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2004

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Articles 121 - 150 of 480

Full-Text Articles in Chemistry

A Novel Role For The Immunophilin Fkbp52 In Copper Transport, Reiko Sanokawa-Akakura, Huachang Dai, Shin Akakura, David Weinstein, J. Eduardo Fajardo, Steven E. Lang, Scott Wadsworth, John Siekierka, Raymond B. Birge Jul 2004

A Novel Role For The Immunophilin Fkbp52 In Copper Transport, Reiko Sanokawa-Akakura, Huachang Dai, Shin Akakura, David Weinstein, J. Eduardo Fajardo, Steven E. Lang, Scott Wadsworth, John Siekierka, Raymond B. Birge

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

FK506-binding protein 52 (FKBP52) is an immunophilin that possesses peptidylprolyl cis/trans-isomerase (PPIase) activity and is a component of a subclass of steroid hormone receptor complexes. Several recent studies indicate that immunophilins can regulate neuronal survival and nerve regeneration although the molecular mechanisms are poorly understood. To investigate the function of FKBP52 in the nervous system, we employed a yeast two-hybrid strategy using the PPIase domain (domain I) as bait to screen a neonatal rat dorsal root ganglia cDNA expression library. We identified an interaction between FKBP52 domain I and Atox1, a copper-binding metallochaperone, Atox1 interacts with Menkes disease protein and …

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The Central Role Of Perilipin A In Lipid Metabolism And Adipocyte Lipolysis, John Tansey Jul 2004

The Central Role Of Perilipin A In Lipid Metabolism And Adipocyte Lipolysis, John Tansey

Chemistry Faculty Scholarship

The related disorders of obesity and diabetes are increasing to epidemic proportions. The role of neutral lipid storage and hydrolysis, and hence the adipocyte, is central to understanding this phenomenon. The adipocyte holds the major source of stored energy in the body in the form of triacylglycerols (TAG). It has been known for over 35 years that the breakdown of TAG and release of free (unesterified) fatty acids and glycerol from fat tissue can be regulated by a cAMP-mediated process. However, beyond the initial signaling cascade, the mechanistic details of this lipolytic reaction have remained unclear. Work in recent years …

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Finite Concentration Effects On Diffusion-Controlled Reactions, Chung Wong Jul 2004

Finite Concentration Effects On Diffusion-Controlled Reactions, Chung Wong

Chemistry & Biochemistry Faculty Works

The algorithm by Northrup, Allison, and McCammon has been used for two decades for calculating the diffusion-influenced rate-constants of enzymatic reactions. Although many interesting results have been obtained, the algorithm is based on the assumption that substrate-substrate interactions can be neglected. This approximation may not be valid when the concentration of the ligand is high. In this work, we constructed a simulation model that can take substrate-substrate interactions into account. We first validated the model by carrying out simulations in ways that could be compared to analytical theories. We then carried out simulations to examine the possible effects of substrate-substrate …

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Local Oxidation Of Metal And Metal Nitride Films, N Farkas, J. C. Tokash, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata Jul 2004

Local Oxidation Of Metal And Metal Nitride Films, N Farkas, J. C. Tokash, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Oxide growth on sputter-deposited thin films is studied on the local scale by atomic force microscope (AFM)-assisted lithography. We investigate the group IV reactive metals Zr, Hf, Ti, and their nitrides.-The nitrogen content of the deposition plasma affects the film crystal structure and electrical resistivity, which in turn alter the local oxidation rates. Mass transport plays an important role, producing features with heights ranging from a few nanometers up to hundreds of nanometers. The heights of the largest features are one to two orders of magnitude greater than observed in other material systems, and the growth is well controlled. We …

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Surface Composition And Structure Of Co3O4(110) And The Effect Of Impurity Segregation, S.C. Petitto, Marjorie Langell Jul 2004

Surface Composition And Structure Of Co3O4(110) And The Effect Of Impurity Segregation, S.C. Petitto, Marjorie Langell

Marjorie A. Langell Publications

The Co3O4 (110) single crystal surface has been characterized by low energy electron diffraction (LEED), Auger electron spectroscopy, and x-ray photoelectron spectroscopy (XPS). LEED analysis of the clean Co3O4 (110) spinel surface shows a well-ordered pattern with sharp diffraction features. The XPS spectra are consistent with stoichiometric Co3O4 as determined by the concentration ratio of oxygen to cobalt (CO /CCo) and spectral peak shape. In particular, the cobalt 2p XPS spectra are characteristic of the spinel structure with Co3+ occupying octahedral sites and Co2+ …

