Research Interests: Engineering, Materials Science, Thermodynamics, High Pressure, Gas Hydrate, and 15 moreMedicine, Scientific Instruments, Scientific, Process Simulation, Physical sciences, Time Resolved, Diamond Anvil cell, Distributed Sensing, CHEMICAL SCIENCES, Optical fiber, Fiber Optic, Large Scale, Pressure Vessel, High Spatial Resolution, and Shock Tube
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JH Schneibel, CJ Rawn, TR Watkins, and EA Payzant Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831. ... 11 CJ Rawn, JH Schneibel, CM Hoffmann, and CR Hubbard, Intermetallics 9, 209 2001 . ...
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Single crystals and powder samples of Ba4ZnTi11O27 and Ba2ZnTi5O13 have been synthesized and studied using single-crystal X-ray precession photographs and X-ray powder diffraction. Unit cell dimensions were calculated from a least-squares... more
Single crystals and powder samples of Ba4ZnTi11O27 and Ba2ZnTi5O13 have been synthesized and studied using single-crystal X-ray precession photographs and X-ray powder diffraction. Unit cell dimensions were calculated from a least-squares refinement with a final maximum Δ2θ of 0.05°. Both phases were found to have monoclinic cells, space group C2/m. The refined lattice parameters for the Ba4ZnTi11O27 compound are a= 19.8687(8) Å, b=11.4674(5) Å, c=9.9184(4) Å, β= 109.223(4)°, and Z=4. The refined lattice parameters for the Ba2ZnTi5O13 compound are a= 15.2822(7) Å, b=3.8977(1) Å, c=9.1398(3) Å, β=98.769(4)°, and Z=2.
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ABSTRACT Our previous research demonstrated that biosynthesized magnetite (biomagnetite) exhibited similar properties as chemically synthesized magnetite. To complement uses of the traditional chemically synthesized magnetite... more
ABSTRACT Our previous research demonstrated that biosynthesized magnetite (biomagnetite) exhibited similar properties as chemically synthesized magnetite. To complement uses of the traditional chemically synthesized magnetite (chem-magnetite) biomagnetite must be exhibit highly reproducible sizes and be available in scalable qualities. Here we emphasize potentially advantageous properties of biomagnetite regarding size, reproducibility and scaling availability. Average crystallite size (ACS) of biomagnetites ranging from 10-100 nm was determined after varied 1) incubation times, 2) substitution of metal and lanthanide species, 3) degrees of congruent incorporation or retardation of substitution elements, 4) bacterial species with their varied ability to substitute elemental species, and 6) incubation temperature that can influence coalescence. The microbial production of biomagnetite has demonstrated capacity to make highly crystalline nanoscale particles of metal-substituted ferrites including compounds of Co, Ni, Cr, Mn, Zn and the rare earths in large quantity. Selected Zn-substituted magnetite (nominal composition of Zn0.6Fe2.4O4) has been recovered at over 1 kg (wet weight) in batches from 30 L fermentations. The massively produced extracellular magnetites were confirmed to exhibit good mono- dispersity via transmission electron microscopy (TEM). TEM also validated highly reproducible ACS of 13.1±0.8 nm size as determined through X-ray diffraction (N=7) at a 99 % confidence level. Based on the scale-up experiments performed using the 35 L reactor, the reduction in ACS variability and shorted incubation times of several days may be attributed to increases of electron donor input, and availability of divalent ions of the substitution metal with less ferrous ions in the case of doped magnetite, or a combination of the above. While costs of commercial nanometer sized magnetite (25-50 nm) may vary from 500/kg to > 1,000/kg, microbial mass production is likely capable of producing 13-90 nm magnetite or doped magnetites at a fraction of the cost of traditional chemical synthesis. While there are numerous approaches for the synthesis of nanoparticles, bacterial fermentation of magnetite or metal-substituted magnetite may represent a disruptive manufacturing technology with respect to yield, reproducibility and scalability.
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... During this session, Kevin Rhodes, a graduate student from the University of Tennessee, was recognized as the Power Diffraction SIG's 2011 ... analysis Wednesday morning the M/N/P SIGs co-sponsored with the Canadian Division... more
... During this session, Kevin Rhodes, a graduate student from the University of Tennessee, was recognized as the Power Diffraction SIG's 2011 ... analysis Wednesday morning the M/N/P SIGs co-sponsored with the Canadian Division a tribute session honoring Lachlan Cranswick. ...
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... GA MILLER Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401, USA EA PAYZANT, CJ RAWN Metals and Ceramics Division, Oak Ridge National Laboratory §, Oak Ridge, Tennessee 37831, USA ...
