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Glycals : An Extended Study Of The Ferrier-Dimerization, Andreas H. Franz

University of the Pacific Theses and Dissertations

C-linked disaccharides were synthesized from 3,4,6-tri-O-acetyl-D-glucal 1 (1,5- anhydro-3,4,6-tri-O-acetyl-1,2-dideoxy-D-arabino-hex-I-enopyranose), 3,4,6-tri-O- acetyl-D-galactal 2 (1,5-anhydro-3,4,6-tri-O-acetyl-1,2-dideoxy-D-lyxo-hex-1- enopyranose) and 3,4-di-O-acetyl-L-fucal 3 (1,5-anhydro-3,4-di-O-acetyl-1,2,6-tri-deoxy- L-lyxo-hex-1-enopyranose) under Lewis acid catalysis (Scheme 1) and compound 4 was further derivatized at the double bond. Dihydroxylation of the glucose dimer 4 gave high allo-diastereoselectivity. The reactions used in the derivatization of 1 were subsequently applied to 2 and 3. The overall yield of 3 was improved to 70 %. All three glycals (10% solution in toluene) reacted quickly with boron trifluoride to give dimerization products in 40-60% yield. Futile attempts at de-O-acetylation of the 2',3'-unsaturated dimer revealed the necessity of …

Dichlorobis[1,3-Dimethylimidazole-2(3h)-Selone-Se]Cobalt(Ii), Daniel J. Williams, Timothy Jones, Edward D. Rice, Kerri J. Davis, John A. Ritchie, William T. Pennington, George L. Schimek

Faculty Articles

The crystal structure of the title compound, [CoCl₂(C₅H₈N₂Se)₂], shows a discrete molecular structure with tetrahedral geometry around the cobalt ion. The mean Co-Cl and Co-Se distances are 2.277 (3) and 2.456 (3) Å, respectively. Bond angles around the Co atom range from 101.1 (1) to 120.0 (1)°. Ring distances and angles in the ligand compare favorably with the literature values of analogous compounds, and show significant increases from values observed in the uncoordinated selone. However, the mean C-Se bond distance of 1.88 (2) Å shows no significant difference from the …

Characterization Of Iron Oxides And Atmospheric Corrosion Of Steel, Sei Jin Oh

Physics Theses & Dissertations

The study of corrosion behavior was performed using three different analytical techniques, which provided information on the formation, development and layering of iron oxides on the corrosion products as a function of atmospheric conditions, exposure time and type of steel. In particular, the protective layer formed on weathering steel was investigated as a function of different amounts of alloying elements in the steel, atmospheric conditions and exposure times. Combined together, the results provided a better understanding of the atmospheric corrosion behavior of steel, and formed a part of database of the atmospheric corrosion characteristics.

Accurate characterization of the iron oxides …

Efficient And General Synthesis Of Novel Β-Polyfluoroalkoxy Vinamidinium Salts, Koichiro Kase, Mitsuyoshi Katayama, Takashi Ishihara, Hiroki Yamanaka, John T. Gupton

Chemistry Faculty Publications

Novel β-polyfluoroalkoxy vinamidinium salts 3 and/or 4 were synthesized in good yields by the reaction of N-(2- polyfluoroalkoxy-3 ,3-difluoro-1-propenyI)trimethylammonium iodides (2), prepared from N-(2,3,3-trifluoro-1-propenyl)trimethylammonium iodide (1), with secondary amines in MeCN at 70 °C for 1 h. The salts were also obtainable in comparable yields by the one-pot reaction of 1 with sodium polyfluoroalkoxide followed by treatment with amines.

Efficient Implementation Of Image Compression-Postprocessing Algorithm Using A Digital Signal Processor, Nadir Sinaceur

Dissertations and Theses

In this thesis, an attempt has been made to develop a fast way to implement a post-processing algorithm for image compression. All the previous tests for this postprocessing algorithm, which we will present, have been only software based and did not consider the time parameter.

