Chemistry Commons^™

Application Of Electrochemical Process To Recycling Waste Water From Flotation Of Phosphate Ores, Shi-Xin Yu, Wen Sun

Journal of Electrochemistry

The waste water from flotation of phosphate ores can be used to recycling by electrochemical process. The suitable factors of electrochemical process is made by measuring ζ potential and transmittance of the waste water in modified way.

New Esr-Electrochemical Cell Designs For Coaxial Microwave Cavity, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

New cell designs for simultaneous electrochemical (EC) and electron spin resonance (ESR) measurements are reported for coaxial microwave cavity. Adjustable shieldings are introduced so that the working electrode can be much shorter than the full height of the cavity. Besides the traditional helical electrode, the working electrode can be cylinders made from metal plates, metallic meshes or even composite materials. The counter electrode can be placed either inside or outside the cavity. These features make the new designs more flexible than that previously reported. With a nonperforated cylindrical electrode, this cell can be used to determine the standard potential and …

Influence Of Buffers On The Blectrodeposition Of Nickel From A Watts Bath, Can-Zh Gao, Yu-Li Lu, Ru-Tao Liu, Fang Chen, Shu-Ben Li

Journal of Electrochemistry

The electrochemical reactions occurring during the deposition of nickel from Watts bath have been examined using the voltammetric technique. The important reactions taking place at the anode and cathode have been identified. The influence of buffers HAc, H₃BO₃ and NH₄Cl on the rate of nickel deposition was marked in the lower concentration (0.01-0.05 mol/L) of buffers. The reason why buffers make the rate of nickel deposition increase were discussed.

Particulate Sizing And Emission Indices For A Jet Engine Exhaust Sampled At Cruise, Donald E. Hagen, Philip D. Whitefield, J. Paladino, Max B. Trueblood, H. Lilenfeld

Physics Faculty Research & Creative Works

Particle size and emission indices measurements for jet engines, primarily the Rolls Royce RB211 engines on a NASA 757 aircraft are reported. These data were used to estimate the fraction of fuel sulfur that was converted to particulates. These measurements were made in-situ with the sampling aircraft several kilometers behind the source. Some complimentary ground measurements on the same source aircraft and engines are also reported. Significant differences are seen between the ground observations and the in-situ observations, indicating that plume processes are changing the aerosol' s characteristics.

A Comparison Between The Cisd[Tq] Wave Function And Other Highly Correlated Methods: Molecular Geometry And Harmonic Vibrational Frequencies Of Mgh2, Gregory S. Tschumper, Henry F. Schaefer

Chemistry Faculty Research & Creative Works

The linear MgH2 molecule was selected as a model system to compare the total electronic energy (ETOT). equilibrium bond length (re), and vibrational frequency (ωn) predictions from six different configuration interaction (CI) and coupled cluster (CC) methods using three large correlation consistent basis sets. The three CI procedures employed incorporated all single and double substitutions (CISD) as well as all triple and quadruple substitutions (CISDTQ) or limited triple and quadruple substitutions (CISD[TQ]). The remaining three CC schemes included all single and double excitations (CCSD) as well as all triple excitations (CCSDT) or a perturbative approximation of the triple excitations [CCSD(T)]. …

Xanthones As Antimalarial Agents: Binding Interactions Between Heme Analogues And Xanthones, Jane Xu Kelly

Dissertations and Theses

Human falciparum malaria is caused by Plasmodium falciparum parasite, which digests host hemoglobin within its food vacuole, releasing toxic heme. P. falciparum detoxifies free heme to hemozoin by polymerization. This process is believed to be the target of most successful antimalarial drugs, chloroquine and quinine, which are now losing their effectiveness due to the spread of multi-drug resistant strains. Xanthones were recognized in the laboratory of Dr. M. Riscoe (Portland VA Medical Center) to bind to heme, preventing heme polymerization.

