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Materials Science and Engineering Faculty Research & Creative Works

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Articles 781 - 810 of 1006

Full-Text Articles in Materials Science and Engineering

Incommensurate One-Dimensional Fluctuations In Yba2cu3o6.93, Herbert A. Mook, Pengcheng Dai, K. Salama, D. Lee, Fatih Dogan, G. Aeppli, A. T. Boothroyd, M. E. Mostoller Jul 1996

Incommensurate One-Dimensional Fluctuations In Yba2cu3o6.93, Herbert A. Mook, Pengcheng Dai, K. Salama, D. Lee, Fatih Dogan, G. Aeppli, A. T. Boothroyd, M. E. Mostoller

Materials Science and Engineering Faculty Research & Creative Works

A novel neutron scattering technique has been utilized to discover one-dimensional fluctuations with a very sharply defined modulation period of 16.65 Å along the ba direction in YBa2Cu3O6.93. The fluctuations are found to be absent in the reduced oxygen compound YBa2Cu3O6.15. The wave vector of the fluctuations is consistent with accepted values of 2kF for the Cu-O chains.

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Method Of Coating A Substrate With A Metal Oxide Film From An Aqueous Solution Comprising A Metal Cation And A Polymerizable Organic Solvent, Harlan U. Anderson, Magdi M. Nasrallah, Chieh-Cheng Chen Feb 1996

Method Of Coating A Substrate With A Metal Oxide Film From An Aqueous Solution Comprising A Metal Cation And A Polymerizable Organic Solvent, Harlan U. Anderson, Magdi M. Nasrallah, Chieh-Cheng Chen

Materials Science and Engineering Faculty Research & Creative Works

A method for preparing a substrate coated with a polycrystalline, metal oxide film using polymeric precursors. The oxide films prepared by the method of the present invention are dense (i.e., substantially free of cracks and pinholes) and may be used, for example, as an electrolyte or electrode in intermediate temperature solid oxide fuel cells (SOFCs) or as gas separation membranes.

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High-Frequency Spin Waves In Yba₂Cu₃O6.15>/Sub>, Stephen M. Hayden, Gabriel Aeppli, Toby G. Perring, Herbert A. Mook, Fatih Dogan Jan 1996

High-Frequency Spin Waves In Yba₂Cu₃O6.15>/Sub>, Stephen M. Hayden, Gabriel Aeppli, Toby G. Perring, Herbert A. Mook, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Pulsed neutron spectroscopy is used to absolute measurements of the dynamic magnetic susceptibility of insulating YBa2Cu3O6.15. Acoustic and optical modes, derived from inand out-of-phase oscillation of spins in adjacent CuO2 planes, dominate the spectra and are observed up to 250 meV. The optical modes appear first at 74±5 meV. Linear-spin-wave theory gives an excellent description of the data and yields intralayer and interlayer exchange constants of J∥=125±5 meV and J⊥=11±2 meV, respectively, and a spin-wave intensity renormalization ZΧ=0.4±0.1.

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Structure And Phase Transformation Of Lanthanum Chromate, J. D. Carter, Harlan U. Anderson, M. G. Shumsky Jan 1996

Structure And Phase Transformation Of Lanthanum Chromate, J. D. Carter, Harlan U. Anderson, M. G. Shumsky

Materials Science and Engineering Faculty Research & Creative Works

Lanthanum chromate (LaCrO4) was synthesized as a low temperature ( < 700°C) intermediate to perovskite-type, lanthanum chromite (LaCrO3). The lattice parameters, atom positions and bond lengths determined from X-ray powder diffraction show that LaCrO4 forms a monazite-type crystal structure. Lanthanum chromate forms a solid solution with Ca, having a solubility between 10 and 20 at %. Thermal analysis shows that at ambient oxygen pressure, LaCrO4 transforms to LaCrO3 at a temperature near 700°C. It also indicates that (La,Ca)CrO4 initially transforms to LaCrO3 and CaCrO4 with the subsequent formation of a (La,Ca)CrO3 solid solution. Evidence of Ca segregation to the surface of (La,Ca) CrO3 particles is given by Auger electron spectroscopy and scanning electron microscopy. © 1996 Chapman & Hall.

