A5059360994- Astro and Planetary Science
- Planetary Science and Exploration
- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- High-Velocity Impact and Material Behavior
- Fusion materials and technologies
- Space Exploration and Technology
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Ionosphere and magnetosphere dynamics
- High-pressure geophysics and materials
- Particle Accelerators and Free-Electron Lasers
- Isotope Analysis in Ecology
- Spacecraft and Cryogenic Technologies
- Space Satellite Systems and Control
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Electromagnetic Launch and Propulsion Technology
- Geology and Paleoclimatology Research
- Hydrocarbon exploration and reservoir analysis
- Ion-surface interactions and analysis
- Advanced Fiber Optic Sensors
- Diamond and Carbon-based Materials Research
United States Army
2006-2024
Anglia Ruskin University
2013-2024
United States Army Combat Capabilities Development Command
2024
United States Department of the Army
2024
U.S. Army Combat Capabilities Development Command Ground Vehicle System Center
2024
University of Kent
2013-2023
Oak Ridge National Laboratory
2004-2021
New Mexico State University
2021
Max Planck Institute for Plasma Physics
2021
Gillette Children's Specialty Healthcare
2014
Abstract The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor and plasma volume) restarted operation after the assembly of a graphite heat shield 10 inertially cooled island divertor modules. This paper reports on results from first high-performance operation. Glow discharge conditioning ECRH discharges in helium turned out to be important for density edge radiation control. Plasma densities with central electron temperatures were routinely achieved...
Abstract Research on magnetic confinement of high-temperature plasmas has the ultimate goal harnessing nuclear fusion for production electricity. Although tokamak 1 is leading toroidal magnetic-confinement concept, it not without shortcomings and community therefore also pursued alternative concepts such as stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) field geometry. The availability this additional dimension opens up an extensive configuration...
The hypervelocity impact facilities of the University Kent are described. They comprise a 2 MV Van de Graaff accelerator for electrostatic acceleration dust particles (mass and velocities ) two-stage light gas gun firing millimetre-sized at . Results ionization studies using iron accelerated in hitting variety metal targets (gold, silver, indium, iron, rhodium molybdenum) presented. Over range , yields found to be similar within factor 20 low velocity converge five high velocity. is used...
The Advanced Toroidal Facility (ATF), now under construction at Oak Ridge National Laboratory, will be the world’s largest stellarator experiment when it begins operation in early 1987. It have a 2.1-m major radius and 0.3-m average plasma radius, magnetic field capability of up to 2 T for 5-s pulse 1 steady state, 5 MW heating. ATF is designed study wide range toroidal confinement issues, including stability high-beta plasmas, low-collisionality transport, impurity behavior, configuration...
The next step in the Wendelstein stellarator line is large superconducting device 7-X, currently under construction Greifswald, Germany. Steady-state operation an intrinsic feature of stellarators, and one key element 7-X mission to demonstrate steady-state plasma conditions relevant for a fusion power plant. device, on hand, requires implementation special technologies, giving rise technical challenges during design, fabrication assembly such device. On other also physics development at...
Abstract We present recent highlights from the most operation phases of Wendelstein 7-X, advanced stellarator in world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens seconds. Pellet fueling allows plasma reduced ion-temperature-gradient turbulence, during such phases, overall is so (energy often 200 ms) that attained density temperature profiles would not possible less optimized devices, since...
Abstract– The fluence of dust particles <10 μm in diameter was recorded by impacts on aluminum foil the NASA Stardust spacecraft during a close flyby comet 81P/Wild 2 2004. Initial interpretation craters for impactor particle dimensions and mass based upon laboratory experimental simulations using projectiles less than >10 resulting linear relationship projectile to crater extrapolated smaller sizes. We now describe new calibration program firing very small monodisperse silica (470...
ABSTRACT Although there are several reports on rotavirus inoculation of nonhuman primates, no reliable model exists. Therefore, this study was designed to develop a rhesus macaque for studies. The goals were obtain wild-type and evaluate it as challenge virus Once shown be endemic within the colony at Tulane National Primate Research Center, stool specimens collected from juvenile animals (2.6 5.9 months age) without evidence previous infection examined antigen. Six 10 shed during 10-week...
