Physical Sciences and Mathematics Commons^™

Determination Of Aldehydes And Ketones In The Gas Phase, Clyde A. Kelly

Honors Theses

A recently developed method for the quantitative detection of carbonyl compounds in ambient air was investigated, specifically in order to further standardize and improve the process. The method involves drawing a gas phase sample of carbonyl compounds through impingers containing a 2, 4-Dinitrophenylhydrazine solution is then injected directly into the hplc for separation on a reversed phase column and quantitative determination by UV absorption at 254 nm and 360 nm simultaneously. The critical feature of the method (based upon a standard analytical derivatization reaction) is the use of the acetonitrile solvent. This allows for direct injection of the sampling solution …

Cationic Copolymerization Of Styrene And Beta-Pinene: The Effect Of Solvent On Monomer Reactivity Ratios, George Yusun Paik

Honors Theses

Copolymers of styrene and B- pinene were synthesized at 30 degrees Celcius in methylene dichloride, carbon tetrachloride, and nitrobenzene. NMR analysis was used to determine the mole percent of styrene and B-pinene in the copolymer. These data were used to calculate monomer reactivity ratios in the three different solvents. It was also found that the styrene reactivity ratio increased when solvents with low dielectric constants were used. The B-pinene reactivity ratio also increased as the dielectric constant of the solvent increased. Pyrolysis and gas chromatography indicated that copolymerization may not have occurred in nitrobenzene and carbon tetrachloride if the mole …

Syntheses And Fluorescence Properties Of Sterically-Hindered Esters Of 9-Anthroic Acid, Richard Leslie Dubs

Honors Theses

For over a decade, Professor Thomas C. Werner and his students have been studying the unusual florescence properties of methyl-9-anthroate. In the ground state of this ester, the carboxyl group lies perpendicular to the anthracene rings due to steric inhibition by the peri hydrogens. Werner has postulated that, upon excitation, the carboxyl group rotates to form a planar configuration with the anthracene rings, and that this rotation is the cause of the unusual spectral properties. In our work, we have attempted to prove or disprove this hypothesis. We have chosen to synthesize analogues of methyl-9-anthroate in which carboxyl group rotation …

The Apple Ii, Daniel M. Laby

Honors Theses

The apple II+ microcomputer was interfaced to an Aminco-Morrow stopped-flow Apparatus. This interface package can be broken into two parts; the hardware, or electrical connections necessary to link the two instruments, and secondly, the software, or programs written to control the interface package. A circuit was constructed as part of the interface hardware. This circuit consisted of several operational amplifiers connected in such a way as to transform the output voltage of the stopped-flow into one acceptable by the Apple computer. The software for this interface package is extensive. Programs were written that allowed the user to initialize the correct …

Dmf Extractability As A Predictor Of Plasticity In Bituminous Coals, Jana Whitt

Masters Theses & Specialist Projects

Plasticity is a phenomenon of certain coals that is not completely understood. Some bituminous coals go through a softening and swelling state upon heating before they re-solidify. It is this softening and swelling state that is labeled as the "plastic state" of the coal. Concurrent with the plastic state of the coal, thermal decomposition of the coal takes place. Several low molecular weight gases are also evolved. These occur at a temperature of approximately 450° C.

The plasticity of a coal is a good indication of the coking ability of a coal. Plastic coals tend to give higher yields in …

The Combined Effect Of Cu And Zn On Selenastrum Capricornutum, Helmer Colonia-Roque

Dissertations and Theses

It has been demonstrated that the toxicity of heavy metals depends on their chemical speciation and can be related to their free ion activities, rather than the total metal concentrations. The objective of this study was to determine the effect of combined free ions of zinc and copper on the toxicity to the green alga Selenastrum capricornutum. This alga was grown in a defined medium, under controlled laboratory conditions, with a varying range of zinc and copper concentrations. The growth rate of the alga was inhibited at pZn = 5.93 or at pCu = 7.24. The results suggest that …

Photochemical Energy Storage (Photosensitized Isomerization Of Norbornadiene To Quadricyclane By Copper(I) Complexes), Dennis J. Fife

