Physical Sciences and Mathematics Commons^™

“Macromolecules 86": An International Conference On Functional Polymers And Biopolymers, Otto Vogl, Geoffrey C. Eastmond

Emeritus Faculty Author Gallery

No abstract provided.

Influence Of Dna On The Rate Of Porphyrin Metallation, Robert F. Pasternack, E. J. Gibbs, R. Santucci, Stephanie A. Schaertel , '86, Panayiotis A. Ellinas , '87, Stanley C. Mah , '87

Chemistry & Biochemistry Faculty Works

Poly(dG–dC)₂ and poly(dA–dT)₂ have marked influences on the rate of insertion of copper(II) into cationic porphyrins reflecting the interaction mode of the porphyrin with the nucleic acid.

Comment On ‘‘Relations Between Microscopic And Macroscopic Lowest-Order Optical Nonlinearities Of Molecular Crystals With One- Or Two-Dimensional Units’’, K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

An algebraic error in an earlier paper [J. Zyss and J. L. Oudar, Phys. Rev. A 26, 2028 (1982)] led to an interpretation regarding the desirable polarizability characteristics of a molecule for second-harmonic generation in crystals which is opposite to that actually desired. Optimum response is obtained from crystals comprised of molecules with significant in-plane polarizabilities.

“Macromolecules 86": An International Conference On Functional Polymers And Biopolymers, Otto Vogl, Geoffrey C. Eastmond

Otto Vogl

No abstract provided.

River Discharge Study, Laughlin, Nevada: Field Survey Data, 1987, B. Dennis Hugh, David L. Stringfield, Jill C. Bicknell, Robert A. Ryder, Clark County Sanitation District, Nevada

Publications (WR)

A report of the first field data collection effort for the Laughlin River Discharge Study, conducted by Kennedy/Jenks/ChiIton in February, 1987, on the Mohave Reach of the Colorado River. This report also serves to transmit the laboratory analysis reports for all of the analyses performed and summary tables of the results.

This report is organized as follows:

1. Field Conditions and Methodology

2. Summary of Sampling and Analysis Results

3. Deviations from the Proposed Sampling Program

4. Recommendations for Future Sampling

5. Attachments:

A. Climatological Data

B. Davis Dam Average Hourly Releases

C. Laboratory Analysis Reports

University Of Missouri-Rolla Cloud Simulation Facility: Proto Ii Chamber, Daniel R. White, James L. Kassner, John C. Carstens, Donald E. Hagen, John L. Schmitt, Darryl J. Alofs, Alfred R. Hopkins, Max B. Trueblood, Max W. Alcorn, William L. Walker

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Graduate Center for Cloud Physics Research at UMR Has Developed a Cloud Simulation Facility to Study Phenomena Occurring in Terrestrial Clouds and Fogs. the Facility Consists of a Pair of Precision Cooled-Wall Expansion Chambers Along with Extensive Supporting Equipment. the Smaller of These Chambers, Described in This Article, is Fully Operational, and is Capable of Simulating a Broad Range of In-Cloud Thermodynamic Conditions. It is Currently Being Used to Study Water Drop Growth and Evaporation for Drops Nucleated (Activated) on Well-Characterized Aerosol Particles. Measurements Have Been Made Not Only for Continuous Expansions (Simulated Updraft) But Also for Cyclic Conditions, …

Kinetics Of The Metal-Exchange Reaction Between N-(2-Pyridylmethyl)Iminodiacetatonickel(N) And Copper(Ii), Kassahun W. Beyene

Masters Theses

The reaction between N-(2-pyridylmethyl)iminodiacetatonickel(II) and copper(II) was studied spectrophotometrically between pH 2.30 and 3.30 over a 10-fold variation in copper concentration at an ionic strength of 1.25M, and a temperature of 25.0+0.1^oC. The reaction is first order in both NiPyIDA and copper(II). Terms involving proton attack and a copper dependent dissociation of the nickel complex were resolved from the data. Evidence is given for a stepwise unwrapping mechanism PyIDA from the nickel complex, followed by copper attack to give a dinuclear intermediate. A general mechanism is presented which is consistent with the kinetic data.

