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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.
181

Microstructure characterization and corrosion properties of two recycled aluminium alloys AA5050 and AA6011

Jordan, Aaron January 2017 (has links)
The influence of recycling on aluminium alloys and subsequent influence on the microstructure and corrosion performances have been investigated. The investigation was commenced by taking two block cast, recycled aluminium alloys (AA5050 and AA6011) and rolling them into 1mm gauge plate. In the case of AA6011, the plate was subjected to subsequent solution heat treatment and artificial aging steps, in order to attain certain temper specifications. To replicate the automotive paint bake industrial practice, a sample was subjected to a 2% tensile stretch followed by heat treatment for 30 minutes at 180˚C. Microstructural observations revealed Al-Fe-Mn-Si intermetallics to be the dominant secondary phase in both alloys. The size, distribution and composition of these were unaffected by artificial aging. Mg2Si was found in a coarse, localised form in both alloys also, albeit in much less amounts in AA5050. The presence of this phase was likely due to poor homogenisation during thermomechanical processing. HR-TEM of AA6011 revealed needle/rod shaped precipitates, aligning in the [001]Al lattice direction. This is consistent with β''/β' hardening precipitates consisting of magnesium and silicon. Circumstantial evidence was found for the copper-containing Q phase precipitate also. An additional, unidentified precipitate was observed, nucleating on the {111} habit plane of the aluminium matrix. The high iron content of AA6011 retarded the precipitation hardening response by capturing elements associated with hardening precipitates in the Al-Fe-Mn-Si intermetallics. Electrochemical corrosion experiments revealed the materials had a high susceptibility to localised corrosions, with the open circuit potential and breakdown potential possessing similar values. Atmospheric corrosion experiments showed that artificial aging had a large influence on the preferred corrosion mechanism. Non-heat treated samples showed susceptibility for pitting corrosion. This was particularly true for the -T4P temper, which showed large scale pitting. Heat treated samples saw an introduced susceptibility to intergranular corrosion. This was attributed to precipitation at grain boundaries, which would then form a microgalvanic couple with adjacent depleted zones. In the case of the -T8P temper, tensile stretching introduced defects into the sub-grain microstructure. This resulted in intergranular corrosion fronts of increased width, where grains with higher stored energy undergo preferential dissolution alongside the grain boundary attack. Overall, the detrimental effects of high iron content need to be overcome before AA5050 and AA6011 can be seriously considered for use in the automotive industry. However, the corrosion performance of AA6011-T8P is encouraging.
182

Integration of machinery condition monitoring and reliability modeling: A prelude to predictive maintenance

Unknown Date (has links)
Condition Based Maintenance (CBM) is a philosophical approach that uses the most cost effective methodology for the performance of machinery maintenance. The idea is to ensure maximum operational life and minimum downtime of machinery within predefined cost, safety and availability constraints. When machinery life extension is a major consideration the CBM approach usually involves predictive maintenance. In this research a two-level approach for predictive maintenance has been defined: (1) to develop a Condition Monitoring and Diagnostic System (CMDS) for machine fault detection and maintenance suggestion, and (2) to develop a machine performance estimation model for machine reliability modeling and failure rate analysis. The objective is to provide a new and practicable solution for condition-based predictive maintenance. / In this research artificial neural network (ANN) technologies and analytical models have been investigated and incorporated to increase the effectiveness and efficiency of CMDS. Several advanced vibration trending methods have been studied and used to quantify machine operating conditions. An on-line, multi-channel condition monitoring procedure has been developed and coded. The major technique used for fault diagnostics is a modified ARTMAP neural network. In the second part of this research a new method of obtaining maintenance information has been developed. A Cerebellar Model Articulation Controller (CMAC) neural network has been employed to estimate and quantify machine performance. By combining reliability theory with a real-time, on-line CMAC Performance Estimation Model (CMAC-PEM), machine reliability statistics such as failure rate and mean time between failures (MTBF) can be calculated. CMAC-PEM may provide a practicable solution for condition-based predictive maintenance since it estimates machine reliability measures on-line. In addition, Weibull Proportional Hazards Model (WPHM), has been implemented as a proven tool to verify CMAC-PEM results. Real-world data obtained from a bearing fault experiment and a bearing deterioration process were provided to test the proposed methodologies. / Essentially, this research presents an innovative method to synthesize low level information, such as vibration signals, with high level information, like reliability statistics, to form a rigorous theoretical base for condition-based predictive maintenance. / Source: Dissertation Abstracts International, Volume: 56-04, Section: B, page: 2251. / Major Professor: Hsu-Pin (Ben) Wang. / Thesis (Ph.D.)--The Florida State University, 1995.
183

