Heidelberg, Universiẗat, Diss., 2002. / Dateiformat: tgz, Dateien im PDF-Format.

Universiẗat, Diss., 1999--Marburg.

Thesis (Ph. D.)--University of Washington, 1987. / Vita. Includes bibliographical references (leaves [73]-75).

Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2005Bitstream added on 2014-06-13T19:37:21Z : No. of bitstreams: 1 rocha_pcf_me_guara.pdf: 3559287 bytes, checksum: 5d2438ca3739708a996fc1df3aa87c36 (MD5) / Universidade Estadual Paulista (UNESP) / O tema proposto surgiu do interesse da ELEB - Embraer Liebherr Equipamentos do Brasil, em buscar por novas alternativas para a recuperação dimensional de peças. O processo de niquelação tipo sulfamato, é com freqüência utilizada em aplicações de engenharia devido às excelentes propriedades mecânicas do revestimento, tais como, alta ductibilidade e baixa tensão residual. Este estudo objetivou analisar a influência do revestimento de níquel, processo sulfamato, eletrodepositado no aço de alta resistência, ABNT 4340 , na dureza 53 HRc, como camada simples e como camada intermediária sob cromo duro convencional. A análise foi realizada por meio de dados obtidos nos ensaios de fadiga por flexão rotativa, em amostras revestidas somente com níquel, com cromo duro mais camada intermediária de níquel, ambas com e sem prétratamento shot peening, comparativamente às amostras do metal base. Os resultados demonstram que a aplicação da camada de níquel, processo sulfamato, reduziu o desempenho em fadiga tanto na alternativa somente níquel como na alternativa camada intermediária sob o cromo duro. Entretanto, o pré-tratamento shot peenig se mostrou eficaz, atenuando o efeito da redução em fadiga nas duas alternativas estudadas. / This work proposes to reach the interest of ELEB- Embraer Liebherr Equipamentos do Brasil in searching for new alternatives to parts dimensional recovery. The process of nickel electroplating sulphamate has often been used on engineering appliances due to its high mechanical property, such as ductility and low residual stress. This study aims to analyse the nickel layer effect, sulphamate process, electroplated on high strength stell, ABNT 4340 on hardness HRc 53, as simple layer and as interlayer under conventional hard chromium. The analysis was performed by means of obtained data from rotating bending fatigue tests of specimens coated with nickel only and coated with hard chromium plus nickel sulphamate interlayer, both with and without shot peening pre-treatment, in relation to ABNT 4340 specimens. The results showed that the nickel sulphamate coat decreased the ABNT 4340 fatigue performance in both cases, in the one coated with nickel only, and the one coated with hard chromium plus nickel sulphamate interlayer. However, the shot peeing pretreatment was efficient, because the fatigue loss effects have been reduced in both alternatives studied.

M.Sc. / Several bis[1-ferrocenyl(ethyl)pyrazolyl palladium dichloro (complexes 1 and 3) and palladium chloromethyl complexes (complexes 2 and 4) have been synthesized by the reactions of 1- ferrocenyl(ethyl)-1N-pyrazole and 1-ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole with [PdCl2(NCMe)2] and [PdClMe(cod)] respectively. Furthermore, a library of phosphorus^nitrogen (P^N) ferrocenyl(ethyl)-amine and -pyrazolyl ligands have been successfully synthesized using the well known Ugi amine (compound 5) as intermediate. 1- [2-{diphenylphosphino}ferrocenyl](ethyl)amine and 1-[{2-diphenylphosphino}ferrocenyl](ethyl)- pyrazolyl Ni(II) and Pd(II) complexes were synthesized by reacting 1-[2- {diphenylphosphino}ferrocenyl](ethyl)dimethylamine, 1-[2-{diphenylphosphino}ferrocenyl](ethyl)- 1N-pyrazole and 1-[2-{diphenylphosphino}ferrocenyl](ethyl)-1N-(3,5-dimethyl)pyrazole with [NiCl2•6H2O] (compounds 12 and 16), [NiBr2(DME)] (compounds 13, 17 and 19), [PdCl2(NCMe)2] (compounds 10, 14, and 18) and [PdClMe(cod)] (compounds 11 and 15), respectively. 1-[2- {Diphenylphosphino}ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole (compound 9) was synthesized by two distinct methodologies. In one method, 1-ferrocenyl(ethyl)dimethylamine was converted to 1-[2- {diphenylphosphino}ferrocenyl](ethyl)dimethylamine before it was subsequently reacted with 3,5- dimethylpyrazole to produce 1-[2-{diphenylphosphino}ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole. In the other method, 1-ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole was converted to 1-[2- {diphenylphosphino}ferrocenyl](ethyl)-1N-(3,5-dimethyl)pyrazole before the reaction with 3,5- dimethylpyrazole, producing 1-[2-{diphenylphosphino}ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole. These compounds synthesized via different methods as well as their palladium dichloro complexes show different structures in solution, but solid state structural analysis agrees on the same structure. The structural difference in solution is contributed to the high degree of flexibility at the stereogenic centre of the complex. The Ni(II) ferrocenyl phosphine complexes 12, 13, 16, 17 and 19 exist in equilibrium between diamagnetic square planar form and paramagnetic tetrahedral form. The tetrahedral geometry is xvi favoured over the square planar geometry, purely on steric grounds, but the square planar geometry occurs with d8 complexes because of the more favourable electronic situation of the complex. Activation of these P^N palladium and nickel ferrocenyl- amine and -pyrazolyl pre-catalysts 10, 12, 13, 14, 16, 17, 18a and 19 with EtAlCl2 results in the oligomerization of ethylene to C4 and C6 alkenes, followed by subsequent Friedel-Crafts alkylation of the toluene solvent. Moderate catalytic activities of up to 659 kg of alkylated toluene products.mol-1 Ni. h-1 were observed for catalyst 13 at 20 bar ethylene pressure. In general, the Ni(II) pre-catalysts were more active than the Pd(II) precatalyst.

