By using the building blocks Mo2(DAniF)3(O2CCH3) (DAniF = N,N'-di-panisylformamidinate) and [Mo2(cis-DAniF)2(NCCH3)4](BF4)2, a series of complexes with multiple dimolybdenum units, bridged by a variety of linkers and having various oxidation states, has been synthesized and studied by various physical and chemical methods. The isomeric neutral diamidate-bridged molecules, α– and β– (DAniF)3Mo2(ArN(O)CC(O)NAr)Mo2(DAniF)3 (Ar = p-anisyl), have been oxidized to give the PF6 salts of the four cations α1+, α2+, β1+, β2+; all four structures together with supporting evidence show that in α1+ and α2+ the unpaired electrons are localized while in β1+ and β2+ they are delocalized in the time scale of these experiments. It is also found that a hydroxide bridged complex having a [Mo2](µ-OH)2[Mo2] core undergoes a oxidative deprotomation, both in solution and in crystals, to a compound with a [Mo2](µ-O)2[Mo2] core. A probable key intermediate with one OH and one O bridge has also been characterized. One electron oxidation of the tetrabridged compounds [Mo2(cis-DAniF)2]2(µ-X)4, where X is a halogen atom (Cl, Br, I), produces a decrease of about 0.24 Å in the separation between the midpoints of the multiply bonded dimolybdenum units. DFT calculations suggest partial bond formation during the oxidation, which is consistent with NIR, EPR and electrochemical measurements. Additionally, a pair of isomeric cyclic triads containing three [Mo2(cis-DAniF)2]2+ units, bridged by six fluoride anions, have been synthesized and crystallographically characterized. The symmetry of the α isomer is C2v because the three [Mo2] units are oriented in two orthogonal directions while that of the other isomer is D3h because the three [Mo2] units are parallel. No direct interconversion between isomers has been detected by heating or irradiation of solutions but oxidation of the α isomer first generates an α+ species that changes to β+. Finally, reaction of [Mo2(cis-DAniF)2(NCCH3)4](BF4)2 and Bun 4NBH4 in ether gives [Mo2(cis-DAniF)2]2(µ-H)4 (14), a compound whose Mo4H4 core may be described as an elongated tetrahedron in which the four H atoms are along the four long edges and the Mo2 units along the short edges.

Thesis (doctoral)--University of Oulu, 2000. / Includes bibliographical references. Also available on the World Wide Web.

Sixty to eighty per cent of the software life-cycle cost is spent on the software maintenance phase because software maintenance is usually more difficult than original development and legacy systems are generally large and complex. Software reuse has recently been considered as a best solution to enhance the productivity of a software development team and to reduce maintenance costs. In addition, Software Configuration Management (SCM) is a central part of software maintenance as it is associated with changing existing software and is a discipline for controlling these changes. Thus, both software reuse and SCM have been proposed for making a significant improvement in productivity, quality and cost. However, so far these two technologies have been investigated separately. In order for software reuse and SCM to produce effects by synergy, both approaches require to be introduced into a maintenance environment together. Since software reuse and SCM, and software reuse and software maintenance have many similarities in their activities, these disciplines can be integrated within a software maintenance environment. This research has therefore developed an integrated process model for 'Maintenance with Reuse (MwR)', that supports SCM for a reuse library which is actively maintained for use in a software maintenance environment. This thesis addresses an integrated process model called the MwR model and its prototype tool TERRA (Tool for Evolution of a Reusable and Reconfigurable Assets Library) that consist of a configuration management (CM) process, reuse process, maintenance process and administration of a reuse library. The MwR model and TERRA provide reusers and maintainers with many activities of these four processes such as classifying, storing, retrieving, evaluating, and propagating reusable components, including controlling changes to both reusable components and existing systems. The process model of an integrated approach has been developed and validated using Process Weaver. The TERRA tool has been implemented on the WWW so that the prototype can provide portability, traceability, integration with existing tools, and a distributed maintenance environment. The TERRA prototype has been tested and evaluated through a scenario based case study. Several scenarios based on real data have been created and used for the case study so that an organisation can apply the model and tool to its maintenance environment without many problems. The software maintenance community is facing serious problems with legacy systems, such as a ever increasing frequency of changes and backlogs, lack of integrated tools and methods, and lack of software maintenance support environments. The control and management of changes to the software components in a reuse repository are crucial to successful software development and maintenance. If the component is being used in multiple systems effects of uncontrolled change are more critical. However, reuse libraries and servers currently available have not been successful as they do not support further development or maintenance of the reusable components. In addition, most of them are not sophisticated since they have not been linked to a development/maintenance environment. The integrated model of MwR can overcome many problems that exist in software maintenance and reuse through introduction of SCM functionalities into a maintenance environment. Thus, the integration of these common activities will greatly contribute to enhancing the productivity and quality of software, and will additionally lead to reducing the costs and backlogs of changes within a maintenance environment.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed February 4, 2008) Includes bibliographical references (p. 163-165).

