Physical Sciences and Mathematics Commons^™

Coarse-Graining Description Of Solid Systems At Nonzero Temperature, Z.-B. Wu, Dennis J. Diestler, Ruqiang Feng, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The quasicontinuum (QC) technique, in which the atomic lattice of a solid is coarse-grained by overlaying it with a finite-element mesh, has been employed previously to treat the quasistatic evolution of defects in materials at zero temperature. It is extended here to nonzero temperature. A coarse-grained Hamiltonian is derived for the nodes of the mesh, which behave as quasiparticles whose interactions are mediated by the underlying (non-nodal) atoms constrained to move in unison with the nodes. Coarse-grained thermophysical properties are computed by means of the Monte Carlo (MC) method. This dynamically constrained QC MC procedure is applied to a simple …

Density Matrix View Of The Double Well Problem, Ronald Lovett

Topics in Quantum Mechanics

No abstract provided.

Heterostructures Of Polymer Photonic Crystal Films, Marc Egen, Rebecca Voss, Bernd Griesebock, Rudolf Zentel, Sergei Romanov, Clivia Sotomayor Torres

Rebecca Cademartiri

This paper describes ways to multilayer opaline films (opaline heterostructures) composed from functional opal layers of spheres with different lattice constants. At first various monodisperse colloidsboth cross-linked and un-cross-linkedwere prepared from methyl methacrylate, methyl α-chloroacrylate, and methyl α-bromoacrylate. These colloids can be crystallized into large, well-oriented opaline films with the help of a “drawing apparatus” by the method of crystallization in a moving meniscus. After annealing, a second opaline film can be crystallized on top of these films and so on. Electron microscopy inspection shows a sharp borderline between the sublayers and no disorder on both sides although the lattice …

Measurement Of Anti-Cancer Agent Methoxyamine In Plasma By Tandem Mass Spectrometry With On-Line Sample Extraction, Shuming Yang, Lili Liu, Stanton L. Gerson, Yan Xu

Chemistry Faculty Publications

In this work, we present the development and validation of a tandem mass spectrometry method for the quantitative determination of methoxyamine (CH3ONH2), a potential new chemotherapeutic agent, in human and mouse plasma. Methoxyamine together with the internal standard (I.S.) methoxyl-D3-amine was directly derivatized in plasma sample with a novel chemical agent 4-(N,N-diethylamino)benzaldehyde. The product solution was injected into an on-line Oasis® HLB extraction column ( mm) for analyte extraction. After the elution of extractives, the derivatized analytes were monitored by the positive-electrospray-ionization mass spectrometry (ESI-MS-MS). The structures of derivatized analytes were elucidated by fragmentation. Quantitation of plasma methoxyamine was carried …

Chemical Analyses For Alcove 8 Niche 3 Tracer Studies, Irene Farnham, Klaus J. Stetzenbach, Amy J. Smiecinski

Publications (YM)

This report details the activities performed under Task 35 of the University and Community College System of Nevada (UCCSN) Cooperative Agreement with the US Department of Energy (DOE). Task 35, titled "Chemical Analyses for Alcove 8 / Niche 3 Tracer Studies", provided for the development of analytical procedures and the analysis of samples from the first phase of tracer testing at Alcove 8 / Niche 3 in the Exploratory Studies Facility (ESF). Two conservative tracers (bromide and pentafluorobenzoic acid) and three FD&C dye tracers (FD&C Blue #1, FD&C Yellow #5, and FD&C Red #40) were analyzed in the seepage samples …

Chemistry & Biochemistry Newsletter, Department Of Chemistry & Biochemistry, South Dakota State University

Chemistry & Biochemistry Newsletter: 2002-2015

Inside:

Page 2 New Graduate Students in Chemistry/Biochemistry

Page 3 and 4 New Faculty

Page 5 Alumni News; Faculty and Staff News; Foundation Donors

Page 6 Recent Faculty Publications

Corrosion And Mass Transport Processes In Carbon Steel Miniature Waste Packages, James Cizdziel, Kaveh Zarrabi, Susan Lestrange, Amy J. Smiecinski

Publications (YM)

