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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.
31

Aspects of design for a spare parts provisioning system

Love, Douglas M. January 1980 (has links)
This thesis describes an investigation by the author into the spares operation of compare BroomWade Ltd. Whilst the complete system, including the warehousing and distribution functions, was investigated, the thesis concentrates on the provisioning aspect of the spares supply problem. Analysis of the historical data showed the presence of significant fluctuations in all the measures of system performance. Two Industrial Dynamics simulation models were developed to study this phenomena. The models showed that any fluctuation in end customer demand would be amplified as it passed through the distributor and warehouse stock control systems. The evidence from the historical data available supported this view of the system's operation. The models were utilised to determine which parts of the total system could be expected to exert a critical influence on its performance. The lead time parameters of the supply sector were found to be critical and further study showed that the manner in which the lead time changed with work in progress levels was also an important factor. The problem therefore resolved into the design of a spares manufacturing system. Which exhibited the appropriate dynamic performance characteristics. The gross level of entity presentation, inherent in the Industrial Dynamics methodology, was found to limit the value of these models in the development of detail design proposals. Accordingly, an interacting job shop simulation package was developed to allow detailed evaluation of organisational factors on the performance characteristics of a manufacturing system. The package was used to develop a design for a pilot spares production unit. The need for a manufacturing system to perform successfully under conditions of fluctuating demand is not limited to the spares field. Thus, although the spares exercise provides an example of the approach, the concepts and techniques developed can be considered to have broad application throughout batch manufacturing industry.
32

Some aspects of the dynamic performance of machine tool structural joints

Shoukry, Samir N. January 1980 (has links)
The work presented in this thesis is concerned with the dynamic behaviour of structural joints which are both loaded, and excited, normal to the joint interface. Since the forces on joints are transmitted through their interface, the surface texture of joints was carefully examined. A computerised surface measuring system was developed and computer programs were written. Surface flatness was functionally defined, measured and quantised into a form suitable for the theoretical calculation of the joint stiffness. Dynamic stiffness and damping were measured at various preloads for a range of joints with different surface textures. Dry clean and lubricated joints were tested and the results indicated an increase in damping for the lubricated joints of between 30 to 100 times. A theoretical model for the computation of the stiffness of dry clean joints was built. The model is based on the theory that the elastic recovery of joints is due to the recovery of the material behind the loaded asperities. It takes into account, in a quantitative manner, the flatness deviations present on the surfaces of the joint. The theoretical results were found to be in good agreement with those measured experimentally. It was also found that theoretical assessment of the joint stiffness could be carried out using a different model based on the recovery of loaded asperities into a spherical form. Stepwise procedures are given in order to design a joint having a particular stiffness. A theoretical model for the loss factor of dry clean joints was built. The theoretical results are in reasonable agreement with those experimentally measured. The theoretical models for the stiffness and loss factor were employed to evaluate the second natural frequency of the test rig. The results are in good agreement with the experimentally measured natural frequencies.
33

A heat metering system for energy management on an industrial site

Roberts, Martin January 1985 (has links)
Faced with a future of rising energy costs there is a need for industry to manage energy more carefully in order to meet its economic objectives. A problem besetting the growth of energy conservation in the UK is that a large proportion of energy consumption is used in a low intensive manner in organisations where they would be responsibility for energy efficiency is spread over a large number of personnel who each see only small energy costs. In relation to this problem in the non-energy intensive industrial sector, an application of an energy management technique known as monitoring and targeting (M & T) has been installed at the Whetstone site of the General Electric Company Limited in an attempt to prove it as a means for motivating line management and personnel to save energy. The objective energy saving for which the M & T was devised is very specific. During early energy conservation work at the site there had been a change from continuous to intermittent heating but the maintenance of the strategy was receiving a poor level of commitment from line management and performance was some 5% - 10% less than expected. The M & T is concerned therefore with heat for space heating for which a heat metering system was required. Metering of the site high pressure hot water system posed technical difficulties and expenditure was also limited. This led to a ‘tin-house' design being installed for a price less than the commercial equivalent. The timespan of work to achieve an operational heat metering system was 3 years which meant that energy saving results from the scheme were not observed during the study. If successful the replication potential is the larger non energy intensive sites from which some 30 PT savings could be expected in the UK.
34

Some strategies for improving the present state of quality control methods in Venezuelan metalworking industries

Morillo, Gerardo Z. January 1981 (has links)
The title of this thesis seeks to indicate its objective. In fact, it is basically intended to explore the problems that arise from designing, developing and introducing Quality Control (QC) systems in the Venezuelan metalworking industry and to examine the method by which managers deal with such problems. Particular attention is given to the analysis of the quality problems in the smaller industries. Due mainly to the interdisciplinary and complex nature of the research project undertaken - in which a comprehensive study was made of the interrelations and constraints of the technical, human and economic factors in the design of a national strategy on quality - it was found appropriate to adopt the "systems approach" in this study. Firstly, it was applied to define QC as an integral part of Production Management and secondly, to formulate some strategies on quality in the Venezuelan metalworking sector. Apart from the lack of quality consciousness, adequate educational and training programmes, skilled manpower, shortage of energy and other natural and financial resources, among others, the choice of technology is the most critical problem facing any developing country. After analysing the appropriateness of the concept of Intermediate Technology (which in essence is that the increasing, complex, highly sophisticated, capital-intensive, large-scale and labour eliminating technologies of the highly industrialized countries are generally inappropriate for many developing countries) as a means to pursue industrialization in developing nations, it is argued that a new approach is needed in order to meet the new demands and to establish an effective and economic control of quality of manufactured products, which are obtained by using such technologies. The practical implications of the term 'Intermediate Quality Control' are discussed, and later it is shown that in most of the cases this quality technology stands between inspection-orientated QC and total QC. On the basis of such analytical study, and also taking into consideration the results of a field work study carried out by the author in Venezuela, some recommendations are made on the appropriate aims and content of management QCimprovements and development strategies for raising the level of quality in Venezuelais manufacture and production.
35

Some aspects of an integrated manufacturing system

Farkas, Jules January 1979 (has links)
No description available.
36

Capture and storage of respiratory test data

Cheah, Ui P. January 1982 (has links)
No description available.
37

Dressing of grinding wheels for high rate of metal removal

Fielding, Edward R. January 1982 (has links)
No description available.
38

Investigations into long-term productivity improvements in an automotive rubber concern

Green, Nicholas C. H. January 1978 (has links)
No description available.
39

Energy absorbed in impact extrusion

Leavesley, Peter J. January 1978 (has links)
No description available.
40

The mechanics of drawing wire at elevated temperatures

Loh, Ngiap H. January 1983 (has links)
No description available.

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