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Missouri University of Science and Technology

Materials Science and Engineering Faculty Research & Creative Works

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1991

Articles 1 - 10 of 10

Full-Text Articles in Engineering

Sol-Gel Derived, Air-Baked Indium And Tin Oxide Films, Douglas M. Mattox Sep 1991

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.


Composition And Method For Radiation Synovectomy Of Arthritic Joints, D. E. Day, Gary J. Ehrhardt Aug 1991

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 …


Composition And Method For Radiation Synovectomy Of Arthritic Joints, D. E. Day, Gary J. Ehrhardt Apr 1991

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.


Radioactive Glass Microspheres, D. E. Day, Gary J. Ehrhardt Apr 1991

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.


Phase Separation In Glasses, N. J. Kreidl Mar 1991

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. …


Synthesis And Characterization Of Barium Lanthanum Titanates, Jyoti P. Guha Jan 1991

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 …


Compensation Modes In Counterdoped Rutile, M. M. Nasrallah, Harlan U. Anderson Jan 1991

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 …


Electrical Conductivity, Seebeck Coefficient And Defect Chemistry Of Ca-Doped Ycro3, G. F. Carini, Harlan U. Anderson, Don M. Sparlin, M. M. Nasrallah Jan 1991

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 …


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 Jan 1991

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 Jan 1991

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 …