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Articles 1 - 22 of 22
Full-Text Articles in Engineering
Nonstoichiometry And Electrical Transport In Sc-Doped Zirconia, Igor Kosacki, Harlan U. Anderson, Yasunobu Mizutani, Kenji Ukai
Nonstoichiometry And Electrical Transport In Sc-Doped Zirconia, Igor Kosacki, Harlan U. Anderson, Yasunobu Mizutani, Kenji Ukai
Materials Science and Engineering Faculty Research & Creative Works
The results of electrical conductivity measurements on ZrO2: Sc (ScSZ) ceramics as a function of oxygen activity and temperature are presented. The influence of the microstructure on electrical transport is discussed and the experimental data for dense microcrystalline specimens have been compared with those obtained for dense nanocrystalline thin films. From these results the electronic and ionic contribution to the electrical transport has been determined and correlated with microstructure. It has been found that nanocrystalline ScSZ films possess quite different nonstoichiometry compared with that observed for microcrystalline specimens in the fact that the electronic conductivity is enhanced so …
Segmented Roll For Casting Metal Strip, James R. Sauer, Ronald J. O'Malley, Robert S. Williams
Segmented Roll For Casting Metal Strip, James R. Sauer, Ronald J. O'Malley, Robert S. Williams
Materials Science and Engineering Faculty Research & Creative Works
Casting molten metal using a segmented roll for casting continuous metal strip. A strip caster (10) for producing a continuous strip (18) includes a tundish for containing a melt and a pair of horizontally disposed water cooled composite casting rolls (84). The casting rolls are juxtaposed relative to one another for forming a pouring basin (16) for receiving molten metal. The composite rolls are formed from a plurality of annular segments (45). Each segment preferably includes at least a pair of coolant openings (34) and means for aligning the coolant openings, such as a pair of alignment openings (26). The …
Microstructure-Electrical Conductivity Relationships In Nanocrystalline Ceria Thin Films, Toshio Suzuki, Igor Kosacki, Harlan U. Anderson
Microstructure-Electrical Conductivity Relationships In Nanocrystalline Ceria Thin Films, Toshio Suzuki, Igor Kosacki, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
A study of nanocrystalline oxide thin film processing and influence of microstructure on the electrical properties of nanocrystalline Gd3+-doped CeO2 thin films was reported. Nanocrystalline films on sapphire substrate were prepared using a polymeric precursor spin coating technique. The grain size of these films depends upon the annealing temperatures and the dopant content, where higher content of dopant realized smaller grain size. The electrical conductivity of nanocrystalline Gd3+-doped CeO2 thin films was studied as a function of temperature and oxygen activity and correlated with the grain size. The results show that the electronic conductivity …
Magnetic Order In Yba₂Cu₃O₆₊ₓ Superconductors, Herbert A. Mook, Pengcheng Dai, Stephen M. Hayden, Arno Hiess, Jeffrey W. Lynn, Seunghun Lee, Fatih Dogan
Magnetic Order In Yba₂Cu₃O₆₊ₓ Superconductors, Herbert A. Mook, Pengcheng Dai, Stephen M. Hayden, Arno Hiess, Jeffrey W. Lynn, Seunghun Lee, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
Polarized and unpolarized neutron diffraction has been used to search for magnetic order in YBa2Cu3O6+x superconductors. Most of the measurements were made on a high quality crystal of YBa2CU3O6.6. It is shown that this crystal has highly ordered ortho-II chain order, and a sharp superconducting transition. Inelastic scattering measurements display a very clean spin-gap and pseudogap with any intensity at 10 meV being 50 times smaller than the resonance intensity. The crystal shows a complicated magnetic order that appears to have three components. A magnetic phase is found at …
Surface Switching Characteristics Of Variable Permittivity Dielectrics, Wayne Huebner, Eric J. Carleton
Surface Switching Characteristics Of Variable Permittivity Dielectrics, Wayne Huebner, Eric J. Carleton
Materials Science and Engineering Faculty Research & Creative Works
Flashover voltage, lifetimes, and switch performance of insulators utilizing square thin and thick film electrodes were examined to determine the viability of using thin electrodes for reliable surface discharge switching. Gold, silver, and platinum were sputtered (0.25 µm) and screen printed (15 µm) onto Al2O3, TiO2, and modified BaTiO3 (MBT), then tested in air at 105 Pa, under vacuum (10-3/ torr), and while immersed in an insulating fluid, SF-2 (manufactured by 3M). For the measured range of 0.5 to 3 mm in air, the flashover voltage for all three insulators …
Observation Of Changes In The Atomic And Electronic Structure Of Single-Crystal Yba₂Cu₃O₆.₆ Accompanying Bromination, Lamine M. Dieng, Yasuhiro Inamura, Trevor A. Tyson, Mark C. Croft, Fatih Dogan, C. Y. Kim, Joseph C. Woicik, James M. Grow
Observation Of Changes In The Atomic And Electronic Structure Of Single-Crystal Yba₂Cu₃O₆.₆ Accompanying Bromination, Lamine M. Dieng, Yasuhiro Inamura, Trevor A. Tyson, Mark C. Croft, Fatih Dogan, C. Y. Kim, Joseph C. Woicik, James M. Grow
