for Preparing Same" on 01/29/02. The inventors are H. W. White (University of Missouri), Shen Zhu, Universities Space Research Association (USRA/MSFC), and Y. Ryu (University. of Missouri).

MEMBER OF MICROGRAVITY SCIENCE AND APPLICATIONS DEPARTMENT (MSAD) TO RECEIVE NASA SOFTWARE AWARD: Dr. James H. Adams, Jr. (MSFC), has been selected to receive a Software Award from the NASA Inventions and Contributions Board for his development of the Cosmic Ray Effect on Microelectronics (CREME96) engineering assessment tool. CREME96 is widely used by engineers to estimate the effects of cosmic ray on spacecraft electronics. For more information, go to http://crsp3.nrl.navy.mil/creme96/

MICROGRAVITY RESEARCH PUBLICATION/CITATION DATABASE:: The current plan is to deliver the Microgravity Research Publication/Citation database to the Physical Science Division (PSD) of the Office of Biological and Physical Research (OBPR) at NASA Headquarters in September 2002. In addition, directions on how to produce various metrical reports, along with recommendations for use of the database in conjunction with the Task Book, will be provided. This database is based on the bibliographies contained in the OBPR PSD Task Book; the Science Citation Index is being used to identify citations of published articles. Tasks in progress include: (1) eliminating duplicate publication entries, (2) obtaining missing publication data, (3) correcting publication dates and names of journals, (4) distinguishing among articles published in peer reviewed journals vs. selected presentations vs. other written material/documents (as listed in the Task Book), (5) completing citation entries, and (6) making corrections and updates to associated investigation/investigator data.

TRANSFER OF DYNAMX TECHNOLOGY TO SMALL BUSINESS: The DYNAMX (Critical Dynamics in Microgravity Experiment) group at the University of New Mexico has transferred their miniature cryogenic valve technology to a small business named EMD located in Albuquerque. There have been a sufficient number of requests for this new valve for EMD to offer it commercially. This miniature valve is a two-gram valve that has been flight qualified by the DYNAMX team.

EDUCATION and OUTREACH

ENHANCED GASEOUS NITROGEN (EGN) DEWAR MONTANA TEACHER WORKSHOP: As a part of expanding EGN education participation into the Northwest Rockies, the Principle Investigator conducted a teacher training workshop in Missoula, Montana, on 02/20/02. Teachers from the local school area and representatives from the surrounding states, including Utah, Idaho, and Colorado, attended the workshop. The workshop consists of an introduction and overview of the EGN flight program, a brief explanation of why experiments are conducted in Microgravity, an overview of structural biology and the role of crystallography, and hands-on training of the participants using the classroom kit. Montana Senator, Conrad Burns, visited the workshop and made a few remarks regarding the role of NASA in technology transfer while assisting by volunteering to load a flight sample. Near the conclusion of the workshop, Dr. Kathie Olsen and Dr. Lloyd Chestnut, University of Montana, signed a Memorandum of Agreement outlining other activities between the University of Montana and NASA.

EDUCATIONAL WORKSHOPS FOR STUDENT ACCESS TO SPACE PROGRAM: Between 01/23/02 and 02/22/02, more than 100 high school students and their teachers participated in workshops to learn methods of crystallization of biological macromolecules and the use of Enhanced Gaseous Nitrogen (EGN) Dewar. The workshops were held at the University of Texas at Austin, the University of Alabama in Huntsville, the University of South Alabama in Mobile, and in high schools in Titusville, FL, and Missoula, MT. The samples prepared during these workshops were stored in MSFC's Structural Biology Laboratory and have been loaded in the EGN Dewar for the STS-110 mission in April 2002. This will be the fourth launch of the EGN Dewar to the International Space Station, and it is noteworthy that student samples have been included in each flight.

INTERNATIONAL SPACE STATION RESEARCH PRESENTATION FOR THE "TECHNOLOGY IN MOTION" TEACHER TRAINER WORKSHOP: Dr. Bill Carswell, University of Alabama in Huntsville (UAH/MSFC), at the request of the MSFC Educational Programs Office Educator Resource Center, gave a presentation, entitled "Accessing Space Station Research On-Line," at the "Technology in Motion" workshop on Friday, 3/15/2002. Workshop attendees were individuals employed by the State of Alabama Department of Education to train teachers in the use of technology to improve the educational process for grade school students. The presentation outlined the research being performed on the International Space Station and highlighted some of the useful Internet resources that can be used by both teachers and students to learn more about specific subjects in space station research and to stay on top of current events.

