Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Alloys (1)
- Attrition Milled Powders (1)
- Average Grain Sizes (1)
- Brine leaching (1)
- Carbon/carbon composites (1)
-
- Ceramics (1)
- Chromium (1)
- Compaction (1)
- Detoxification (1)
- Dielectric Hysteresis (1)
- Dielectric Losses (1)
- Dielectric Properties (1)
- EAF dust (1)
- Elastic modulus (1)
- Electro-discharge (1)
- Electrostriction (1)
- Electrostrictive Properties (1)
- Electrowinning (1)
- Environment (1)
- Fatigue (1)
- Fatigue failure, fatigue run out, striations (1)
- Ferroelectric Materials (1)
- Grain Size (1)
- Grain Size Effect (1)
- High temperature (1)
- High-Electric-Field Applications (1)
- Induced Piezoelectric Properties (1)
- Lanthanum oxide (1)
- Lead Compounds (1)
- Magnesium Compounds (1)
Articles 1 - 25 of 25
Full-Text Articles in Engineering
Electrochemical Evaluation Of The Adherence Of Zinc To Aluminum Cathodes, Jang Sop Han, Thomas J. O'Keefe
Electrochemical Evaluation Of The Adherence Of Zinc To Aluminum Cathodes, Jang Sop Han, Thomas J. O'Keefe
Materials Science and Engineering Faculty Research & Creative Works
Excess fluoride ions in zinc electrolyte are known to cause problems with the removal of electrowon zinc from aluminum blanks. The mechanisms responsible for this undesirable adherence were studied. Acid zinc sulfate electrolyte similar to that employed in zinc electrowinning was used. Using electrolyte containing various fluoride ion concentrations, the initial nucleation and growth morphology of zinc and the aluminum electrode surface were examined using scanning electron microscopy. Electrochemical tests were also carried out in various solutions to obtain a better understanding of the polarization behavior of the system. © 1992.
Structural Ceramic Incorporating Boron Carbide Whiskers For The Strengthening Thereof, P. D. Ownby, J. Liu
Structural Ceramic Incorporating Boron Carbide Whiskers For The Strengthening Thereof, P. D. Ownby, J. Liu
Materials Science and Engineering Faculty Research & Creative Works
Ceramic composites, and in particular structural ceramic composites, have enhanced strength, toughness and abrasion resistance due to the presence of up to about 40 volume percent of relatively large boron carbide whiskers. Although whiskers of various sizes were studied, those of particular interest are whiskers having an average diameter greater than about 3 micrometers, and particularly about 5 to about 8 micrometers, with an average aspect ratio of about 50. Due to the larger size, which had been predicted to be detrimental, there is less respiratory health risk when using these whiskers in the manufacturing of thse improved ceramic composites. …
Investigation Of Strontium-Doped La(Cr, Mn)O3 For Solid Oxide Fuel Cells, Rasit Koc, Harlan U. Anderson
Investigation Of Strontium-Doped La(Cr, Mn)O3 For Solid Oxide Fuel Cells, Rasit Koc, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
The (La, Sr) (Cr, Mn)O3 system was investigated in an effort to develop an interconnect and cathode materials for solid oxide fuel cells. Sintering studies were done in air at temperatures below 1500°C. Significant improvements in densification were observed with substitution of 50 mol% Mn for chromium and a density of 95% theoretical was achieved with the substitution of 70 mol% Mn for chromium in the La(Cr, Mn)O3 system. Electrical conductivity (d.c.) measurements were made as a function of temperature and oxygen activity. At 1000°C and 1 atm oxygen, the electrical conductivity ranged from 2.2-20 S cm-1 …
Morphology, Deformation, And Defect Structures Of Ticr2 In Ti-Cr Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Morphology, Deformation, And Defect Structures Of Ticr2 In Ti-Cr Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Materials Engineering
The morphologies and defect structures of TiCr2 in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr2. The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking faul4 and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability.
