Physical Sciences and Mathematics Commons^™

Proton‐Donor Properties Of Water And Ammonia In Van Der Waals Complexes. Be–H2o And Be–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The potential energy surfaces (PES) of Be–H₂O and Be–NH₃ are studied with particular attention to characterization of proton‐donor properties of water and ammonia. Calculations were performed by means of both supermolecular and intermolecular Møller Plesset perturbation theory. The Be–H₂O PES reveals two van der Waals minima: the C_2v minimum (D_e=176 cm⁻¹, R_e=6.5 bohr), and the H‐bonded minimum (D_e=161 cm⁻¹, R_e=7.5 bohr), separated by a barrier of 43 cm⁻¹ at the T‐shaped configuration. The Be–NH₃ PES reveals only …

Proton‐Donor Properties Of Water And Ammonia In Van Der Waals Complexes. Be–H2o And Be–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Steve Scheiner

The potential energy surfaces (PES) of Be–H₂O and Be–NH₃ are studied with particular attention to characterization of proton‐donor properties of water and ammonia. Calculations were performed by means of both supermolecular and intermolecular Møller Plesset perturbation theory. The Be–H₂O PES reveals two van der Waals minima: the C_2v minimum (D_e=176 cm⁻¹, R_e=6.5 bohr), and the H‐bonded minimum (D_e=161 cm⁻¹, R_e=7.5 bohr), separated by a barrier of 43 cm⁻¹ at the T‐shaped configuration. The Be–NH₃ PES reveals only …

Accounting For Saturation Effects In Pulsed Infrared Laser Excited Photothermal Spectroscopy, Stephen E. Bialkowski

Stephen E. Bialkowski

Equations that relate photothermal lens focal lengths and photothermal deflection angles to saturation absorption coefficients are derived. These equations are derived for two-level absorbers with both homogeneously and inhomogeneously broadened transitions. Initial and time-dependent photothermal lens signals are calculated. Equations describing the zero-time signals are exact to within the simplifying assumptions of the derivation, while the time-dependent signals are approximate. The approximation is performed by the use of a finite series of Gaussian functions to model the temperature change profile distorted by nonlinear absorption. The excitation irradiance-dependent signal behavior for rectangular and exponential excitation pulse time profiles for homogeneously and …

In Situ Dielectric Monitoring And Kinetic Analysis Of Phase Separation, Theodore Joon Kim

Dissertations, Theses, and Masters Projects

No abstract provided.

Dielectric Relaxation In Controlled Pore Glass, David Brian Faddis

Dissertations, Theses, and Masters Projects

No abstract provided.

Cross-Linking Additives As Smoke Suppressants For Poly(Vinyl Chloride), Steven Alfred Terranova

Dissertations, Theses, and Masters Projects

No abstract provided.

Pairwise And Many-Body Contributions To Interaction Potentials In He(N) Clusters, Carol A. Parish, Clifford E. Dykstra

Chemistry Faculty Publications

High level ab initio calculations have been carried out to assess the pairwise additivity of potentials in the attractive or well regions of the potential surfaces of clusters of helium atoms. A large basis set was employed and calculations were done at the Brueckner orbital coupled cluster level. Differences between calculated potentials for several interacting atoms and the corresponding summed pair potentials reveal the three‐body and certain higher order contributions to the interaction strengths. Attraction between rare gas atoms develops from dispersion, and so helium clusters provide the most workable systems for analyzing nonadditivity of dispersion. The results indicate that …

Electrochemical Studies Of Swelling And Shrinking Of Clay Films, Jia Du

Master's Theses

No abstract provided.

Reactions Of 1-Triptycyl Carbinol And Bis-(1-Triptycyl)-Carbinol, Bryce Arthur Milleville

Master's Theses

No abstract provided.

Rapid Reduction Of Nitrate Ion In Rain Water, David M. Chittenden Ii

Journal of the Arkansas Academy of Science

No abstract provided.

Suppression Of The Oxidation Of S(Iv) In Rainwater, David M. Chittenden Ii

Journal of the Arkansas Academy of Science

No abstract provided.

Microscale Preparation Of Pyrocatechol: The Use Of Sodium Percarbonate In The Dakin Reaction, T. Evans Yamazaki, Dominic T.C. Yang

Journal of the Arkansas Academy of Science

No abstract provided.

