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Articles 26581 - 26610 of 34733

Full-Text Articles in Physical Sciences and Mathematics

Sulfoxides As An Intramolecular Sulfenylating Agent For Indoles And Diverse Applications Of The Sulfide-Sulfoxide Redox Cycle In Organic Chemistry, Parag V. Jog Jan 2005

Sulfoxides As An Intramolecular Sulfenylating Agent For Indoles And Diverse Applications Of The Sulfide-Sulfoxide Redox Cycle In Organic Chemistry, Parag V. Jog

Dissertations, Master's Theses and Master's Reports - Open

This dissertation involves study of various aspects of sulfoxide chemistry. Specifically designed t-butyl and propanenitrile sulfoxides tethered to indole-2-carboxamide were used as a source of intramolecular sulfenylating agents to synthesize novel indolo[3,2-b]-1-5-benzothiazepinones which are structurally analogous to the other biologically active benzothiazepinones. This study reveals that the intramolecular cyclization of sulfoxide follows an electrophilic sulfenylation (Sulfoxide Electrophilic Sulfenylation, SES) reaction pathway. Evidence of the absence of sulfenic acid as a transient reactive intermediate in such intramolecular cyclization is also provided.

In another study, sulfoxide was used as a “protecting group” of thioether to synthesize 8-membered, indole substituted, thiazocine-2-acetic acid derivative …


Nonlinear Dynamics Of Piezoelectric High Displacement Actuators In Cantilever Mode, Timothy Usher, Alec Sim Jan 2005

Nonlinear Dynamics Of Piezoelectric High Displacement Actuators In Cantilever Mode, Timothy Usher, Alec Sim

Physics Faculty Publications

Experimental results of the nonlinear dynamic response of a piezoelectric high displacement actuator known as thin-layer composite unimorph ferroelectric driver and sensor were compared to a theoretical model, which utilizes the multiple scales method to connect the effective spring constant to higher-order stiffness constants c4 of the piezoelectric layer. This type of actuator has prestress gradients resulting from the manufacturing process that have been reported to play an important role in enhanced actuation. A value of c4=−4.7x1020 N/m2 was obtained for the higher-order lead zirconate titanate (PZT) stiffness coefficient, which is higher than other published results …


Mass Spectrometric And Computational Study Of Snpb In The Gas Phase, G Gigli, Giovanni Meloni, M Carrozzino Jan 2005

Mass Spectrometric And Computational Study Of Snpb In The Gas Phase, G Gigli, Giovanni Meloni, M Carrozzino

Chemistry Faculty Publications

The SnPb molecule has been identified in a Knudsen effusion mass spectrometry experiment. The direct dissociation reaction and two isomolecular exchange reactions involving the Sn(2) and Pb(2) molecules have been studied, in the 1426-1705 K range of temperatures, using both second and third law procedures. The D(degree)0(SnPb,g) has been derived, for the first time, as (122.6+/-4.0) kJ mol(-1). Density functional and ab initio calculations up to the coupled clusters level of theory were also performed. In addition, the anion dissociation energy D(degree)0(SnPb(-),g) of (179.2+/-4.2) kJ mol(-1) was determined using the D(degree)0(SnPb,g) mass spectrometric value derived in this investigation and literature …


Gallium Oxide And Dioxide: Investigation Of The Ground And Low-Lying Electronic States Via Anion Photoelectron Spectroscopy, Giovanni Meloni, S M. Sheehan, D M. Neumark Jan 2005

Gallium Oxide And Dioxide: Investigation Of The Ground And Low-Lying Electronic States Via Anion Photoelectron Spectroscopy, Giovanni Meloni, S M. Sheehan, D M. Neumark