The Effect Of Additives On The Nucleation And Growth Of Copper Onto Stainless Steel Cathodes, M. Sun, Thomas J. O'Keefe
The Effect Of Additives On The Nucleation And Growth Of Copper Onto Stainless Steel Cathodes, M. Sun, Thomas J. O'Keefe
Materials Science and Engineering Faculty Research & Creative Works
A potentiostatic technique has been used to study the effects of chloride ion, glue, and thiourea on the initial electrodeposition of copper. A stainless steel (AISI 304) rotating disc electrode (RDE) with an electrolyte containing 40 g/1 Cu2+ and 180 g/1 H2SO4 at 40 °C was employed. The current transients from the potential step measurements for the additive-free electrolyte could be fitted to a model that assumed progressive nucleation followed by growth of three-dimensional (3-D) centers under diffusion control. The growth mechanism and the type of nuclei were also confirmed by scanning electron microscopy (SEM) of …
Use Of High-Energy Radiation For Degradation Of Environmental Pollutants, Robert D. Guthrie, Manjiri Patwardhan
Use Of High-Energy Radiation For Degradation Of Environmental Pollutants, Robert D. Guthrie, Manjiri Patwardhan
KWRRI Research Reports
The purpose of this project was to explore the advantages and/or limitations of high-energy radiation treatment as a method for degrading organic pollutants, particularly aryl halides, in an aqueous medium. We have done analyses of 60Co-irradiated samples and kinetic studies using pulsed electron beams. For aryl halides containing no more than two fused rings, the main products detected are those of simple halogen replacement by hydrogen, although the amount of aryl halide destroyed was always greater than the total amount of products detected. To accomplish halogen replacement by H, the reaction solvent may not be pure water but must …
On The Creep Deformation Of A Cast Near Gamma Tial Alloy Ti-48al-1nb, R. W. Hayes, B. London
On The Creep Deformation Of A Cast Near Gamma Tial Alloy Ti-48al-1nb, R. W. Hayes, B. London
Materials Engineering
The steady-state creep deformation behavior of a cast two phase gamma TiAl alloy having the composition Ti---48Al---1Nb (at.%) has been studied. Tension creep tests using the stress increment technique (θθ2θ3) were conducted over the temperature range of 704–850°C at constant initial applied stress level of 103.4–241.3 MPa. The activation energy for creep over the temperature and stress regime of this study varied 317.5 kJ/mol (137.8 MPa) up to 341.0 kJ/mol (206.8 MPa) with an average value of 326.4 kJ/mol. This is well within the range of values previously measured for gamma TiAl alloys where creep controlled by volume diffusion has …
The Degradation Of Aluminium Cathodes By Fluoride Ion During Zinc Electrowinning, J. S. Han, Thomas J. O'Keefe
The Degradation Of Aluminium Cathodes By Fluoride Ion During Zinc Electrowinning, J. S. Han, Thomas J. O'Keefe
Materials Science and Engineering Faculty Research & Creative Works
The influence of fluoride ions on aluminum cathode surface degradation during zinc electrowinning has been studied. Electrolyte with a composition similar to that employed in plant operations has been used. A direct correlation is shown between the electrolyte fluoride content and the number of deposition cycles possible before zinc removal becomes difficult. The role of initial nucleation and starting electrode morphology is discussed in terms of the degree of adherence observed. Electrochemical tests have also been made on the electrodes at various stages of the process in an attempt to gain a better fundamental understanding of the mechanisms responsible for …
Stimulation Of Amorphizing Reactions In Co-Si Multi-Layers, Jeanne K. Jackson
Stimulation Of Amorphizing Reactions In Co-Si Multi-Layers, Jeanne K. Jackson
Opportunities for Undergraduate Research Experience Program (OURE)
Co-Si multi-layer specimens do not normally amorphize. To possibly stimulate amorphization, Ti was added by evaporation and the specimens were annealed at 300 and 400 degrees Celsius. The results showed that amorphization occurred at 400 degrees Celsius in the presence of Ti, but did not occur at 300 degrees Celsius. Further research would be necessary to conclude whether the amorphization was stimulated by the addition of Ti or the temperature increase.
