A5078024348- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Geology and Paleoclimatology Research
- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Radioactive Decay and Measurement Techniques
- High-pressure geophysics and materials
- Nuclear physics research studies
- Spacecraft and Cryogenic Technologies
- Geological and Geochemical Analysis
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- Geological and Geophysical Studies
- Radioactive contamination and transfer
- Particle accelerators and beam dynamics
- Microwave Dielectric Ceramics Synthesis
- Gamma-ray bursts and supernovae
- Dielectric properties of ceramics
- Hydrocarbon exploration and reservoir analysis
- Advanced Condensed Matter Physics
- Structural Integrity and Reliability Analysis
- Dark Matter and Cosmic Phenomena
- Magneto-Optical Properties and Applications
- Calibration and Measurement Techniques
Johnson Space Center
2016-2019
Oak Ridge Associated Universities
2014-2018
Oak Ridge National Laboratory
2018
Associated Universities, Inc.
2014-2016
Physical Research Laboratory
2010-2016
Centre de Recherches Pétrographiques et Géochimiques
2012-2014
Centre National de la Recherche Scientifique
2012-2014
Université de Lorraine
2012-2014
Hindustan Institute of Technology and Science
2014
Indian Institute of Technology Kharagpur
2007-2008
Yttrium (Y) modified nanocrystalline samples of BiFeO3 (BFO) were prepared by a metal ion ligand complex-based precursor-solution evaporation method. Partial substitution Y (0–15%) at the Bi site results in structural change (rhombohedral to tetragonal) and single phase formation. With increasing concentration, enhancement dielectric ordering, reduction loss tangent improvement magnetic ordering BFO observed. Diffuse peaks both permittivity observed 207 °C 222 °C, respectively, for 15% Y. In...
The presence of about a dozen short-lived nuclides in the early solar system, including 60Fe and 26Al, has been established from isotopic studies meteorite samples. An accurate estimation system initial abundance 60Fe, distinct product stellar nucleosynthesis, is important to infer source this nuclide. Previous regard suffered lack exact knowledge time formation analyzed We present here results obtained first combined study 26Al records objects remove ambiguity. Chondrules unequilibrated...
The possibility of establishing an accurate relative chronology the early solar system events based on decay short-lived 26Al to 26Mg (half-life 0.72 Myr) depends level homogeneity (or heterogeneity) and Mg isotopes. However, this is difficult constrain precisely because very high precision needed for determination isotopic ratios, typically ±5 ppm. In study, we report first time a detailed analytical protocol developed in situ measurements (25Mg/24Mg 26Mg/24Mg as well excess) by MC-SIMS. As...
A Pb(Fe1/2Nb1/2)O3 ceramic sample was prepared through a high temperature solid-state reaction technique. The formation of single-phase perovskite compound confirmed by an x-ray diffraction Dielectric and impedance parameters were measured as function frequency (102–106 Hz) at different temperatures (28–200 °C). results described using equivalent circuit model extending the universal capacitor concept introduced Jonscher. Bulk permittivity material power law exponent (extracted from data)...
One of the main issues for operation LHC accelerator at CERN is field errors generated by persistent and coupling currents in dipoles injection conditions, i.e., 0.54 T dipole field. For this reason we are conducting systematic magnetic measurements to quantify above effects compare them expected values from measurement on strands cables. We discuss results terms DC current magnetization, AC with short time constant strand cable currents, long-term decay during excitation. Average spread...
Structural and Optical properties of the (Na0.5 K0.5)y Li 1-y NbO3 (y = 0.934 & 0.936) ceramics have been explored in terms X-Ray diffraction patters, Rietveld analysis, UV-Vis spectroscopy, Kubelka-Munk functions. analysis both these structures reveals them to be tetragonal with space group P4mm. It is found that increase doping increases optical band gap. Presence additional hardening dopant MnO2 a uniform behavior for composition. With increasing concentration, gap decreases indicative...
Presence of 60 Fe in early Solar System was established more than two decades ago, but the initial ratio Fe/ 56 is, still, not well constrained.Isotopic studies bulk meteorites samples from differentiated meteorites, achondrites, and chondrules suggest a low value ~2×10 -8 , while in-situ using secondary ion mass spectrometer much higher ~7×10 -7 .
Petrographic and quantitative analyses of more than 70 refractory inclusions found in the studied thin section Yamato 81020 (CO3.05)showed diverse objects that can be grouped into five distinct types based on morphology mineralogy.Mineralogical, textural similarities to pristine carbonaceous vigarano (3.1-3.4)types Efremovka, Vigarano were observed despite their smaller size (~100 micron diameter).Wark-Lovering rims predominantly melilite-rich calcium, aluminum-rich inclusions.Comparison...