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research has focused on the sensitized photoisomerization step of a solar energy storage system based on the interconversion of norbornadiene (NBD) and quadricyclane (Q). Sensitizers studied in the photoisomerization were arylphosphine complexes of copper(I) halides [(Ph₃P)₃CuX, (MePh₂P)₃CuX, (DIPHOS)CuCl; X = Cl, Br, I and DIPHOS = Ph₂P(CH₂)₂PPh₂]. The lowest electronic excited state of the complexes can be an effective triplet energy sensitizer as evidenced by a maximum quantum yield of 1.0 with (MePh₂P)₃CuX. The sensitization mechanism of the L …

Kinetic & Spectral Studies Of Copper(Ii)-4,4',4",4'"-Tetrasulfophthalocyanine In Aqueous Solution, Stephen Scholl

Masters Theses & Specialist Projects

The monomer-dimer equilibrium of CuTSPC^4- was examined by spectral methods in aqueous solution over a total dye concentration of 2 x 10^-8M to 8 x 10^-7M at 24°C. The value obtained for the dimerization constant, KD,was 1.1 x 10⁷M^-1 which is smaller than literature values. However, the discrepancy is not appreciable considering the differences in the methods used and the experimental conditions of the different solutions. Spectral measurements of the dimerization constant were made at only one temperature since the spectral changes were quite small when the temperature was varied. This observation …

Analytical Pyrolysis Of Eastern Oil Shales, Lizbeth Sturgeon

Masters Theses & Specialist Projects

The Sunbury shale and the Cleveland member of the Ohio shale were studied utilizing the technique of analytical pyrolysis (pyrolysis gas chromatography). The effects of ceiling temperature, heating rate, and pyrolysis interval on the pyrolysis yield and relative product distribution for these eastern oil shales were observed. Carefully monitored pyrolysis of the shale allows separation of high and low volatile components and measurement of the relative peak areas in the pyrogram provides the yield of the high and low volatile fractions. Linear temperature ramps of 5000, 2000, and 100°C per second were employed. Ceiling temperatures of 450°C to 950°C and …

Cell-Mediated Immunity Of The Dog Lung And Effects Of Inhaled 239puo2 Or Pulmonary Tumors, Jennifer Baker Galvin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cell-mediated immunity (CMI) in the lung has not been well characterized due to the lack of applicable tests. A major objective was to define pulmonary CMI serially in immunized and control lung lobes using the leukocyte procoagulant (LPCA) assay in young adult dogs. This was compared to a standard, but less reproducible CMI assay, macrophage migration inhibition facet (MIF). The CMI response, as measured by the LPCA assay, peaked in the blood 7 days after lung immunization. The pulmonary CMI response measured with cells obtained by bronchial lavage from the immunized and control lung lobes peaked at 9 to 12 …

Cow Brain Glutaminase: Purification And Influence Of Phosphate And Borate Ions On Its Activity And Molecular Weight, Mahnaz Badamchian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An efficient and simple purification procedure for cow brain glutaminase (L- glutamine amidohydrolase, EC 3.5.1.2) is described. The main steps consisted of acetone extraction and French press treatment in the presence of phosphate ions, precipitation of nucleic acids and lipids by 0.08 % protamine·S04 and high speed centrifugation (300,000xg), ammonium sulfate fractionation, and gel filtration on Sepharose 4B first as the low molecular weight and then as the aggregated form. The yield was 22% and the final preparation had a specific activity of 142 μmoles/min/mg. The purification was more than 8000-fold over crude brain homogenate. The enzyme showed one strong …

Studies In Peptide Synthesis Towards The Lanthionine Analog Of Des-N-Tetramethyl Triostin A, Ganesh Devdas Kini

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies have been carried out towards the synthesis of bicyclic octadidepsipeptide lanthionine 4, an analog of des-N-tetramethyl triostin A. Starting with a symmetrical lanthionine unit 5 (R₁, R₃ = Me; R₂, R₄ = t-butyloxycarbonyl), synthesized from the corresponding cystine by contraction with hexaethylphosphorus triamide, linear octadidepsipeptides 29 and 32 were synthesized.

Attempted cyclizations of 29 and 32 to the bicyclic octapeptide were unsuccessful.

