The stability against coalescence of vegetable oil-in-water “food grade” emulsions in the presence of both surfactant and colloidal particles (hydrophilic silica) has been studied and compared to the stability of systems where only the surfactant or the colloidal particles act as the emulsifier. No attempt was made to stop the emulsions from creaming. Two types of surfactants were selected; those that have the ability to stabilise O/W emulsions on their own (O/W surfactants) and those that cannot (W/O surfactants). Tween 60 and Sodium Caseinate were selected as the O/W surfactants, monoolein and lecithin as the W/O surfactants. These mixed emulsifier systems were shown to induce long-term emulsion stability against coalescence, regardless of the surfactant type, via a synergistic “two-part” mechanism in which both the surfactant and colloidal particles components have specific functions. Nonetheless, the emulsion microstructure was proved to depend on the surfactant’s type and concentration: the use of O/W emulsifiers above a certain concentration induced a displacement of particles from the interface, while such a displacement was not observed using W/O emulsifiers. Further measurements of interfacial tension and contact angle showed that the level of adsorption of solid particles at the interface depended on the surfactant type and concentration.

There are lots of elements involved in the design of a car. This study, which is inspired by the brief of BMW group, explores the seating unit of cars with regard to prototypical activities, such as, listening to music, working, looking outside etc. The current study proposes that these external stimuli have an effect on comfort experience and felt emotions. So, this study explores the relationship between types of music and activities typically performed by car passengers and emotion and comfort perception, through performing a within subject design empirical study. A car seat provided by BMW group was used to test the above mentioned relationships. Data was collected through a self-report questionnaire, heart rate equipment, a pressure mat and analyzed separately for each condition. Results of the study show that there is a successful emotion induction by task and music individually, and partly on task*music interaction. A comparison of congruent and non-congruent situations, i.e. high arousal music and high arousal task or low arousal music and low arousal task, showed that differences occur in subjects&rsquo / reported level of arousal. Furthermore, the results of the study indicated that comfort is related to valance factors, independent of arousal levels. Lastly, physiological measurements showed that only task has a significant effect on heart rate, implicating for the complexity of linking physiological data to emotion and comfort.

Product design changes are inevitable in the current trend of time-based competition where product models such as automotive bodies and aircraft fuselages are frequently upgraded and cause assembly process design changes. In recent years, several studies in engineering change management and reconfigurable systems have been conducted to address the challenges of frequent product and process design changes. However, the results of these studies are limited in their applications due to shortcomings in three aspects which are: (i) They rely heavily on past records which might only be a few relevant cases and insufficient to perform a reliable analysis; (ii) They focus mainly on managing design changes in product architecture instead of both product and process architecture; and (iii) They consider design changes at a station-level instead of a multistation level. To address the aforementioned challenges, this thesis proposes three interrelated research areas to simulate the design adjustments of the existing process architecture. These research areas involve: (i) the methodologies to model the existing process architecture design in order to use the developed models as assembly response functions for assessing Key Performance Indices (KPIs); (ii) the KPIs to assess quality, cost, and design complexity of the existing process architecture design which are used when making decisions to change the existing process architecture design; and (iii) the methodology to change the process architecture design to new optimal design solutions at a multi-station level. In the first research area, the methodology in modeling the functional dependence of process variables within the process architecture design are presented as well as the relations from process variables and product architecture design. To understand the engineering change propagation chain among process variables within the process architecture design, a functional dependence model is introduced to represent the design dependency among process variables by cascading relationships from customer requirements, product architecture, process architecture, and design tasks to optimise process variable design. This model is used to estimate the level of process variable design change propagation in the existing process architecture design Next, process yield, cost, and complexity indices are introduced and used as KPIs in this thesis to measure product quality, cost in changing the current process design, and dependency of process variables (i.e, change propagation), respectively. The process yield and complexity indices are obtained by using the Stream-of-Variation (SOVA) model and functional dependence model, respectively. The costing KPI is obtained by determining the cost in optimizing tolerances of process variables. The implication of the costing KPI on the overall cost in changing process architecture design is also discussed. These three comprehensive indices are used to support decision-making when redesigning the existing process architecture. Finally, the framework driven by functional optimisation is proposed to adjust the existing process architecture to meet the engineering change requirements. The framework provides a platform to integrate and analyze several individual design synthesis tasks which are necessary to optimise the multi-stage assembly processes such as tolerance of process variables, fixture layouts, or part-to-part joints. The developed framework based on transversal of hypergraph and task connectivity matrix which lead to the optimal sequence of these design tasks. In order to enhance visibility on the dependencies and hierarchy of design tasks, Design Structure Matrix and Task Flow Chain are also adopted. Three scenarios of engineering changes in industrial automotive design are used to illustrate the application of the proposed redesign methodology. The thesis concludes that it is not necessary to optimise all functional designs of process variables to accommodate the engineering changes. The selection of only relevant functional designs is sufficient, but the design optimisation of the process variables has to be conducted at the system level with consideration of dependency between selected functional designs.

