Physical Sciences and Mathematics Commons^™

Investigation Of The Corrosion Of Steel By Lead-Bismuth Eutectic (Lbe) Using Scanning Electron Microscopy And X-Ray Photoelectron Spectroscopy, Daniel Koury

UNLV Theses, Dissertations, Professional Papers, and Capstones

Lead Bismuth Eutectic (LBE) has been proposed for use in programs for accelerator transmutation of waste. LBE is the leading candidate material as a spallation target and an option for the sub-critical blanket coolant. The corrosion of 316 and 316L stainless steels by LBE has been studied using UNLV's facilities for Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). We have compared exposed and unexposed samples and studied the differences. Some amount of surface contamination is present on the samples and has been removed by ionbeam etching. The unexposed samples reveal typical stainless steel characteristics: a chromium oxide passivation …

Exciplex Tuning And Optical Memory Studies For Dicyanoargentate(1) And Dicyanoaurate(1) Ions Doped In Potassium Chloride Crystals Extension To Mixed Metal Gold And Silver Systems, Samanthika Ruvinie Hettiarachchi

Electronic Theses and Dissertations

Exciplex tuning and optical memory behavior of [Ag(CN)₂^-] and [Au(CN)₂^-] ions doped in KCl host crystals, pure KAg(CN)₂, and pure KAU(CN)₂ have been studied. Additionally, d¹⁰-d¹⁰ (KAu(CN)₂-KAg(CN))₂) and d¹⁰-d⁸ (KAu(CN)₂, KAg(CN)₂- K₂Pt(CN)₄) mixed metal systems have been synthesized and characterized. Several ultraviolet and visible emission bands are observed for [Ag(CN))₂^-] and [Au(CN)₂^-] ions doped in KC1 host crystals. Each emission band becomes dominant at a characteristic excitation …

Mechanistic Studies On The Antagonistic Effect Of Chromium On Bpde Mutant Frequency In Human Fibroblasts, Felicia Codrea

Masters Theses

The purpose of this study was to investigate the possible mechanisms involved in the decrease in mutant frequency when cells are treated with two different types of carcinogens: chromium (VI) in combination with benzo(a)pyrene diol epoxide (BPDE). Three of our working hypotheses are: Cr alone or Cr and BPDE synergistically activate detoxifying enzyme glutathione-S-transferase (GST), Cr alone or Cr and BPDE act synergistically to inhibit cell cycle at the G₁/S boundary thus allowing more time for DNA repair, and Cr alone or Cr and BPDE synergistically activate DNA repair systems which result in more efficient repair of DNA …

Alignment, Mechanical And Thermo-Physical Characterization Of Nanofiber-Reinforced Polyethylene, Veronica M. Diaz-Serrato

Theses and Dissertations - UTB/UTPA

Alignment of vapor grown carbon nano-reinforced polyethylene composites was performed using conventional extrusion processing methods. The alignment of the nanofibers within polyethylene, PE; the matrix, produced a material with anisotropic behavior. Mechanical and thermo-physical properties of the nanocomposite were studied. Enhancements in mechanical properties were investigated for pure PE, misaligned, and aligned specimens for stress versus strain, maximum load, and Young's modulus as high as 185, 273, and 80%, respectively. In fact, toughness was considerably high for the 10 rpm specimen when compared to other samples of different windup speeds. Thermo-physical studies were performed using differential scanning calorimetry (DSC) and …

A Microfabricated Microconcentrator For Sensors And Chromatography, Minhee Kim

Dissertations

The detection and quantitative measurement of trace components is a challenging task. The key component in such an instrument is the concentration step where the analytes are accumulated before the analysis. In this research, simple and inexpensive processes for the microfabrication of microconcentrator that can be used with sensors and as an injector in GC were developed. Analytes are selectively concentrated in the microconcentrator. Rapid electrical heating of the microconcentrator releases the adsorbed species as a 66 concentration pulse", which serves as an injection for the detection system. The relatively small size of the microconcentrator allows it to be heated …

Catalytic Reduction Of Nitric Oxide By Solid Carbonaceous Material Under Lean Condition, Shan Xiao