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Spectroscopic And Microscopic Investigation Of The Corrosion Of 316/316l Stainless Steel By Lead-Bismuth Eutectic (Lbe) At Elevated Temperatures: Importance Of Surface Preparation, Allen L. Johnson, Denise Parsons, Julia Manzerova, Dale L. Perry, Daniel Koury, Brian D. Hosterman, John Farley Jul 2004

Spectroscopic And Microscopic Investigation Of The Corrosion Of 316/316l Stainless Steel By Lead-Bismuth Eutectic (Lbe) At Elevated Temperatures: Importance Of Surface Preparation, Allen L. Johnson, Denise Parsons, Julia Manzerova, Dale L. Perry, Daniel Koury, Brian D. Hosterman, John Farley

Transmutation Sciences Materials (TRP)

The corrosion of steel by lead–bismuth eutectic (LBE) is an important issue in proposed nuclear transmutation schemes. Russian scientists at the IPPE exposed steel samples to oxygen-controlled LBE at temperatures up to 823 K and exposure times up to 3000 h. We have characterized these post-exposure steel samples and unexposed controls, using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX) and X-ray photoelectron spectroscopy (XPS). Previous researchers have investigated the corrosion by LBE of steel of varying composition. In the present work, we compared two samples having the same composition (standard nuclear grade 316/316L) but different surface preparation: a cold-rolled …

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Inside Unlv, Holly Ivy De Vore, Carol C. Harter, Stuart Mann Jul 2004

Inside Unlv, Holly Ivy De Vore, Carol C. Harter, Stuart Mann

Inside UNLV

No abstract provided.

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An Evening To Remember, Desmond H. Murray Jul 2004

An Evening To Remember, Desmond H. Murray

Faculty Publications

No abstract provided.

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Radical Initiated Polymerization In A Bifunctional Mixture Via Computer Simulation, Keri L. Diamond, Ras B. Pandey, Shelby F. Thames Jun 2004

Radical Initiated Polymerization In A Bifunctional Mixture Via Computer Simulation, Keri L. Diamond, Ras B. Pandey, Shelby F. Thames

Faculty Publications

Computer simulations are performed to study the polymerization behavior in a mixture of bifunctional groups such as olefins (A) and acrylates (B) in an effective solvent (a coarse description for vegetable oil derived macromonomers (VOMMs) in solution) on a cubic lattice. A set of interactions between these units and solvent (S) constituents and their relative concentrations (p(A), p(B), and p(S)) are considered. Samples are equilibrated with Metropolis algorithm to model the perceived behavior of VOMMs. The covalent bonding between monomeric units is then implemented via reaction pathways initiated by stochastic motion of free radicals (a very small fraction). The rate …

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Bridgehead-Methyl Analog Of Sc-53116 As A 5-Ht4 Agonist, Daniel Becker, Daniel L. Flynn, Clara I. Villamil Jun 2004

Bridgehead-Methyl Analog Of Sc-53116 As A 5-Ht4 Agonist, Daniel Becker, Daniel L. Flynn, Clara I. Villamil

Chemistry: Faculty Publications and Other Works

Pyrrolizidine benzamide (±)-2, the bridgehead-methyl analog of SC-53116, was prepared and evaluated for 5-HT4 agonism activity in the rat tunica muscularis (TMM) mucosae assay. Compound (±)-2 has an EC50 of 449 nM in the TMM assay, as compared to 23 nM for SC-53116, and 66 nM for the racemate of SC-53116.