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Liquid Phase Behaviour In Nonstoichiometric Calcium-Doped Lanthanum Chromites, J. D. Carter, M. M. Nasrallah, Harlan U. Anderson Jan 1996

Liquid Phase Behaviour In Nonstoichiometric Calcium-Doped Lanthanum Chromites, J. D. Carter, M. M. Nasrallah, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The sinter ability of (La,Ca)CrO3 is analyzed by comparing the liquid phase behavior in A-site excess and A-site deficient compositions (referring to the ABO3 formula). The analysis shows that a series of A-site excess and deficient compositions form distinct liquid phases belonging to the CaO-Cr2O3 phase system. Although both series experience grain growth and densification due to the presence of a liquid phase, the A-site excess compositions exhibit greater shrinkage and sinter to closed porosity, whereas the A-site deficient compositions remain porous. During the final stages of sintering, surplus liquid from the A-site excess material exudes to the free-surface forming …

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Effect Of Pt Doping On Nucleation And Crystallization In Li2o · 2sio2 Glass: Experimental Measurements And Computer Modeling, K. Lakshmi Narayan, K. F. Kelton, C. S. Ray Jan 1996

Effect Of Pt Doping On Nucleation And Crystallization In Li2o · 2sio2 Glass: Experimental Measurements And Computer Modeling, K. Lakshmi Narayan, K. F. Kelton, C. S. Ray

Materials Science and Engineering Faculty Research & Creative Works

Heterogeneous nucleation and its effects on the crystallization of lithium disilicate glass containing small amounts of Pt are investigated. Measurements of the nucleation frequencies and induction times with and without Pt are shown to be consistent with predictions based on the classical nucleation theory. A realistic computer model for the transformation is presented. Computed differential thermal analysis data (such as crystallization rates as a function of time and temperature) are shown to be in good agreement with experimental results. This modeling provides a new, more quantitative method for analyzing calorimetric data.

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Q Dependence Of Self-Energy Effects Of The Plane Oxygen Vibration In Yba2cu3o7, D. Reznik, Bernard Keimer, Fatih Dogan, Ilhan A. Aksay Sep 1995

Q Dependence Of Self-Energy Effects Of The Plane Oxygen Vibration In Yba2cu3o7, D. Reznik, Bernard Keimer, Fatih Dogan, Ilhan A. Aksay

Materials Science and Engineering Faculty Research & Creative Works

We have measured the temperature dependence of the peak position and linewidth of the 42.5 meV phonon branch in a twinned single crystal of YBa2Cu3O7 as a function of wave vector q. In the (100)/(010) direction in the Brillouin zone, considerable softening and broadening occur below the superconducting transition temperature Tc at some values of q. We observe an order of magnitude smaller softening and no linewidth broadening for q in the (110) / (1⁢1⁢0-) direction. Possible implications of these findings for the symmetry of the superconducting order parameter are …

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Phonon And Magnetic Neutron Scattering At 41 Mev In Yba2cu3o7, Hung Fai Fong, Bernard Keimer, Pw Anderson, D. Reznik, Fatih Dogan, Ilhan A. Aksay Jul 1995

Phonon And Magnetic Neutron Scattering At 41 Mev In Yba2cu3o7, Hung Fai Fong, Bernard Keimer, Pw Anderson, D. Reznik, Fatih Dogan, Ilhan A. Aksay