SHUTTLE FLIGHT PROGRAM

ISS FLIGHT PROGRAM

*** SUCCESSFUL PHYSICS OF COLLOIDS IN SPACE (PCS) EXPERIMENT CONCLUDED ON ISS: PCS experiment to date has provided excellent scientific data that show some totally unexpected behavior of colloids in microgravity environment. The Principal Investigator team considers the experiment highly successful and is interpreting data obtained from all of the 8 colloid samples, despite an on orbit flight system computer boot-up problem. After exhausting the troubleshooting procedures during Week 14, NASA Glenn and the ISS program have agreed to terminate any further on-orbit recovery actions for the flight hardware. Efforts are underway formally requesting descent of both the Avionics Section and the Test Section on ISS Flight UF-2 (launch NET 5/31/02) to enable diagnosis and repair activities to occur on the ground at Glenn, beginning in early July. A review board will be put in place at Glenn to support these anomaly diagnosis and repair efforts. A timely return of the Test Section aids in post-flight characterization of the PCS samples and helps ensure PCS+ remaining on schedule. PCS+ is a reflight of the hardware with eight new samples from PI, Prof. Paul Chaikin of Princeton University on ISS Flight 12A.1.

MICROGRAVITY RESEARCH PROGRAM OFFICE (MRPO) PAYLOAD OPERATIONS STATUS ON THE INTERNATIONAL SPACE STATION (ISS) UF1 STAGE: Have successfully completed Week#15 (3/24-30/02) of Increment 4 UF1 Stage, and have entered into Week#16 (3/31-4/6/02). The plant growth experiment will have their final plant tissue collection on 4/3/02 before returning on Flight 8A. The colloids study experiment hardware will be returned on Flight UF2 instead of Flight 9A to continue their troubleshooting on the ground and facilitate their return for a new study on Flight 12A.1. The MRPO payloads scheduled to fly on Flight 8A are ready for flight.

MICROGRAVITY RESEARCH PROGRAM (MRP) PAYLOAD OPERATIONS STATUS ON THE INTERNATIONAL SPACE STATION (ISS) UF1 STAGE: All MRP payloads have completed their scheduled operations and are looking forward to a busy week (4/7-13) of joint operations with the STS-110/ISS 8A crew. The plant growth experiment is proceeding with plant drying to prepare for Flight 8A descent. The colloids study experiment hardware will be returned on Flight UF2. The MRP payloads launched on Flight 8A includes experiments for protein crystal growth, processing of biomedical materials and zeolite crystal growth.

FIRST MATERIALS SCIENCE RESEARCH RACK (MSRR-1): MSRR-1 completed final negotiations with European Space Agency (ESA) representatives on the content of the Interface Control Document between the ESA Materials Science Laboratory (MSL) and the MSRR-1. The document was signed by both parties on 03/21/02. This represents a significant accomplishment in implementation of the International Agreement between the two agencies, and was required prior to acceptance of the ground MSL at the Marshall Space Flight Center (MSFC) later this year for integration into the ground MSRR-1. In addition, representatives of the MSRR-1 Project, the University of Alabama in Huntsville (UAH), and the Space Products Division (SPD) signed the MSRR-1 to SPD Experiment Module (EM) Interface Control Document on 04/02/02. This represents a significant milestone in the integration of the SPD EM into the MSRR-1 integrated payload.

INTERNATIONAL SPACE STATION (ISS) PAYLOAD CUSTOMER SUPPORT INITIATIVE KICK-OFF: Work is ongoing regarding a new initiative for ISS Customer Support and Feedback. John-David Bartoe/Johnson Space Center (JSC) Code OZ, ISS Research Manager, is leading this effort. A team has been assembled from the ISS Research Program Offices (RPOs) and implementing centers to develop the approach and processes for collecting customer feedback from Payload Developers/Principle Investigators that have flown on ISS. The team plans on initiating the first post-increment feedback interview with Increment 4 payload developers in June 2002.


SCIENCE HIGHLIGHTS

FLUID PHYSICS:

NUMERICAL SIMULATION OF BUBBLE MERGER PROCESS ON A SINGLE NUCLEATION SITE DURING POOL NUCLEATE BOILING: Fluid Physics PI Prof. Dhir (UCLA) and his team has investigated a bubble merger process on a single nucleation site by numerically solving the equations governing conservation of mass, momentum and energy in the vapor and liquid phases. The vapor-liquid interface is captured by a level set method that can easily handle breaking and merging of the interface. The level set method is modified to include the effects of phase change at the interface and contact angle at the wall. Also, the evaporative heat flux from the thin liquid film that forms underneath a growing bubble attached to the wall is incorporated in the analysis. Based on the numerical simulations, the effect of bubble merger on vapor removal rate, flow field and heat transfer has been quantified. The bubble merger pattern predicted numerically has been found to compare well with the experimental observations. The results are reported in the following paper:

G. Son, N. Ramanujapu and V. K. Dhir "Numerical Simulation of Bubble Merger Process on a Single Nucleation Site During Pool Nucleate Boiling," Journal of Heat Transfer, Vol. 124, pp 51- 63, February 2002.