This thesis reports a study of the interactions of a potential antimalarial agent, 4,5-dihydroxyxanthone (X2), with heme and tin (IV) …

Molecular Design And Association Constants Of Nizatidine-Guest Complexes, Elizabeth Corbeil

Honors Theses

Nizatidine, N-[2-[[[2-[(dimethylamino)metbyl]-4-thiazolyl]methyl]thio]ethyl]-N'methyl- 2-nitro-l,l-ethenediamine (Axid"), has been investigated for its potential to act as a host in guest-host complexes. Nizatidine binds with the guests through hydrogen bonding and pi-pi interactions. Guest-host studies were conducted using fluorescence quenching, calorimetry, NMR and invisible experiments. The lowest energy conformation of nizatidine is found to be U-shaped through theoretical calculations. Fluorescence experiments indicated that tryptophan and pyridoxine had large association constants. Further studies using calorimetry and NMR techniques concluded that no complexation had occurred. Complexation experiments have been done to find guests that complex with nizatidine. Caffeine, luminol, nicotinamide, phenylalanine, pyridoxine, pyrogallol, and tryptophan were …

Mössbauer-Effect And X-Ray-Absorption Spectral Study Of Sonochemically Prepared Amorphous Iron, Gary J. Long, Dimitri Hautot, Quentin A. Pankhurst, Denis Vandormael, Fernande Grandjean, Jean Pierre Gaspard, Valérie Briois, Taeghwan Hyeon, Kenneth S. Suslick

Chemistry Faculty Research & Creative Works

The Mössbauer spectra of amorphous iron, prepared by using sonochemical methods, exhibit a broad magnetic hyperfine sextet at both 78 and 295 K. The spectra do not change with time if the amorphous iron is not exposed to oxygen or moisture. An analysis of the spectra with the method of Lines and Eibschütz yields average magnetic hyperfine fields of 29.1 and 25.9 T at 78 and 295 K, respectively. The corresponding moments of 1.9_B and 1.7_B agree well with values obtained from earlier magnetization studies and, further, provide strong experimental support for earlier calculations of the magnetic moments …

Particle Concentration Characterization For Jet Engine Emissions Under Cruise Conditions, Jonathan D. Paladino, Philip D. Whitefield, Donald E. Hagen, Alfred R. Hopkins, Max B. Trueblood

Chemistry Faculty Research & Creative Works

Airborne particle measurements during NASA project SUCCESS have shown that particle concentration profiles serve as good indicators of aircraft exhaust plume encounters. During exhaust plume penetrations there is a strong anticorrelation between the ratio of nonvolatile/total particulates and Nitrogen Oxide (NO) concentrations. an increase in fuel sulfur content was found to increase the total particle emission index, while the nonvolatile emission index remained unchanged. the EI's increased by a factor of 2.6 as the fuel sulfur increased from 70 - 700 ppm. the large particle size distribution (200-400 nm) was seen as a good long term indicator of an aircraft …

Quantitative And Stereoisomeric Determination Of Light Biomarkers In Crude Oil And Coal Samples, Alain Berthod, Xiande Wang, Kyung H. Gahm, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Indans and tetralins are considered biological markers (biomarkers). These C9-C11 hydrocarbons are present in small amounts in organic geological samples. Methyl substituted indans or tetralins may possess a stereogenic center (carbon). Thus they can exist as enantiomers and, in the case of disubstituted enties, also as diastereoisomers. The concentrations of 1-methylindan, 1,3-dimethylindan, 1-methyltetralin, and 2-methyltetralin were determined in 16 crude oil samples of different sources and in 14 coal samples of different sources and ranks. Deuterated homologues were synthesized as standards to spike the samples and to assure accurate quantitative analysis. A procedure using HPLC fractionation followed by GC/MS analysis …

Particulate Sizing And Emission Indices For A Jet Engine Exhaust Sampled At Cruise, Donald E. Hagen, Philip D. Whitefield, Jonathan D. Paladino, Max B. Trueblood

Physics Faculty Research & Creative Works

Particle size and emission indices measurements for jet engines, primarily the Rolls Royce RB211 engines on a NASA 757 aircraft are reported. These data were used to estimate the fraction of fuel sulfur that was converted to particulates. These measurements were made in-situ with the sampling aircraft several kilometers behind the source. Some complimentary ground measurements on the same source aircraft and engines are also reported. Significant differences are seen between the ground observations and the in-situ observations, indicating that plume processes are changing the aerosol's characteristics.