Chemistry Faculty Publications

The GaO and GaO2 molecules were investigated using negative ion photoelectron spectroscopy. All the photoelectron spectra showed vibrationally resolved progressions. With the aid of electronic structure calculations and Franck-Condon spectral simulations, different molecular parameters and energetics of GaO-/GaO and GaO2-/GaO2 were determined, including the electron affinity of GaO, the vibrational frequency of GaO-, and the term energy, spin-orbit splitting, and vibrational frequency for the first excited A 2PiOmega state of GaO. The GaO2- photoelectron spectra comprised three bands assigned as transitions from the linear X 1Sigma(g)+ ground state of GaO2- to three linear neutral states: the A 2Pi(g), B 2Pi(u), …


Simulation Of Electronic And Geometric Degrees Of Freedom Using A Kink-Based Path Integral Formulation: Application To Molecular Systems, Randall W. Hall Jan 2005

Simulation Of Electronic And Geometric Degrees Of Freedom Using A Kink-Based Path Integral Formulation: Application To Molecular Systems, Randall W. Hall

Collected Faculty and Staff Scholarship

A kink-based path integral method, previously applied to atomic systems, is modified and used to study molecular systems. The method allows the simultaneous evolution of atomic and electronic degrees of freedom. Results for CH4, NH3, and H2O demonstrate this method to be accurate for both geometries and energies. Comparison with DFT and MP2 level calculations show the path integral approach to produce energies in close agreement with MP2 energies and geometries in close agreement with both DFT and MP2 results.


Mathematical Modeling Of The Hypothalamic-Pituitary-Adrenal System Activity, Zeljko D. Cupic Jan 2005

Mathematical Modeling Of The Hypothalamic-Pituitary-Adrenal System Activity, Zeljko D. Cupic

Zeljko D Cupic

No abstract provided.


Involvement Of Porin N,N-Dicyclohexylcarbodiimide-Reactive Domain In Hexokinase Binding To The Outer Mitochondrial Membrane, Philadelphia University Jan 2005

Involvement Of Porin N,N-Dicyclohexylcarbodiimide-Reactive Domain In Hexokinase Binding To The Outer Mitochondrial Membrane, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Modeling And Analysis Of An On Line Fms, Philadelphia University Jan 2005

Modeling And Analysis Of An On Line Fms, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Novel Technique To Control The Premature Infant Incubator System Using Ann, Philadelphia University Jan 2005

Novel Technique To Control The Premature Infant Incubator System Using Ann, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Rules Of Ownership Of Artificial Persons Of Intellectual Property Rights -Comparative Study Between Jordanian, & French Laws-, Philadelphia University Jan 2005

Rules Of Ownership Of Artificial Persons Of Intellectual Property Rights -Comparative Study Between Jordanian, & French Laws-, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


The Role Of Knowledge Management In Enhancing The Competitiveness Of Small And Medium-Sized Enterprises (Smes), Philadelphia University Jan 2005

The Role Of Knowledge Management In Enhancing The Competitiveness Of Small And Medium-Sized Enterprises (Smes), Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Solar Cooker Utilizing Satellite Dish Technology, Philadelphia University Jan 2005

Solar Cooker Utilizing Satellite Dish Technology, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Evaluation Technique In The Spi-Calculus For Cryptographic Protocols, Philadelphia University Jan 2005

Evaluation Technique In The Spi-Calculus For Cryptographic Protocols, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


The State Of Engineering Postgraduate Studies In Iraqi Universities, Philadelphia University Jan 2005

The State Of Engineering Postgraduate Studies In Iraqi Universities, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


An Approach Of Web Services Quality Attributes Specification, Philadelphia University Jan 2005

An Approach Of Web Services Quality Attributes Specification, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Mechanism Of Structural Transformation In Bismuth Titanate, Sudhanshu Mallick, Keith J. Bowman, Alexander H. King Jan 2005

Mechanism Of Structural Transformation In Bismuth Titanate, Sudhanshu Mallick, Keith J. Bowman, Alexander H. King

Alexander H. King

Sodium-doped bismuth titanate undergoes a transformation from Bi4Ti3O12 to Na0.5Bi4.5Ti4O15 on heating in air at temperatures exceeding 800 °C. This transformation proceeds through the intermediate Na0.5Bi8.5Ti7O27 structure which is an intergrowth phase of the two. High-resolution transmission electron microscopy was used to study this transformation. From the Moiré pattern that was obtained, the crystallographic orientation of the transformation front has been determined and a mechanism is proposed for this structural transformation.


