Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
- Publication
Articles 1 - 20 of 20
Full-Text Articles in Engineering
Room Temperature Wear Characteristics Of Al2O3-Particle-Reinforced Aluminum Alloy Composite, A. R. Nesarikar, Surendra N. Tewari, E. E. Graham
Room Temperature Wear Characteristics Of Al2O3-Particle-Reinforced Aluminum Alloy Composite, A. R. Nesarikar, Surendra N. Tewari, E. E. Graham
Chemical & Biomedical Engineering Faculty Publications
Room temperature dry wear and friction properties of a metal matrix composite sliding against cast iron have been studied in a pin-on-plate reciprocating wear tester. The composite consists of Al2O3 particles in an aluminum alloy matrix. Wear is caused by abrasion, interfacial adhesion and ploughing of the softer surface with the asperities of the harder surface and the debris. With increasing load the friction coefficient and wear initially increase and then ecrease. The decreases in wear and friction are caused by increased hardness resulting from re-embedding of the fractured Al2O3 particles near the surface …
Sol-Gel Derived, Air-Baked Indium And Tin Oxide Films, Douglas M. Mattox
Sol-Gel Derived, Air-Baked Indium And Tin Oxide Films, Douglas M. Mattox
Materials Science and Engineering Faculty Research & Creative Works
A sol-gel derived, transparent, electrically conducting tin-doped In2O3 film system has been developed which only requires air baking. The films approximate the properties of sputtered and hot-sprayed films but are simpler and less expensive to apply by dipping and spinning procedures. Substrate sodium interference was seen to be minimal. © 1991.
Analysis Of Transport Phenomena In The Coating Of Fibers By Cvd, J H. Scholtz, J E. Gatica, Hendrik J. Viljoen
Analysis Of Transport Phenomena In The Coating Of Fibers By Cvd, J H. Scholtz, J E. Gatica, Hendrik J. Viljoen
Papers in Materials Science
Inorganic coated fibres produced by chemical vapour deposition find several technological applications. In this CVD process, a filler core is mounted in a reactor between two electrodes. Reactive gases flow over the substrate and react near or on the fibre surface to form the desired coating. Experience has showed that, quality deposition can only be obtained over a small range of the governing parameters: these parameters are, however, difficult to control. In the present, study a mathematical model is developed for the reactor configuration under consideration. The different mass and energy transport mechanisms are compared and their influence on the …
Composition And Method For Radiation Synovectomy Of Arthritic Joints, D. E. Day, Gary J. Ehrhardt
Composition And Method For Radiation Synovectomy Of Arthritic Joints, D. E. Day, Gary J. Ehrhardt
Materials Science and Engineering Faculty Research & Creative Works
A method for preparing nonradioactive microspheres adapted for radiation synovectomy of arthritic joints in a mammal involves forming the microspheres by doping a biodegradable glass material which may be lithium or potassium silicate, lithium or potassium aluminosilicate, lithium or potassium aluminoborate, lithium or potassium germanate or lithium or potassium alumino- germanate with an isotope which may be samarium, holmium, erbium, dysprosium, rhemium or yttrium so that the isotope is chemcially dissolved in and distributed uniformly throughout the glass material. The doped glass material is then treated with an acid wash to produce a thin layer on the surface thereof and …
Solutal Partition Coefficients In Nickel-Based Superalloy Pwa-1480, Surendra N. Tewari, M. Vijayakumar, James E. Lee, P. A. Curreri
Solutal Partition Coefficients In Nickel-Based Superalloy Pwa-1480, Surendra N. Tewari, M. Vijayakumar, James E. Lee, P. A. Curreri
Chemical & Biomedical Engineering Faculty Publications
Solutal profiles in dendritic single-crystal specimens of PWA-1480 nickel-base superalloy, which were directionally solidified and quenched, were examined on several transverse cross-sections to obtain the partition coefficients. Similar to their nickel-base binaries, the partition coefficients of tantalum, titanium, and aluminum were found to be less than unity; those of tungsten and cobalt were greater than unity. The partition coefficients were temperature independent in the range 1584-1608 K. The contribution of solid-state diffusion to microsegregation was observed to be negligible.
