A5035018361- Hydrocarbon exploration and reservoir analysis
- Geological and Geochemical Analysis
- Hydraulic Fracturing and Reservoir Analysis
- CO2 Sequestration and Geologic Interactions
- Iron oxide chemistry and applications
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Enhanced Oil Recovery Techniques
- Minerals Flotation and Separation Techniques
- Mineralogy and Gemology Studies
- Calcium Carbonate Crystallization and Inhibition
- Clay minerals and soil interactions
- Phase Equilibria and Thermodynamics
- Groundwater flow and contamination studies
- Chemical and Physical Properties in Aqueous Solutions
- Geology and Paleoclimatology Research
- Building materials and conservation
- NMR spectroscopy and applications
- Geochemistry and Geologic Mapping
- Radioactive element chemistry and processing
- Crystallization and Solubility Studies
- Electrostatics and Colloid Interactions
- Methane Hydrates and Related Phenomena
- Archaeology and ancient environmental studies
- Hydrogen Storage and Materials
Oak Ridge National Laboratory
2015-2024
University of Tennessee at Knoxville
2004-2020
Fermi National Accelerator Laboratory
2020
Knoxville College
2012-2020
Pacific Northwest National Laboratory
2019
University of Manitoba
2019
Oak Ridge Associated Universities
2018
NIST Center for Neutron Research
2007-2018
National Institute of Standards and Technology
2007-2018
Physical Sciences (United States)
2017
Porosity plays a clearly important role in geology. It controls fluid storage aquifers, oil and gas fields geothermal systems, the extent connectivity of pore structure control flow transport through geological formations, as well relationship between properties individual minerals bulk rock. In order to quantify relationships porosity, storage, rock properties, however, must be measured quantitatively described. The overall importance at least with respect use rocks building stone was...
Abstract Fracture pattern development has been a challenging area of research in the Earth sciences for more than 100 years. Much learned about spatial and temporal complexity inherent to these systems, but severe challenges remain. Future advances will require new approaches. Chemical processes play larger role opening‐mode fracture hitherto appreciated. This review examines relationships between mechanical geochemical that influence patterns recorded natural settings. For fractures formed...
A comprehensive picture of the interface between aqueous solutions and (110) surface rutile (α-TiO2) is being developed by combining molecular-scale macroscopic approaches, including experimental measurements, quantum calculations, molecular simulations, Gouy−Chapman−Stern models. In situ X-ray reflectivity standing-wave measurements are used to define atomic arrangement adsorbed ions, coordination interfacial water molecules, substrate termination structure. Ab initio calculations dynamics...
Experimental data on phase relations in the CaCO3-MgCO3-FeCO3 ternary by Goldsmith et al. (1962) are inconsistent with those of Rosenberg (1967). These inconsistencies cannot be reconciled pressure or temperature differences between two sets experiments. Available reversed experiments binary systems have been re-evaluated to yield consistent solvi. combined analyses natural carbonates approximate diagrams at 250,400,550, and 700 °C, 4 model activity/composition for calcite-...
Small angle neutron scattering (SANS) and scanning transmission electron microscopy (STEM) were used to study film formation by magnesium alloys AZ31B (Mg-3Al-1Zn base) ZE10A (Elektron 717, E717: Mg-1Zn + Nd, Zr) in H2O D2O with without 1 or 5 wt% NaCl. No SANS changes observed after 24 h exposures compared as-received (unreacted) alloy, consistent relatively dense MgO-base formation. However, exposure NaCl resulted accelerated corrosion, resultant detected. The data indicated both particle...
Molecular dynamics (MD) simulations of 1-alkyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([CnMPy][Tf2N], n = 3, 4, 6, 8, 10) were conducted using an all-atom model. Radial distribution functions (RDF) computed and structure generated to compare with new X-ray scattering experimental results, reported herein. The peaks in the generally shift lower Q values increased temperature for all liquids this series. However, first sharp diffraction peak (FSDP) longer alkyl chain displays...
Using neutron scattering and ab initio simulations, we document the discovery of a new "quantum tunneling state" water molecule confined in 5 Å channels mineral beryl, characterized by extended proton electron delocalization. We observed number peaks inelastic spectra that were uniquely assigned to quantum tunneling. In addition, momentum distribution was measured with deep scattering, which directly revealed coherent delocalization protons ground state.Received 18 November...
Boehmite (γ-AlOOH) and gibbsite (α-Al(OH)3) are important archetype (oxy)hydroxides of aluminum in nature that also play diverse roles across a plethora industrial applications. Developing the ability to understand predict properties characteristics these materials, on basis their natural growth or synthesis pathways, is an fundamental science enterprise with wide-ranging impacts. The present study describes bulk surface novel materials comprehensive detail, using collectively sophisticated...
Quasielastic neutron scattering (QENS) experiments carried out using time-of-flight and backscattering spectrometers with widely different energy resolution dynamic range revealed the diffusion dynamics of hydration water in nanopowder rutile (TiO2) cassiterite (SnO2) that possess crystal structure (110) face predominant on surface. These isostructural oxides differ their bulk dielectric constants, metal atom electronegativities, lattice spacings, which may all contribute to differences...
To constrain the tectonic and metamorphic history of Grenville Province southern Ontario we have quantitatively evaluated changes in peak pressures temperatures region. Pressures increase northwest from Frontenac Axis towards Front, they 4–6 kb near Madoc to 10–11 south North Bay. Further north decrease 8–9 Front Tectonic Zone French Mattawa Rivers. Temperatures form a broad high, reaching 800°C northeast Parry Sound, decreasing 400–500°C Hastings Low Madoc, 600–650°C east Ottawa River,...
Induced mineral precipitation is potentially important for the remediation of contaminants, such as during trapping carbon or toxic metal sequestration. The prediction reactions complicated by porous nature rocks and soils their interaction with precipitate, introducing transport confinement effects. Here X-ray scattering measurements, modeling, electron microscopies were used to measure kinetics calcium carbonate in a amorphous silica (CPG) that contained two discrete distributions pore...
The structure of SnO2 nanoparticles (avg. 5 nm) with a few layers water on the surface has been elucidated by atomic pair distribution function (PDF) methods using in situ neutron total scattering data and molecular dynamics (MD) simulations. Analysis PDF, prompt gamma, thermogravimetric data, coupled MD-generated D2O/OD configurations demonstrates that minimum concentration OD groups required to prevent rapid growth during thermal dehydration corresponds ~0.7 monolayer coverage. Surface...
Although oriented aggregation of particles is a widely recognized mechanism crystal growth, the impact many fundamental parameters, such as crystallographically distinct interfacial structures, solution composition, and nanoparticle morphology, on governing mechanisms assembly kinetics are largely unexplored. Thus, collective dynamics systems exhibiting OA has not been predicted. In this context, we investigated structure boehmite function pH ionic strength. Cryogenic transmission electron...