Photothermal Reshaping Of Prismatic Au Nanoparticles In Periodic Monolayer Arrays By Femtosecond Laser Pulses, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed Jan 2005

Photothermal Reshaping Of Prismatic Au Nanoparticles In Periodic Monolayer Arrays By Femtosecond Laser Pulses, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed

Wenyu Huang

Prismatic goldnanoparticles in the periodic monolayer arrays prepared with nanosphere lithography technique can be reshaped with femtosecond laser pulses at different powers and wavelengths. As the power density of 400 nm femtosecond laser increases, the prismatic particle tips begin to round and the overall particle shape changes from a prism to a sphere with a tripodal intermediate. The formation of the tip-rounded nanoprisms is probably due to the dewetting properties of gold on quartz surface and the low melting temperature at the tips. The formation of the tripodal nanoparticles is attributed to the inhomogeneous heating and lattice rearrangement of the …


The Optically Detected Coherent Lattice Oscillations In Silver And Gold Monolayer Periodic Nanoprism Arrays:  The Effect Of Interparticle Coupling, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed Jan 2005

The Optically Detected Coherent Lattice Oscillations In Silver And Gold Monolayer Periodic Nanoprism Arrays:  The Effect Of Interparticle Coupling, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed

Wenyu Huang

Using femtosecond transient spectroscopy, we studied the optically detected laser-induced coherent phonon oscillation of monolayers of periodic arrays of prismatic-shaped silver and gold nanoparticles, assembled by using the technique of nanosphere lithography. In this method, the same size of polystyrene sphere and the same vacuum conditions are used. Under these circumstances, the gold nanoprisms formed are found to have sharper tips than the corresponding silver nanoprisms. For both gold and silver nanoparticles, the surface plasmon absorption maximum is found to depend linearly on size. The coherent lattice oscillation periods are also found to depend linearly on size. However, although the …


Dislocation-Indenter Interaction In Nanoindentation, M. Ravi Shankar, Alexander H. King, Srinivasan Chandrasekar Jan 2005

Dislocation-Indenter Interaction In Nanoindentation, M. Ravi Shankar, Alexander H. King, Srinivasan Chandrasekar

Alexander H. King

A formulation of dislocation-indenter interaction in two-dimensional, isotropic elasticity is presented. A significant dislocation-indenter interaction is predicted when dislocations are nucleated very close to the indenter. This interaction is expected to have an important influence on dislocation motion and multiplication. Upon nucleation close to the indenter, the dislocations are shown to modify the load, load distribution, and moment acting on the indenter. This effect is seen to vary with the indentation contact length. Further away from the indenter, the indenter-dislocation interaction is shown to be negligible.


2,2':6',2"-Terpyridine 1,1"-Dioxide Dihydrate, Kraig A. Wheeler, Scott E. Mckay, Robert W. Lashlee Iii Jan 2005

2,2':6',2"-Terpyridine 1,1"-Dioxide Dihydrate, Kraig A. Wheeler, Scott E. Mckay, Robert W. Lashlee Iii

Kraig A. Wheeler

No abstract provided.


Vibrational Dependence Of The H2–H2 C6 Coefficients, Robert Hinde Jan 2005

Vibrational Dependence Of The H2–H2 C6 Coefficients, Robert Hinde

Robert Hinde

We use the sum-over-states formalism to compute the imaginary-frequency dipole polarizabilities for H2, as a function of the H–H bond length, at the full configuration interaction level of theory using atom-centered d-aug-cc-pVQZ basis sets. From these polarizabilities, we obtain isotropic and anisotropic C6 dispersion coefficients for a pair of H2 molecules as functions of the two molecules’ bond lengths.