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Emissions From Miombo Woodland And Dambo Grassland Savanna Fires, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirchstetter Jun 2004

Emissions From Miombo Woodland And Dambo Grassland Savanna Fires, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirchstetter

Chemistry and Physics Faculty Articles

Airborne measurements of trace gases and particles over and downwind of two prescribed savanna fires in Zambia are described. The measurements include profiles through the smoke plumes of condensation nucleus concentrations and normalized excess mixing ratios of particles and gases, emission factors for 42 trace gases and seven particulate species, and vertical profiles of ambient conditions. The fires were ignited in plots of miombo woodland savanna, the most prevalent savanna type in southern Africa, and dambo grassland savanna, an important enclave of miombo woodland ecosystems. Emission factors for the two fires are combined with measurements of fuel loading, combustion factors, …

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Characterization Of Epoxy Resin (Su-8) Film Using Thickness-Shear Mode (Tsm) Resonator Under Various Conditions, Jeanne Hossenlopp, Lizhong Jiang, Richard Cernosek, Fabien Josse Jun 2004

Characterization Of Epoxy Resin (Su-8) Film Using Thickness-Shear Mode (Tsm) Resonator Under Various Conditions, Jeanne Hossenlopp, Lizhong Jiang, Richard Cernosek, Fabien Josse

Chemistry Faculty Research and Publications

Characterization of an epoxy resin film, commonly known as SU-8, is presented using thickness shear mode (TSM) quartz resonator. The impedance-admittance characteristics of the equivalent circuit models of the unperturbed and coated resonators are analyzed to extract the storage modulus and loss modulus (G' and G''). Those parameters are needed to establish SU-8 film as an effective wave-guiding layer in the implementation of guided shear-horizontal surface acoustic wave (SH-SAW) sensor platforms. Both cured and uncured polymer films are studied at the fundamental and third harmonic frequencies of the TSM resonators. The storage modulus (G') and loss …

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Emissions From Miombo Woodland And Dambo Grassland Savanna Fires, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirschsetter Jun 2004

Emissions From Miombo Woodland And Dambo Grassland Savanna Fires, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirschsetter

Chemistry and Biochemistry Faculty Publications

[1] Airborne measurements of trace gases and particles over and downwind of two prescribed savanna fires in Zambia are described. The measurements include profiles through the smoke plumes of condensation nucleus concentrations and normalized excess mixing ratios of particles and gases, emission factors for 42 trace gases and seven particulate species, and vertical profiles of ambient conditions. The fires were ignited in plots of miombo woodland savanna, the most prevalent savanna type in southern Africa, and dambo grassland savanna, an important enclave of miombo woodland ecosystems. Emission factors for the two fires are combined with measurements of fuel loading, combustion …

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Hydrazine/Nitrogen Dioxide Fiber Optic Sensor, Alfred S. Andrawis, Josephine B. Santiago, Rebecca Young, Clayton J. Baum Jun 2004

Hydrazine/Nitrogen Dioxide Fiber Optic Sensor, Alfred S. Andrawis, Josephine B. Santiago, Rebecca Young, Clayton J. Baum

Chemistry and Chemical Engineering Faculty Publications

This paper outlines the development of a dual hydrazine/nitrogen dioxide (HZ/NO2) prototype fiber optic sensor utilizing an acid-base indicator that undergoes color changes depending on which gas is present. Bromothymol blue bromocresol green mixture (1/1) in hydrogel (1/1), produces a blue-green indicator for HZ and/or NO2. The sensor was tested several times over a period of eight weeks and the response was consistent and proved the feasibility of dual HZ/NO2 leak detection. Prototype sensor construction, the hardware, and the software of the electronic interrogator circuitry are briefly explained. The paper presents a summary of sensor response when exposed to 52 …

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Geminal Model Chemistry Ii. Perturbative Corrections, Vitaly A. Rassolov, Feng Xu, Sophya Garashchuk Jun 2004

Geminal Model Chemistry Ii. Perturbative Corrections, Vitaly A. Rassolov, Feng Xu, Sophya Garashchuk

Faculty Publications

We introduce and investigate a chemical model based on perturbative corrections to the product of singlet-type strongly orthogonal geminals wave function. Two specific points are addressed (i) Overall chemical accuracy of such a model with perturbative corrections at a leading order; (ii) Quality of strong orthogonality approximation of geminals in diverse chemical systems. We use the Epstein–Nesbet form of perturbation theory and show that its known shortcomings disappear when it is used with the reference Hamiltonian based on strongly orthogonal geminals. Application of this model to various chemical systems reveals that strongly orthogonal geminals are well suited for chemical models, …

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Evidence For Partial Quenching Of Orbital Angular Momentum Upon Complex Formation In The Infrared Spectrum Of Oh-Acetylene, Mark D. Marshall, James B. Davey, Margaret E. Greenslade, Marsha I. Lester Jun 2004

Evidence For Partial Quenching Of Orbital Angular Momentum Upon Complex Formation In The Infrared Spectrum Of Oh-Acetylene, Mark D. Marshall, James B. Davey, Margaret E. Greenslade, Marsha I. Lester

Chemistry

The entrance channel leading to the addition reaction between the hydroxyl radical and acetylene has been examined by spectroscopic characterization of the asymmetric CH stretching band of the π-hydrogen bonded OH-acetylene reactant complex. The infrared action spectrum observed at 3278.6 cm−1 (origin) consists of seven peaks of various intensities and widths, and is very different from those previously reported for closed-shell HF/HCl-acetylene complexes. The unusual spectrum arises from a partial quenching of the OH orbital angular momentum in the complex, which in turn is caused by a significant splitting of the OH monomer orbital degeneracy into 2A′ …

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Thickness Dependence Of Magneto-Transport In Cu-Co Granular Thin Films, Jian Qing Wang, Ngocnga Dao, Ham H. Kim, Scott L. Whittenburg Jun 2004

Thickness Dependence Of Magneto-Transport In Cu-Co Granular Thin Films, Jian Qing Wang, Ngocnga Dao, Ham H. Kim, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

This work explores the thickness dependence of magneto-transport properties in granular thin films with different thickness. These results are compared with silver-based film series studied earlier. It was observed that the thickness dependence of the GMReffect was sensitive to the surface chemistry of the films. The extraordinary Hall effect (EHE) in these films was measured and found to be different from the Ag-based system. In the Cu-based system, the EHE is a weak function of film thickness over the range studied. When the variation of the spontaneous magnetization is taken into account the effective EHE has a universal thickness dependence

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Metal Ion Imprinted Polymers For Biomolecular Recognition, Len A. Harris Jun 2004

Metal Ion Imprinted Polymers For Biomolecular Recognition, Len A. Harris

Masters Theses

Protein recognition by HPLC, based on histidine residues, was achieved by incorporating a copper chelating ligand covalently bonded to a polystyrene/divinyl benzene substrate, into column packing. The metal ion was bonded to the substrate in two ways: randomly, where the copper was bound to the ligand after the substrate polymerization and imprinted, where the copper was bound to the ligand before the substrate polymerization. The effect of this templating was measured by protein separation parameters of the resulting HPLC chromatographs. The hypothesis of this thesis is the imprinted substrate will have a higher copper content, and with coppers affinity toward …

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Characterization And Magnetic Properties Of Core/Shell Structured Fe/Au Nanoparticles, Sung-Jin Cho, Susan M. Kauzlarich, Justin Olamit, Kai Liu, Fernande Grandjean, Leïla Rebbouh, Gary J. Long Jun 2004

Characterization And Magnetic Properties Of Core/Shell Structured Fe/Au Nanoparticles, Sung-Jin Cho, Susan M. Kauzlarich, Justin Olamit, Kai Liu, Fernande Grandjean, Leïla Rebbouh, Gary J. Long

Chemistry Faculty Research & Creative Works

Au-coated Fe nanoparticles have been prepared by using a reverse micelle method through reduction of an aqueous solution. Characterizations have been carried out over time to probe the oxidation of Fe. Immediately after synthesis, the samples exhibit metallic conduction and a negative magnetoresistance, consistent with the presence of α-Fe. The temperature dependence of magnetization displays a maximum at a blocking temperature of around 150 K. After a period of 1 month, the samples exhibit insulating behavior, indicating the oxidation of the Fe core. Mössbauer spectroscopy indicates the presence of an α-Fe component and a broad distribution of local environments.

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A Magnetic And Mössbauer Spectral Study Of The Spin Reorientation In Ndfe₁₁Ti And Ndfe₁₁Th, Cristina Piquer, Fernande Grandjean, Olivier Isnard, Viorel Pop, Gary J. Long Jun 2004

A Magnetic And Mössbauer Spectral Study Of The Spin Reorientation In Ndfe₁₁Ti And Ndfe₁₁Th, Cristina Piquer, Fernande Grandjean, Olivier Isnard, Viorel Pop, Gary J. Long

Chemistry Faculty Research & Creative Works

The influence of hydrogenation on the spin reorientation in the presence of neodymium was investigated in NdFe11Ti and NdFe11TH. The magnetic properties of these compounds were determined by utilizing ac magnetic susceptibility, thermomagnetic, and iron-57 Mössbauer spectral analysis. It was found that the these compounds had two advantages as hard magnetic materials such as: a high iron content yielding high magnetization and a high Curie temperature. The investigation results show that these compounds undergo a spin-reorientation transition at ~185 K and at 100± K, from an axial magnetic phase at high temperature to a basal magnetic …

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Novel Chromium(Vi) Catalyzed Oxidation Of N-Alkylamides To Imides With Periodic Acid, Mark L. Trudell Jun 2004

Novel Chromium(Vi) Catalyzed Oxidation Of N-Alkylamides To Imides With Periodic Acid, Mark L. Trudell

Chemistry Faculty Publications

A novel and practical procedure for preparation of imides is described using chromium(VI) oxide to catalyze the oxidation of N-alkylamides with periodic acid in the presence of acetic anhydride in acetonitrile.

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Thickness Dependence Of Magneto-Transport In Cu-Co Granular Thin Films, Scott Whittenburg Jun 2004

Thickness Dependence Of Magneto-Transport In Cu-Co Granular Thin Films, Scott Whittenburg

Chemistry Faculty Publications

This work explores the thickness dependence of magneto-transport properties in Cu80Co20 granular thin films with different thickness. These results are compared with silver-based film series studied earlier. It was observed that the thickness dependence of the GMR effect was sensitive to the surface chemistry of the films. The extraordinary Hall effect (EHE) in these films was measured and found to be different from the Ag-based system. In the Cu-based system, the EHE is a weak function of film thickness over the range studied. When the variation of the spontaneous magnetization is taken into account the effective EHE has a universal …

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Evidence That Hsp90 Is Involved In The Altered Interactions Of Acanthamoeba Castellanii Variants With Bacteria, Ling Yan, Ronald Cerny, Jeffrey D. Cirillo Jun 2004

Evidence That Hsp90 Is Involved In The Altered Interactions Of Acanthamoeba Castellanii Variants With Bacteria, Ling Yan, Ronald Cerny, Jeffrey D. Cirillo

Ronald Cerny Publications

There are many similarities between the interactions of environmental protozoa with pathogenic bacterial species and those observed in mammalian macrophages. Since single-celled protozoa predate mammalian hosts, it is likely that interactions in environmental biofilms have selected for many of the bacterial virulence mechanisms responsible for human disease. In order to better understand bacterial-phagocyte interactions, we developed a selection for Acanthamoeba castellanii variants that are more resistant to killing by bacterial pathogens. We identified four amoebal clones that display decreased phagocytosis of bacteria but no difference in uptake of latex beads compared to wild-type amoebae. These amoebal variants display differences in …

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Nearest-Neighbor-Atom Core-Hole Transfer In Isolated Molecules, Renaud Guillemin, Oliver Hemmers, D. Rolles, S. W. Yu, A. Wolska, I. Tran, A. C. Hudson, J. Baker, Dennis W. Lindle Jun 2004

Nearest-Neighbor-Atom Core-Hole Transfer In Isolated Molecules, Renaud Guillemin, Oliver Hemmers, D. Rolles, S. W. Yu, A. Wolska, I. Tran, A. C. Hudson, J. Baker, Dennis W. Lindle

Environmental Studies Faculty Publications

A new phenomenon sensitive only to next-door-neighbor atoms in isolated molecules is demonstrated using angle-resolved photoemission of site-selective core electrons. Evidence for this interatomic core-to-core electron interaction is observable only by measuring nondipolar angular distributions of photoelectrons. In essence, the phenomenon acts as a very fine atomic-scale sensor of nearest-neighbor elemental identity.