An uncertain environment has forced manufacturing systems to have flexibility. Uncertainties involved with internal and external factors means that flexibility becomes an important competitive factor for the firms. However, the concept of manufacturing flexibility has not yet been clearly identified, understood and integrated. These problems have led to researchers and practitioners getting confused and this produces difficulties when trying to implement it. The research in this thesis attempts to clarify and integrate the various aspects of manufacturing flexibility measurement. The objective of the research was to develop theoretical models to quantify the measurement with mathematical mechanisms. A consolidated and synthesized approach, defined as the attribute approach is proposed in this thesis. This leads to a unified framework for flexibility measurement. Vague concepts together with arbitrarily used terminology has led to confusion in concept and contradictions in manufacturing flexibility research. Omissions that appeared in the literature have been identified and remedied in this research. Ten types of flexibility attributes have been proposed and applied to six types of manufacturing flexibility. By exploring of all ten types of flexibility attribute, it has been possible to clarify the confused arguments found in the literature. The main advantage of the attribute approach is its thorough treatment of flexibility measurement. It has provided a conceptually understandable and theoretically precise method of measuring manufacturing flexibility. It also points to new directions for further research in this field. It is hoped that this thesis has pushed forward the frontier of knowledge in this field.

Manufacturing Systems are subject to increasingly frequent changes in demand in terms of number and type of products they produce. It is impractical to continually reconfigure the facilities, but it is possible to modify the material handling arrangements so that the selected equipment is the most appropriate for the current requirements. The number of decisions that need to be made coupled with the rate at which decisions must be taken adds significant difficulty to the problem of equipment selection. Furthermore there are relatively few experts who have the necessary range of knowledge coupled with the ability to use this knowledge to select the most appropriate material handling solution in any situation. Access to such experts is therefore greatly restricted and decisions are more commonly made by less experienced people, who depend on equipment vendors for information, often resulting in poor equipment selection. This research first examines the significance of appropriate material handling equipment choice in dynamic environments. The objective is to construct a computer based expert system utilising knowledge from the best available sources in addition to a systematic procedure for selection of material handling equipment. A new system has been produced, based on the Flex language, which elicits from the inexperienced user details of the handling requirements in order to build an equipment specification. It then selects from among 11 handling solution groups and provides the user with information supporting the selection. Original features of the system are the way in which the knowledge is grouped, the ability of the procedure to deal with quantifiable and non-quantifiable equipment and selection factors, selection of decision analysis method and the validation of the final choice to establish confidence in the results. The system has been tested using real industrial data and has been found in 81% of cases to produce results which are acceptable to the experts who provided the information.

This thesis reports on a case survey of 15 UK metalworking companies and their experience of implementing an integrating technology - CAD/CAM. The thesis places this process of implementation in the organisational context of these companies by examining the ways in which the engineering/manufacturing interface is coordinated. This interface is important, because it is also critical to the effective implementation of such techniques as total quality management and simultaneous engineering. In order to develop an incisive analysis of these companies, a contingency approach to organisational analysis is developed around the idea of flows of information and materials and their interaction with the structure of the organisation in a process of structuration. This analysis is placed in the strategic context of the organisations' relationships to their environment through the notion of a production strategy. Models of the process of implementation are then reviewed, and a recursive model of implementation as organisational changing is developed which emphasises the processes of organisational learning. The management of the engineering design process has been little examined, in comparison to the management of manufacturing, and research and development. This thesis develops an analysis of the management of the entire production process from the conception of the product right through to its delivery to the customer in these 15 firms. It then goes on to examine the recent organisational changes in the engineering and manufacturing functions before examining the implementation process in detail. Finally, the basis of organisational integration from both a technological and organisational perspective is analysed, which provides the basis for some more general propositions on the development of production management over the next decade.

