Materials Science and Engineering Commons^™

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.

Q Improvement Of A 5.2 Ghz Te011 Cavity By Incorporating Y1Ba2Cu3O7-X, R. Joseph Leclear

Electrical & Computer Engineering Theses & Dissertations

Research is undertaken to apply high temperature superconducting material to improve the quality factor (Q) of a 5.2 GHz cylindrical resonant cavity. In particular, the approach is to electrophoretically deposit polycrystalline Y₁Ba₂Cu₃O_7-x (YBCO) on the conducting surface of the cavity cylinder. Spalling of the YBCO ceramic coating due to expansion and contraction of the cavity during sintering and testing is overcome by segmenting the cylinder. Results show that the Q of the cavity is increased over that of a copper cavity at temperatures below 60 K. At 20 K, improvement exceeds a factor …

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. …

Toughening Mechanisms In Weak Matrix Ceramic Composites, Jowoong Ha

Doctoral Dissertations

"Tough behavior of ceramic matrix composites is closely related to the weak interface between fiber and matrix. The weak interfaces in composites have been provided by reducing the chemical bonding and the residual thermal stresses between constituents. A new way to introduce the weak interface by induced porosity or damaged zones, so called porosity toughening or damage toughening respectively, was proposed in this study to provide the rationale for guiding development of oxide/oxide composites. The existence of porosity toughening was examined by qualitative theoretical consideration and experiments. Porous oxide/oxide composites were fabricated using alumino-silicate fibers (Nextel 440) and magnesium alumino-silicate …

Recent Applications Of Glass Science, Norbert J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

Recent, often exciting, applications of glass science include solid state batteries, electronic switches and memories, electrophotography, solar cells, microspheres for optical strengthening and medical uses, novel glass ceramics such as machinable and bioactive materials, solder glasses, composites, sol-gel glasses, gradient index optics, communication fibers, sensors, non-linear and active optics, and, perhaps, digital optics. The large field of special coatings is not covered in this review. © 1990.

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 arithmetic joints in a mammal comprise 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. Methods for preparing such microspheres and for carrying out radiation synovectomy of arthritic joints utilizing such microspheres are also disclosed.

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.

Sessile Drop Studies Of Aluminum On Sapphire, Ke Wen K. Li

Masters Theses

A sessile drop technique employing a drop placement method has been used to investigate the wetting behavior and interfacial phenomena between aluminum and single crystal α-alumina. Measurements were made under a flowing mixture of H₂ and He atomsphere from 1200°C to 1600°C. Acute contact angles decreased continuously in all cases during the 8-hour experimental time. Neither the oxygen partial pressure of the flowing gas nor the orientation of the single crystal alumina substrate affected the contact angles, but the shapes of crystals grown at the substrate-metal interfaces were dependent on the orientation of the substrate surface to some extent. …

Processing And Characterization Of Ceramic Fiber Reinforced Porous Matrix Composites, Wen-Chiang Tu

Masters Theses

"The development of ceramic fiber reinforced ceramic matrix composites has been shown to be a promising approach for high toughness ceramic materials. The purpose of this work was to develop a new ceramic matrix composite(CMC) system based on a porous mullitic matrix reinforced with ceramic fibers. Unidirectional alligned fiber reinforced mullitic matrix composites were fabricated by a filament winding process. Prepregs were laminated and thermal processed in air. SEM fractographs of the composites were characterized and related to the observed load-deflection behaviors under 3-point flexure. The fracture surface expositions changed from extensive fiber tear-out to limited fiber pull-out as the …

The Effect Of Additives On Properties Of Pfn-Pfw Dielectric Materials, Weih-Min Liao

Masters Theses

"The purpose of this study was to investigate the effect of processing and additives on the properties of the Pb(Fe_1/2Nb_1/2)O₃-PB(Fe_2/3W_1/3)O₃ solid solutions. The basic composition was 70 m% Pb(Fe_1/2Nb_1/2)O₃ and 30 m% Pb(Fe_2/3W_1/3)O₃. The additives used were MnO, PbO and ZnNbO₆. Pressed compacts were sintered over the temperature range 900'C to 1050°C for 1 to 5 hours.

The influence of processing and composition on the properties was determined by measurement of density, shrinkage, dielectric constant, dissipation factor and …

Glass Formation And Properties In The Sm₂O₃·Al₂O₃·Sio₂ System, Erik M. Erbe

Masters Theses

"The purpose of this investigation was to develop a samarium containing aluminosilicate glass with properties suitable for use in the treatment of rheumatoid arthritis. Microspheres made from these compositions would be neutron activated to produce radioactive Sm-153 which has beta-particle energies suitable for treating rheumatoid arthritis as well as appropriate gamma-ray emission for nuclear imaging. The properties of Sm₂O₃ · AI₂O₃ · SiO₂ glasses containing 10 to 25 mole% Sm₂O₃ were evaluated as a function of composition. The density, refractive index, thermal expansion coefficient, and microhardness increased with increasing Sm …

The Effect Of Phosphate Additives On Alumina, Alumina-Calcia, Alumina-Silica Refractory Castable Systems, Sukendro Widjaja

Masters Theses

The effects of the addition of phosphate chemicals to Al₂O₃, Al₂O₃-CaO, and Al₂O₃-SiO₂ systems have been studied concentrating on selected dry and fired properties. The various refractories evaluated were formulated from all alumina aggregate systems based on 1) a mix of tabular and calcined fine aluminas, 2) a combination of calcium aluminate cement bonded-tabular and calcined fine aluminas, and 3) an alumina aggregate-silica fume mixture. Specimens were vibration-cast, dried at 110°C and fired at 1450°C. It was found that each system has different property responses to different …

Fabrication And Mechanical Property Analysis Of A Transparent, Glass Fiber Reinforced Polymer Matrix Composite, James R. Olson

Masters Theses

"A "transparent” composite was produced by reinforcing poly(methyl methacrylate) (PMMA) with unidirectional borosilicate glass fibers. Composites with 40 volume percent fiber had a modulus of rupture of 600 MPa which is six times greater than that of pure PMMA. Young's modulus for the same composite was 18 MPA which is nine times greater than the 2 MPa measured for pure PMMA. Work of fracture was 110 kJ/m² or more than double the 45 kJ/m² required to fracture pure PMMA. The optical transmission of the composite with 30 volume percent fiber was approximately 40 percent through a 10 mm …

Glass Fiber Reinforced Polycarbonate Composites, Wen Ching Hu

Masters Theses

"The purpose of this work was to develop a transparent glass fiber reinforced polymer composite material which is superior to the transparent unreinforced thermoplastic in mechanical properties but similar in optical clarity. Polycarbonate matrix composite specimens containing 0 to 40 wt% SK-12 glass fiber were studied, with mechanical and optical properties determined as a function of glass fiber content. The mechanical properties -- flexural strength and elastic modulus increased with increasing glass fiber content. The optical properties -- transmission and transparency decreased with increasing glass fiber content. The factors which influence the mechanical and optical properties were investigated"--Abstract, page ii.

The Interfacial Phenomena Of Liquid Copper Of Sapphire Substrates, Jenq Liu

Masters Theses

"The wetting behavior of liquid copper on the sapphire is effected by the crystallographic orientation of the solid surface, the oxygen partial pressure, and the temperature. Each of these influences has been studied by the sessile drop technique, over the oxygen partial pressure range from 10^-2 to 10^-20 atm at temperatures of 1373°K, and 1523°K. The effect of oxygen partial pressure on the liquid copper surface energy follows the Gibbs Langmuir Law.

The crystallographic orientation of the sapphire surface causes variations in the contact angle. This is more significant for higher oxygen partial pressure, but is eliminated at …

The Effect Of Excess Lead Oxide On The Sintering Characteristics And Dielectric Properties Of Lead Magnesium Niobate Ceramics, Dyllan Jye-Lun Hong

Masters Theses

"The effect of lead oxide additions on sintering characteristics and dielectric properties of ferroelectric Pb₃MgNb₂O₉ based capacitors was studied. The basic dielectric compositions were formed by solid state reaction. Densification was studied as a function of PbO content over the temperature range 900 °C to 1000 °C for sintering times one to six hours depending on the amount of additive, and the sintering temperature.

Weight loss, density and shrinkage measurements of each composition were made in order to relate the effects of the excess PbO additions on the densification. The dielectric and electrical properties were …

The Development Of Glass-Ceramic Matrix Composites And The Crystallization Of Two Glass-Ceramic Matrices, William M. Carty

Masters Theses

"In order to develop ceramic matrix composites for high temperature applications, two glass-ceramic matrices, one an yttrium aluminosilicate (YAS), the other a magnesium aluminosilicate (cordierite), were chosen as possible matrix compositions. Two separate sets of experiments were performed. Specimens were hot pressed and heat treated then analyzed for the crystallization products and C.T.E. Specimens were also prepared containing commercially available ceramic fibers and coated ceramic fibers to investigate fiber/matrix interactions and the effect of fiber additions on the crystallization of the glass matrices. DTA was employed to approximate the crystallization temperature of the glasses and to determine the effect of …

Bubble Formation, Movement And Distortion In Viscous Glass, Simon Cheng-Ping Wang

Doctoral Dissertations

"A study of bubble formation, movement and distortion in viscous glass is described. A glass rod containing an irregularly shaped hole is heated to a temperature at where the glass viscosity is low enough to let the hole form a spherical bubble. Spheration occurs as the bubble moves upward in the glass rod. At the proper time, the rising bubble is decelerated and brought to a stop by increasing the glass viscosity by slowly reducing the temperature. The entrapped bubble is then cut from the glass rod and heated again, if necessary, to a lower temperature, to reduce distortion of …

Studies Of Defect Structure And Oxidation-Reduction Behavior Of Undoped Lamno₃, Sr-Doped Lamno₃ And Mg-Doped Lamno₃, Jen-Ho Kuo

Doctoral Dissertations

"Undoped LaMnO₃, Sr-doped LaMnO₃ and Mg-doped LaMnO₃ showed reversible oxidation-reduction behavior. These perovskites can be excess, stoichiometric or deficient in oxygen content depending on the specific conditions. Under very reducing conditions these oxides will decompose into new phases. Phase stabilities for these oxides were determined. The results showed that both Sr and Mg doping caused the LaMnO₃ to dissociate at higher oxygen activities than for undoped LaMnO₃.

Defect models were proposed to interpret the TG results, in which metal vacancies are assumed for the oxygen excess condition and oxygen vacancies are assumed for the oxygen deficient condition. Thermodynamic properties were …

Causal Factors In The Hydration Susceptibility Of Periclase Aggregates, Chao-Min Cheng

Masters Theses

"The findings presented in this thesis are the result of a study of the hydration mechanism of pre-calcined periclase aggregates. It is hoped that these findings will provide the means to develop an economical, stable and hydration resistant layer on the surface of periclase aggregates by coating with appropriate chemical systems.

In the conduct of this study two sources of commercially obtained materials, Steetley 323, and China metal 90-10, supplied by the Quigley company, were characterized and treated with different concentrations of boron-containing water suspensions in order to impose an altered layer which would resist hydration.

Variables affecting hydration investigated …

Property Survey Of Y₂O₃-Al₂O₃-Sio₂-MₓoY Glasses, Amy Lee Applewhite

Masters Theses

"The purpose of this work was to investigate the properties of Y₂O₃-Al₂O₃-SiO₂-M_xO_y glasses. Many M_xO_y components were tested, but TiO₂ and B₂O₃ proved the most interesting. Glasses containing 5 to 25 wt % TiO₂ were melted and found to have improved chemical durability and a higher refractive index and density than the eutectic Y₂O₃-Al₂O₃-SiO₂ starting glass. These glasses could be crystallized to form an opaque glass ceramic. Glasses containing B₂O₃ were formed by exchanging SiO₂ with B₂O₃ while holding the Y₂O₃ and Al₂O₃ content constant. The density, hardness, refractive index, transformation temperature, softening temperature …

An Apparatus For The Measurement Of Dc Electrical Conductivity And Seebeck Coefficient Of Semiconductors As A Function Of High Temperature And Oxygen Partial Pressure, George Francis Carini Ii

Masters Theses

"A computer controlled apparatus for the measurement of dc electrical conductivity and Seebeck coefficient as a function of temperature and oxygen partial pressure has been developed. Thermocouples are in electrical and thermal contact with the ends of the specimen bar. This allows both Seebeck and four-wire electrical conductivity measurements to be made in situ. Environmental enclosure of the specimen allows measurements over a range of oxygen activities from 1 to 10^-18 atm. A discussion of the measuring technique with schematics of the apparatus and data retrieval system is made. Results for measurements in selected oxide ceramics are compared to …

