A5052209191- High-pressure geophysics and materials
- Geological and Geochemical Analysis
- Diamond and Carbon-based Materials Research
- earthquake and tectonic studies
- Methane Hydrates and Related Phenomena
- Nuclear Materials and Properties
- X-ray Diffraction in Crystallography
- Advanced Materials Characterization Techniques
- Metallurgical Processes and Thermodynamics
- nanoparticles nucleation surface interactions
- Hydrogen embrittlement and corrosion behaviors in metals
- Geochemistry and Geologic Mapping
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Geomagnetism and Paleomagnetism Studies
- Phase Equilibria and Thermodynamics
- Geological Studies and Exploration
- Electronic and Structural Properties of Oxides
- Mechanical and Optical Resonators
- Hydrocarbon exploration and reservoir analysis
- Metal and Thin Film Mechanics
- Geophysics and Gravity Measurements
- Crystal Structures and Properties
- Rare-earth and actinide compounds
- Advanced X-ray Imaging Techniques
Case Western Reserve University
2015-2025
Los Alamos National Laboratory
2018-2023
University of Edinburgh
2023
Deutsches Elektronen-Synchrotron DESY
2023
The Ohio State University
2009-2018
Abstract Combined synthesis experiments and first‐principles calculations show that MgSiO 3 ‐perovskite with minor Al or Fe does not incorporate significant OH under lower mantle conditions. Perovskite, stishovite, residual melt were synthesized from natural Bamble enstatite samples (Mg/(Fe + Mg) = 0.89 0.93; 2 O < 0.1 wt % 35 2065 ppm weight H O, respectively) in the laser‐heated diamond anvil cell at 1600–2000 K 25–65 GPa. Fourier transform infrared spectroscopy, X‐ray diffraction, ex...
Chemical separations are costly in terms of energy, time, and money. Separation methods optimized with inefficient trial-and-error approaches that lack insight into the molecular dynamics lead to success or failure a separation and, hence, ways improve process. We perform super-resolution imaging fluorescent analytes five different commercial liquid chromatography materials. Unexpectedly, we observe chemical functionalization can block more than 50% material’s porous interior, rendering it...
Silica is thought to be present in the Earth’s lower mantle subducting plates, addition being a prototypical solid whose physical properties are of broad interest. It known undergo phase transition from stishovite CaCl2-type structure at ~50–80 GPa, but exact location and slope boundary pressure-temperature space unresolved. There have been many previous studies on equation state stishovite, they span limited range pressures temperatures, there has no thermal SiO2 measured under static...
The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument European Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located multipurpose vacuum chamber. Concepts pump–probe experiments DAC are described their implementation demonstrated during First User Community Assisted Commissioning experiment. heating Bi under pressure, obtained using 20...
Abstract The viscosity of Earth’s lower mantle is poorly constrained due to the lack knowledge on some fundamental variables that affect deformation behaviour its main mineral phases. This study focuses bridgmanite, constituent, and assesses rheology by developing an approach based physics. Following revising recent advances in this field, pure climb creep controlled diffusion identified as key mechanism driving bridgmanite. strain rates phase under pressures, temperatures stresses are thus...
The proportions of oxygen, carbon and major rock-forming elements (e.g. Mg, Fe, Si) determine a planet's dominant mineralogy. Variation in mineralogy subsequently affects planetary mantle dynamics as well any deep water or cycle. Through thermodynamic models high pressure diamond anvil cell experiments, we demonstrate the oxidation potential C is above that Fe at all pressures temperatures indicative 0.1 - 2 Earth-mass planets. This means for planet with (Mg+2Si+Fe+2C)/O > 1, excess will be...
Multiple substitution mechanisms for hydrogen in γ-(Mg,Fe)2SiO4, ringwoodite, lead to broad, overlapping, and difficult-to-interpret FTIR spectra. Through combined low-temperature, high-pressure synchrotron-based spectroscopy, the multiple bonding sites become evident, can be traced as a function of temperature compression. OH stretching bands resolved iron-bearing iron-free samples with 0.79-2.5(3) wt% H2O below 200 K at ambient pressure, cooling 5 35 23 GPa resulting resolution possibly...
The ultrafast synthesis of ε-Fe3N1+x in a diamond-anvil cell (DAC) from Fe and N2 under pressure was observed using serial exposures an X-ray free electron laser (XFEL). When the sample at 5 GPa irradiated by pulse train separated 443 ns, estimated temperature delay time above 1400 K, confirmed situ transformation α- to γ-iron. Ultimately, reacted uniformly throughout beam path form Fe3N1.33, as deduced its established equation state (EOS). We thus demonstrate that activation energy provided...
Experiments accessing extreme conditions at x-ray free electron lasers (XFELs) involve rapidly evolving of temperature. Here, we report time-resolved, direct measurements temperature using spectral streaked optical pyrometry and laser-heated states the High Energy Density instrument European XFEL. This collection typical experiments, coupled with numerical models, outlines reliability, precision, meaning time dependent emission XFEL sources. Dynamic temperatures above 1500 K are measured...
Abstract A reflector 70–130 km below the base of transition zone beneath Tibet is observed in receiver functions and underside seismic reflections, at depths consistent with garnet to bridgmanite. Contrast water storage capacity between minerals Earth's lower mantle suggests possibility for dehydration melting top mantle. First‐principles calculations combined laboratory synthesis experiments constrain across into We interpret signal as 3–4 vol % hydrous melt resulting from bridgmanite...
