A5023729183- Planetary Science and Exploration
- Radioactive element chemistry and processing
- Geochemistry and Geologic Mapping
- Iron oxide chemistry and applications
- Minerals Flotation and Separation Techniques
- Geochemistry and Elemental Analysis
- Paleontology and Stratigraphy of Fossils
- Groundwater and Isotope Geochemistry
- Geological and Geochemical Analysis
- Hydrocarbon exploration and reservoir analysis
- Metal Extraction and Bioleaching
- Geology and Paleoclimatology Research
- Clay minerals and soil interactions
- Astro and Planetary Science
- Mine drainage and remediation techniques
- earthquake and tectonic studies
- Calcium Carbonate Crystallization and Inhibition
- Geotechnical and Geomechanical Engineering
- Bladed Disk Vibration Dynamics
- Granular flow and fluidized beds
- Bone Tissue Engineering Materials
- Geophysical and Geoelectrical Methods
- High-pressure geophysics and materials
- Environmental remediation with nanomaterials
- Arsenic contamination and mitigation
University of Oklahoma
2015-2025
Noble Research Institute
2025
Weatherford College
2024
University of Sheffield
2018-2024
Ansys (United States)
2020-2024
Michigan United
2021-2024
Norman Regional Hospital
2014-2016
ConocoPhillips (United States)
2013
New York University
2012
University of Michigan
2009-2012
Using Fourier Transform InfraRed (FTIR) spectroscopy, Raman X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM), we characterize the structure and/or morphology of hematite (α-Fe2O3) particles with sizes 7, 18, 39 120 nm. It is found that these nanoparticles possess maghemite (γ-Fe2O3)-like defects in near surface regions, to which a vibrational mode at 690 cm−1, active both FTIR spectra, assigned. The fraction maghemite-like net lattice disorder are inversely related...
Manganese (Mn) oxides are among the most reactive sorbents and oxidants within environment, where they play a central role in cycling of nutrients, metals, carbon. Recent discoveries have identified superoxide ([Formula: see text]) both biogenic abiogenic origin as an effective oxidant Mn(II) leading to formation Mn oxides. Here we examined conditions under which abiotically produced led oxidative precipitation solid-phases produced. Oxidized Mn, aqueous Mn(III) Mn(III/IV) oxides, was only...
Deviations to the cyclic symmetry of turbomachinery blisks are common due manufacturing, general wear, or foreign object damage. These deviations, called mistuning, can lead dramatically increased forced responses a few blades. The high computational cost associated with predictions for mistuned has led development various reduced-order modeling techniques. This paper introduces new approach both large and small mistuning. makes use pristine-rogue-interface modal expansion (PRIME). PRIME...
Research Article| July 01, 2013 Dynamic weakening by nanoscale smoothing during high-velocity fault slip Xiaofeng Chen; Chen 1School of Geology and Geophysics, University Oklahoma, Norman, Oklahoma 73019, USA Search for other works this author on: GSW Google Scholar Andrew S. Madden; Madden Barry R. Bickmore; Bickmore 2Department Geological Sciences, Brigham Young University, Provo, Utah 84602, Ze'ev Reches * *E-mail: reches@ou.edu. Author Article Information Publisher: Society America...
In the field of thin-layer-structured inorganic nanotubes, morphological, structural, and chemical/physical modifications induced in synthetic stoichiometric chrysotile nanotubes have been evaluated as a function extent Fe doping. Fe-doped nanocrystals obtained range from 0.29 wt.-% up to 1.37 Fe. A partial replacement for Si Mg has observed through modification Fourier-transform infrared (FTIR) absorption bands. FTIR spectroscopic, X-ray diffraction, thermogravimetric analyses provide...
Research Article| February 01, 2013 Effect of Fly Ash on the Behavior Expansive Soils: Microscopic Analysis BOTAO LIN; LIN School Civil Engineering and Environmental Science, University Oklahoma, Norman, OK 73019 Search for other works by this author on: GSW Google Scholar AMY B CERATO; CERATO 1 1Corresponding email: acerato@ou.edu. ANDREW S MADDEN; MADDEN ConocoPhillips Geology Geophysics, 70319 MEGAN E ELWOOD Author Article Information Publisher: Association & Geologists First Online: 02...
Research Article| July 01, 2009 How long was Meridiani Planum wet? Applying a jarosite stopwatch to determine the duration of aqueous diagenesis Megan E. Elwood Madden; Madden 1School Geology and Geophysics, University Oklahoma, 100 Boyd Street, Suite 810, Norman, Oklahoma 73019, USA Search for other works by this author on: GSW Google Scholar Andrew S. J. Donald Rimstidt 2Department Geosciences, Virginia Tech, 4044 Derring Hall, Blacksburg, 24061, (2009) 37 (7): 635–638....
Conventional flat plate‐shaped brushite, dicalcium phosphate dihydrate, CaHPO 4 ·2 H 2 O ), produced by reacting Ca ‐chloride and alkali salt solutions, were found to undergo a maturation process (changing their / P molar ratio from 0.8 the theoretical value of 1) similar those seen in biological apatites. Water lily ( WL )‐shaped brushite crystals nonstirred aqueous solutions at room temperature 24 h, using precipitated calcite NH PO as starting chemicals. The hydrothermal transformation...
While environmental biofilms have recently been implicated as a potential major sink for nanoparticles (NPs), the mechanisms of interactions remain largely unknown.
This study investigates the use of thermogravimetry (TG) and X-ray diffraction (XRD) to characterize quantify hydration products, particularly calcium silicate hydrate (CSH) hydroxide [Ca(OH)2], in stabilized soils establish correlations between these products strength gain over time. A pure kaolinite is soil for this portland cement selected stabilizer. Untreated cement-stabilized samples are compacted at their optimum conditions cured different periods up 90 days. The unconfined...
Hexavalent chromium (Cr(vi), present predominantly as CrO4(2-) in water at neutral pH) is a common ground pollutant, and reductive immobilization frequent remediation alternative. The Cr(iii) that forms upon microbial or abiotic reduction often co-precipitates with naturally added iron (Fe), the stability of resulting Fe-Cr precipitate function its mineral properties. In this study, solids were formed by Cr(vi) using Desulfovibrio vulgaris strain RCH1 presence Fe-bearing minerals hematite,...
Research Article| September 01, 2005 Earth's Nano-Compartment for Toxic Metals Michael F. Hochella, Jr.; Jr. 1NanoGeoscience and Technology Laboratory Department of Geosciences, Virginia Tech Blacksburg, VA 24041-0420, USA E-mail: hochella@vt.edu Search other works by this author on: GSW Google Scholar Andrew S. Madden hochella@vt.edu2Present address: Environmental Sciences Division Oak Ridge National P.O. Box 2008 Ridge, TN 37831-6036, Author Article Information Publisher: Mineralogical...