This thesis is concerned with investigating and understanding the role and consequence of different modelling options and parameter estimation options for modelling a complex plant. As systems become more complicated and required new technologies and methodologies, more sophisticated maintenance models and control policies are need to solve the maintenance problems. The initial chapter introduces the review of previous work on a single component system and multi-component system. Although in recent years there has been a shift in the maintenance literature from consideration of single items to systems composed of several components, so far only a few papers have tackled the modelling of actual multi-component plant. In the third chapter, delay time concept and analysis technique have been presented. Of particularly importance are parameter estimation methods, namely the objective method and the subjective methods. In the fourth chapter the component PM model and the system PM model for downtimes and costs based upon various PM policies are discussed. The key options within maintenance modelling are to determine regular Minspection periods for the system modelled as a whole, and to determine the periods for the plant as a set of separate component models. An extension to the downtime model is presented for the case when the downtime due to failures within system is not small, and impacts upon the estimate of the number of failures arising over a specified time zone. In the following chapter, we address parameter estimation methods using simulated data, and assess the ability of estimation techniques to capture the true parameter values. Particular attention is paid to the problem arising during the parameter estimating process because of the inadequate recording of PM data and implied correlation between model parameters. Finally, a case study is presented of maintenance modelling of production plant in a local company with view to improving current practice. The model developed is based upon the delay time concept where because of an absence of PM data, using the results of earlier chapters, the process parameters and the delay time distribution were estimated from failure data only using the method of maximum likelihood. The modelling was repeated based upon subjective assessmentosf parameter,a nd considerablec onsistencyw ith the objectively based case obtained. For the plant study, modelling indicated the current PM inspection program was ineffective. A snap-shot approach is then applied to assess other ways of reducing the downtime, and the possibility of improving the PM inspection practice. This leads to readily adapted improvements.

This thesis describes the development of a suite of computer programs designed to evaluate the optimum operating strategy for turbine-generators installed in a proposed tidal power barrage. The computer models are of the single-tide type but have been extended to incorporate detailed models of the turbine performance characteristics and operating constraints. The computer programs have been extensively used for studies of the Severn and Mersey barrage proposals in the UK, for one of the proposed barrage schemes in the Bay of Fundy, Canada and for the now-operating scheme at Annapolis Royal, Canada. One of the most important features of these programs is their ability to simulate, using appropriate characteristics, all the different turbine types suitable for tidal power generation. Results are presented of particular studies showing in each case the conclusions reached.

This thesis investigated Supply Chain Management (SCM), a relatively new area of study in Facilities Management (FM) in the UK, where a research gap was identified by the researcher. This study explored SCM in other industries, relating the benefits derived to FM. It identified that SCM is fundamental to FM, as business performance (which FM supports) is influenced by supply chain performance, creating a link between FM supply chain performance and business performance. Furthermore, competitive advantage and cost savings amongst others were found to be driving forces for SCM in FM, from client and supplier perspectives. This thesis focused on the application of models in SCM in FM. Although a comprehensive examination of available supply chain models was not undertaken, an evaluation of three identified the Integrate to Innovate (i2i) m odel relevant f or application in FM. The action research approach adopted by this thesis enabled the researcher gain a deeper understanding of the applicability of the model, and build on knowledge acquired throughout the period of study. To support this methodology, a philosophical stance between positivism and phenomenology, viewing 'reality as a contextual field of information', was adopted. An explanatory case study approach was employed to undertake a contextual analysis of Gestalten, and understand the real world dynamics of SCM in FM. i2i is a five-level model and three-part framework that evaluates supply chain relationships. Three case studies were undertaken in this thesis, which applied and evaluated the model and framework using a variety of research tools. Each was a learning process for the researcher, adding to the overall outcomes of the research. The thesis identified that the i2i model represented a framework for 'good practice' in SCM in FM. Further development is however required to make it a robust tool, and deliver consistency in its application.

