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Articles 1291 - 1320 of 1828

Full-Text Articles in Chemistry

Identification Of Clay Minerals Of The Eastern Southern Region Of Lake Victoria By Ethylene Glycol And Heat: X-Ray Diffraction And Infrared Spectroscopy Studies, E. H. J. Lugwisha Dec 2011

Identification Of Clay Minerals Of The Eastern Southern Region Of Lake Victoria By Ethylene Glycol And Heat: X-Ray Diffraction And Infrared Spectroscopy Studies, E. H. J. Lugwisha

Tanzania Journal of Science

The effect of glycol and heat on some clay minerals of the eastern southern region of Lake Victoria in Tanzania has been studied. First, Whole Rock Powder mount XRD analysis was carried out at the measuring range 2 # ranging between 2o – 65o. Four non-clay minerals found in samples were Na-feldspar, K-feldspar, pyrope and quartz. Oriented clay mineral XRD analysis diffractograms were developed when the air-dried samples were diffracted in measuring range 2# between 2oo – 32o. Main clay mineral groups found in the samples were kaolinite, illite and montmorillonite. After glycolating the samples, it was evident that kaolinite …


First-Principles Studies On Physical And Chemical Properties Of Nanostructures, Menghao Wu Dec 2011

First-Principles Studies On Physical And Chemical Properties Of Nanostructures, Menghao Wu

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

The physical and chemical properties of decorated graphene and graphene ribbons, single-layer III-V systems, three-dimensional carbon and BN foam, and transition-metal-molecular sandwich nanowires have been investigated by first-principle calculations and their potential applications have been predicted. First, it is shown that zigzag graphene nanoribbons (ZGNRs) can be converted into half metal when their edges are decorated by some chemical functional groups, and the half-metalicity is induced by chemical potential difference between two edges when one edge is decorated by electron-donating group like –OH and the other edge is decorated by electron-accepting group like –F, -NH2, -N(CH3) …


Spectroscopic Methods Of Process Monitoring For Safeguards Of Used Nuclear Fuel Separations, Jamie Lee Warburton Dec 2011

Spectroscopic Methods Of Process Monitoring For Safeguards Of Used Nuclear Fuel Separations, Jamie Lee Warburton

UNLV Theses, Dissertations, Professional Papers, and Capstones

To support the demonstration of a more proliferation-resistant nuclear fuel processing plant, techniques and instrumentation to allow the real-time, online determination of special nuclear material concentrations in-process must be developed. An ideal materials accountability technique for proliferation resistance should provide nondestructive, realtime, on-line information of metal and ligand concentrations in separations streams without perturbing the process. UV-Visible spectroscopy can be adapted for this precise purpose in solvent extraction-based separations.

The primary goal of this project is to understand fundamental URanium EXtraction (UREX) and Plutonium-URanium EXtraction (PUREX) reprocessing chemistry and corresponding UV-Visible spectroscopy for application in process monitoring for safeguards. By …


Optical Properties Of Antiferroelectric Cs2nb4o11: Absorption Spectra And First-Principles Calculations, H. L. Liu, C. R. Huang, G. F. Luo, Wai-Ning Mei Nov 2011

Optical Properties Of Antiferroelectric Cs2nb4o11: Absorption Spectra And First-Principles Calculations, H. L. Liu, C. R. Huang, G. F. Luo, Wai-Ning Mei

Chemistry Faculty Publications

We report a joint experimental and theoretical investigation of the optical properties of Cs2Nb4O11. In room temperature optical absorption spectra, we found a direct gap about 3.5560.05 eV and charge transfer excitations at about 4.96 and 6.08 eV, which are in good agreement with the first-principles calculations. Upon passing through the 165 C antiferroelectric to paraelectric phase transition, the peak energies of two charge transfer bands display almost no temperature dependence, yet they become even broader and exhibit enhanced oscillator strength. We infer this intriguing behavior as the manifestation of Nb cation distortions due to the charge-lattice interaction.


