Chemistry Commons^™

The Electroless Plating Ni-Fe-P Alloy And Its Voltammetric Behavior, Sen-Lin Wang, Hui-Huang Wu

Journal of Electrochemistry

Electroless Ni-Fe-P alloy deposition from an alkaline bath, containing sodium hypophosphite as reducer, boric acid as buffer agent and sodium citrate as complexing agent, was investigated. To increase the plating rate and to inprove the bath stability, the deposition parameters were optimized. The effects of process parameters (pH, temperature and mole ratio of [Fe²⁺]/([Ni²⁺]+[Fe²⁺]) on the plating rate and deposit composition were examined and it was found that the presence of ferrous sulfate in the bath has an inhibitory effect on the alloy deposition. As a consequence, the percentage of iron in the electroless …

The Mechanism Of Electrocatalytic Reduction Of Oxygen On Manganese Dioxide, Yu-Liang Cao, Han-Xi Yang, Xin-Ping Ai, Li-Fen Xiao

Journal of Electrochemistry

The oxygen electroreduction on the MnO₂ electrode was investigated by analysis of the polarzation properties of oxygen reduciton and its dependence on MnO₂ discharge state, in combination with the characterization of discharge intermediate and the kinetic parameters of the oxygen reduction. Based on the experimental observation and mechanistic analysis, it was suggested that the reduction of oxygen was closely related to the discharge behaviors of MnO₂. When MnO₂ was electrochimically reduced to MnOOH, it was immediately oxidized by oxygen molecules. Thus the oxygen reduction proceeds through continuous oxidation of the discharge product of MnO_{2 …}

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.

Study On The Electrochemical Behavior Of Methy1 Green And Methy1 Green-Cyclodextrin Supramolecule System, Yu-Jing Guo, Jing-Hao Pan, Chun-Hua Guo, Hong-Lian Zheng

Journal of Electrochemistry

Electrochemical behavior of methyl green in different kinds of solution and the supramolecule system of methyl green-cyclodextrin were studied. Inclusion constants of four cyclodextrin with emthyl green were determined by “electric current method”. The order of inclusion ability is HP-β-CD,β-CD,SBE-β-CD and CM-β-CD. The molar ratio of inclusion complexes of methyl green with CDs is 1:2. A possible mechanism was reported for methyl green.

Study Of Electrolyzed Pure Iron And Rrr-H Method, Wei-Min Cao, Ren-He Yin, Hui-Gen Yan, Yi-Bing Zhang, Ying-Chun Dai

Journal of Electrochemistry

The high purity electrolytic iron was made from scrap iron chips. The purity of electrolyzed pure iron was above 99.98% by chemical analysis. The resistivity was measured at 298 K and at 4.2 K under an applied longitudinal-magnetic field of 8000 e. The ratio of resistivity at 298 K to that at 4.2 K, The value of residual resistivity ratio (RRR H) roughly depended on the purity of iron. Pure iron electrolyzed on Ti substrate had very compact texture as evident by SEM.

Synthesis And Electrochemical Properties Of K2Feo4, Ning Zhou, Shi-Hai Ye, Yong-Long Wang, Xue-Ping Gao, Dong-Feng Lin, Zuo-Xiang Zhou, De-Ying Song

Journal of Electrochemistry

The K₂FeO₄ 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 K₂FeO₄. 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 …

Synthesis Of Polyunit Vapor Phase Inhibitor And Its Volatile Corrosion Inhibition Performance, Da-Quan Zhang, Li-Xin Gao, Guo-Ding Zhou

Journal of Electrochemistry

A Mannich Base derivative (BMMCH), containing two morpholinum moieties and one cyclohexylamnonium moiety, was synthesized through aminomethy1 reaction. Its configuration was verified by IR and ¹H-NMR. Its volatile rustproofing effect was appraised by volatile rustproofing sieve test and vapor inhabitability test. The result shows that BMMCH has good protection effect for carbon steel. BMMCH has lower volatility compared with dicyclohexylamnonium nitrite (DICHAN) via closed space volatile weight-loss test. The inhibition mechanism was studied by potentiodynamic polarization electrochemistry technique in ASTM simulated atmospheric water. The corrosion potential of carbon steel electrode shifted to a negative direction when BMMCH was joined …

