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Materials Science and Engineering
Materials Science and Engineering Faculty Research & Creative Works
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- Steel Melting (2)
- Biomass Smoke (1)
- Calcium compounds (1)
- Carry-Over Slag (1)
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- Ceramic Slurries (1)
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- Dynamic Chemistry and Temperature Simulation (1)
- Electric Impedance (1)
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- Freeze-Spray (1)
- Grain boundaries (1)
- Heat transfer (1)
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- Humidification Factor (1)
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- Low Binder Content (1)
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Articles 1 - 13 of 13
Full-Text Articles in Engineering
Ac Conductivity Relaxation Processes In Cacu₃Ti₄O₁₂ Ceramics: Grain Boundary And Domain Boundary Effects, Wei Li, Robert W. Schwartz
Ac Conductivity Relaxation Processes In Cacu₃Ti₄O₁₂ Ceramics: Grain Boundary And Domain Boundary Effects, Wei Li, Robert W. Schwartz
Materials Science and Engineering Faculty Research & Creative Works
The ac conductivity of CaCu₃Ti₄O₁₂ ceramics associated with electrical charge carrier motion (ions or vacancies) was investigated as a function of frequency at different temperatures. The long range migration of charge carriers within the ceramic is restricted by two kinds of insulating barriers, namely, grain boundaries and domain boundaries. The potential barriers associated with these boundaries lead to two anomalies in conductivity response and three frequency-dependent contributions to conductivity: long range diffusion of carriers, carrier migration localized within grains, and carrier migration localized within domains.
Humidification Factors From Laboratory Studies Of Fresh Smoke From Biomass Fuels, D. E. Day, J. L. Hand, C. M. Carrico, Guenter Engling, W. C. Malm
Humidification Factors From Laboratory Studies Of Fresh Smoke From Biomass Fuels, D. E. Day, J. L. Hand, C. M. Carrico, Guenter Engling, W. C. Malm
Materials Science and Engineering Faculty Research & Creative Works
Measurements of smoke aerosol humidification factors were performed in a laboratory for different biomass fuel types and burn conditions. Two nephelometers simultaneously measured dry and humidified light scattering coefficients (bsp(dry) and bsp(RH), respectively), providing the first observations of the temporal evolution of the humidification factor (f(RH) = bsp(RH)/bsp(dry)) for fresh (minutes-old) smoke. Hygroscopic characteristics of the smoke aerosols varied with fuel type and fire conditions, with the mean f(RH) ranging from 1.01 to 1.95 for fresh minutes-old smoke for the relative humidity (RH) range of 70-94%. These f(RH) values exhibited temporal variability, with some fuels alternating from hygroscopic to nonhygroscopic …
Freeze-Spray Processing Of Layered Ceramic Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan
Freeze-Spray Processing Of Layered Ceramic Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
Thermal gradients and associated stresses are critical in designing with ceramic composites having low thermal conductivity. In order to reduce the stresses from thermal gradients, compositional gradients are employed in designing of composite structures. This study addresses development of freeze-spray process to fabricate layered ceramic structures with controlled layer thickness and microstructural development. The composites were processed by spraying of ceramic slurries with low binder content and relatively high solids loadings (up to 40 vol%) on a cooled substrate. The frozen parts were freeze-dried and sintered at elevated temperatures. The relationship between microstructural development and thermal expansion behavior of Al …
Method For Fabricating Nanostructured Solid Oxide Fuel Cells And Cell Components, Harlan U. Anderson, X.-D. Zhou, Wayne Huebner
Method For Fabricating Nanostructured Solid Oxide Fuel Cells And Cell Components, Harlan U. Anderson, X.-D. Zhou, Wayne Huebner
Materials Science and Engineering Faculty Research & Creative Works
A method of fabricating a nanostructured solid oxide fuel cell includes dispersing ceria and doped ceria nanoparticles in a first colloidal solution, atomizing the first colloidal solution into a spray, depositing the spray onto a substrate to form a thin film electrolyte, dispersing a nanocomposite powder including ceria and CuO in the first solution, forming a second colloidal solution, atomizing the second colloidal solution into a second spray, and depositing the second spray over the thin film electrolyte as an interfacial layer.