In this study, we have systematically investigated corrosion and mass transport processes in carbon steel miniature waste packages (MWP) in dynamic systems (water in, water out) under varying chemical conditions. The MWP were fabricated to have similar configuration to the DOE Spent Nuclear Fuel (SNF) waste package and that individual components to be in scale with each other compare to the SNF waste package. Two MWP configurations were studied: a "bathtub" model and a "flow-through" model. By slowly dripping 4 different solutions (groundwater obtained from well water J-13 located near Yucca Mountain, and J-13 water adjusted to low-pH, high-salinity, and …

Magnetic Storage Device Using Induced Magnetic Reversal Of A Cobalt, Scott Whittenburg

Chemistry Faculty Publications

The effects of the applied field, cell size, and cutting area on the ‘‘seed’’ induced magnetic reversal of a cobalt element array have been studied by a stochastic dynamic micromagnetics code using the Laudau–Lifshitz–Gilbert equation. Three magnetic reversal mechanisms under different magnitudes of the applied field have been investigated by examining the energy profiles. To minimize the effect of the thermal fluctuations on the switching time, an applied field with magnitude around 0.7 or 0.8 T and an element array with cutting area less than 10 nm310 nm are required. By using the smaller cellsize, the switching time and the …

Ab Initio Theoretical Studies Of Potential Energy Surfaces In The Photodissociation Of The Vinyl Radical. I. Ã State Dissociation, Peng Zhang, Stephan Irle, Keiji Morokuma, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

The mechanism of photodissociation of the vinyl radical, C₂H₃ was studied with high-level ab initio methods. Geometry optimizations of stationary points and surface crossing seams were performed with complete active space self-consistent field method. Both internal conversion and intersystem crossing channels which bring the excited vinyl radical down to ground state potential energy surface were identified.

Single-Walled Carbon Nanotube Bundles Intercalated With Semiconductor Nanoparticles, Manashi Nath, Pallavi V. Teredesai, D. V. S. Muthu, A. K. Sood, Chintamani Nagesa Ramachandra Rao

Chemistry Faculty Research & Creative Works

Nanoparticles of CdSe, CdS and ZnSe have been incorporated in the inter-tubular gaps of single-walled carbon nanotube (SWNT) bundles. Electron microscope, X-ray diffraction (XRD), electronic spectroscopy and Raman studies have been employed to characterize these systems. The lengths of the intercalate inside the bundles could be varied by changing the reaction conditions. Electronic absorption and photoluminescence studies from the semiconductor intercalates show the expected blue-shift with respect to the corresponding bulk samples in CdS and ZnS samples. The SWNT lattice is expanded on incorporating CdSe as confirmed by XRD in the low-angle range. The expansion in the lattice is also …

Extensive Regional Atmospheric Hydrocarbon Pollution In The Southwestern United States, Lambert A. Doezema

Chemistry and Biochemistry Faculty Works

Light alkane hydrocarbons are present in major quantities in the near-surface atmosphere of Texas, Oklahoma, and Kansas during both autumn and spring seasons. In spring 2002, maximum mixing ratios of ethane [34 parts per 109 by volume (ppbv)], propane (20 ppbv), and n-butane (13 ppbv) were observed in north-central Texas. The elevated alkane mixing ratios are attributed to emissions from the oil and natural gas industry. Measured alkyl nitrate mixing ratios were comparable to urban smog values, indicating active photochemistry in the presence of nitrogen oxides, and therefore with abundant formation of tropospheric ozone. We estimate that 4-6 teragrams of …

Targeting The Transcriptional Machinery With Unique Artificial Transcriptional Activators, Brian Brennan, Zhiqian Wu, Garrette Belanger, Jenifer Lum, Aaron Minter, Steven Rowe, Annette Plachetka, Chinmay Majmudar, Anna Mapp

Brian B. Brennan

The link between a growing number of human diseases and misregulation of gene expression has spurred intense interest in artificial transcriptional activators that could be used to restore controlled expression of affected genes. To expand the repertoire of activation domains available for the construction of artificial transcriptional regulators, a selection strategy was used to identify two unique activation domain motifs. These activation domains bear little sequence homology to endogenous counterparts and bind to unique sites within the transcriptional machinery. A comparison with two well-characterized activation domains, VP2 and P201, demonstrated for the first time that functional potency is not solely …