Development Of Fluorapatite As A Waste Form: Final Report #280204-1, Boris E. Burakov Jan 2005

Development Of Fluorapatite As A Waste Form: Final Report #280204-1, Boris E. Burakov

Separations Campaign (TRP)

In the framework of Agreement #280204 (first year) it was necessary to review methods of apatite synthesis; identify optimal procedure of precursor preparation; obtain and study first fluorapatite samples. Although, some apatite-based ceramics were successfully synthesized using co-precipitated precursors and sintering method, there are still a lot of uncertainties related to optimal apatite doping with different radionuclides and non-radioactive elements. It is necessary to provide complete incorporation of waste elements into apatite crystalline structure avoiding formation of separate phases of radionuclides. Also, it is important to note that real waste streams might contain radionuclides with essentially different chemical features such …


Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski Jan 2005

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski

Fuels Campaign (TRP)

This project examines inert fuels containing ZrO2 and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO2. Reactor physics calculations are used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of 239Pu. Ceramics are synthesized and characterized based on the reactor physics results. The solubility of the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, are investigated in a manner to provide thermodynamic data necessary for …


A Regularized And Renormalized Electrostatic Coupling Hamiltonian For Hybrid Quantum-Mechanical–Molecular-Mechanical Calculations, Pradip K. Biswas, Valentin Gogonea Jan 2005

A Regularized And Renormalized Electrostatic Coupling Hamiltonian For Hybrid Quantum-Mechanical–Molecular-Mechanical Calculations, Pradip K. Biswas, Valentin Gogonea

Chemistry Faculty Publications

We describe a regularized and renormalized electrostatic coupling Hamiltonian for hybrid quantum-mechanical (QM)–molecular-mechanical (MM) calculations. To remedy the nonphysical QM/MM Coulomb interaction at short distances arising from a point electrostatic potential (ESP) charge of the MM atom and also to accommodate the effect of polarized MM atom in the coupling Hamiltonian, we propose a partial-wave expansion of the ESP charge and describe the effect of a s-wave expansion, extended over the covalent radius rc, of the MM atom. The resulting potential describes that, at short distances, large scale cancellation of Coulomb interaction arises intrinsically from the localized expansion of the …


Potential Energy Surface Of The Reaction Of Imidazole With Peroxynitrite: Density Functional Theory Study, Valentin Gogonea Jan 2005

Potential Energy Surface Of The Reaction Of Imidazole With Peroxynitrite: Density Functional Theory Study, Valentin Gogonea

Chemistry Faculty Publications

This article presents a theoretical investigation of the reaction mechanism of imidazole nitration by peroxynitrite using density functional theory calculations. Understanding this reaction mechanism will help in elucidating the mechanism of guanine nitration by peroxynitrite, which is one of the assumed chemical pathways for damaging DNA in cells. This work focuses on the analysis of the potential energy surface (PES) for this reaction in the gas phase. Calculations were carried out using Hartree–Fock (HF) and density functional theory (DFT) Hamiltonians with double-zeta basis sets ranging from 6-31G(d) to 6-31++G(d,p), and the triple-zeta basis set 6-311G(d). The computational results reveal that …


Test Of 3He Implanted Target, Caleb Dyer Jan 2005

Test Of 3He Implanted Target, Caleb Dyer

The Corinthian

The proton-proton chains (p-p chains), a series of nuclear reactions were proposed several decades ago as a way in which hydrogen burning can occur in smaller main sequence stars. The 3He + 4He? 7Be reaction determines the path that the p-p chains follow. At present the cross section for this reaction has not been precisely determined. To measure this cross section a 3He target and 4He beam are to be used. 3He exists as a gas so a method to manufacture a solid 3He target was needed. A 3He beam was used …


