Digital Commons Network^™

Scf-Mo Conformational Analysis Of Polycroconaine, T. E. Ezell, Jerry A. Darsey

Journal of the Arkansas Academy of Science

Abinitio calculations at the STO-3G basis set level using GAUSSIAN 92 were conducted on the monomer unit of polycroconaine, a conducting polymer with conductive properties similar to several metals, in order to determine the most probable conformation of the monomer. We also compared the energy difference between the highest occupied and lowest unoccupied molecular orbitals. Successive calculations were performed at dihedral angle intervals of 30° around the central bond of the monomer. Minimum energy was observed at 0° bond rotation, consistent with a theory that the polymer owes many of its conductive properties to a planar configuration in combination with …

Spectroscopic Temperature Measurements For A Direct Current Arcjet Diamond Chemical Vapor Deposition Reactor, Scott W. Reeve, Wayne A. Weimer

Journal of the Arkansas Academy of Science

The diamond thin filmcommercial market isprojected to exceed one billion dollars by the year 2000. Potential applications of diamond thin films range from cutting tools to electronics tomedical devices. The explosion ofinterest in this fieldresults from the extreme properties diamond possesses: itis the hardest material known toman and yet, has a coefficient of friction similar to Teflon;its ability to conduct heat is five times that of copper; and diamond is completely inert. However, despite the tremendous economic incentive, there are still several technological barriers preventing diamond filmscale-up to commercial production. Included among these are a fundamental understanding of the gas …

Photochemistry Of The Nitrite Ion, Laura J. Wilson '95

Honors Projects

Nitrogen containing compounds contribute to many environmental problems such as acid rain, air pollution, groundwater contamination, and smog formation. For example, when the atmosphere is heavily polluted with nitrites and aromatic hydrocarbons, nitrogen compounds can undergo photochemical reactions to produce harmful compounds that can adversely affect the environment. This project studied the photochemistry of the nitrite ion in aqueous basic solution. Both ·OH and NO· radicals are produced during photolysis, but the two radicals recombine in the presence of pure water causing no net reaction. Aromatic compounds present in the solution being photolyzed can act as scavengers reacting with either …

On-Road Remote Sensing Of Vehicle Emissions In Monterrey, N. L. Mexico, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

Neutron Diffraction Studies Of Erni₅₋ₓcoₓ (X=0.68, 1.68, 2.26) Alloys, Z. Zu, William B. Yelon, G. K. Marasinghe, William Joseph James

Physics Faculty Research & Creative Works

ErNi_5-xCo_x alloys were prepared by RF induction melting and analyzed using neutron powder diffraction. Rietveld analysis neutron diffraction data indicates the unit cell volume increases with Co content while the a and c lattice parameters show different dependencies on the composition. the Co atoms show higher affinity for the 3g sites than for the 2c sites. the Co sublattice tends to couple antiferromagnetically to the Er sublattice. the easy magnetization direction is along the c axis.

Neutron Investigations Of Novel Magnetic Phases, William B. Yelon

Physics Faculty Research & Creative Works

Recent years have seen a renewed search for Fe based permanent magnets, spurred by the discovery of Nd2Fe14B and interstitially modified rare-earth iron binaries. The insights derived from those compounds have suggested a number of routes to the development of such systems, including selective site substitution and combinations of site substitution and interstitial modification. Neutron diffraction is an essential component of this work, since it provides systematic information about the location of substitutional and interstitial atoms, and about the effects these changes have on the magnetic interactions in the systems of interest

A Diamond Thin Film Flow Sensor, Sacharia Albin, John C. Hagwood, John B. Cooper, David L. Gray, Scott D. Martinson, Michael A. Scott

Electrical & Computer Engineering Faculty Publications

We present the results of theoretical modeling and experimental testing of a diamond thin film sensor for flow studies. It is shown that the high thermal conductivity of a diamond film can enhance the frequency response of the flow sensor. One-dimensional heat diffusion equation was solved using the finite difference method for determining the frequency response. Two different sensor structures were analyzed: a Ni film on a quartz substrate (Ni/Q) and an intermediate layer of diamond film between the Ni film and quartz substrate (Ni/D/Q). The theoretical model predicts a frequency response for the Ni/D/Q sensor higher than that of …

Preparations Of Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group in an ethereal, polyethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydro-carbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme conditions.

