Physical Sciences and Mathematics Commons^™

The Relationship Between Ionic Conductivity And The Structure Of The New Polymer Electrolytes, Hongze Liang, Yongxiang Song, Liming Ding, Yuchen Qi, Lixia Li, Xiabin Jing, Fusong Wang

Journal of Electrochemistry

Ionic conductivity of polymer-eutectic composed of lithium perchlorate and lithium nitrate has been studied. The effects of eutectic and polymers upon the conductivities have been discussed.The lonic conductivity depends on the eutectic properties as well as the treatment method of samples.

Improvement Of The Anti-Interference Characteristics Of God Electrode By Using The Powder Microelectrode Technique, Chen Jian, Chuansin Cha

Journal of Electrochemistry

The electrochemical behavior of ascorbic acid(AA),uric acid(UA),L-cystein(L-Cys)and acetaminophen(APAP),i.e.the main interference to the GOD electrode,were studied at the Pt,GC and powder microelectrode. Experimental results indicated that,due to the electrochemical activity of these interference,it is difficult to eliminate their interference effects by manipulation of electrede materials or working potential of the GOD electrode. However,it was found that the limiting curtents at the KB electrode are mainly controlled by mass transfer in liquid phase,so it is only related to the geometer size of the electrode,not its rcal surface area. Therefore,it is possible to enhance significantly the signal/noise ratio of the GOD electrode by …

A Study On Electrochemical Oxidation Of Reduced Nicotinamide Coenzyme Nadh In Organic Media, Fangzu Yang, Wuhuihuang Wuhuihuang, Xushukai Xushukai, Zhoushsomin Zhoushsomin

Journal of Electrochemistry

The behaviour of electrochemical oxidation of the reduced nicotinamide coenzyme NADH on glassy carbon was studied and some kinetic parameters were measured by means of voltammometry in the N-dimethylformamide(DMF)and 1,4-dioxane media respectively. The eletrochemical oxidation of NADH shows completely irriversable both in the two solvents,and the diagnostic experiments support that the process involves a fast chemical step.The oxidation rate and the diffusion coefficient of N ADH in DMP are smaller than those in 1,4-dioxane,but the response current is more stable in DMF. The experimental results are discussed by solvent effects.

Study On The Growth Process Of Lead Dioxide On Lead-Antimony Electrodes By Impedance Tracing Method, Guolin Wei, Hongxin Yang, Jiarong Wang

Journal of Electrochemistry

The growth process of PbO2 formed by the oxidation of PbSO4 in the anodic film on lead-(1,3,5,7)wt%antimony electrodes was investigated with impedance tracing method of single frequency and the current-time transient method. The influence of antimony on this process was studied.The simulation curves obtained for capacity-time transients fit the experimental results very well.It has been shown that the mentioned growth process is a two-dimentional instantaneous nucleation and growth process,Antimony will inhibit the growth of PbO2 nucleus but enhance its nucleation.

Kinetics And Jamming Coverage In A Random Sequential Adsorption Of Polymer Chains, Jian-Sheng Wang, Ras B. Pandey

Faculty Publications

No abstract provided.

A Stable Β-Silyl Carbocation, Joseph B. Lambert, Yan Zhao

Yan Zhao

The β effect of silicon, whereby a carbon-silicon bond substantially stabilizes an adjacent carbocation (Si-C-C+), has been widely studied mechanistically and exploited synthetically. 1-25 The phenomenon normally is invoked in reactive intermediates. Attempts to prepare stable Me3SiCH2CPh2 + under standard magic acid conditions led to loss of trimethylsilyl and observation only of CH3CPh2 +.11 A 2-(trimethylsilyl)allyl cation stable only at -100 °C did not comprise a β-effect system, as the silyl group destabilized the ion and the C-Si bond was orthogonal to the carbocation ð orbitals.21 Siehl and Kaufmann23 prepared 1-arylvinyl cations stabilized by β-silyl groups in magic acid at …

49. J. Johan Lindberg, Otto Vogl, Franciska Sundholm

Otto Vogl

No abstract provided.

Comparison And Modeling Study Of Vancomycin, Ristocetin A, And Teicoplanin For Ce Enantioseparations, Mary P. Gasper, Alain Berthod, Usha B. Nair, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The structurally related glycopeptide antibiotics vancomycin, ristocetin A, and teicoplanin can all be used as chiral selectors in capillary electrophoresis (CE). Both experimental and modeling studies were done to elucidate their similarities and differences. There are identifiable morphological differences in the aglycon macrocyclic portions of these three compounds. In addition, there are other structural distinctions that can affect their CE enantioselectivity, migration times, and efficiency. Teicoplanin is the most distinct of the three and is the only one that is surface active. Its aggregational properties appear to affect its enantioselectivity among other things. The similar but not identical structures of …