Materials Science and Engineering Faculty Research & Creative Works
To ascertain the role of bromination in the recovery of superconductivity in underdoped YBa2Cu3O6+y (YBCO), we have performed polarized multiple-edge x-ray-absorption fine structure (XAFS) measurements on normal (y~0.6) and brominated (Br/Cu~1/30, y~0.6) single crystals with superconducting transitions at 63 and 89 K, respectively. The brominated sample becomes strongly heterogeneous on an atomic length scale. Approximately one-third of YBCO is locally decomposed yet incorporated as a well-ordered "host" lattice as nanoscale regions. The decomposed phase consists of heavily distorted domains with an order not following that of the "host" lattice. Structurally, these domains are fragments of …
Raman Scattering And Lattice Defects In Nanocrystalline Ceo2 Thin Films, Igor Kosacki, Toshio Suzuki, Harlan U. Anderson, Philippe Colomban
Raman Scattering And Lattice Defects In Nanocrystalline Ceo2 Thin Films, Igor Kosacki, Toshio Suzuki, Harlan U. Anderson, Philippe Colomban
Materials Science and Engineering Faculty Research & Creative Works
The results of Raman scattering studies of nanocrystalline CeO2 thin films are presented. The spectra have been described using the spatial correlation model from which the correlation length has been determined as a function of grain size. A direct comparison between the concentration of defects related to correlation length and CeO2 non-stoichiometry has been achieved. The relationship between the lattice disorder and the form of the Raman spectra in nanocrystalline CeO2 is discussed. © 2002 Elsevier Science B.V. All rights reserved.
Room-Temperature Homogeneous Nucleation Synthesis And Thermal Stability Of Nanometer Single Crystal Ceo₂, X.-D. Zhou, Wayne Huebner, Harlan U. Anderson
Room-Temperature Homogeneous Nucleation Synthesis And Thermal Stability Of Nanometer Single Crystal Ceo₂, X.-D. Zhou, Wayne Huebner, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
Nanometer (about 4~5nm) CeO2 single crystals were first synthesized by room-temperature homogeneous nucleation; the size was determined by electron microscopy and specific surfaced area of the particles. Modeling revealed that the surface energy of as-synthesized nanometer single crystals was in the range of 2.8-3.7J/m2. Crystal growth mechanisms change over the temperature regimes, from boundary diffusion over low-temperature regime (Eα=0.16eV) to bulk diffusion (Eα=0.50eV) over high-temperature region.
Evaluation Of Lead Anode Reactions In Acid Sulfate Electrolytes: Ii. Manganese Reactions, Pu Yu, Thomas J. O'Keefe
Evaluation Of Lead Anode Reactions In Acid Sulfate Electrolytes: Ii. Manganese Reactions, Pu Yu, Thomas J. O'Keefe
Materials Science and Engineering Faculty Research & Creative Works
Lead alloys containing calcium-tin, silver, or similar combinations are the primary insoluble anodes used for copper and zinc electrowinning. One potential concern with these anodes is the detrimental effect on cathode purity from incorporation of lead corrosion products. Other factors which are important to process economics are the reaction potential and overpotential required for oxygen evolution. In addition to the inherent overpotential, impurities in the electrolyte can have a significant polarization impact, such as the films that may form when manganese is present. In order to gain a better understanding of the fundamental behavior of various concentrations of manganese ions …
Biodegradable Glass Compositions And Methods For Radiation Therapy, D. E. Day, James E. White
Biodegradable Glass Compositions And Methods For Radiation Therapy, D. E. Day, James E. White
Materials Science and Engineering Faculty Research & Creative Works
A nonradioactive glass in particulate form adapted for radiation therapy in a mammal comprise a biodegradable rare earth-lithium borate glass material of a specified composition which, upon being subjected to an effective amount of neutron irradiation, will produce a beta or gamma emitting radioisotope, the radioisotope being distributed throughout the glass material, the glass upon being introduced into a body fluid for radiation therapy being adapted to react therewith causing the radioisotope to form an insoluble compound on the surface of the glass material which is retained in the glass material and thereby prevented from escaping from the treatment site. …
Synthesis Of Pmma-Ceramics Nanocomposites By Spray Process, X.-D. Zhou, H. C. Gu
Synthesis Of Pmma-Ceramics Nanocomposites By Spray Process, X.-D. Zhou, H. C. Gu
Materials Science and Engineering Faculty Research & Creative Works
PMMA-ceramics nanocomposites particles were synthesized by a spray process. PMMA-ZnO compositions showed a higher homogeneous than PMMA-SiO2. The surface of PMMA-SiO2 composites was SiO2 rich. Donut shape particles were formed at high gas flow rate, which was due to the competition between surface tension and dragging force. The Zeta potential dramatically changed in PMMA-ZnO composites whereas there was a slight change in PMMA-SiO2 system.
