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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Corrosion of zinc in the automotive environment ‐ Relation Between Corrosion Rate, Corrosion Products and Exposure Site

Jonsson, Sanna January 2012 (has links)
In a previous project, mobile exposures in road environments have been performed in various areas of the world. A number of materials and coatings have been attached under trailers which travels long distances in different types of road environments. One of the materials, zinc, demonstrated various corrosion rates in different parts of the world. In this investigation two various accelerated corrosion tests have been performed at the laboratory of Swerea Kimab in order to realize parameter influence on zinc. Even though the corrosion rates are known, the relation to formed corrosion products has not been investigated earlier. In the present study, corrosion products on zinc have been analyzed using XRD and FTIR. The results from analyses of formed corrosion products have been evaluated together with measured corrosion rates, both from the mobile exposure and the accelerated tests, in order to try to understand under what conditions certain corrosion products are formed and how it affects the corrosion rate. A cold humid climate was found to be the most corrosive. In these environments, de ‐icing salts are used which promotes formation of Simonkolleite and in a subsequent step; Gordaite (if there is a not negligible deposition rate of SO2/SO42‐) which is often observed as the end product in marine environments.
2

Sustainability of quality improvement programmes in a heavy engineering manufacturing environment : a system dynamics approach

Van Dyk, Johannes Dirk January 2013 (has links)
Companies realize to stay competitive they have to introduce quality improvement programs. Many companies are challenged today with the sustainability of these quality improvement programs. Generally the understanding of the dynamic behaviour of quality improvement programs is poorly understood with soft issues as factors of the system. System dynamics may solve this problem. This research was focussed on operational management of operations. The organising framework of this research has been qualitative research where the research design was a polar type research design where the case studies focussed on initiatives that were dramatic success or failures, with the expectation that their comparison would help identify those processes that prevent competence enhancing change. A dynamic hypothesis has been constructed from archival data, semi-structured interviews and direct observations, gathered during these case studies. A system dynamics model for quality improvement programs in an automotive environment has been tested and expanded to be applicable for a heavy engineering manufacturing environment. The structure of the system dynamics model has been expanded to include a sustainability feedback loop which also included a management support model. The management support model included soft factors such as management support, management pressure and managerial effectiveness. The complete quality improvement program system dynamics simulation model with sustainability has been tested and validated against a real system data, for a heavy engineering manufacturing environment, gathered during the case studies. The model parameters were determined from a calibration algorithm, by using the Vensim® simulation platform, that fitted the real system behaviour the best. A sensitivity analysis has been done on the model parameters determining the information cues for the management decision policies. From the system dynamics model of the complete quality improvement program, including the sustainability feedback loop, proposed management decision policies have been studied that could lead to sustainable quality improvement programs for a heavy engineering manufacturing environment. From these simulation studies several management policies have been proposed. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Graduate School of Technology Management / Unrestricted
3

Analýza a optimalizace procesu výroby vývojových vzorků / Analyse and Optimise Production Process of Prototypes

Hamr, Tomáš January 2019 (has links)
This diploma thesis summarizes basic findings about issues of making development samples of PCB. The emphasis is especially on required quality which complies with mentioned norms. The theoretical section includes methodology for evaluating quality dismounted boards, assembling and soldering, parameters of components under different environmental circumstances. The practical part is carried out in cooperation with the department EEG in R&D Automotive Lighting Jihlava. It is dedicated to the design and the preparation of development samples where the quality is assessed according to given methodology from the theoretical part. PCB are analyzed by an X-ray, metallographic grinding and other methods. Recommendations are given and based on results for improvements.

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