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Articles 631 - 660 of 1157

Full-Text Articles in Physical Sciences and Mathematics

Dynamical (E,2e) Studies Of Tetrahydropyran And 1,4-Dioxane, J. D. Builth-Williams, G. Da Silva, L. Chiari, D. B. Jones, Hari Chaluvadi, Don H. Madison, M. J. Brunger Jan 2014

Dynamical (E,2e) Studies Of Tetrahydropyran And 1,4-Dioxane, J. D. Builth-Williams, G. Da Silva, L. Chiari, D. B. Jones, Hari Chaluvadi, Don H. Madison, M. J. Brunger

Physics Faculty Research & Creative Works

We present experimental and theoretical results for the electron-impact ionization of the highest occupied molecular orbitals of tetrahydropyran and 1,4-dioxane. Using an (e,2e) technique in asymmetric coplanar kinematics, angular distributions of the slow ejected electron, with an energy of 20 eV, are measured when incident electrons at 250 eV ionize the target and scatter through an angle of either -10° or -15°. The data are compared with calculations performed at the molecular 3-body distorted wave level. Fair agreement between the theoretical model and the experimental measurements was observed. The similar structures for these targets provide key insights for assessing the …


Advancements In The Design, Synthesis, And Application Of Polybenzimidazoles, Alexander Lanier Gulledge Jan 2014

Advancements In The Design, Synthesis, And Application Of Polybenzimidazoles, Alexander Lanier Gulledge

Theses and Dissertations

The overall goal of the work presented within this thesis is to investigate, understand, and develop structure-property relationships in regards to polymer structure, membrane stability, and device performance. Previous work has shown that material properties such as acid loading, proton conductivity, mechanical integrity, and device performance can be attributed to polymer structure, chemical functionality, and polymer architecture (homo, random, co-polymer etc.). Developing and understanding these relationships is critical to the advancement of fuel cell technology. Within this thesis, several of these relationships are investigated and reported.

Novel polymers and copolymer systems have been developed in this research and have significantly …


Technical Note: Swift - A Fast Semi-Empirical Model For Polar Stratospheric Ozone Loss, M. Rex, S. Kremser, P. Huck, G. Bodeker, I. Wohltmann, M. L. Santee, P. F. Bernath Jan 2014

Technical Note: Swift - A Fast Semi-Empirical Model For Polar Stratospheric Ozone Loss, M. Rex, S. Kremser, P. Huck, G. Bodeker, I. Wohltmann, M. L. Santee, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

An extremely fast model to estimate the degree of stratospheric ozone depletion during polar winters is described. It is based on a set of coupled differential equations that simulate the seasonal evolution of vortex-averaged hydrogen chloride (HCl), nitric acid (HNO3), chlorine nitrate (ClONO2), active forms of chlorine (ClOx = Cl+ClO+2ClOOCl) and ozone (O3) on isentropic levels within the polar vortices. Terms in these equations account for the chemical and physical processes driving the time rate of change of these species. Eight empirical fit coefficients associated with these terms are derived by iteratively fitting the equations …


Middle Atmospheric Changes Caused By The January And March 2012 Solar Proton Events, C. H. Jackman, C. E. Randall, V. L. Harvey, S. Wang, E. L. Fleming, M. López-Puertas, B. Funke, P. F. Bernath Jan 2014

Middle Atmospheric Changes Caused By The January And March 2012 Solar Proton Events, C. H. Jackman, C. E. Randall, V. L. Harvey, S. Wang, E. L. Fleming, M. López-Puertas, B. Funke, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

The recent 23-30 January and 7-11 March 2012 solar proton event (SPE) periods were substantial and caused significant impacts on the middle atmosphere. These were the two largest SPE periods of solar cycle 24 so far. The highly energetic solar protons produced considerable ionization of the neutral atmosphere as well as HOx (H, OH, HO2) and NOx (N, NO, NO2). We compute a NOx production of 1.9 and 2.1 Gigamoles due to these SPE periods in January and March 2012, respectively, which places these SPE periods among the 12 largest in the past 50 yr. Aura Microwave Limb Sounder (MLS) …


The Synthesis Of A Bisbenzothiophene (Bbt) Based Organic Semiconductor With Increased Function And Increased Solubility, Mary England Jan 2014

The Synthesis Of A Bisbenzothiophene (Bbt) Based Organic Semiconductor With Increased Function And Increased Solubility, Mary England