Plant-Availability Fractionation Of Nickel For Bioremediation, Jason Henrie

Undergraduate Honors Capstone Projects

The bioremediation of contaminated soils or the biomining of waste tillings has been explored through the use of hyperaccumulating plants such as S. polygaloides which is a nickel hyperaccumulator. However, it is important to discover which soils are well-suited for this type of process by determining the plant-availability of the nickel. By extracting the nickel sequentially with increasing severity it is possible to determine the chemical distribution, or fractionation, of nickel in a soil. One fraction is already suspected to be plant-available and correlates very well with the results of a previous plant-availability study. A calcareous Millville silt loam which …

Site-Directed Mutagenesis Of The Nitrogenase Fe-Protein From Azotobacter Vinelandii, Talmage L. Shill

Undergraduate Honors Capstone Projects

Nitrogen fixation is the chemical reaction of dinitrogen (N₂) being reduced to ammonia (NH₃). This reaction occurs naturally by nitrogen fixing microorganisms which contain the enzyme nitrogenase. The overall reaction is written below.

Determination Of Intracellular Glutathione Concentration Using Monobromobimane, Ryan R. Owens

Undergraduate Honors Capstone Projects

Asbestos is a general term for a group of fibrous silicates. Diseases such as asbestosis, bronchogenic carcinoma, and mesothelioma have been linked to asbestos exposure (1,2). The 1 two classes of asbestos, serpentine and amphibole, are distinguished by differences in structure and chemical composition (3). The amphibole crocidolite contains 27% iron while the serpentine chrysotile contains only 2-3% iron. The higher iron content of crocidolite is proposed to be a contributing factor for a much higher incidence of cancer with crocidolite exposure compared with chrysotile exposure ( 4). Iron mobilized intracellularly from asbestos fibers may participate in the formation of …

Thermal Decomposition Of Cp*Re(Co)(No)No2, Kale Allen Swainston

Undergraduate Honors Capstone Projects

The focus of this work is to examine the thermal reactivity of the Cp*Re(CO)(NO)NO₂ complex. Upon heating with a flame, the orange crystals decompose very rapidly, with a darkening of color and gas production. To investigate this reaction, the decomposition was carefully controlled by heating with N2 gas, and in heated solution. The products obtained from the heated solution were purified using column chromatography, yielding two new interesting compounds, believed to be Cp*ReNO dimers with bridging oxygens.

Structure Of 5-Nitro-2-Tosylaminobenzaldehyde Di(Morpholin-4-Yl)Aminal Complex With Carbon Tetrachloride, V. N. Khrustalev, Sergey V. Lindeman, L. Yu Ukhin, G. I. Orlova, T. N. Gribanova, O. V. Shishkin

Chemistry Faculty Research and Publications

The 5-nitro-2-tosylaminobenzaldehyde di(morpholin-4-yl)aminal forms a stable complex with carbon tetrachloride in the crystal phase. X-ray structural study of this complex indicates an essentially shortened intermolecular contact of 2.89 Å between the oxygen atom of the nitro group and one of the chlorine atom of the CCI₄ molecule. Quantum-chemical calculations by semiempirical AMI method showed that the formation of such complex did not cause considerable decrease of system energy or change of charge distribution in molecules. It was supposed that this associate has van der Waals character.

A Method For The Determination Of Purity Of Pnu-10483 Bulk Drug By Capillary Zone Electrophoresis, Gavin Gibson

Honors Theses

In this investigation, a method was developed for the determination of purity of the drug PNU-10483 using the technique of capillary zone electrophoresis (CZE). CZE was seen as a potential alternative to the formerly used procedure of ion-pair reversed phase highperformance liquid chromatography (HPLC). Nearly five years earlier, a similar study was performed, in which an attempt was made to develop a method that used CZE to determine the purity of bulk drug and the potency of drug tablets. While this development was mostly successful, sporadically unpredictable results reduced the method's overall viability. These outliers were thought to be caused …

Quadratic Electro-Optic Effects In Bacteriorhodopsin: Measurement Of Γ(-Ω;0,0,Ω) In Dried Gelatin Thin Films, Mikio Yamazaki, Jerry Goodisman, Robert R. Birge

Chemistry - All Scholarship

Quadratic electro-optic effects (dc or low frequency Kerr effect) of bacteriorhodopsin dispersed in dried gelatin thin films are examined in the near resonance region at three wavelengths: 633, 647, and 676 nm. The films show relatively large quadratic electro-optic effects compared to other molecular dispersed systems. The purple membrane is fixed within the polymerized gelatin matrix, and we show that the electronic contribution to γ dominates over possible orientational contributions. At 676 nm. the quadratic electro-optic coefficient s₁₁₃₃( - ω;0,0,ω) is 6.7 × 10^-20 m²/V² and the third order nonlinear susceptibility X₁₁₃₃^{(3) …}