Materials Science and Engineering Faculty Research & Creative Works

We report inelastic neutron scattering measurements at excitation energies ħ⁢w∼41 meV in YBa2Cu3O7. We separate magnetic and phonon contributions to the scattering cross section by a detailed analysis of the momentum dependence of the scattered intensity. The previously reported broad peak around q = (π/a,π/a) in the normal state can be entirely accounted for by a phonon which primarily involves vibrations of the in-plane oxygen. Magnetic scattering centered around 41 meV and q = (π/a,π/a) appears in the superconducting state only. Theoretical implications of …

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Radiolabeled Protein Composition And Method For Radiation Synovectomy, D. E. Day, Gary J. Ehrhardt, Kurt R. Zinn Apr 1995

Radiolabeled Protein Composition And Method For Radiation Synovectomy, D. E. Day, Gary J. Ehrhardt, Kurt R. Zinn

Materials Science and Engineering Faculty Research & Creative Works

A radiolabeled protein composition adapted for radiation therapy which comprises a radioisotope and a protein material containing about 6 or more percent amino acids which have a sulfhydryl-containing side chain. A method for carrying out radiation synovectomy of arthritic joints. Rhenium radiolabeled protein micro- spheres are administered which contain cysteine and other amino acids. A method for radiolabeling a protein composition whereby the composition is treated with a reducing agent capable of reducing disulfides to sulfhydryls prior to radiolabeling.

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Electrical Characterization Of The (La,Ca) (Cr,Co)O3 System, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin Jan 1995

Electrical Characterization Of The (La,Ca) (Cr,Co)O3 System, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin

Materials Science and Engineering Faculty Research & Creative Works

The results of electrical conductivity and thermopower measurements are presented for selected (La,Ca)(Cr,Co)O3 compositions. The La1 - xCaxCrO3 compounds are typical p-type small polaron conductors. The La1 - xCaxCrO3 compounds are found to be small polaron conductors at room temperature for x ≤ 0.20 with a higher electrical conductivity than the corresponding chromite's. The electrical conductivity at room temperature is lower for Co-rich compositions than for Cr-rich compositions for compositions containing 10 mol% and 20 mol% Ca. This fact is attributed to the trapping of p-type small polarons at energetically lower Cr sites, resulting in a broad room temperature conductivity …

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Structure And Electrical Properties Of La1 - Xsrxco1 - Yfeyo3. Part 2. The System La1 - Xsrxco0.2fe0.8o3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin Jan 1995

Structure And Electrical Properties Of La1 - Xsrxco1 - Yfeyo3. Part 2. The System La1 - Xsrxco0.2fe0.8o3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin

Materials Science and Engineering Faculty Research & Creative Works

Crystal structure, thermal expansion, oxygen stoichiometry, thermoelectricity, and electrical conductivity of compositions in the system La1 - xSrxCo0.2Fe0.8O3 with 0 ≤ x ≤ 0.6 were studied as function of temperature and Sr content, in air. The solubility of Sr in the sintered perovskite-type oxide (ABO3) was limited to x ≤ 0.4. The observed p-type electrical conduction appeared to occur via a small-polaron hopping mechanism. The thermally induced oxygen loss caused a lattice expansion plus decreases in both the carrier concentration and the carrier mobility. A semi-empirical model was developed which takes into account the thermally activated disproportionation of Co3+ ions …

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Method Of Forming A Plasma Sprayed Interconnection Layer On An Electrode Of An Electrochemical Cell, Charles J. Spengler, George R. Folser, Shailesh D. Vora, Lewis Kuo, Von Richards Jan 1995

Method Of Forming A Plasma Sprayed Interconnection Layer On An Electrode Of An Electrochemical Cell, Charles J. Spengler, George R. Folser, Shailesh D. Vora, Lewis Kuo, Von Richards

Materials Science and Engineering Faculty Research & Creative Works

A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO.sub.3 powder, preferably compensated with chromium as Cr.sub.2 O.sub.3 and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO.sub.3 layer to about 1100 to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive …

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A Positron Annihilation Study Of Rotating Beam Fatigue Damage In The Superalloy Haynes 188, D. Hoeckelman, Hollis P. Leighly Jan 1995

