Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

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Univ., USA; Bellamy, Henry, Stanford Synchrotron Radiation Lab., USA; Borgstahl, Gloria E., Toledo Univ., USA; Pokros, Matt, Toledo Univ., USA; Cassanto, John M., Instrumentation Technology Associates, Inc., USA; [2000]; 1p; In English; ACA Annual Meeting, 23 Jul. 2000, Saint Paul, MN, USA; No Copyright; Avail: Issuing Activity; Abstract Only While macromolecule impurities may affect crystal size and morphology the over-riding question is; ”How do macromolecule impurities effect crystal X-ray quality and diffraction resolution?” In the case of chicken egg white lysozyme, crystals can be grown in the presence of a number of impurities without affecting diffraction resolution. One impurity however, the lysozyme dimer, does negatively impact the X-ray crystal properties. Crystal quality improvement as a result of better partitioning of this impurity during crystallization in microgravity has been reported’. In our recent experimental work dimer partitioning was found to be not significantly different between the two environments. Mosaicity analysis of pure crystals showed a reduced mosaicity and increased signal to noise for the microgravity grown crystals. Dimer incorporation however, did greatly reduce the resolution limit in both ground and microgravity grown crystals. These results indicate that impurity effects in microgravity are complex and may rely on the conditions or techniques employed. Author Macromolecules; Impurities; Microgravity; Crystallization; Impact Strength 20000067642 Universities Space Research Association, Huntsville, AL USA Direct Visualization of an Impurity Depletion Zone Chernov, Alex A., Universities Space Research Association, USA; Garcia-Ruiz, Juan Ma, Granada Univ., Spain; Thomas, Bill R., Universities Space Research Association, USA; [2000]; 1p; In English, 26 Aug. 2000, Nancy, France; Original contains color illustration Contract(s)/Grant(s): NCC8-66; No Copyright; Avail: Issuing Activity; Abstract Only When a crystal incorporates more impurity per unit of its volume than the impurity concentration in solution, the solution in vicinity of the growing crystal is depleted with respect to the impurity I,2. With a stagnant solution, e. g. in microgravity or gels, an impurity depletion zone expands as the crystal grows and results in greater purity in most of the outer portion of the crystal than in the core. Crystallization in gel provides an opportunity to mimic microgravity conditions and visualize the impurity depletion zone. Colorless, transparent apoferritin (M congruent to 450 KDa) crystals were grown in the presence of red holoferritin dimer as a microheterogeneous impurity (M congruent to 900 KDa) within agarose gel by counterdiffusion with Cd(2+) precipitant. Preferential trapping of dimers, (distribution coefficient K = 4 (exp 1,2)) results in weaker red color around the crystals grown in the left tube in the figure as compared to the control middle tube without crystals. The left and the middle tubes contain colored ferritin dimers, the right tube contains colored trimers. The meniscus in the left tube separate gel (below) and liquid solution containing Cd(2+) (above). Similar solutions, though without precipitants, were present on top of the middle and right tube allowing diffusion of dimers and trimers. The area of weaker color intensity around crystals directly demonstrates overlapped impurity depletion zones. Author Depletion; Impurities; Crystallization; Microgravity 20000067647 NASA Marshall Space Flight Center, Huntsville, AL USA Substrate Preparations in Epitaxial ZnO Film Growth Zhu, Shen, Universities Space Research Association, USA; Su, C.-H., NASA Marshall Space Flight Center, USA; Lehoczky, S. L., NASA Marshall Space Flight Center, USA; Harris, M. T., Air Force Research Lab., USA; Callahan, M. J., Air Force Research Lab., USA; George, M. A., Alabama Univ., USA; [2000]; 1p; In English; 12th; Crystal Growth and Epitaxy, 13-18 Aug. 2000, Vail, CO, USA Contract(s)/Grant(s): NCC8-66; No Copyright; Avail: Issuing Activity; Abstract Only Epitaxial ZnO films were grown on the two polar surfaces (O-face and Zn-face) of (0001) ZnO single crystal substrates using off-axis magnetron sputtering deposition. Annealing-temperature dependence of ZnO substrates was studied. ZnO films grown on sapphire substrates have also been investigated for comparison purposes and the annealing temperature of A1203 substrates is 1000 C. Substrates and films were characterized using photoluminescence (PL) spectrum, x-ray diffraction, atomic force microscope, energy dispersive spectrum, and electric transport measurements. It has been found that the ZnO film properties were different when films were grown on the two polarity surfaces of ZnO substrates and the A1203 substrates. An interesting result shows that high temperature annealing of ZnO single crystals will improve the surface structure on the O-face surface rather than the opposite surface. The measurements of homoepitaxial ZnO films indicate that the O-terminated surface is better for ZnO epitaxial film growth. Author Epitaxy; Substrates; Zinc Oxides; Metal Films; Single Crystals 206