Preparation Of Doped Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes, such as doped polycarbynes, prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group and, optionally, containing a doping agent, in an ethereal, poly ethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydrocarbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme con ditions.

Volatilization Of Contaminants From Wastewater, Shaoyan Wu

Theses

Emission of volatile organic compounds (VOCs) from many industrial wastewater treatment facilities are a major source of air pollution, and getting much attention from EPA. In order to determine "Best Available Control Technology" and "Lowest Achievable Emission Rate" for controlling emissions of VOCs from industrial wastewater, the accurate estimation of VOCs emission rate and realistic modeling of contaminant volatilization are required.

In this research, the volatilization of three compounds (Toluene, Xylene, and Aniline) were studied under varying aeration, stirring, and quiescent scenarios. The concentrations of contaminant were analyzed by HPLC. Experimental rate constants were obtained by using the first order …

Exposure Of A Food Crop To Trichloroethylene From A Contaminated Aquifer, Richard G. Baringer

Theses and Dissertations

This research developed a methodology for assessment of the exposure of a mature corn crop to trichloroethylene from a contaminated aquifer. The methodology was then applied to the case of Hill AFB to determine the ability of the methodology to provide information about a specific exposure. Current procedures sample for food contamination but do not attempt to predict exposure problems. A review of the potential exposure pathways from the aquifer to the crop was conducted. Based on this review, the exposures due to soil gas and irrigation were modeled. Empirical estimated were used to approximate the expected flux of soil …

Modeling Trihalomethane Formation Potential From Wastewater Chlorination, Carol A. Mccormick

Theses and Dissertations

The deletion of federally mandated fecal coliform limits has led many states to review and modify their wastewater disinfection requirements. One issue in analyzing wastewater disinfection is the discharge of potentially carcinogenic halogenated organics formed during the chlorination process. This research investigates the formation of one class of the halogenated organics, the trihalomethanes. The applicability of using drinking water trihalomethane formation models for use with wastewater effluent is examined. Three models are compared for predictive capability by using measured trihalomethane values from previous research data. The results show that a previously developed model is applicable for use based on assumptions …

Tucson Intersection Study Of Automobile Emissions, Amber K. Hodgson, Yi Zhang, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

Careers In Chemical Information And Science Librarianship, Philip Barnett

Publications and Research

The ceaseless growth of chemical information has created a need for chemical professionals who can organize and disseminate this vast knowledge. If you like to read, enjoy being in a library, or like to work with information on computers, you may want to consider a career in chemical information. While only a small fraction of chemists choose this nontraditional career, they have found fulfillment in many different roles. Chemical information scientists and librarians using the powerful computerized databases now available either provide chemists and other research scientists the information they need, or teach researchers and students how to use these …

Dissection Of An Antibody-Catalyzed Reaction, Jon D. Stewart, Joseph F. Krebs, Gary Siuzdak, Anthony J. Berdis, David B. Smithrud, Stephen J. Benkovic

Chemistry Faculty Publications

Antibody 43C9 accelerates the hydrolysis of a p-nitroanilide by a factor of 2.5 x 10(5) over the background rate in addition to catalyzing the hydrolysis of a series of aromatic esters. Since this represents one of the largest rate accelerations achieved with an antibody, we have undertaken a series of studies aimed at uncovering the catalytic mechanism of 43C9. The immunogen, a phosphonamidate, was designed to mimic the geometric and electronic characteristics of the tetrahedral intermediate that forms upon nucleophilic attack by hydroxide on the amide substrate. Further studies, however, revealed that the catalytic mechanism is more complex and involves …

36th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Program, abstracts, and information about the 36th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 31 - August 5, 1994.