Senior Honors Theses

Organic semiconductors are growing in applications for use in modern technology.1 The main interest in these molecules can be attributed to their low cost (compared to silicon) and their ability to be used on flexible substrates. There are four features that make a good organic semiconductor. First, the molecule should be conjugated, having alternating single and double bonds (lone electron pairs act similarly to double bonds). Secondly, the molecule should be planar, or flat, in shape. Thirdly, the molecule should have a narrow band gap to increase the overall conductivity. Lastly, the molecule should be soluble to ease application. …


The Periodical Winter 2014, Southern Adventist University Jan 2014

The Periodical Winter 2014, Southern Adventist University

the Periodical – Chemistry Department Newsletter

Volume 1, issue 1 of the Periodical includes articles about Rhonda Scott's time as chair of the department, faculty news, a pictorial directory of 2014 graduates, an alumni spotlight, and Chemistry Club news.


Nanoparticles And Polymer Crystallization Kinetics In Hybrid Electronic Devices, Taylor William Wagner Dec 2013

Nanoparticles And Polymer Crystallization Kinetics In Hybrid Electronic Devices, Taylor William Wagner

Master's Theses

Conjugated semi-conducting polymers have become well known for their potential applications in hybrid electronic devices like solar cells, LEDs, and organic displays. These hybrid devices also contain inorganic nanoparticles, which complement the polymer when they are combined into the same layer. Control over the conformation and crystallinity of the polymer is critical for device performance, yet not much is known about the effect that these nanoparticles have on the polymer. Here, zinc oxide nanowire was surface modified with mono-substituted-carboxylic acid tetraphenylporphyrin and dodecanethiol, and introduced to poly(3-hexyl thiophene) in solution. The electron transfer, kinetics, and thermodynamics of this system were …


Kinetic Fractionation Of Gases By Deep Air Convection In Polar Firn, K. Kawamura, J. P. Severinghaus, M. R. Albert, Z. R. Courville Nov 2013

Kinetic Fractionation Of Gases By Deep Air Convection In Polar Firn, K. Kawamura, J. P. Severinghaus, M. R. Albert, Z. R. Courville

Dartmouth Scholarship

A previously unrecognized type of gas fractiona- tion occurs in firn air columns subjected to intense convec- tion. It is a form of kinetic fractionation that depends on the fact that different gases have different molecular diffusivi- ties. Convective mixing continually disturbs diffusive equi- librium, and gases diffuse back toward diffusive equilibrium under the influence of gravity and thermal gradients. In near- surface firn where convection and diffusion compete as gas transport mechanisms, slow-diffusing gases such as krypton (Kr) and xenon (Xe) are more heavily impacted by convec- tion than fast diffusing gases such as nitrogen (N2) and ar- gon …


Thiol-Containing Compounds For The Removal Of Elements From Tissues And Formulations Therefor, Boyd E. Haley, David A. Atwood, Niladri Gupta Nov 2013

Thiol-Containing Compounds For The Removal Of Elements From Tissues And Formulations Therefor, Boyd E. Haley, David A. Atwood, Niladri Gupta

Chemistry Faculty Patents

Methods and pharmaceutical formulations for ameliorating heavy metal toxicity and/or oxidative stress are disclosed, comprising administering pharmaceutically effective amounts of ligands according to the present disclosure.

To see the remainder of the abstract, please download this patent.


P For Discussion: Naming Superheavy Halogen And Noble Elements, Shawn Burdette, Brett Thornton Oct 2013

P For Discussion: Naming Superheavy Halogen And Noble Elements, Shawn Burdette, Brett Thornton

Shawn C. Burdette

No abstract provided.


College Of Science And Mathematics Newsletter, Fall 2013, College Of Science And Mathematics, Wright State University Oct 2013

College Of Science And Mathematics Newsletter, Fall 2013, College Of Science And Mathematics, Wright State University

College of Science and Mathematics Newsletters

This 8 page newsletter discusses various happenings within the College of Science and Mathematics. It begins with a letter from the dean, and continues on with news, events, alumni news, and other community news.


Detection Of Boronic Acids Through Excited-State Intramolecular Proton-Transfer Fluorescence, Matthew R. Aronoff, Brett Vanveller, Ronald T. Raines Oct 2013

Detection Of Boronic Acids Through Excited-State Intramolecular Proton-Transfer Fluorescence, Matthew R. Aronoff, Brett Vanveller, Ronald T. Raines

Brett VanVeller

Boronic acids are versatile reagents for the chemical synthesis of organic molecules. They and other boron-containing compounds can be detected readily by the interruption of the excited-state intramolecular proton transfer (ESIPT) of 10-hydroxybenzo[h]quinolone. This method is highly sensitive and selective, and useful for monitoring synthetic reactions and detecting boron-containing compounds on a solid support.


