A5035480573- Astro and Planetary Science
- Planetary Science and Exploration
- High-pressure geophysics and materials
- Lubricants and Their Additives
- Hydrocarbon exploration and reservoir analysis
- Gear and Bearing Dynamics Analysis
- Astrophysics and Star Formation Studies
- Force Microscopy Techniques and Applications
- Petroleum Processing and Analysis
- Enhanced Oil Recovery Techniques
- Advanced Chemical Physics Studies
- Cultural Heritage Materials Analysis
- Isotope Analysis in Ecology
- Maritime and Coastal Archaeology
- Conservation Techniques and Studies
- Chemical Analysis and Environmental Impact
- Molecular Spectroscopy and Structure
- Geological and Geochemical Analysis
- Solid-state spectroscopy and crystallography
- Microbial Community Ecology and Physiology
- Magnetic and Electromagnetic Effects
- Quantum, superfluid, helium dynamics
- Spaceflight effects on biology
- Geology and Paleoclimatology Research
- Porphyrin and Phthalocyanine Chemistry
Natural History Museum
2020-2025
Lawrence Livermore National Laboratory
2005-2024
Imperial College London
2013-2021
Imperial Valley College
2011
Paul Scherrer Institute
2010
University of Bristol
2010
University of California, Berkeley
2005-2008
Planetary Science Institute
2008
Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant dead cells. Although biomass and diversity decrease with increasing aridity the Atacama Desert, we provide multiple lines evidence for presence at times metabolically active, one driest places We base this observation four major evidence: (i)...
We report Raman, infrared, and x-ray diffraction (XRD) measurements, along with ab initio calculations on formic acid (FA) under pressure up to 50 GPa. find an infinite chain $Pna{2}_{1}$ structure be a high-pressure phase at room temperature. Our data indicate the symmetrization partially covalent character of intrachain hydrogen bonds above approximately 20 Raman spectra XRD patterns loss long-range order pressures 40 GPa, large hysteresis upon decompression. attribute this behavior...
Low-friction lubricant formulations are urgently needed to improve the energy efficiency of machines. Here, we show that blending 1-dodecanol with a hydrocarbon oil improves lubrication in non-conformal sliding/rolling contacts by simultaneously increasing hydrodynamic film thickness and reducing viscous friction. This is due pressure-induced polymorphic phase transformations molecules after they flow through thickness-determining inlet reach load-supporting zone. At relatively low...
The detection of chlorinated hydrocarbons by Curiosity on Mars has been attributed to the presence unidentified indigenous organic matter. Similarly, oxychlorines Earth have proposed be responsible for apparent lack organics in Atacama Desert. perchlorate (ClO4-) poses a unique challenge measurement matter due oxidizing power during commonly used pyrolysis-gas chromatography-mass spectrometry (py-GC-MS) methods. Here, we show that perchlorates and other oxyanion salts inhibit compounds but...
Simple n-alcohols, such as 1-dodecanol, show anomalous film-forming and friction behaviors under elastohydrodynamic lubrication (EHL) conditions, found inside bearings gears. Using tribometer, diamond anvil cell (DAC), differential scanning calorimetry (DSC) experiments, we that liquid 1-dodecanol undergoes a pressure-induced solidification when entrained into EHL contacts. Different solid polymorphs are formed the contact depending on temperature pressure conditions. Surprisingly, at...
The conservation and characterization of preservation fluids are crucial for maintaining specimen integrity in natural history fluid collections. However, characterizing these analytically poses significant challenges, especially as noninvasive methods preferred to avoid opening jars reduce the risk compromising specimens. This proof-of-concept study investigates feasibility using a hand-held spatially offset Raman spectroscopy (SORS) instrument determine chemical composition through their...
Low-friction lubricant formulations are urgently needed to improve the energy efficiency of machines. Here, we show that blending 1-dodecanol with a hydrocarbon oil improves lubrication in nonconformal sliding/rolling contacts by simultaneously increasing hydrodynamic film thickness and reducing viscous friction. This is due pressure-induced polymorphic phase transformations molecules after they flow through film-thickness-determining inlet reach load-supporting zone. At relatively low...
Abstract Exceptional preservation of biogeochemical complexity in the Precambrian is largely limited to cherts, phosphates and shales; however, ancient fossils, including microbial mats microbially induced sedimentary structures, also occur, more rarely, poorly sorted, coarse-grained siliciclastics. The precise micromechanics by which exceptional retention organic traces occur within such rocks over billion-year geological timescales remain understood. Herein, we explore micro–nano-scale...
The infrared response of coronene (C24H12) under pressure and temperature conditions up to 10 GPa 300 °C is examined in situ using a diamond anvil cell synchrotron-source Fourier transform (FTIR) spectroscopy. Coronene polycyclic aromatic hydrocarbon that present the interstellar medium meteorites which may have contributed Earth's primordial carbon budget. It appears undergo reversible phase transition between 2 3.2 at ambient temperature; new intramolecular bonds region 840−880 cm−1 result...