Analysis Of The Potential For Plant Uptake Of Trichloroethylene And An Assessment Of The Relative Risk From Different Crop Types, Roy-Alan C. Agustin

Theses and Dissertations

This research expands our limited knowledge on the influence of plants on the fate and effects of trichloroethylene (TCE), providing a screening tool on which to base decisions regarding the need for actual sampling of plants. First, physicochemical properties of TCE--vapor pressure, Henry's Law constant, water solubility, octanol-water partition coefficient, molecular weight, and half-life--were screened against relationships reported in literature to evaluate TCE plant uptake potential. This screening approach indicated TCE may be transferred to plants via retention by root surfaces, root uptake and translocation, and foliar uptake. Next, the PLANTX model developed by Trapp and others was applied to …

Controlled Oxidation Studies Of Coal/Refuse Fuel Blends, Aiping Wu

Masters Theses & Specialist Projects

A study of the controlled combustion of blends of biomass materials and coals was conducted. Crushed limestone was added to the blends as an absorbent for sulfur oxides. The samples were combusted in quartz-fiber crucibles in a forced air furnace. Combustion at different times and temperatures were studied. The amount of carbon, hydrogen, and sulfur in the residues, as well as the amount of ash formed, were used as measures of combustion efficiency. The optimum temperature for combustion of most blends was found to be in the 700 - 800°C range. A study of methods for determining the amounts of …

Application Of A Modified Analytical Derivatization Method To The Determination Of Microbial Metabolites In Aquifer Systems, Jie Lu

Masters Theses

The geochemical evolution of Low Molecular Weight Fatty Acids (LMWFA's) in various ground water samples and aquifer solid samples from both contaminated and uncontaminated sites has been studied. An improved analytical method has been established for both qualitative and quantitative determination of LMWFA's. The low molecular weight (LMW) organic acids are metabolic intermediates of the oxidative biodegradation of hydrocarbon contaminants. The hydrocarbons are believed to be the electron donors in these redox reactions. Formic and acetic acids were found to be the major LMWFA's in these ground water samples and aquifer solid samples. Their concentrations increase as the redox condition …

The Application Of Stereolithography To The Creation Of Molecular Models Of Amiloride And Its Analogues, Thomas John Busanic

Theses

Stereolithography, a process by which a computer-guided Ultraviolet (UV) laser is applied onto a liquid monomer resin to form a solid polymer, was used to create solid models of amiloride and two of its analogues. The Cartesian coordinates used as input for the orientation of each atom in a molecule were calculated using ab initio molecular orbital theory. Since the structures of the molecules are calculated in this fashion, they represent a more accurate representation of the molecules than that provided by standard molecular modeling kits.

The original purpose of this work was to assist a blind chemist in appreciating …

The Pharmacodynamics And Toxicodynamics Of Inotropic Drugs In Calves With Natural And Artificial Hearts, Scott D. Everett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Inotropic support for the failing myocardium as the therapy for congestive heart failure (CHF) is intended to achieve an increase in cardiac output via positive responses in myocardial contractility and vasodilation. A novel approach to differentiate these two responses is the use of an animal with an implanted total artificial heart (TAH). Three inotropic drugs, dobutamine, enoximone, and pimobendan, were tested in eight animals with their natural heart intact and five animals implanted with a TAH. Baseline values of the TAH and natural heart (NH) were compared to determine their hemodynamic similarities. Each of the three drugs was given randomly …

Diamond Thin Film Sensors For Hypersonic Flow Studies, Bhaskar Kumar Bulusu

Electrical & Computer Engineering Theses & Dissertations

Conventional metal film sensors can measure flow instabilities of the order of 60 kHz. The turbulence fluctuations in the hypersonic regime are of the order of 200- 400 kHz. To measure these fluctuations, sensors with an enhanced frequency response are required. Therefore, it is required to identify the parameters to enhance the frequency response. These include parameters such as the temperature sensitivity, the resistivity, the thermal conductivity, the diffusivity, specific heat capacity and the geometric size and shape of the film and the substrate. A selection of materials was then carried out to maximize the frequency response. Diamond was identified …

Macrocyclic Antibiotics As A New Class Of Chiral Selectors For Liquid Chromatography, Christine Bagwill

Opportunities for Undergraduate Research Experience Program (OURE)

In the field of chromatographic separations, the need for new chiral stationary phases is always in demand. Many stationary phases already exist, some of the more popular being cyclodextrin or protein based phases. During this research, a new class of chiral selectors were discovered and evaluated for chiral recognition. Vancomycin, thiostrepton, and rifamycin B all belong to the macrocyclic antibiotic family. Not only can this new class of chiral selectors be used to resolve compounds that cannot be separated on any other column, but it is also more stable and has much greater capacity than protein based columns.

