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Aluminum and Copper Chemical Vapor Deposition on Fluoropolymer Dielectrics and Subsequent Interfacial Interactions (open access)

Aluminum and Copper Chemical Vapor Deposition on Fluoropolymer Dielectrics and Subsequent Interfacial Interactions

This study is an investigation of the chemical vapor deposition (CVD) of aluminum and copper on fluoropolymer surfaces and the subsequent interfacial interactions.
Date: December 1997
Creator: Sutcliffe, Ronald David
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Determination of the Constants in the System of Methyl Alcohol, Formic Acid, Methyl Formate and Water (open access)

The Determination of the Constants in the System of Methyl Alcohol, Formic Acid, Methyl Formate and Water

Problems presented in this paper concern the chemical equilibrium of methyl alcohol, formic acid, and methyl formate when combined.
Date: August 1939
Creator: Cox, Ross L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Raman Studies of Molecular Dynamics and Interactions in Liquids (open access)

Raman Studies of Molecular Dynamics and Interactions in Liquids

In order to explore the N-H stretching region of aliphatic amines, we performed a study of the Raman spectrum of n-propylamine at various concentrations in cyclohexane. Statistical analysis provided evidence of a second symmetric stretching vibration, which we were able to assign to nonhydrogen bonded NH2 groups. To obtain additional evidence on the existence of monomers in n-propylamine and to further study hydrogen bonding and Fermi resonance in aliphatic amines, we extended the investigation to the analysis of the Raman spectrum of this compound over an extended range of temperature in the neat liquid phase. This study corroborated our finding that the peak previously assigned to the symmetric stretching mode of hydrogen bonded amines is actually composed of two bands. Furthermore, trends in both the resolved band parameters and the Fermi resonance analysis were tabulated, allowing one to monitor the change in the N-H valence region with concentration and temperature.
Date: May 1984
Creator: Friedman, Barry R. (Barry Richard)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Preparation, Properties, and Reactions of Silenes, Silenoids, and 2-Silanobornenes (open access)

The Preparation, Properties, and Reactions of Silenes, Silenoids, and 2-Silanobornenes

The reaction of chlorodimethylvinylsilane with tertbutyllithium was investigated in the presence of several conjugated dienes. In all cases except with 2,5-dimethylfuran, [2+4] cycloadducts of a silene intermediate are obtained in hydrocarbon solvents. The presence of THF in the reaction mixture suppresses the formation of cycloadducts in favor of 1,3-disilacyclobutanes. In the reaction of dimethylethoxyvinylsilane or dimethylmethoxyvinylsilane with tert-butyllithium the main product is the 1,1-dimethyl2-neopentyl-4-(dimethylalkoxysilyl)silacyclobutane. It is concluded that lithium chloride elimination to give silene intermediates occurs in hydrocarbon solvents. In the presence of strong Lewis bases or when the leaving group on silicon is an alkoxy group, the addition reaction giving a-lithiosilanes occurs and products arising from their coupling reactions are obtained.
Date: December 1981
Creator: Pierce, Richard A. (Richard Austin), 1918-2004
Object Type: Thesis or Dissertation
System: The UNT Digital Library
(4+2)-Cycloaddition Reactions of Ketenes; Pyranones (open access)

(4+2)-Cycloaddition Reactions of Ketenes; Pyranones

This study deals with the (4+2)-cycloaddition reactions of 4-π electron compounds with ketenes. Chloroketenes were generated in situ from the corresponding chlorinated acid chlorides in the presence of the ketenophiles. Chloro-, dichloro- and diphenylketenes reacted with 1-methoxy-3-trimethylsiloxy-l,3-butadiene, and 2,4-bis(trimethylsiloxy)-1,3-pentadiene to yield the corresponding dihydropyrans. The dihydropyrans yielded substituted 4-pyranones on hydrolysis.
Date: August 1983
Creator: Agho, Michael O. (Michael Osarenogowu)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Molecular Dynamics and Interactions in Liquids (open access)