Method Of Preparing A Solid Oxide Fuel Cell, Greg Hilmas, Dustin Beeaff
Method Of Preparing A Solid Oxide Fuel Cell, Greg Hilmas, Dustin Beeaff
Materials Science and Engineering Faculty Research & Creative Works
A solid oxide fuel cell having a multichannel electrode architecture and method for preparing the same, the method including forming a first carbon laden composition, including a first thermoplastic binder, into a rod, applying a first zirconia laden composition, including a second thermoplastic binder, onto the rod to form a composite feed rod, extruding the composite feed rod to form a controlled geometry filament, bundling the extruded composite feed rod to form a multicellular feed rod, extruding the multicellular feed rod to form a multicellular rod, cutting the multicellular rod into multicellular discs, applying a zirconia laden material to one …
Dielectric Constant Of Particles Determined By Impedance Spectroscopy, Vladimir Petrovsky, Abhishek Manohar, Fatih Dogan
Dielectric Constant Of Particles Determined By Impedance Spectroscopy, Vladimir Petrovsky, Abhishek Manohar, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
Electrical characterization of slurries prepared by mixing dielectric powders with solvents can be used to estimate dielectric properties of the particles. In particular, dielectric constant of the particles can be calculated from effective dielectric constant of the slurry measured at high frequency by using the Lorentz-Lorenz or similar equations based on mixing rules. Unfortunately, this approach leads to high margin of errors in dielectric constant estimation and is very sensitive to any slurry nonidealities such as sedimentation or agglomeration of particles. Impedance spectroscopy techniques are introduced to measure dielectric properties of particles at different frequency ranges. Dielectric constant of strontium …
Simulations Of A New Continuous Steelmaking Process, Jorg Annie Peter, Kent D. Peaslee, D. G. C. Robertson
Simulations Of A New Continuous Steelmaking Process, Jorg Annie Peter, Kent D. Peaslee, D. G. C. Robertson
Materials Science and Engineering Faculty Research & Creative Works
A new continuous steelmaking process has been designed in an effort to reduce meltshop costs and increase productivity beyond the possibilities of current EAF-LMF-CC meltshops. This paper discusses possible operational performance based on industrially-verified kinetic, thermodynamic, and heat-transfer models. Dynamic simulations predict variations in steel chemistry and temperature, resulting from steel treatment and upsets. Savings in costs are projected because of increased metallic yield, lower energy requirements, more efficient use of deoxidants and alloys, fewer man-hours per ton, and decreased capital investment.
Method For Preparation Of Nanometer Cerium-Based Oxide Particles, X.-D. Zhou, Wayne Huebner, Harlan U. Anderson
Method For Preparation Of Nanometer Cerium-Based Oxide Particles, X.-D. Zhou, Wayne Huebner, Harlan U. Anderson
Materials Science and Engineering Faculty Research & Creative Works
The invention comprises novel undoped and doped nanometer-scale CeO2 particles as well as a novel semi-batch reactor method for directly synthesizing the novel particles at room temperature. The powders exhibited a surface area of approximately 170 m2/g with a particle size of about 3-5 nm, and are formed of single crystal particles that are of uniform size and shape. The particles’ surface area could be decreased down to 5 m2/g, which corresponds to a particle size of 100 nm, by thermal annealing at temperatures up to 1000° C. Control over the particle size, size distribution …
Structural And Magnetic Properties Of La Mn₁₋ₓfeₓo₃ (0 < X < 1.0), X.-D. Zhou, L. R. Pederson, Qingsheng Cai, Jinbo Yang, B. J. Scarfino, M. Kim, William B. Yelon, William Joseph James, Harlan U. Anderson, C. Wang
Structural And Magnetic Properties Of La Mn₁₋ₓfeₓo₃ (0 < X < 1.0), X.-D. Zhou, L. R. Pederson, Qingsheng Cai, Jinbo Yang, B. J. Scarfino, M. Kim, William B. Yelon, William Joseph James, Harlan U. Anderson, C. Wang
Materials Science and Engineering Faculty Research & Creative Works
Electronic, structural, and magnetic properties of Mn-doped lanthanum ferrites were studied by neutron diffraction, superconducting quantum interference device, and impedance spectroscopy. Neutron diffraction refinements were performed with the constraint of full La occupancy, which showed the presence of excess oxygen when x < 0.4. Mixed valent Mn cations and cation vacancies, therefore, exist in all the samples. The samples with x > 0.7 are magnetically ordered at room temperature with orthorhombic symmetry (Pbnm). When x < 0.3 the structure is rhombohedral and magnetically disordered above 16 K. The majority carriers, electron holes, correspond to high oxidation states of Mn. The carrier concentration is determined from the Seebeck coefficients, and is a function of temperature and Fe concentration. The measurements of conductivity and Seebeck coefficients show polaron hopping at elevated temperatures.