For this purpose a new algorithm is used to compute the 2-D DCT transform. This change made the process a lot faster on a Spare 5 workstation. We have then decided to further increase the speed of the post-processing scheme by implementing it on the ADSP21020 chip.

The results show that such a chip can …

Microwave Plasma Chemical Vapor Deposited Diamond Tips For Scanning Tunneling Microscopy, Sacharia Albin, Jianli Zheng, John B. Cooper, Weihai Fu, Arnel C. Lavarias

Electrical & Computer Engineering Faculty Publications

Diamond microparticles were grown on etched tungsten wires using a microwave plasma-assisted chemical vapor deposition process. The apexes on cubo-octahedral particles bound by {100} and {111} facets were effectively used as tunneling tips for scanning tunneling microscopy. The atomically resolved surface image of highly oriented pyrolytic graphite was acquired. Tunneling characteristics revealed a higher electron emission from the diamond tips than that from the platinum–iridium tips. The same diamond tips were used to produce surface indentation and its image. © 1997 American Institute of Physics.

Nickel Catalyzed Cyclizations Of Alkynyl-Etones And Their Application To The Formal Synthesis Of Pentalenic Acid, Kevin Schlosser

Honors Theses

Pentalenic acid is a very important molecule because it is a biosynthetic intermediate of pentalenolactone, which has antibiotic effects on Grampositive/ negative bacteria and pathogenic fungi. These effects are due to its ability to inhibit glyceraldehyde 3-phosphate dehydrogenase.1 However, the total synthesis of pentalenic acid is very lengthy.2 This project will begin the process of finding a more convenient route to pentalenic acid. Previously in this laboratory there have been experiments conducted in the cyclization of enones with nickel (0)3 It is hypothesized that this method can be used to shorten the preparation of pentalenic acid. As illustrated by the …

A Chemical Pathway To The Formation Of Chlorinated Compounds During Combustion, Xiaodong Yang

Masters Theses & Specialist Projects

Two reactions, the Deacon reaction and the chlorination of phenol, which are the postulated starting steps for the formation of chlorinated dioxins during the incineration of the refuse derived fuel, were investigated in this work. Reactions were conducted in a tube furnace, and the products were trapped and analyzed by gas chromatography/mass spectroscopy. It was shown that the Deacon reaction was favored at higher temperatures. The chlorination of phenol in vapor phase was found to begin at temperatures as low as 250°C and to be favored at higher temperatures. The ortho and para positions in the phenol ring are the …

A Study Of The Behavior Of Chlorine And Organic Compounds During Combustion In An Afbc System, Jenny Heidbrink

Masters Theses & Specialist Projects

The purpose of this study is to understand the behavior of chlorine and the emission of organic compounds during combustion in an atmospheric fluidized bed combustion (AFBC) system. Inefficient, uncontrolled use of coal gives rise to organic emissions which can be detrimental to health. The chlorine in coal may cause corrosion problems during utilization, if its concentration is high enough. The method for collection of the emissions of organic compounds involved the use of a Tenax resin as an absorbent for the organic compounds as they were emitted from the combustor. A combined gas chromatography - mass spectrometry (GC-MS) technique …

New Enantioselective Lewis Acid Catalysts, Mustafa Guzel

All Theses

Recently, many organic chemists have been ultimately interested in research in the synthesis of enantiomerically pure organics which are useful to synthesis of biologically active agents and prodrug substances. In the past decades, the new concepts in catalyst design unexpectedly explored the direction of natural product synthesis. In many cases, using enantioselective catalysts are the most suitable and efficient method into enantiopure systems.