A Positron Annihilation Study Of Rotating Beam Fatigue Damage In The Superalloy Haynes 188, D. Hoeckelman, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Immittance Response Of La0.6sr0.4co0.2fe0.8o3 Based Electrochemical Cells, C. C. Chen, M. M. Nasrallah, Harlan U. Anderson Jan 1995

Immittance Response Of La0.6sr0.4co0.2fe0.8o3 Based Electrochemical Cells, C. C. Chen, M. M. Nasrallah, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The ac small-signal response of La0.6Sr0.4CO02Feo.803 (LSCF) is examined via lumped parameter/complex plane analysis (LP/CPA) technique. The ac data, acquired in the frequency range lO-1≤F≤106Hz, are used to establish the role of ionic contribution in the LSCF material system using a two-terminal blocking electrode method. Spun-on yttria (8 mole percent (m/o) Y203) stabilized zirconia (8YSZ) or Ce0.85Sm0.15O2 (CSO) thin film coatings (0.3 - 1.0 µm) is used as electron blocking electrodes. The temperature dependence of the contributing elements between the terminals, obtained via LP/CPA technique and dc measurements, is evaluated. The activation energy, associated with possible oxygen transport via an …

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Electrical And Thermal Transport Properties Of (La,Ca)(Cr,Co)O3, Rasit Koc, Harlan U. Anderson Jan 1995

Electrical And Thermal Transport Properties Of (La,Ca)(Cr,Co)O3, Rasit Koc, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

DC electrical conductivity and Seebeck data as functions of temperature and oxygen activity were used to explain the electrical and thermal transport properties of (La,Ca) (Cr,Co)O3. The electrical conductivity data of La (Cr,Co)O3 suggested that it depends upon Co content. At Co concentrations less than 20 mol%, Co acted as traps for the carriers and decreased the electrical conductivity of the compositions at temperatures less than 900 °C. As the Co concentration increased to above 20 mol%, electrical conductivity increased significantly due to a connecting path of available Co sites. Additional Ca substitution for La increased the electrical conductivity in …

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Structure And Electrical Properties Of La1-Xsrxco1-Yfeyo3. Part 1. The System La0.8sr0.2co1-Yfeyo3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin Jan 1995

Structure And Electrical Properties Of La1-Xsrxco1-Yfeyo3. Part 1. The System La0.8sr0.2co1-Yfeyo3, L. W. Tai, M. M. Nasrallah, Harlan U. Anderson, Don M. Sparlin, S. R. Sehlin

Materials Science and Engineering Faculty Research & Creative Works

Crystal structure, thermal expansion, thermogravimetry, thermoelectricity, and electrical conductivity of compositions in the system La0.8Sr0.2Co1-yFeyO3 with 0 ≤ y ≤ 1 were studied as function of Co Fe ratio and temperature, in air. The electrical conduction mechanism is attributed to the adiabatic-hopping of p-type small polarons. At high temperatures, oxygen deficiency causes lattice expansion and a reduction in electrical conductivity. The observed temperature dependence of the Seebeck coefficient is attributed to changes in carrier concentration caused by a thermally excited charge disproportionation of Co3+ ions and by the ionic compensation of induced oxygen vacancies. The measured electrical conductivity and Seebeck …

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Semiempirical Model For The Electrical Properties Of La1-Xcaxcoo3, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin Jan 1995

Semiempirical Model For The Electrical Properties Of La1-Xcaxcoo3, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin

Materials Science and Engineering Faculty Research & Creative Works

A semiempirical model of the Seebeck coefficient for a small polaron hopping conductor is presented. The population of small polarons is allowed to change as a function of temperature via the mechanism of charge disproportionation. The energy required for polaron formation by the disproportionation mechanism is modeled as screened by a Coulomb interaction with nearby small polarons. The charge carrier site occupancies generated by the model are used to successfully predict the electrical conductivity and Seebeck coefficient for compositions in the La1-xCaxCoO3 system. Cobalt ion valence populations predicted by the model are used to calculate effective paramagnetic moments for LaCoO3, …