Thesis (Ph.D.)--McMaster University, 2002. / In title, numbers in chemical formula are subscript. Adviser: John Greedan. Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.)--McMaster University, 2002. / In title, numbers in chemical formula are subscript. Adviser: John Greedan. Includes bibliographical references. Also available via World Wide Web.

Submitted by Marcele Costal de Castro (costalcastro@gmail.com) on 2017-10-10T16:47:10Z No. of bitstreams: 1 LEONARDO FALCÃO KOBLITZ M.pdf: 2798440 bytes, checksum: e6bbe4d0c09a231a9612c35acb27e46b (MD5) / Made available in DSpace on 2017-10-10T16:47:10Z (GMT). No. of bitstreams: 1 LEONARDO FALCÃO KOBLITZ M.pdf: 2798440 bytes, checksum: e6bbe4d0c09a231a9612c35acb27e46b (MD5) Previous issue date: 1991-04 / Este trabalho apresenta o SAGCS, uma ferramenta automatizada para gerenciamento da configuração de software para ambientes DOS. Além de controlar o acesso aos arquivos sob seu controle, fornece vários relatórios, que permitem o usuário acompanhar precisamente a evolução do sistema. Em conjunto com esta ferramenta, são sugeridos um modelo e procedimentos para a elaboração e implantação de um plano de gerenciamento da configuração de software que melhor atenda as características de cada projeto de software.

No description available.

Unsaturated fatty acids of known degree, position, and configuration of unsturation were esterified, and stereospecifically dihydroxylated at the double bond(s). cis-Hydroxylation was effected using Woodward's reagent (silver acetate/iodine/acetic acid), while trans-hydroxylation was effected using Fenton's reagent (hydrogen peroxide/ferrous sulfate/acetic acid). Diols derived from monounsaturated esters were recovered quantitatively, while tetraols derived from diunsaturates were lost, presumably during extensive washing. The stereospecifically dihydroxylated esters were analyzed by thin-layer chromatography on borate-impregnated silica gel plates, and by gas-liquid chromatography, on a nonpolar capillary column, as the trimethylsilyl, acetyl, n-butylboronyl, isopropylidene, and trifluoroacetyl derivatives. For each derivative, the erythro and threo diols were readily separable, and some resolution of positional isomers was observed. Thus, the cis/trans configuration, and in some instances, the position of unsaturation of the original monounsaturated fatty acid may be deduced. However, gas chromatography-mass spectrometry of appropriately derivatized diol esters is required for unambiguous determination of position of unsaturation in most cases. These reactions are simple, use readily available reagents, and require relatively little operator attention. Further, they do not require specialized apparatus, as do hydrogenation and ozonolysis, or potentially toxic chemicals, such as osmium tetroxide. This series of analyses was applied to the unsaturated non-hydroxylated fatty acids of Legionella species, which were shown to be monounsaturated and of the cis Δ9 family. Position of unsaturation was confirmed by gas chromatography-mass spectrometry.

Yes / The effect of extruder screw configuration on the dispersion and properties of compatibilised polypropylene (PP)/multi‐walled carbon nanotube (MCNT) composite is investigated. Three principle screw designs with mainly conveying elements (medium intensity), kneading elements (high intensity), and folding elements (chaotic mixing) were used to prepare polypropylene nanocomposites containing 4wt% of maleic anhydride grafted polypropylene (MAH‐g‐PP) compatibilizer and different nanotube loadings. The effect of each screw configuration and nanotube loading on the tensile, rheological, and electrical properties of the nanocomposites were studied. The screw configurations were found to have a strong influence on the electrical resistivity while only slightly affected the tensile properties of the nanocomposites. Scanning electron microscopy examinations showed that the use of screw configuration consisting of kneading elements promoted the dispersion of nanotubes and resulted in a low electrical percolation at 2wt% of MCNT.