Comparisons to analogous nickel-aliphatic …

The Partial Oxidation Of Methane To Methanol & Formaldehyde, Terry Matthews

Masters Theses & Specialist Projects

The conversion of methane into methanol is viewed as one approach to utilizing the vast reserves of natural gas.

One such prospect for the utilization of natural gas is the partial oxidation of methane to methanol. Methanol ranks high on the commodity market. As a liquid it is easily transportable and therefore skirts the issue of vast amounts of a gas having to be transported either by pipeline or by liquifying.

The catalytic partial oxidation of methane to methanol is investigated. Two different reactor systems are employed. The first system is a fixed bed system. The second is a fluid …

Effect Of Polymerization Conversion On The Experimental Determination Of Monomer Reactivity Ratios In Copolymerization, Sevim Zeynep Erhan

Dissertations

In this study the comparison of the methods used to calculate monomer reactivity ratios from experimental copolymer composition data is targeted.

For this purpose, nine samples of each of nine different concentrations of styrene-methyl methacrylate monomer mixtures were prepared. These mixtures were then polymerized for different times ranging from one to nine hours and the percent conversion to copolymer was determined.

The compositions of these copolymers were determined by their refractive index increments measured in two different solvents. Ultraviolet absorption spectroscopy was also studied as a possible method to find copolymer compositions. Though this method has been used previously, UV …

Investigation Of The Synthesis And Polymerization Behavior Of Vinyl Benzoate, Selim Mehmet Erhan

Dissertations

The goal of this study is to present a method that gives higher conversions and molecular weights for the polymerization of vinyl benzoate than obtained in previous investigations.

Polyvinyl benzoate has benzene rings attached to the backbone chain, therefore is hard and rigid. This is a characteristic which has a large application area. However previous studies in polymerizing vinyl benzoate with bulk and solution polymerizations reported low yields and troublesome crosslinking, which has limited its application. Emulsion polymerization method has the advantage of giving high polymerization rates together with high molecular weights, and therefore was chosen as the method for …

First Polymer Discussions Of Dresden In Gaussig: Polymer Blends, Otto Vogl, Elizabeth Klemm

Emeritus Faculty Author Gallery

No abstract provided.

First Polymer Discussions Of Dresden In Gaussig: Polymer Blends, Otto Vogl, Elizabeth Klemm

Otto Vogl

No abstract provided.

Synthesis Of Polymers And Polymer Liquid Crystals: A Euchem Conference In Lahti, Finland, Otto Vogl, Franciska Sundholm

Emeritus Faculty Author Gallery

No abstract provided.

Optimization Of Effective Nonlinear Coefficients For Second-Harmonic Generation In Molecular Crystals , K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

Conditions for the design of organic solids capable of optimum nonlinear optical behavior are investigated. Generalized expressions describing optimum phase-matching conditions in crystals of monoclinic symmetry and having one-dimensional hyperpolarizabilities are obtained. The results are applied to specific organic molecular solids. An anisotropic in-plane molecular polarizability is shown to provide the best condition for second-harmonic generation in these systems.

Synthesis Of Polymers And Polymer Liquid Crystals: A Euchem Conference In Lahti, Finland, Otto Vogl, Franciska Sundholm

Otto Vogl

No abstract provided.

Gas Permeation Measurements On Small Polymer Specimens, Karen S. Burns

Chemistry & Biochemistry Theses & Dissertations

Mass spectrometry was used to measure oxygen and nitrogen permeabilities while polarography was used to measure oxygen permeabilities for several contact lens materials. Applicable sample holders were designed and fabricated to accommodate curved and flat specimens with surface areas of 0.5 cm² and 1.0 cm² and thicknesses between 0.025 mm and 0.500 mm. A prepared standard was used to calibrate the mass spectrometric analyses.

The oxygen permeability values determined by mass spectrometry were significantly greater than those determined by polarography. This was attributed to the phase boundary phenomena and the limiting oxygen permeance of water inherent in the …

Ua66/7/2 Hilltopper News, Wku Chemistry

WKU Archives Records

Newsletter created by and about the WKU Chemistry department.