Dissertations

The reactions of O₂, NO_x and soot from Diesel exhaust over Cu containing catalysts can significantly reduce soot and NO_x emissions while producing N₂ and CO₂. The author has evaluated the performance of Cu ion exchanged ZSM-5 and Cu adsorbed on Granulated Activated Carbon (Cu-GAC) using GAC as a surrogate for soot in a packed bed reactor. CO, formed primarily by the oxidation of GAC with O₂, appears to be a stable intermediate in the reduction of NO. With experimental parameters chosen to simulate Diesel exhaust conditions, Cu-GAC is much more …

Polymer-Supported 14-Crown-4 And Bifunctional Resins For Selective Metal Ion Complexation: Synthesis And Characterization, Christy L. Stine

Doctoral Dissertations

Polymer-supported 14-crown-4 and bifunctional resins containing amine and phosphonate ester ligands were synthesized and characterized. Complexation studies were performed to evaluate the metal ion selectivity of the resins.

The immobilization of 14-crown-4 onto crosslinked polymer supports for the complexation of Li(l) from aqueous solutions was studied. M any methods were attempted, but etherification of the hydroxymethyl form of 14-crown-4 was found to be the most successful. The polymers examined were poly(vinylbenzyl chloride), poly(vinylbenzyl chloride)-co-acrylamide and poly(glycidyl methacrylate). The amount of Li(l) complexed by the crown ether supported polymers was affected by the polarity (i.e., hydrophilicity) of the polymer matrix. The …

The Use Of Native And Modified Cyclodextrins For Method Development In Capillary Electrophoresis And Chemical Sensor Applications, Mustafa Culha

Doctoral Dissertations

The development and design of novel methods and materials for separation and sensing systems have critical importance for the analysis of complex mixtures. In these systems, molecular recognition is the key element for desired selectivity and it can only be achieved using rationally designed, chemically selective reagents. Cyclodextrins (CDs) are a group of macro-cyclic molecules that can recognize certain analytes depending on their shape and size. In this work, the primary goal was the design and development of CD-based separation and sensing systems. Native and derivatized CDs were utilized to develop methods for separation of a complex mixture containing six …

The Biophysical Basis Of Triplet Repeat Dna Expansion In Genetic Disease, Anthony M. Paiva

Seton Hall University Dissertations and Theses (ETDs)

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Simulation Of Structure, Dynamics And Electron Diffraction Patterns Of Heterogeneous Clusters Armn2N, W. H. Jinasena

Electronic Theses and Dissertations

The nitrogen-argon system provides a useful paradigm for studying segregation and mixing behavior in heterogeneous clusters. Using three realistic pair potentials corresponding to argon-argon, nitrogen-nitrogen and argon-nitrogen interactions, the structures and thermodynamics of Ar_m(N₂)_n, clusters are investigated. Comparison of these results to previous simulation results on neat argon and nitrogen clusters is made. The initial focus of the study is the series of thirteen particle clusters of Ar_m(N₂)_13-m (0 ≤ m ≤ 13); molecular dynamics in the microcanonical ensemble is the principle simulation tool. The icosahedral nitrogen-argon clusters …

Stabilization Of Rutile-Related Thin Film On Tio2 Substrates, Youngnam Cho

Electronic Theses and Dissertations

Conducting metal oxide thin films are of broad interest because they have a wide variety of magnetic and electronic properties. Materials exist that range from superconducting to insulating, are ferromagnetic and are ferroelectric. These properties make thin conducting oxide films attractive for many industrial applications. A class of metal oxides exists that adapt the rutile crystal structure; the structure of the mineral rutile, TiO₂. These metal oxides have the general formula MO₂ where M is a metal cation of valence +4. Metal oxides crystallizing in the rutile structure also display a wide variety of physical properties. The …

Metal Ion Separation Mediated By Organized Molecular Assemblies, Hong Cao

Masters Theses

We have investigated the separation of Co(II), Ni(II), Cu(II) and Zn(II) by the ligands 8-hydroxyquinoline- 5-sulfonic acid and 7-iodo-8-hydroxy-quinoline- 5-sulfonic acid in the presence of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant octyltrimethylammonium bromide (OTAB) . Baseline separations have been achieved by HPLC employing an octadecylsilanized silica (ODS) column. The underlying mechanisms of separation have been determined.

The significant new results of our studies are: (1) separation is not possible without the presence of surfactants and hence organized assemblies; (2) separations can be achieved under submicellar concentrations; (3) the separations are not driven by micelles; and …

Studies Towards Anti-Bredt Ring Systems Of Natural Products, Ulf Peters

Masters Theses

Different ways for the synthesis of anti-Bredt ring systems of natural products have been explored.