Molecular Dynamics and Interactions in Liquids

Various modern spectroscopies have been utilized with considerable success in recent years to probe the dynamics of vibrational and reorientational relaxation of molecules in condensed phases. We have studied the temperature dependence of the polarized and depolarized Raman spectra of various modes in the following dihalomethanes: dibromomethane, dichloromethane, dichloromethane-d2, and bromochloromethane. Among other observed trends, we have found the following: Vibrational dephasing times calculated from the bend) and (C-Br stretch) lineshapes are of the same magnitude in CI^B^. The vibrational dephasing time of [C-D(H) stretch] is twice as long in CD2Cl2 as in CH-^C^, and the relaxation time of (C-Cl stretch) is greater in CI^C^ than in CD2CI2. Isotropic relaxation times for all three stretching vibrations are significantly shorter in C^BrCl than in CI^C^ or CI^B^. Application of the Kubo model revealed that derived modulation times are close to equal for equivalent vibrations in the various dihalomethanes. Thus, the more efficient relaxation of the A^ modes in CE^BrCl can be attributed almost entirely to the broader mean squared frequency perturbation of the vibrations in this molecule.
Date: May 1985
Creator: Chen, Jen Hui
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Regulation of Lactobacillic Acid Formation in Lactobacillus Plantarum (open access)

Regulation of Lactobacillic Acid Formation in Lactobacillus Plantarum

Cyclopropanation of the unsaturated fatty acid moieties of membrane phospholipids is a commonly observed phenomenon in a number of bacterial systems. The cyclopropane fatty acids are usually synthesized during and after the transition from exponential growth to stationary phase, or under such environmental conditions as acidic culture pH, low oxygen tension or high salt concentrations. S-Adenosylmethionine, the ubiquitous methyl group donor, provides the methylene bridge carbon in the reaction catalyzed by cyclopropane fatty acid synthase. Also formed in the reaction is S-adenosylhomocysteine, a potent inhibitor of cyclopropane fatty acid synthase, which is degraded by S-adenosylhomocysteine nucleosidase. This work provides evidence for at least two modes of regulation of lactobacillic acid synthesis, the cyclopropane fatty acid formed from cis-vaccenic acid (cis-11,12-octadecenoic acid), in Lactobacillus piantarum.
Date: December 1980
Creator: Smith, Darwin Dennis
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Study of Low Temperature Silene Generation (open access)

The Study of Low Temperature Silene Generation

The reactions of tert-butyl-, sec-butyl-, and n-butyllithium with dimethylfluorovinylsilane include addition to the double bond to give both silene and silenoid intermediates, fluorine substitution, and a novel vinyl substitution. For the tert-butyllithium reaction, product stereochemistry and trapping experiments using both cyclopentadiene and methoxytrimethylsilane show that silenes are not formed in THF. In hexane about 67% of the 1,3-disilacyclobutanes obtained arise from silene dimerization while 33% are formed by silenoid coupling. In hexane the order of reactivity for addition, t-Bu > sec-Bu > n-Bu, is opposite that for fluorine substitution. The vinyl substitution is most significant with secondary alkyllithium reagents including the tert-butyllithium adduct to dimethylfluorovinylsilane and with sec-butyllithium itself. Evidence for the formation of vinyllithium or ethylene in the process could not be obtained.
Date: August 1985
Creator: Cheng, Albert Home-Been
Object Type: Thesis or Dissertation
System: The UNT Digital Library
GC/MS Analysis of Chlorinated Organic Compounds in Municipal Wastewater After Chlorination (open access)

GC/MS Analysis of Chlorinated Organic Compounds in Municipal Wastewater After Chlorination

A study has been conducted for the qualitative and Quantitative analysis of chlorinated organic compounds in water. The study included the adaptation of Amberlite XAD macroreticular resin techniques for the concentration of municipal wastewater samples, followed by GC/MS analysis. A new analytical method was developed for the determination of volatile halogenated organics using liquid-liquid extraction and electron capture gas chromatography. And, a computer program was written which searches raw GC/MS computer files for halogen-containing organic compounds.
Date: August 1982
Creator: Henderson, James E. (James Edward)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Synthesis of Anthracyclines Related to Adriamycin (open access)

Synthesis of Anthracyclines Related to Adriamycin

This dissertation reports the preparation of several types of anthraquinones structurally related to adriamycin. It describes the synthesis of two types of 2-aminoquinizarin compounds. It also presents two new syntheses of a heterocyclic tetracyclic ring system, similar to the aglicone ring system of adriamycin. A series of 2-aminoquinizarins was prepared by adding several primary amines to quinizarin. Quinizarin was shown to be essentially inert toward secondary amines. Several secondary amine adducts with quinizarin have been prepared, however, by treating the bis-boroacetate ester of quinizarin with the amines. Both types of 2-aminoquinizarin compounds exhibit outstanding potential for possessing antineoplastic activity, and several have been submitted to the National Cancer Institute for testing in their screening program for antineoplastic agents.
Date: May 1981
Creator: White, Roger J.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Electrodeposition of Zinc (open access)