Apparatus And Method For Automatically Identifying Chemical Species Within A Plasma Reactor Environment, Richard N. Savage
Apparatus And Method For Automatically Identifying Chemical Species Within A Plasma Reactor Environment, Richard N. Savage
Materials Engineering
A method and apparatus to control the plasma environment in a semiconductor or thin-film fabrication chamber. The apparatus and method include a means for measuring an optical emission spectrum of the chemical species in the plasma and a library containing a multiplicity of predefined spectral patterns. A processor automatically correlates the spectrum with the predefined spectral patterns in the library, and yields a correlation value for all the correlations. A subset of the predefined spectral patterns based upon the highest correlation values are selected and used to identify the chemical species and abundances thereof in the plasma. A comparator compares …
Radioactive Glass Microspheres, D. E. Day, Gary J. Ehrhardt
Radioactive Glass Microspheres, D. E. Day, Gary J. Ehrhardt
Materials Science and Engineering Faculty Research & Creative Works
A radioactive microsphere for radiation therapy of a mammal comprising a biologically compatible glass material containing a beta or gamma emitting radioisotope distributed substantially uniformly throughout the glass. Advantageously, the radioisotope is produced by irradiation of the microsphere.
Composition And Method For Radiation Synovectomy Of Arthritic Joints, D. E. Day, Gary J. Ehrhardt
Composition And Method For Radiation Synovectomy Of Arthritic Joints, D. E. Day, Gary J. Ehrhardt
Materials Science and Engineering Faculty Research & Creative Works
Radioactive microspheres for radiation synovectomy of arthritic joints in a mammal comprises a biodegradable glass material and a beta radiation emitting radioisotope chemically dissolved in and distributed substantially uniformly throughout the glass material. The biodegradable glass material may be lithium silicate, lithium aluminosilicate, lithium aluminoborate, lithium germa- nate, lithium aluminogermanate, potassium silicate, potassium aluminosilicate, potassium aluminoborate, potassium germanate or potassium aluminogermanate and the beta radiation emitting radioisotope may be samarium-153, holmium-166, erbium-169, dysprosium-165, rhenium-186, rhenium-188 or yttrium-90. Method for preparing such microspheres and for carrying out radiation synovectomy of arthritic joints utilizing such microspheres are also disclosed.
Removal Of Chlorine From Chlorine-Nitrogen Mixture In A Film Of Liquid Water, Sarwan S. Sandhu
Removal Of Chlorine From Chlorine-Nitrogen Mixture In A Film Of Liquid Water, Sarwan S. Sandhu
Chemical and Materials Engineering Faculty Publications
In industry there are many examples of absorption of a gas with or without chemical reaction in the liquid phase. In physical absorption, a particular gaseous component is removed from a gas mixture due to its larger solubility in the liquid phase solvent. The removal of butane and pentane from a refinery gas mixture by a heavy oil in the liquid phase is an example of physical absorption. In absorption with chemical reaction, the gaseous component to be removed transfers across the gas-liquid interface due to a difference in the bulk chemical potentials or concentrations in the two phases. The …
Measuring Hydrogen In Galvanized Steels, Timothy O'Hearn
Measuring Hydrogen In Galvanized Steels, Timothy O'Hearn
Opportunities for Undergraduate Research Experience Program (OURE)
There has been much investigation in the past concerning ways to eliminate the embrittling effects of hydrogen in galvanized steel components. Such galvanized parts are used extensively in the automotive industry. One solution that is commonly used is to anneal the galvanized parts at approximately 200 degrees Celsius for 4 to 24 hours. This annealing process does restore the ductility. However, very few if any experiments have been done to measure the amount of hydrogen released and the temperature dependence of the hydrogen release. This investigation is part of an on going effort to measure the hydrogen released from galvanized …
The Electrochemical Characterization Of Ferrocene As A Guest Molecule In The Presence Of Ss-Cydodextrin, Anne T. Roberson
The Electrochemical Characterization Of Ferrocene As A Guest Molecule In The Presence Of Ss-Cydodextrin, Anne T. Roberson
Opportunities for Undergraduate Research Experience Program (OURE)
