A5049838398- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Geological and Geochemical Analysis
- High-pressure geophysics and materials
- Space Exploration and Technology
- Spacecraft and Cryogenic Technologies
- Geology and Paleoclimatology Research
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Space exploration and regulation
- Hydrocarbon exploration and reservoir analysis
- Geochemistry and Geologic Mapping
- Stellar, planetary, and galactic studies
- Space Science and Extraterrestrial Life
- Magnetic confinement fusion research
- Archaeology and ancient environmental studies
- Gamma-ray bursts and supernovae
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Elemental Analysis
- Mineralogy and Gemology Studies
- Geomagnetism and Paleomagnetism Studies
- Fusion materials and technologies
- earthquake and tectonic studies
- Fluid Dynamics Simulations and Interactions
Smithsonian Institution
2014-2025
National Museum of Natural History
2015-2025
Lunar and Planetary Institute
1996-2021
University of Hawaii System
2021
Culham Science Centre
2013
Culham Centre for Fusion Energy
2013
Forschungszentrum Jülich
2013
Case Western Reserve University
2002-2009
MetroHealth Medical Center
2009
Johns Hopkins University Applied Physics Laboratory
2007
Abstract Evaporation or freezing of water-rich fluids with dilute concentrations dissolved salts can produce brines, as observed in closed basins on Earth 1 and detected by remote sensing icy bodies the outer Solar System 2,3 . The mineralogical evolution these brines is well understood regard to terrestrial environments 4 , but poorly constrained for extraterrestrial systems owing a lack direct sampling. Here we report occurrence salt minerals samples asteroid (101955) Bennu returned...
The impact of carbon and beryllium/tungsten as plasma-facing components on plasma radiation, divertor power particle fluxes, neutral conditions in the divertors has been assessed JET both experimentally by edge fluid code simulations for plasmas low-confinement mode. In high-recycling studies show a 30% reduction total radiation scrape-off (SOL) layer when replacing (JET-C) with beryllium main chamber tungsten (JET-ILW). Correspondingly, at low-field side (LFS) plate two-fold increase...
Abstract Just as geological samples from Earth record the natural history of our planet, astromaterials hold solar system and beyond. Astromaterials acquisition curation practices have direct consequences on contamination levels hence types questions that can be answered about degree precision expected those answers. Advanced was developed a cross-disciplinary field to improve in existing collections for future sample return activities, including meteorite cosmic dust are collected Earth....
Abstract— We have investigated the porosity of a large number chondritic interplanetary dust particles (IDPs) and meteorites by three techniques: standard liquid/gas flow techniques, new, noninvasive ultrasonic technique, image processing backscattered images. The latter technique is obviously best‐suited to sub‐kilogram sized samples. also measured gas liquid permeabilities some chondrites two nondestructive pressure release technique. find that IDPs somewhat bimodal distribution. Peaks are...
Abstract— Our analyses of high quality spectra several S‐type asteroids (17 Thetis, 847 Agnia, 808 Merxia, and members the Agnia Merxia families) reveal that they include both low‐ high‐calcium pyroxene with minor amounts olivine (<20%). In addition, we find these have ratios to total >∼0.4. High‐calcium is a spectrally detectable petrologically important indicator igneous history may prove critical in future studies aimed at understanding asteroidal bodies. The silicate mineralogy...
Abstract— Melting models indicate that the composition and abundance of olivine systematically co‐vary are therefore excellent petrologic indicators. However, heliocentric distance, thus surface temperature, has a significant effect on spectra olivine‐rich asteroids. We show temperature complexly interact spectrally, must be simultaneously taken into account in order to infer accurately. find most (7/9) olivine‐dominated asteroids magnesian likely sampled mantles differentiated from ordinary...
Abstract Cosmic ray exposure (CRE) ages provide information about the parent bodies and source regions of meteorite classes. Cosmogenic noble gases are often used to quantify time scales ranging from tens ka hundreds Ma. The production rate cosmogenic is primarily controlled by a meteorite's chemical composition. Historically, an average composition for entire class or subgroup was calculate rates. At scale needed gas measurements, however, some meteorites exhibit mineral abundance...
Abstract As part of the Apollo Next‐Generation Sample Analysis (ANGSA) program, we provide bulk composition, mineralogy, petrology, and noble gas assays lunar particles soils from top half 73001/2 double‐drive tube (i.e., 73002) studied by ANGSA consortium. The are derived lithologies South Massif, including anorthosites, anorthositic breccias, high‐Ti basalts, noritic impact‐melt agglutinates, regolith breccias. breccias distinguished their inclusion high‐Mg spinel that may extend...