The ecological modernisation of industry : developing multi-disciplinary research in organization & environment.

Orssato, Renato J. January 2001 (has links)
This thesis develops suitable approaches to conduct environment-related research in organisations, as well as systematic means for understanding the emergent phenomenon of ecological modernisation in industrialised societies. The study is organised in two distinct parts: While Part I deals with environment-related theories and practices in (and around) modern organisations, Part II situates such theories and practices in an analysis of the context of the European automobile industry. The research problem is defined through several stages. The research questions driving Part I are premised on the exploratory nature of the study, developed in an unfolding interplay between the review of the literature, the collection of secondary and (exploratory) primary data, and the analysis and interpretation of the data. As the initial question is answered by reviewing the literature and interpreting the primary and secondary data, another question arises from the process, which then requires further research. Part II of the study departs from a proposition based on ecological modernisation theory, that pro-active environmental practices in corporations are part of a broader emergent sociological phenomenon, typical of modern industrialised societies. It analyses a specific socio-technical context that, hypothetically, is undergoing such process - that of the European automobile industry. Hence, the development of Part II aims at answering the following principal research question: Why is the European automobile industry undergoing ecological modernisation? Analytically, the concept of automobile field is proposed to establish a link between the product (automobile) and the context embedding its systems of production and consumption (field). The exploratory character of the study implied that the most adequate research procedures were of a qualitative nature. A combination of grounded theory and reflexive methodology is used to orientate the overall research process, which introduces a novel approach for the triangulation of qualitative data. Together, the chapters forming Part II of the thesis answer the principal research question. The fundamental technologies of the current technological regime of the automobile, as well as the economic and environmental implications of this regime are analysed. Then, an analysis of selected pilot programs to develop and commercialise electric vehicles, as well as schemes for the management of end-of-life vehicles in the Western European context is developed. Through the interplay between data collection and analysis, the thesis designs an analytical framework, built upon contingent factors, as well as circuits of political ecology, that foster or inhibit ecological modernisation in the automobile field. The study showed that the auto industry has developed incremental technological innovations and practices that resemble the pre-requisites for ecological modernisation. Radical innovations, however, are more likely to be initiated by outsiders. The concepts inherited from the past and reproduced in the present practice of car design explains such a situation as one that imposes a specific set of technologies on car manufacturing that require high levels of investment in systems of production. Such design paradigm not only imposes high break-even points for most car models; they also result in vehicles with extremely low environmental performance and entail serious limitations for increasing recycling rates of non-metallic parts. The characteristics of ecological modernisation in the European automobile industry are used to evaluate whether this phenomenon is conducive to sustainable industrial development. As an implication of this analysis, the concluding chapter presents suggestions for the enhancement of ecological modernisation theory. Fallibility is proposed as both a source of reflection about the appropriation of knowledge and a principle that can be used for the definition of eco-modernising strategies and actions. The acceptance of fallibility as an immanent characteristic of human action is critical for the approximation of the countervailing theories of ecological modernisation and risk society. Finally, if ecological modernisation is expected to facilitate sustainable industrial development, radical technological innovations may be necessary. Such radicalism in technology may need, however, an incremental institutional reform of modern societies. Together, radical technological innovations and incremental institutional reform constitute the concept of radical reformism, which is suggested for enhancement of the ecological modernisation theory, as well as for the development of its normative programmes.
184

The ecological modernisation of industry : developing multi-disciplinary research in organization & environment.