20000067648 NASA Marshall Space Flight Center, Huntsville, AL USA Mechanisms for the Crystallization of ZBLAN Ethridge, Edwin C., NASA Marshall Space Flight Center, USA; Tucker, Dennis S., NASA Marshall Space Flight Center, USA; [2000]; 1p; In English; Microgravity Materials, 8 Jun. 2000, Huntsville, AL, USA; Sponsored by NASA, USA; No Copyright; Avail: Issuing Activity; Abstract Only A number of research teams have observed that glass forming melts that are solidified in low-g exhibit enhanced glass formation. This project will examine one of these glasses, the heavy metal fluoride glass ZBLAN. A four year ground based research program has been approved to examine the crystallization of ZBLAN glasses with the purpose of testing a theory for the crystallization of ZBLAN glass. The theory could explain the general observations of enhanced glass formation of other glasses melted and solidified in low-g. Fluid flow in 1-g results from buoyancy forces and surface tension driven convection. This fluid flow can introduce shear in undercooled liquids in 1-g. In low-g it is known that fluid flows are greatly reduced so that the shear rate in fluids in low-g are extremely low. It is believed that fluids may have some weak structure in the absence of flow. Even very small shear rates could cause this structure to collapse in response to the shear. A general result would be shear thinning of the fluid. The hypothesis of this research is that: Shear thinning in undercooled liquids increases the rate of nucleation and crystallization of glass forming melts. Shear of the melt can be reduced in low-g enhancing undercooling and glass formation. Samples will be melted and quenched in 1-g under quiescent conditions at a number of controlled cooling rates to determine times and temperatures of crystallization and heated at controlled heating rates to determine kinetic crystallization parameters. Experiments will also be performed on the materials while under controlled vibration conditions and compared with the quiescent experiments in order to evaluate the effect of shear in the liquid on crystallization kinetics. After the experimental parameters are well known, experiments will be repeated under low-g (and 2-g) conditions on the KC-135 aircraft during low-g parabolic maneuvers. The results will determine the effects of shear on crystallization. Our experimental setups will be designed with low-g experiments in mind and will be tested as breadboard low-g experiments. It is very likely that the thermal analysis instrumentation can be adapted to be run in the microgravity glovebox facilities. Critical space experiments may result to test the theory at longer low-g time experiments in space. Author Crystallization; Glass; Metal Fluorides; Melts (Crystal Growth) 77 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS �� 20000062449 Forschungszentrum Rossendorf e.V., Dresden, Germany Kaons in nuclear matter Kolomeitsev, E. E.; Feb. 28, 1997; 170p; In German; In English Report No.(s): DE99-715823; FZR-167; No Copyright; Avail: Department of Energy Information Bridge The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon- nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. NTIS Kaons; Matter (Physics); Nucleons 20000062715 Joint Inst. for Nuclear Research, Bogolyubov Lab. of Theoretical Physics, Dubna, USSR Is the Casimir effect relevant to sonoluminescence Nesterenko, V. V.; Pirozhenko, I.; Dec. 31, 1998; 12p; In English Report No.(s): DE99-607974; JINR-E-2-98-40; No Copyright; Avail: Department of Energy Information Bridge The Casimir energy of a solid ball (or cavity in an infinite medium) is calculated by a direct frequency summation using the contour integration. The dispersion is taken into account, and the divergences are removed by making use of the zeta function technique. The Casimir energy of a dielectric ball (or cavity) turns out to be positive, it being increased when the radius of the ball decreases. The latter eliminates completely the possibility of explaining, via the Casimir effect, the sonoluminescence for 207
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Scientific and Technical Aerospace
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Introduction Scientific and Technic
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Subject Divisions Table of Contents
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ground equipment and systems. For a
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Subject Categories of the Division
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48 Oceanography 139 Includes the ph
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72 Atomic and Molecular Physics 191
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Document Availability Information T
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Avail: NASA Public Document Rooms.