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Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix: Quaterly Report April-June 2004, Spencer M. Steinberg Jun 2004

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix: Quaterly Report April-June 2004, Spencer M. Steinberg

Separations Campaign (TRP)

The recovery of iodine released during the processing of used nuclear fuel poses a significant challenge to the transmutation of radioactive iodine. This proposal will develop and examine the use of Fullerene Containing Carbon (FCC) compounds as potential sorbents for iodine release from the reprocessing of nuclear fuel. This work will also include the development of bench-scale testing capabilities at UNLV to allow the testing of the FCC material in a simulated process off-gas environment. This experimental capability will also be used to test other potential sorption materials and processes, such as natural organic matter (NOM) and other promising alternatives. …

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Polystyrene Magadiite Nanocomposites, Dongyan Wang, David D. Jiang, Jaclyn Pabst, Zhidong Han, Jianqi Wang, Charles A. Wilkie Jun 2004

Polystyrene Magadiite Nanocomposites, Dongyan Wang, David D. Jiang, Jaclyn Pabst, Zhidong Han, Jianqi Wang, Charles A. Wilkie

Chemistry Faculty Research and Publications

An organically modified magadiite has been prepared and used to make a mixed intercalated-exfoliated polystyrene nanocomposite by bulk polymerization. This system gives excellent improvement in mechanical properties, but the thermogravimetric analysis curves do not show any change in the onset of the degradation and the degradation pathway is not changed from that for virgin polystyrene, unlike the situation for an aluminosilicate clay, monlmorillonite. By cone calorimetry, the peak heat release rate is not changed, again unlike the results with the aluminosilicate. This suggests that not all clays exhibit the same behavior in nanocomposite formation.

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Kinetic Analysis Of The Thermal Degradation Of Polystyrene-Montmorillonite Nanocomposite, Serge Bourbigot, Jeffery W. Gilman Sr., Charles A. Wilkie Jun 2004

Kinetic Analysis Of The Thermal Degradation Of Polystyrene-Montmorillonite Nanocomposite, Serge Bourbigot, Jeffery W. Gilman Sr., Charles A. Wilkie

Chemistry Faculty Research and Publications

Nanocomposites exhibit a combination of unique properties, such as increased heat distortion temperature, reduced permeability, reduced flammability and improved mechanical properties. In this work, a polystyrene (PS) clay nanocomposite was prepared via bulk polymerization using a novel organically modified montmorillonite (MMT). The organic-modifier is the N,N-dimethyl-n-hexadecyl-(4-vinylbenzyl) ammonium chloride (VB16). The thermal stability of PS–VB16 compared to pure PS is examined in pyrolytic and thermo-oxidative conditions. It is then studied using a kinetic analysis. It is shown that the stability of PS is significantly increased in the presence of clay. The thermal behavior of PS and …

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Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Third Quarterly Report 03/01/2004-05/31/2004, Samir Moujaes, Yitung Chen May 2004

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Third Quarterly Report 03/01/2004-05/31/2004, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the TRP proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with only very sparse experimental data. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high …

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Evaluation Of Fluorapatite As A Waste-Form Material: Third Quarter Report, March 1- May 31, 2004, Dennis W. Lindle, Oliver Hemmers May 2004

Evaluation Of Fluorapatite As A Waste-Form Material: Third Quarter Report, March 1- May 31, 2004, Dennis W. Lindle, Oliver Hemmers

Separations Campaign (TRP)

Fluorapatite, fluorinated calcium phosphate, has been identified as a potential matrix for the entombment of the zirconium fluoride fission product waste stream from the proposed FLEX process. If the efficacy of fluorapatite-based waste-storage can be demonstrated, then new and potentially more-efficient options for handling and separating high-level wastes, based on fluoride-salt extraction, will become feasible. This proposal will develop a dual-path research project to develop a process to fabricate a synthetic fluorapatite waste form for the ZrF4, FP waste stream, characterize the waste form, examine its performance under environmental conditions, and correlate the behavior of the waste form …

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Two Kinds Of Polarons Observedin Polyaniline In Aqueous H2So4, Qin Zhou, Lin Zhuang, Jun-Tao Lu May 2004

Two Kinds Of Polarons Observedin Polyaniline In Aqueous H2So4, Qin Zhou, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

Simultaneous electrochemistry electron spin resonance (ESR) conductance measurements were carried out on electropolymerized polyaniline and ESR spectra were obtained with high signal/noise ratio. Spectral simulation revealed that in the early stage of polymerization, there were two kinds of polarons. According to the potential dependence of the ESR line width and the corresponding conductivitychange of the polymer, the two polarons are thought to be in ordered and disordered domains, respectively. With increasing doping level, the two polarons underwent similar transfer from Curie spin to Pauli spin and both polarons were charge carriers in the conducting polymer. This deduction was further supported …

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