Today the majority of UK's energy needs are met by fossil fuels. An energy sector that uses 30% of this energy and generates 28% of the total emissions is domestic sector. To reduce the emissions generated by fossil fuels UK government decided to increase the energy coming from renewable sources by 2020. A renewable energy that can contribute is solar energy. Solar thermal collectors and photovoltaics are two means of transforming solar energy to thermal and electrical energy. The limited space in the roofs and the cost of the technologies will prevent families to use both systems together in their roof A hybrid energy system combine the use of two or more alternative power sources will help to increase the system's total efficiency. The photovoltaic/thermal (PV/T) system is a hybrid structure that converts part of the sun's radiation to electricity and part to thermal energy. This research work focuses on the production of new approaches on hybrid PV/T systems. PV/T systems using water and air have been introduced and a literature review conducted in order to identify positives and negatives of these systems. Experiments also conducted by using water and air as heat transfer medium, and the results helped to work as a benchmark performance to the new approaches. These technologies were heat pipes, phase change materials and micro encapsulated phase change materials. The technologies exist for years but their use in the specific application is new. A literature review was undertaken to provide an understanding of these technologies and identified findings that have contributed to the design of the systems. Experimental work was carried out incorporating these technologies in the rear of a PV and the results indicated comparable performance with PV/T-water and PV/Tair. Five performance indicators were employed to help with the comparison of the systems. These were electrical and thermal efficiency, the total energy efficiency, the primary energy saving efficiency and the exergy efficiency. From these five indicators the primary energy saving efficiency that shows how much fossil fuel is saved and the exergy efficiency that could give the optimum working conditions of each system was the most valuable ratings. For the PV/PCM model a new simulation program was developed to help validate the experimental work. Also an environmental and economic study was undertaken to compare if the new systems could help reduce the C02 emissions and if they were feasible to become commercial products. Finally the conclusions gained have been presented and recommendations fo r future work have been made.

This serves to introduce the present research and is chiefly historical. It deals briefly with methods of assessing the coking ability of coals and also with early modern, and contemporary investigations upon coke formation. The author's earlier work on the distillation of oil from coals is described fully since it forms both the starting point and the basis of the present research. This work showed the power of retention of oil which is capable of 'wetting' the surface of the coal, up to temperatures of 420 degrees C., was an essential characteristic of coking coals. Part II deals with attempts to add more oil mechanically to improve the coking performance of various coals.

A low cost Cook-Off experimental facility has been established to provide a convenient method of ranking explosives in their response to Cook-Off by the time to event under two widely different heating rates and at two different scales. This thesis describes the literature review undertaken as preparation for the purposed study and all the experimental work developed comprising the design of the trials vehicles, the demonstration of their suitability for Fast and Slow Cook-Off trials with confined explosive systems, the preparation of the samples and test vehicles to be trialled as well as the set-up of adequate facilities to undertake the scheduled firing programme. Results are reported for Cook-Off tests on TNT, RDX, and their mixtures. The emphasis of the study is on time to event, and temperature at event, and in addition a qualitative assessment of the violence of the event was made by examination of the fragments of the vehicles, although it is accepted that the relatively light and low cost design of the vehicle may lead to variable confinement in the early stages of the explosive event, and hence to a wider spread of responses than would be obtained from a more heavily confined and more costly vehicle. The test vehicles give results, which differentiate between the various explosives and explosive mixtures trialled and between the scales. More experiments are required to establish the reproducibility of the measurements. The design of the equipment makes this a relatively inexpensive undertaking. The experiment was modelled using published kinetic data, but the calculated time to event differed from that observed to different extents at the two scales. It is hypothesised that the mechanism may change over the prolonged heat soaks and that quantitative scaling is not possible with the available information. Further work is also suggested using a different type of Cook-Off test vehicle, which will in our opinion reduce even further the cost of Cook-Off testing, due to reduction in man-hours of preparation involved and manufacture cost of the Cook-Off test vehicles, and consequently of ranking of explosives.

No description available.