Effect Of Polarizability Of Halide Anions On The Ionic Salvation In Water Clusters, S. Yoo, Y.A. Lei, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Molecular dynamics simulation has been performed to study the effect of the polarizabilities of model anions on the ionic solvation in water clusters. The primary focus is given to the surface versus interior solvation behavior of the anions. To this end, various combinations of polarizable/nonpolarizable water and anion models were considered. Using the nonpolarizable TIP4P water with polarizable Cl₂ and Br₂ models, the Cl₂ is fully solvated inside the (H₂O) ₆₀ cluster, whereas the Br₂ is partially solvated at the surface of the cluster. However, when the polarizability of the Br₂ is turned …

Distributions Of Trace Gases And Aerosols During The Dry Biomass Burning Season In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirchstetter

Chemistry and Physics Faculty Articles

Vertical profiles in the lower troposphere of temperature, relative humidity, sulfur dioxide (SO₂), ozone (O₃), condensation nuclei (CN), and carbon monoxide (CO), and horizontal distributions of twenty gaseous and particulate species, are presented for five regions of southern Africa during the dry biomass burning season of 2000. The regions are the semiarid savannas of northeast South Africa and northern Botswana, the savanna-forest mosaic of coastal Mozambique, the humid savanna of southern Zambia, and the desert of western Namibia. The highest average concentrations of carbon dioxide (CO₂), CO, methane (CH₄), O₃, …

Distributions Of Trace Gases And Aerosols During The Dry Biomass Burning Season In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirschsetter

Chemistry and Biochemistry Faculty Publications

[1] Vertical profiles in the lower troposphere of temperature, relative humidity, sulfur dioxide (SO₂), ozone (O₃), condensation nuclei (CN), and carbon monoxide (CO), and horizontal distributions of twenty gaseous and particulate species, are presented for five regions of southern Africa during the dry biomass burning season of 2000. The regions are the semiarid savannas of northeast South Africa and northern Botswana, the savanna-forest mosaic of coastal Mozambique, the humid savanna of southern Zambia, and the desert of western Namibia. The highest average concentrations of carbon dioxide (CO₂), CO, methane (CH₄), O_{3 …}

Pressure-Induced Insulating State In An Organic Superconductor, Gary L. Gard, Javid Mohtasham, J. A. Schlueter, C. Pfleiderer, J. Wosnitza, J. Hagel

Chemistry Faculty Publications and Presentations

The electronic-transport properties of the quasi-two-dimensional organic superconductor β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃, where BEDT-TTF stands for bisethylenedithio-tetrathiafulvalene, have been investigated in magnetic fields up to 15 T and under hydrostatic pressure up to about 14 kbars. Shubnikov–de Haas data reveal a nonmonotonic pressure dependence of the holelike Fermi surface, a roughly linear increase of the electron g factor, and an approximately linear decrease of the cyclotron effective mass. By assuming that the latter reflects the pressure-induced reduction of the superconducting coupling parameter λ the rapid reduction of the superconducting transition temperature Tc(p) can be reasonably well described by the modified McMillan equation. Above …

Photodissociation Of The Od Radical At 226 And 243 Nm, Dragana C. Radenovic, Andre J.A. Van Roij, Dmitri A. Chestakov, Andre T.J.B. Eppink, J J. Ter Meulen, David H. Parker, Mark P.J. Van Der Loo, Gerrit G. Groenenboom, Margaret E. Greenslade, Marsha I. Lester

Chemistry

The photodissociation dynamics of state selected OD radicals has been examined at 243 and 226 nm using velocity map imaging to probe the angle–speed distributions of theD(²S) and O(³P₂) products. Both experiment and complementary first principle calculations demonstrate that photodissociation occurs by promotion of OD from high vibrational levels of the ground X ²Π state to the repulsive 1 ²Σ⁻ state.