Earthquakes present one of the most devastating hazards on the planet. They threaten the safety of civilians in seismically active regions, and are of extreme concern in applications that demand a high level of safety, i. e. the nuclear industry. However in nearly all cases, the fatalities that occur are as a result of the collapse of man-made structures. Hence the problems facing Civil Engineers who are concerned with seismic mitigation is evident. The dynamic behaviour of their structures must now be accounted for in the design. As our knowledge broadens, structures can, and are being designed to be earthquake resistant. However there are many buildings still standing in seismically active regions which have been designed for static load cases only, or are now of substandard design. Seismic engineering research and application has progressed rapidly over the last few decades, not least in part due to the evolution of computer technology, and our ability to produce computer models which aid us in the design and analysis processes. Hence the research presented focuses on the global behaviour of a typical statically designed tall reinforced concrete building. A literature review has been performed to investigate current mathematical and experimental work which has been carried out with regard to reinforced concrete structures under seismic/cyclic loading. The main point to note from this is that most of the current research has focussed on local behaviour rather than overall global response. The majority of models incorporating global 3D finite element modelling using time history analysis are being created in the Nuclear Industry. After verification work, the ANSYS general purpose finite element computer package has been used to analyse a statically designed 10-storey reinforced concrete building (designed to the rules of BS8110) for static, modal and time-history analyses under a typical (synthetic) earthquake. Certain features have been incorporated in the model with the foresight that these might cause problems under dynamic loading (i. e. softstoreys). The global response of the building has then been investigated, backed up with supporting 'hand' calculations. A 'margins' assessment was carried out mainly on the columns to the requirements of a static code. This enabled the identification of the problematic areas of the building, giving insight into the collapse behaviour and possible areas where design upgrade, attention to workmanship or retrofit may be required. In this process the potential for redistribution and overload capacity of the structure is also demonstrated. In conclusion, a number of suggestions for future work using global response models are made, and the benefits of using the global model approach adopted are discussed in detail. The global response, as opposed to local effects are captured providing insight into the potential for partial or total collapse.

Mith their unique transparent and conductive properties, TCO (transparent conductive oxide) coatings are becoming increasingly studied These commercially important coatings have a promising future due to their various applications as components in optoelectronic devices, photovoltaic solar cells, flat panel displays, electroluminescent devices, etc. Their high transmittance and low resistivity are generally achieved through the use of specific dopant materials, whilst adjustments are made to the deposition processes to improve the structure of the coatings. TCO coatings are commonly deposited by the magnetron sputtering process. Sputtering normally takes place from a solid plate, known as the target, of the material to be deposited. Clearly, each solid target can only be of a single composition. Thus, to change the compositions ofthe coatings, the whole target has to be replaced Furthermore, alloy, or doped targets can be very expensive and the choice ofavailable compositions is likely to be limited. In this project, instead of using solid targets, metal or ceramic powder blends were used as the targets. The powder blends were spread across the surface of a magnetron and lightly tamped down to produce a smooth surface. The benefits of this approach are that any material that is available in powderform can be considered as a target material and alloy or multi-component compositions can be readily blended The basic aim of this project, therefore, was to produce novel TCO coatings by magnetron sputteringfrom powder targets. The coatings were deposited in a specially designed rig with a number of important features, including a pulsed DC power supply and a closed magnetic field. The project concentrated on the production of commercially useful zinc oxide-based TCO coatings. Coatings were produced with different dopant materials and concentrations, and their optical and electrical properties were measured. After the coatings were annealed at 500 *Cfor 2 hours in vacuo, aluminum and gallium doped zinc oxide coatings showed their low resistivity, which were no larger than 5.19xI0-3S2cm, and the lowest resistivity was obtained from 3at% A 1-doped ZnO coating; 1.95 xI 00cm. The average transmittance in the visible range of the ZnO coatings was 90%. From this, optimal compositions were identified For comparison purposes, coatings were also produced of the TCO material most commonly used at present; namely ITO (Indium tin oxide). The results showed that ITO coatings generally had lower resistivity and visible transmittance, (4-6xlO-492cm and 80-8216), than doped ZnO coatings. Also, the electrical and optical properties of ITO coatings were very sensitive to the content of oxygen in the deposition atmosphere. Finally, theflexibility offered by this approach was exploited through the use of multi-component target compositions to produce TCO coatings with tailored optical and electrical properties.

Human localisation of sound in enclosed spaces is a cross-disciplinary research topic, with important applications in auditory science, room acoustics, spatial audio and telecommunications. By combining an accelerated model of $3$D sound propagation in rooms with a perceptual model of spatial processing, this thesis provides an integrated framework for studying sound localisation in enclosed spaces on the horizontal plane, with particular emphasis on room acoustics applications. The room model is based on the finite difference time domain (FDTD) method, which has been extended to include physically-constrained sources and binaural receivers based on laser-scanned listener geometries. The underlying algorithms have been optimised to run on parallel graphics hardware, thus allowing for a high spatial resolution, and accordingly, a significant decrease of numerical dispersion evident in the FDTD method. The perceptual stage of the model features a signal processing chain emulating the physiology of the auditory periphery, binaural cue selection based on interaural coherence, and a final decision maker based on supervised learning. The entire model is shown to be capable of imitating human sound localisation in different listening situations, including free field conditions and at the presence of sound occlusion, diffraction and reflection. Results are validated against subjective data found in the literature, and the model's applications to the fields of room acoustics and spatial audio are demonstrated and discussed.