Distance Dependence Of Electron Transfer Along Artificial Β-Strands At 298 And 77 K, S. R. L. Fernando, Gennady V. Kozlov, Michael Y. Ogawa

Chemistry Faculty Publications

Photoinduced electron-transfer rate constants were measured for a series of binuclear metallopeptides consisting of a [Ru(bpy)(2)(cmbpy)](2+) electron donor tethered to a Co-III(NH3)(5) electron acceptor by an oligovaline peptide chain (bpy = 2,2'-bipyridine, cmbpy = 4-carboxy-4'-methyl-2,2'-bipyridine). These compounds were shown by H-1 NMR to adopt the conformational properties found within the individual strands of a beta-pleated sheet in both aqueous and methanol solutions. Emission lifetime measurements and HPLC product analysis show that the binuclear donor/acceptor compounds undergo photoinduced electron transfer (ET). The values of k(et) decrease with increasing donor/acceptor distance according to the expression k(et) = k' exp[-beta(r(-)r(0))]. A distance attenuation …

Neutral Dissociation Of Hydrogen Following Photoexcitation Of Hcl At The Chlorine K Edge, D. L. Hansen, J. Cotter, G. R. Fisher, K. T. Leung, R. Martin, Paul Neill, Rupert C. Perera, I. A. Sellin, Marc Simon, Y. Uehara, B. Vanderford, S. B. Whitfield

Chemistry and Biochemistry Faculty Research

Time-of-flight mass spectroscopy was used to study the relaxation dynamics of HCl following photoexcitation in the vicinity of the Cl K edge (~2.8 keV) using monochromatic synchrotron radiation. At the lowest resonant excitation to the 6ơ* antibonding orbital, almost half of the excited molecules decay by emission of a neutral H atom, mostly in coincidence with a highly charged Cln1 ion. The present work demonstrates that neutral-atom emission can be a significant decay channel for excited states with very short lifetimes (1 fs). [S1050-2947(98)03604-X]

Explosive Vapor Generation And Sampling In Conjunction With Ion Mobility Spectrometry, Saeed H. Almeer

Chemistry & Biochemistry Theses & Dissertations

The primary objective of this research is to develop an inexpensive and reliable method to generate vapor pulses of explosives using 2,4,6-trinitrotoluene TNTl for proof of concept. A secondary objective is to demonstrate the use of the vapor generator in various applications keeping in mind potential field scenarios involving explosives. A vapor generator/collector system was developed which gives reproducible pulses of TNT vapors at nanogram levels. The use of this technology was demonstrated in evaluating different surfaces for vapor adsorption of TNT in conjunction with ion mobility spectrometry as the primary analytical tool. Of the materials examined, Teflon was by …

A Cell Cycle-Regulated Adenine Dna Methyltransferase From Caulobacter Crescentus Processively Methylates Gantc Sites On Hemimethylated Dna, Anthony J. Berdis, Irene Lee, James K. Coward, Craig Stephens, Rachel Wright, Lucy Shapiro, Stephen J. Benkovic

Chemistry Faculty Publications

The kinetic properties of an adenine DNA methyltransferase involved in cell cycle regulation of Caulobacter crescentus have been elucidated by using defined unmethylated or hemimethylated DNA (DNAHM) substrates. Catalytic efficiency is significantly enhanced with a DNAHM substrate. Biphasic kinetic behavior during methyl incorporation is observed when unmethylated or DNAHM substrates are used, indicating that a step after chemistry limits enzyme turnover and is most likely the release of enzyme from methylated DNA product. The enzyme is thermally inactivated at 30°C within 20 min; this process is substantially decreased in the presence of saturating concentrations of DNAHM, suggesting that the enzyme …

Characterization And Evaluation Of D-(+)-Tubocurarine Chloride As A Chiral Selector For Capillary Electrophoretic Enantioseparations, Usha B. Nair, Daniel W. Armstrong, Willie L. Hinze

Chemistry Faculty Research & Creative Works

A new macrocyclic of the bis(benzylisoquinoline) alkaloid family, d- (+)-tubocurarine chloride (DTC), has been evaluated as a chiral selector for the separation of optical isomers of organic carboxylates using capillary electrophoresis (CE). The pertinent physicochemical properties, such as absorption spectrum, isoionic point, and solution conformation, of DTC were determined. The effects of varying such experimental parameters as DTC concentration, pH, and methanol content in the running buffer were assessed. CE separation of the enantiomers of 18 different compounds was achieved using DTC as the chiral selector under optimized background electrolytic conditions.

