George D. Cody
A5081902176- Astro and Planetary Science
- Isotope Analysis in Ecology
- Planetary Science and Exploration
- High-pressure geophysics and materials
- Glass properties and applications
- Advanced NMR Techniques and Applications
- Astrophysics and Star Formation Studies
- NMR spectroscopy and applications
- Thin-Film Transistor Technologies
- Geological and Geochemical Analysis
- Hydrocarbon exploration and reservoir analysis
- Nuclear Physics and Applications
- Methane Hydrates and Related Phenomena
- Silicon and Solar Cell Technologies
- Origins and Evolution of Life
- Superconducting Materials and Applications
- Paleontology and Stratigraphy of Fossils
- Silicon Nanostructures and Photoluminescence
- Physics of Superconductivity and Magnetism
- Granular flow and fluidized beds
- Mineral Processing and Grinding
- Spacecraft and Cryogenic Technologies
- Crystallography and molecular interactions
- Space Exploration and Technology
- Coal Properties and Utilization
Carnegie Institution for Science
2016-2025
Geophysical Laboratory
2012-2021
University of Oxford
2018
University of Arizona
2017
Rutgers, The State University of New Jersey
2000-2009
Bainbridge State College
2009
Rütgers (Germany)
2009
Rutgers Sexual and Reproductive Health and Rights
2009
University of Washington Tacoma
2009
Seoul National University
2008
The effect of thermal and structural disorder on the electronic structure hydrogenated amorphous silicon is investigated by measurement shape optical absorption edge as a function temperature evolution hydrogen. data are consistent with idea that additive, suggest disorder, rather than hydrogen content, fundamental determining factor in band gap.
The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. preliminary examination these samples shows that the nonvolatile portion is an unequilibrated assortment materials have both presolar solar system origin. contains abundance silicate grains are much larger than predictions interstellar grain models, many high-temperature minerals appear formed in inner regions nebula. Their presence a proves formation included...
The detailed balance method for calculating the radiative recombination limit to performance of solar cells has been extended include free carrier absorption and Auger in addition losses. This applied crystalline silicon where limiting efficiency is found be 29.8 percent under AM1.5, based on measured optical spectrum published values coefficients. assumed textured maximum benefit from light-trapping effects.
We adopt a statistical mechanical approach toward the optics of textured and inhomogeneous optical sheets. As general rule, local light intensity in such medium will tend to be <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2 n^{2}(x)</tex> times greater than externally incident intensity, where xmlns:xlink="http://www.w3.org/1999/xlink">n(x)</tex> is index refraction sheet. This enhancement can contribute...
Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, sulfides, amorphous material, trioctahedral smectites. smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. Cumberland both ~13.2 angstroms. larger suggests a partially chloritized magnesium facilitating H2O retention. Basaltic minerals...
Optical, electrical, and electron-microscopy studies on granular Ag-Si${\mathrm{O}}_{2}$ Au-Si${\mathrm{O}}_{2}$ films, prepared by cosputtering the metal insulator, were made over composition range 10-90% volume Si${\mathrm{O}}_{2}$. Electron diffraction patterns indicate crystalline metals with lattice constants equal to those of bulk metals. For films less than 50-vol% Si${\mathrm{O}}_{2}$ structure consists amorphous inclusions in a continuous matrix; for more Si${\mathrm{O}}_{2}$,...
The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of cosmic ray and energetic particle radiation environment surface 7 August 2012. We report discuss absorbed dose equivalent from galactic rays solar particles martian for ~300 days observations during current maximum. These provide insight into hazards associated with a human mission to an anchor point which model subsurface environment, implications microbial survival...
Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution abundance composition. Some organics are similar, but not identical, to those interplanetary dust particles carbonaceous meteorites. A class of aromatic-poor organic material is also present. The rich oxygen nitrogen compared with meteoritic organics. Aromatic compounds present, the tend be relatively poorer aromatics than meteorites particles. presence deuterium nitrogen-15 excesses suggest that...
Experiments exploring the potential catalytic role of iron sulfide at 250°C and elevated pressures (50, 100, 200 megapascals) revealed a facile, pressure-enhanced synthesis organometallic phases formed through reaction alkyl thiols carbon monoxide with sulfide. A suite compounds were characterized ultraviolet-visible Raman spectroscopy. The natural such is anticipated in present-day ancient environments wherever reduced hydrothermal fluids pass sulfide–containing crust. Here, pyruvic acid...