Investigation Of Complex Formation By Oligomers Of Cytosine And Guanosine, Steven Roberts Davis

Chemistry & Biochemistry Theses & Dissertations

Duplex formation between oligo(C:G) _n where n=3 to 4 was shown not to occur under conditions favorable for duplex formation between poly G and poly C. Instead, a stable guano sine self-structure was found to form which a T_m of 50°C for (Gp)₃ and 80°C for (Gp)₄ at strand concentrations of 10^-5M in 1M NaCl. Neither a duplex nor a self-structure formed in the absence of salt.

Oligomers of guanosine and cytosine were obtained by basic hydrolysis and separated according to chain length using DEAE Sephadex column chromatography. Separation of cytosine oligomers with chain lengths …

Determination Of Netropsin-Dna Binding Constants From Footprinting Data, Brian Ward, Robert Rehfuss, Jerry Goodisman, James C. Dabrowiak

Chemistry - All Scholarship

A theory for deriving drug-DNA site binding constants from footprinting data is presented. Plots of oligonucleotide concentration, as a function of drug concentration, for various cutting positions on DNA are required. It is assumed that the rate of cleavage at each nucleotide position is proportional to the concentration of enzyme at that nucleotide and to the probability that the nucleotide is not blocked by drug. The probability of a nucleotide position not being blocked is calculated by assuming a conventional binding equilibrium for each binding site with exclusions for overlapping sites. The theory has been used to evaluate individual site …

Observation Of An Oxygen Isotope Effect In Yba2Cu3O7, Kevin J. Leary, Hans Conrad Zur Loye, Steven W. Keller, Tanya A. Faltens, William K. Ham, James N. Michaels, Angelica M. Stacy

Faculty Publications

A small decrease in T_c of 0.3 K to 0.5 K is observed when as much as 90% of the ¹⁶O in YBa₂Cu₃O₇ is substituted with¹⁸O. This result is consistent with our observation that there is an oxygen isotope effect in La_1.85Sr_0.15CuO₄, but in contrast with previous reports that there is no isotope effect for YBa₂Cu₃O₇. This new result suggests that phonons play an important role in the electron-pairing mechanism in YBa₂Cu₃O₇.

Molecular And Electronic Structure Of Si3h6, Mark S. Gordon, David Bartol

Mark S. Gordon

The ground state of disilylsilylene ((SiH3)2Si) is predicted to be the closed-shell (lAin C2 symmetry) state, about 6 kcal/mol below the lowest triplet es, in C2v symmetry) at the MP4/6-31 0( d) //3-21 0* level of theory. A second triplet with a very small Si-Si-Si angle e A in C2 symmetry) is found to be more than 30 kcal/mol above the ground state. The global minimum on the Si3H6 ground-state surface is predicted to be trisilacyclopropane, 18.3 and 9.7 kcalfmol, respectively, below (SiH3)2Si and SiH3SiH=SiH2•

Ab Initio Calculations On Some C3sih4 Isomers, George W. Schriver, Mark J. Fink, Mark S. Gordon

Mark S. Gordon

Restricted Hartree-Fock ab initio calculations have been performed on various isomers of silacyclobutadiene (C3SiH 4). Geometry optimizations were performed by using various basis sets. Geometric results were similar, but proper description of relative energies required the larger 6-31G* basis. Calculations treating election correlation at the MP2 level were performed on the seven lowest energy structures. These calculations gave similar results. The most stable species found is 2-methylsilacycloprop-2-en-1-ylidene. Silacyclobutadiene is almost 60 kcal mol- 1 less stable, while silatetrahedrane lies a further 32 kcal mol-1 higher in energy. The most stable isomer with normal valence is 2-silabut-1-en-3-yne, 28.2 kcal mol-1 above …

Dynamic Structure Of A Nonaqueous Lamellar Liquid Crystal: Comparison With The Aqueous Case, Stig Friberg, Anthony J.I. Ward, David W. Larsen

Chemistry Faculty Research & Creative Works

The lamellar phase of sodium dodecyl sulfate/decanol/glycerol has been compared to the analogous water-based system. Results of NMR studies of deuteriated alcohol and surfactant showed the bilayer to be more disordered in the nonaqueous case than in the phase made with water. The order profiles of the two systems, however, were of the same form, implying that the same essential packing requirements applied to each case. The overall increase in dynamic disorder observed in the glycerol system is a result of a transversely more disordered bilayer/solvent interface. © 1987, American Chemical Society. All rights reserved.