Cyclodextrin Stationary Phases For The Gas-Solid Chromatographic Separation Of Hydrocarbons, Chris A. Monge
Cyclodextrin Stationary Phases For The Gas-Solid Chromatographic Separation Of Hydrocarbons, Chris A. Monge
Opportunities for Undergraduate Research Experience Program (OURE)
Cyclodextrin, bonded to silica gel and used as a gas-solid chromatographic stationary phase provides a practical and efficient means for separating a wide variety of C1-C7 hydrocarbons at ambient to elevated temperatures. Conditioning the columns at high temperature (300°C) for several hours increased efficiency and resolution. The adsorption of these light hydrocarbons involves a multiple retention mechanism. Evaluation of the columns and an analogous silica gel column with hydrocarbon standards is reported. Capacity factors and chromatograms are presented for these GSC stationary phases.
Steady-State Creep Deformation Of Investment Cast Near-Gamma Titanium Aluminide, D. A. Wheeler, B. London, D. E. Larsen Jr.
Steady-State Creep Deformation Of Investment Cast Near-Gamma Titanium Aluminide, D. A. Wheeler, B. London, D. E. Larsen Jr.
Materials Engineering
No Abstract.
High Temperature Alloys Synthesis By Electro-Discharge Compaction, Kenji Okazaki
High Temperature Alloys Synthesis By Electro-Discharge Compaction, Kenji Okazaki
Chemical and Materials Engineering Faculty Patents
A method is provided for synthesizing high temperature alloys from elemental powders. The method includes the steps of placing the elemental powders to be processed in a die. A relatively high pressure is then applied to the powders. Substantially simultaneously, an electrical discharge is applied to the powders. The discharge is of relatively high voltage and current density to provide alloying. A product fabricated by the present method is also described and claimed.
Grain Size Effect On The Induced Piezoelectric Properties Of 0.9pmn-0.1pt Ceramic, U. Kumar, Wayne Huebner, P. Marsh, H. Kankul, S. F. Wang, Clyde G. Oakley
Grain Size Effect On The Induced Piezoelectric Properties Of 0.9pmn-0.1pt Ceramic, U. Kumar, Wayne Huebner, P. Marsh, H. Kankul, S. F. Wang, Clyde G. Oakley
Materials Science and Engineering Faculty Research & Creative Works
Lead magnesium niobate-lead titanate (Pb(Mg1/3Nb2/3)O3 - PbTiO3 (PT) solid solutions have been widely researched to produce devices that can be used in low- and high-electric-field applications. For some applications, such as medical ultrasonic transducers, it is necessary to prepare the ceramic with high density and small average grain size. The effect of grain size on the low- and high-field properties of 0.9-PMN-0.10-PT ceramics is described in the present work. To prepare highly dense ceramic, vibratory and attrition milled powders were sintered between 1000 and 1250 ⁰C. The average grain sizes of the sintered ceramics …
Application Of Optical Emission Diagnostics And Control Related To Semiconductor Processing, Richard N. Savage, Greg C. Viloria
Application Of Optical Emission Diagnostics And Control Related To Semiconductor Processing, Richard N. Savage, Greg C. Viloria
Materials Engineering
This paper discusses and shows applications of optical emission spectroscopy techniques and methods to monitor plasma emissions during semiconductor processing. A brief discussion of the instrumentation that was used and the software to control the instrumentation is presented. Optical emission spectroscopy techniques discussed include chemical species identification in plasma etching, process fingerprinting, contamination detection, endpoint analysis/control, and sputter/deposition plasma monitoring.