Influence Of Marine Organisms Upon Corrosion Of Steel Piling Systems, Jiunn-Shyong Luo, Cliff Rau, Kuei-Ching Chen

Journal of Electrochemistry

To study the influence of marine organisms upon corrosion of ASTM A36 steel piling sysems, specimens were immersed in both natural and synthetic seawater. Electrochemical techniques such as linear polarization resistance and electrochemical impedance scan(EIS) were applied to evaluate corrosion of the steel. The results indicated that attachment of marine organisms to form fouling layers on the steel surface reduced general corrosion, but localized corrosion occurred underneath marine organisms. An equivalent circuit model was established to simulate attachment of marine organisms upon carbon carbon steel surfaces.

Electrochemical Response Of Deformed Marine Steel In Sea-Mud Containing Sulfate Reducing Bacteria, Yan-Liang Huang

Journal of Electrochemistry

The corrosion failure behavior of marine steel is affected by stress,which exists in offshore structures at sea-mud region. In order to conduct the study of stress on the electrochemical response of a selected steel, a kind of natural sea-mud containing sulfate reducing bacteria (SRB) was collected. The electrochemical response of cyclic stress of the specimen with and without cracks in sea-mud was analyzed.

Why Should Students Do Research?, Bruce R. Branchini

Convocation Addresses

No abstract provided.

Phase Changes In Internally Mixed Maleic Acid/Ammonium Sulfate Aerosols, Sarah D. Brooks, Rebecca M. Garland, Matthew E. Wise, Anthony J. Prenni, Melinda Cushing, Erika Hewitt, Margaret A. Tolbert

CUP Faculty Research

A temperature controlled flow tube system equipped with Fourier transform infrared (FTIR) detection of particle phase and relative humidity was used to measure the deliquescence and efflorescence of ammonium sulfate, maleic acid, and internally mixed maleic acid/ammonium sulfate particles. Our results indicate that maleic acid aerosols begin to take up water starting at a low relative humidity, ∼20%, and continue the constant uptake of water until the final deliquescence relative humidity (DRH), 89%, is reached. Internally mixed particles containing maleic acid and ammonium sulfate were found to deliquesce at a lower relative humidity (RH) than either of the pure species. …

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 5/16/03- 8/15/03, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the AAA Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral …

Development Of A Systems Engineering Model Of The Chemical Separations Process, Yitung Chen, Sean Hsieh, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

The AFCI program is developing technology for the transmutation of nuclear waste to address many of the long-term disposal issues. An integral part of this program is the proposed chemical separations scheme.

Nearly all issues related to risks to future generations arising from long-term disposal of such spent nuclear fuel is attributable to about 2% of its content. Such 2% is made up primarily of plutonium, neptunium, americium, and curium (the transuranic elements) and long-lived isotopes of iodine and technetium created as products from the fission process in power reactors. When transuranics are removed from discharged fuel destined for disposal, …

Synthesis Of Chiral Surfactants For Enantioselective Organic Synthesis., Kalyan Mondal

Electronic Theses and Dissertations

The first step of the synthesis of the hydrocarbon-based chiral surfactant (2) involved the methylation of (S)-leucinol to give (2S)-N-hexadecyl-N,N-dimethyl-(1-hydroxy-4-methyl-1-pentyl)-2-ammonium bromide (2.92g, 67%). The chiral surfactant was synthesized by reacting (2S)-N,N-dimethyl-2-amino-4-methyl-1-pentanol (1) with bromohexadecane (2.06g, 71%). The functionalized styrene for the polymer supported chiral catalyst (6) was synthesized by reacting (1) with 4-vinylbenzyl chloride. The polymerization was carried out with 10% of the functionalized monomer (5) (1.26g, 70.2%), 5% cross-linking agent divinylbenzene, and 85% of styrene with AIBN as the initiator. The structure of each of the products was confirmed by using FTIR and NMR spectroscopy. The activity of the …

Spectroscopic Examination Of The Catalytic Decomposition Of Hydrogen Peroxide By A Copper (Ii) Complex Of A Dissymmetric Schiff Base And An Imidazole Derivative., John D. Davis Jr.