Polymerization In Nonaqueous Lyotropic Liquid Crystals With A Polymerizable Solvent, Stig Friberg, Chang Sup Wohn, Frances E. Lockwood

Chemistry Faculty Research & Creative Works

Lamellar liquid crystals of lecithin and 2-hydroxyethyl methacrylate (HEMA) were polymerized by using UV radiation. Optical microscopy, infrared spectroscopy, and small-angle X-ray diffraction were used to compare the structure prior to and after polymerization. The lamellar structure was retained after polymerization with increased interlayer spacing. © 1987, American Chemical Society. All rights reserved.

Surface-Enhanced Raman Study Of The Effect Of Ph And Electrode Potential On The Surface Concentrations Of The Electroactive Forms Of Pyridinecarboxaldehydes, Dennis Evans, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Observation Of An Isotope Shift In The Superconducting Transition Temperature Of La1.85Sr0.15Cuo4, Tanya A. Faltens, William K. Ham, Steven W. Keller, Kevin J. Leary, James N. Michaels, Angelica M. Stacy, Hans Conrad Zur Loye, Donald E. Morris, T W. Barbee Iii, Marvin L. Cohen, Cohen S. Hoen, A Zettl

Faculty Publications

An oxygen isotope shift is observed in superconducting La_1.85Sr_0.15CuO₄ when ¹⁸O is substituted partially for ¹⁶O; the superconducting transition temperature T_c is lowered by 0.3 to 1.0 K in different samples. We examine these results using conventioanl phonon-mediated BCS theory and conclude that, for La_1.85Sr_0.15CuO₄, phonons play an important role in the pairing mechanism.

29th Rocky Mountain Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 29th annual meeting of the Rocky Mountain Conference, co-sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy and the Rocky Mountain Chromatography Discussion Group. Held in Denver, Colorado, August 2-6, 1987.

Π Bond Strengths In The Second And Third Periods, Michael W. Schmidt, Phi N. Truong, Mark S. Gordon

Mark S. Gordon

All possible pi bonds formed between the elements C, N, 0, Si, P, and S are considered. The pi bond strengths are estimated by the cis-trans rotation barriers (where possible) and by hydrogenation energies. The ability of these elements to form strong pibonds is in the order 0 > N "" C » S > P > Si. In addition, computed bond lengths and vibrational stretching frequencies are reported for both the singly and doubly bound compounds. The structure of the lowest triplet state of each double-bonded compound is given, along with the singlet-triplet splitting.

Mode Anharmonicity In Molecular Crystals Studied By Piezomodulated Raman Spectrosocpy , K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

Piezomodulated Raman scattering is used to determine the extent of anharmonicity, the phonon-phonon coupling, and the presence of modes involved in the phase transition of 1,2,4,5-tetrabromobenzene. The experiments support earlier theoretical predictions and demonstrate that piezomodulated Raman spectroscopy is an important new approach to the experimental study of lattice dynamics.

Electron Transfer-Oxy Radical Mechanism For Anti-Cancer Agents: 9-Anilinoacridines, Peter Kovacic, James R. Ames, Michael D. Ryan

Chemistry Faculty Research and Publications

A possible mode of action involving electron transfer is advanced for the 9- anilinoacridines. The mechanism entails formation of toxic oxy radicals which destroy the neoplasm. Cyclic voltammetry was performed on iminium type ions derived by protonation of the acridines. Reductions were generally reversible with potentials of about - 0.60 V. Involvement of quinoidal metabolites is also a possibility. The relationship of electrochemical behavior to structure and physiological activity is addressed.