Abstract The OSIRIS‐REx mission returned a sample of regolith from the carbonaceous asteroid Bennu in September 2023. We present preliminary situ investigations petrology and petrography selected particles ranging size 0.5 to 3 mm. Using combination optical electron beam techniques, we investigate whole specimens polished sections belonging morphologically visually distinct categories particles. find that morphological differences are reflective petrographic petrologic differences, leading...
Abstract Troilite is a common phase in iron meteorites, but there are limited data available for the partitioning behavior of elements between troilite and solid metal. In this study, we present results experiments with coexisting Fe‐Ni metal, an S‐rich metallic liquid, troilite, conducted at 800–925°C evacuated silica tubes 1 atm. We report metal–troilite partition coefficients 22 commonly studied meteorites. find that chalcophile have affinity majority siderophile incompatible troilite. A...
Significance Martian meteorite ALH 84001 serves as a witness plate to the history of climate ∼4 Ga ago. This study describes ion microprobe δ 18 O analyses coupled with 13 C, O, and Δ 17 from stepped acid dissolution that identifies new carbonate phase distinct isotope compositions. These measurements oxygen composition carbonates within this reveal several episodes aqueous activity were strongly influenced by atmospheric chemistry. When paired carbon measurements, these data suggest ancient...
Abstract Identifying and mapping olivine on asteroid 4 Vesta are important components to understanding differentiation that body, which is one of the objectives Dawn mission. Harzburgitic diogenites main olivine‐bearing lithology in howardite‐eucrite‐diogenite ( HED ) meteorites, a group samples thought originate from Vesta. Here, we examine all Antarctic harzburgites estimate that, scales resolvable by Dawn, abundances putative harzburgite exposures surface likely at best 10–30% range, but...
Background. Surface electrical stimulation (ES) has been shown to improve the motor impairment of stroke survivors. However, surface ES can be painful and activation inconsistent from session session. Percutaneous intramuscular may an effective alternative. Objective. Evaluate effectiveness percutaneous in facilitating recovery hemiparetic upper limb chronic Methods. A total 26 survivors were randomly assigned for hand opening (n = 13) or sensory only 13). The group received cyclic,...
Abstract Northwest Africa (NWA) 8418 is an unusual chondrite whose properties do not exactly match those of any other known chondrite. It has similarities to the CV (Vigarano group), CK (Karoonda and CL (Loongana group) chondrites, but its abundance large calcium‐aluminum‐rich inclusions (CAIs) low NiO content (<0.2 wt%) matrix olivine ally it most closely with group. The absence grossular, monticellite, wollastonite, sodalite from alteration products CAIs; magnesium‐rich nature olivines...
Abstract— The carbonate mineralogy of several complex carbonate‐rich regions in Allan Hills (ALH) 84001 has been examined. These contain familiar forms carbonate, as well textural previously unreported including rosettes, planiform “slab” carbonates, distinct “post‐slab” magnesites, and carbonates interstitial to feldspathic glass orthopyroxene. Slab reveal portions the growth sequence not seen rosettes suggest that initial nucleating compositions were calcite‐rich. kinetically controlled...
Abstract Ancient, SiO 2 ‐rich achondrites have previously been proposed to formed by disequilibrium partial melting of chondrites. Here, we test the alternative hypothesis that these fractional crystallization impact melts Rumuruti (R) We identified two new melt clasts in R chondrites, one Pecora Escarpment ( PCA ) 91241 and LaPaz Icefield LAP 031275. analyzed major, minor, trace element concentrations, as well oxygen isotopes, a third had recognized (Bischoff et al. 2011) an Dar al Gani...
Abstract– We investigate the relationship between petrology and visible–near infrared spectra of unbrecciated eucrites synthetic pyroxene–plagioclase mixtures to determine how obtained by Dawn mission could distinguish several models that have been suggested for petrogenesis Vesta’s crust (e.g., partial melting magma ocean). Here, we study petrologically characterized establish spectral observables, which can be used yield mineral abundances compositions consistent with petrologic...
Abstract Nakhlites, clinopyroxenite meteorites from Mars, share common crystallization and ejection ages, suggesting that they might have been ejected the same place on Mars by event (impact) are different samples of thick volcanic flow unit or shallow sill. Mean modal abundances abundance ranges pyroxene, olivine, mesostasis vary widely among thin‐sections an individual nakhlite. Lithologic heterogeneity is main factor contributing to observed modal‐abundance variations measured in prepared...
Laboratory studies of meteorites and robotic exploration Mars reveal scant atmosphere, no evidence plate tectonics, past for abundant water, a protracted igneous evolution. Despite indirect hints, direct martian origin came with the discovery trapped atmospheric gases in one meteorite. Since then, study findings from missions have been linked. Although meteorite source locations are unknown, impact ejection modeling spectral mapping suggest derivation small craters terrains Amazonian to...