The Role Of Written And Verbal Expression In Improving Communication Skills For Students In An Undergraduate Chemistry Program, Brian P. Coppola, Douglas S. Daniels

Chemistry Faculty Publications

Proofreading, editing, and critique, the customary assessment tools scientists use to evaluate professional journal articles, grant applications, and any other writing, can be applied equally well in introductory science instruction. Such feedback is, in fact, crucial to growth and development. When learning anything new, students and faculty alike rely heavily on sources other than themselves (‘external editors’) to assess their understanding as they develop self-assessment skills (or ‘internal editors’). Although they rarely describe it in these terms, faculty nonetheless assume that students have developed and refined their internal skills by the time they take examinations and write term papers. Unfortunately, …

Synthesis And Characterisation Of New Dimolybdenum (Ii,Ii) Dicarboxylates And Their Use As Polymerization Catalysts, Elizabeth Whelan

Masters

The purpose of this work was to prepare a series of new dimolybdenum(II,II) dicarboxylate complexes, to characterize the complexes and to investigate their use as potential catalysts for the ring-opening metathesis polymerization (ROMP) of the bicyclic monomer norbornene.

Reactions Of Chlorine And Some Of Its Oxygen Derivatives With Phenol, Lizhuo Zhang

Masters Theses

Chlorine is widely used in industry. It is also the most commonly used disinfectant in water treatment plants. Since the amount of chlorine used is increasing each year, environmental and health concerns arise due to its reactivity with various of organic compounds. Many chlorinated organic compounds are toxic and as a result other non-chlorinating compounds, such as chlorine dioxide, might be potential substitutes in the future, especially in water treatment plants.

Previous studies have indicated that chlorinated organic compounds are not formed when chlorine dioxide is used as a disinfectant. Furthermore no reaction occurs between chlorite and phenol in the …

A Hplc Method To Assay Mycotoxins - Fumonisin, Ochratoxin And Zearalenone, Nalini Sadagopan

Masters Theses

A HPLC method to quantitate the mycotoxins Fumonisin B1 (FB1), Ochratoxin A(OA), and Zearalenone (ZON) was developed and validated. Mycotoxins are secondary metabolites of fungi like Fusarium, Asperigillus and Penicillium that contaminate crops. They have a wide array of chemical structures which facilitate their analytical detection.

The analytical method consists of reverse phase chromatography and fluorescence detection. Sample cleanup was performed using SAX and C18 cartridges prior to analysis on the HPLC.

The method developed for FB1 is unique in that it is more sensitive, accurate, and reproducible than the existing methods. Automation is one of the salient features that …

Neutron Diffraction Structural Study Of Ce₂Fe₁₇₋ₓgaₓ, H. Luo, Z. Hu, William B. Yelon, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, D. P. Middleton, K. H. J. Buschow

Physics Faculty Research & Creative Works

Six samples of Ce₂Fe_17-xGa_x with nominal Ga content x equal to 0, 0.3, 0.5, 0.7, 1.0, 2.0 have been studied by powder neutron diffraction at room temperature. Both crystalline and magnetic refinements have been carried out. All six samples adopt the Th₂Zn₁₇-type rhombohedral structure. The only additional phase found is α-iron. Gallium atoms are found to have high affinity for the iron 18h site, and are absent from the 9d and 18f sites. The Ga substitution for Fe leads to an expansion of both the a and c axes. The Curie …

A Study Of The Effect Of The Extraction Procedure In The Analysis Of Organic Compounds Adsorbed On Coal Ash, Shobha Purushothama

Masters Theses & Specialist Projects

The organic compounds found adsorbed on coal fly ash have been a cause for concern since the early days of the industrial revolution. A vast majority of the compounds reported as being adsorbed on the ash are polyaromatic hydrocarbons (PAHs). This study represents an attempt to evaluate the parameters involved in the extraction, detection and quantitation of these organic compounds. Though no definite conclusions could be reached as to the most efficient method of extraction, interesting results were obtained with regarding the choice of the solvent and the temperature programming on the GC/MS used for analysis. The solvent of choice …

Degradation Product Analysis Of Bismaleimide Composite, Wendy Zhong

Masters Theses & Specialist Projects

This study evaluates the thermal and oxidative stabilities of a bismaleimide (BMI) polymer composite reinforced with an intermediate modulus graphite fiber, Cytec®5260/IM7. The composite is aged in helium, nitrogen, and air at elevated temperatures up to 600°C. Its weight change is followed thermogravimetrically for stability assessment. The effect of aging gas environment is also studied. The use of on-line gas cell fourier transform IR spectrometer (FTIR) and mass spectrometer (MS) allows for the identification of decomposition products by evolved gas analysis. This combination of thermogravimetric analysis (TGA) and evolved gas analysis by FTIR and MS yields complementary information regarding pyrolysis …

