Derivatives of 4,4'-azobis-4-cyanopentanoic acid were prepared using its diacid chloride and various hydroxyl and amino compounds. The objective was to obtain substances that would act both as initiators for different modes of free-radical polymerisation and also as stabilisers for emulsion polymerisation reactions carried out in the absence of added conventional surfactant. During the preparation of the above compounds, it was discovered that 4,4'-azobis-4-cyanopentanoyl chloride appears to exist in two different forms called I and II. These forms yielded two different forms of esters when reacted with straight-chain aliphatic alcohols. These esters are called 'esters A' and 'esters B', respectively. Surprisingly, the esters A were found to act as effective initiator/stabilisers for the emulsion polymerisation of styrene in the absence of conventional surfactant. Unfortunately, during the course of the investigation, it was suddenly found to be impossible to prepare further batches of acid chloride I, and most subsequent attempts to prepare acid chloride I met with failure. The efforts which had been made to try to prepare acid chloride I and to elucidate possible structural differences between I and II that might account for the observed phenomena are described in detail. The rest of this work is concerned with the study of the behaviour of esters derived from acid chloride II and a range of fatty-alcohol ethoxylates. Results are given for the use of these derivatives as both initiators and stabilisers for the emulsion polymerisation of styrene in the absence of added conventional surfactant. The effects of temperature, initiator concentration and the total volume of water upon the rate of polymerisation were studied. Also, the effects of these variables upon the shapes of the conversion-versus-time curves obtained when the esters were used as initiator/stabilisers were investigated. The surfactant properties of some of the initiator/stabilisers have also been investigated. The kinetics of the decomposition of these initiator/stabilisers is also included.

A fracture mechanics study has been carried out on the fracture of rubber by cylindrical indentors. Several phenomena have been identified which affect the puncture process. It has been observed that a ring crack forms on the rubber surface before puncture occurs. By treating this crack as a starter crack, an equation has been derived for the puncture energy. The values of puncture energy so obtained were found to agree well with the catastrophic tearing energy obtained from the trouser tear test. The energy stored in the rubber influenced the value of the puncture energy calculated. The energy beneath the indentor was determined using a model experiment based on the biaxial stretching of rubber by inflation. The energy stored in the rubber surrounding the indentor was calculated. The contribution of these energies was shown to be small. The puncture test was used to study the strength of thick rubber blocks which had been exposed to long-term ageing and to high temperatures. These rubber blocks were taken from rubber bearings of 20 and 96 years of age respectively. A study was also carried out on a natural rubber tyre after forty two years immersion in sea water.

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Cellular manufacturing is widely viewed as an exemplary form of manufacturing organisation for small batch size production. A UK survey states that over 75% of British engineering industry have introduced or are planning to introduce cellular manufacturing methods in an attempt to improve competitiveness through improved product quality, responsiveness and flexibility (Ingersoll Engineers, 1990). Cells are known to foster these improvements through a focus on the methods of production and more co-operative work structures. The widespread adoption of cellular manufacturing methods has warranted research into and practical application of human-centred forms of work organisation. This approach seeks to improve the use of people and technology to develop more robust and effective manufacturing systems. The human-centred approach to job design and systems development is considered essential for improving Europe's future competitiveness (EC MONITOR FAST Programme, 1989-1992). The design of cellular manufacturing systems is a complex task involving the joint consideration of material flow, machines, people and control issues. The development and practice of human-centred job design in ceRs is an area with little formal process. There is no coherent academic model that embraces all the relevant issues in cell job design. This research develops and validates a generic model to facilitate human-centred job redesign in cell systems. The model adopts an open systems perspective and unifies three fields of job design embracing socio-technical, work organisation and function allocation issues. These levels provide a structure for the model. The model explicitly represents factors affecting job design by features defined at the three levels of analysis. The features are comprehensive and are representative of the issues encountered in each field of job design. The features are not independent and are interelated between levels of analysis. The model describes in quantitative terms the relationships between these features to provide a means for stepping through the cumulative effects of job design changes from one level to the next. An application procedure to use the model, derived from the research methodology in this thesis, is described outlining the data capture and analysis activities for developing situation sensitive pictures of cell job designs. The combined model and application procedure are tools to help the model users accumulate knowledge on the factors affecting the design of jobs in cells. Field research was carried out in a British manufacturing company over a period of fifteen months to develop and validate the model. CeH job design models were developed for four dissimilar cell systems varying in terms of cell age, work organisation and technical complexity. The model demonstrates its generalisability and sensitivity by accurately describing job design in four cell systems.