Discussion Of "Lime-Enhanced Reduction Of Sulfide Concentrates: A Thermodynamic Discussion", Arthur E. Morris, Harry Flynn

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Influence Of Oxygen Activity On The Lattice Parameters And Thermal Expansion Of Mg And Sr-Doped Lacro₃, Sutham Srilomsak

Masters Theses

"Lanthanum Chromite, when used as the fuel cell interconnector material is exposed to extremely different oxygen activities on its two surfaces. In addition, it must also form coherent boundaries with the fuel electrode (anode) and air electrode (cathode) layers. In order to accomplish these functions the acceptor doped LaCrO₃ must not only be chemically stable over large oxygen activity ranges, but also have good thermal expansion coefficient of match with both the anode and cathode. Therefore, the objective of this study is to investigate these requirements for Mg and Sr doped LaCrO₃. The study was divided into …

The Effect Of Oxygen Partial Pressure On Oxygen And Carbon Incorporation In Czochralski Grown Single Crystal Silicon, Paul Shane Carter

Masters Theses

"The study herein detailed was made to determine the effect of varying the oxygen partial pressure of a Czochralski type crystal pulling furnace using conventional hardware and remelt silicon on the level of incorporated oxygen and carbon in the single crystal. The oxygen partial pressure was measured by a zirconia type oxygen sensor and controlled by additions of hydrogen or carbon dioxide to the argon purge gas. The oxygen and carbon incorporation measurements were made by the Fourier Transform Infrared (FTIR) method, using the American Standard for Testing Materials (ASTM) standard calibration.

During the study boules which were zero dislocation …

An Investigation Of The Low Voltage Failure Mechanism In Multilayer Ceramic Capacitors, Christopher John Brannon

Masters Theses

"Enhanced leakage current was induced into multilayer ceramic capacitors by the introduction of micro-cracks. These cracks extended from the surface through the electrode layers and were formed by means of thermal shock. The capacitors were then exposed to a low voltage bias and a humid atmosphere. Results indicated that a simple electrolytic solution mechanism may be responsible for the increased conduction, and that the proposed dendritic growth mechanisms may be more complex than necessary"--Abstract, p. ii

Reply, Paul W. Angel, Chandra S. Ray, Delbert E. Day

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Glass Experiments In Space, Norbert J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

Current and potential glass research under microgravity includes studies of minimum cooling rate, homogeneous nucleation, diffusion, surface tension and enrichment, fining without buoyancy, avoidance of liquid phase separation, gel synthesis, composites and uniform micro balloons. The experiments do not just anticipate space fabrication but will also provide information and innovation encouraging advanced processing on earth. © 1986.

Oxidation Kinetics Of Polycrystalline Srtio₃ And Lacro₃, Chi-Kung Jerry Yu

Doctoral Dissertations

"The oxidation kinetics of polycrystalline SrTiO₃ and LaCrO₃ were determined by measuring the time and temperature dependence of the weight and conductivity change of reduced samples. A region of fast diffusion followed by a reduced diffusion tail was observed in the TGA measurements. This observation can be interpreted as the initial diffusion along the boundaries and then spreading out into the lattice. The absence of the tail in the conductivity measurements is due to the high electron and hole mobility at the boundaries. The electrical conductivity and TGA results on Nb-doped LaCrO₃ show that at low oxygen …

Dissolution Of Multi-Component Systems, Robin Ashley Murphy

Doctoral Dissertations

"The validity of ideal barrier layer diffusion kinetics was examined in the NaCl/KCl - glycerol and Al₂O₃-CaO-Al₂O₃-SiO₂/slag corrosion systems. Single crystals and dense polycrystalline plates of pure NaCl or KCl exhibit steady-state corrosion rates within 10%, of calculated theoretical values, while dense mixtures of the two salts corrode at rates higher than either pure material. The results are compared to the grooving phenomena of NaCl/KCl bicrystals.

Polycrystalline Al₂O₃ is shown to corrode at the same rate as single crystal sapphire at 1400°C in CaO-SiO₂-Al_{2 …}