No description available.

No description available.

The advent of microprocessors has created the possibility of developing low cost adaptive controllers for small process plants which in the past badly needed but could not afford such controllers. To examine the practicality of developing advanced low cost microprocessor based controller, this thesis describes the development of a non-linear adaptive controller for a nylon crimping plant which is a typical example of small process plants. In order to test the algorithm on site, an algorithm development/implement device basing on a novel multi-tasking concept was developed. This novel microprocessor based device can perform program development, on-line algorithm test and data logging at the same time, while, still maintaining its small size for easy transportation. When the control algorithm was fully developed and tested, a low cost dedicated controller using an Intel 8085 processor was designed to house the algorithm and as a direct replacement of the original analogue controller.

No description available.

No description available.

Patterns of communication in the decision-making process of Design Team Architects are considered. Variations in the verbal content of Architect and other Design Team member interaction behaviour are analysed over the various stages of the design process. A pilot study building design and a main subject study building design are investigatted on a longditudinal basis. Fourteen other building designs are investigated on a cross sectional basis. The presented results represent a data collection period of approximately eighteen months. Design Team interaction is measured using content analysis. The measurement scales used are largely based upon existing methodologies, although some measurement scales are developed specifically for this research. Quantitative data analysis is by mainframe computer, using analysis programs which are developed specifically for this research. Additional qualitative substantiations are provided by extracts of supportive interview responses. The results show pronounced patterns of variation in the interaction content of Design Team members throughout the design process over a range of design types. The conclusions are of use to Design Team members since they illustrate the likely patterns of future interaction for the future stages of any design process. Potential areas of interaction conflict are presented, together with likely variations in Design Team member preoccupations as the design develops. Reference to the results allow the Designer to design in order to avoid likely design interaction problems associated with long term variations in Design Team interaction behaviour. Results indicate that the Architect becomes less assertive during the middle stages of the design, as does the influence of the initial brief. The Architect is consistently the most creative Design Team member, although cost considerations increasingly influence the decision-making process of the Architect, largely at the expense of aesthetic considerations. The professional Design Team members increasingly form a coalition against the Client Representative, to some extent as a defence against late stage disruptive cost reduction exercises, as construction factors increasingly influence interaction behaviour.

No description available.

No description available.

This thesis concerns the development of rigorous global optimisation techniques and their application to process engineering problems. Many Process Engineering optimisation problems are nonlinear. Local optimisation approaches may not provide global solutions to these problems if they are nonconvex. The global optimisation approach utilised in this work is based on interval branch and bound algorithms. The interval global optimisation approach is extended to take advantage of information about the structure of the problem and facilitate efficient solution of constrained NLPs using interval analysis. This is achieved by reformulating the interval lower bounding procedure as a convex programming problem which allows inclusion of convex constraints in the lower bounding problem. The approach is applied to a number of standard constrained test problems indicating that this algorithm retains the wide applicability of the interval methods while allowing efficient solution of constrained problems. A new approach to the construction of modular flowsheets is developed. This approach allows construction of flowsheets from linked unit models which enable the application of a number of global optimisation algorithms. The modular flowsheets are constructed with 'generic' unit operations which provide interval bounds, linear bounds, derivatives and derivative bounds using extended numerical types. The genericity means that new 'extended types' can be devised and used without rewriting the unit operations models. The new interval global optimisation algorithm is applied to the generic modular flowsheet. Using interval analysis and automatic differentiation as the arithmetic types, lower bounding linear programs are constructed and used in a branch and bound framework to globally optimise the modular flowsheet.

Process systems engineering has provided with a range of powerful tools to chemical engineers for synthesis, optimisation and control using thorough understanding of the processes enhanced with the aid of sophisticated and accurate multi-faceted mathematical models. Crystallization processes have rarely benefited from these new techniques, for they lack in models that could be used to bridge the gaps in their perception before utilising the resulting insight for the three above mentioned tasks. In the present work, first a consistent and sufficiently complex models for unit operations including MSMPR crystallizer, hydrocyclone and fines dissolver are developed to enhance the understanding of systems comprising these units. This insight is then utilised for devising innovative techniques to synthesise, optimise and control such processes. A constructive targeting approach is developed for innovative synthesis of stage-wise crystallization processes. The resulting solution surpasses the performance obtained from conventional design procedure not only because optimal temperature profiles are used along the crystallizers but also the distribution of feed and product removal is optimally determined through non-linear programming. The revised Machine Learning methodology presented here for continual process improvement by analysing process data and representing the findings as zone of best average performance, has directly utilised the models to generate the data in the absence of real plant data. The methodology which is demonstrated through KNO₃ crystallization process flowsheet quickly identifies three opportunities each representing an increase of 12% on nominal operation. An optimal multi-variable controller has been designed for a one litre continuous recycle crystallizer to indirectly control total number and average size of crystals from secondary process measurements. The system identification is solely based on experimental findings. Linear Quadratic Gaussian method based design procedure is developed to design the controller which not only shows excellent set-point tracking capabilities but also effectively rejects disturbance in the simulated closed loop runs.