This thesis seeks to establish a connection between abstract thought and material practice. It does so by focusing on the relation between the transcendental philosophy of time and the socio-technics of time-keeping practices. The thesis begins with a discussion of Kant's philosophy of time as outlined in the Critique of Pure Reason. It argues that Kant's discovery of the transcendental coincides with the development of an entirely new conception of time. This new conception overturns classical thought by making a distinction between the abstract form of time and the empirical phenomena of movement and change. The second chapter maps the transcendental philosophy of time on to the history of capitalist time-keeping. This history includes: the invention and development of the mechanical clock, temporal standardization and the increasing importance of the equation 'time = money. The aim in bringing these two spheres together is to show, both that Kant's philosophy of time owes much to his empirical surroundings, and also that capitalist time can only be understood through the temporal abstraction of transcendental thought. This link between Kant and capitalism is blocked, however, by a dividing line which separates the philosophical nature of time from the empirical changes of history. In order to surpass this problem the thesis turns to the work of Deleuze and Guattari whose 'transcendental materialism' connects the abstract production of time with empirical innovations. This is accomplished by replacing the classical conception of a transcendent eternity with the immanent materiality of an exterior plane. This plane - which they call Aeonis composed of thresholds, or singular events which make no distinction between time and that which occurs in time. The final chapter explores the dawn of the third millennium - or Y2K - as constituting one such Aeonic event.

Tolerance measure is an important part of engineering, however, to date the system of applying this important technology has been left to the assessment of the engineer using appropriate guidelines. This work offers a major departure from the trial and error or random number generation techniques that have been used previously by using a knowledge-based system to ensure the intelligent optimisation within the manufacturing system. A system to optimise manufacturing tolerance allocation to a part known as Knowledge-based Automatic Tolerance Analysis (KATA) has been developed. KATA is a knowledge-based system shell built within AutoCAD. It has the ability for geometry creation in CAD and the capability to optimise the tolerance heuristically as an expert system. Besides the worst-case tolerancing equation to optimise the tolerance allocation, KATA's algorithm is supported by actual production information such as machine capability, types of cutting tools, materials, process capabilities etc. KATA's prototype is currently able to analyse a cylindrical shape workpiece and a simple prismatic part. Analyses of tolerance include dimensional tolerance and geometrical tolerance. KATA is also able to do angular cuts such as tapers and chamfers. The investigation has also led to the significant development of the single tolerance reference technique. This method departs from the common practice of multiple tolerance referencing technique to optimise tolerance allocation. Utilisation of this new technique has eradicated the error of tolerance stackup. The retests have been undertaken, two of which are cylindrical parts meant to test dimensional tolerance and an angular cut. The third is a simple prismatic part to experiment with the geometrical tolerance analysis. The ability to optimise tolerance allocation is based on real production data and not imaginary or random number generation and has improved the accuracy of the expected result after manufacturing. Any failure caused by machining parameters is cautioned at an early stage before an actual production run has commenced. Thus, the manufacturer is assured that the product manufactured will be within the required tolerance limits. Being the central database for all production capability information enables KATA to opt for several approaches and techniques of processing. Hence, giving the user flexibility of selecting the process plan best suited for any required situation.

The thesis investigates the possibility of using simulation for understanding and improving the design of decision making in a real context. The approach is based on the problem of representing decision making behaviour in Discrete Event Simulation. An investigation of existing techniques led to the design of a methodology known as Knowledge Based Improvement (KBI). The KBI covers the key stages of the process of using simulation for understanding and improving the design of decision making. Using a research strategy that involves a case study in Ford, the research tests each stage of KBI. The thesis explains how simulation can be used for understanding real decision making problems and for collecting the data required for modelling individual decision making strategies. The thesis demonstrates the possibility of a simulation based knowledge elicitation in a real context and it investigates the practical difficulties involved in this process. The research tests the process of understanding decision making policies by modelling specific decision makers using Artificial Intelligence. It tests the use of simulation for assessing the decision making strategies and it shows that simulation can be used for identifying efficient strategies and for improving the design of decision making practices. The thesis reports the degree of success of the approach in relation to the data that were collected and it describes the validation checks that were undertaken. In addition, it reports the lessons learned from the application of the KBI methodology, the overall success of the approach and the main limitations that were identified during the implementation.

In this study, we deal with the profit oriented partial disassembly line balancing problem which seeks a feasible assignment of selected disassembly tasks to stations such that the precedence relations among the tasks are satisfied and the profit is maximized. We consider two versions of this problem. In the profit maximization per cycle problem (PC), we maximize the profit for a single disassembly cycle given the task times and costs, part revenues and demands and station costs. We propose a heuristic solution approach for PC based on the liner programming relaxation of our mixed integer programming formulation. In the profit maximization over the planning horizon problem (PH), the planning horizon is divided into time zones each of which may have a different disassembly rate and a different line balance. We also incorporate other issues such as finite supply of discarded product, subassembly and released part inventories availability, and smoothing of the number of stations across the zones. PH is decomposed into a number of successive per cycle problems, which are solved by a similar heuristic approach. Computational analysis is conducted for both problems and results are reported.