This experiment involves the development of electrochemical experimental methods for the determination of the oxidation/reduction potentials of a guest ferrocene complex (C10H10Fe) hosted by ß-cyclodextrin. The project was conducted so that the specific interaction of two molecules forming a unique inclusion compound can be used as a model for rapid analysis of other small molecules. In principle, the study is based on the expected equilibrium interaction of the iron compound with ß-cyclodextrin resulting in a complexed and an uncomplexed species equilibrium. The project's experimental objective is to determine if the redox potentials of both complexed and …
Phase Separation In Glasses, N. J. Kreidl
Phase Separation In Glasses, N. J. Kreidl
Materials Science and Engineering Faculty Research & Creative Works
The detection, acceptance and further investigation of glass-glass phase separation was closely connected with the development of methods making detection possible, such as electron microscope technique pioneered and exploited by Werner Vogel, to whom this paper is dedicated on the occasion of his 65th birthday. Structures are not always found in agreement with rules derived from thermodynamic principles, and also depend on thermal history, as well as mode of preparation. The phenomenon is exemplified in many glass-forming systems. Among more recent applications are the control of crystallization by preceding phase separation as in glass-ceramics and semiconductor-doped glasses for non-linear optics. …
Dendrite Spacings In Directionally Solidified Superalloy Pwa-1480, M. Vijayakumar, Surendra N. Tewari, James E. Lee, P. A. Curreri
Dendrite Spacings In Directionally Solidified Superalloy Pwa-1480, M. Vijayakumar, Surendra N. Tewari, James E. Lee, P. A. Curreri
Chemical & Biomedical Engineering Faculty Publications
Primary dendrite spacings and side-branch coarsening kinetics were examined in specimens of the single-crystal multicomponent commercial superalloy PWA-1480, which were directionally solidified in a positive thermal gradient. The experimentally observed dependence of primary dendrite spacings and side-branch coarsening kinetics on growth rate and thermal gradient were in agreement with the behavior predicted by analytical models developed for binary alloys.
In-Situ Film Thickness Measurements For Real-Time Monitoring And Control Of Advanced Photoresist Track Coating Systems, Richard N. Savage, Thomas E. Metz, Horace O. Simmons
In-Situ Film Thickness Measurements For Real-Time Monitoring And Control Of Advanced Photoresist Track Coating Systems, Richard N. Savage, Thomas E. Metz, Horace O. Simmons
Materials Engineering
This paper explores the methodologies of real-time measurement of photoresist film thickness on silicon wafers using multi-wavelength reflection interferometry. Reflected light from the wafer's surface, containing the interference profile, is collected in-situ via a fiber optic cable and film thickness is determined in real-time via a pattern recognition algorithm. The instrumentation used to make this measurement and its application toward optimizing track performance during spin-coating and back are discussed. Data demonstrating basic thickness versus spin-time and thickness versus bake-time profiles acquired on-line without process disruption are presented along with its utilization toward minimizing process set-up and machine qualification. Moreover, the …
Effects Of Sample Orientation On The Corrosion Of Zinc In Ammonium Sulfate And Sodium Hydroxide Solutions, D. Abayarathna, Edward Boyd Hale, Thomas J. O'Keefe, Y. M. Wang, D. Radovic
Effects Of Sample Orientation On The Corrosion Of Zinc In Ammonium Sulfate And Sodium Hydroxide Solutions, D. Abayarathna, Edward Boyd Hale, Thomas J. O'Keefe, Y. M. Wang, D. Radovic
Physics Faculty Research & Creative Works
The corrosion and electrochemical properties of three zinc single crystal surfaces with different orientations have been investigated. In near-neutral 1 M (NH4)2SO4, the corrosion rates on all three surfaces were found to be similar. However, the SEM morphologies of the corresponding corroded surfaces were markedly different from each other, but consistent with preferential attack of {1120} surfaces. In alkaline 0.5 N NaOH solution, the three sample orientations showed significantly different reactivities, with the (1120) surface exhibiting the highest reactivity and corrosion rate. Here, passivation ultimately occurred and the difference in the corrosion performance of …
Electrical Conductivity, Seebeck Coefficient And Defect Chemistry Of Ca-Doped Ycro3, G. F. Carini, Harlan U. Anderson, Don M. Sparlin, M. M. Nasrallah