An intended Favorskii rearrangement-divinylcyclopropane rearrangement to lead to the bicyclo[4.3.1] decadiene ring system was not accomplished. An envisioned tandem cyclopropanation-divinycyclopropane rearrangement of 2,3-divinyhex-2-enol did not furnish the desired bicyclo[4.4.1]undecadiene system, either, because cyclopropane occurred on the exocyclic double bond.

In the course of cyclopropanation studies on various cyclohexenols, an α-silyl-α-diazoethyl acetate was employed as tether. It could be removed by protodesilylation or oxidative cleavage to give a 1-(carboxylic ester)-cyclopropane or a 1-(carboxylic easter)-1-hydroxy cyclopropane derivative, respectively. Cyclopropanation general occurred on the less substituted more …

Weinreb Amides : Novel Titanium Enolate Reagents, Andrew J. Leyhane

Honors Theses

The amides of N-methoxy-N-methylamine or "Weinreb amide" have earned an important role in synthetic chemistry as both a protective group and as synthetic intermediates. We have discovered that the Weinreb amide of acetic acid, N-methoxy-N-methylacetamide adds to aldehydes to afford classic aldol products in good to excellent yields. The scope of this novel aldol reaction will be discussed.

Inclusion Chemistry Of Neutral Nonlinear Optical Dyes Within Organically Modified Silicates, Ian Saratovsky

Honors Theses

The field of photonics involves the use of light to acquire, store, process, and transmit information. Nonlinear optical (NLO) materials are crucial for success in the advancement of photonic devices. Laponite and hectorite host assemblies have been shown previously by our group to induce I -aggregation of nonlinear optical (NLO) dyes and offer facile routes to film fabrication. Head-to-tail alignment (J-aggregation) of the NLO chromophores is a required condition for photonic applications. In this study, tetrabutylammonium, triethylhexylammonium, trimethyldodecylammonium, and trimetylcetylarunonium surfactants were utilized to render the smectic intergallery region organophilic thus facilitating chromophore intercalation and an increased J-aggregated dye fraction. …

A Stereoselective Multi-Component Synthesis Of Alpha-Oxy-Beta-Substituted-Beta-Amino Esters, Avrum L. Joffe

Honors Theses

Previous work has shown that chlorotitanium enolates of methylmethoxy acetate add to aryl aldimines in a stereoselective fashion. Aryl aldimines are non-enolizable, which contributes to their ability to add to the enolates. Previous attempts to add the enolates to enolizable alkyl aldimines were unsuccessful. By using a multi-component process in which the aldimine is synthesized in-situ, we have expanded the scope of this chemistry to the enolizable alkyl aldimines. Furthermore, the multi-component process has proven to be stereoselective for the anti-adduct.

The Use Of Substituted Cyclodextrins In Capillary Electrophoresis For The Separation And Identification Of Methorphan Enantiomers, Colleen Strait

Honors Theses

The goal of this project was to separate the enantiomers levo and dextromethorphan using capillary electrophoresis (CE). Levomethorphan is a controlled substance, and dextromethorphan is an active ingredient in many cough syrups. Methylated-β-cyclodextrins (CDs) are used as additives because the CDs have chiral centers, allowing them to bind differently to the two enantiomers and thereby changing the enantiomer migration times in CE. Dimethyl- β-CD did not separate the levo and dextromethorphans; however the trimethyl-β-CD was successful at producing baseline separation with migration times of roughly 6 minutes. We are optimizing it by changing variables such as type of buffer, buffer …

The Optimization Of Sol-Gels As Sensing Arrays And The Testing Of Sol-Gel Precursors Through The Use Of Fluorescence Measurements Of Eosin-Y, Rachel M. Bukowski

Honors Theses

The purpose of the first project, performed in collaboration with Professor Frank Bright of SUNY at Buffalo, was to optimize the conditions and variables for a Cartesian Technologies Pinprinter to print reproducible spots of sol-gels doped with Ruthenium Diphenylphenathrene (Ru(dpp)32+), an oxygen-sensing complex, on microscope slides. We attempted to optimize these variables by l) the alteration of the printing speed of the sol-gel microarrays, 2) variation of the drying temperature of the gels after they had been printed, 3) controlling the reaction rate of the sol-gel, and 4) various methods of slide pre-treatment. We found that a print speed of …