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Research Interests: Engineering, Materials Science, Manufacturing, Materials, Scanning Electron Microscopy, and 13 moreTransmission Electron Microscopy, Fabrication, Activation Energy, Thermogravimetry, CHEMICAL SCIENCES, High Resolution, Thermal Analysis, X ray diffraction, Particle Size, Differential Thermal Analysis, Microsphere, Transmission Electron Microscope, and Coprecipitation
... CY Jones,* SL Marshall, BC Chakoumakos, CJ Rawn, and Y. Ishii . Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun 311-1195, Japan. J. Phys. Chem. ...
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ABSTRACT
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ABSTRACT
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Single crystals of barium samarium titanium oxide Ba6−3xSm8+2xTi18O54 (x = 0.27) have been synthesized and studied using x-ray diffraction. Superstructure reflections, which cause a doubling of the cell along the short axis, were taken... more
Single crystals of barium samarium titanium oxide Ba6−3xSm8+2xTi18O54 (x = 0.27) have been synthesized and studied using x-ray diffraction. Superstructure reflections, which cause a doubling of the cell along the short axis, were taken into account and the refinement was conducted in the orthorhombic space group Pnma. Unit cell parameters from single crystal x-ray diffraction were a = 22.289(1), b = 7.642(1), and c = 12.133(1) Å. Refinement on F resulted in R1 = 5.37% for 1410 Fo > 4σ with the thermal parameters of the Sm and Ba atoms refined anisotropically and the thermal parameters of the Ti and O atoms refined isotropically. The structure is made up of a network of corner sharing TiO6−2 octahedra creating rhombic (perovskite-like) and pentagonal channels. The two pentagonal channels are fully occupied by Ba atoms. The refinement suggests that one rhombic channel is fully occupied by Sm atoms (Sm3/Sm4), one rhombic channel is partially occupied by Sm atoms (100% Sm1/86.25% Sm5...
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Research Interests: Engineering, Physics, Materials Science, Applied Physics, Neutron Diffraction, and 14 moreRietveld refinement, Mathematical Sciences, Applied, Physical sciences, Nitrogen, High Temperature, Thermal Conductivity, Heat Capacity, Room Temperature, Ambient Temperature, Thermal Properties, Thermal Expansion, Linear Coefficient of Thermal Expansion, and Cell Expansion
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... PZT thin films were fabricated by the Inverted Mixing Order (IMO) sol-gel technique, originally reported by Schwartz and co-workers"'". A lead excess of 10 mol% and Zr/Ti molar ratio of 50/50 were used throughout this... more
... PZT thin films were fabricated by the Inverted Mixing Order (IMO) sol-gel technique, originally reported by Schwartz and co-workers"'". A lead excess of 10 mol% and Zr/Ti molar ratio of 50/50 were used throughout this study. ...
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Abstract Sol-gel derived lead zirconate titanate (PZT) thin films were deposited onto monolithic Pt bottom electrodes which used Ti interlayers for Pt adhesion on thermally oxidized〈 111〉 Si. The rf-sputter deposited Pt/Ti films were... more
Abstract Sol-gel derived lead zirconate titanate (PZT) thin films were deposited onto monolithic Pt bottom electrodes which used Ti interlayers for Pt adhesion on thermally oxidized〈 111〉 Si. The rf-sputter deposited Pt/Ti films were annealed at 400°–600° C for 15 minutes. Atomic Force Microscopy (AFM) was used to analyze the Pt surface features. Transmission Electron Microscopy (TEM), transmission electron diffraction, scanning transmission electron microscopy (STEM), and scanning electron microscopy (SEM) were ...
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Page 1. Structure-Property Relations in Mesoscopic BaTi03 and PbTi03 EK AKDOGAN, w. MA YO;^, A. SAFARP, c. J. RAWN~ and E. A. PAYZANTb ... Soc., 79, 2847 (1996). (31 EK Akdogan; WD Porter; CJ Rawn; EA Payzant, CR Hubbard. A. Safari, to... more
Page 1. Structure-Property Relations in Mesoscopic BaTi03 and PbTi03 EK AKDOGAN, w. MA YO;^, A. SAFARP, c. J. RAWN~ and E. A. PAYZANTb ... Soc., 79, 2847 (1996). (31 EK Akdogan; WD Porter; CJ Rawn; EA Payzant, CR Hubbard. A. Safari, to be submitted to Jpn. ...
