Digital Commons Network^™

Solution-Based Synthesis Of Nitride Fuels, Kenneth Czerwinski, Thomas Hartmann

Fuels Campaign (TRP)

A wide variety of fuel concepts are considered for advanced reactor technology including metals, metal oxides or metal nitrides as solid solutions or composite materials. Nitride fuels have appropriate properties for advanced fuels including high thermal conductivity, thermal stability, solid-state solubility of actinides, fissile metal density, and suitable neutronic properties. A drawback of nitride fuels involves their synthesis. A key parameter for preparing oxide fuels is the precipitation step in the sol-gel process. For nitride fuels, the current synthetic route is carbothermic reduction from the oxide to the nitride. This process step is based on solid phase reactions and for …

Afci Quarterly Input – Unlv October 1 Through December 31, 2005, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Atr-Ftir Spectroscopic Analysis Of Sorption Of Aqueous Analytes Into Polymer Coatings Used With Guided Sh-Saw Sensors, Yolanda K. Jones, Zhonghui Li, Michael M. Johnson, Fabien Josse, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

Attenuated total internal reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used for the investigation of sorption of aqueous solutions of analytes into polymer coatings. A series of simple model polymers, such as poly(dimethylsiloxane), poly(epichlorhydrin), and poly(isobutylene), and films and analytes, such as aqueous solutions of ethylbenzene, xylenes, toluene, and nitrobenzene, were used to evaluate the use of ATR-FTIR spectroscopy as a screening tool for sensor development. The ratios of integrated infrared absorption bands provided a simple and efficient method for predicting trends in partition coefficients. Responses of polymer-coated guided shear horizontal surface acoustic wave (SH-SAW) sensor platforms to the series …

Transport And Kinetics Of Aromatic Hydrocarbons Into Micron-Sized Liquid Droplets: With Applications To Atmospheric Chemistry, Suresh Raja

LSU Doctoral Dissertations

In the natural process of wet deposition, gas-water interfaces play an important role in the transport of chemical contaminants in the atmosphere via fog, rain and cloud drops. Evidences from several other works point out deviations in gas-liquid partitioning as predicted by Henry’s law. Uptake and mass transfer of benzene, naphthalene, and phenanthrene was chosen to study in a falling droplet train apparatus. Higher droplet-to-vapor partition constant (KDV) was noted for diameters less than 200ìm and was attributed to surface adsorption and accumulation. Mass transfer of phenanthrene was dependent on gas-phase diffusion and mass accommodation at the interface, while the …

Slurry Chemistry Effects On Copper Chemical Mechanical Planarization, Ying Luo

Electronic Theses and Dissertations

Chemical-mechanical Planarization (CMP) has emerged as one of the fastest-growing processes in the semiconductor manufacturing industry, and it is expected to show equally explosive growth in the future (Braun, 2001). The development of CMP has been fueled by the introduction of copper interconnects in microelectronic devices. Other novel applications of CMP include the fabrications of microelectromechanical systems (MEMS), advanced displays, three dimensional systems, and so on (Evans, 2002). CMP is expected to play a key role in the next-generation micro- and nanofabrication technologies (Singh, et al., 2002). Despite the rapid increase in CMP applications, the fundamental understanding of the CMP …

Interaction Effects Of Slurry Chemistry On Chemical Mechanical Planarization Of Electroplated Copper, Peter A. Miranda, Jerome A. Imonigie, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

Recent studies have been conducted investigating the effects of slurry chemistry on the copper CMP process. Slurry pH and hydrogen peroxide concentration are two important variables that must be carefully formulated in order to achieve desired removal rates and uniformity. In applications such as throughwafer vertical interconnects, slurry chemistry effects must be thoroughly understood when copper plating thicknesses can measure up to 20 microns thick. The species of copper present on the surface of the wafer can be controlled through formulation of the slurry chemistry resulting in minimizing non-uniformity while aggressively removing copper. Using a design of experiments (DOE) approach, …

Introduction To Pollution Prevention Concepts In Freshman Chemistry Through Simulations And Hypermidia, Aniraban Bhaumik

Theses

As citizens of the 20th century, a key issue we all are aware of is degradation of the environment. In the interest of teaching the environmental issues to freshmen engineers, this study develops a computer aided learning/teaching (CAL/T) tool.

This CAL/T tool consists of Internet based multimedia courseware and intelligent simulations. The courseware assembles the fundamentals of chemistry associated with current environmental issues such as air pollution, stratospheric ozone layer depletion and environmentally sensitive or 'clean' manufacturing. The courseware targets early and comprehensive understanding of pollution prevention concepts with a focus on environmentally friendly manufacturing. The courseware includes: on-line text, …

Remediation And Reuse Of Chromium Contaminated Soils Through Cold Top Ex-Site Vitrification, Wiwat Kamolpornwijit

Theses

More than 150 sites in Hudson County, New Jersey are identified as chromium contaminated sites. Hexavalent chromium, highly soluble in water, is considered as an environmental and health hazard, classified as a group A human carcinogen. In this research, the feasibility was performed to study the possibility of remediation of chromium contaminated soil by ex-situ vitrification and to evaluate reuse potential of vitrified products as highway construction aggregate. A series of physical and chemical analysis was conducted on nine soil samples collected from different chromium contaminated sites. Results were analyzed for their compatibility for vitrification. Sand and carbon were added …

Influence Of Formation Processes On Oblique Detonation Wave Stabilization, K. Ghorbanian, J. D. Sterling

