Materials Science and Engineering Commons^™

Effect Of Nozzle Base Material On The Rate Of Clogging During The Continuous Casting Of Aluminum-Killed Steels, Luis Trueba, Kent D. Peaslee, Jeffrey D. Smith, Musa Karakus

Materials Science and Engineering Faculty Research & Creative Works

One approach to solving the problem of nozzle clogging during the continuous casting of aluminum-killed steels is through careful selection of nozzle materials. in this study, the rate of clogging was measured while casting steel through simulated nozzles produced from alumina, zirconia, magnesia, zirconia-graphite, and alumina-graphite - three common base materials and two common carbon-containing nozzle materials. Spent nozzles were characterized using optical and cathodoluminescence microscopy. Interactions between the nozzles and steel were not observed in the alumina, zirconia, and zirconia-graphite nozzles. Slight interactions were observed in the magnesia nozzles as alumina inclusions within the steel interacted with the nozzle …

Effect Of Welding Parameters On Properties Of 5052 Al Friction Stir Spot Welds, T. A. Freeney, S. R. Sharma, Rajiv S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Effect of process parameters on friction stir spot welding (FSSW) of 5052 Al alloy has been evaluated. a plunge type FSSW machine was used for this study. Sheet thicknesses of 1 and 1.6mm were used. the tool rotation rate was varied between 1000 and 3000 rpm. the tool plunge rate and dwell time was varied to give weld cycle of 1-4 seconds. Shear tests were performed in 2 sheet and 3 sheet configurations to determine the influence of processing parameters on the mechanical properties of lap joint FSSWs. Higher joint strengths were observed at lower tool rotation rates. Copyright © …

Redox Stable Electrodes For Hydrogen Producing Solid Oxide Electrolyzer, Yong Wook Sin, Vladimir Petrovsky, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

This report focuses on a study which measured the electrical conductivity of LSCrM, LSCr and LSM as a function of oxygen activity and temperature to evaluate the chemical and mechanical stability of the materials as an electrode in a solid oxide fuel-fed electrolyzer cell (SOFEC). the LSCrM symmetrical cell was fabricated using La_0.75Sr_0.25Cr_0.5Mn_0.5O₃ (LSCrM) powder and evaluated using electrical conductivity, impedance spectroscopy, current density and power density as a function of temperature. during the evaluation, symmetrical cell tests and fuel cell tests were performed as a function of temperature. Silver (Ag) …

Fabrication Of Array Microstructures By Localized Electro-Deposition, Nidal Khalaf Alshwawreh

Theses

Localized Electro-Deposition (LED) is now highly receiving scientists and researchers attention for its advantages over conventional fabrication techniques. These advantages include simplicity of the setup thus reducing the overall fabrication cost, capability of producing 2D and 3D high aspect ratio microstructures and its ability to fabricate microstructures from various raw materials. Efforts now are taking place in order to standardize the fabrication by LED to develop a commercial setup that is capable of producing complex microstructures which, in tum, can be integrated in different applications including microelectronics, microelectrochemical systems (MEMS) and sensors applications. The standardization process is performed by studying …

Growth Of Ge Quantum Dots On Si(100)-(2×1) By Pulsed Laser Deposition, M. S. Hegazy, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Self-assembled germanium quantum dots (QDs) were grown on Si(100)-(2×1) by pulsed laser deposition. In situ reflection-high energy electron diffraction (RHEED) and postdeposition atomic force microscopy are used to study the growth of the QDs. Several films of different thicknesses were grown at a substrate temperature of 400 °C using a Q-switched Nd:yttrium aluminum garnet laser (λ= 1064 nm, 40 ns pulse width, 23 J/cm ² fluence, and 10 Hz repetition rate). At low film thicknesses, hut clusters that are faceted by different planes, depending on their height, are observed after the completion of the wetting layer. With increasing film thickness, …

An Investigation Into Microwave Energy To Soften Scrap Tire Rubber Aiding Existing Mechanical Separation Processes, Russell Jon Lucas

Dissertations and Theses @ UNI

This research was performed to soften scrap tires to aid in their transformation from whole tires to valuable streams of rubber and steel for reuse in industry. Actual shredded scrap rubber was used in this experiment to determine if this highly variable material could yield consistent results if subjected to volumetric heating from a magnetron emitting microwave energy.

A consumer microwave oven was used to heat this material. This oven had its control circuitry modified by using a programmable logic controller to operate the energy exposure time. The sample's surface temperature was measured utilizing a non contact infrared thermometer. All …

Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum

Chemistry Faculty Research & Creative Works

For a polymer film deposited on a surface, the strength of the surfacesegment interaction affects the mobility of polymer-chain segments. The selfconsistent field lattice model of Scheutjens and Fleer,1 based on mean-field lattice models of polymer at interfaces,2 has been used to describe the distribution of conformations of polymers on surfaces. Adsorbed-polymer segments may be classified as belonging to loops, trains or tails. There are different techniques used to study the molecular motion of the polymer including modulated differential scanning calorimetry (MDSC)3 and nuclear magnetic resonance (NMR).4,5 in this work, solid-state deuterium (2H) NMR was used to characterize the polymer …

Designing And Modeling Of A New Continuous Steelmaking Process, Jörg Peter

Doctoral Dissertations

"Continuous steel production has the potential to lower the cost of steelmaking as compared to current batch operations. However, experiences from past attempts to develop and commercialize continuous steelmaking processes show that there are several engineering hurdles to overcome. The objective of this research was the development of a fully continuous steelmaking process that would incorporate the lessons from past experiences, address the foreseen challenges, and meet the requirements to justify the possible replacement of the current EAF-LMF steelmaking route.

The design of the new process consists of five interconnected vessels. Preheated scrap would be continuously charged, melted, and superheated …

Microwave Modeling And Characterization Of High-Tc Superconducting Thin Films, Thamer Mousa Badarneh

Theses

Because of the high critical temperature (Tc) that the new superconductors can reach, thin films can be used in a number of technological applications. One of the major applications of thin films is in the microwave devices, where superconducting strips are used as resonators, filters, delay lines, etc. The importance of the superconductors resides in the low losses incurred during the transmission along the strip. For example, the surface resistance of a high-Tc superconductor is at least one order of magnitude less than a similar one made of ordinary conductors. Because of this advantage, there is an increase in the …

Selective Growth Of Carbon Nanotubes And Oxide Nanowires: Applications In Shadow Lithography And Fabrication Of Aligned Carbon Nanotube Membranes, Nitin Chopra

University of Kentucky Doctoral Dissertations

A promising approach investigated here is to utilize thin film multilayer structures where the thickness of a catalyst layer at an exposed edge of photolithographically defined pattern determines the diameter of the nanotubes/nanowires grown from it. This can in turn be incorporated into photolithographically defined post structures resulting in an array of suspended nanowires for line-of-site shadow lithography. Success of the diameter control approach has been shown by selectively growing carbon nanotubes (CNTs) from narrow lines (12-60 nm) of SiO₂, Fe, Ni, Co on micron-scale patterned substrates in a ferrocene or nonferrocene catalyzed CVD process. In addition, the …