Mass Transport Of Volatile Organic Compounds Between The Saturated And Vadose Zones, Monte S. Harner

Theses and Dissertations

Volatile organic compounds (VOCs) dissolved in the saturated zone are transported into the vadose zone primarily by gaseous phase diffusion. If the saturated zone is remediated, VOCs present in the vadose zone may become a secondary source of contamination for the groundwater. The amount of VOCs that remain in the vadose zone is dependent on site hydrology, soil properties, and the chemical properties of the contaminants. The purpose of this study was to determine what conditions caused VOC concentrations in the vadose zone to significantly recontaminate the saturated zone. A one-dimensional numerical model was developed to investigate the transport of …

Modeling Marine Exposure To Polychlorinated Biphenyls From Sunken Ships, Charles N. Wendt

Theses and Dissertations

In the past, the U.S. Navy has routinely conducted SINKing EXercises (SINKEX) for training, weapon effectiveness tests, and economic disposal of aging assets. Recent concern over polychlorinated biphenyl (PCB) chemicals aboard such target vessels has resulted in a suspension of SINKEX. The U.S. Navy has approximately 200 vessels currently requiring such disposal. Environmental legislation and health concerns preclude selling such vessels to foreign governments or scrapping. This work attempted to model the fate and transport of these PCBs by examining their transport to coastal water and their accumulation in the marine food chain. The model includes biodegradation, upwelling, partitioning of …

Inhomogeneity In Gelation And Nonuniversality Of Sol-To-Gel Transitions Studied By A Computer Simulation Model, Yi-Min Liu, R.B. Pandey

Faculty Publications

No abstract provided.

The Effect Of Chromium Compounds On The Mutagenic Rate Of Benzo[A]Pyrenediolepoxide In Human Fibroblasts, Yordanos Tesfai

Masters Theses

Cancer researchers are interested in identifying the environmental causes and synergistic influences of different chemical carcinogens in order to decrease the risk of cancer. There are numerous studies which have investigated the effect of individual carcinogens but relatively few in which a well defined mixture of chemicals have been used. The present study was performed to examine the effect of chromium compounds on benzo[a]pyrene diolepoxide (BPDE) induced cytotoxicity and mutagenicity in human fibroblasts. Cytotoxicity was measured by the ability to fonn colonies while selection of 6-thioguanine resistant mutants were used to study mutagenesis in human fibroblasts.

Our results indicate that …

Side Chain Effect On Micellarly Catalyzed Hydrolysis Of Hydroxamic Acids In Perfluorooctanoic Acid Environment, A.C. Menik Fernando

Masters Theses

The side chain effect on micellar catalysis of hydroxamic acids with perfluorooctanoic acid as the reactive counterion surfactant in aqueous acetonitrile solution has been demonstrated in this thesis.

The rate constant-surfactant concentration profiles were used to estimate the critical micelle concentration and the second order rate constant for hydrolysis in the aqueous bulk phase.

The pseudo-phase ion exchange model satisfactorily explains the surfactant effect. The second order rate constants in the aqueous bulk phase show a direct relationship with steric substituent constants. The major influence of the change in micellar catalysis is the location in the micelle where the substrate …

Epa Overestimates The Benefit Of Biennial Inspection And Maintenance, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

The United States Environmental Protection Agency (EPA) computer model of mobile source emissions is used to estimate the benefits of future emissions control programs. Four input assumptions are discussed, each of which tends to overestimate the benefits of biennial testing programs. The assumptions are: each model year drives the same number of miles; high/superemitters, absent initially, increase linearly with mileage; inspection and maintenance (I/M) readings are invariant, and I/M repairs last forever. States opting for these programs should be aware that the predicted benefits may not materialize.

Elucidation Of Vancomycin's Enantioselective Binding Site Using Its Copper Complex, Usha B. Nair, Samuel S.C. Chang, Daniel W. Armstrong, Yasir Y. Rawjee, Drake S. Eggleston, James V. Mcardle

Chemistry Faculty Research & Creative Works

Vancomycin forms a stable complex with Cu2+ in neutral aqueous solutions. The enantioselectivity of native vancomycin was compared to that of the copper-vancomycin complex using capillary electrophoresis (CE). There were significant differences in their enantioselectivities. This can be attributed to the fact that copper ion coordinates with some of the same functional groups in vancomycin that are essential for chiral recognition and enantioresolution. An amine moiety that provides one of the more important enantioselective interactions was identified. This chiral interaction site was illustrated using a color-coded, space-filling model of the X-ray crystal structure of the copper-vancomycin complex. Successful enantioselective interactions …

