Digital Commons Network^™

The Utilization Of High Sensitivity Noble Gas Mass Spectrometry In The Detection Of Iodine-129 And Plutonium-244, Mervet S. Boulos

Doctoral Dissertations

"Mass spectrometric analysis of the xenon isotopes in natural gas wells demonstrates that radioactive isotopes of element number 53 (I) and element number 94 (Pu) were present at the time of the Earth's formation. Evidence for the now extinct nuclide¹²⁹I (t_1/2 = 17 x 10⁶ years) was found in CO₂ -rich gas while evidence for the now extinct ²⁴⁴Pu (t_1/2 = 82 x 10⁶ years) was discovered in other natural gas wells. The amounts of ¹²⁹I in thyroids was measured by combining neutron activation analysis with noble gas mass spectrometry. The current …

Substituent Effects On The Magnetic Resonance Spectra Of 1, 4-Disubstituted Benzenes, Holger Er-Chah Chen

Doctoral Dissertations

"The Nuclear Magnetic Resonance spectra of five complete series of para-substituted benzenes have been investigated: the benzoic acids, benzonitriles, benzoyl chlorides, methyl benzoates and nitrobenzenes. Precise values of aromatic proton chemical shifts and coupling constants were obtained from LAOCOON3 computer analyses of the spectra. Using the relative internal chemical shift technique of Beachell and Beistel, excellent linear correlations among all five series were found. All substituents gave proton shifts which lay on the least-squares line, so it is concluded that all substituents are well behaved. Using the correlation plots the chemical shifts of the aromatic ring protons can be predicted …

Selected First Row Transition Metal Coordination Compounds Of 2-(N-Aminomethyl)-3-Quinuclidinone Chelates, Richard Cecil Dickinson

Doctoral Dissertations

"As part of a project directed towards elucidating the characteristics of ligands which coordinate to give complexes having tetrahedral structures, a study of chelates containing the bulky quinuclidine group has been made. With 2-(N-morpholinylmethyl)-3-quinuclidinone (MQN), complexes having the general formula M(MQN)X₂ were prepared where the metal ion was Co(II), Ni(II), Fe(II), Cu(II), and Mn(II). The ligands 2-(N-piperidinylmethyl)-3-quinuclidinone (PQN) and 2-(N-dimethylaminomethyl)-3-quinuclidinone (DQN) were prepared along with the analogous cobalt(II) chloride complexes. The series of complexes Co(MQN)X₂ where X = Cl, Br, or I were prepared, and magnetic susceptibilities and spectral data obtained. They have room temperature magnetic moments in the range …

Condensation And Sublimation Of Carbon Dioxide And Water Molecules At Cryogenic Temperatures, Victor Cazcarra

Doctoral Dissertations

"Measurements of the condensation coefficient of CO₂ and H₂O have been made using a molecular beam and quartz crystal microbalances. The dependence of the condensation coefficient on variables such as population density on the substrate, temperature of the substrate, molecular beam intensity and temperature of the molecular beam, was investigated. The results are explained using heterogeneous nucleation theory for low density population, and a new approach for high density population is presented. The rate of sublimation of these two gases was measured directly. The results are reported in terms of vapor pressure in the range 10⁻⁹ to 10⁻⁴ Torr. The …

Studies Of Neutron Capture Produced Rare Gas Isotopes In Rocks And Minerals Containing Chlorine, Selenium And Tellurium, David E. Sinclair

Masters Theses

"Noble gas mass spectrometry was used to study rare nuclear processes in terrestrial rocks and minerals. An excess of ³⁶Ar was detected in a chlorine-rich rock. The excess ³⁶Ar has been produced in rocks near the earth's surface due to capture of cosmic-ray-produced neutrons on ³⁵Cl. Measurement of ³⁶Ar formed by the ³⁵Cl(n, γ)³⁶Cl(β^-)³⁶Ar process makes possible a new method for determining the surface residence time of chlorine-rich minerals

Excess ⁸²Kr and excess ⁸³Kr were detected in selenium-rich ores. The excess ⁸²Kr results from double beta …

A Study Of Some Complexometric Titrations In Nonaqueous Solvents, Ngo The Hung

Masters Theses

"Complexometric titrations of calcium, zinc and lead with polyaminocarboxylic acids: ethylenediaminetetraacetic acid (EDTA), 1,2-diaminocyclohexanetetraacetic acid (DCTA), ethyleneglycol-bis(2-aminoethylether)tetraacetic acid (EGTA) and tetraethylenepentamine (tetren) have been investigated and compared in the following organic solvents: methanol, dimethyl formamide, dimethyl sulfoxide and methyl ethyl ketone. Various end point detection methods have been used: direct visual titration with metallochromic indicators and instrumental detection by photometry, potentiometry (mercury electrode and lead ion selective electrode) and amperometry. Calcium, zinc and lead can be determined up to trace levels (ppm) under specific conditions. A concrete application of this thesis is the determination of zinc or calcium in a …

Adsorption Of Dichromate At The Air-Solution Interface, Josephine Juch Wang

Masters Theses

"The adsorption of dichromate ion with the surfactants, tetradecylpyridinium bromide and tetradecyltrimethylammonium bromide at the air-solution interface was studied by surface tension and turbidity measurements in order to better understand the process of ion flotation. Surface tension measurements were used to study the effect of dichromate ion concentration on precipitation in dilute surfactant solutions. At higher concentration, near and above the cmc, light scattering was used to detect precipitation. The concentration of dichromate required to cause precipitation decreases with increasing surfactant concentration until the erne is approached, after which increasing concentrations of dichromate are required with increasing concentration of surfactant. …