LINEAR INSTABILITY ANALYSIS OF A HORIZONTAL TWO-PHASE FLOW IN THE PRESENCE OF ELECTROHYDRODYNAMIC EXTRACTION FORCE: Fluid Physics PI Prof. Seyed-Yagoobi (Texas A&M) investigated the flow regimes associated with a horizontal internal two-phase (liquid-vapor) flow in the presence and absence of the electric field with the linear stability analysis. The momentum interchange due to the entrainment between the two phases is included in the analysis. The presence of the electric field promotes instability by providing the electrohydrodynamic (EHD) extraction force. Qualitative stability maps for the annular two-phase flow are provided with and without the electric field presence. Onset of the instability is compared with the experimental data and it is shown that the transition between the EHD-enhanced and EHD-suppressed convective boiling heat transfer is located near the annular-to-mist transition region. These results are reported in the following paper:

Y. Feng and J. Seyed-Yagoobi, "Linear Instability Analysis of a Horizontal Two-Phase Flow in the Presence of Electrohydrodynamic Extraction Force," Journal of Heat Transfer, Vol. 124, pp 102- 110, February 2002

FUNDAMENTAL PHYSICS:

CASIMIR EFFECT FOUND IN MANY SYSTEMS: Moses Chan and Rafael Garcia of Penn State University have published an article describing their recent measurements of the Casimir effect observed in thin films of 3He-4He mixtures. According to the authors, that the same mathematical formulation can be used to describe phenomena in widely different systems is one of the most beautiful aspects of physics. H. B. G. Casimir first reported these effects in 1948 in measurements of the confinement of zero-point electromagnetic fluctuations between two plates in a vacuum. The critical Casimir effect has been observed more recently in thin films of pure helium absorbed on copper surfaces, and in binary liquid films. The tricritcal point of 3He-4He mixtures provides yet another region where the critical fluctuations are limited by the size of the measuring apparatus, so one expects a Casimir force to appear.

In the phase diagram of 3He-4He mixtures, the tricritical point is the point where the line of superfluid transitions terminates at the top of the coexistence region. As this point is approached, the system is expected to exhibit an attractive Casimir force for symmetric order parameter boundary conditions, but the force will be repulsive if nonsymmetric boundary conditions prevail. The measurements reported in this paper find that the Casimir force in this system is a repulsive force.

The details can be found in the authors' paper "Critical Casimir Effect near the 3He-4He Tricritical Point," Physical Review Letters 88, 086101 (2002).

VORTEX NUCLEATION IN A STIRRED BOSE-EINSTEIN CONDENSATE: Dissipation and turbulence in superfluid flow often involves the creation and subsequent motion of quantized vortices. Since vortices are topological defects, they may only be created in pairs, or can enter a system individually from its boundary. The nucleation process has been a subject of much theoretical interest. Experiments with Bose-Einstein condensates in atom traps are well suited to test theories of nucleation because the boundary of the condensate is well controlled, and vortices can be directly imaged.

In previous work, the MIT group of Wolfgang Ketterle had observed vortex lattices in stirred Bose-Einstein condensates. By varying the stirring parameters, they have now explored different mechanisms for vortex nucleation. A large stirrer, with a beam waist comparable to the condensate radius, showed enhanced vortex generation at discrete frequencies. The figure below shows the number of vortices versus the frequency of rotation of the laser beam using 2-, 3- and 4-point patterns for the stirring beams. These resonances were close to the frequencies of excitation for surface modes of different multipolarity. This observation confirms the role of discrete surface modes in vortex formation.

However, when they used a tightly focused (beam waist 5 ?m) laser beam as stirrer, they observed a broad response as a function of the frequency of the stirrer's motion, and no resonances (see figure). Furthermore, vortices could be generated well below the critical rotation frequency for the excitation of surface modes. This suggests a local mechanism of vortex generation involving hydrodynamic flow and local turbulence.

These results were published in the paper "Vortex Nucleation in a Stirred Bose Einstein Condensate," by C. Raman, J.R. Abo-Shaeer, J.M. Vogels, K. Xu, and W. Ketterle in Physica Review Letters 87, 210402 (2001)

UPCOMING EVENTS

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

The MRPO Program Calendar can be found at:
http://webcal.msfc.nasa.gov/webevent.cgi?cmd=opencal&cal=cal85&

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