Afci Quarterly Input – Unlv July Through September, 2003, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Modeling And Control Of Vinyl Chloride In Drinking Water Distribution Systems, Michael Beardsley, Craig D. Adams

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In water distribution systems containing PVC pipe manufactured in the "early era" (prior to 1977), vinyl chloride can leach into drinking water resulting in vinyl chloride concentrations exceeding the 2 μg·L-1 maximum contaminant level. Field testing of dead-end segments of water distribution systems consisting of early-era PVC pipe was conducted to examine their initial intrapipe vinyl chloride monomer (VCM) concentrations based on a Fickian-diffusion-Based leaching model. the experiments showed a wide range of VCM concentrations within early-era PVC pipe ranging from less than 50 to more than 600 mg·kg-1. based on the diffusion modeling approach, a protocol was designed that …

Thermochemistry And Kinetics In Pyrolysis And Oxidation Reaction Of Oxygenate Chlorocarbons, Neopentane, And Ortho-Xylene, Hongyan Sun

Dissertations

Thermochemical properties of chlorinated alcohols, chlorinated hydroperoxides and corresponding alkoxy, hydroxy alkyl radicals, peroxy and hydroperoxy alkyl radicals are determined by ab initlo and density functional calculations for modeling and optimization of complex chemical processes for combustion or incineration of chlorinated hydrocarbons. The entropy and heat capacities from vibrational, translational, and external rotational contributions are calculated by statistical mechanics, and the hindered rotational contributions to S^°₂₉₈ and C_p(T)'s are calculated by using direct integration over energy levels of the internal rotational potentials. The values of ΔH_f^°₂₉₈ are determined using isodesmic reactions …

Synthesis And Application Of Novel Chiral Ionic Liquids Derived From Alpha-Pinene, Yun Wang

Theses

Two new chiral ionic liquids of oxazolinium cations derived from a-pinene: 9,9-Dimethyl-4-propenyl-5-propyl-3 -oxa-5-azonia-tricyclo [6.1.1.0 ^2,6] dec-4-ene tetrafluoro borate ([ChIPOZ] [BF₄]) and 9,9-Dimethyl-4-propenyl-5-propyl-3-oxa-5-azonia-tricyclo [6.1.1.0 ^2,6] dec-4-ene hexafluoro phosphate ([ChIPOZ][PF₆]). Both these chiral ionic liquids have been applied in enantiomeric copper-catalyzed 1,4-addition reactions with diethyl zinc. The enantiomeric excess for product using [ChIPOZ][BF₄] is above 70% and for [ChIPOZ][PF₆] is above 30%. Chiral ionic liquids worked as phase transfer catalysts In this reaction.

α-Pinene was used as the "chiral pool" in the synthesis of amino alcohol through a two-step reaction, followed by …

Growth Of Well-Defined Zno Microparticles By Hydroxide Ion, Ruth Mcbride, Declan Mccormack, John Kelly

Articles

The morphology of the microcrystalline zinc oxide formed by reaction of zinc salts with sodium hydroxide depends critically on the reaction conditions. To understand this, the nature of the solid product has been probed by scanning electron microcopy (SEM) and X-ray diffraction (XRD) and the concentration of zinc remaining in the solution has been determined at regular intervals throughout the reaction. Two general preparative procedures have been followed. The first, which involves simply heating an aqueous solution containing Zn(NO3)2 (0.025 M) and sodium hydroxide (0.375 M) to 101 uC and maintaining it at that temperature for periods of up to …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Fourth Quarterly Report 06/01/2003-08/30/2003, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the TRP proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with only very sparse experimental data. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Task V: Annual Report -Phase Ii 09/01/2002-08/30/2003, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the TRP proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with only very sparse experimental data. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high …

Structural Requirements For Expression Of Factor Va Activity, Michael Kalafatis, Daniel O. Beck, Kenneth G. Mann

Chemistry Faculty Publications

Thrombin activated factor Va (factor VIIa, residues 1-709 and 1546-2196) has an apparent dissociation constant (Kd,app) for factor Xa within prothrombinase of approximately 0.5 nM. A protease (NN) purified from the venom of the snake Naja nigricollis nigricollis, cleaves human factor V at Asp697, Asp1509, and Asp1514 to produce a molecule (factor VNN) that is composed of a Mr 100,000 heavy chain (amino acid residues 1-696) and a Mr 80,000 light chain (amino acid residues 1509/1514-2196). Factor VNN, has a Kd,app for factor Xa of 4 nm and reduced clotting activity. Cleavage of factor VIIa by NN at Asp697 results …

