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The electron density of an ion is strongly influenced by its environment in a condensed phase. When the environment changes, for example due to thermal motion, non-trivial changes in the electron density, and hence the interionic interactions occur. These interactions give rise to many-body effects in the potential. In order to represent this phenomenon in molecular dynamics (MD) simulations a method has been developed in which the environmentally-induced changes in the ionic properties are represented by extra dynamical variables. These extra variables are handled in an extended Lagrangian formalism by techniques analogous to those used in Car and Parrinello's ab initio MD method. At its simplest level (the polarizable-ion model or PIM) induced dipoles are represented. With the PIM it has proven possible to quantitatively account for numerous properties of divalent metal halides, which had previously been attributed to unspecific "covalent" effects. In the solid-state the prevalence of layered crystal structures is explained. Analogous non-coulombic features in liquid structures, in particular network formation in "strong" liquids like ZnCl₂ , have been studied as has network disruption by "modifiers" like RbCl. This work leads to an understanding of the relationship between the microscopic structure and anomalous peaks ("prepeaks") seen in diffraction data of such materials. The PIM was extended to include induced quadrupoles and their effect studied in simulations of AgCl. In the solid-state it is found that the both are crucial in improving the phonon dispersion curves with respect to experiment. In the liquidstate polarization effects lower the melting point markedly. For oxides the short-range energy has been further partitioned into overlap and rearrangement energies and electronic structure calculations are used to parameterize a model in which the radius of the anion is included as an additional degree of freedom. The Bl → B2 phase transition is studied in MgO and CaO and the differences between the new model and a rigid-ion model are analysed.

The purpose of the study was to develop a pilot simulation package for use by secondary school administrators. Included in the package were video tapes of critical incidents about beginning secondary teachers, background information about the setting for the incidents, problem solving forms, and the reaction of a panel of experts to the critical incidents. The procedures used in the study included the following: conducting a survey in search of critical incidents, selecting nine critical incidents to be video taped, writing scripts, video taping the nine critical incidents, selecting a panel of experts to provide model responses to. each of the critical incidents, testing the simulation package of materials in a secondary school administration class at Ball State Unim versity, evaluating the use of the simulation package, presenting and analyzing the data collected, presenting the findings and conclusions, and presenting the supplementary simulation materials used in the study. The data collected in the study were analyzed in the following categories: the reality of the role of the principal, the perception of the problem of new teacher orientation, the effect of the simulation on the participants' preparation to help new teachers, the transfer of learning to the real environment, the motivational value of the complete simulation experience, the general impression regarding this simulation experience, the degree of help provided by various experiences during simulation, the motivational value of the video tapes, the priority of new teacher orientation, the interest and value of the video taped incidents, the value of simulation as a teaching technique, time for consideration of the incidents, the degree of adequacy of the background information, the degree of adequacy of the introductory information, suggestions for improvement, and additional suggestions for the use of the simulation package. The conclusions of the study were as follows: 1. Participant perception of the overall problem of new teacher orientation was enhanced through participation in the simulation experience. 2. The group interaction experiences were considered the most valuable experiences during simulation. 3. Concern for new teacher orientation and supervision may be increased through the use of simulation. 4. New teacher orientation was considered a high priority item in the preparation of educational administrators. 5. The video taped incidents that ranked the highest in interest to the participants presented relatively difficult problems to solve, and the incidents that ranked the lowest in interest to the participants presented problems that were elementary. 6. The educational administrators supported the use of simulation as an instructional method, and they requested more information about the role of the principal and the teachers involved. 7. Video tapes, which were inexpensively developed and tested, were considered a worthwhile part of the simulation by the participants. The recommendations for further study were as follows: 1. This simulation package should be used with other administrators in workshops or in other learning situations in order to validate or reject the findings of this study. 2. This study should be followed up to determine whether or not there has been any transfer in learning to actual administrative performance on-the-job. 3. The possibility of adapting the simulation materials or approach of this study for use with college students prior to and during their student teaching experience should be considered.

Following the sharp rise in oil prices in late 1973 and early 1974, most oil exporting countries adopted highly expansionary fiscal and monetary policies aimed at rapid development of their economies. In Nigeria the role of the public sector since then has been significantly increased as most of the oil revenue accrues directly to the Federal government rather than to individuals. Given the host of economic problems faced by the country in the 1970s the debate over the role of the public sector in a mixed capitalist economy in the process of economic growth gains more relevance. / The essence of this study is to analyze the consequence of alternative patterns of government policy on economic growth in Nigeria. The study provides a general framework that is useful in studying the effects of alternative government policies on the domestic economy and also in analyzing alternative patterns of allocating the sudden increase in domestic resources. Using policy simulation experiments, an alternative policy package is suggested and the relative effectiveness of various policy instruments used by the government are examined.