The Optimization Of Sol-Gels As Sensing Arrays And The Testing Of Sol-Gel Precursors Through The Use Of Fluorescence Measurements Of Eosin-Y, Rachel M. Bukowski

Honors Theses

The purpose of the first project, performed in collaboration with Professor Frank Bright of SUNY at Buffalo, was to optimize the conditions and variables for a Cartesian Technologies Pinprinter to print reproducible spots of sol-gels doped with Ruthenium Diphenylphenathrene (Ru(dpp)32+), an oxygen-sensing complex, on microscope slides. We attempted to optimize these variables by l) the alteration of the printing speed of the sol-gel microarrays, 2) variation of the drying temperature of the gels after they had been printed, 3) controlling the reaction rate of the sol-gel, and 4) various methods of slide pre-treatment. We found that a print speed of …

Novel Synthesis Of 2-Methyl-3, 4, 5-Trichloropyrimidine, Daniel M. Goldman

Theses

A one-step synthesis of the heterocycle 2-methyl-3,4,5-trichloropyrimidine by the cycloaddition of hexachloropropene with acetamidine hydrochloride in methanolic NaOH was attempted. The product was dark amber oil. A by-product of this reaction was sodium chloride. The proposed reaction was expected to proceed via a SN2 nucleophilic displacement of three chlorine atoms on hexachloropropene by acetamidine, the nucleophile. The proposed driving force for this transformation is the lone pair of electrons on the amidine nitrogen along with the electron withdrawing ability of three chlorines on hexachloropropene which induces a partial positive charge on the carbon. It is proposed that the chlorine atoms …

Communicator-In-Chief: Presidential Use Of Television Past, Present, And Future, Jenna Wasson

Honors Theses

This thesis seeks to determine how television has changed as a communication medium for presidents over the past half century. An evaluation of the evolving ways presidents use television to communicate with and to build support from the American people has been conducted. Presidential communication strategies have been identified by drawing primarily from primary sources written by presidents and White House staff. Television technology and the television audience have changed over the years. Presidents have taken a more pro-active, aggressive role in their efforts to harness television for their own purposes. Why have these changes occurred? What impact have these …

Synthesis And Dna Binding Of Cis And Trans-Rucl2 (Dmso)4, Thomas Curran

Honors Theses

The synthesis of both cis and trans-RuCl?(DMSO)? has been reported in literature, and is currently the only way of acquiring these compounds. Because these metallodrugs have shown similar antitumor properties to cisplatin, they are currently under investigation for use in clinical trials as potential chemotherapeutics. It is believed that these drugs act in a way similar to cisplatin by causing intrastrand crosslinking of adjacent guanine residues in DNA. In an attempt to better understand any Ru/DNA interaction for these compounds, both cis and trans-RuCl?(DMSO)? were synthesized with reasonable yields (~40%). The compounds were then characterized by nuclear magnetic resonance (NMR), …

Group 4 Metallocene And Half-Sandwich Derivatives Of Spherosilicate: Preparation Fromsi8o20(Snme3)8 And Their Olefin Polymerization Activity, Suree Saengkerdsub

Doctoral Dissertations

Three metallocene and half-sandwich Group 4 complexes of cuboctameric

spherosilicate (Si8O20(TiCp2Cl)8, Si8O20(ZrCp2Cl)8, and Si8O20(TiCp*Cl2)8) were successfully prepared by the exchange reaction of Group 4 metal chlorides with the spherosilicate starting material, Si8O20(SnMe3)8. These complexes were found to be catalytically active in olefin polymerization. Their preparative reactions clearly demonstrate a synthetically useful route towards many other derivatives of spherosilicate through the Si8O20(SnMe3)8 starting material. A new synthesis of the key precursor, octa(trimethyltin) cuboctameric spherosilicate Si8O20(SnMe3)8, was developed. It was found that most of the waters of hydration of the initial hydrate ([NMe4][Si8O20] @ n H2O, = 60! 70) could be removed …