Electrical Conductivity, Seebeck Coefficient And Defect Chemistry Of Ca-Doped Ycro3, G. F. Carini, Harlan U. Anderson, Don M. Sparlin, M. M. Nasrallah
Materials Science and Engineering Faculty Research & Creative Works
The electrical transport behavior and defect structure of Ca-doped YCrO3 were studied using electrical conductivity and Seebeck coefficient measurements as a function of oxygen activity and temperature. Defect models derived from the electrical conductivity data were found to adequately relate the concentration of charge carriers to the acceptor dopant and oxygen vacancy concentrations. Thermodynamic properties were calculated and found to be consistent with the model. Activation energy and carrier mobility data were also obtained. The analysis of the electrical conductivity, Seebeck and mobility data suggest that the conduction process in Ca-doped YCrO3 occurs via the small polaron hopping …
Synthesis And Characterization Of Barium Lanthanum Titanates, Jyoti P. Guha
Synthesis And Characterization Of Barium Lanthanum Titanates, Jyoti P. Guha
Materials Science and Engineering Faculty Research & Creative Works
Ternary compounds in the system BaO—TiO2—La2O3 were prepared by the solid‐state reaction technique at temperatures between 1300° and 1400°C using precursor oxides as the starting materials. In an alternative processing technique, BaTiO3 was reacted with appropriate proportions of prefabricated lanthanum titanates at 1350°C to obtain the compounds. Two compounds were identified in the TiO2‐rich region of the system. The X‐ray powder diffraction pattern of a compound with a chemical composition BaLa2Ti3O10 (BaO·La2O3·3TiO2) is indexed on the basis of an orthorhombic unit …
Positron Study Of Defects And Diffusion Induced Grain Boundary Migration In A Pb-Sn System, A. Belaidi, Hollis P. Leighly, H. Aourag, B. Khelifa, M. Oubadi, A. Elias
Positron Study Of Defects And Diffusion Induced Grain Boundary Migration In A Pb-Sn System, A. Belaidi, Hollis P. Leighly, H. Aourag, B. Khelifa, M. Oubadi, A. Elias
Materials Science and Engineering Faculty Research & Creative Works
The Pb-Sn system discloses a remarkable effect at the intermediate α → α + β phase boundary. The observation of the sharp transient peak in the S-parameter curve which is analogous to those found in thermal capacity curves is, as far as the authors are aware, unique in such positron measurements. This effect is interpreted in terms of positron trapping in defects associated with the strains accompanying the initial stage of transformation. This short note offers a new approach to the underlying phenomenon published in J. Phys. F. Met. Phys., 12 (1982) 813 by A. Belaidi, H. P. Leighly Jr. …
Defect Structure, Nonstoichiometry, And Phase Stability Of Ca-Doped Ycro3, G. F. Carini, Harlan U. Anderson, M. M. Nasrallah, Don M. Sparlin
Defect Structure, Nonstoichiometry, And Phase Stability Of Ca-Doped Ycro3, G. F. Carini, Harlan U. Anderson, M. M. Nasrallah, Don M. Sparlin
Materials Science and Engineering Faculty Research & Creative Works
The dependence of the defect structure of Ca-doped YCrO3 on oxygen activity and temperature was investigated by high temperature thermogravimetric measurements. Defect models developed from electrical conductivity data obtained in a previous study were used to interpret the thermogravimetric data. A correlation was found between the electrical conductivity and the thermogravimetric data which suggested that these data were concomitantly dependent on the acceptor dopant and oxygen vacancy dependance of the thermodynamic parameters. Kröger-Vink type diagrams showing the regions of stability with respect to oxygen activity and temperature were constructed. The TGA data show that Ca-doped YCrO3 is even …
Compensation Modes In Counterdoped Rutile, M. M. Nasrallah, Harlan U. Anderson
Compensation Modes In Counterdoped Rutile, M. M. Nasrallah, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
Thermogravimetric measurements were conducted on undoped, Nb5+ or Ta5+ donor-doped, and Al3+ acceptor doped rutile at 1000°C and 105-10-7 Pa oxygen activity. Nb5+ or Ta5+ doped rutile was counter doped by Al3+ in order to identify the role of Al3+ acceptor and its effect on donor doped rutile. Our results show that both dopants enter the lattice substitutionally for Ti4+, that Al3+ is as effective an acceptor as Nb5+ or that Ta5+ is effective as a donor, and the compensation occurs on a one-to-one basis. Earlier reports indicate …