Instrumental accounts of policy start at the policy document—the framework for action— and move on from there, identifying gaps, criticising shortcomings or praising proposals. Critical and interpretive reviews of policymaking regard it as a process to be examined rather than an outcome to be managed. At the core of this thesis, the Biofuels Industrial Strategy of South Africa presents a new terrain in which to examine the policy process before such instrumental approaches become pertinent. In doing so, pervasive underlying 'win-win' and 'pro-poor' narratives and associated discourses articulated and legitimised by constituent vested interests, global and local networks (the biofuels assemblage) and the power relations between them are scrutinised as part of the 'messy politics' of policymaking. Through such an investigation, the thesis adds to the understanding of policymaking in South Africa and seeks to instil the importance of interpretive approaches to analysing policymaking. Ultimately, decisions around biofuels highlight the importance of meaning and cognitive frameworks that policymakers bring to the table and the symbolic nature of policy. It must, for example be made clear what purpose policy actually fulfils rather than simply subscribing to social constructions of instrumental success or failure. There is a lingering if not hegemonic supposition that although South Africa has 'good' policy, implementation 'fails' due to capacity. While this may be the case, it is inadequate as an explanation of 'policy failure', where remedial action then becomes more about improving capacity, which may only serve to reify the abstract disjuncture between policy and practice. Rather an attempt should be made to 'problematise' what makes policy either 'good' or 'bad' but more so unpack the taken for granted in policymaking and how policy itself is part of wider sense making processes whilst also fulfilling symbolic roles beyond the merely instrumental. Given an inescapable reality in which politics and knowledge share a dialectic relationship in policymaking, we should rethink the veracity and technocratic assumptions of evidence-based policymaking and the value of 'knowledge' in policymaking processes over and above the way policymakers frame and interpret issues themselves. Considering 'evidence' to be a deus ex machina or panacea, as it is in New Public Management proposals, may very well be short sighted. Neglecting the interpretive and political aspects of policymaking, especially within the technical realms of renewable energy in general and biofuels in particular is equally myopic. Deconstructing the nature of the policymaking process around biofuels has wider implications or findings for the South African context. One can see, for example, the perseverance but slight reconfiguration of the Minerals-Energy Complex (MEC) and a largescale technological fetish that continues to control the vision and direction of renewable energy transitions (and policies thereof) in the country. Corporate networks are, however, only part of the picture and decisions and decision makers involved in the process extend beyond an 'MEC elite', but increasingly include ANC political gatekeepers who inscribe their own ideologies and meanings into policy. These are especially acute in the form of narratives surrounding decisions made, such as the broad-brush exclusion of maize in the face of an emotive and racially politicised food-versus-fuel storyline.

The optimisations of reduction and operation of Ni-YSZ anode supported micro tubular cells on pure methane were studied. A major problem of SOFCs is nickel anode performance on methane and higher hydrocarbons. The aim of this work was to study the effect of reduction and operation of anode-supported microtubular SOFCs using methane as both reductant and fuel. The results were compared to those from optimised operation using hydrogen. To measure mechanical strength, the three point bending test was employed. Temperature programmed oxidation (TPO) results were investigated to measure the carbon deposition on the anode in order to assess potential damage to the cermet catalyst. Also field emission scanning electron microscope (FE-SEM) and Energy-Dispersive X-ray spectroscopy EDS results were analysed on the anode surface.