Sme Annual Meeting. Phoenix, Usa. February 22-27, 1992, Johh L. Watson
Sme Annual Meeting. Phoenix, Usa. February 22-27, 1992, Johh L. Watson
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Mixed‐Cation Oxide Powders Via Resin Intermediates Derived From A Water‐Soluble Polymer, Lone‐Wen ‐W Tai, Harlan U. Anderson, Paul A. Lessing
Mixed‐Cation Oxide Powders Via Resin Intermediates Derived From A Water‐Soluble Polymer, Lone‐Wen ‐W Tai, Harlan U. Anderson, Paul A. Lessing
Materials Science and Engineering Faculty Research & Creative Works
Sub micrometer powders of complex oxides were prepared via resin intermediates based on a starch type of organic precursor. A commercially available water‐soluble starch derivative was (for the first time) used as the organic base for solution synthesis of ceramic powders. Calcination of the charred, fluffy, amorphous resins at a temperature below 600°C for 4 h yielded perovskite powders of Sr‐doped LaMnO3 and Sr‐doped La(Fe,Co)O3. Sr‐doped LaCrO3 needed to be calcined above 750°C to ensure phase purity and to remove organic residue. Due to the low cost of starch derivatives, the process has the potential of …
Solvent Extraction Reagent Entrainment Effects On Zinc Electrowinning From Waste Oxide Leach Solutions, M. Neira, Thomas J. O'Keefe, Johh L. Watson
Solvent Extraction Reagent Entrainment Effects On Zinc Electrowinning From Waste Oxide Leach Solutions, M. Neira, Thomas J. O'Keefe, Johh L. Watson
Materials Science and Engineering Faculty Research & Creative Works
A considerable quantity of metal-containing waste oxide is generated by the primary metal industry, and under increased environmental regulation, treatment of these wastes has become viable. Hydrometallurgical processing is often appropriate and one potential treatment process for zinc oxide wastes involves leaching the oxide with an acid, purifying by a solvent extraction operation, and recovering metallic zinc by electrowinning the purified leach solution. The purification stage is frequently critical and the introduction of a solvent extraction organic reagent into the flowsheet can be detrimental to downstream processes. The object of this study was to determine the effect of organics, entrained …
Effect Of Ultrasound On Acidified Brine Leaching Of Double-Kiln Treated Eaf Dust, J. A. Barrera-Godinez, Thomas J. O'Keefe, Johh L. Watson
Effect Of Ultrasound On Acidified Brine Leaching Of Double-Kiln Treated Eaf Dust, J. A. Barrera-Godinez, Thomas J. O'Keefe, Johh L. Watson
Materials Science and Engineering Faculty Research & Creative Works
The U.S. steel industry produces approximately 500,000 tons/year of electric arc furnace (EAF) dust, which is classified as a hazardous waste. Increasing disposal costs of these dusts have encouraged studies to investigate treatment processes to render the material non-hazardous, and to possibly recover metal values. This research project was designed to examine the hydrometallurgical recovery of zinc from EAF dusts that have been treated by a double kiln fuming process. The test work consisted essentially of acidified brine leaching of the pelletized calcine to determine the influence of traditional conditions, such as acid concentration, temperature and agitation, plus the application …
Review Of P-Type Doped Perovskite Materials For Sofc And Other Applications, Harlan U. Anderson
Review Of P-Type Doped Perovskite Materials For Sofc And Other Applications, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
p-type perovskite-type oxides are candidates for use as components of high temperature fuel cells and as oxygen separation membranes. The particular properties that these applications require are reviewed. The characteristics that these oxides have which allow them to satisfy many of these requirements are discussed and a defect model presented. The status of the utilization of these oxides and of the areas which need to be addressed such as thermal expansion and sintering characteristics are reviewed. © 1992.