"Middle Georgia Waters:" Chemical Analysis By Gc&Su Undergraduates, Melanie Mobley, Lance Cramer, Daniel Brooks, Catrena Higginbotham Ph.D Jan 2005

"Middle Georgia Waters:" Chemical Analysis By Gc&Su Undergraduates, Melanie Mobley, Lance Cramer, Daniel Brooks, Catrena Higginbotham Ph.D

The Corinthian

Every living organism on Earth depends on water, many of which must consume liters of fresh water daily. Unfortunately, a readily available source of clean, fresh water is diminishing. Over the years, the fresh water supply has been polluted by biological and chemical sources. The nutrient levels and pesticide chemical contamination of several water locations in the Middle Georgia area were analyzed and monitored by chemistry majors at GC&SU over the past two years.


Stability Of Single Particle Tracers For Differentiating Between Heavy- And Light-Duty Vehicle Emissions, Deborah S. Gross, Alexander R. Barron, Ellen M. Sukovich, Benjamin S. Warren, Julia C. Jarvis, David T. Suess, Kimberly A. Prather Jan 2005

Stability Of Single Particle Tracers For Differentiating Between Heavy- And Light-Duty Vehicle Emissions, Deborah S. Gross, Alexander R. Barron, Ellen M. Sukovich, Benjamin S. Warren, Julia C. Jarvis, David T. Suess, Kimberly A. Prather

Faculty Work

To determine the size and chemical composition of particles derived from on-road vehicle emissions, individual particles were sampledcontinuously with an aerosol time-of-flight mass spectrometer (ATOFMS) at the Caldecott Tunnel in Northern California. In this tunnel, traffic is segregated, such that in theory only light duty vehicle emissions or a mix of heavy- (HDV) and light-duty vehicle (LDV) emissions can be sampled separately. Two studies were carried out, one in November 1997 anda secondin July 2000, time periods with average ambient temperatures of 10–15 and 26–32 1C, respectively, with the instrument operating at ambient outdoor temperatures. Analysis of the chemical composition …


The Edam Project: Mining Atmospheric Aerosol Datasets, Raghu Ramakrishnan, James J. Schauer, Lei Chen, Zheng Huang, Martin M. Shafer, Deborah S. Gross, David R. Musicant Jan 2005

The Edam Project: Mining Atmospheric Aerosol Datasets, Raghu Ramakrishnan, James J. Schauer, Lei Chen, Zheng Huang, Martin M. Shafer, Deborah S. Gross, David R. Musicant

Faculty Work

Data mining has been a very active area of research in the database, machine learning, and mathematical programming communities in recent years. EDAM (Exploratory Data Analysis and Management) is a joint project between researchers in Atmospheric Chemistry and Computer Science at Carleton College and the University of Wisconsin-Madison that aims to develop data mining techniques for advancing the state of the art in analyzing atmospheric aerosol datasets. There is a great need to better understand the sources, dynamics, and compositions of atmospheric aerosols. The traditional approach for particle measurement, which is the collection of bulk samples of particulates on filters, …


Yba2cu3o7 Electro-Magneto-Optic Effects In Ba L2,3 X-Ray Absorption Near Tc, Juana Vivó Acrivos Jan 2005

Yba2cu3o7 Electro-Magneto-Optic Effects In Ba L2,3 X-Ray Absorption Near Tc, Juana Vivó Acrivos

Faculty Publications, Chemistry

The onset of electro magneto-optic effects, observed at the Ba L2,3 edges synchrotron X-ray absorption by a YBa2Cu3O7 single crystal, 10 K above the transition temperature to superconductivity, Tc ~ 92 K is used to identify the role played by the Ba donor layer in the transition to superconductivity in the CuO2 layers. Negative permeability leads to Faraday rotation of the transmitted beam below T = 112 to 56 K for the 22 μm thick single crystal (c-axis orientation of 8π/18 relative to εX-rays) and sharp changes in the density of empty final states lead to zero transmitted radiation in …