Orssato, Renato J. January 2001 (has links)
This thesis develops suitable approaches to conduct environment-related research in organisations, as well as systematic means for understanding the emergent phenomenon of ecological modernisation in industrialised societies. The study is organised in two distinct parts: While Part I deals with environment-related theories and practices in (and around) modern organisations, Part II situates such theories and practices in an analysis of the context of the European automobile industry. The research problem is defined through several stages. The research questions driving Part I are premised on the exploratory nature of the study, developed in an unfolding interplay between the review of the literature, the collection of secondary and (exploratory) primary data, and the analysis and interpretation of the data. As the initial question is answered by reviewing the literature and interpreting the primary and secondary data, another question arises from the process, which then requires further research. Part II of the study departs from a proposition based on ecological modernisation theory, that pro-active environmental practices in corporations are part of a broader emergent sociological phenomenon, typical of modern industrialised societies. It analyses a specific socio-technical context that, hypothetically, is undergoing such process - that of the European automobile industry. Hence, the development of Part II aims at answering the following principal research question: Why is the European automobile industry undergoing ecological modernisation? Analytically, the concept of automobile field is proposed to establish a link between the product (automobile) and the context embedding its systems of production and consumption (field). The exploratory character of the study implied that the most adequate research procedures were of a qualitative nature. A combination of grounded theory and reflexive methodology is used to orientate the overall research process, which introduces a novel approach for the triangulation of qualitative data. Together, the chapters forming Part II of the thesis answer the principal research question. The fundamental technologies of the current technological regime of the automobile, as well as the economic and environmental implications of this regime are analysed. Then, an analysis of selected pilot programs to develop and commercialise electric vehicles, as well as schemes for the management of end-of-life vehicles in the Western European context is developed. Through the interplay between data collection and analysis, the thesis designs an analytical framework, built upon contingent factors, as well as circuits of political ecology, that foster or inhibit ecological modernisation in the automobile field. The study showed that the auto industry has developed incremental technological innovations and practices that resemble the pre-requisites for ecological modernisation. Radical innovations, however, are more likely to be initiated by outsiders. The concepts inherited from the past and reproduced in the present practice of car design explains such a situation as one that imposes a specific set of technologies on car manufacturing that require high levels of investment in systems of production. Such design paradigm not only imposes high break-even points for most car models; they also result in vehicles with extremely low environmental performance and entail serious limitations for increasing recycling rates of non-metallic parts. The characteristics of ecological modernisation in the European automobile industry are used to evaluate whether this phenomenon is conducive to sustainable industrial development. As an implication of this analysis, the concluding chapter presents suggestions for the enhancement of ecological modernisation theory. Fallibility is proposed as both a source of reflection about the appropriation of knowledge and a principle that can be used for the definition of eco-modernising strategies and actions. The acceptance of fallibility as an immanent characteristic of human action is critical for the approximation of the countervailing theories of ecological modernisation and risk society. Finally, if ecological modernisation is expected to facilitate sustainable industrial development, radical technological innovations may be necessary. Such radicalism in technology may need, however, an incremental institutional reform of modern societies. Together, radical technological innovations and incremental institutional reform constitute the concept of radical reformism, which is suggested for enhancement of the ecological modernisation theory, as well as for the development of its normative programmes.
185

The ecological modernisation of industry : developing multi-disciplinary research in organization & environment.