Electrical Conductivity And Seebeck Coefficient Of (La, Ca) (Cr, Co)O3, R. Koc, Harlan U. Anderson
Electrical Conductivity And Seebeck Coefficient Of (La, Ca) (Cr, Co)O3, R. Koc, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
Electrical conductivity and Seebeck coefficients of (La, Ca) (Cr, Co)O3 were measured as a function of temperature. The electrical conductivity as measured in air from 100 to 1100 °C increased with increasing Co and Ca content. The Seebeck coefficients were positive, indicating p-type conductivity. The substitution of Co for Cr significantly decreased the Seebeck coefficients, indicating that the substitution resulted in an increase in site occupancy, associated with the Co. The additional Ca substitution for La resulted in further decrease in the Seebeck coefficients, then exhibited a temperature-independent behaviour, indicating that the carrier mobility, rather than carrier concentration, was …
Effect Of Cation Substitution On The Thermal Expansion Coefficient Of Lacro3, R. Koc, Harlan U. Anderson
Effect Of Cation Substitution On The Thermal Expansion Coefficient Of Lacro3, R. Koc, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Method Of Making Highly Sinterable Lanthanum Chromite Powder, Von Richards, Subhash C. Singhal
Method Of Making Highly Sinterable Lanthanum Chromite Powder, Von Richards, Subhash C. Singhal
Materials Science and Engineering Faculty Research & Creative Works
A highly sinterable powder consisting essentially of LaCrO.sub.3, containing from 5 weight % to 20 weight % of a chromite of dopant Ca, Sr, Co, Ba, or Mg and a coating of a chromate of dopant Ca, Sr, Co, Ba, or Mg; is made by (1) forming a solution of La, Cr, and dopant; (2) heating their solutions; (3) forming a combined solution having a desired ratio of La, Cr, and dopant and heating to reduce solvent; (4) forming a foamed mass under vacuum; (5) burning off organic components and forming a charred material; (6) grinding the charred material; (7) …
Tensile Fatigue Behaviour Of Tightly Woven Carbon/Carbon Composites, A. Ozturk, Robert E. Moore
Tensile Fatigue Behaviour Of Tightly Woven Carbon/Carbon Composites, A. Ozturk, Robert E. Moore
Materials Science and Engineering Faculty Research & Creative Works
The tensile fatigue behavior of a tightly woven carbon/carbon composite was investigated as a function of stress level. Load-controlled fatigue tests were performed in tension-tension mode with a stress ratio, R, of 0.1 under ambient laboratory conditions. Results of composite behavior are discussed in terms of the relationship of the stress/strain behavior to the fatigue life of these composites as well as the effects of applied stress levels. It is shown that these composites exhibit good resistance to cyclic loading. No fatigue failures were obtained after 106 cycles when the maximum tensile load in the fatigue cycle is less than …
X‐Ray Powder Diffraction Structural Phase‐Transition Study Of La(Cr1‐Xmnx)O3 (X = 0 To 0.25) Using The Rietveld Method Of Analysis, Scott A. Howard, Jen‐Kuan ‐K Yau, Harlan U. Anderson
X‐Ray Powder Diffraction Structural Phase‐Transition Study Of La(Cr1‐Xmnx)O3 (X = 0 To 0.25) Using The Rietveld Method Of Analysis, Scott A. Howard, Jen‐Kuan ‐K Yau, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
The La(Cr1‐xMnx)O3 (x = 0 to 0.25) system exhibited a displacive phase transformation from an orthorhombic to a rhombohedral structure at temperatures ranging from about 256°C at x= 0 to 305°C at x= 0.25. The Rietveld method of X‐ray analysis was used to determine structural characteristics and to assay phase concentrations when multiple phases were present. Indications were that the Mn ions on the B site affected the transition temperature through an ionic size effect; i.e., Mn3+, with a larger ionic size than Cr3+, increased the transition temperature while the presence …
An Experimental Method For Determining Membrane Penetration, Jong W. Choi, Isao Ishibashi
An Experimental Method For Determining Membrane Penetration, Jong W. Choi, Isao Ishibashi
Civil & Environmental Engineering Faculty Publications
A new and simple experimental method is proposed for the determination of membrane penetration due to changes of the effective confining pressure in triaxial and hollow cylinder tests. The proposed method has advantages over existing methods in that it requires neither special devices nor questionable assumptions. It only requires a series of drained isotropic compression tests in a conventional triaxial device with plastic liners. The results from the proposed method are compared to those from several existing experimental and analytical methods.