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Research Interests: Engineering, Earth Sciences, Geology, Computer Science, Carbon Sequestration, and 14 moreGas Hydrate, Complex System, Computers, Fiber Bragg grating, global Climate change, Process Simulation, Distributed Sensing, Energy Production, Natural Environment, Data Distribution, Optical fiber, Data Processing, Indexation, and High Spatial Resolution
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It was previously discovered that the unique structure and chemistry of bacterial cellulose (BC) permits the formation of calcium-deficient hydroxyapatite (CdHAP) nanocrystallites under aqueous conditions at ambient pH and temperature. In... more
It was previously discovered that the unique structure and chemistry of bacterial cellulose (BC) permits the formation of calcium-deficient hydroxyapatite (CdHAP) nanocrystallites under aqueous conditions at ambient pH and temperature. In this study, BC was chemically modified via a limited periodate oxidation reaction to render the composite degradable and thus more suitable for bone regeneration. While native BC does not
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Neutron powder diffraction data confirm that hydrate samples synthesized with propane crystallize as structure type II hydrate. The structure has been modeled using rigid-body constraints to describe C3H8 molecules located in the eight... more
Neutron powder diffraction data confirm that hydrate samples synthesized with propane crystallize as structure type II hydrate. The structure has been modeled using rigid-body constraints to describe C3H8 molecules located in the eight larger polyhedral cavities of a deuterated host lattice. Data were collected at 12, 40, 100, 130, 160, 190, 220, and 250 K and used to calculate the thermal expansivity from the temperature dependence of the lattice parameters. The data collected allowed for full structural refinement of atomic coordinates and the atomic-displacement parameters. PACS No.: 61.12-q
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The polyhedral cage volumes of structure I (sI) (carbon dioxide, methane, trimethylene oxide) and structure II (sII) (methaneethane, propane, tetrahydrofuran, trimethylene oxide) hydrates are computed from atomic positions determined... more
The polyhedral cage volumes of structure I (sI) (carbon dioxide, methane, trimethylene oxide) and structure II (sII) (methaneethane, propane, tetrahydrofuran, trimethylene oxide) hydrates are computed from atomic positions determined from neutron powder-diffraction data. The ideal structural formulas for sI and sII are, respectively, S2L6 · 46H2O and S16L'8 · 136H2O, where S denotes a polyhedral cage with 20 vertices, L a 24-cage, and L' a 28-cage. The space-filling polyhedral cages are defined by the oxygen atoms of the hydrogen-bonded network of water molecules. Collectively, the mean cage volume ratio is 1.91 : 1.43 : 1 for the 28-cage : 24-cage : 20-cage, which correspond to equivalent sphere radii of 4.18, 3.79, and 3.37 Å, respectively. At 100 K, mean polyhedral volumes are 303.8, 227.8, and 158.8 Å3 for the 28-cage, 24-cage, and 20-cage, respectively. In general, the 20-cage volume for a sII is larger than that of a sI, although trimethylene oxide is an exception. Th...
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A single-crystal sapphire cell for performing neutron-scattering experiments on gas hydrates synthesized in situ was designed and fabricated to operate at pressures up to 350 bar (1 bar = 105 Pa) and temperatures between 10 and 300 K. The... more
A single-crystal sapphire cell for performing neutron-scattering experiments on gas hydrates synthesized in situ was designed and fabricated to operate at pressures up to 350 bar (1 bar = 105 Pa) and temperatures between 10 and 300 K. The single-crystal cell is cut off-axis from the c-axis of sapphire to avoid Bragg diffraction in the scattering plane for the DebyeScherrer geometry. The cell is pressurized from a boosted pumping station via a small-diameter stainless-steel pipe. The cell is cylindrical with no external supports. The design of the cell allows the unobstructed detection of neutrons scattered from the sample. This requirement necessitated a departure from the predominant style of sapphire cells reported in the literature. Several iterations of design modifications and finite-element modeling were performed prior to building the prototype. The cell was tested hydrostatically at room temperature. Preliminary inelastic neutron scattering data are reported to verify the p...
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GeTe, a small bandgap semiconductor that has native p-type defects due to Ge vacancies, is an important constituent in the thermoelectric material known as TAGS. TAGS is an acronym for alloys of GeTe with AgSbTe2, and compositions are... more
GeTe, a small bandgap semiconductor that has native p-type defects due to Ge vacancies, is an important constituent in the thermoelectric material known as TAGS. TAGS is an acronym for alloys of GeTe with AgSbTe2, and compositions are normally designated as TAGS-x, where x is the fraction of GeTe. TAGS-85 is the most important with regard to applications, and there
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Page 1. Low-Cycle Fatigue Behavior of ULTIMET® Alloy L. JIANG, CR BROOKS, PK LIAW, J. DUNLAP, CJ RAWN, RA PEASCOE, and DL KLARSTROM The low-cycle fatigue behavior of ULTIMET®, a wrought cobalt-based ...