Telomere Processing In Euplotes, Joris Robert Vermeesch, Dewight Williams, Carolyn M. Price

Chemistry Department: Faculty Publications

In Euplotes crassus millions of telomeres are synthesized during the sexual phase of the life cycle. Since these newly synthesized telomeres are longer than normal macronuclear telomeres, they must be trimmed to the mature size. We have examined the timing and mechanism of this trimming step. We have shown that a sudden decrease in telomere length takes place at a specific time during macronuclear development. The decrease in telomere length is not caused by incomplete replication of the most terminal DNA sequences; rather it is the result of an active processing event that occurs independently of DNA replication. The developmentally …

A Study Of Molecular Order And Motion In Nematic Liquid Crystal Mixtures, Jon Michael Goetz

Dissertations, Theses, and Masters Projects

Materials which flow like fluids, but possess anisotropic properties like molecular crystals, are called 'liquid crystals'. Studies of liquid crystals contribute to our understanding of how molecular orientation influences macroscopic properties. This thesis presents experimental and theoretical investigations of molecular order and dynamics in nematic liquid crystal systems. First, deuterium nuclear magnetic resonance is used to determine the degree of orientational order of both components of a liquid crystal mixture simultaneously. The temperature dependence of the four order parameters is interpreted using a newly developed mean field theory of nematic binary mixtures composed of biaxial molecules. Next, mean field theory …

Synthesis Of Boron-Substituted Isoxazolidines By Reaction Of Nitrones With Alkenyl Boronate Esters, Kevin P. Gwaltney

Dissertations, Theses, and Masters Projects

No abstract provided.

Remote Sensing Of Vehicle Emissions, Case Study: Thessaloniki, Greece (Presentation), Kostas Nikolaou, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

Dna Replication In Chloroplasts, Sabine Heinhorst, Gordon C. Cannon

Faculty Publications

Chloroplasts contain multiple copies of a DNA molecule (the plastome) that encodes many of the gene products required to perform photosynthesis. The plastome is replicated by nuclear-encoded proteins and its copy number seems to be highly regulated by the cell in a tissue-specific and developmental manner. Our understanding of the biochemical mechanism by which the plastome is replicated and the molecular basis for its regulation is limited. In this commentary we review our present understanding of chloroplast DNA replication and examine current efforts to elucidate its mechanism at a molecular level.

Β-Homopipitzolone, Ezequiel Huipe Nava, V. A. Igonin, Sergey V. Lindeman, Yuri T. Struchkov, V. Mendoza, G. Garcia, J. A. Guzman

Chemistry Faculty Research and Publications

The structure of β-homopipitzolone (one of the two isomers of an intermediate product in the homocedrole synthesis) has been unequivocally established as 1 O-hydroxy-2,6,9-trimetbyltricyclo[6.3.1.0^1,6] dodeca-9-ene-5, II, 12-trione with relative IR,2R,6R,8S configuration.

Structure Of 2-Methyl-5,6,7-Triphenyl-6,7-Dihydropyrazolo[2,3-A]Pyrimidine, Sergey V. Lindeman, Yuri T. Struchkov, O. V. Shishkin, S. M. Desenko, V. V. Lipson, V. D. Orlov

Chemistry Faculty Research and Publications

C₂₅H₂₁N₃, M_r = 363.46, monoclinic, P2₁/n, a = 9.245 (2), b = 23.502 (5), c = 9.340 (2) Å, β= 103.50(3)°, V=1973.3(2) ų, Z=4, D_x= 1.220 (2) g cm^-3, λ (Mo Kα )= 0.71069 Å, μ = 0.068 cm^-1, F(000) = 768, T= 292 K, R = 0.091 for 1442 unique observed reflections. The dihydropyrimidine ring adopts a distorted sofa conformation. The aryl substituents on the saturated C atoms have an axial orientation.

High-Energy Behavior Of The Double Photoionization Of Helium From 2 To 12 Kev, Jon C. Levin, Ivan A. Sellin, B. M. Johnson, Dennis W. Lindle, R. D. Miller, Y. Azuma, H. G. Berry, D.-H. Lee, N. Berrah

Chemistry and Biochemistry Faculty Research

We report the ratio of double-to-single photoionization of He at several photon energies from 2 to 12 keV. By time-of-Aight methods, we find a ratio consistent with an asymptote at 1.5%±0.2%, essentially reached by h v≈4 keV. Fair agreement is obtained with older shake calculations of Byron and Joachain [Phys. Rev. 164, 1 (1967)], of Aberg [Phys. Rev. A 2, 1726 (1970)], and with recent many-body perturbation theory (MBPT) of Ishihara, Hino, and McGuire [Phys. Rev. A 44, 6980 (1991)]. The result lies below earlier MPBT calculations by Amusia et al. [J. Phys. B 8 …

