The design of a high pressure solvent extraction process using liquid ammonia as solvent

The literature on the potential use of liquid ammonia as a solvent for the extraction of aromatic hydrocarbons from mixtures with paraffins, and the application of reflux, has been reviewed. Reference is made to extractors suited to this application. A pilot scale extraction plant was designed comprising a Scm. diameter by 12Scm. high, 50 stage Rotating Disc Contactor with 2 external settlers. Provision was made for operation with, or without, reflux at a pressure of 10 bar and ambient temperature. The solvent recovery unit consisted of an evaporator, compressor and condenser in a refrigeration cycle. Two systems were selected for study, Cumene-n-Heptane-Ammonia and Toluene-Methylcyclohexane-Ammonia. Equlibrium data for the first system was determined experimentally in a specially-designed, equilibrium bomb. A technique was developed to withdraw samples under pressure for analysis by chromatography and titration. The extraction plant was commissioned with a kerosine-water system; detailed operating procedures were developed based on a Hazard and Operability Study. Experimental runs were carried out with both ternary ammonia systems. With the system Toluene-Methylcyclohexane-Ammonia the extraction plant and the solvent recovery facility, operated satisfactorily, and safely,in accordance with the operating procedures. Experimental data gave reasonable agreement with theory. Recommendations are made for further work with plant.

British lesbian, gay and bisexual psychologies:theory, research and practice

Gain insight into crucial British mental health approaches for LGB individuals. There is very little collaborative literature between LGB-affirmative psychologists and psychotherapists in the United States and the United Kingdom. British Lesbian, Gay, and Bisexual Psychologies: Theory, Research, and Practice may well be a crucial beginning step in building dialogue between these two countries on important LGB psychotherapy developments. Leading authorities comprehensively examine the latest studies and effective therapies for LGB individuals in the United Kingdom. Practitioners will discover an extensive survey of the most current developments to supplement their own work, while educators and students will find diverse expert perspectives on which to consider and broaden their own viewpoints. This unique book offers an informative introduction to British psychosocial perspectives on theory, research, and practice. British Lesbian, Gay, and Bisexual Psychologies provides a critical exploration of the recent history of LGB psychology and psychotherapy in the United Kingdom, focusing on key publications and outlining the current terrain. Other chapters are organized into two thematic sections. The first section explores theoretical frameworks in United Kingdom therapeutic practice, while the second section examines sexual minority identities and their needs for support and community. Topics in British Lesbian, Gay, and Bisexual Psychologies include: - similarities and differences between LGBT psychology and psychotherapy in the United States and United Kingdom - gay affirmative therapy (GAT) as a positive framework - existential-phenomenological approach to psychotherapy - core issues in the anxiety about whether or not to “come out” - object relations theory - exploring homo-negativity in the therapeutic process - aspects of psychotherapy that lesbians and gay men find helpful - research into how the mainstreaming of lesbian and gay culture has affected the lives of LGB individuals - study into LGB youth issues - difficulties of gay men with learning disabilities—with suggestions on how to offer the best psychological service - a study on gay athletes’ experiences of coming out in a heterosexist world British Lesbian, Gay, and Bisexual Psychologies takes a needed step toward sharing valuable psychosocial perspectives between countries. This useful, enlightening text is perfect for educators, students, psychologists, psychotherapists, and counselors working in the field of sexuality.

Neural Network Modelling with Input Uncertainty: Theory and Application

It is generally assumed when using Bayesian inference methods for neural networks that the input data contains no noise. For real-world (errors in variable) problems this is clearly an unsafe assumption. This paper presents a Bayesian neural network framework which accounts for input noise provided that a model of the noise process exists. In the limit where the noise process is small and symmetric it is shown, using the Laplace approximation, that this method adds an extra term to the usual Bayesian error bar which depends on the variance of the input noise process. Further, by treating the true (noiseless) input as a hidden variable, and sampling this jointly with the network’s weights, using a Markov chain Monte Carlo method, it is demonstrated that it is possible to infer the regression over the noiseless input. This leads to the possibility of training an accurate model of a system using less accurate, or more uncertain, data. This is demonstrated on both the, synthetic, noisy sine wave problem and a real problem of inferring the forward model for a satellite radar backscatter system used to predict sea surface wind vectors.

