A5086088339- Astro and Planetary Science
- Planetary Science and Exploration
- Geochemistry and Elemental Analysis
- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Geomagnetism and Paleomagnetism Studies
- Stellar, planetary, and galactic studies
- Recycling and utilization of industrial and municipal waste in materials production
- Bauxite Residue and Utilization
- Concrete and Cement Materials Research
- Radioactive contamination and transfer
- Analytical chemistry methods development
- Astronomical and nuclear sciences
- Hydrocarbon exploration and reservoir analysis
- Extraction and Separation Processes
- Geological and Geochemical Analysis
- Recycled Aggregate Concrete Performance
- Recycling and Waste Management Techniques
- Methane Hydrates and Related Phenomena
- Thallium and Germanium Studies
- Silicon Effects in Agriculture
- Nuclear physics research studies
- High-pressure geophysics and materials
Hong Kong Polytechnic University
2024
Rutgers, The State University of New Jersey
1994-2008
University of Rhode Island
1997-1999
Abstract— We have measured the 13 C/ 12 C and 14 ratios in CO 2 released by acid etching of carbonate‐bearing SNC meteorites Allan Hills 84001 Nakhla. Most is strongly enriched C. In 10 out samples, 15‰ <δ < 55‰. Terrestrial values carbonateδ from weathering products are generally between −10 +10‰. Two leachate samples especially rich C, ALH 84001,27 Nakhla 25, elemental Si/Mg much lower than those bulk activities that expected for terrestrial carbonates. The former observation...
Two main types of material survive from the Canyon Diablo impactor, which produced Meteor Crater in Arizona: iron meteorites, did not melt during impact; and spheroids, did. Ultrasensitive measurements using accelerator mass spectrometry show that meteorites contain about seven times as much nickel-59 spheroids. Lower average contents spheroids indicate they typically came 0.5 to 1 meter deeper impactor than meteorites. Numerical modeling for an impact velocity 20 kilometers per second shows...
Abstract— We report measurements of 26 Al and 10 Be activities in nine ordinary chondrites the light noble gas concentrations 36 Cl 41 Ca subsets those meteorites. All but Murray have low 21 Ne (<1.0 × −8 cm 3 STP/g) previously been used to estimate production rates. Ladder Creek, Murchison, Sena, Timochin inventories cosmogenic radionuclides that are compatible with a single stage irradiation give rates consistent standard L‐chondrite value 0.33 STP/g/Ma. In contrast, Cullison, Guenie,...
Abstract— We report measurements of 26 AI, 10 Be, 41 Ca, and 36 Cl in the silicate metal phases 11 mesosiderites, including several specimens each Budulan Estherville, brecciated meteorite Bencubbin, iron Udei Station. Average production rate ratios (atom/atom) for phase samples from Estherville are Al/ Be = 0.77 ± 0.02; Cl/ 5.3 0.2. For a larger set meteorites that includes other we find 0.72 0.01 4.5 The average Ca/ ratio is 1.10 0.04 separates four small falls. Ca activities dpm/(kg Ca)...
Abstract— The Peekskill H6 meteorite fell on 1992 October 9. We report extensive measurements of cosmic‐ray produced stable nuclides He, Ne, and Ar, the radionuclides 22 Na, 60 Co, 14 C, 36 Cl, 26 Al, 10 Be, track densities. After correction for shielding via Ne/ 21 Ne ratio, concentrations 3 38 Ar give an average exposure age 25 Ma, which is considered to be a lower limit true value. Be/ 32 Ma falls onto peak in H‐chondrite distribution. activities Be are all close maximum values expected...
Concentrations of magnesium isotopes in the iron meteorites Charlotte, Picacho, Tlacotepec, and Grant between 0.15 5 ppbw have been measured by glow discharge mass spectrometry, typically with a precision 15%. The 25Mg/24Mg 26Mg/24Mg ratios are well above terrestrial values most samples indicating presence component produced cosmic rays. Inferred concentrations cosmogenic 26Mg range from barely detectable to 0.255 ppb mass. 26Al 10Be activities were same four other accelerator spectrometry....
Abstract— The isotopic abundances of Ni in 17 metallic spheroids from Meteor Crater, Arizona, were determined by inductively coupled plasma mass spectrometry (ICP‐MS). Sixteen have normal abundances. A 17th shows a marginally detectable fractionation 0.40 ± 0.14 %/AMU favor the heavier isotopes. general absence indicates that open system evaporation caused little loss Ni. Variable activities cosmogenic radionuclides 10 Be and 26 Al measured accelerator separate suites spheroids. Activities...