Rapid Method For Determination Of Iodine Numbers Of Vegetable Oils, Ondrej Hendl

Masters Theses

There is a great deal of interest by the public about the total unsaturation of fats and oils used in commercial products as an indication of nutritional value. Dealers in fats and oils are extremely interested in characterizing these products. The unsaturation is a guide to the expected stability of food additives, such as edible oils and foods in which they are used. Unsaturation is typically evaluated as an iodine number (IN), calculated for these additives based on their consumption of iodine through addition across the carbon-carbon double bonds. The classical titration method can typically take 45 minutes.

The investigation …

The Biodegradation Characteristics Of Proposed Fuel Systems Icing Inhibitors (Fsii), Charles E. Meshako

Theses and Dissertations

The biodegradation characteristics of three fuel system icing ihhibitors (FSII) were evaluated. FSII are jet fuel additives that partition into water readily and are present in the water drained from storage tank bottoms in concentrations approaching 40%. These concentrations raise concerns as to the disposal and handling of these wastes. The current FSII, DiEGME was evaluated along with two new candidates, dipropylene glycol and glycerol formal. DiEGME appeared to be moderately but not completely biodegradable. It is likely that much of it would be removed in a wastewater treatment plant. Dipropylene glycol only showed signs of degradation after more than …

Porous Gas Diffusion Oxygen Cathode For Electrodialysis Process, Hongmei Liu, Baolian Yi

Journal of Electrochemistry

In the process of producing silica sols by electrodialysis, with porous gas diffusion oxygen cathode instead of steel cathode, the cell voltage can be reduced 0.86～1.13 V,the power consumption of alkali silica sols (pH=9.5) is about cut down 16%, while the current efficiency has no changing. With porous gas diffusion oxygen cathode instead of steel cathode, the electrolysis electrodialysis process can be returned to electrodialysis process.

Studies Of Electrochemical Behaviors Of Cytochrome C On Pretreated Gold Electrode, Jin Luo, Lingling Wu, Shaohua Huang, Zhonghua Lin

Journal of Electrochemistry

The quasi reversible responses of both adsorbed and bulk cytochrome c at the pretreated gold electrode are observed. The adsorption behaviors and reaction kinetics have been studied using in situ FTIR spectroscopy, UV/Vis reflection spectroscopy, voltammetry, AC impedance and potential step methods. The results show that the cytochrome c can irreversibly adsorb on the gold surface in a complete monolayer and the adsorbed layer can mediate the redox reaction of the cytochrome c in the solution in the absence of promoter.

Electrochemical Studies Of Cyanocobalamin On Silver Electrode, Zhai Jin, Yang Pin, Donghong Zheng, Junwei Zheng, Tianhong Lu

Journal of Electrochemistry

The electrochemical characteristics of cyanocobalamin were separately studied on smooth and roughed silver electrode. It was found that the reduction of cyanocobalamin is two one electron steps on roughed silver but one two electron step on smooth electrode. The reason is due to the ability of absorption of the surface of electrode.

The Preparation Of Heteropoly Compound Polypyrrole Film Modified Electrode And Its Electrochemical Properties, Weiqing Wang, Xiumei Zhang, Long Cheng, Baifeng Liu, Shaojun Dong

Journal of Electrochemistry

Electronically conducting polypyrrole doped with heteropolyanions K₁₀H₃[Nd(SiMo₇W₄)₂]·xH₂O(denoted as [Nd(SiMo₇W₄)₂]^13-) was synthesized by electrochemical polymerization. This modified electrode maintains the electrochemical and electrocatalytic properties of heteropolyanion, with having good stability and electrocatalytic activity on the reduction of nitric oxide in acidic aqueous solution.