Orssato, Renato J. January 2001 (has links)
This thesis develops suitable approaches to conduct environment-related research in organisations, as well as systematic means for understanding the emergent phenomenon of ecological modernisation in industrialised societies. The study is organised in two distinct parts: While Part I deals with environment-related theories and practices in (and around) modern organisations, Part II situates such theories and practices in an analysis of the context of the European automobile industry. The research problem is defined through several stages. The research questions driving Part I are premised on the exploratory nature of the study, developed in an unfolding interplay between the review of the literature, the collection of secondary and (exploratory) primary data, and the analysis and interpretation of the data. As the initial question is answered by reviewing the literature and interpreting the primary and secondary data, another question arises from the process, which then requires further research. Part II of the study departs from a proposition based on ecological modernisation theory, that pro-active environmental practices in corporations are part of a broader emergent sociological phenomenon, typical of modern industrialised societies. It analyses a specific socio-technical context that, hypothetically, is undergoing such process - that of the European automobile industry. Hence, the development of Part II aims at answering the following principal research question: Why is the European automobile industry undergoing ecological modernisation? Analytically, the concept of automobile field is proposed to establish a link between the product (automobile) and the context embedding its systems of production and consumption (field). The exploratory character of the study implied that the most adequate research procedures were of a qualitative nature. A combination of grounded theory and reflexive methodology is used to orientate the overall research process, which introduces a novel approach for the triangulation of qualitative data. Together, the chapters forming Part II of the thesis answer the principal research question. The fundamental technologies of the current technological regime of the automobile, as well as the economic and environmental implications of this regime are analysed. Then, an analysis of selected pilot programs to develop and commercialise electric vehicles, as well as schemes for the management of end-of-life vehicles in the Western European context is developed. Through the interplay between data collection and analysis, the thesis designs an analytical framework, built upon contingent factors, as well as circuits of political ecology, that foster or inhibit ecological modernisation in the automobile field. The study showed that the auto industry has developed incremental technological innovations and practices that resemble the pre-requisites for ecological modernisation. Radical innovations, however, are more likely to be initiated by outsiders. The concepts inherited from the past and reproduced in the present practice of car design explains such a situation as one that imposes a specific set of technologies on car manufacturing that require high levels of investment in systems of production. Such design paradigm not only imposes high break-even points for most car models; they also result in vehicles with extremely low environmental performance and entail serious limitations for increasing recycling rates of non-metallic parts. The characteristics of ecological modernisation in the European automobile industry are used to evaluate whether this phenomenon is conducive to sustainable industrial development. As an implication of this analysis, the concluding chapter presents suggestions for the enhancement of ecological modernisation theory. Fallibility is proposed as both a source of reflection about the appropriation of knowledge and a principle that can be used for the definition of eco-modernising strategies and actions. The acceptance of fallibility as an immanent characteristic of human action is critical for the approximation of the countervailing theories of ecological modernisation and risk society. Finally, if ecological modernisation is expected to facilitate sustainable industrial development, radical technological innovations may be necessary. Such radicalism in technology may need, however, an incremental institutional reform of modern societies. Together, radical technological innovations and incremental institutional reform constitute the concept of radical reformism, which is suggested for enhancement of the ecological modernisation theory, as well as for the development of its normative programmes.
186

<em>Key Challenges in Decision Making for Automotive E/E Architectures</em>

Wallin, Peter January 2008 (has links)
<p><p>The amount of electronics in vehicles is growing quickly, thus systems are becoming increasingly complex making the engineering of these software intensive systems more and more difficult. In particular, an architecture supporting the business goals is a prerequisite for successful design.</p><p>In this thesis two case studies have been made including three automotive companies with purpose to investigate the key issues related to real-world decisions when developing Electrical and Electronic (E/E) system architectures in the automotive industry.</p><p>The results show that many of the identified issues relate to non technical areas such as organization, process, methods and tools, and management. Examples of identified issues are the deficient understanding of the electrical system and software at management level, and the lack of a specific process for architecture development. To cope with these issues we suggest the following actions: Educate management, increase the use of structured decision making, improve the architecture development process, clarify responsibilities in the organization and clarify development strategies.</p><p>As a possible solution to one of the suggested actions we have developed a method to evaluate how new functionality is successfully integrated into an existing architecture. Themethod is a combination of the Architecture Tradeoff Analysis Method, ATAM, and the Analytical Hierarchy Process, AHP. The method firstly supports a structured way of listing system goals, and secondly, it also supports the making of design decisions.</p></p> / Business Oriented Concept Development of Electronic System Architecture and Platforms in Vehicles
187