Wetting Properties Induced In Nano-Composite Poss-Ma Polymer Films By Atomic Layer Deposited Oxides, Kyle A. Vasquez, Anita J. Vincent-Johnson, W. Chris Hughes, Brian H. Augustine, Kyoungmi Lee, Gregory N. Parsons, Giovanna Scarel Sep 2011

Wetting Properties Induced In Nano-Composite Poss-Ma Polymer Films By Atomic Layer Deposited Oxides, Kyle A. Vasquez, Anita J. Vincent-Johnson, W. Chris Hughes, Brian H. Augustine, Kyoungmi Lee, Gregory N. Parsons, Giovanna Scarel

Department of Physics and Astronomy - Faculty Scholarship

Due to their unique properties, nano-composite polyhedral oligomeric silsequioxane (POSS) copolymer films are attractive for various applications. Here we show that their natural hydrophobic character can become hydrophilic when the films are modified by a thin oxide layer, up to 8 nm thick, prepared using atomic layer deposition. A proper choice of the deposition temperature and thickness of the oxide layer are required to achieve this goal. Unlike other polymeric systems, a marked transition to a hydrophilic state is observed with oxide layers deposited at increasing temperatures up to the glass transition temperature (∼110 °C) of the POSS copolymer film. …


Neutron Diffraction Of Nabd4: Phase Transition, Rietveld Structure Refinements, And Equation Of State, Guillermo Esparza, Esparza, Patricia Kalita, Andrew Cornelius Aug 2011

Neutron Diffraction Of Nabd4: Phase Transition, Rietveld Structure Refinements, And Equation Of State, Guillermo Esparza, Esparza, Patricia Kalita, Andrew Cornelius

Undergraduate Research Opportunities Program (UROP)

NaBH4 is a hydride with possible applications as a hydrogen storage material for future renewable energy technologies. It’s dehydrogenation properties are enhanced with the mixture of particular catalysts through ball-milling techniques during which local pressures may exceed several GPa’s. It is for this reason that understanding the behavior of pressure induced phase changes of its crystalline unit cell is an area of interest.


Exploring Methods For Earthquake Prediction: The Effects Of Water On The Flow Of Stress-Activated Electric Currents In Igneous Rocks, Aaron M. Jahoda, Friedemann T. Freund Aug 2011

Exploring Methods For Earthquake Prediction: The Effects Of Water On The Flow Of Stress-Activated Electric Currents In Igneous Rocks, Aaron M. Jahoda, Friedemann T. Freund

STAR Program Research Presentations

Much of the devastation and damage of earthquakes can be attributed to the fact that they occur suddenly and without much warning, which limits the ability of people to evacuate and/or properly prepare. One method, however, that might be used to predict seismic events is the generation of electric currents in rocks when stresses are applied. It is observed in this research that the application of direct force onto samples of igneous rock causes the rocks to generate a measurable current, which is attributed to positive-hole charges moving within the oxygen sub-lattice. Because large and changing forces are acted upon …


Bis Photobase Generator, Hoang Tran, Shankar B. Rananavare Aug 2011

Bis Photobase Generator, Hoang Tran, Shankar B. Rananavare

Chemistry Faculty Publications and Presentations

The extension of 193nm technology is desirable due to the magnitude of past investments. Since “optical” advancements are increasingly difficult, there is a strong demand for more sophisticated “smart” resists to increase pattern density. Many studies have proven double pattering can be used for the extension of 193nm lithography. In this study, a new class of two stage photo base generators will be introduced along with the synthetic procedure and molecular characterization. The characterizations for exposure study by NMR have shown typical characteristics to stage decomposition under the exposure of 254nm light as well as promising pitch division. GCMS was …


Synthesis And Characterization Of N- And P- Doped Tin Oxide Nanowires, Hoang Tran, Shankar B. Rananavare Aug 2011

Synthesis And Characterization Of N- And P- Doped Tin Oxide Nanowires, Hoang Tran, Shankar B. Rananavare

Chemistry Faculty Publications and Presentations

Bulk-scale synthetic methods for preparing doped tin oxide (SnO2) nanowires (NWs) are presented. n-and p-doping is achieved through insertion of Antimony and Lithium in tin oxide lattice, respectively. We also present a comparison of the structural and optical properties of SnO2 nanoparticles (NPs), and SnO2 NWs. Both n-type and p- type NWs display a characteristic red shift in their photoluminescence (PL) spectra. Surface plasmons observed in these systems imply high carrier concentrations. These corrosion resistant materials are useful in fabricating ultra-sensitive gas detectors and transparent electronics.


53rd Rocky Mountain Conference On Analytical Chemistry Jul 2011

53rd Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 53rd annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Snowmass, Colorado, July 24-28, 2011.