Lycopodium sporopollenin, a natural copolymer, shows exceptional stability under high hydrostatic pressures (10 GPa) as determined by in situ pressure synchrotron source Fourier transform infrared spectroscopy. This is evaluated terms of the component compounds sporopollenin: p ‐coumaric acid, phloretic ferulic and palmitic sebacic acids, which represent additional n ‐acid ‐diacid components. attributed to interactions between these components, rather than any one molecular component. study...
Abstract Instruments on the Viking landers and Curiosity rover analyzed samples of Mars detected carbon dioxide organic compounds uncertain origin. Mineral‐assisted reactions are leading to uncertainty, particularly those involving perchlorate minerals which thermally decompose produce chlorine oxygen can then react with matter generate organochlorine dioxide. Although generally considered a problem for interpretation, release profiles generated gases indicate type present. We have performed...
We have determined the melting temperature of formic acid (HCOOH) as a function pressure to 8.5 GPa using infrared absorption spectroscopy, Raman spectroscopy and visual observation samples in resistively heated diamond-anvil cell. The experimentally incongruent curve compares favorably with two-phase thermodynamic model. Decomposition reactions were observed above up 6.5 GPa, principal products being CO2, H2O, CO. At pressures decomposition led reaction that could be quenched solids zero...
The majority of global petroleum is in the form highly viscous heavy oil. Traditionally oil sands at shallow depths accessed by large scale mining activities. Recently steam has been used to allow extraction with greatly reduced surface disturbance. However, situ thermal recovery processes can generate hydrogen sulphide, high levels which are toxic humans and corrosive equipment. Avoiding sulphide production best possible mitigation strategy. Here we use laboratory aquathermolysis reproduce...
Abstract Impact ejected rocks are targets for life detection missions to Mars. The Martian subsurface is more favourable organic preservation than the surface owing an attenuation of radiation and physical separation from oxidising materials with increasing depth. events bring where they may be accessed without complicated drilling procedures. On Earth, different assemblages matter types derived varying depositional environments. Here we assess whether these can survive impact corruption. We...
Abstract The search for life on Mars targets the detection of organic matter from extant or extinct organisms. Current protocols use thermal extraction procedures to transfer mass spectrometer detectors. Oxidizing minerals Mars, such as perchlorate, interfere with by extraction. Thermal decomposition perchlorate releases oxygen, which promotes combustion carbon. We have assessed minimum ratio carbon required detect and spectrometry. Locations ratios above 4.7–9.6 should be targeted. Because...
Abstract The production of gaseous sulfur-containing species during the steam-assisted recovery heavy oil and bitumen have important consequences for both economics safety. Factors such as effects mineral matrices require laboratory data to produce accurate models. To study on gas we studied a well-characterized oil-containing core isolated crude from that core. samples were run at 250–300°C in continued presence liquid water 24 hours. reaction products all experiments include gases,...
We have studied cyanuric acid (H(3)C(3)N(3)O(3)) at static pressures up to 8.1 GPa and simultaneous temperatures 750 K, using primarily infrared absorption spectroscopy visual observation. The corresponding phase diagram compares favorably with theoretical predictions of metastable organic materials. Two reactions were observed characterized; both are irreversible. Below 2 GPa, melting is accompanied by a decomposition reaction, upon cooling, not recovered. Above heating results in solid...
Abstract The production of gaseous sulfur-containing species during the steam-assisted recovery heavy oil and bitumen presents problems owing to their toxicity, corrosion properties odor. In order quantitatively study aquathermolysis sulfur chemistry thermal (steam-assisted) oils we have subjected a well-characterized sulfur-rich core sample 150 - 325°C 70 1740 psia (0.48 12 MPa) conditions in continued presence liquid water for 24 hours. reaction products include gases, flotate, sinkate,...
Heavy oil is recovered from reservoirs using steam-assisted technology, which can lead to H2S generation if the relatively sulfur-rich. We have used laboratory aquathermolysis simulate gravity drainage process and compared free heavy that contained within mineral matrix. The presence of a matrix was found affect amount produced chemical properties generated. Our findings show production initiated by naturally occurring minerals at specific temperatures pressures techniques avoid these...
There are a number of key structures that can be used to reveal the formation and modification history organic matter in cosmos. For instance, susceptibility heat is well documented relative thermal stabilities different isomers as cosmothermometers. Yet despite being an important variable, no previously recognized marker pressure exists. The absence unfortunate considering our ability effectively recognize extraterrestrial both remotely laboratory. wide variety pressures cosmic settings...
Abstract Three Mars missions have analyzed the composition of surface samples using thermal extraction techniques. The temperatures decomposition been used as diagnostic information for materials present. One compound great current interest is perchlorate, a relatively recently discovered component Mars' geochemistry that leads to deleterious effects on organic matter during extraction. Knowledge behavior perchlorate salts essential mineral identification and possible avoidance confounding...