On The Origin Of Mode- And Bond-Selectivity In Vibrationally Mediated Reactions On Surfaces, Daniel Killelea, Arthur L. Utz Oct 2013

On The Origin Of Mode- And Bond-Selectivity In Vibrationally Mediated Reactions On Surfaces, Daniel Killelea, Arthur L. Utz

Chemistry: Faculty Publications and Other Works

The experimental observations of vibrational mode- and bond-selective chemistry at the gas–surface interface indicate that energy redistribution within the reaction complex is not statistical on the timescale of reaction. Such behavior is a key prerequisite for efforts to use selective vibrational excitation to control chemistry at the technologically important gas–surface interface. This paper outlines a framework for understanding the origin of non-statistical reactivity on surfaces. The model focuses on the kinetic competition between intramolecular vibrational energy redistribution (IVR) within the reaction complex, which in the long-time limit leads to statistical behavior, and quenching, scattering, or desorption processes that restrict the …


Acquisition Of A Polarimeter For Teaching And Research In The Forensic Science And Chemistry Laboratories, Zhaohua Dai Oct 2013

Acquisition Of A Polarimeter For Teaching And Research In The Forensic Science And Chemistry Laboratories, Zhaohua Dai

Cornerstone 3 Reports : Interdisciplinary Informatics

No abstract provided.


Raman Spectroscopy As A Teaching Tool In The Forensic Science And Chemistry Courses, Zhaohua Dai, Elmer-Rico E. Mojico Oct 2013

Raman Spectroscopy As A Teaching Tool In The Forensic Science And Chemistry Courses, Zhaohua Dai, Elmer-Rico E. Mojico

Cornerstone 3 Reports : Interdisciplinary Informatics

No abstract provided.


Acquisition Of An Electrochemical System Instrument For The Development Of Sensors, Elmer-Rico E. Mojico Oct 2013

Acquisition Of An Electrochemical System Instrument For The Development Of Sensors, Elmer-Rico E. Mojico

Cornerstone 1 Reports : Expansion and Enhancements of the Thinkfinity Platform

No abstract provided.


Short, Strong Halogen Bonding In Co-Crystals Of Pyridyl Bis-Urea Macrocycles And Iodoperfluorocarbons, Michael F. Geer, James Mazzuca, Mark D. Smith, Linda S. Shimizu Sep 2013

Short, Strong Halogen Bonding In Co-Crystals Of Pyridyl Bis-Urea Macrocycles And Iodoperfluorocarbons, Michael F. Geer, James Mazzuca, Mark D. Smith, Linda S. Shimizu

Faculty Publications

No abstract provided.


Tuning Supported Catalyst Reactivity With Dendrimer-Templated Pt-Cu Nanoparticles, Natalie N. Hoover, Bethany J. Auten, Bert D. Chandler Sep 2013

Tuning Supported Catalyst Reactivity With Dendrimer-Templated Pt-Cu Nanoparticles, Natalie N. Hoover, Bethany J. Auten, Bert D. Chandler

Bert D Chandler

The effects of particle composition on heterogeneous catalysis were studied using dendrimer-encapsulated nanoparticles (DENs) as precursors to supported Pt-Cu catalysts. Bimetallic Pt-Cu DENs with varying Pt/Cu ratios were prepared in an anaerobic aqueous solution and deposited onto a high-purity commercial alumina support. The dendrimer template was then thermally removed to yield supported nanoparticle catalysts, which were studied with toluene hydrogenation and CO oxidation catalysis as well as infrared spectroscopy of adsorbed CO. Incorporating Cu into Pt nanoparticles had opposite effects on the two test reactions. Cu acted as a mild promoter for CO oxidation catalysis, and the promoting effect was …


Carbon And Oxygen Isotope Study Of Carbonates From Watling's Blue Hole And Blue Hole Five, San Salvador, Bahamas, Elaine D. Flynn Aug 2013

Carbon And Oxygen Isotope Study Of Carbonates From Watling's Blue Hole And Blue Hole Five, San Salvador, Bahamas, Elaine D. Flynn