In this report, we present results of high-pressure experiments probing the melt line zirconium (Zr) up to 37 GPa. This investigation has determined that temperature versus laser power curves provide an accurate method determine temperatures. When information is combined with onset diffuse scattering, which associated process, demonstrate ability accurately boundary. presents a reliable for rapid determination boundary and agrees well other established techniques such measurements, as...
Abstract We have fabricated novel controlled‐geometry samples for the laser‐heated diamond‐anvil cell (LHDAC) in which a transparent oxide layer (SiO 2 ) is sandwiched between two laser‐absorbing layers (Ni) single, cohesive sample. The were mass manufactured (>10 4 samples) using combination of physical vapor deposition, photolithography, and wet plasma etching. double hot‐plate arrangement samples, coupled with chemical spatial homogeneity layers, addresses problems temperature...
Interpretation of lateral variations in upper mantle seismic wave speeds requires constraints on the relationship between elasticity and water concentration at high pressure for all major minerals, including garnet component. We have calculated structure energetics charge-balanced hydrogen substitution into tetragonal MgSiO3 majorite up to P = 25 GPa using both classical atomistic simulations complementary first-principles calculations. At conditions Earth's transition zone, hydroxyl groups...
The isothermal compression of transition metal tantalum (Ta) was studied in a diamond anvil cell by X-ray diffraction utilizing rhenium (Re) and gold (Au) as internal pressure standards. Re marker employed during non-hydrostatic to pressures up 310 GPa while the Au used quasi-hydrostatic neon pressure-transmitting medium 80 GPa. Two ultra-high experiments were conducted on Ta mixtures focused-ion beam machined toroidal anvils with central flats varying from 8 microns 16 diameter. observed be...
Polyethylene (C2H4)n was compressed to pressures between 10 and 30 GPa in a diamond anvil cell (DAC) laser heated above 2500 K for approximately one second. This resulted the chemical decomposition of polymer into carbon hydrocarbon reaction products. After quenching ambient temperature, products were measured DAC at ranging from 29 using combination x-ray diffraction (XRD) small angle scattering (SAXS). XRD identified cubic methane as predominant product species with their pressure-volume...
Zirconium (Zr) has properties conducive to nuclear applications and exhibits complex behavior at high pressure with respect the effects of impurities, deviatoric stress, kinetics, grain growth which makes it scientifically interesting. Here, we present experimental results on 300 K equation state ultra-high purity Zr obtained using diamond-anvil cell coupled synchrotron-based x-ray diffraction electrical resistance measurements. Based quasi-hydrostatic room-temperature compression in helium...
Tantalum (Ta) is a metal that has useful properties make it in extreme environments. It is, therefore, important to understand how Ta performs such conditions by accurately measuring its properties. In this work, the yield strength of tantalum been measured at pressures up 276 GPa using axial and radial x-ray diffraction (XRD) methods diamond anvil cells (DACs). We XRD DAC 50 GPa, an 60 diamonds with standard flat culets, final experiment toroidal anvils. The data were refined Material...
The pioneering of x-ray diffraction with in situ laser heating the diamond-anvil cell has revolutionized field high-pressure mineral physics, expanding ability to determine high-pressure, high-temperature phase boundaries and equations state. Accurate determination phases densities rely upon collinearity beam center laser-heated spot. We present development microfabricated samples that, by nature their design, will have sample interest hottest portion sample. report initial successes a...
Earth's mantle convection is powered in part by the radiogenic heat released decay of 238U, 235U, 232Th, and 40K. We present ab initio calculations uranium thorium incorporation CaSiO3-perovskite with without aluminum, propose that aluminous calcium silicate perovskite likely host lower mantle. At 15 GPa, enthalpies solution into aluminum-free are 10.34 kJ/mol for U4+ 12.52 Th4+ SiO2 saturated systems, while 17.09 19.27 kJ/mol, respectively, CaO systems. Coupled substitution aluminum...
Many rutile-type materials are characterized by a softness in shear with pressure which is coupled to Raman-active librational motion. Combining direct studies of anion positions SnO2 measurements its electronic properties, we find correlation between O sublattice disorder 5 and 10 GPa an anomalous decrease up 4 orders magnitude electrical resistance. Hypotheses into the atomistic nature phenomenon evaluated via ab initio calculations guided extended X-ray absorption fine structure...
Constraining the spin state of Fe in Earth's lower mantle is critical to understanding chemistry and dynamics interior. In October 2015 issue American Mineralogist, Dorfman et al. present an experimental study effect iron concentration on transition bridgmanite. Their experiments involved two different bridgmanite compositions (38 74% FeSiO3). Based total moment determined by synchrotron-based X-ray emission spectroscopy, they show that Fe2+ high-spin but pressure decreases within highly...
We present a portable CO2 laser heating system for in situ x-ray absorption spectroscopy (XAS) studies at 16-BM-D (High Pressure Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory). Back scattering optical measurements are made possible by the implementation of Ge beamsplitter. Optical pyrometry is conducted near-infrared, and our temperature free chromatic aberration due to peak-scaling method [A. Kavner W. R. Panero, Phys. Earth Planet. Inter. 143–144, 527–539...