Physics issues are discussed for compact stellarator configurations which achieve good confinement by the fact that magnetic field modulus |B| in co-ordinates is dominated poloidally symmetric components. Two distinct configuration types considered: (1) those their drift optimization and rotational transform at low β bootstrap current appropriate plasma shaping; (2) have a greater reliance on currents supplying obtaining quasi-poloidal symmetry. Stability analysis of latter group devices...
Abstract— Aluminum foils of the Stardust cometary dust collector are peppered with impact features a wide range sizes and shapes. By comparison to laboratory shots known particle dimensions density, using same velocity incidence geometry as Wild 2 encounter, we can derive size mass grains. Using scanning electron microscopy (SEM) foil samples (both flown on mission impacted in laboratory) have recognized feature shapes from which interpret density internal structure. We documented...
The ionic plasma produced by a hypervelocity particle impact can be analysed to determine compositional information for the original using time-of-flight mass spectrometer. Such methods have been adopted on interplanetary dust detectors perform in-situ analyses of encountered grains, example, Cassini Cosmic Dust Analyser (CDA). In order more fully understand data returned such instruments, it is necessary study their response impacts in laboratory. Accordingly, are shown here spectra...
Abstract— Metallic aluminum alloy foils exposed on the forward, comet‐facing surface of aerogel tray Stardust spacecraft are likely to have been impacted by same cometary particle population as dedicated impact sensors and collector. The ability soft record hypervelocity impacts bowl‐shaped craters offers an opportunistic substrate for recognition particles a potentially wide size range. In contrast surveys conducted samples from low Earth orbit, simple encounter geometry Wild‐2, with known...
AbstractThe use of a fusion component testing facility to study and establish, during the ITER era, remaining scientific technical knowledge needed by Demo is considered described in this paper. This aims test components an integrated nuclear environment, for first time, discover understand underpinning physical properties, develop improved further testing, time-efficient manner. It requires design with extensive modularization remote handling activated components, flexible hot-cell...
Exposing seedlings of the flax, Linum usitatissimum L., to a variety weak environmental stresses followed by 2 day calcium deprivation, triggers common response production epidermal meristems (actively dividing groups cells) in hypocotyl, which is part stem between root and cotyledons (the pre-existing leaves embryo). This reaches plateau 10-20 after month case mechanical stimulation cold shock. Recently, we have shown that radiation from global system for mobile communication (GSM)...
Abstract— The known encounter velocity (6.1 kms −1 ) and particle incidence angle (perpendicular) between the Stardust spacecraft dust emanating from nucleus of comet Wild‐2 fall within a range that allows simulation in laboratory light‐gas gun (LGG) experiments designed to validate analytical methods for interpretation impacts on aluminum foil components collector. Buckshot wide size, shape, density mineral, glass, polymer, metal grains, have been fired impact perpendicularly samples Al...
The survival of organic molecules in shock impact events has been investigated the laboratory. A frozen mixture anthracene and stearic acid, solvated dimethylsulfoxide (DMSO), was fired a two-stage light gas gun at speeds ~2 ~4 km s(-1) targets that included water ice, water, sand. This involved pressures range 2-12 GPa. It found projectile materials were present elevated quantities after some cases crater ejecta as well. For DMSO impacting 1.9 45° incidence, we quantify surviving fraction...
The presence and accessibility of a sub-ice-surface saline ocean at Enceladus, together with geothermal activity rocky core, make it compelling location to conduct further, in-depth, astrobiological investigations probe for organic molecules indicative extraterrestrial life. Cryovolcanic plumes in the south polar region Enceladus enable use remote situ sampling analysis techniques. However, efficient plume transportation captured materials an analyzer present unique challenges mission. A...
Abstract— The capture in aerogel of 106 μm diameter glass beads is investigated for impact speeds 1 to 7.5 km s −1 . Three different densities were used, 60,96 and 180 kg m −3 It was found that the length penetration track increases with speed until a maximum reached. Above decreases. This behaviour similar which has previously been observed particles impacting polystyrene foams porous alumina. Whilst not be an unambiguous indicator speed, excavated volume suitable indictor speed. Further,...
Abstract— New experimental results show that Stardust crater morphology is consistent with interpretation of many larger Wild 2 dust grains being aggregates, albeit most low porosity and therefore relatively high density. The majority large (i.e. those carrying the cometary mass) probably had density 2.4 g cm −3 (similar to soda‐lime glass used in earlier calibration experiments) or greater, 25% less, akin consolidated carbonaceous chondrite meteorites, much lower than 80% suggested for...