The Electrodeposition of Zinc

This thesis examines the use of zinc for electroplating and compares its use to other metals. Experiments conducted to gather data indicated circumstances which resulted in optimal results.
Date: August 1939
Creator: Flanagin, Charles E.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Quantitative Chemical Analysis of the Hicoria Pecan Nut Kernel (open access)

A Quantitative Chemical Analysis of the Hicoria Pecan Nut Kernel

This thesis explores the Hicoria genus and focuses on the Stuart variety of pecan tree. Experimentation yielded the ash constituents, fats, fat constants, crude fiber, protein, and sugar in shelled pecan samples.
Date: August 1939
Creator: Hollingsworth, Asa Kenneth
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Diffusion of Hydrocarbons Through Rubber Membranes (open access)

Diffusion of Hydrocarbons Through Rubber Membranes

This thesis explores the seperation of isomeric paraffins in organic chemistry and how the resulting mixture of hydrocarbons might be examined.
Date: August 1939
Creator: Long, Loren M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Synthesis of Ketene Thioacetals and Their Monosulfoxide Derivatives and the Thermal Rearrangements of Diallylic Ketene Thioacetals (open access)

Synthesis of Ketene Thioacetals and Their Monosulfoxide Derivatives and the Thermal Rearrangements of Diallylic Ketene Thioacetals

Ketene dimethyl thioacetal monosulfoxide was prepared in 68% overall yield in two steps starting from methylmagnesium chloride. The yield of dithioacetic acid was improved significantly by employing tetrahydrofuran as solvent and using elevated temperatures. A one-pot synthesis of ketene thioacetals from alkyl halides was developed and several ketene thioacetals were prepared by this method. Direct oxidation of ketene thioacetals using m-chloroperoxybenzoic acid provided a general route to ketene thioacetal monosulfoxides. In cases where E and Z isomeric ketene thioacetal monosulfoxides were possible, the E/Z isomeric ratio increased as the substituents on the ketene double bond was increased in size.
Date: August 1982
Creator: Kaya, Riza
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Silene Stereochemistry (open access)

Silene Stereochemistry

The reaction of tert-butyllithium with chloromethylphenylvinylsilane at low temperatures in hexane gave a 48% yield of a mixture of the five isomers of 1,3-dimethyl-1,3-diphenyl-2,4-dineopentyl-1,3-disilacyclobutane, formed by the head-to-tail dimerization of both E- and Z-1-methyl-1-phenyl-2-neopentylsilenes, along with an acyclic dimer. These were separated and their stereochemistry was established by ('1)H- and ('13)C-NMR spectroscopy. The E- and Z-silenes were also trapped as their {4 + 2} cycloadducts with cyclopentadiene, 2,3-dimethyl-1,3-butadiene and anthracene, which also were separated and stereochemically characterized. A consistent mole ratio of 70:30 for the E- and Z-silene adducts is interpreted as evidence for stereochemical induction in the silene generation reaction. It is also suggested that the dimerization of the silenes to give the 1,3-disilacyclobutanes occurs by a nonstereospecific stepwise pathway. When E- or Z-1-methyl-1-phenyl-2-neopentylsilene was generated by the retro-Diels-Alder flow vacuum thermolysis of its corresponding cyclopentadiene or anthracene adduct at temperatures between 400 and 600(DEGREES)C and then trapped with 2,3-dimethyl-1,3-butadiene, the stereochemical distribution of the products is independent of the stereochemistry of the silene precursor, indicating that the silene is not configurationally stable towards cis-trans isomerization at these temperatures. Evidence that the intermolecular ene reaction and the {4 + 2} cycloaddition which occur with 2,3-dimethyl-1,3-butadiene are concerted is presented. …
Date: August 1984
Creator: Lee, Myong Euy
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Synthetic Applications of Ketene Cycloadditions Lactams and Coumarins (open access)