The performance of two innovative collector-loop heat exchangers used in pumped circulation solar water heaters was investigated experimentally and numerically, and TRNSYS simulation models were developed for evaluating long-term performance. The heat exchangers evaluated are a narrow gap mantle on a vertical tank and a falling film system in a standard gas hot water tank. The falling film system is based on minor changes to a mass produced tank and does not require the addition of a special purpose heat exchanger. The heat exchangers were assessed for a range of operating conditions to quantify the overall heat exchanger UAhx value and the effect of thermal stratification in the tank. Flow visualisation experiments and CFD modelling were also performed to provide detailed understanding of the operation characteristics of the heat exchangers. For each heat exchanger, the measured and computed collector loop side heat transfer coefficients were correlated by developing new Nusselt number versus Reynolds and Prandtl number functions. New heat transfer correlations were developed for both types of heat exchanger and have been implemented into full solar water heater simulation models in TRNSYS. Predictions of tank stratification conditions in each heat exchanger were in good agreement with experimental data. Compared to a standard direct circulation system, the annual performance of the mantle system and falling film system are 8% and 18% less respectively. The decrease in system performance is due to the heat exchanger penalty and reduced thermal stratification in the storage tank, however they have the added features of freeze protection and suitability for hard water areas. They are also cheaper to manufacture than convectional heat exchange systems. The annual performance of a falling film solar water heater was shown to be affected by de-stratification if an in-tank electric booster was used. However, improved performance can be achieved if an advanced switching controller is used to modulate the flow rate such that the collector return temperature is always higher than the temperature in the top of the tank.

Copies of author's previously published articles inserted. / Amendments sheet pasted onto back end-paper. / Bibliography: p. 231-245. / xii, 247 p. : col. ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Develops a model predicting fertilisation success rates in natural populations of scallops with focus on Chlamys bifrons and Chlamys asperrima. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1999

iv, 215 leaves ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Computing Science, 1974

The aim of this thesis is to develop a method of optical modelling that can be used to predict visual performance of the eye. It is intended to give visual acuity estimates under normal circumstances and under a wide range of optical treatments such as photorefractive keratectomy (PRK) to correct refractive error. Visual performance refers to the performance of the eye under various conditions such as decreased object contrast, defocus and change in pupil size. (For complete abstract open document)

This thesis addresses the scheduling and control of shop-floor production units that operate in a highly autonomous and distributed environment. The distinct feature of this environment is the heterarchical nature of the control where the scheduling function is quite independently carried out by the units. The units solve only part of the overall problem while resolving conflicts to maintain consistent global schedules. The need for communication and coordination, in such circumstances, introduces many complexities that affects the quality of the schedules produced. These include lapses of open-loop control due to uncertainty of up-to-date status information, asynchronous behaviour, and uncontrollable propagation of conflicts. / A behaviour-based approach is introduced to solve these problems. Using this approach, the organisation of the shop-floor is viewed as similar to a colony of ants or an eco-system. The units operate quite independently but continue to adapt their schedules to changes in their environment. While they may not directly negotiate to resolve conflicts, their cooperation is innate or in-built through their local adaptive actions. This individual cooperative action of the units brings about a collective behaviour that produces the desired emergent global schedules. The major focus of this research is in examining the link between the individual and collective behaviours and developing a model that realises the desired scheduling functionality at the shop level. / In order to achieve high scheduling performance (both locally and globally) a model of a unit incorporating dynamic problem decomposition, allocation algorithms and adaptation mechanisms is developed. For the latter, a reinforcement learning model is used to adapt the scheduling horizon. In fact, an important contribution if this research is the novel view we take of the problem and the manner of adaptation. In addition, a communication model for simulating the scheduling behaviours is designed using concepts of Holonic and other emerging concepts of manufacturing systems. / The model is tested for a number of scheduling problems representing a variety of production situations. Preliminary results indicate an impressive scheduling performance comparable to well-known heuristics. Further examination indicates the types of dynamic behaviour that can be expected of such a model, including the levels of unresolved conflicts, the adaptability in the face of uncertainty, consequence of alternative communication policies and the sensitivities to adaptation. / This thesis has also a strong qualitative theme in reviewing and consolidating the concepts underlying the design and operational attributes of autonomous distributed organisations of the shop-floor.

Drying is a common process in a number of industries. Products such as furs, wools, textiles, clay, timber, grains, fruits, and vegetables, at some stage, require drying. Review of the literature reveals that commercial dryers are highly inefficient due to various factors. One such factor is that commercial dryers are generally not equipped with heat recovery facilities. Heat pumps can provide a very efficient means of recovering both sensible and latent heat, hence energy loss can be substantially reduced. Furthermore, a heat pump always delivers more heat than the work input to the compressor. These two salient features render heat pump drying a premium alternative for efficient use and conservation of energy in drying industries.