In the competitive field of metalworking industry, the planning of manufacturing systems so as to maximise their performance is crucial. The relatively new field of Flexible Manufacturing Systems presents a new set of planning challenges to the production engineer. This is due to the integrated nature of the these systems and the resultant effects upon their performance. This thesis presents a structured approach to the planning of materials flow within these systems and develops it by the analysis of several proposed manufacturing systems. The approach is based upon the use of mathematical and discrete event simulation techniques. The thesis gives the background to the need for a structured approach, investigates the parallel development of simulation languages and related techniques as applied to manufacturing facilities planning; and of the Flexible Manufacturing Systems themselves. The approach is then detailed and some specific types of planning tool are identified as suitable for use at each project stage. The effects upon the system of the integration of separate units, especially in low work in progress environments, are discussed in some detail. The methodology developed is then used in the context of three projects, specifically developing the theme of automated tool handling and the requirements that it places upon other aspects of a manufacturing system. The projects cover the analysis of pooling strategies, a key factor in determining tool magazine sizes and handling capacity/frequency demands; an academic analysis of a system with both component and tool handling systems; and an advanced Flexible Manufacturing System, also with both automated component and tool handling, which is currently being installed. Conclusions are presented at each stage, and these are drawn together to form a foundation for the planning of materials flow within Flexible Manufacturing Systems in general. Finally, suggestions are made for future work to develop the analysis.

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Made available in DSpace on 2014-10-09T12:37:46Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:12Z (GMT). No. of bitstreams: 1 05298.pdf: 2728793 bytes, checksum: bd666bab4f8ed34cf76b4702d3b8e1e0 (MD5) / Dissertacao (Mestrado) / IPEN/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

Two different factors involved in the measurement of photogrammetric plates have been studied. A novel interferometer designed to monitor the position of a microscope stage, to be used to measure photogrammetric plates, has been built. The prototype instrument is able to give the position of the stage with a maximum error of less than 200nm. An algorithm has been developed for a motor driven x-y microscope that is able to search a photographic plate automatically for targets, and record their positions. In a trial survey this system was able to measure the positions of the targets on the plates with an uncertainty of approximately 2gm. This result is comparable with the precision that a human operator could achieve using the same equipment, but without the fatigue effect associated with visual observation. Virtually no human interaction is necessary for the system to function.

The work presented in this thesis attempts to improve the performance of industrial robot systems in a flexible manufacturing environment by addressing a number of issues related to external sensory feedback and sensor integration, robot kinematic positioning accuracy, and robot dynamic control performance. To provide a powerful control algorithm environment and the support for external sensor integration, a transputer based open architecture robot controller is developed. It features high computational power, user accessibility at various robot control levels and external sensor integration capability. Additionally, an on-line trajectory adaptation scheme is devised and implemented in the open architecture robot controller, enabling a real-time trajectory alteration of robot motion to be achieved in response to external sensory feedback. An in depth discussion is presented on integrating a stereo vision sensor with the robot controller to perform external sensor guided robot operations. Key issues for such a vision based robot system are precise synchronisation between the vision system and the robot controller, and correct target position prediction to counteract the inherent time delay in image processing. These were successfully addressed in a demonstrator system based on a Puma robot. Efforts have also been made to improve the Puma robot kinematic and dynamic performance. A simple, effective, on-line algorithm is developed for solving the inverse kinematics problem of a calibrated industrial robot to improve robot positioning accuracy. On the dynamic control aspect, a robust adaptive robot tracking control algorithm is derived that has an improved performance compared to a conventional PID controller as well as exhibiting relatively modest computational complexity. Experiments have been carried out to validate the open architecture robot controller and demonstrate the performance of the inverse kinematics algorithm, the adaptive servo control algorithm, and the on-line trajectory generation. By integrating the open architecture robot controller with a stereo vision sensor system, robot visual guidance has been achieved with experimental results showing that the integrated system is capable of detecting, tracking and intercepting random objects moving in 3D trajectory at a velocity up to 40mm/s.