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High Temperature Interfacial Phenomena In Processing Cofired Ceramics For Electronic Packaging Of Semiconductor Devices, P. D. Ownby, D. A. Weirauch Jr., J. E. Lazaroff Jan 1995

High Temperature Interfacial Phenomena In Processing Cofired Ceramics For Electronic Packaging Of Semiconductor Devices, P. D. Ownby, D. A. Weirauch Jr., J. E. Lazaroff

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Anomalous-Diffusion Model Of Ionic Transport In Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow Jan 1995

Anomalous-Diffusion Model Of Ionic Transport In Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

The power-law frequency dependence of both the conductivity, (), and permittivity, (), of ion-conducting materials suggests that self-similar or scale-invariant behavior influences the transport of ions at high frequencies. Using an anomalous-diffusion model, we derive relevant power-law expressions for () and () and compare these with measurements performed on LiPO3 glass. Superior fits to the measured data are obtained compared to the commonly used Kohlrausch-Williams-Watts (KWW) description of the electrical modulus, most particularly in the notorious high-frequency regime. Evaluation of our results in terms of an anomalous-diffusion model suggests the dominance of interaction-based constraints to diffusion. © 1995 The American …

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Two Contributions To The Ac Conductivity Of Alkali Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow Jan 1995

Two Contributions To The Ac Conductivity Of Alkali Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

Although the frequency dependent conductivity of ion-containing glasses often displays scale invariant power law dispersion at high temperatures, the exponent increases to unity at lower temperatures. We report measurements of the conductivity of a series of alkali metaphosphate glasses including a mixed alkali composition and demonstrate that this temperature dependence results from the superposition of two power law dispersions originating from separate mechanism, and does not indicate any intrinsic change in scaling of the process which dominates at high temperatures. © 1995 The American Physical Society.

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Vortex Lattice Symmetry And Electronic Structure In Yba2cu3o7, Bernhard Keimer, Wan Y. Shih, Ross W. Erwin, Jeffrey W. Lynn, Fatih Dogan, Ilhan A. Aksay Dec 1994

Vortex Lattice Symmetry And Electronic Structure In Yba2cu3o7, Bernhard Keimer, Wan Y. Shih, Ross W. Erwin, Jeffrey W. Lynn, Fatih Dogan, Ilhan A. Aksay

Materials Science and Engineering Faculty Research & Creative Works

We report a small angle neutron scattering study of the vortex lattice in YBa2Cu3O7 in magnetic fields of 0.5≤ H ≤5 T applied along and close to the c axis. Over the entire field range, the vortices form an oblique lattice with two nearly equal lattice constants and an angle of 73° between primitive vectors. Numerical calculations suggest that variations of the superconducting order parameter near the vortex core are important in stabilizing this structure. An analysis that accounts for the fourfold symmetry of the vortex core qualitatively explains both the symmetry and the orientation …

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Method Of Manufacture Of Multiple-Element Piezoelectric Transducer, Lawrence J. Busse, Jeffry W. Stevenson, Wayne Huebner Nov 1994

Method Of Manufacture Of Multiple-Element Piezoelectric Transducer, Lawrence J. Busse, Jeffry W. Stevenson, Wayne Huebner

Materials Science and Engineering Faculty Research & Creative Works

An improved method for fabrication of a multiple-element piezoelectric transducer and the transducer produced thereby. A green precursor tape is produced by doctor-blade tape-casting of a slurry containing lead zirconate-titanate (PZT) powder. After drying, individual strips of the tape are stacked between flat plates of previously sintered PZT, and sintered to form PZT strips; Pb from the previously sintered PZT plates makes up any Pb lost from the surfaces of the tape strips during sintering. The PZT strips are stacked interposed by layers of a thermoplastic polymer, and heated to a temperature above the melting point of the polymer, forming …