Business and Information Technology Faculty Research & Creative Works

In this article we report steady, two-dimensional, inviscid solutions for the near field and far field of a supersonic reactive flow over a variable-double-ramp geometry. The incident shock wave compresses and heats the reactants that will combust after flowing some induction length. Upon reaction, a detonation wave forms and intersects the leading wave at some distance from the ramp surface. In this article, reaction-polar diagrams are developed, and the detonation branch solutions are used to investigate the wave interaction processes that may lead to a steady three-wave structure. By considering this formation process new oblique detonation wave stabilization criteria based …

Atomic And Molecular-Perspectives In Electrochemical Interfaces, Zhaowu Tian

Journal of Electrochemistry

The following recent studies on the atomic and molecular-perspectives at electrochemical interfaces using Raman, IR, STM and quantum chemical methed by electrochemistry group in Xiamen University are briefly reviewed. 1.Orientation, charge transfer and bonding of adsorbed molecules. 2. Adsorption effect, electrode potential effect and adatom effect on the electron populations and strength of intramolec ular bonds of the adsorbed molecules. 3. Detailed classification into various types (e. g., competitive, chemically inductive, physical inductive etc.) of coadsorption on electrodes according to the above-mentioned effects.  4. Single crystal face structure effect and adatom effect on the kinetics and the mechanisms of electrocatalytic …

A Radiant Flow Reactor For High-Temperature Reactivity Studies Of Pulverized Solids, John C. Chen, Stephen Niksa

Mechanical Engineering

Our radiant two‐phase flow reactor presents several new possibilities for high‐temperature reactivity studies. Most importantly, the thermal histories of the suspension and entrainment gas can be independently regulated over wide ranges. At low suspension loadings, outlet temperatures can differ by hundreds of degrees and gas temperatures are low enough to inhibit hydrocarbon cracking chemistry, so primary products are quenched as soon as they are expelled. With coal suspensions, tars were generated with the highest H/C ratio and lowest proton aromaticity ever reported. Alternatively, particles and gas can be heated at similar rates to promote secondary chemistry by increasing particle loading. …

Suppressed Nitrogen Evolution From Coal-Derived Soot And Low-Volatility Coal Chars, John C. Chen, Stephen Niksa

Mechanical Engineering

This laboratory study uses a novel furnace to resolve nitrogen evolution during the three stages of pulverized coal combustion: primary devolatilization, secondary pyrolysis, and combustion. The behavior of six coals depicts continuous rank variations, as well as suppressed nitrogen evolution from low volatility coals. During primary devolatilization of any coal, aromatic compounds in tar and oils are virtually the only shuttles for nitrogen out of the coal matrix. The small amounts of HCN observed while primary devolatilization winds down probably come from the char, because char particles are significantly hotter than tar in these experiments. Secondary pyrolysis promotes additional HCN …

Analysis Of Nitrated Polycyclic Hydrocarbons, Pah-Quinones And Related Compounds In Ambient Air, Yalan Wang

Theses

Studies were conducted to characterized airborne particulate extractable organic matter (EOM) with respect to chemical composition and biological activity. It has been well established that the nitrated polycyclic hydrocarbons (nitroPAH) are environmental contaminants. To identify nitro-PAH in ambient air sample, a technique was developed involving introduction of a reducer column into an reversephase high performance liquid chromatography (HPLC) system. Strong fluorescence signals were achieved from nitro-PAH and detected together with u.v. signals for the qualitative and quantitative analysis of nitro-PAH. 2-Nitrotriptycene was synthesized according to published procedures and used as an internal standard. By use of the above technique, 9nitroanthracene, …

Reconnaissance Of Sediment-Phosphorus Relationships In Some Utah Reservoirs, Jay J. Messer, Jean M. Ihnat

Reports

Introduction: Phosphorus inputs to lakes and reservoirs from tributary streams and non-point sources are well-known contributors to nuisance algal growths that degrade water quality for potable and recreational uses in lakes and reservoirs. However, phosphours inputs to the euphotic zone may also occur from within the lake itself, as a result of releases from both oxic and anoxid sediments. Such releases may originate from phosphorus inputs to a lake or reservoir during high runoff periods in the previous winder or spring, or they may represent phosphorus trapped in the sediment many years earlier, when phosphorus contributions from natural or anthropogenic …

Effects Of Multiple Scattering And Surface Albedo On The Photochemistry Of The Troposphere, Tommy Reinhold Robert Augustsson

Mechanical & Aerospace Engineering Theses & Dissertations

A one-dimensional photochemical model of the troposphere containing the species of the nitrogen, oxygen, carbon, hydrogen, and sulfur families has been developed and used to investigate the vertical profiles and the natural (including atmospheric chemical reactions) and anthropogenic sources and sinks of these species. The species continuity equations are solved numerically applying prescribed boundary conditions. The vertical flux is simulated by use of the parameterized eddy diffusion coefficients. Heterogeneous losses (e.g. rainout, gas-to-particle chemistry, and dry deposition), are parameterized to make calculated profiles consistent with measurements. The photochemical model is coupled to a radiative transfer model that calculates the radiation …

Electroless And Chemical Metal Deposition On Human Tooth Enamel., Richard Doyle Christie

Masters Theses

"Initial investigations have confirmed the feasibility of depositing an adherent metal film onto tooth enamel. Such films might be used as pit and fissure sealants in preventive dentistry, with denture or orthodontic work, as an intermediate substrate with various organic or inorganic restorative materials, or other such areas. The process employs chemical solutions containing ions of the metal to be deposited and suitable reducing agent solutions.

To date, metallic copper and silver films have been plated onto teeth in vitro. The deposits are quite adherent and appear to exhibit the conductivity, crystal structure, luster, hardness, and other chemical and physical …