Physical Sciences and Mathematics Commons^™

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 …

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, …

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 …

Wpływ Wybranych Parametrów Na Wielkość Emisji Zanieczyszczeń Powietrza Z Procesu Wysokotemperaturowego Spalania Odpadów Chloroorganicznych, Robert Oleniacz

Robert Oleniacz

In the paper preliminary analysis of the continuous measurements of the air pollutants emission and other

parameters of high-temperature process of chloroorganic waste incineration (liquid injection incinerator - Vicarb technology) are presented. In the analysis there was taken especially note of the parameters influencing the emissions, which could significantly vary in the incineration system (for example the amount of incinerated wastes) and pollutants like hydrogen chloride, nitrogen oxides and carbon monoxide. Basing the results of the analysis, it was affirmed that chlorine plays an inhibiting role on the formation of nitrogen oxides in the chloroorganic waste incineration system. On the …

Pictures From My Life With Polymer Science: Album 06, Otto Vogl

Otto Vogl

No abstract provided.

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.

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 …

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

Identification Of A Putative Caspase Protein In S.Commune, Emma Ester Bendaña Flores

Honors Theses

Caspases are the proteins responsible for apoptosis in cells. Others have recently identified a caspase in Saccharomyces cerevisiae, a unicellular fungus.2, 3, 4 Isolation of a caspase protein from Schizophyllum commune will allow for the examination of a caspase in a simple multicellular organism.4 The S.cerevisiae caspase sequence was used to search the genomes of several fungi and identify similar sequences. Regions with high sequence identity in the aligned sequences were used to design degenerate PCR primers. The sequence of the resultant PCR product was then used to prepare primers for 3'RACE and determine the 3'end of the sequence. Through …

Binding Studies Of 2-Acetylnaphthalene With Native And Methylated Cyclodextrins Using Fluorescence Spectroscopy : The Use Of Gas Chromatography/Mass Spectrophotometry To Analyze Organic Contaminants In Local Waters, Amy L. Payeur

Honors Theses

The main goal of this work: was to explore complexes formed between 2-acetylnaphthalene (2-AN) and unsubstituted α, β, and y-cyclodextrins as well as 2-An and methylated α, β and y-cyclodextrins. The substituted cyclodextrins used were trimethyl-α-cyclodextrin (TM-α-CD), trimethyl-β-cyclodextrin (TM-β-CD), trimethyl-y-cyclodextrin (TM-y-CD), and dimethyl-β-cyclodextrin (DM-β-CD). For the trimethylated cyclodextrins, all three of the -OH groups on the cyclodextrin ring are replaced by -OCH3 groups. The dimethylated cycloextrin on the other hand only has 18 of the 21 -OH groups replaces by -OCH3 groups. Binding constants were determined for complexes using fluorescence quenching experiments at varying temperatures. Thermodynamic parameters of complex formation …

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′ …

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.

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. …

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 …

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.

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 …

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 …

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.

Rotational Analysis Of Ftir Spectra From Cigarette Smoke.Pdf, Alan Ford, William A. Burns, Scott Reeve

Scott Reeve

No abstract provided.

Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The latest estimates of the FAO demonstrate the problems of the fight against hunger. These problems are manifested by the ever-increasing number of chronically undernourished people worldwide. Their numbers during the 1999-2001 period were estimated at about 840 million of which 798 million live in developing countries. Sub-Saharan Africa alone represented 198 million of those. In this part of Africa the prevalence of undernourishment ranges from 5-34%, causing growth retardation and insufficient weight gain among one third of the children under five years of age and resulting in a mortality of 5-15% among these children. Malnutrition resulting from undernourishment is …

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 …

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 …

Two Kinds Of Polaronsobservedin Polyanilinein Aqueous H_2so_4, 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 …

Studies Of Infrared Optical Properties Of Palladium Nanoparticles With Different Sizes And Dispersed States, Yan-Xia Jiang, Hong-Gang Liao, Wei Chen, Shi-Gang Ment Of Chemistry Xiamen University Sun, Xiamen Xiamen, China China

Journal of Electrochemistry

Pd nanoparticles with different sizes and dispersed states were prepared. Their infrared optical properties were studied with CO molecule probe. The infrared spectroscopic investigation revealed that Pd_(n)of 6.6 nm and Pd_n~(cube)of 100～150nmexhibit normal IR absorption. The center of IR bands are around 1 970 cm~(-1 )and 1 910cm~(-1). Pd_(n)is introduced into the surface of electrode, and is induced by interface electric fieldto form the aggregation of nanoparticles Pd_n~(ag). The Pd_n~(ag)has a different IR optical property from Pd_(n). The direction of IR absorption band of Pd_n~(ag)is changed from normal to abnormal at 1 970cm~(-1)with the increase of polarization time. The present …

Electrocatalytic And Lifetime Studies Of Commercial Catalystsin A Pemfc, Cheng Xuan