Electronic Theses and Dissertations

Previous studies involving copper (II) complexed with a dissymmetric Schiff base and imidazole derivatives had identified catalase activity of these complexes towards H₂O₂. Reactions such as this are of great interest due to the important role of copper-based complexes in biological systems. Our research has been conducted to add to the base of knowledge regarding the efforts of other researchers to investigate copper complexes that exhibit similar reactivity as copper-based proteins towards dioxygen. The copper complex chosen for this study contained a tri-dentate Schiff base adduct which, when complexed with an imidazole derivative, limited the manner …

Growth, Conductivity, And Vapor Response Properties Of Metal Ion-Carboxylate Linked Nanoparticle Films, Michael C. Leopold, Robert L. Donkers, Dimitra Georganopoulou, Megan Fisher, Francis P. Zamborini, Royce W. Murray

Chemistry Faculty Publications

Nanoparticles of metals (Au, Ag, Pd, alloys) in the size range 1–3 nm diameter can be stabilized against aggregation of the metal particles by coating the metal surface with a dense monolayer of ligands (thiolates). The stabilization makes it possible to analytically define the nanoparticle composition (for example, Au140(hexanethiolate)53, I) and to elaborate the chemical functionality of the protecting monolayer (for example, Au140(C6)35(MUA)18, II, where C6 = hexanethiolate and MUA = mercaptoundecanoic acid). Network polymer films (IIfilm) on interdigitated array electrodes can be prepared from II, based on cation coordination (i.e., Cu2+, Zn2+, Ag+, methyl viologen) by the …

Investigation Of The Relationship Between Particulate Bound Mercury And Properties Of Fly Ash In A Full-Scale 100 Mwe Pulverized Coal Combustion Boiler, Sen Li

Masters Theses & Specialist Projects

There is an increasing concern over mercury emissions from coal-fired boilers. Coal-fired power generation accounts for approximately 33% of total mercury emission in the United States. Once it is emitted into the atmosphere and deposited on land or water, mercury can transform into methylmercury, an organic form. Mercury can then enter the food chain, which poses a potential threat to human health and the environment. To study the relationship between particulate bound mercury and fly ash properties, fly ash samples were collected from the mechanical hopper (MHP) and the electrostatic precipitator (ESP) of a 100 MWe pulverized coal-fired boiler and …

Direct Multielemental Analysis Of Solid Samples Using Laser Ablation Inductively Coupled Plasma Mass Spectometry And Pulsed Radio Frequency Glow Discharge Mass Spectrometry, Joseph Miller

Masters Theses & Specialist Projects

Direct solid sampling is an area of analytical research that has generated a large amount of interest in recent years. Two analysis systems offering fast and nondestructive methods of determining the elemental composition of substances, without requiring complicated sample preparation procedures, are laser ablation inductively coupled plasma mass spectroscopy (LA-ICPMS) and radio frequency glow discharge mass spectroscopy (rf-GDMS). A Cetac LSX-200 laser system coupled to a LECO Renaissance ICPMS was utilized to analyze coal and ash samples prepared by incorporation into a lithium borate matrix to form a disk. In addition, a VG 9000 Glow Discharge Mass Spectrometer (GDMS) with …

Receptor Activation Regulates Cortical, But Not Vesicular Localization Of Ndp Kinase, Betty C. Gallagher, Kimberly A.P. Mitchell, Gabor Szabo, Angela De S. Otero