Conformational Analysis Of Small Peptides By Circular Dichroism, Toni Bowie

Electronic Dissertations and Theses

Reports on peptides that are rich in D-alanine indicate that peptides with this structural motif adopt a specific secondary structure. In this study, two cyclic tetrapeptides cyclo[Leu-D-Ala], where Xaa is Glu or Lys, was studied by circular dichroism (CD). The conformational stability of these peptides was investigated by varying the temperature, solvent, pH, and concentration of the peptide solutions. When these conditions were varied, the CD measurements in each condition did not produce any significant changes. The CD of both peptides exhibits two positive CD bands at 211 nm and 222 nm and a third positive CD band below 190 …

Modulation Of Oxidative Stress Via Benzodiazepines, Chauncey D. Daniels

Electronic Dissertations and Theses

Oxidative damage resulting from generation of oxygen-derived free radicals is thought to be the cause of age-related dysfunction in key organs and tissues. Recent studies suggest that the GABA neurotransmitter system modulates the extent of oxidative damage. If this is true, then a drug that alters GABA neurotransmission, such as diazepam, a drug that facilitates GABA neurotransmission, was tested for its efficacy to lessen oxidative damage to the brain tissue. A total of sixteen Swiss Webster mice were implanted subcutaneously with osmotic mini pumps that provided a constant delivery (3.5 mg/Kg/day) of either diazepam (n=8) or vehicle (50% dimethyl sulfoxide/ …

A Study Of The Photodegredation Of Carbaryl: The Influence Of Natural Organic Matter And The Use Of Silver Zeolite Y As A Catalyst, Marsha Kanan

Electronic Theses and Dissertations

The photodegradation of carbaryl in the presence of Suwannee River natural organic matter (NOM) as well as the presence of AgY zeolites was studied. Two NOM samples were purchased in 2000 and 2001 and labeled as NOM-2000 and NOM-2001, respectively. The synchronous-scan luminescence spectra (SSLS) indicate the presence of different luminophores in the two samples. This suggests that although the compositions of the two NOM samples are similar, isomers composing the NOM mixtures are different. This difference was observed in the effect the two Suwannee River NOM samples had on the photodegradation of carbaryl. In particular, the photodecomposition of carbaryl …

Impact Of Preservative Treatments And Fungal Exposure On Phenolic Fiber Reinforced Polymer (Frp) Composite Material Utilized In Wood Reinforcement, Cihat Tascioglu

Electronic Theses and Dissertations

When wood products are exposed to environmental conditions conducive to biodeterioration, wood preservation becomes a necessity, especially when long-term utilization is desired. Although considerable literature exists on the treatment of laminated timbers and wood composites with wood preservatives, almost no information is available on the exposure of Fiber Reinforced Polymer (FRP) composites to wood preservative chemicals. In this work, FRP material was treated with common preservative chemicals and the effect of wood preservative treatments on mechanical properties of FRP material were investigated. Although the longitudinal elastic modulus was unaffected, some longitudinal strength losses were recorded for CCA and CDDC (water …

Effect Of Kraft Pulping On Oxygen Delignification, Haixuan Zou

Electronic Theses and Dissertations

The objective of the study reported here was to investigate experimentally the effect of the major Kraft pulping variables on the response of brownstock pulps to medium consistency oxygen delignification. Kraft pulping was performed on mixed Northeastern hardwood chips in a laboratory rocking digester. Kraft pulps of kappa number 16 and 20 mL KMnO₄ were produced by pulping under a variety of conditions. The effective alkali (EA) charged to the digester was varied over the range of 12 to 21% while the sodium sulfide content of the pulping liquor was varied between 0 to 30% sulfidity. Cooking temperatures of …

The Chemistry Of Trifluoromethyl Indenes And Trifluoromethyl Indenyl Complexes, Maud J. Urbanski

Seton Hall University Dissertations and Theses (ETDs)

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Separation Of Enantiomers With Chiral Dendrimer, Jie Zhuang

Masters Theses

Chiral dendrimers with .unique ordered structures are especially attractive for the recognition of chiral molecules based on the three point contact model. We have successfully synthesized first generation chiral dendrimers containing L- and D- tryptophan methyl ester moieties and characterized them by NMR, IR, UV-Visible, MS, and optical activity. L-tryptophan methyl ester dendrimer was converted to its acid form in order to attach it to aminopropyl silica for the HPLC separation of enantiomers. The aminopropyl silica containing 1.52mmols/g of NH₂ groups binds about 0.3mmols of dendrimer per gram and has about 0.4mmols of free NH₂ groups per gram. …