Method For Preparing Porous Shells Or Gels From Glass Particles, D. E. Day, Samuel D. Conzone
Method For Preparing Porous Shells Or Gels From Glass Particles, D. E. Day, Samuel D. Conzone
Materials Science and Engineering Faculty Research & Creative Works
A method is provided for preparing shells, concentric shells or porous, homogenous gels from alkali borate glass particles at low temperatures (i.e. room temperature or less than above 100° C.). The alkali borate glass particles contain one or more cations such as aluminum which react with an aqueous solution containing an anion such as hydroxide to form an aqueous insoluble material having a solubility limit of less than about 0.01 wt. percent. TTie resulting shells or gels may be used in many different applications such as a filler in resins, as filters, precursors for nano-sized powders, as thin surface films …
Charge And Spin Structure In Yba₂Cu₃O₆.₃₅, Herbert A. Mook, Pengcheng Dai, Fatih Dogan
Charge And Spin Structure In Yba₂Cu₃O₆.₃₅, Herbert A. Mook, Pengcheng Dai, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
Neutron scattering has been used to measure the charge and spin structure in the highly underdoped superconductor YBa2Cu3O6.35. Incommensurate static charge ordering is found that remains at high temperatures. The magnetic pattern is complex with a resonance and incommensurate structure observed at low temperatures. The results clarify the role of striped phases in YBa2Cu3O6 + x superconductors.
Optical Properties Of Undoped And Gd-Doped Ceo2 Nanocrystalline Thin Films, Toshio Suzuki, Igor Kosacki, Vladimir Petrovsky, Harlan U. Anderson
Optical Properties Of Undoped And Gd-Doped Ceo2 Nanocrystalline Thin Films, Toshio Suzuki, Igor Kosacki, Vladimir Petrovsky, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
The results of studies of the preparation, structure, and optical properties of undoped and Gd-doped CeO2 thin films are presented. Dense films with 4-150 nm grain size have been obtained on monocrystalline sapphire substrates using a polymeric precursor spin coating method. The results of the optical measurements are presented and correlated with the microstructure of the films. The transmission spectra have been used to determine the energy dependence of the refractive index, n and the extinction coefficient, k. Both n and k of the thin films decreased as grain size decreased and these results showed that this change could …
Corrosion Resistant Nickel-Based Alloy, Joseph William Newkirk, Sanhong Zhang
Corrosion Resistant Nickel-Based Alloy, Joseph William Newkirk, Sanhong Zhang
Materials Science and Engineering Faculty Research & Creative Works
A nickel based, high silicon alloy exhibits very high corrosion resistance in high temperature sulfuric acid environments. The alloy may be cast and is sufficiently ductile to be fabricated and machined. The alloy is ductile and has sufficient resistance to mechanical and thermal shock to be reliable in service when used as rotating parts.
Agglomerated Lubricant, Mary R. Reidmeyer
Agglomerated Lubricant, Mary R. Reidmeyer
Materials Science and Engineering Faculty Research & Creative Works
A lubricant for use in lubricating the shot sleeve of a machine for die casting molten metals is in the form of agglomerated particles. The particles have an inorganic high pressure lubricant agglomerated, with a binder material and with an organic material. The solid lubricant is resistant to dusting, caking and breakage, can be fed through an automatic dispensing machine, and combines inorganic and organic materials to achieve excellent lubrication properties. The product has low flash and low smoke release into the environment.