Contribution Of The Center-Of-Mass Fluctuation Of A Liquid Cluster To The Free Energy: A Monte Carlo Simulation Study, K.J. Oh, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The contribution of the center-of-mass (CM) fluctuation of a liquid cluster to the Helmholtz free energy was first discussed by Reiss, Katz, and Cohen (RKC). They argued that this contribution can be assessed via the free energy difference between the cluster with a fixed boundary centered on a fixed CM, and the cluster in which the CM was allowed to fluctuate. They estimated the free energy difference is to be about 20 k_bT. Here k_b is the Boltzmann constant and T is the temperature of the system. To examine this estimate, Abraham et al. later calculated …

In Situ Detection Method For Glutaminyl Cyclase Activity In Polyacrylamide Gels, Justin B. Houseknecht, Jeffrey S. Temple, Robert C. Bateman Jr.

Faculty Publications

No abstract provided.

Single-Head Spin Modes In Frontal Polymerization, Victor M. Ilyashenko, John A. Pojman

Faculty Publications

The single-head spin mode is the first two-dimensional pattern of self-propagating thermal reaction fronts observed after the planar front loses stability. A "hot spot" is observed to propagate around the periphery of the front. The dynamics of the single-head frontal polymerization regime were studied experimentally, and two novel results were found. The "hot spot" was measured and found to be superadiabatic. The relationship between the rotational velocity and the propagating velocity was found. Experimental data were also compared with the theoretical results based on the linear stability analysis and found to be in a reasonable agreement. (C) 1998 American institute …

Double Photoionization Of Helium, James A.R. Samson, Wayne C. Stolte, Z. X. He, Y. Lu, J. N. Cutler, R. J. Bartlett

Chemistry and Biochemistry Faculty Research

The cross sections for double photoionization of helium and the ratios of double to single ionization have been measured from the double-ionization threshold to 820 eV. The results are in very good agreement with several recent calculations.

Studies Of Surface Electrochemistry And Electrocatalysis At Atomic And Molecule Level, Shigang Sun

Journal of Electrochemistry

The main progresses achieved during last few years in our research group concerning studies of surface electrochemistry and electrocatalysis were reviewed in this present paper. Four topics were described: 1) the surface electrochemistry and model electrocatalysis of metal single crystal planes, 2) the electrocatalytic reaction mechanism and the control of reaction pathways at molecule level, 3) the reaction kinetics of electrooxidation of small organic molecules, and 4) the relationship between the properties and the surface chemical states of electrocatalyst. This review lays in emphasis on the demonstration of the results as well as the research direction of surface electrochemistry and …

A Preliminary Study On Thin Film Plasticizing Lithium Ion Battery, Quanfeng Dong, Hanxi Yang, Xinping Ai, Xiaohong Hu, Shengxian Li

Journal of Electrochemistry

A dry polymer electrolyte was made by plasticizing a copolymer matrix and further filling with liquid electrolyte. A thin-film lithium ion battery based on the dry polymer electrolyte was manufactured and its electrochemical properties were measured. It is found that the thin film lithium ion battery exhibits similar discharge properties to liquid electrolyte battery, and shows strong high rate capability.

Microelectrode Studies On The Pitting Corrosion Process Of Stainless Steel, Changjian Lin, Lijian Chen, Ronggui Du, Zude Feng, Jianguang Tang, Hongping Dai

Journal of Electrochemistry

Differing with the scanning microelectrode techniques, which scan microelctrode closely to the interface of electrode/electrolyte and make electrochemical imaging in a lateral spatial resolution, the technique of microelectrode with a micron diameter is of very high time-resolution and ratio of signal/noise in electrochemical measurements. The microelectrode technique allows double-layer capacitance and background current for a microelectrode to be drastically reduced due to the exposed area of a microelectrode is usually 6～8 orders of magnetite lower than that of a conventional electrode with large-scale exposed area. Microelectrode was recently developed as a new powerful electrochemical technique and widely used in the …