Communication: Bubbles, Crystals, And Laser-Induced Nucleation, Brandon C. Knott, Jerry L. Larue, Alec M. Wodtke, Michael F. Doherty, Baron Peters May 2011

Communication: Bubbles, Crystals, And Laser-Induced Nucleation, Brandon C. Knott, Jerry L. Larue, Alec M. Wodtke, Michael F. Doherty, Baron Peters

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Short intense laser pulses of visible and infrared light can dramatically accelerate crystal nucleation from transparent solutions; previous studies invoke mechanisms that are only applicable for nucleation of ordered phases or high dielectric phases. However, we show that similar laser pulses induce CO2bubblenucleation in carbonated water. Additionally, in water that is cosupersaturated with argon and glycine, argon bubbles escaping from the water can induce crystal nucleation without a laser. Our findings suggest a possible link between laser-induced nucleation of bubbles and crystals.


Extraction Chromatographic Studies Of Rutherfordium And Dubnium Homologs, Megan E. Bennett May 2011

Extraction Chromatographic Studies Of Rutherfordium And Dubnium Homologs, Megan E. Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Studying the chemistry of transactinide elements does not only allow for these elements to be properly placed in the Periodic Table, but it also permits for the extrapolation of the electronic structure based upon the position of the element in the Periodic Table. In addition it enable for the assessment of the role that relativistic effects play in the chemical behavior of the heaviest elements. An improved understanding of the role of relativistic effects in chemistry of the heaviest elements allows for a better understanding of the fundamentals principles that govern the Periodic Table. In order to investigate the chemistry …


Symmetry-Based Techniques For Qualitative Understanding Of Rovibrational Effects In Spherical-Top Molecular Spectra And Dynamics, Justin Chadwick Mitchell May 2011

Symmetry-Based Techniques For Qualitative Understanding Of Rovibrational Effects In Spherical-Top Molecular Spectra And Dynamics, Justin Chadwick Mitchell

Graduate Theses and Dissertations

Using light to probe the structure of matter is as natural as opening our eyes. Modern physics and chemistry have turned this art into a rich science, measuring the delicate interactions possible at the molecular level.

Perhaps the most commonly used tool in computational spectroscopy is that of matrix diagonalization. While this is invaluable for calculating everything from molecular structure and energy levels to dipole moments and dynamics, the process of numerical diagonalization is an opaque one. This work applies symmetry and semi-classical techniques to elucidate numerical spectral analysis for high-symmetry molecules.

Semi-classical techniques, such as the Potential Energy Surfaces, …


Structure Studies On Lanthanide Technetium Pyrochlores As Prospective Host Phases To Immobilize 99- Technetium And Fission Lanthanides From Effluents Of Reprocessed Used Nuclear Fuels, Thomas Hartmann, Ariana Alaniz Apr 2011

Structure Studies On Lanthanide Technetium Pyrochlores As Prospective Host Phases To Immobilize 99- Technetium And Fission Lanthanides From Effluents Of Reprocessed Used Nuclear Fuels, Thomas Hartmann, Ariana Alaniz

Festival of Communities: UG Symposium (Posters)

We performed a systematic investigation of the incorporation of 99Tc into pyrochlore oxide structures, Ln2Tc2O7, where Ln represents trivalent lanthanide Ln3+ cations, while 99Tc is atetravalent, Tc4+, metal cation. Pyrochlore compounds are high-melting temperature oxides and are recognized for their durability. Our goal in this preliminary study is to characterize and quantify the range of stability of the lanthanum technetium pyrochlore oxide phase. Hereby, powder X-ray diffraction (XRD) and Rietveld analysis were used to determine and characterize the crystalline phase content with high accuracy, and scanning electron microscopy (SEM) was used to characterize the microstructure and homogeneity of the synthesized …


Illicit Drug Analysis By Using Ultra-Short Pulses (Thz Spectroscopy), Canan Karaalioglu Jan 2011

Illicit Drug Analysis By Using Ultra-Short Pulses (Thz Spectroscopy), Canan Karaalioglu

Cornerstone 3 Reports : Interdisciplinary Informatics

No abstract provided.


Climate Change: The Fork At The End Of Now, Micha Tomkiewicz Jan 2011

Climate Change: The Fork At The End Of Now, Micha Tomkiewicz

Publications and Research

There are many books on global warming written entirely from a layman's perspective, and there is a great deal of scientific literature on this subject. But few if any books attempt to bridge the science to those who lack a rigorous background in mathematics, physics and chemistry-but who may be working on careers in environmental science and policy. The new text is designed to introduce the field of global climate change from a scientific perspective-but written in a way that is accessible to students with some or little science background. It reviews the basic principles of climatic thermodynamics and atmospheric …


Band Structures Of Layered Carbon/Boron Nitride Materials With Commensurate Lattices, Christopher C. Wells Jan 2011

Band Structures Of Layered Carbon/Boron Nitride Materials With Commensurate Lattices, Christopher C. Wells

Legacy Theses & Dissertations (2009 - 2024)

The electronic structures of systems consisting of hexagonal boron nitride layers and graphite sheets have been investigated in detail using density functional theory methods with two exchange correlation functions (local density approximation and generalized gradient approximation). The experimental data of graphene, graphite, monolayer hexagonal BN, and hexagonal BN were reproduced well with computational models. The commensurate models used in the investigation were generated by taking the averages of the lattice constants for graphite and h-BN.