In the world today there is a massive dependency on fossil fuels as they are currently used to provide around 80% of the world’s energy. This is hugely detrimental to the environment and is a major contributory factor in climate change. Biofuel is a renewable energy source that is already being used to lessen some of the fossil fuel dependency. 2nd generation biofuels, by using non-food parts of plants, circumvent the food vs fuel argument, and by using farming waste or surplus can also avoid changing land use problems. Additionally liquid biofuels can use existing infrastructure for storage and delivery, and also fit into current lifestyles. Cost-effective 2nd generation biofuel production is directly affected by the presence of the polymer lignin in plant biomass, as it has been shown to impede enzymatic sugar release (saccharification) that is used for biofuel production. The work undertaken in this project developed a high-throughput methodology for the assessment of straw lignin content and composition across a large population of elite varieties in the economically important cereal crop, barley. Saccharification yield was also measured across the same population along with a number of other agronomically important traits, such as thousand-grain weight, biomass, mechanical stem properties and height. The data provided by these measurements allowed correlations between traits to be identified and their strength gauged. Genome wide association studies (GWAS) were also carried out and identified influential regions of the genome for each trait. The results revealed varying levels of association between measured traits and lignin content and monomeric constituents. Importantly a negative connection was shown between lignin content and saccharification yield, with lignin content being responsible for approximately 1/5th of the variation seen. Interestingly there was no correlation between lignin content and mechanical stem properties, an important factor in the agronomically important trait, lodging. GWAS results revealed a number of genomic regions that were influential across several traits indicating regions that would be difficult to separate through breeding due to their close proximities. However, unique QTL were identified for saccharification yield and lignin content providing candidates for breeding or genetic manipulation to improve the crop for biofuel production.

The main objective of this thesis is to develop relatively simple but reasonable engineering models within a CFD software framework to simulate fire in a compartment and fire growth and propagation in enclosures in which solid combustibles are involved through wall or ceiling linings. Gas phase combustion, radiation and solid fuel combustion are addressed in this study. At the heart of this study is the integration of the three sub-models representing the key elements mentioned above in compartment fire development and other auxiliary calculations such as the evaluation of the radiative properties of gas-soot mixture, temperature calculation for non-burning solid surfaces, etc. into a complete fire spread model. Shortcomings in the conventional six-flux radiation model are highlighted. These were demonstrated through a simple artificial test case and corrected in the modified six-flux model. The computational cost and accuracy of the six-flux model and the discrete transfer method (DTM) using different number of rays are also investigated. A simple empirical soot model is developed based on experimental observations that soot formation occurs in the fuel rich side of the chemical reaction region and the highest soot concentration is found in the same region. The soot model is important to evaluate the radiative properties of the gas-soot mixture in fires. By incorporating the gas-phase combustion model, the radiation models and the soot model, substantial improvement in the predicted upper layer temperature profiles is achieved in the simulations of one of the Steckler's room fire test. It is found that radiation plays an important, perhaps dominant role in creating the nearly uniform temperature distribution in the upper layer. The integral method to calculate temperatures of non-combustible solids is extended to be capable of dealing with the non-linearity of the reradiation at the solid surface(top surface) exposed to a fire and the convective heat loss at the opposite surface. The integral method is economic and simple for the calculation of temperatures of non-combustible solids. Pyrolysis models for nonchaning and charring solid combustibles are developed. The mass loss rates produced by the noncharring model for PMMA are in excellent agreement with experimental data. The charring model produced predictions for the mass loss rates and temperature distribution of a wood sample in very close agreement to that measured. Finally, qualitative and quantitative verifications for the integrated fire spread model are carried out. The model is demonstrated to be capable of both qualitatively and quantitatively predicting fire, fire growth and development within compartment fire scenarios.

The threats of global warming attributed to fossil fuel combustion, combined with increasing energy demands and a growing population, have generated interests in diversifying the world energy mix. Biofuels from microalgae offer a sustainable renewable option and do not suffer the sustainability issues associated with early forms of bioenergy. However, research efforts of nearly 5 decades have not resulted in any significant gains and have motivated further investigation into novel techniques. The dilute nature of microalgae suspensions often requires dewatering and drying, which adds to energy intensity and costs associated with recovery processes. Curiously, the conventional recovery techniques do not consider the characteristic tendency of microalgae cells for surface attachment. This behaviour of cells, coupled with the discovery of a non-porous adsorbent material, NyexTM particles, has brought to the fore an exciting prospect. This has motivated the underpinning question behind this research; does the non-porous characteristic of the NyexTM particles presents an opportunity to recover microalgae cells from suspension using an adsorption technique?Using Chlamydomonas reinhardtii as a model microalgae strain, preliminary batch studies revealed a rapid recovery of the cells onto the NyexTM particles; nearly 90% recovery was attained within one minute, which depends on suspension concentration. At a correlation coefficient, R2 = 0.99, the Freundlich isotherm was found to give a better description of batch systems than the Langmuir isotherm, which suggests that cell coverage onto the NyexTM particles may not be a simple monolayer adsorption. Although a low adsorptive capacity of 0.55 mg/g was measured, the equilibrium parameter (1⁄) of about 0.6 was well within the range for favourable adsorption (i.e. 0 - 1). Further studies undertaken suggest that the recovery of cells could be driven by a hydrophobic-hydrophobic interaction, electrostatic forces of attraction and the flocculating behaviour of the NyexTM particles. Fixed bed studies showed that the lack of pores led to an early breakthrough. However, findings demonstrated that unlike most column studies, the bed capacity was a more valuable parameter to assess the column performance. Unexpectedly, depressed breakthrough curves, where bed exhaustion never attained Ct/C0 = 1.0, were observed. Nonetheless, the modified dose response (MDR) model was found to predict the experimental bed capacity to a greater degree of accuracy than other models. Furthermore, this research exploited the logistic features of the Bohart-Adams and the Clark models to adapt them to the experimental data. The adapted models significantly improved the accuracy of predictions with R2 values > 0.99 for the depressed breakthrough curves. The conductive nature of NyexTM particles was explored to electrochemically regenerate the adsorbent and reuse it to recover more cells. A current density of 32 mA.cm-2 was sufficient to inactivate the cells, regenerate the adsorbent and attain a maximum percentage recovery. Interestingly, scanning electron micrograph showed that the membranes of the adsorbed cells were ruptured, during NyexTM regeneration, potentially leading to lipid release. The maximum lipids extracted into a hexane solvent was estimated as 30 μg/mL at a current density of 64 mA.cm-2.Overall, the potential to recover microalgae cells onto a non-porous adsorbent has been demonstrated. The prospect of rupturing membranes of adsorbed cells offers the opportunity to use this technique to recover microalgae cells for potential biofuel applications. The results obtained from this research can serve as the impetus to further exploit this novel procedure. Future work should consider high lipid producing varieties of microalgae strains, develop a robust protocol to account for all forms of lipids released and undertake an energy and cost analysis to develop the technology further.

In the past fifty years, a need to address the ethical and social dimensions in the biosciences has become pervasive. To this end, notions of bioethics, and an associated range of methodologies have been institutionalised throughout the UK biosciences; talk of research ethics, public engagement, various forms of technology assessment, and recently notions of responsible innovation in technoscientific worlds is increasingly commonplace. A desire to unpack discourse and action surrounding these practices sits at the heart of this thesis. Of particular interest are the ways that different groups construct the ethical dimensions of biofuel development and deployment and then distribute responsibility for addressing them. To achieve this, I find analytic power by deploying theory from the interpretative social sciences, namely the sociology of bioethics and science and technology studies. Empirically, I use controversy about the development and deployment of biofuels as a means to analyse, primarily through documentary analysis and qualitative interview, how three prominent groups (non-governmental organisations, public research funders and scientists) construct understandings of ethics and then distribute responsibility for addressing those issues. This approach makes it possible to see that the constitution of ethical issues (their ‘form’) and the ways that they are addressed (the ‘task’ of ethics) are both tightly coupled to the situations from which they arise. They are thus fundamentally multiple, locally contingent and often unpredictable. Using a range of discursive strategies and actions, actors are able to negotiate, blurring in and out of focus, what counts as an appropriate issue of concern, who should be addressing it and how. Dominant traditions of theory and practice have a tendency to standardise the form and task of ethics, such as in terms of issue types (e.g. ‘Playing God’) and the methods for addressing them (e.g. public engagement). I argue that ethical dimensions’ situated nature should be acknowledged rather than ignored and is fundamental to making research more ‘socially robust’. However, this tension between dominant institutionalised forms and lived experiences is not easily resolved because it forces an engagement with the roles of those who are tasked with steering knowledge production. Hope is, however, offered by new approaches that have explicitly sought to deal with such tensions in new forms of knowledge production and new models of collaboration.