Improving Melting Efficiency Through The Application Of New Refractory Materials, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, Todd P. Sander, Jeffrey D. Smith, Mangesh Vibhandik
Improving Melting Efficiency Through The Application Of New Refractory Materials, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, Todd P. Sander, Jeffrey D. Smith, Mangesh Vibhandik
Materials Science and Engineering Faculty Research & Creative Works
Ladle design and ladle practices have a significant effect on a foundry operation and product quality. Large steel temperature losses or instabilities in the pouring temperature are frequently compensated by tapping at higher temperatures dramatically increasing furnace and ladle lining wear, oxidation of the steel, alloying element losses, and energy consumption in steel melting. Ladle lining materials need to satisfy a complex array of often conflicting requirements. For example, ceramic materials for linings must possess a high strength at liquid steel temperatures to prevent erosion and crack formation. However, linings need to also have a low thermal conductivity which typically …
Vibration Testing Of Repaired Lead-Tin/Lead-Free Solder Joints, Matthew O'Keefe, S. Vetter, D. Murry, J. Smith, P. Amick, Martin G. Perez, D. W. Kleine, Richard S. Colfax
Vibration Testing Of Repaired Lead-Tin/Lead-Free Solder Joints, Matthew O'Keefe, S. Vetter, D. Murry, J. Smith, P. Amick, Martin G. Perez, D. W. Kleine, Richard S. Colfax
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Decreasing Electrical Energy Consumption Through Sic Additions, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, John Carpenter, Chen Wang
Decreasing Electrical Energy Consumption Through Sic Additions, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, John Carpenter, Chen Wang
Materials Science and Engineering Faculty Research & Creative Works
This paper summarizes results of industrial experiments investigating the introduction of supplemental chemical energy in Electric Arc Furnaces (EAF). Specifically, this research evaluates the effects of adding 0.4-0.6% of the scrap charge weight as SiC (10 lbs per scrap ton charged) in the EAF. SiC additions increase the available exothermic reactions during oxygen boiling in an attempt to reduce the electrical energy requirements. Results from 180 trial heats at two different steel foundries are highlighted and statistically evaluated. In both cases, the SiC additions had a measurable effect on decreasing the electrical energy consumption.
Crystal And Electronic Structures Of Linh₂, Jinbo Yang, X.-D. Zhou, Qingsheng Cai, William Joseph James, William B. Yelon
Crystal And Electronic Structures Of Linh₂, Jinbo Yang, X.-D. Zhou, Qingsheng Cai, William Joseph James, William B. Yelon
Materials Science and Engineering Faculty Research & Creative Works
The crystal structure of LiNH2 was reinvestigated using powder neutron diffraction with high sensitivity. The compound crystallizes in the tetragonal space group I4 with lattice parameters α = b= 5.034 42 (24) Å, c = 10.255 58 (52) Å. It is found that H atoms occupy 8g1(0.2429, 0.1285, 0.1910) and 8g2 (0.3840, 0.3512, 0.1278) sites. The bond lengths between the nearest nitrogen and hydrogen atoms are 0.986 and 0.942 Å, respectively. The bond angle between H-N-H is about 99.97°. These results are significantly different from those of previous experiments. The electronic structure was calculated according to the revised structural …