The transformational implementation of JSD process specifications via finite automata representation

Conventional structured methods of software engineering are often based on the use of functional decomposition coupled with the Waterfall development process model. This approach is argued to be inadequate for coping with the evolutionary nature of large software systems. Alternative development paradigms, including the operational paradigm and the transformational paradigm, have been proposed to address the inadequacies of this conventional view of software developement, and these are reviewed. JSD is presented as an example of an operational approach to software engineering, and is contrasted with other well documented examples. The thesis shows how aspects of JSD can be characterised with reference to formal language theory and automata theory. In particular, it is noted that Jackson structure diagrams are equivalent to regular expressions and can be thought of as specifying corresponding finite automata. The thesis discusses the automatic transformation of structure diagrams into finite automata using an algorithm adapted from compiler theory, and then extends the technique to deal with areas of JSD which are not strictly formalisable in terms of regular languages. In particular, an elegant and novel method for dealing with so called recognition (or parsing) difficulties is described,. Various applications of the extended technique are described. They include a new method of automatically implementing the dismemberment transformation; an efficient way of implementing inversion in languages lacking a goto-statement; and a new in-the-large implementation strategy.

Collaborative alliances and organisational innovation : a study of the innovation process

Despite the voluminous studies written about organisational innovation over the last 30-40 years our understanding of this phenomenon continues to be inconsistent and inconclusive (Wolfe, 1994). An assessment of the theoretical and methodological issues influencing the explanatory utility of many studies has led scholars (e.g. Slappendel, 1996) to re-evaluate the assumptions used to ground studies. Building on these criticisms the current study contributes to the development of an interactive perspective of organisational innovation. This work contributes empirically and theoretically to an improved understanding of the innovation process and the interaction between the realm of action and the mediating effects of pre-existing contingencies i.e. social control, economic exchange and the communicability of knowledge (Scarbrough, 1996). Building on recent advances in institutional theory (see Barley, 1986; 1990; Barley and Tolbert, 1997) and critical theory (Morrow, 1994, Sayer, 1992) the study aims to demonstrate, via longitudinal intensive research, the process through which ideas are translated into reality. This is significant because, despite a growing recognition of the implicit link between the strategic conduct of actors and the institutional realm in organisational analysis, there are few examples that theorise and empirically test these connections. By assessing an under researched example of technology transfer; the government's Teaching Company Scheme (TCS) this project provides a critique of the innovation process that contributes to theory and our appreciation of change in the UK government's premier technology transfer scheme (QR, 1996). Critical moments during the translation of ideas illustrate how elements that are linked to social control, economic exchange and communicability mediate the innovation process. Using analytical categories i.e. contradiction, slippage and dysfunctionality these are assessed in relation to the actions (coping strategies) of programme members over a two-year period. Drawing on Giddens' (1995) notion of the duality of structure this study explores the nature of the relationship between the task environment and institutional environment demonstrating how and why knowledge is both an enabler and barrier to organisational innovation.

The process of strategic change:a management perspective

This thesis is concerned with the management processes concerned with complex strategic decision in organisations. The research has sought to explore these processes by taking as its focus the reconstruction of decision processes a) on the basis of an historical study of an industry and in particular a major company in that industry; and b) the perception and understanding of strategic decision processes and change by managers involved in companies in that industry. The main body of analysis and theoretical contributions arise from the detailed analysis of extended depth interviews with managers carried out in 1980 and 1983 which trace thirteen years of the strategic development of a firm. In so doing, extensive use is made of verbatim accounts by managers of events and their interpretation of events. This is then compared with data gathered from.similar interviews with managers of two other companies and examined in the light of existing research and theory in the field. The thesis both provides a detailed insight into the processes associated with the identification and resolution of complex strategic issues and also generates a body of theory concerning the mechanisms by which strategic decisions and the processes of strategic change are interwoven with the cultural and political fabric of organisations. The thesis is divided into four parts. The first part deals with the background to the research, provid1ng a fuller summary of the purpose, structure and content of the thesis and a discussion of relevant previous research and the methodology employed herein. The second part mainly provides case studies of the industry and the main company studied. The third part is a detailed presentation and analysis of data. The fourth part is a synthesis of the findings and consolidation of the theoretical interpretation advanced in the thesis.