Faculty Publications and Presentations

We used immunofluorescence techniques to determine the localization of nucleoside diphosphate (NDP) kinase in NIH-3T3 fibroblasts. We found that cytoplasmic NDP kinase can be separated into two populations according to subcellular localization and response to extracellular stimuli. Specifically, within minutes of stimulation of resting fibroblasts with serum, growth factors or bombesin, a portion of NDP kinase becomes associated with membrane ruffles and lamellipodia. Another pool of NDP kinase accumulates independently of stimulation around intracellular vesicles. Transfection of cells with activated Rac mimics, whereas expression of dominant negative Rac inhibits, the effects of extracellular stimulation on the translocation of NDP kinase …

Emission Color Tuning In Alq(3) Complexes With Extended Conjugated Chromophores, Radek Pohl, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

GraphicsA new method for the synthesis of 5-arylethynyl-8-hydroxyquinoline ligands using Sonogashira-Hagihara coupling was developed. The electronic nature of arylethynyl substituents affects the emission color and quantum yield of the resulting Al(III) complex. Photophysical properties of the metallocomplexes correspond to the electron-withdrawing/-donating character of the arylethynyl substituents. Optical properties of such AI(Ill) complexes correlate with the Hammett constant values of the respective substituents. This strategy offers a powerful tool for the preparation of electroluminophores with predictable photophysical properties.

Dielectric Permittivity And Electric Modulus In Bi2ti4o11, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, Robert W. Smith, John R. Hardy

Physics Faculty Publications

Frequency and temperature dependences of dielectric permittivity and electric modulus of pure and Ba-doped Bi2Ti4O11 were studied in the ranges of 1021–106 Hz and 2150–350 °C, respectively. We found that the antiferroelectric phase transition temperature of Bi2Ti4O11 decreases with Ba doping. In the permittivity studies, we also observed dielectric relaxation peaks shift to higher temperature with increasing frequency. Furthermore, in the electric modulus formalism, conducting peaks were uncovered above 150 °C in addition to the dielectric relaxation peak. We discussed the mechanisms for the dielectric relaxation and conduction processes based on TiO6 octahedra distortion and a space-charge model.

Dramatic Nondipole Effects In Low-Energy Photoionization: Experimental And Theoretical Study Of Xe 5s, Oliver Hemmers, Renaud Guillemin, E. P. Kanter, B. Krassig, Dennis W. Lindle, S. H. Southworth, R. Wehlitz, J. Baker, A. C. Hudson, M. Lotrakul, D. Rolles, Wayne C. Stolte, I. Tran, A. Wolska, S. Yu, M. Ya Amusia, K. T. Cheng, L. V. Chernysheva, W. R. Johnson, S. T. Manson

Environmental Studies Faculty Publications

The Xe 5s nondipole photoelectron parameter γ is obtained experimentally and theoretically from threshold to ∼200  eV photon energy. Significant nondipole effects are seen even in the threshold region of this valence shell photoionization. In addition, contrary to previous understanding, clear evidence of interchannel coupling among quadrupole photoionization channels is found.

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics - Phase Three, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The proposed work will combine chemical kinetics and hydrodynamics in target and test-loop lead-bismuth eutectic (LBE) systems to model system corrosion effects. This approach will result in a predicative tool that can be validated with corrosion test data, used to systematically design tests and interpret the results, and provide guidance for optimization in LBE system designs. The task includes two subtasks. The first subtask is to try to develop the necessary predictive tools to be able to predict the levels of oxygen and corrosion products close to the boundary layer through the use of Computational Fluid Dynamics (CFD) modeling. The …

Photofragmentation Dynamics Of Core-Excited Water By Anion-Yield Spectroscopy, Wayne C. Stolte, M. M. Sant'anna, Gunnar Ohrwall, Maria Novella Piancastelli, I. Dominguez-Lopez, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

Partial-anion and- cation yields from H₂O are presented for photon energies near the oxygen K edge. The O^- yield exhibits a feature above threshold attributed to doubly excited states, in contrast to the H^- and cation yields, which are nearly featureless above threshold. Additionally, the lack of the OH^- fragment indicates radiative decay and provides a negligible amount of anion formation.