An Electrochemical Prediction Method For Caustic Scc Of Fe-Cr-Ni Alloy, Chun-Bo Huang, Zhan-Peng Lv, Wu Yang

Journal of Electrochemistry

Stress corrosion cracking (SCC) of Fe_Cr_Ni alloy (alloy 800 M) in hot concentrated caustic solution was investigated by means of tests of C_rings under controlled potentials. The steady dissolution current densities( i st ) of the plate specimens and C_rings polarized potentiostatically were measured. The simplifed steady potentiostatical curves were drawn on the basis of i st . The ratio R PD measured from i st and steady passive current density i p at low potentials ( R PD = i st / i p ) was designed as a polarization dissolution susceptibility parameter. The parameter R PD values of …

Severe Corrosivity And Its Eletrochemical Mechanism Of Seawater In Xiamen Sea Area To Al-Mg Alloys, Le-Yun Lin, Yue-Hong Zhao

Journal of Electrochemistry

The surface layer seawater of different sea areas in China exhibit different corrosivity to Al_Mg alloys according to the experiment results of 16 years exposure in seawater.The seawater in Xiamen sea area possesses severe corrosivity while seawater in Qingdao possesses the mildest corrosivity to Al_Mg alloys with better regularity of corrosion behavior.The present paper illustrates by experiment data that the strongest corrosivity of Xiamen seawater to Al_Mg alloys is owing to the low salinity of the seawater and the “electrolyte effect” come from it.The 16 year corrosion data and corrosion morphology of the typical Al_Mg alloys from full_immersion zone,tide zone …

The Technique Of Rare-Earth Conversion Coatings On Aluminum Alloy, Jun-Tao Wang, Jian-Hua Wu, Guang-Zhang Chen

Journal of Electrochemistry

The orthogonal design was used to screen the film_forming technique on LY12 aluminum alloy using quadrivalent cerium salt, and the corrosion_resistance performance of the coating was studied. The results revealed that: after LY12 aluminum alloy was treated by cerium salt, its pitting potential shifts to positive direction while the corrosion potential slightly decreases, showing that the alloy becomes less sensitive to pitting corrosion was greatly improved, comparable to that after chromate treatment; in addition, by combining the results of electrochemical measurements with surface analysis, the mechanism of corrosion_resistance on the race_earth conversion coating of the aluminum alloy was also discussed.

Synthesis And Electrochemical Properties Of K_2feo_4, Ning Zhou, Shi-Hai Ye, Yong-Long Wang, Xue-Ping Gao, Dong-Feng Lin, Zuo-Xiang Zhou, De-Ying Song

Journal of Electrochemistry

The K 2FeO 4 used for new positive electrode materials was prepared. The primary batteries were used in different concentration of electrolyte and different currents. In 9 mol/L KOH , the capacity was the best. The higher the concentration of electrolyte, the lower the electric potential was. When the batteries discharged in 0.4 C , the capacity reached 521.3 mAh/g. By XRD, we gave the reasonable explanations for the discharge products of K 2FeO 4. Possible mechanism of discharge is discussed.

Corrosion Fatigue And Dynamic Strain Aging Of Duplex Stainless Steel In Aqueous Solution, Chuan-Ming Tseng, I-Hsuang Lo, Wen-Ta Tsai

Journal of Electrochemistry

The corrosion fatigue and dynamic strain aging behaviors of 22%Cr duplex stainless steel (DSS) in sodium chloride solutions were investigated. Austenitic 316L SS and ferrtic 430 SS were also used in this study for a comparison. The experimental results showed that no stress corrosion cracking (SCC) occurred in all these SSs tested in 3.5wt% NaCl solution at 80 ℃. However, dynamic strain aging (DSA) occurred in 316L austenitic SS and 22%Cr DSS during slow strain rate testing (SSRT) in this solution.The occurrence of DSA was dependent on solution temperature,strain rate and the presence of austenitic phase. The corrosion rate of …