In search of a theory of list memory: an inquiry into the efects of long-term information on short-term recall

Over recent years, evidence has been accumulating in favour of the importance of long-term information as a variable which can affect the success of short-term recall. Lexicality, word frequency, imagery and meaning have all been shown to augment short term recall performance. Two competing theories as to the causes of this long-term memory influence are outlined and tested in this thesis. The first approach is the order-encoding account, which ascribes the effect to the usage of resources at encoding, hypothesising that word lists which require less effort to process will benefit from increased levels of order encoding, in turn enhancing recall success. The alternative view, trace redintegration theory, suggests that order is automatically encoded phonologically, and that long-term information can only influence the interpretation of the resultant memory trace. The free recall experiments reported here attempted to determine the importance of order encoding as a facilitatory framework and to determine the locus of the effects of long-term information in free recall. Experiments 1 and 2 examined the effects of word frequency and semantic categorisation over a filled delay, and experiments 3 and 4 did the same for immediate recall. Free recall was improved by both long-term factors tested. Order information was not used over a short filled delay, but was evident in immediate recall. Furthermore, it was found that both long-term factors increased the amount of order information retained. Experiment 5 induced an order encoding effect over a filled delay, leaving a picture of short-term processes which are closely associated with long-term processes, and which fit conceptions of short-term memory being part of language processes rather better than either the encoding or the retrieval-based models. Experiments 6 and 7 aimed to determine to what extent phonological processes were responsible for the pattern of results observed. Articulatory suppression affected the encoding of order information where speech rate had no direct influence, suggesting that it is ease of lexical access which is the most important factor in the influence of long-term memory on immediate recall tasks. The evidence presented in this thesis does not offer complete support for either the retrieval-based account or the order encoding account of long-term influence. Instead, the evidence sits best with models that are based upon language-processing. The path urged for future research is to find ways in which this diffuse model can be better specified, and which can take account of the versatility of the human brain.

An analysis of the effect of process parameters on the formability of sheet metal

This investigation is in two parts, theory and experimental verification. (1) Theoretical Study In this study it is, for obvious reasons, necessary to analyse the concept of formability first. For the purpose of the present investigation it is sufficient to define the four aspects of formability as follows: (a) the formability of the material at a critical section, (b) the formability of the material in general, (c) process efficiency, (d) proportional increase in surface area. A method of quantitative assessment is proposed for each of the four aspects of formability. The theoretical study also includes the distinction between coaxial and non-coaxial strains which occur, respectively, in axisymmetrical and unsymmetrical forming processes and the inadequacy of the circular grid system for the assessment of formability is explained in the light of this distinction. (2) Experimental Study As one of the bases of the experimental work, the determination of the end point of a forming process, which sets the limit to the formability of the work material, is discussed. The effects of three process parameters on draw-in are shown graphically. Then the delay of fracture in sheet metal forming resulting from draw-in is analysed in kinematical terms, namely, through the radial displacements, the radial and the circumferential strains, and the projected thickness of the workpiece. Through the equilibrium equation of the membrane stresses, the effect on the shape of the unsupported region of the workpiece, and hence the position of the critical section is explained. Then, the effect of draw-in on the four aspects of formability is discussed throughout this investigation. The triangular coordinate system is used to present and analyse the triaxial strains involved. This coordinate system has the advantage of showing all the three principal strains in a material simultaneously, as well as representing clearly the many types of strains involved in sheet metal work.

Predicting and diagnosing faults in wastewater treatment process by Bayesian Belief Networks

Diagnosing faults in wastewater treatment, like diagnosis of most problems, requires bi-directional plausible reasoning. This means that both predictive (from causes to symptoms) and diagnostic (from symptoms to causes) inferences have to be made, depending on the evidence available, in reasoning for the final diagnosis. The use of computer technology for the purpose of diagnosing faults in the wastewater process has been explored, and a rule-based expert system was initiated. It was found that such an approach has serious limitations in its ability to reason bi-directionally, which makes it unsuitable for diagnosing tasks under the conditions of uncertainty. The probabilistic approach known as Bayesian Belief Networks (BBNS) was then critically reviewed, and was found to be well-suited for diagnosis under uncertainty. The theory and application of BBNs are outlined. A full-scale BBN for the diagnosis of faults in a wastewater treatment plant based on the activated sludge system has been developed in this research. Results from the BBN show good agreement with the predictions of wastewater experts. It can be concluded that the BBNs are far superior to rule-based systems based on certainty factors in their ability to diagnose faults and predict systems in complex operating systems having inherently uncertain behaviour.