On-Road Remote Sensing Of Co And Hc Emissions In California, Donald H. Stedman, Gary A. Bishop, Stuart P. Beaton, James E. Peterson, Paul L. Guenther, Iain F. Mcvey, Yi Zhang

Fuel Efficiency Automobile Test Publications

No abstract provided.

Ab Initio Equilibrium Constants For H2o–H2o And H2o–Co2, Nancy Renyou Zhang, Donald D. Shillady

Chemistry Publications

Ab initio 6‐31G** electronic structure calculations have been used to determine the minimum energy geometries and vibrational frequencies of molecular clusters of water and carbon dioxide. Application of statistical thermodynamics leads to theoretical equilibrium constants for gas phase dimerization of water and the formation of an adduct of carbon dioxide with water.The low energy vibrations of the clusters lead to much larger contributions to the vibrational partitioning of the energy than do the fundamental vibrations of the monomeric species. A new ‘‘Harmonic‐Morse’’ formula is derived to estimate anharmonicity from optimized harmonic frequencies and two additional values on the potential surface …

Speciation Of Heteroatoms In Coal By Sulfur- And Nitrogen-Selective Techniquestrogen-Selective Techniques, Stephen R. Palmer, Michael A. Kruge, Edwin J. Hippo, John C. Crelling

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The peroxyacetic acid oxidation products from a series of coals of organic sulfur content 0.5-9.8 wt% were examined. The distributions of organic S and N compounds were determined by gas chromatography with sulfur-selective flame photometric and nitrogen-selective thermionic specific detection respectively. A selected sample was also examined in greater detail using low-voltage high-resolution mass spectrometry. The distribution of organic sulfur compounds in the oxidation products was remarkably similar for all the coals. The number of sulfur compounds detected was small compared with that of organic nitrogen compounds detected. This suggests that the sulfur chemistry of coal is considerably simpler than …

Initiation And Study Of Localized Corrosion By Scanning Electrochemical Microscopy, David O. Wipf

CAS Publications

This paper describes methods to study the initiation and formation of localized corrosion pits on stainless–steel and aluminum samples. These methods are based on the use of a scanned probe microscope, the scanning electrochemical microscope (SECM). The SECM is specifically designed for operation in electrolyte solution and so is uniquely suited for examination of corrosion processes. SECM imaging of a corrosion pit on stainless steel is presented. In addition, the initiation of single pits on aluminum and stainless steel by using the SECM tip to electrogenerate a local source of Cl^– is described.

The Chemistry Of Allergies, Henry Daley

Bridgewater Review

No abstract provided.

Oxidation Of Cyclohexene With Aqueous Potassium Peroxymonosulfate At Ph < 1.7, Wen-Qing Sun

Theses

Glycols are often used as starting materials for pharmaceuticals. They are currently manufactured by reacting alkenes with organic peroxy acids in organic solutions that contain chlorinated solvents. The aim of this research is to find ways to avoid the use of hazardous organic solvents in the manufacture of pharmaceuticals in order to prevent pollution. Our approach is to find alternative synthetic methods using water as solvent.

Based on literature information, it was decided to determine if the aqueous potassium peroxymonosulfate oxidation of water-immiscible cyclohexene at room temperature can be scaled up to become a new method to manufacture glycols. Acidic …

Reaction Of Titanocene Dichloride With Acetylenedicarboxylate, Tanya L. Hagler, Mark Draganjac, Paul M. Nave, J. Ed Bennett, Farooq Kahn, Robert Engelken, Gerard Williams, Chris Poole, Kwok Fai Yu

Journal of the Arkansas Academy of Science

The reaction of Cp2TiCl2 with either the mono- or dipotassium salt of acetylenedicarboxylic acid (ADC) gives high yields of an insoluble orange product. The insoluble compound shows potential semiconductor behavior, as evidenced by an apparent bandgap in the orange region of the visible spectrum. Under N2 ,the compound decomposes at 238° C, eventually losing approximately 46% total mass up to 1350° C. The exothermic decomposition in air, beginning at 235° C, results in the formation of titanium oxides.