The failure of the symmetrical approach to 4 prompted the synthesis of an unsymmetrical lanthionine unit with appropriate compatible protecting groups. Attempts to synthesize unsymmetrical lanthionines by nucleophilic displacement on …

Kinetics And Mechanism Of Acylation Of Amines With 2-Naphthoyl Azide, Abraham L. Faburada

Dissertations

The reaction of 2-naphthoyl azide with primary and secondary amines in protic and aprotic solvents follows second-order kinetics. The effect of increasing solvent polarity is shown to increase the rate of reaction. For amines of similar basicity, the rate of reaction decreases with increasing steric hindrance on the amine. The changes in free energy and entropy of activation for n-butylamine and cyclohexylamine are in accord with steric requirements of amines. For amines of similar steric hindrance, the rate of reaction increases with increasing amine basicity. The mechanism of addition-elimination involving the formation of a tetrahedral intermediate is consistent with the …

The Effects Of Various Chemical Treatments On The Surface Area Of Coals, Maria Margaret Ludvig

Dissertations and Theses

Surface areas of most American coals are small when measured by N₂ adsorption at 77 K and large when measured by CO₂ adsorption at 298 K, implying that the majority of the pores are less than 5 Å in diameter. This small pore size would restrict many gaseous and liquid reactants from entering the internal pore system of the coal, and hence, reduces the efficiency of coal conversion. Therefore, if the surface area, as measured by N₂ (77 K), could be increased, that is, to increase the pore size, the conversion of coal into useful products should …

Density Functional Calculations For Liquid Metal Surfaces, Jerry Goodisman, M-L Rosinberg

Chemistry - All Scholarship

Various forms for the ion density profiles of Cs and Na have been tested in the density functional formalism. The large oscillations expected for Coulombic systems are largely suppressed by the pseudopotential. While oscillatory profiles give some improvement in surface tension, the values obtained are still about twice the experimental ones. It is concluded that the treatment of the pseudopotential or the gradient expansion of the functional is responsible for the unsatisfactory results obtained.

On Surface Properties Of The One-Component Plasma, M-L Rosinberg, J-P Badiali, Jerry Goodisman

Chemistry - All Scholarship

We consider a plasma of point ions in the presence of a non-uniform neutralising background. This background. the source of an external field, may have some of its parameters (density, form of surface profile, etc) modified, as long as the total charge is maintained. By considering such modifications in the context of the density-functional formalism for the ions, we prove sum rules giving the first and second moments of the ion density p(z) in terms of other properties (bulk pressure and temperature derivative of surface tension). The Poisson-Boltzmann functional is considered in detail. We show that the first and second …

General Correction For Electrode Sphericity In Voltammetry Of Nernstian Systems, Jerry Goodisman

Chemistry - All Scholarship

The current is considered at a stationary reversible spherical electrode whose potential E(t) as a function of time is given, such that E(t) determines the ratio of oxidized to reduced species at the electrode surface. Writing the current as that for planar geometry, I0, plus corrections for sphericity, we derive formulae for the corrections. The first two are expressed as integrals over I0, with no explicit dependence on the potential, for any form of E(t), and whether the reduced species diffuses into the electrode or into the solution. If the ratio of diffusion constants for oxidized and reduced species is …

Contribution Of The Metal To The Differential Capacity Of An Ideally Polarisable Electrode, Jerry Goodisman, Jean Paul Badiali, Martin Luc Rosinberg

Chemistry - All Scholarship

We consider the response of the metal in the ideally polarisable electrode to charging of the electrode, using a model for the metal surface in contact with the solvent of the electrolyte phase previously presented by us in this journal. We show that the effect of the solvent on the electrons of the metal cannot be considered to be simply that of a repulsive barrier. When the electrode charge varies, qM(dip), the metal contribution to the double layer, is modified, implying a contribution which varies along the electrocapillary curve. By considering an electrostatic interaction between metal and solvent, we find …

Flow Injection Calibration Methods For Atomic Absorption Spectrometry, Julian Tyson

Chemistry Department Faculty Publication Series

No abstract provided.