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Nature Of The Ferroelectric Phase Transition In Pbtio3, Noam Sicron, B. Ravel, Y. Yacoby, Edward A. Stern, Fatih Dogan, John J. Rehr Nov 1994

Nature Of The Ferroelectric Phase Transition In Pbtio3, Noam Sicron, B. Ravel, Y. Yacoby, Edward A. Stern, Fatih Dogan, John J. Rehr

Materials Science and Engineering Faculty Research & Creative Works

We have measured quantitatively the temperature dependence of the local distortions of PbTiO3 crystals below and above the structural ferroelectric phase transition, using x-ray absorption fine-structure (XAFS) measurements. Two probe atoms, Pb and Ti, were used. The results were analyzed by fitting parametrized theoretical XAFS spectra to the experimental results. These measurements provide quantitative ‘‘distortion parameters’’ defined as the difference between the distance of the probe to its nearest neighbor measured in the actual structure and that in a centrosymmetric structure with the same unit cell dimensions. At low temperatures the Pb-edge spectra were fit using four shells and included …

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Effect Of Additives On Anomalous Deposition In Zinc-Cobalt Alloy Electrogalvanizing, H. M. Wang, Thomas J. O'Keefe Sep 1994

Effect Of Additives On Anomalous Deposition In Zinc-Cobalt Alloy Electrogalvanizing, H. M. Wang, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

Alloys of Zn-Co were deposited from sulphate electrolytes containing various additives to study their influence on the anomalous behavior of the reactions. The effects of antimony, germanium and arsenic on the Zn-Co alloy composition and structure were examined. The results showed that the composition and structure of Zn-Co alloys deposited could be dramatically changed by antimony, and to a lesser extent by germanium and arsenic. A concentration of Sb(III) as low as 5 mg dm-3 increased the cobalt content by a factor of approximately 3; however, the deposit morphology was very dendritic. Germanium additions nearly doubled the cobalt content and …

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Simple Apparatus For Producing Single Liquid Drops, Dhiren Panda, D. G. C. Robertson Jul 1994

Simple Apparatus For Producing Single Liquid Drops, Dhiren Panda, D. G. C. Robertson

Materials Science and Engineering Faculty Research & Creative Works

A simple experimental apparatus has been used to produce individual mercury and sodium amalgam drops in the size range of 0.3-2.5 mm diam. A high resistance to the flow of liquid was provided by a capillary tube. The cross section consisted of a 0.20 mm o.d. tungsten wire placed in a 0.25 mm capillary bore. By this method, flow rates of 1 μl/s and lower were obtained, which enabled the formation of drops as small as 1 mm diam in a time interval of 20 s. The drops were formed at a plastic tip, and on reaching the desired size, …

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The Response Of Dispersion-Strengthened Copper Alloys To High Fluence Neutron Irradiation At 415⁰C, Danny J. Edwards, Joseph William Newkirk, Frank A. Garner, Margaret L. Hamilton, A. Nadkarni, P. Samal Jun 1994

The Response Of Dispersion-Strengthened Copper Alloys To High Fluence Neutron Irradiation At 415⁰C, Danny J. Edwards, Joseph William Newkirk, Frank A. Garner, Margaret L. Hamilton, A. Nadkarni, P. Samal

Materials Science and Engineering Faculty Research & Creative Works

Various oxide-dispersion-strengthened copper alloys have been irradiated to 150 dpa at 415°C in the Fast Flux Test Facility (FFTF). The Al2O3-strengthened GlidCop™ alloys, followed closely by a HfO2-strengthened alloy, displayed the best swelling resistance, electrical conductivity, and tensile properties. The conductivity of the HfO2-strengthened alloy reached a plateau at the higher levels of irradiation, instead of exhibiting the steady decrease in conductivity observed in the other alloys. A high initial oxygen content resulted in significantly higher swelling for a series of castable oxide-dispersion-strengthened alloys, while a Cr2O3 -strengthened alloys …