Mahurin Honors College Capstone Experience/Thesis Projects

Carbonate platforms, such as the Bahamas, formed through deposition and sea level fluctuations. These platforms contain records of rapid interglacial climate change and are useful in studying the impacts of climate change on similar tropical carbonate environments. Blue holes are dissolution lakes that may be beneficial for understanding climate change and anthropogenic impact. A δ13C and δ18O study was conducted on lake sediment core samples from Watling’s Blue Hole and Blue Hole Five on San Salvador Island, Bahamas. These lakes are located in a failed housing development and Watling’s Blue Hole was once part of an …


Hindered Rotation Of Dihydrogen On Synthesized Metal Oxides, George Houston Rouvelas Aug 2013

Hindered Rotation Of Dihydrogen On Synthesized Metal Oxides, George Houston Rouvelas

Masters Theses

A MATLAB program was written to calculate the hindered rotational energies of the hydrogen and deuterium molecules interacting with an anisotropic potential, which may be thought of as a potential energy surface of a metal oxide substrate. It was found that an increase in the hindering potential of the rotation about the azimuthal angle lifted the degeneracy of the j = 1,mj [magnetic quantum number] = plus or minus 1 states. A better understanding of how the rotational states of these systems change as a function of the hindering potential can help to explain features in rotational inelastic neutron scattering …


Biophyschem2011: A Joint Meeting Of The Australian Society For Biophysics And The Raci Physical Chemistry Division Foreword, Adam Trevitt, Jeffrey Reimers, Ronald Clarke, Jamie Vandenberg Jul 2013

Biophyschem2011: A Joint Meeting Of The Australian Society For Biophysics And The Raci Physical Chemistry Division Foreword, Adam Trevitt, Jeffrey Reimers, Ronald Clarke, Jamie Vandenberg

Adam Trevitt

[extract] This Research Front of the Australian Journal of Chemistry is aligned with the BIOPHYSCHEM2011 meeting, a joint conference of the Australian Society for Biophysics and the Physical Chemistry Division of the RACI, which was held at the University of Wollongong from 3 to 6 December 2011. Just shy of 200 delegates made the journey to the Illawarra as these two societies came together for the first time for a national meeting. The idea for this collaboration sprang from the inaugural Australian Biophysical Chemistry Workshop, coordinated by Dr Ron Clarke (U. Sydney) and Dr Tak Kee (U. Adelaide) in 2010. …


College Of Science And Mathematics Newsletter, Summer 2013, College Of Science And Mathematics, Wright State University Jul 2013

College Of Science And Mathematics Newsletter, Summer 2013, College Of Science And Mathematics, Wright State University

College of Science and Mathematics Newsletters

This 8 page newsletter discusses various happenings within the College of Science and Mathematics. It begins with a letter from the dean, and continues on with news, events, alumni news, and other community news.


Exploration Of Aqueous Interfaces And Their Effect On Ion Behavior, Oneka T. Cummings Jul 2013

Exploration Of Aqueous Interfaces And Their Effect On Ion Behavior, Oneka T. Cummings

Doctoral Dissertations

An in-depth understanding of a wide range of physical, chemical, atmospheric and biological processes can only be achieved after the structure and dynamics of interfaces and the interfacial behavior of aqueous species, such as ions, are thoroughly studied and understood. This dissertation describes computational studies conducted to gain a more comprehensive understanding of such interfaces and the behavior of ions in the bulk and interfacial regions of the (1) air/water interface, and (2) alkane/water interfaces.

At the air/water interface the effect of counterion (sodium cations) charge and the influence of ion pairing on anion (chloride) propensity for the air/water interface …


Soil Chemistry: Understanding Phosphorus In The Environment, Paul Milham, Warwick Dougherty, Robert Morrison, Robert Clark, Ronald Smernik, Ashlea Doolette, Lucy Burkitt, Damian Collins, Rebeca Alvarez, Andrew Thomas May 2013

Soil Chemistry: Understanding Phosphorus In The Environment, Paul Milham, Warwick Dougherty, Robert Morrison, Robert Clark, Ronald Smernik, Ashlea Doolette, Lucy Burkitt, Damian Collins, Rebeca Alvarez, Andrew Thomas

Robert Clark

It is an essential ingredient in food production, but poor management means bad news downstream. Understanding the way phosphorus behaves in the environment calls for soil and plant biology, and some new soil chemistry.