A Conductance Study Of Complexes Of Rare Earth With Cryptand (2.2) In Nonaqueous Solvents, Shichang Liu, Aiju Xu, Qiang Zhang

Journal of Electrochemistry

The coordination reaction of several rare earth nitrates with cryptand (2.2) in (CH₃)₂CO, CH₃CN, CH₃OH and DMF at 25 ℃ has been studied by means of using conductometric titration. The stability constants and the molar conductivities for the 1:1 coordination compounds were calculated. Since the complexation is accompanied by solvation of the Ln(Ⅲ) ion in nonaqueous solvents, for lanthanide series, there is more or less variation in stability constants of complexes of rare earth with cryptand (2.2) when atomic numbers increas. The orders of the Λ_ML(NO3)3 values about the same rare …

Poisson Boltzmann Integral Equation In A Charged Capillary And Its Numerical Solutions, Yongxian Qian

Journal of Electrochemistry

The nonlinear Poisson Boltzmann integral equation (PBIE) governing electrostatic potential distribution in a charged capillary filled with symmetric electrolytes is derived from the same physical principles as used in deriving nonlinear Poisson Boltzmann differential equation, usually called PBE. PBIE is then numerically solved by iteration. In iterate computation discrele values of electrical potential is soly needed, and the first or higher orders of the differential of the potential is not used any more. This does essentially remove the difficulty caused by the very steep variation of the potential near the wall of the capillary. The results of the seven examples …

Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅰ. Influences Of Oxidation And Reduction Pretreatment On Anode Performance, Shuhua Ma, Hanju Guo, Ji Li, Hongze Liang, Xiabin Jing, Fosong Wang

Journal of Electrochemistry

The influences of the trace oxygen containing functional groups on surface of carbon material on cell performance of carbon anode for lithium ion batteries were studied by means of the pretreament in various oxidant/reductant systems. The results showed that the rich oxygen containing functional groups impaired the cell performance of carbon material anode, and the reduction of these groups in quantity and oxidation degree can increase charge/discharge capacity and improve first charge/discharge efficiency. The reason was also discussed in the light of effects of surface organic groups on decomposition reactivity of electrolyte and formation process of surface passivating film.

The Current Distribution On The Anode Surface Of The Seale Oval Tubular Lead Acid Battery, Renao Gu, Jianlin Yao, Zhengfa Deng, Ru Sun, Liren Wu, Zhongsi Jiang, Wangen Miao

Journal of Electrochemistry

The current distribution on anode surface of sealed lead acid batter under different discharge current and degree was studied by chemical analytical method for the first time. We can conclude that the current distribution is not even. The current density on the edge of the electrode surface and the electrode terminal are bigger than other areas, that is, there are edge effect and terminal effect, and these effect are more obvious when the discharge current is 100 A and degree is 100%.

High Active Platinum Plated Titanium Electrode, Xiufeng Xiao, Zeshan Zhu, Yanzhen Chen, Wenyun Hu

Journal of Electrochemistry

To prepare the adherent and high active platinum plated titanium electrode, ultrasonic agitation technology and the best conditions of electrodeposition were adopted. Ultrasonic agitation technology can be improved the cohesion between coatings and substrate. The activity of electrode has related to the double layer capacity of electrode, which was due to the electrode rugosity.

Comparison Of The Charge/Discharge Charasteristics Between Ni-Cd And Ni-Mh Battery And Its Improvement Of Manufacture Technique, Yumimg Wang, Jinsheng Chen

Journal of Electrochemistry

Based on the difference of charge discharge charasteristies between Ni-Cd and Ni-MH battery, some appropriate manufacture technoque to improve the battery performances or to extend its service life are adopted.

Determination Of Organic Basis Of Hydrochloride By The Oscillopolarographic Titration, Yongfu Zhan, Zhaoren Meng, Guirong Zhao, Jianbin Zheng, Hong Gao

Journal of Electrochemistry

In this paper, diphenhydramine hydrochloride, ephedrine hydrochloride, procaine hydrochloride, vitamin B₁ and vitamin B₆ have been determined by the Oscillopolarographic titration. This method has not been reported in any papers up to now. The characteristics of the method are being quick and exact, easy to observe the final result and saving material tested.