Table Of Contents Jan 2011

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.


President's Message, Justin K. Wyatt Jan 2011

President's Message, Justin K. Wyatt

Journal of the South Carolina Academy of Science

No abstract provided.


Scas Officers And Council Members 2010 - 2011 Jan 2011

Scas Officers And Council Members 2010 - 2011

Journal of the South Carolina Academy of Science

No abstract provided.


Glamor- Or How We Achieved A Common Understanding On The Decrease Of Glass Dissolution Kinetics Through International Cooperation, P. Van Iseghem, M. Aertsens, S. Gin, B. Grambow, D. Strachan, P. Mcgrail, G. Wicks, T. Mcmenamin Jan 2011

Glamor- Or How We Achieved A Common Understanding On The Decrease Of Glass Dissolution Kinetics Through International Cooperation, P. Van Iseghem, M. Aertsens, S. Gin, B. Grambow, D. Strachan, P. Mcgrail, G. Wicks, T. Mcmenamin

Journal of the South Carolina Academy of Science

No abstract provided.


Catalytic Carbon Nanostructures And Novel Nanocomposites For Hydrogen Storage, Ashley Stowe, Joseph Teprovich Jr., Douoglas Knight, Matthew Wellons, Ragaiy Zidan Jan 2011

Catalytic Carbon Nanostructures And Novel Nanocomposites For Hydrogen Storage, Ashley Stowe, Joseph Teprovich Jr., Douoglas Knight, Matthew Wellons, Ragaiy Zidan

Journal of the South Carolina Academy of Science

No abstract provided.


Properties And Uses Of Sodium Titanates And Peroxotitanates, David Hobbs Jan 2011

Properties And Uses Of Sodium Titanates And Peroxotitanates, David Hobbs

Journal of the South Carolina Academy of Science

No abstract provided.


Hollow Glass Microspheres As Micro Media For Complex Metal Hydrides Hydrogen Storage Compounds, Rana Mohtadi, Tomoya Matsunaga, Kit Heung, Ray Schumacher, George Wicks Jan 2011

Hollow Glass Microspheres As Micro Media For Complex Metal Hydrides Hydrogen Storage Compounds, Rana Mohtadi, Tomoya Matsunaga, Kit Heung, Ray Schumacher, George Wicks

Journal of the South Carolina Academy of Science

No abstract provided.


Overview Of Hybrid Microwave Technology, Rebecca Schulz, George Wicks, Diane Folz, David Clark Jan 2011

Overview Of Hybrid Microwave Technology, Rebecca Schulz, George Wicks, Diane Folz, David Clark

Journal of the South Carolina Academy of Science

No abstract provided.


Water Quality And Corrosion: Considerations For Nuclear Reactor Systems, Robert L. Sindelar, Greg T. Chandler, John L. Micalonis Jan 2011

Water Quality And Corrosion: Considerations For Nuclear Reactor Systems, Robert L. Sindelar, Greg T. Chandler, John L. Micalonis

Journal of the South Carolina Academy of Science

No abstract provided.


Removal And Sequestration Of Iodide From Alkaline Solutions Using Silver-Doped Carbon Nanotubes, Adrian L. Pishko, Steven M. Serkiz, Apparao M. Rao Jan 2011

Removal And Sequestration Of Iodide From Alkaline Solutions Using Silver-Doped Carbon Nanotubes, Adrian L. Pishko, Steven M. Serkiz, Apparao M. Rao

Journal of the South Carolina Academy of Science

No abstract provided.


Table Of Contents Jan 2011

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.


Scas Officers And Council Members 2010-2011 Jan 2011

Scas Officers And Council Members 2010-2011

Journal of the South Carolina Academy of Science

No abstract provided.


Uranium Distribution In Geochemically Diverse Sediments, Tyler Womble, Wenyi Shu, Kaye Savage Jan 2011

Uranium Distribution In Geochemically Diverse Sediments, Tyler Womble, Wenyi Shu, Kaye Savage

Journal of the South Carolina Academy of Science

No abstract provided.