Synthesis And Immunological Evaluation Of Type I, Type Ii, And Gamma Delta Nkt Cell Antigens, Brian L. Anderson May 2013

Synthesis And Immunological Evaluation Of Type I, Type Ii, And Gamma Delta Nkt Cell Antigens, Brian L. Anderson

Theses and Dissertations

The purpose of the immune system is to protect our bodies from infection. One way it accomplishes this task is through the presentation of foreign pathogens to NKT cells. After an antigen is presented to the T cell receptor, activated NKT cells quickly release soluble chemical signals, termed chemokines and cytokines, that modulate the response of the immune system. Due to the immunological relevance of NKT cell activation, we developed and synthesised non-natural analogs of immunostimulatory type I, II, and gamma delta NKT cell antigens. The immunological evaluations of these analogs resulted in identification of sulfatide as a gamma delta …


Improving Student Learning Of Organic Chemistry By The Use Of Case Comparisons., Divine-Favour Ekene Anene May 2013

Improving Student Learning Of Organic Chemistry By The Use Of Case Comparisons., Divine-Favour Ekene Anene

College of Arts & Sciences Senior Honors Theses

No abstract provided.


Synthesis And Fading Of Eighteenth-Century Prussian Blue Pigments: A Combined Study By Spectroscopic And Diffractive Techniques Using Laboratory And Synchrotron Radiation Sources, Louise Samain, Fernande Grandjean, Gary J. Long, Pauline Martinetto, Pierre Bordet, Jana Sanyova, David Strivay May 2013

Synthesis And Fading Of Eighteenth-Century Prussian Blue Pigments: A Combined Study By Spectroscopic And Diffractive Techniques Using Laboratory And Synchrotron Radiation Sources, Louise Samain, Fernande Grandjean, Gary J. Long, Pauline Martinetto, Pierre Bordet, Jana Sanyova, David Strivay

Chemistry Faculty Research & Creative Works

Prussian blue, a hydrated iron(III) hexacyanoferrate(II) complex, is a synthetic pigment discovered in Berlin in 1704. Because of both its highly intense color and its low cost, Prussian blue was widely used as a pigment in paintings until the 1970s. The early preparative methods were rapidly recognized as a contributory factor in the fading of the pigment, a fading already known by the mid-eighteenth century. Herein two typical eighteenth-century empirical recipes have been reproduced and the resulting pigment analyzed to better understand the reasons for this fading. X-ray absorption and Mössbauer spectroscopy indicated that the early syntheses lead to Prussian …


College Of Science And Mathematics Newsletter, Spring 2013, College Of Science And Mathematics, Wright State University Apr 2013

College Of Science And Mathematics Newsletter, Spring 2013, College Of Science And Mathematics, Wright State University

College of Science and Mathematics Newsletters

This 8 page newsletter discusses various happenings within the College of Science and Mathematics. It begins with a letter from the dean, and continues on with news, events, alumni news, and other community news.


Ipads In The Science Laboratory: Experience In Designing And Implementing A Paperless Chemistry Laboratory Course, Tiffany Hesser, Pauline Schwartz Apr 2013

Ipads In The Science Laboratory: Experience In Designing And Implementing A Paperless Chemistry Laboratory Course, Tiffany Hesser, Pauline Schwartz

Chemistry and Chemical Engineering Faculty Publications

In the fall of 2012, 20 General Chemistry Honors students at the University of New Haven were issued the new iPad 3 to incorporate these devices both in the classroom and the laboratory. This paper will focus on the integration of the iPad into the laboratory curriculum while creating a paperless experience, an environment where no paper would enter or be used for the laboratory over the course of the year. Specific apps were chosen that would allow for an easy transition of course materials into an electronic format. After a transition period for the students and instructor, the overall …


Use Of Self-Assembled Monolayers To Tailor Surface Properties: From Lubrication To Neuronal Development, Natalie Ann Lafranzo Mar 2013

Use Of Self-Assembled Monolayers To Tailor Surface Properties: From Lubrication To Neuronal Development, Natalie Ann Lafranzo

All Theses and Dissertations (ETDs)

The subsequent work describes advances in modifying the chemical properties of various substrates to tailor the surface properties for specific applications. This is achieved by making use of a molecular assembly known as self-assembled monolayers, or SAMs. SAMs are composed of tightly packed organic molecules that form a well-ordered structure on a substrate. Typically, the head group of the monomer is covalently anchored to the substrate, and monolayer order and self-assembly is achieved through van der Waals interactions between the long alkyl chains of the monomer's tail group. Monolayers containing head groups consisting of thiols, siloxanes, and phosphonates have been …