In Search of Maintaining Competitiveness through Industry Analysis- The case of the rubber subcontractors in the automotive industry

Draoui, Sohail, Liu, Yifei January 2007 (has links)
<p>With the purpose of expanding our understanding on the main causes that make maintaining competitiveness a challenging issue for companies in an industry, a qualitative research is conducted in this thesis based on Porter theoretical framework (i.e. the five competitive forces model); thereby selecting a single case study with a Swedish rubber subcontractor. The findings show that the threat of new entrants, the rivalry among the existing rubber subcontractors, the bargaining power of carmakers, the bargaining power of suppliers and the role of the Swedish government all highly concern and challenge the competitiveness of the case company. However, given the fact that close substitute products to the case company’s product are absent from the market, their threat does not represent any distress for the competitiveness of the company.</p>
188

In Search of Maintaining Competitiveness through Industry Analysis- The case of the rubber subcontractors in the automotive industry

Draoui, Sohail, Liu, Yifei January 2007 (has links)
With the purpose of expanding our understanding on the main causes that make maintaining competitiveness a challenging issue for companies in an industry, a qualitative research is conducted in this thesis based on Porter theoretical framework (i.e. the five competitive forces model); thereby selecting a single case study with a Swedish rubber subcontractor. The findings show that the threat of new entrants, the rivalry among the existing rubber subcontractors, the bargaining power of carmakers, the bargaining power of suppliers and the role of the Swedish government all highly concern and challenge the competitiveness of the case company. However, given the fact that close substitute products to the case company’s product are absent from the market, their threat does not represent any distress for the competitiveness of the company.
189

VEVA Multifunctional Spindlering

Pettersson, Simon, Miranda, Andersson January 2013 (has links)
Our thesis is made in collaboration with Autoliv Sweden and the department Global Development Seatbelt in Vårgårda. Autoliv was founded in 1953 by two brothers from Vårgårda. Since then, they have become world leading in automotive safety and cooperates with several major automotive companies.   The aim of the project was to evaluate a concept that Adrian Bud for Global Development Seatbelt department in Vårgårda had come up with. The concept aims to simplify the design and reduce the number of parts in an adaptive load limiter (LLA). With a reduction in the number of parts, the price for the LLA would decrease and also make assembly easier.   An LLA adjusts the chest compression from the seatbelt in a crash sequence. This helps reducing the injury that might result from such chest compressions in a crash. The load limiter ensures that the slowdown of the body is done in a smooth manner by adjusting the amount of belt released.   Our concept evaluation has included conceptual design, primary design, visualization of design in Catia V5 and FEM analysis. Finally prototypes were built with the help of Autolivs central workshop and tests were performed at Autoliv. The report also includes analyzes of the results, recommendations for the continuation of work and development and a critical review of the evaluation.
190

A System Level FMCW RADAR Optimization For Automotive Powertrain Control Application Requirements

Beg, Christopher 22 January 2013 (has links)
A full system level analysis, design, and ealization of frequency-modulation / continuous-wave (FMCW) RADAR is presented in this thesis. RADAR technology has been around for over half a century, and has found itself in a wide range of applications effecting every day life. As such, there are many possible system level tradeoffs that can be made when designing a sensor for a specific application. This paper will focus on designing a sensor for a hybrid electric vehicle powertrain control unit, as part of a new application in fuel economy improvement. The system level analysis will derive a full baseband signal analysis model, and examine some of the commonly used modulation schemes. Next, a method for tuning the modulation waveform properties to optimize the sensor specifically for the application requirements is presented. Finally a system level realization is proposed to produce synchronous and streamlined processing of the signals, while providing flexibility to tune the implementation as suggested during the modulation waveform optimization. As a proof of concept, a hardware prototyping platform was designed and built to allow acquisition of real signals which are to be fed into a signal processing algorithm. The signal processing algorithm to decode the measurement results can then be developed effectively using real data. Some of the measurement results obtained with the prototyping platform and system optimizations suggested within this thesis are presented to verify the analysis and modeling performed.

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