Directed Ortho-Metalation Of The Three Methyl Anisoles In Various Media, Carl Friesen

Masters Theses & Specialist Projects

Directed ortho-metalation (DoM) is a very useful alternative to electrophillic aromatic substitution (EAS) for the synthesis of substituted aromatic compounds. DoM is highly regiospecific providing metalation chiefly in the ortho-position. However, lateral (a-) metalation of an alkyl side-chain and ortho-metalation of a second ortho-position can compete. Investigation of the three methylanisoles was therefore undertaken to determine the interplay between these factors and to discover metalation conditions to achieve selectivity. This goal was uniquely achieved for p-methylanisole where conditions were discovered which allowed > 85% ortho-metalation as determined by GC analysis with virturally no competing lateral metalation. Three derivitives of this ortho-lithio …

Reducibility, Thermal And Mass Scaling In Angular Correlations From Multifragmentation Reactions, L. Phair, L. G. Moretto, G. J. Wozniak, R. T. De Souza, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu

Faculty Publications

The azimuthal angular correlations of light charged particles and light intermediate mass fragments emitted from the reaction 36Ar+197Au at E/A=50MeV are found to be reducible to the angular distributions of individual fragments. Thermal scaling is also observed in the coefficients of the angular correlations. Furthermore, the observed scaling with fragment mass seems to imply secondary emission from relatively small ( A≈15–30) primary fragments.

Hydrocarbon Speciation Studies In Ancient Sediments By High Temperature Supercritical Carbon Dioxide Extraction, Doraida Diaz

FIU Electronic Theses and Dissertations

Results on the application of high-temperature supercritical carbon dioxide extraction (HT-SFE) to the study of hydrocarbon (HC) speciation in geological samples are presented. Ancient sediments were treated by stepwise extractions, and by using a fresh sample each time. SFE temperatures ranged between 50 and 350°C. Individual analytes showed to be speciated in different ways throughout the solid matrix because different fractions are extracted under different energy conditions. Aromatic HCs appear to have a stronger association with the matrix than the aliphatics due to their higher polarity and molecular planarity. No evidence of geosynthesis of alkylaromatics during HT-SFE was obtained. Tri- …

38th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 38th 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 21-26, 1996.

Model Calculations Of Langmuir Monolayers: Pressure Effects On Tilting Behavior Of Idealized Amphiphiles, D.R. Swanson, Robert J. Hardy, Craig J. Eckhardt

Craig J. Eckhardt Publications

Model amphiphiles consisting of lines of Lennard-Jones (LJ) centers are investigated to determine the effect of pressure and molecular geometry on ground-state tilting behavior. Both the amphiphile length and the intramolecular distance between LJ centers is varied. The results give guidelines for understanding and controlling tilting behavior in monolayer films.

50. Henri Benoît, Otto Vogl, Jeanne-Dominique Gass

Otto Vogl

No abstract provided.

Automation And Analysis Of Thermometric Titrations, Russel P. Linneman Ii

Honors Theses

Over the past three years, I have been involved in the development and testing of an automated thermometric titration system for chemical research. There were three major phases in this process. The first phase consisted of modernizing the equipment and software. The second phase consisted of testing the software and equipment with a known chemical system. The third phase consisted of original research.

Structure, Dynamics, And Phase Transitions In The Fullerene Derivatives C_{60}O And C_{61}H_{2}, C. Meingast, G. Roth, L. Pintschovius, R. H. Michel, C. Stoermer, M. M. Kappes, Paul A. Heiney, Laurent Brard, Robert M. Strongin, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

The effect of perturbing the icosohedral symmetry of C₆₀ by the addition of the side groups -O and -CH₂ upon orientational order-disorder and glass transitions in solid C₆₀ has been studied by a combination of high-resolution capacitance dilatometry and single-crystal x-ray and powder inelastic neutron scattering. Both fullerene derivatives C₆₀O (epoxide) and C₆₁H₂ (6,5-annulene) are shown to undergo a sequence of transitions similar to that found in pure C₆₀, i.e., a first-order orientational ordering transition just below room temperature followed by an orientational glass transition at lower temperatures. Although the …

Contrast-Enhanced Magnetic Resonance Imaging Confirmation Of An Anterior Protein Pathway In Normal Rabbit Eyes, Nancy H. Kolodny, Thomas F. Freddo, Barbara A. Lawrence, Cristina Suarez, Stephen P. Bartels

Chemistry: Faculty Publications

Purpose: Contrast-enhanced proton magnetic resonance imaging ( 1H MRI) has been used as a quantitative, noninvasive method to corroborate a pathway for the diffusion of plasma-derived protein into the aqueous humor in the normal rabbit eye. Methods. T1-weighted magnetic resonance images were produced over 1- to 3-hour periods after the intravenous injection of gadolinium diethylenetriamine-pentaacetic acid. Results. Analysis of the images yielded the time dependence of signal enhancements within the areas of interest. The ciliary body showed an immediate sharp increase, followed by a gradual decrease in signal enhancement with time. Although a gradual increase in signal enhancement was found …

Rare And Endangered Plants At Gateway National Recreation Area: A Case For Protection Of Urban Natural Areas, Richard Stalter, Michael D. Byer, John T. Tanacredi Ph.D.