Solubility And Freezing Effects Of Fe2+ And Mg2+ In H2so4 Solutions Representative Of Upper Tropospheric And Lower Stratospheric Sulfate Particles, Matthew E. Wise, Sarah D. Brooks, Rebecca M. Garland, Daniel J. Cziczo, Scot T. Martin, Margaret A. Tolbert

CUP Faculty Research

Chemical elements characteristic of earth minerals and meteorites are present within background tropospheric and stratospheric sulfate aerosol particles. However, it is unknown if these elements are present predominantly as solids, including possible sulfates, carbonates, and oxides, or rather as soluble aqueous metal ions or complexes. Further, it is unclear how these impurities could affect particle freezing. To address these questions, we have determined the total equilibrium metal solubility ([Fe²⁺]_T and [Mg²⁺]_T) in 20–90 wt % sulfuric acid solutions over the temperature range 200–300 K. We have measured solubilities using samples of MgSO_{4 …}

Trace Elements Characterization Of The Hydrothermally Deposited Tanzanite And Green Grossular In The Merelani – Lelatema Shear Zone, Northeastern Tanzania, Epj Malisa

Tanzania Journal of Science

Geochemical investigations of trace element contents of different rock samples were determined in the late Proterozoic metamorphic sequences of the Mozambique Belt along the Merelani–Lelatema shear zone, northeastern Tanzania. The area is composed of the following rock types: pelitic and semi-pelitic gneisses, psammitic, hydrothermally altered including carbonate-rich, carbonate-gypsum-rich, and iron-rich rocks, pegmatite dykes and crystalline limestones. Trace element characteristics of the principal rock units in and outside the shear zone have been compiled and studied. With the exception of higher barium contents in pelites, trace element contents in the psammitic and pelitic gneisses show some similarities while in the hydrothermally …

Corrosion Inhibition Of Carbon Steel By An Amine- Fatty Acid In Acidic Solution, Joseph Buchweishaija

Tanzania Journal of Science

The corrosion inhibition of carbon steel in 3% de-aerated NaCl acidic solution with amine–fatty acid corrosion inhibitor, KI384, was investigated at different temperatures using potentiodynamic polarization technique. The Corrosion rate was calculated in the presence and absence of inhibitor. The inhibition increased with an increase in inhibitor concentration and decreased with rise in temperature. The maximum percentage inhibitor efficiency was obtained at 35 oC. The percentage inhibition up to 99% was registered at a concentration of 10 ppm of KI384. The inhibitor acts as a mixed type at lower temperature and predominantly anodic at high temperature. The interrelationship between the …

Chemotaxonomic Distinction Of Selected Closely Related Acacia Species Using Chemical Properties Of Their Gum Exudates, Gs Mhinzi

Tanzania Journal of Science

Although Acacia senega var. senegal and Acacia senegal var. leiorhachis are regarded as being closely related botanically, their gum exudates have shown to possess different properties. The properties of the gum exudate from A. senegal var leiorhachis differ from that obtained from A. senegal var. senegal (widely accepted as the source of commercial gum arabic) by being much more viscous, less acidic and having higher proportions of insoluble gel fraction and nitrogen contents. The specific optical rotation values of the gum exudates from these two species have also been found to be different. It is proposed that some of the …

A Multicentered Approach To Integrated Qm/Qm Calculations. Applications To Multiply Hydrogen Bonded Systems, Brian W. Hopkins, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A multicentered integrated QM/QM technique has been developed. By separating high-level calculations in distinct regions of molecules, the multicentered approach supplants a single large high-level calculation with several smaller calculations. Due to the step polynomial scaling of traditional ab initio quantum chemical methods, this separation significantly enhances the computational efficiency of QM/QM methods. The straightforward implementation of this multicentered approach is illustrated with several large poly-alcohols that form hydrogen bonds with water. The largest alcohol-water complex contains 81 atoms. For properly selected model systems, this multicentered approach introduces essentially no error in the dissociation energies of these complexes relative to …