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[From Introduction]. This thesis deals with the determination of copper and nickel both separately and in each other's presence. The work is divided into two sections, one of which treats the subject from the theoretical side while the other contains an account of the practical work performed by the author. In the theoretical section, an attempt is made to summarise the better-known methods for the determination of copper and nickel, and at the same time, to incorporate such improvements, criticism and variations as have appeared in the literature. The subject is so vast that its summary in so short a space must necessarily be incomplete. Yoe and Server, for example, quote 111 references on the subject of the nickel-dimethylglyoxine with other ions. Only a fraction of the literature was available, and space permitted only a fraction of this to be abstracted in the following pages.

As part of a strategic research initiative at UBC to design and evaluate integrated underground mining and mineral processing systems, work has been done to determine how to utilize the coarse rejects of pre-concentration in the underground environment. An amenability study for nine orebodies from four of Xstrata Nickel’s Ontario operations evaluated both processing and waste disposal methods. Metallurgically the orebodies showed amenability to dense media separation and conductivity sorting. The dense media results showed high mass rejections and high metal recoveries for all nine orebodies. Conductivity sorter results were not as consistent, but still showed good results. Dense media rejects were examined to determine the applicability of their use in rockfills and composite minefills. The geotechnical properties indicated that the rejects would provide a competent material for minefills. The mix designs were examined for both strength and rheological properties and showed that fills utilizing rejects were comparable to fills currently used by industry. Composite fills containing rejects had significantly lower void ratios, decreasing cement requirements for a given strength requirement. Conceptual designs for pre-concentration systems based on the metallurgical, reject characterization, and mix design were developed for each of the four mines in the study. The designs took into consideration the current mining plans. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

The corrosion behaviour of nickel and monel in aqueous fluoride solutions was studied by potentiostatic polarization techniques and surface examination of the corroded specimens. Nickel does not exhibit the usual active-passive transition for 0 < pH < 4.0 but corrodes rapidly especially at the grain boundaries. In the range 4.0 < pH < 6.5 the nickel-polarization curve contains two active regions. Nickel is passive in contact with a fluoride solution with 6.5 < pH < 12.0. Polarization curves of nickel in fluoride solutions of varied pH's and fluoride ion concentrations in the range 4.0 < pH < 7.0 revealed that the current as a function of potential in the first active region is independent of fluoride ion concentration but dependent on pH. The currents in the first passive and second active regions are a function of pH and fluoride ion concentration. Surface examinations showed that nickel corrodes at the grain boundaries in the second active region. A mechanism has been proposed which accounts for corrosion in the second active region by F⁻ adsorption and passivation by either H₂O or OH⁻ adsorption on the anodically polarized metal surface. A mathematical analysis based on competitive adsorption of these species as a function of electrode potential is shown to be consistent with the experimental data. Monel corrodes at less than half the rate of nickel at the mixed potential in fluoride solutions with 0< pH < 6.5 due to its larger hydrogen overvoltage. Monel exhibits active-passive behaviour similar to nickel but with the passive current up to 6 times as large. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate