The demand for better indoor environment has led to a wide use of heating, ventilating and air conditioning (HVAC) systems. Employing advanced HVAC control strategies is one of the strategies to maintain high quality indoor thermal comfort and indoor air quality (IAQ). This thesis aims to analyse and discuss the potential of using advanced control methods to improve the indoor occupants’ comfort. It focuses on the development of controllers of the major factors of indoor environment quality in buildings including indoor air temperature, indoor humidity and indoor air quality. Studies of the development of control technologies for HVAC systems are reviewed firstly. The problems in existing and future perspectives on HVAC control systems for occupants’ comfort are investigated. As both the current conventional and intelligent controllers have drawbacks that limit their applications, it is necessary to design novel control strategies for the urgent issue of indoor climate improvement. Hence, a concept of designing the controllers for indoor occupants’ comfort is proposed in this thesis. The proposed controllers in this research are designed by combining the conventional and intelligent control technologies. The purpose is to optimize the advantages of both conventional and intelligent control methods and to avoid poor control performance due to their drawbacks. The main control technologies involved in this research are fuzzy logic control (FLC), proportional-integral-derivative (PID) control and neural network (NN). Three controllers are designed by combining these technologies. Firstly, the fuzzy-PID controller is developed for improvement of indoor environment quality including temperature, humidity and indoor air quality. The control algorithm is introduced in detail in Section 3.2. The computer simulation is carried out to verify its control performance and potential of indoor comfort improvement in Section 4.1. Step signal is used as the input reference in simulation and the controller shows fast response speed since the time constant is 0.033s and settling time is 0.092s with sampling interval of 0.001s. The simulating result also proves that the fuzzy-PID controller has good control accuracy and stability since the overshot and steady state error is zero. In addition, the experimental investigation was also carried out to indicate the fuzzy-PID control performance of indoor temperature, humidity and CO2 control as introduced in Chapter 5. The experiments are taken place in an environmental chamber used to simulated the indoor space during a wide period from late fall to early spring. The results of temperature control show that the temperature is controlled to be varying around the set-point and control accuracy is 4.4%. The humidity control shows similar results that the control accuracy is 3.2%. For the IAQ control the maximum indoor concentration is kept lower than 1100ppm which is acceptable and health CO2 level although it is slightly higher than the set-point of 1000ppm. The experimental results show that the proposed fuzzy-PID controller is able to improve indoor environment quality. A radial basis function neural network (RBFNN) PID controller is designed for humidity control and a back propagation neural network (BPNN) PID controller is designed for indoor air quality control. Then, in order to further analyze the potential of using advanced control technologies to improve indoor environment quality, two more controllers are developed in this research. A radial basis function neural network (RBFNN) PID controller is designed for humidity control and a back propagation neural network (BPNN) PID controller is designed for indoor air quality control. Their control algorithms are developed and introduced in Section 3.3 and Section 3.4. Simulating tests were carried out in order to verify their control performances using Matlab in Section 4.2 and Section 4.3. The step signal is used as the input and the sampling interval is 0.001s. For RBFNN-PID controller, the time constant is 0.002s, and there is no overshot and steady state error. For BPNN-PID controller, the time constant is 0.003s, the overshot percentage is 4.2% and the steady state error is zero based on the simulating results. Simulating results show that the RBFNN-PID controller and BPNN-PID controller have fast control speed, good control accuracy and stability. The experimental investigations of the RBFNN-PID controller and BPNN-PID control are not included in this research and will carried out in future work. Based on the simulating and experimental results shown in this thesis, the indoor environment quality improvement can be guaranteed by the proposed controllers.

Actor characterisation using Q methodology and three case study investigations of regional technological innovation systems using novel interaction matrices. This thesis addresses regional aspects of the technological field of hydrogen production from waste. It develops the characterisation of experts involved in the innovation of hydrogen from waste technologies through the use of Q methodology; and a new model (IM-TIS) for the analysis of technological innovation systems. The literature review revealed that the sustainable production of hydrogen from waste processes was not well represented. Truffer et al. (2012) identified a need to further investigate the relationships between functions of innovation and how a technological innovation system may change over time. This was reflected in other innovation and transitions literature. Q methodology revealed three different group identities associated with actors involved in the technological innovation system for hydrogen from waste. These identities are, Hydrogen from Waste Advocates, Cautionary Environmentalists and Hydrogen Technologists. The IM-TIS model developed for this research was applied to three case study regions in the field of hydrogen production from waste in the UK. The model is an adaptation of two existing conceptual models, Rock Engineering Systems (RES) and Functions of Innovation. The thesis identifies and reports on the characteristics of groups of experts involved in hydrogen production from waste and their potential importance. The application of IM-TIS to the three regional case studies of Tees Valley, London and South Wales is presented. A further application of the IM-TIS model using pathway analysis is applied to the case study region of London and results are presented in a worked example. This is the first time a model of this type has been applied to technological innovation system case studies in the UK. It is also the first time a variation of the RES model has been applied in the ways presented in this thesis. The new model provides the opportunity to examine the relationships between functions of innovation and identify what may change within the system over time. It is concluded that the IM-TIS model offers an analysis tool for technological innovation systems that can incorporate the relationships and interactions that occur within the system in a non-linear fashion. Evidence from the research suggests that these interactions have not been adequately addressed in previous studies. A further conclusion is that by addressing the production of hydrogen from waste using these methods, hydrogen technologies are shown to be still in an emergent state.

Gypsum rich soils are of wide occurrence in the Middle East. They cover large areas of Iraq. Gypsum is one of the moderately soluble salts that can have significant effect on the engineering properties of soils. The effect of gypsum content and the stress state on the main hydraulic functions, volume change, shear strength and deformation characteristics of unsaturated silty clayey sand were experimentally examined. Statically compacted specimens of synthetic sand-gypsum mixtures were used. A new stress controllable pressure plate device was developed. The modified device was used to establish simultaneously both the stress-dependent soil-water characteristic curves (SD-SWCCs) and the stress-dependent hydraulic conductivity functions (SD-HCFs) during drying and wetting paths. The test results revealed that the parameters of the drying SWCC such as the water holding capacity, the air-entry suction, the air-entry water content, and the residual suction are clearly increased with increasing gypsum content. Same effect of gypsum was noticed on the wetting SWCC parameters. A clear decrease in saturated water content, desorption rate, absorption rate, and water holding capacity with increasing the applied net normal stress was noticed. Transient outflow methods were used to measure the SD-HCFs. An increase in the SD-HCFs with increasing gypsum content was found. Clear hysteresis effects on k(ψ) and minor hysteresis on k(w) were noticed. It was found that the outflow methods can be applicable between the air-entry suction and residual suction only. Direct shear tests were carried out on saturated and unsaturated specimens. The unsaturated specimens were air-dried and tested under constant water content conditions. Matric suction values were evaluated by incorporating the SD-SWCC test results. The friction angle related to matric suction (b), the effective stress parameter (χ), and the suction stress (s′) were found clearly decrease with increasing gypsum content and with increasing the net normal stress level. However, test results of saturated specimens revealed that the effective shear strength parameters (′, c′) are noticeably increased with increasing gypsum content in the soil mixture.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

This research involves the evaluation of municipal landfill leachates for specific hazardous compounds in an effort to qualitatively determine the potential for groundwater contamination. Leachate samples from five landfills were evaluated for thirteen EPA priority pollutants using gas chromatography. In addition, samples were analyzed for total organic carbon (TOC) and total organic halide (TOX). A solids analysis was performed on refuse excavated from one landfill. This analysis included organic halide determination of interstitial liquids, and a total halide determination for each solid sample. A solids/liquid partition coefficient was calculated from the results. The literature review includes a detailed section outlining the biological degradation of hazardous organic compounds in anaerobic environments similar to conditions found in landfills.

Present day society generates large volumes of waste that present an environmental hazard when disposed of in landfills. As our population grows, so does the volume of waste generated and hence the threat to our environment. One method of reducing harmful emissions in landfills is the mechanical-biological pretreatment of waste prior to landfilling. The purpose of this dissertation is to investigate the degree of stabilization of waste in shallow landfills (simulated by test cells) with particular focus on biogas production and quality. Municipal waste was composted in aerobic, open windrows for periods of eight and sixteen weeks. Five test cells, designed and operated according to the PAF model (Pretreatment, Aeration and Flushing) were constructed at the Bisasar Road landfill site. These cells were used to simulate large scale municipal landfill sites. They were filled with fresh and pretreated waste and were used to monitor the dynamics of prolonged aeration and degradation of waste over a period of six months. The cells were monitored on a weekly basis while being aerated. Two flushing events were conducted at the beginning of the passive aeration. Gas emissions were also monitored by recording the methane, carbon dioxide and oxygen volumes per volume of air in probes strategically placed in each cell. These results were then analysed to assess the effect of mechanical-biological pretreatment of municipal solid waste on the emission quality of sanitary landfills and the appropriateness of prolonging the aeration in shallow landfills, as often used in sub-tropical countries. It was found that the design of the test cells was appropriate for the landfilling and stabilization of waste that was aerobically treated. After six months in the test cells, analysis of the waste from each cell showed that the waste was completely degraded. The PAF model, when applied to shallow landfills, is very effective in stabilising waste and would be appropriate for a sub-tropical climate. Waste that is pretreated, placed in shallow landfills, initially flushed and then aerated over a six month period was fully stabilized. The requirement for such treatment would be relatively small amounts of waste, a wet climate and the availability of open space for shallow landfills. This method, therefore, would be very appropriate in a South African context. The major problem with this method may be the generation of large quantities of leachate which will have to be treated and disposed of in an environmentally safe manner. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2006.

This research was carried out at the Bisasar Road Landfill site, Durban, South Africa, / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.

Recently, there has been increased concern about the potential impact of powerboating on freshwater ecosystems. In the case of Loch Lomond, such concern led to the commencement of a programme of boat counting surveys in 1989. In these surveys, it was found that maximum boat numbers are increasing in Loch Lomond. As a logical progression from these surveys, the present study examined the impact of powerboat chemical pollution on the water quality of Loch Lomond. In the first stage of this study, the scale of powerboat pollution was assessed. This was achieved by constructing a simple mathematical model to estimate the total annual discharge of hydrocarbons (HCs) from powerboat emissions into Loch Lomond. By using boat census data and published information about the emission rates of different types of powerboat engines, the total annual input for Loch Lomond was estimated at 25.50 tonnes in 1989 and this input has greatly increased since then. This indicates that there is real potential for hydrocarbon (HC) pollution of Loch Lomond from powerboat operation. Most of the HC material discharged emanated from speedboats powered by outboard motors. To identify and quantify HC pollutant compounds entering water from outboard engines, Gas Chromatography-Mass Spectrometry (GC-MS) analysis was performed on water subject to a controlled pollution discharge from an outboard motor. Altogether, 47 compounds were detected in this exhaust-polluted water (EPW), with most of these being volatile aromatic HCs, such as benzene and alkylated benzenes. Water samples were also taken from three sites in Loch Lomond on two occasions: once in winter, during negligible boat activity and once in summer, at a time of high powerboat activity. No HCs were detected in winter, but some volatile aromatic HC compounds were clearly detectable in summer. These compounds were the same as those most abundant in EPW and found in similar relative proportions. Further experiments in this study involved the analysis of a large number of water samples. To enable this, it was necessary to develop an appropriate new method for the analysis of powerboat exhaust pollutants, which are mostly aromatic HC. All aromatic HCs fluoresce and the new method involved fluorescence spectroscopy analysis, following sample purification by normal-phase column chromatography. This technique is non-destructive allowing subsequent confirmatory analysis by GC-MS. It was found that the new method was fast, precise, highly sensitive and specific to volatile aromatic HCs. The capability of measuring HCs in a large number of samples allowed previously unfeasible experiments investigating: 1) The geographical distribution of powerboat exhaust HCs in Loch Lomond. 2) The depth profile of powerboat exhaust pollutants in the top 1.5 m of the water column. 3) Recovery of water quality, following peak weekend boat activity in summer. It was found that: 1) Volatile aromatic HCs from powerboat exhaust are detectable over much of Loch Lomond on days of heavy powerboat activity, with concentrations of up to 37 ug.l" occurring. 2) Pollutant HCs are found at depths of at least 1.5 m, and are not confined to the surface microlayer (100 urn), The HC distribution with depth was mostly uniform in the field and this was confirmed in controlled experiments in a tank. 3) Recovery of water quality was difficult to demonstrate in the field, possibly as pollution incidents occur continually during summer. 4) HC concentration declined in controlled experiments, in which water was subjected by a controlled pollution discharge from an outboard motor. The time taken for the HC concentration to reach 50 % of the initial HC loading varied but was approximately 7 - 9 days. The toxicity of EPW was investigated by performing 24 hour LC50 (Lethal Concentration for 50 % of test organisms) tests, using the water flea, Daphnia magna (an international standard test organism). The mean LC50 recorded in this study, expressed as the total concentrations ofHC compounds, was 3.72 mg.l". Previous studies suggest that multiplying the Le50 for D. magna by an application factor of 0.001 gives an approximate safe level of a pollutant. Using data collected in this study, a safe level of exhaust He compounds of 3.72 Jlg.r1 would result. In summer, during times of high powerboat activity, such levels are exceeded at many locations in Loch Lomond. The current study has shown that He pollution from a relatively small number of inefficient powered recreational craft using Loch Lomond poses a potential threat to the maintenance of water quality.

This thesis argues that what it terms fever narratives figure prominently in Charles Dickens’s fiction. Fever was regarded not as a symptom but as a generic disease that had sub-species, such as cholera, smallpox, typhus and typhoid, and that presented itself through devastating epidemics that frightened the public and drove the government to enact public health legislation. The core elements of the fever narrative – such as fever’s cause, pathology, treatment and prevention – were still not clearly understood. This inevitably heightened public anxiety and frustration, particularly given lengthy delays in the bureaucratic processes of Parliament and local governments in dealing with fever’s perennial threat. The politically favoured sanitarian narrative influenced Dickens significantly. Sanitarians believed that water and sewer projects in urban localities and improved sanitary practices would prevent most diseases. However, Dickens was influenced also by an alternative approach that this thesis calls the “medical narrative,” comprising a more holistic vision of public health, reliant on improved treatments, greater medical professionalism, and specialized hospitals, in addition to sanitary reform. Dickens’s 1840s novels reflected both approaches, but he emphasized the medical narrative in portrayals of the fevers of individual characters. In the 1850s, the predominant focus of fever narratives in Dickens’s journals and novels became fever of the social body – fever that figuratively infected English institutions or the country as a whole. Dickens’s fever narratives became progressively darker during these two decades and, with each novel onward from Dombey and Son (1846-48), his representations of fever apocalypses infecting both the rich and the poor became more strident, even to the extent of suggesting that the whole institutional and economic infrastructure of the country would suffer an irrevocable blow. The thesis argues that Dickens presented these minatory scenes of vengeance in response to what he perceived as the blindness of the middle class to the condition of the sick and poor of England. This reached a climax with “Revolutionary fever” in A Tale of Two Cities (1859). The thesis presents a final argument that Dickens’s stories of the early 1860s and Our Mutual Friend (1864-65) provided both a continuation of and a denouement for the two previous decades’ fever narratives, by offering a view of the dust of corpse upon corpse of those who were mowed down by fever, and of a river polluted by this dust. However, he foresees also the possibility of the fundamental regeneration of a more humane physical, social and institutional environment in England.

Incineration can reduce the mass and volume of municipal waste significantly but produces solid waste in the form of bottom ash and air pollution control (APC) residues. Landfill is currently the most commonly used disposal option for these ash residues, however, the impact of hazardous compounds in these wastes on the environment during landfilling is becoming more widely appreciated and cheaper, alternative, management options need to be explored. In this research, the treatment of these municipal solid waste incinerator (MSWI) residues by accelerated carbonation is investigated and compared with naturally aged ashes. Both bottom ash and APC residues were carbonated in an atmosphere composed of gaseous CO2. It was found that the carbonation of calcium oxides/hydroxides resulted in the rapid formation of calcium carbonate and that silicate compounds were hydrated. The reduction of pH from 12-12.5 to 7-9 observed upon carbonation was associated with a reduction in availability of soluble salts and meals. Carbonated ash had a higher buffering capacity to acid attack when compared to the untreated, non-carbonated, ash. The bottom and APC ashes sequestrated between 6% and 13% CO2 (w/w dry weight), respectively upon carbonation; and this may be important where the reduction of greenhouse emissions to the atmosphere is concerned.