Preliminary Rovibrational Analysis Of The Nν6+Ν1−Nν6 Vibration In Hcn⋅⋅⋅Hf, E. Kyrö, K. Mcmillan, M. Eliades, D. Danzeiser, P. Shoja-Chaghervand, Shannon Lieb, J. W. Bevan

Scholarship and Professional Work - LAS

A preliminary rotation‐vibration analysis of the n=0 and n=1 subbands associated with the nν₆+ν₁−nν₆ hydrogen‐bonded vibration in HCN⋅⋅⋅HF has been completed. The following excited staterotational constantsB′ and band origin frequencies ν₀ have been determined for the complex. The results are consistent with a rotation‐vibration interaction constant α₁=−68.3±1 MHz which correlates with an excited stater(N⋅⋅⋅F) internuclear distance of 2.762 Å, a decrease of 0.034 Å relative to the ground state.Excited state lifetimes associated with assigned transitions are demonstrated to be …

Fluorine, Richard H. Langley, Larry Welch

Faculty Publications

Considering the long time in which fluorine compounds have been used it seems rather surprising that it was not isolated as an element until 1886. This long delay was not due to lack of effort, but to the reactivity of fluorine and the hazards of working with it and many of its compounds.

The Phosphacylium Ion: Evidence For Its Existence As An Intermediate In Reactions Of Organophosphates, Thomas D. Matus

Electronic Theses and Dissertations

Prior to this work, no strong evidence existed which unequivocably proved the existence of phosphacylium ions as intermediates in reactions of this type. It is the object of this study to look into nucleophilic substitution at phosphorus, and the intermediates of these possible dissociative type reactions.

A Statistical Interpretation Of The Rotational Temperature Of No Desorbed For Ru(001), Stephen E. Bialkowski

Stephen E. Bialkowski

A simple model of the rotational state of NO prior to thermal desorption from Ru(001) surface is developed in terms of the rotational heat capacity. The predicted rotational temperature of the desorbed species is consistent with known data on this system. The model is extended to predict translational energy anisotropy in the desorbed NO.

Use Of Hydroelectric Dams To Control Evaporation And Salinity In The Colorado River System, Larry J. Paulson

Publications (WR)

The main stem reservoirs on the Colorado River comprise one of the largest and most heavily used freshwater bodies in the nation. These reservoirs (Lake Powell, Lake Mead, Lake Mohave and Lake Havasu) can store up to 53,590,400 acre-feet of water at their maximum capacities. Nonetheless, local water shortages still exist in some areas of the Colorado River Basin. There is also concern that salt concentrations are approaching levels that could severely affect municipal and agricultural uses. Water shortages will become even more acute as demands for water increase with continued urban and agricultural development in the basin.

Water conservation …

The Effects Of Impoundments On Salinity In The Colorado River, Larry J. Paulson, John R. Baker

Publications (WR)

The increase in salinity of our western rivers has been identified as one of the most serious water quality problems in the nation. This is of special concern in the Colorado River where salinity has increased from pristine levels estimated at 380 mg/1 to present-day levels of 825 mg/1 at Imperial Dam. Flow depletions, associated with decreased runoff and increased evaporation and diversions, coupled with high salt loading from natural and man-created sources are considered the primary causes for rising salinity in the river. The urban and agricultural development projected to occur in the basin through this century could deplete …

Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Vivó Acrivos, S.S. P. Parkin

Faculty Publications, Chemistry

We have measured XANES (X-ray Absorption Near Edge Spectra) near the Re Li (i=l,II,III) edges in (TMTTF)2Re04 and (TMTSeF) 2Re04 and the Se K edge in the latter compound. An important dependence of the XANES at the Se K edge on the polarisation of the incident beam with respect to the crystal axes was observed, whose interpretation can give information on the symmetry of the unoccupied conduction band states. The positions of the Re L edges were compared with those in several inorganic compounds containing Re in various oxidation states, and were found to be, within experimental error, the same …

Solvolysis Of 1-T-Butylvinyl Trifluoromethanesulfonate, Barbara L. Gross

Dissertations, Theses, and Masters Projects

No abstract provided.

Microcomputer-Assisted Colorimetric Determination Of Iron, A. M. Hoyt Jr.

Journal of the Arkansas Academy of Science

No abstract provided.

Chemistry, Norman Kulevsky

UND Departmental Histories

This departmental history was written on the occasion of the UND Centennial in 1983.

Role Of D Functions In Ab Initio Calculation Of The Equilibrium Structure Of H2s–Hf, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Full geometry optimizations are performed to determine the equilibrium geometry of the hydrogen‐bonded complex H₂S–HF. The angle between the plane of the H₂S moiety and the H‐bond axis calculated with the 4–31 G basis set is 106° as compared to the experimental value of 91±5°. This quantity is reduced significantly when d orbitals are added to the basis set, yielding an angle within experimental error of 91°. (AIP)