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Microspheres For Radiation Therapy, D. E. Day, Gary J. Ehrhardt Apr 1994

Microspheres For Radiation Therapy, D. E. Day, Gary J. Ehrhardt

Materials Science and Engineering Faculty Research & Creative Works

Microspheres for radiation therapy of a mammal which have a non-radioactive isotope which emits beta or gamma radiation of therapeutic intensity upon being irradiated. The microspheres also contain elements which do not become radioactive upon irradiation. The chemical durability of the microspheres is such that they do not release a significant amount of radiation emitting radioisotope into the mammal’s system upon administration. Microspheres containing phosphorus or yttrium; and carbon, nitrogen, fluorine, sodium, magnesium, aluminum, silicon, potassium, vanadium, manganese, gallium, niobium, iodine and/or lead.

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Fabrication Of 2-2 Connectivity Pzt/Thermoplastic Composites For High Frequency Linear Arrays, Wayne Huebner, Mary R. Reidmeyer, L. Busse, Jeffry W. Stevenson Jan 1994

Fabrication Of 2-2 Connectivity Pzt/Thermoplastic Composites For High Frequency Linear Arrays, Wayne Huebner, Mary R. Reidmeyer, L. Busse, Jeffry W. Stevenson

Materials Science and Engineering Faculty Research & Creative Works

An alternate approach for fabricating PZT/polymer composites with 2-2 connectivity with fine scales is described. Thin (less than or equal to 20 micrometers) sintered PZT plates and sheets of a thermoplastic polymer film (less than or equal to 10 micrometers) were bonded together via thermal processing. Stack sintering of tape cast PZT generated the necessary PZT plates, while tape cast polymers were used to control the thermoplastic thickness. Composite blocks were cut to required dimensions for linear arrays, electroded, and poled. Electromechanical properties were measured to evaluate the composites. The significance of this fabrication technique is that it is able …

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Density Changes During Isothermal Annealing Of A Quenched Pb–7.45 At% Sn Alloy, Hollis P. Leighly, A. Belaidi Jan 1994

Density Changes During Isothermal Annealing Of A Quenched Pb–7.45 At% Sn Alloy, Hollis P. Leighly, A. Belaidi

Materials Science and Engineering Faculty Research & Creative Works

The increase in density of a Pb–7.45 at% Sn alloy annealed at 150, 165, 180, and 195 °C and quenched at 20, 21.5, 23, 25, and 30 °C is measured isothermally. This increase in density accompanies the formation of the Sn‐rich phase precipitating as a function of time at the quenching temperature. The quenching is rapid enough to retain some vacancies at equilibrium at the annealing temperature. These vacancies accelerate the early stages of precipitation. The change in density versus time obeys the kinetic law allowing the determination of the reaction rate constant for several annealing and quenching conditions. Copyright …

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Characterization Of Phase Transformation Behavior In Electrolytically Produced Indium-Thallium Shape Memory Alloy Films, Chong Ho Sonu, Thomas J. O'Keefe Jan 1994

Characterization Of Phase Transformation Behavior In Electrolytically Produced Indium-Thallium Shape Memory Alloy Films, Chong Ho Sonu, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

Indium-thallium alloys in the range 15-38 at. % Tl were electrodeposited from a sulfate electrolyte by using pulsed current. The relationship between composition and phase structure of the alloys deposited was investigated with regard to the shape memory effect. To date there have been no reported experimental studies describing the electrodeposition of InTl alloys capable of undergoing such transformations. Not only did the deposited alloys exhibit the shape memory effect, but the composition-phase relationship exhibited was shown to deviate from that reported for alloys in an equilibrium condition. The results show that the temperature and the temperature interval for the …

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