Journal of Electrochemistry

A particularly designed H-type cell was used to simulate the operating condition of a hydrogen-air proton exchange membrane fuel cell (PEMFC). The electrocatalytic activity, morphology, structure and lifetime of commercially available catalysts, carbon support platinum (Pt/C) and unsupported platinum-ruthenium (Pt-Ru), were preliminary studied by carrying out electrochemical measurements and by SEM, XRD techniques. The catalysts were simultaneously tested in the H-cell under operation, and also separately tested in a conventional electrochemical cell for comparison. It was found that the characteristic peaks of hydrogen adsorption/desorption on cyclic voltammograms shifted considerably to a more positive direction for Pt/C, while a more negative …

An Electrochemical Study Of Ddtc Adsorption Jamesonite, Run-Lan Yu

Journal of Electrochemistry

The interactions of jamesonite with diethyl dithiocarbamate (DDTC) were studied by AC impedance measurement and cyclic voltammetry. Several electrode processes under different potential conditions were observed. There mainly is the absorption of hydrophobic DDTC. PbD_2, S~0 etc on the surface of jamesonite mineral from -178 mV to 472 mV (vs. SHE) and the interfacial capacitance also is small. When the electrode potential is over 472 mV, the surface of jamesonite mineral is of hydrophilicity due to the fact that hydrophobic PbD_2,S~0 etc are oxidized into hydrophilic products such as Pb~(2+), SO_3~(2-) ,SO_4~(2-), PbSO_4. So it was deduced that the potential …

Direct Electron Transfer Of Redox Proteins And Enzymes Promoted By Carbon Nanotube, Chen-Xin Cai

Journal of Electrochemistry

The redox proteins (enzymes), such as hemoglobin (Hb), horseradish peroxidase (HRP) and glucose oxidase (GOx) were immobilized on the surface of the carbon nanotube modified with glassy carbon (CNT/GC) electrode, respectively. The experimental results showed that the redox proteins (enzymes) underwent effective and stable direct electron transfer reaction at the surface of CNT/GC electrode with a pair of nearly symmetrical redox peaks in phosphate buffer solution. The formal redox potential, E~(0'), is almost independent on the scan rates, the average value of E~(0') for Hb, HRP and GOx is -0.343±0.001, -0.319±0.002 and -0.456±0.001 V (vs.SCE,pH 6.9), respectively. The dependence of …

The Matching Study Of Electrodes In C/Ni(Oh)_2 Hybrid Capacitor, Yue-Feng Su

Journal of Electrochemistry

The energy storage mechanisms of electrochemical double-layer capacitor (EDLC) and C/Ni(OH)_2 hybrid capacitor had been studied. The results proved that,the difference between the capacity of EDLC and C/Ni(OH)_2 hybrid capacitor was detemined by the effectiveness usage of the activated carbon negative electrode, which is a criterion to estimate or design the theoretic capacity of the C/Ni(OH)_2 hybrid capacitor.The electrochemical availability of activated matter in Ni(OH)_2 electrode was introduced,and the quantity of the activated matter in Ni(OH)_2 electrode should be compatible with the capacity of carbon electrode .When the capacities of Ni(OH)_2 electrode and activated carbon electrode were matched well,the capacity …

Preparation, Characterization And Photoelectrochemical Activities Of Cu-Tio_2/Ito Films, Dong Shu

Journal of Electrochemistry

Cu-TiO_(2)/ITO films were prepared by direct photo-reduction deposition of Cu~(2+) on TiO_(2)/ITO films. The nanocomposite films were characterized by UV-vis diffuse reflectance spectra (DRS), XRD spectra, Scanning Electron Microscope (SEM) technology, and photovoltage measurement. The feasibility of improving the photocatalytic activity of TiO_(2) film by combining the modification of Cu nanoparticles with the application of anodic bias was investigated. The experimental results showed that the deposited Cu has an apparent enhancement effect with respect to suppressing the recombination between the photogenerated charge carriers and enhancing the photocatalytic oxidation of formic acid. The combination could promote the photocatalytic oxidation of formic …

Study Of Anti-Corrosion Property On Poly(An-Co-Oas)/Epoxy, Qing-Wu Wang, Geng-Chao Wang

Journal of Electrochemistry

polyaniline, polyanisidine and their copolymer poly(An-co-oAs) were synthesized via the solution chemical oxidative polymerization of aniline and anisidine in an acidic aqueous medium, and their properties and structure were characterized. The electrochemical method were applied to evaluate the corrosion behavior of tined iron uncoated or coated by polyaniline, poly(An-o-oAs), polyanisidine and poly(An-co-oAs)/epoxy blend in acid or saline aqueous solution. The result showed that with the increase of anisidine content, the solubility of polymers is improved apparently but their oxidation extent decreases accordingly. It is also founded that polyaniline, poly(An-co-oAs) and polyanisidine all have good anti-corrosion properties, and their anti-corrosion capacity …