Absolute-Convective Instabilities And Their Associated Wave Packets In A Compressible Reacting Mixing Layer, F. Q. Hu, T. L. Jackson, D. G. Lasseigne, C. E. Grosch

Mathematics & Statistics Faculty Publications

In this paper the transition from convective to absolute instability in a reacting compressible mixing layer with finite rate chemistry is examined. The reaction is assumed to be one step, irreversible, and of Arrhenius type. It is shown that absolute instability can exist for moderate heat release without backflow. The effects of the temperature ratio, heat release parameter, Zeldovich number, equivalence ratio, direction of propagation of the disturbances, and the Mach number on the transition value of the velocity ratio are given. The present results are compared to those obtained from the flame sheet model for the temperature using the …

The Oxidation Of Beta-Cyclodextrin Via The Photolysis Of 6-Beta-Cyclodextrin Benzoyl Formate, Heather Alison Creswick

Dissertations, Theses, and Masters Projects

No abstract provided.

Characterization Of Epoxy Resins For Use In The Resin Transfer Molding Process, Christina Kaye Short

Dissertations, Theses, and Masters Projects

No abstract provided.

Participation Of Alkenylboronate Esters In [2+2] Enone-Olefin Photocycloadditions, William Charles Lappenbusch

Dissertations, Theses, and Masters Projects

No abstract provided.

The Synthesis Of N,N-Disubstituted Hydroxylamines Via Rearrangement Reactions Between Trialkylboranes And Nitrones, Stacie M. Cook

Dissertations, Theses, and Masters Projects

No abstract provided.

The Synthesis Of Acetylisophthalic Acid For The Double Capping Of Beta-Cyclodextrin, Shuci Sharma

Dissertations, Theses, and Masters Projects

No abstract provided.

Rotating Biological Contractors As An Effective Removal System Of Waste Petroleum Hydrocarbons From Untreated Wastewaters, John Tanacredi Ph.D., R. C. Cardenas

Faculty Works: CERCOM (1977-2016)

A staged, partially submerged rotating biological disk system was assessed to determine its performance in the reduction of detectable concentrations of polynuclear aromatic hydrocarbons (PAH0 attributable to waste crankcase oils (WCCO) in wastewater effluent. Results indicate that such biological systems for the removal of WCCO aromatic hydrocarbons may be a viable alternative to secondary treatment systems commonly being employed.

Method Development In Coal Extraction, Yunsong Tong

Masters Theses

Organic sulfur compounds in coal should be removed as completely as possible in order to make coal "clean" during its usage. Before any method for coal desulfurization can be investigated, the structure of coal should be known. Soluble substances in coal are more easily analyzed by spectroscopic methods than is the insoluble coal. The goal of this research is to separate soluble organic sulfur compounds from the original coal by pyridine extraction. The weight percentages of the coal extracts obtained from three different coal samples by single step extractions ranged from 8% to 30%. The coal extractability could also be …

Synthesis And Characterization Of Transition Metal Polypyridyl Complexes With A Novel 1,10-Phenanthropteridinedione Ligand, Huakai Huang

Masters Theses

A new alloxazine ligand (1; "Pptd"), produced by the condensation of 1,10-phenanthroline-5,6-dione with 5,6-diamino-1,3-dimethyluracil, and several transition metal complexes containing this ligand, have been synthesized. The Pptd ligands attach to Ru(II), Co(II), or Re(I) metal centers through the phenanthroline linkage to form stable polypyridyl complexes. The spectral and the electrochemical characterization of Pptd complexes of Ru(II), Co(II), and Re(I) is presented.

Pptd is capable of being reduced (across the pyrazine nitrogens) by two H-atoms. When coordinated to Ru(II), Pptd forms stable complexes which retain the robust characteristics and electrochemical activity of other Ru(II) polypyridyl species. In addition, Ru(II) complexes of …

Self-Diffusion Studies In Polymer-Solvent Systems By Pulsed-Gradient Spin-Echo Nuclear Magnetic Resonance, R. Allen Waggoner

Doctoral Dissertations

"Pulsed gradient NMR techniques have been used to study self-diffusion in polymer solutions. The systems studied include toluene, cyclohexane, ethylbenzene, chloroform, t-butyl acetate, and methyl ethyl ketone in polystyrene; methyl methacrylate in poly(methyl methacrylate); poly(ethylene oxide) in water; and water in biological tissue. The polymer diffusion data are evaluated in terms of scaling theory as they relate to the scaling of the polymer diffusion coefficient with molecular weight. The solvent diffusion data are evaluated with kinetic and free-volume theories. In addition a relatively simple dependence of diffusion coefficient on polymer volume fraction is derived from free-volume theory. The solvent diffusion …