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Single-crystal X-ray diffraction was used to investigate the structure of the ternary oxide of approximate formula Bi 14 (Sr, Ca) 12 O 33. The crystal examined was found to have a composition Bi 2 Sr 0.68 Ca 1.07 O 4.75 or Bi 16 Sr 5.44... more
Single-crystal X-ray diffraction was used to investigate the structure of the ternary oxide of approximate formula Bi 14 (Sr, Ca) 12 O 33. The crystal examined was found to have a composition Bi 2 Sr 0.68 Ca 1.07 O 4.75 or Bi 16 Sr 5.44 Ca 8.56 O 38 as a result of ...
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Research Interests: Materials Science, Electron Microscopy, Biomaterials, Biomimetics, Hydroxyapatite, and 15 moreFTIR spectroscopy, Scanning Electron Microscopy, Hydrogels, Medicine, Multidisciplinary, Cellulose, Composite Material, X ray diffraction, Bone Substitutes, Elsevier, Calcium Chloride, Durapatite, Fourier transform infrared, Dry Weight, and Bone scan
A single-crystal sapphire cell for performing neutron-scattering experiments on gas hydrates synthesized in situ was designed and fabricated to operate at pressures up to 350 bar (1 bar = 10(5) Pa) and temperatures between 10 and 300 K.... more
A single-crystal sapphire cell for performing neutron-scattering experiments on gas hydrates synthesized in situ was designed and fabricated to operate at pressures up to 350 bar (1 bar = 10(5) Pa) and temperatures between 10 and 300 K. The single-crystal cell is cut off-axis from the c-axis of sapphire to avoid Bragg diffraction in the scattering plane for the Debye-Scherrer
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Research Interests: Engineering, Physics, Materials Science, Applied Physics, Neutron Diffraction, and 14 moreRietveld refinement, Mathematical Sciences, Applied, Physical sciences, Nitrogen, High Temperature, Thermal Conductivity, Heat Capacity, Room Temperature, Ambient Temperature, Thermal Properties, Thermal Expansion, Linear Coefficient of Thermal Expansion, and Cell Expansion
Research Interests: Materials Science, Electron Microscopy, Biomaterials, Biomimetics, Hydroxyapatite, and 15 moreFTIR spectroscopy, Scanning Electron Microscopy, Hydrogels, Medicine, Multidisciplinary, Cellulose, Composite Material, X ray diffraction, Bone Substitutes, Elsevier, Calcium Chloride, Durapatite, Fourier transform infrared, Dry Weight, and Bone scan
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Sol-gel derived lead zirconate titanate (PZT) thin films were deposited onto monolithic Pt bottom electrodes which used Ti interlayers for Pt adhesion on thermally oxidized〈 111〉 Si. The rf-sputter deposited Pt/Ti films were annealed at... more
Sol-gel derived lead zirconate titanate (PZT) thin films were deposited onto monolithic Pt bottom electrodes which used Ti interlayers for Pt adhesion on thermally oxidized〈 111〉 Si. The rf-sputter deposited Pt/Ti films were annealed at 400°–600° C for 15 minutes. Atomic Force Microscopy (AFM) was used to analyze the Pt surface features. Transmission Electron Microscopy (TEM), transmission electron diffraction, scanning transmission electron microscopy (STEM), and scanning electron microscopy (SEM) were ...
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JH Schneibel, CJ Rawn, TR Watkins, and EA Payzant Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831. ... 11 CJ Rawn, JH Schneibel, CM Hoffmann, and CR Hubbard, Intermetallics 9, 209 2001 . ...
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... GA MILLER Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401, USA EA PAYZANT, CJ RAWN Metals and Ceramics Division, Oak Ridge National Laboratory §, Oak Ridge, Tennessee 37831, USA ...
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Single crystals of barium samarium titanium oxide Ba6–3xSm8+ 2xTi18O54 (x 0.27) have been synthesized and studied using x-ray diffraction. Superstructure reflections, which cause a doubling of the cell along the short axis, were taken... more
Single crystals of barium samarium titanium oxide Ba6–3xSm8+ 2xTi18O54 (x 0.27) have been synthesized and studied using x-ray diffraction. Superstructure reflections, which cause a doubling of the cell along the short axis, were taken into account and the refinement was conducted in the orthorhombic space group Pnma. Unit cell parameters from single crystal x-ray diffraction were a 22.2891, b 7.6421, and c 12.1331 A. Refinement on F resulted in R1 5.37% for 1410 Fo. 4s with the thermal parameters of the Sm and Ba atoms ...