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NASA CASI Price Tables — Effectiv
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ALABAMA AUBURN UNIV. AT MONTGOMERY
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20000061433 Pisa Univ., Dipartiment
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English; 34th; 34th Thermophysics C
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ciency of the generated derivative
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20000063509 NASA Glenn Research Cen
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05 AIRCRAFT DESIGN, TESTING AND PER
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A long tradition of aerodynamic des
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sonic and transonic cases will be p
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20000061449 British Aerospace Publi
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20000064593 NASA Langley Research C
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performance required for a proposed
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ment cost and create better product
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tion (NPSS), is focused on the inte
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surface measurement techniques used
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with emphasis on the search for lin
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20000063520 NASA Kennedy Space Cent
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primary issues for it’s adaptatio
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Footage shows the night vertical ta
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20000067665 NASA Kennedy Space Cent
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necessary for ignition modeling, or
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engine lifetime, and high power ope
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24 COMPOSITE MATERIALS ��
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ments. For the screening of liner m
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formation of a neutral, fluorescent
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20000065655 Ames Lab., IA USA Funda
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This is a second Triennial Conferen
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of completely charged PSSNa solutio
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20000064100 NASA Langley Research C
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Spacecraft in low Earth orbit (LEO)
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Pressure gradients, i.e. pressure h
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agreed that the NO(sub x) levels co
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tectural approach to extending the
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20000064078 Physics and Electronics
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20000064925 Institute for Human Fac
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20000062455 National Inst. of Stand
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Added Analysis (Risk Reduction); 6)
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shipboard electrical power generati
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20000067664 Jet Propulsion Lab., Ca
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other, The theoretical framework go
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figures compare the lift and pitchi
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ment phase demonstrate desired feat
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esolution mode with resolving power
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to track 1% or 0.5% changes was hig
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20000067643 NASA Marshall Space Fli
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37 MECHANICAL ENGINEERING ��
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solver based on overset grid techno
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20000067659 NASA Marshall Space Fli
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20000064621 Rensselaer Polytechnic
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that for a specific example of a be
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km x 1000 km). As with the nearly c
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20000064527 Analytical Imaging and
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20000064533 Austin State Univ., Dep
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20000064539 California Univ., Inst.
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in Yellowstone National Park. We ar
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terns of community hysteresis based
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tion model (DEM) fitting to the sca
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The Carolina slate belt is a 10- to
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20000063373 Los Alamos National Lab
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20000064912 New Energy and Industri
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and discusses the issues and resear
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The objective of this study was to
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distributions with engine test resu
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7.6, while the 1926 events appear t
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We investigate the compositional di
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Flight Center, USA; Moore, T. E., N
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This report presents the Applied Me
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in Goa, India, by 3 - 4 days. Wind
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51 LIFE SCIENCES (GENERAL) Includes
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20000062717 Joint Inst. for Nuclear
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during 50% (SD 4%) of the breathing
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20000064711 Massachusetts Inst. of
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The analysis of this smaller data s
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vided a functional helmet mount. Th
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Page 179 and 180: The goal of multi-image classificat
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Page 189 and 190: declarations with a pattern recogni
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Page 239 and 240: ecoming almost too cumbersome to be
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Page 257 and 258: A ABERRATION, 143, 198 ABRASION, 22
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Page 267 and 268: SPACE PLATFORMS, 38 SPACE PROBES, 2
Page 269 and 270: WIND PROFILES, 137 WIND TUNNEL TEST
Page 271 and 272: Brown, Andy, 38 Brown, April S., 20
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Warner, J. D., 63 Warren, James, 16
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Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

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