Faculty Works: CERCOM (1977-2016)

The diversity of native plant species in urban environments is usually overlooked when biodiversity levels are considered. Inventories of native plants reveal many to be rare species surviving the harsh conditions encountered in urban ecosystems. Knowledge of their existence and an inventory of their distribution will assist in maintaining these populations. Protection strategies for rare plant species are outlined for urban National Parks.

Reactions Of Aqueous Chlorine With Alanylphenylalanine In Model Solutions And In A Wastewater, Thomas C. Fox

Chemistry & Biochemistry Theses & Dissertations

Model solutions of the dipeptide alanylphenylalanine were chlorinated to four different chlorine-to-amino nitrogen (Cl₂/Ala-Phe) mole ratios and analyzed by high performance liquid chromatography. At mole ratios ≤ 1, N-chloroalanylphenylalanine was the only major product. As the Cl₂/Ala-Phe mole ratio was increased to ≥ 2, N,N-dichloroalanylphenylalanine was the only major product. In model solutions (pH 7.0) the dichlorinated dipeptide decomposed (t_1/2= 4.1 hr) to form a stable N-chloroketimine, which has a half-life of 125 hours. This N-chloroketimine then decomposed to form phenylalanine.

To follow these reactions in a wastewater, alanyl-p-[ …

Comparison Of Positive Screening And Confimatory Results From Federally Mandated Drug Testing Of Urine, Mary M. Stuck

Community & Environmental Health Theses & Dissertations

The purpose of this study was to analyze the accuracy of FDA approved immunoassays for the detection of drug positive urine samples.

Federal civilian employees are tested under the strict protocol of the Department of Health and Human Services mandatory guidelines for federal workplace drug testing programs. The guidelines provide for a two instrument testing protocol for the analysis of urine samples. The first is an FDA approved immunoassay. Samples which test positive on this screening immunoassay are then submitted for confirmatory testing with the "gold standard" gas chromatography/mass spectrometry.

Agency monthly drug testing summaries, required under the DHHS guidelines …

Concentrations, Complexation And Speciation Of Total Dissolved Zinc In The Chesapeake Bay, Charles William Henry Iii

Chemistry & Biochemistry Theses & Dissertations

This is the first research to examine the horizontal, vertical, and temporal variability of total dissolved zinc, organic complexation of zinc, and zinc speciation in the Chesapeake Bay. Filtered (0.45μm) surface and bottom water samples were taken along the salinity gradient of the Chesapeake Bay in October 1993, March 1995, July 1995, and October 1995. Analysis by Differential Pulse Anodic Stripping Voltammetry (DP ASV) indicated that total dissolved zinc concentrations in the Bay ranged from 2.9 ± 0.7nM to 38.8 ± 2nM. Total zinc was highest at the northern end of the Bay (low salinity), approximately 10 times lower at …

A High School-Collegiate Outreach Program In Chemistry And Biology Delivering Modern Technology In A Mobile Van, Chris Craney, April Mazzeo, Kaye Lord

Chris L. Craney

The "Teachers plus Occidental equals Partnership in Science" van program in Los Angeles CA was launched in June 1992. The program's goal is to improve high school biology and chemistry students' laboratory instruction by enhancing their teachers' knowledge and classroom application of modern instruments, techniques and experiments.

Two-Dimensional 1H Nmr Studies On Octahedral Nickel(Ii) Complexes, Richard C. Holz, Evgenij A. Evdokimov, Feben T. Gobena

Chemistry Faculty Research and Publications

The dinucleating ligand ethylene glycol−bis(β-aminoethyl ether) N,N,N‘,N‘-tetrakis[(2-(1-ethylbenzimidazoyl)] (EGTB-Et; 1) was used to synthesize the dinuclear Ni(II) tetraacetonitrile complex cation [Ni₂(EGTB-Et)(CH₃CN)₄]²⁺ (2):  triclinic space group P1̄ (a = 12.273(5) Å, b = 12.358(7) Å, c = 12.561(6) Å, α = 90.43(4)°, β = 110.26(3)°, γ = 99.21 (4)°, and Z = 1). The structure shows two identical octahedral Ni(II) centers each bound to two benzimidazole ring nitrogen atoms, one amine nitrogen atom, an ether oxygen atom, and two acetonitrile nitrogen atoms. The …