Synthetic Applications of Ketene Cycloadditions Lactams and Coumarins

The objective of this study was to develop new synthetical routes to natural and industrial products utilizing ketene cycioaddition reactions. The cycioaddition of diphenylketene with α,β-unsaturated imines yields (2+2) cycioaddition products, g-lactams. However, electron donating groups, such as dimethylamine, in the 4-position of the α,β-unsaturated imines result in (4+2) cycloaddition products, ∂-lactams. Dichloroketene reacted with α,β-unsaturated imines to yield (4+2) cycloaddition products, g-lactams. Large substituents in the 4-position of a, ^-unsaturated imines resulted in a (2+2) cycioaddition product, β-lactam. The ∂-lactams derived from dichloroketene are easily dehydrochlorinated to the corresponding 2-pyridornes.
Date: August 1984
Creator: Shieh, Chia Hui
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Quantification of Poly(ADP-ribose) in Normal and in DNA-Damaged Cells (open access)

Quantification of Poly(ADP-ribose) in Normal and in DNA-Damaged Cells

This work presents the development of a new highly sensitive and selective chemical assay for poly(ADP-ribose) which is routinely useful for the determination of polymer levels in vivo. This method was used to carefully measure poly(ADP-ribose) levels in normal and in DNA-damaged cells. The results of these studies strongly suggest that synthesis of poly(ADP-ribose) is involved in some aspect of DNA repair. A review of the literature is presented in the introduction of this work. Poly(ADP-ribose) synthesis has been implicated in aspects of transcription, in DNA syn thesis, and in DNA repair largely based on evidence from in vitro studies. It is apparent that current methodology has not allowed the routine quantification of poly(ADP-ribose) in vivo, hence the lack of i^n vivo data concerning the function(s) of the polymer. The body of this work presents the development of two chemical methods for the quantification of poly(ADP-ribose) and the application of one of these methods to the measurement of polymer levels in normal and DNA-damaged cells. Preliminary studies are presented on the utilization of combined gas chromatography/mass spectroscopy for the selective quantification of nucleoside derivatives. A second method makes use of the unique chemistry of the polymer for quantification. The polymer …
Date: December 1980
Creator: Sims, James L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Attempt to Produce a High Octane Gasoline from C4 Hydrocarbons (open access)

An Attempt to Produce a High Octane Gasoline from C4 Hydrocarbons

This thesis presents the results of an experiment conducted to discover if selenic acid or monazite sand are possible catalysts that can be used for the alkylation of isobutane and isobutene.
Date: June 1939
Creator: Scott, Howard Winfred
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Chlorosulfonic Acid Reactions with Saturated Hydrocarbons (open access)

Chlorosulfonic Acid Reactions with Saturated Hydrocarbons

This thesis examines the reactions of hydrocarbons exposed to chlorosulfonic acid in order to establish the reaction rate and associated molecular structure of each compound.
Date: May 1939
Creator: Stubblefield, H. L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Electrodeposition of Cadmium (open access)

Electrodeposition of Cadmium

This thesis presents findings of experiments conducted to determine the most feasible method to electroplate metal.
Date: August 1939
Creator: Bond, T. Jackson
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Comparative Quantitative Study of the Common Elements Found in the Hackenberry (open access)

A Comparative Quantitative Study of the Common Elements Found in the Hackenberry

This comparative study attempts to determine the importance of soil fertility in determining how much of an element a plant absorbs.
Date: June 1939
Creator: Bailey, Duward W.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Purification of HMG-CoA Reductase and Regulation by Protein-Lipid Interactions (open access)

Purification of HMG-CoA Reductase and Regulation by Protein-Lipid Interactions

The enzyme 3-Hydroxy-3- Methylglutaryl Coenzyme A Reductase catalyzes the rate limiting step of hepatic cholesterol biosynthesis and is unique among the enzymes in the early part of the pathway in that it is membrane bound. This gives rise to potential regulation of the enzyme through interactions with the endoplasmic reticulum membrane. A purification procedure has been developed which consistently produces enzyme of high specific activity. In order to fully characterize the interactions between HMG-CoA reductase and the lipids in its immediate environment, HMG-CoA reductase was purified to homogeneity and shown to be a protein-lipid complex.
Date: December 1982
Creator: Brent, Lynn G. (Lynn Gran)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Chemical Analysis of Yellow Dent Corn (open access)

A Chemical Analysis of Yellow Dent Corn

This study examines history, climate, and distribution in relation to the chemical content of yellow dent corn.
Date: August 1939
Creator: Hamby, R. B.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Dark Adaptation Study of College Men and Women (open access)

A Dark Adaptation Study of College Men and Women

This study is the result of tests conducted to determine the adaptability of the human eye to darkness.
Date: August 1940
Creator: Henry, Archie
Object Type: Thesis or Dissertation
System: The UNT Digital Library