The mathematical modelling of the environmental performance of buildings as an aid in the design process

This thesis is a theoretical study of the accuracy and usability of models that attempt to represent the environmental control system of buildings in order to improve environmental design. These models have evolved from crude representations of a building and its environment through to an accurate representation of the dynamic characteristics of the environmental stimuli on buildings. Each generation of models has had its own particular influence on built form. This thesis analyses the theory, structure and data of such models in terms of their accuracy of simulation and therefore their validity in influencing built form. The models are also analysed in terms of their compatability with the design process and hence their ability to aid designers. The conclusions are that such models are unlikely to improve environmental performance since: a the models can only be applied to a limited number of building types, b they can only be applied to a restricted number of the characteristics of a design, c they can only be employed after many major environmental decisions have been made, d the data used in models is inadequate and unrepresentative, e models do not account for occupant interaction in environmental control. It is argued that further improvements in the accuracy of simulation of environmental control will not significantly improve environmental design. This is based on the premise that strategic environmental decisions are made at the conceptual stages of design whereas models influence the detailed stages of design. It is hypothesised that if models are to improve environmental design it must be through the analysis of building typologies which provides a method of feedback between models and the conceptual stages of design. Field studies are presented to describe a method by which typologies can be analysed and a theoretical framework is described which provides a basis for further research into the implications of the morphology of buildings on environmental design.

By writers for writers: developing a writer-centred model of the writing process

This thesis, set within an Action Research framework, details the development and validation of a writer-centred model of the writing process. The model was synthesised within the boundaries of a writers’ group for MA students. The initial data collected, and analysed using the principles of grounded theory, were retrospective descriptions of group members’ writing processes. After initial analysis, additional data, from group members’ writing, and from audio recordings, were used for further analysis, and to form a model of the writing process. To ascertain whether the model had value outside the specific context in which it was made, it was validated from three different perspectives. Firstly, the retrospective descriptions of other writers were collected and analysed, using the model as a framework. Secondly, the model was presented at academic conferences; comments about the model, made by members of the audience, were collected and analysed. Finally, the model was used in writing courses for PhD students. Comments from these students, along with questionnaire responses, were collected and the content analysed. Upon examination of all data sources, the model was updated to reflect additional insights arising from the analysis. Analysis of the data also indicated that the model is useable outside its original context. Potential uses for the model are 1) raising awareness of the process of writing, 2) putting writers at ease, 3) serving as a starting point for individuals or groups to design their own models of the writing process, and 4) as a tool to help writers take control of their writing processes.

The role of line managers in employee career management:an attachment theory perspective

Line managers increasingly play a key role in organizational career development systems, yet few studies have examined the nature of this role or its implications for employee career attitudes and behaviors. In two studies, we used attachment theory to explore this issue. In Study 1, in-depth interviews (N = 20) showed that employees viewed career management as a relational process in which line managers are expected to act as ‘caregiver’ to support individualized career development. Study 2 was a large-scale international survey (N = 891). Participants scoring higher on attachment avoidance in their line manager relationships reported more negative perceptions of career growth opportunities, lower participation in organizational career development activities and higher turnover intentions. Trust in the organization partially mediated the relationship. Theoretical and practical implications for HRM are discussed.

Shaping strategy as a structuration process

Research on top managers’ strategizing behavior has addressed how they shape either the structural context or the interpretations of organization members. I offer a structuration theory framework integrating these two partial explanations and treating strategy shaping as socially dynamic. A qualitative seven-year analysis of top managers in three universities shows a sequential pattern of shaping strategy first in the action and then in the institutional realm, and also a simultaneous pattern of shaping strategy in both realms at once. Both patterns are successful in weakly institutionalized strategy contexts, whereas the simultaneous pattern is more successful in strongly institutionalized strategy contexts.

Toward a theory of coordinating:creating coordinating mechanisms in practice

This paper uses a practice perspective to study coordinating as dynamic activities that are continuously created and modified in order to enact organizational relationships and activities. It is based on the case of Servico, an organization undergoing a major restructuring of its value chain in response to a change in government regulation. In our case, the actors iterate between the abstract concept of a coordinating mechanism referred to as end-to-end management and its performance in practice. They do this via five performative–ostensive cycles: (1) enacting disruption, (2) orienting to absence, (3) creating elements, (4) forming new patterns, and (5) stabilizing new patterns. These cycles and the relationships between them constitute a process model of coordinating. This model highlights the importance of absence in the coordinating process and demonstrates how experiencing absence shapes subsequent coordinating activity.