Neodymium And Erbium Coordination Environments In Phosphate Glasses, Mevlüt Karabulut, G. K. Marasinghe, Ezzeldin Metwalli, Andrew K. Wittenauer, Richard K. Brow, C. H. Booth, D. K. Shuh
Neodymium And Erbium Coordination Environments In Phosphate Glasses, Mevlüt Karabulut, G. K. Marasinghe, Ezzeldin Metwalli, Andrew K. Wittenauer, Richard K. Brow, C. H. Booth, D. K. Shuh
Materials Science and Engineering Faculty Research & Creative Works
The local structures of Nd3+ and Er3+ ions in two series of rare-earth (RE) phosphate glasses with nominal compositions xR203-(1-x)P2O5, where R=Nd and Er and 0.05≤x≤0.28, have been characterized by LIII-edge extended x-ray-absorption fine-structure spectroscopy (EXAFS). The RE coordination number depends on the R2O3 content, decreasing from 9.0 (10) oxygen nearest neighbors in ultraphosphate compositions (x<0.15) to 6.4 (9) oxygen nearest neighbors for the metaphosphate (x∼0.25) compositions. The average Er-O bond distance decreases from 2.29 (1) to 2.23 (1) Å, and the average Nd-O bond distance decreases from 2.40 (1) to 2.37 (1) Å over the same compositional range. The changes in coordination environments are consistent with the conversion of isolated RE polyhedra to clustered RE polyhedra sharing common oxygens as the number of available terminal oxygens per RE ion decreases with increasing x.
Raman Spectroscopy Of Nanocrystalline Ceria And Zirconia Thin Films, Igor Kosacki, Vladimir Petrovsky, Harlan U. Anderson, Philippe Colomban
Raman Spectroscopy Of Nanocrystalline Ceria And Zirconia Thin Films, Igor Kosacki, Vladimir Petrovsky, Harlan U. Anderson, Philippe Colomban
Materials Science and Engineering Faculty Research & Creative Works
The results of Raman-scattering studies of nanocrystalline CeO2 and ZrO2:16% Y (YSZ) thin films are presented. The relationship between the lattice disorder and the form of the Raman spectra is discussed and correlated with the microstructure. It is shown that the Raman line shape results from phonon confinement and spatial correlation effects and yields information about the material nonstoichiometric level.
Misinformation [1], Hollis P. Leighly
Misinformation [1], Hollis P. Leighly
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Defect And Mixed Conductivity In Nanocrystalline Doped Cerium Oxide, Toshio Suzuki, Igor Kosacki, Harlan U. Anderson
Defect And Mixed Conductivity In Nanocrystalline Doped Cerium Oxide, Toshio Suzuki, Igor Kosacki, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
The results obtained from a study on the microstructure and the electrical properties of Gd-doped CeO2 thin films were reported. Dense, nanocrystalline films on sapphire substrates are prepared using a polymeric precursor spin coating technique. The electrical conductivity was studied as a function of temperature and oxygen activity and correlated with the grain size. For nanocrystalline Gd-doped CeO2 thin films, the ionic conductivity increased with decreasing activation energy as the grain size decreased. A conductivity model was developed to analyze PO2 behavior of the electrical conductivity. Using the conductivity model, the hopping energy of electron conduction and …
Evaluating And Monitoring Nucleation And Growth In Copper Foil, Ye Kun Lee, Thomas J. O'Keefe
Evaluating And Monitoring Nucleation And Growth In Copper Foil, Ye Kun Lee, Thomas J. O'Keefe
Materials Science and Engineering Faculty Research & Creative Works
The electrodeposition of copper foil for use in electronic materials applications is a complex and demanding process. The specific aspects of producing and controlling the structure-property-performance requirements of the foil are important because of the stringent demands placed on their use in printed circuit boards and similar products. In this paper, a brief review of the electrodeposition process for raw copper foil is presented. Since electrolyte additives play such a significant role in the copper-deposition process, the effects of two essential additives, chloride ion and an organic (e.g., glue or gelatine), on the foil are described. Also, the influence of …
Reactive Hot Pressing Of Alumina-Molybdenum Disilicide Composites, William Fahrenholtz, Ronald E. Loehman, Kevin G. Ewsuk
Reactive Hot Pressing Of Alumina-Molybdenum Disilicide Composites, William Fahrenholtz, Ronald E. Loehman, Kevin G. Ewsuk
Materials Science and Engineering Faculty Research & Creative Works
Al2O3-MoSi2 Composites Were Prepared by Reactive Hot Pressing using Molybdenum, Aluminum, and Mullite Powders as Precursors. the Gibbs Free Energy Was Highly Negative for the Composite-Forming Reaction, Which Indicated that the Products Were Stable Relative to the Reactants. after the Reaction, the Composites Had High Relative Density, ∼96%. based on the Composite-Forming Reaction, the Composites Should Have Contained 18 Vol% MoSi2 in an Al2O3 Matrix. Scanning Electron Microscopy Revealed that the MoSi2 Inclusions Were Elongated, with an Average Thickness of ∼5 Μm and Inclusion Lengths that Ranged from 5 to 50 …