Samples from the Rocknest aeolian deposit were heated to ~835°C under helium flow and evolved gases analyzed by Curiosity’s Sample Analysis at Mars instrument suite. H 2 O, SO , CO O major released. Water abundance (1.5 3 weight percent) release temperature suggest that is bound within an amorphous component of sample. Decomposition fine-grained Fe or Mg carbonate likely source much . Evolved coincident with Cl, suggesting oxygen produced thermal decomposition oxychloride compound. Elevated...
Volume mixing and isotope ratios secured with repeated atmospheric measurements taken the Sample Analysis at Mars instrument suite on Curiosity rover are: carbon dioxide (CO2), 0.960(±0.007); argon-40 ((40)Ar), 0.0193(±0.0001); nitrogen (N2), 0.0189(±0.0003); oxygen, 1.45(±0.09) × 10(-3); monoxide, < 1.0 (40)Ar/(36)Ar, 1.9(±0.3) 10(3). The (40)Ar/N2 ratio is 1.7 times greater (40)Ar/(36)Ar 1.6 lower than values reported by Viking Lander mass spectrometer in 1976, whereas other are generally...
The Mars Science Laboratory rover Curiosity scooped samples of soil from the Rocknest aeolian bedform in Gale crater. Analysis with Chemistry and Mineralogy (CheMin) x-ray diffraction (XRD) instrument revealed plagioclase (~An57), forsteritic olivine (~Fo62), augite, pigeonite, minor K-feldspar, magnetite, quartz, anhydrite, hematite, ilmenite. phases are present at, or near, detection limits. also contains 27 ± 14 weight percent amorphous material, likely containing multiple Fe 3+ -...
H 2 O, CO , SO O S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, amorphous materials. Thermal decomposition carbonates combustion organic materials are candidate sources for . Concurrent evolution hydrocarbons suggests presence oxychlorine phase(s). Sulfides likely...
Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters diameter) and sand grains with textures typical fluvial sedimentary conglomerates. Rounded conglomerates indicate substantial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent minimal aqueous alteration sediments. Sediment was mobilized ancient water flows that likely exceeded threshold...
Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved an approximately average martian crustal composition to one influenced alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion deposition. The absence predicted geochemical variations indicates magnetite phyllosilicates formed diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous...
ABSTRACT We examined the chemical composition of extracellular polymeric substances (EPS) extracted from two natural microbial pellicle biofilms growing on acid mine drainage (AMD) solutions. The EPS obtained a mid-developmental-stage biofilm (DS1) and mature (DS2) were qualitatively quantitatively compared. More than twice as much was derived DS2 DS1 (approximately 340 150 mg per g [dry weight] for DS1, respectively). Composition analyses indicated presence carbohydrates, metals, proteins,...
The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal types along Curiosity rover traverse: a fine-grained mafic type and locally derived, coarse-grained felsic type. component is representative of widespread soils similar in composition to dust. It possesses ubiquitous hydrogen signature spectra, corresponding hydration amorphous phases found by CheMin instrument. This likely accounts for an important fraction global...
Significance We present data supporting the presence of an indigenous source fixed nitrogen on surface Mars in form nitrate. This may indicate first stage development a primitive cycle ancient and would have provided biochemically accessible nitrogen.
Samples of the carbonaceous asteroid (162173) Ryugu were collected and brought to Earth by Hayabusa2 spacecraft. We investigated macromolecular organic matter in samples found that it contains aromatic aliphatic carbon, ketone, carboxyl functional groups. The spectroscopic features are consistent with those chemically primitive chondrite meteorites experienced parent-body aqueous alteration (reactions liquid water). morphology carbon includes nanoglobules diffuse associated phyllosilicate...
Abstract On September 24, 2023, NASA's OSIRIS‐REx mission dropped a capsule to Earth containing ~120 g of pristine carbonaceous regolith from Bennu. We describe the delivery and initial allocation this asteroid sample introduce its bulk physical, chemical, mineralogical properties early analyses. The is very dark overall, with higher‐reflectance inclusions particles interspersed. Particle sizes range submicron dust stone ~3.5 cm long. Millimeter‐scale larger stones typically have hummocky or...
Organic matter in meteorites reveals clues about early Solar System chemistry and the origin of molecules important to life, but terrestrial exposure complicates interpretation. Samples returned from B-type asteroid Bennu by Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer mission enabled us study pristine carbonaceous astromaterial without uncontrolled Earth's biosphere. Here we show that samples are volatile rich, with more carbon, nitrogen ammonia than...