The theoretical part of the thesis is divided into four chapters dealing with the problems of radon and its influence on the human organism. The first chapter summarizes the basic issues of human environment, interaction and division of the environment based on its function (use for life). The second chapter focuses on the radioactivity of environment, specifically on ionizing radiation, its formation and division, as well as its effect on human health. The next chapter is about radon, its formation, sources of radon, its distribution in the environment, measurements, protection against radon, the history of problems with radon and the Radon Programme of the Czech Republic. The last chapter of the theoretical part is dedicated to lung carcinoma, its origin, distribution, diagnosis, treatment and relationship with the incidence of radon based on surveys of selected epidemiological studies. The practical part of the thesis includes description of source data and methodology of processing data sets of radon equilibrium equivalent concentration (EEC), number of deaths by causes and population status. Chapter of results includes map outputs of radon EEC, mortality rates of carcinoma lung for men, women, and both sexes. Other parts of the outputs are the results of the correlation analysis of the...

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Indoor spaces have become increasingly prevalent in human lives. While scholarship in other fields has studied the relationship between humans and the indoors, it has not been readily investigated in Geography. This study draws from prior research in Building Design, Managerial Science, and Education to examine the relationship between building users and resources in indoor spaces. To better understand how users seek resources in an indoor, academic space, this research asks: (1) what spaces and resources do building users value?; and (2) how are their perceptions of value associated with observed measures of occupancy? This research takes place in Goodwin Hall, on the Blacksburg campus of Virginia Polytechnic Institute and State University. This research relies on surveys conducted in 2018 as well accelerometer data collected in 2018 to examine the relationship between users' perception and use of resources in informal learning environments. Through quantitative analysis this research tests the ideal free distribution hypothesis. Findings indicate that certain measures of use and value support the ideal free distribution hypothesis. These results help to lay a groundwork for future geographic research in indoor spaces. / Master of Science / Indoor spaces have become increasingly created, used, and occupied by humans. Geography, as a discipline, has traditionally studied the relationship that humans have with their surrounding outdoor environments. This research studies how humans interact with their indoor environments. Other disciplines, such as Building Design, Managerial Science, and Education have examined how indoor spaces can impact human movement, behavior, and choice. Geography is a spatial discipline (observes how variables affect each other over space) and offers a differing lens to view human-indoor relationships. To better understand how users seek resources in an indoor, academic space, this research asks: (1) what spaces and resources do building users value?; and (2) how are their perceptions of value associated with observed measures of occupancy? This research takes place in Goodwin Hall, on the Blacksburg campus of Virginia Polytechnic Institute and State University. This research relies on surveys conducted in 2018 as well accelerometer data, which observes the amount of acceleration, collected in 2018 to examine the relationship between how users' view and use resources and spaces within an indoor environment. Through quantitative analysis this research tests the ideal free distribution hypothesis. Findings show that certain measures of use and value support the ideal free distribution hypothesis. Findings from this paper help to provide more insight into how humans interact with indoor spaces and lays the groundwork for future indoor geographic research.

Master of Arts / Department of Geography / John A. Harrington Jr / The Rainwater Basin Wetland Complex of south-central Nebraska is a region of great climatic variability, as well as tremendous ecological importance. The Rainwater Basin Wetland Complex is located at the focal point of the Central North American migratory bird flyway, and supports in excess of twelve million birds during the spring migration period. The physical landscape has been significantly altered from its pre-settlement state by agricultural conversion via the draining of over ninety percent of the native wetlands. Due to the region’s highly variable continental climate, interannual wetland water levels are also highly variable and currently unpredictable. I have used multi-year analysis, including the construction of a regional water budget assessment, to study which climatic variables play the most crucial role in the late-winter filling of wetlands. Research objectives were met by analyzing ten cold season (Oct – Feb) climatic variables and an annual measure of wetland area for five years, in order to better understand possible climatic drivers of wetland hydrologic functioning levels in March. Longer time series of winter season climatic information were also assessed to help place the recent and more detailed analysis into a longer climatic context. Research results will aid local management agencies in the future through enhanced knowledge of how climatic variation impacts wetland function. Seasonal precipitation and temperature was favored by the linear regression analysis, while the multiple regression analysis placed higher emphasis on February evapotranspiration rates, February snow depth, and February snowfall. Lastly, the hydrologic water budget that was created for the study area had several highly correlated output variables with basin-wide flooded hectares, particularly annual snow storage.