2 resultados para State Crack-Growth
em Glasgow Theses Service
Resumo:
This research aimed to explore the privileging of growth and its influence on planning in England. The research examined two contrasting case studies: Middlesbrough Borough Council and Cambridge City Council. The analysis of growth privileging is rooted within a constructionist ontology which argues that planning is about the way in which people construct value relative to the function of land. This perspective enables the research to position growth privileging as a social construction; a particular mental frame for understanding and analyzing place based challenges and an approach which has been increasingly absorbed by the UK planning community. Through interviews with a range of planning actors, the first part of the research examined the state of planning in the current political and economic context and the influence that a privileging of growth has on planning. The second part of the research investigated the merits and feasibility of the capabilities approach as an alternative mental frame for planning, an approach developed through the work of Amartya Sen and Martha Nussbaum. The research results disaggregate the concept of economic growth, based on the responses of interviewees and conclude that it is characterized by homogeneity. Growth is valued, not only because of its economic role, for example, supporting jobs and income but its potential in creating diversity, enriching culture and precipitating transformative change. Pursuing growth as an objective has a range of influences upon planning. In particular, it supports a utilitarian framework for decision-making which values spatial decisions on their ability to support aggregate economic growth. The research demonstrates the feasibility and merits of the capabilities approach as a means with which to better understand the relationship between planning and human flourishing. Based on this analysis, the research proposes that the capabilities approach can provide an alternative ‘mental frame’ for planning which privileges human flourishing as the primary objective or ‘final end’ instead of economic growth.
Resumo:
Hydrogen is considered as an appealing alternative to fossil fuels in the pursuit of sustainable, secure and prosperous growth in the UK and abroad. However there exists a persisting bottleneck in the effective storage of hydrogen for mobile applications in order to facilitate a wide implementation of hydrogen fuel cells in the fossil fuel dependent transportation industry. To address this issue, new means of solid state chemical hydrogen storage are proposed in this thesis. This involves the coupling of LiH with three different organic amines: melamine, urea and dicyandiamide. In principle, thermodynamically favourable hydrogen release from these systems proceeds via the deprotonation of the protic N-H moieties by the hydridic metal hydride. Simultaneously hydrogen kinetics is expected to be enhanced over heavier hydrides by incorporating lithium ions in the proposed binary hydrogen storage systems. Whilst the concept has been successfully demonstrated by the results obtained in this work, it was observed that optimising the ball milling conditions is central in promoting hydrogen desorption in the proposed systems. The theoretical amount of 6.97 wt% by dry mass of hydrogen was released when heating a ball milled mixture of LiH and melamine (6:1 stoichiometry) to 320 °C. It was observed that ball milling introduces a disruption in the intermolecular hydrogen bonding network that exists in pristine melamine. This effect extends to a molecular level electron redistribution observed as a function of shifting IR bands. It was postulated that stable phases form during the first stages of dehydrogenation which contain the triazine skeleton. Dehydrogenation of this system yields a solid product Li2NCN, which has been rehydrogenated back to melamine via hydrolysis under weak acidic conditions. On the other hand, the LiH and urea system (4:1 stoichiometry) desorbed approximately 5.8 wt% of hydrogen, from the theoretical capacity of 8.78 wt% (dry mass), by 270 °C accompanied by undesirable ammonia and trace amount of water release. The thermal dehydrogenation proceeds via the formation of Li(HN(CO)NH2) at 104.5 °C; which then decomposes to LiOCN and unidentified phases containing C-N moieties by 230 °C. The final products are Li2NCN and Li2O (270 °C) with LiCN and Li2CO3 also detected under certain conditions. It was observed that ball milling can effectively supress ammonia formation. Furthermore results obtained from energetic ball milling experiments have indicated that the barrier to full dehydrogenation between LiH and urea is principally kinetic. Finally the dehydrogenation reaction between LiH and dicyandiamide system (4:1 stoichiometry) occurs through two distinct pathways dependent on the ball milling conditions. When ball milled at 450 RPM for 1 h, dehydrogenation proceeds alongside dicyandiamide condensation by 400 °C whilst at a slower milling speed of 400 RPM for 6h, decomposition occurs via a rapid gas desorption (H2 and NH3) at 85 °C accompanied by sample foaming. The reactant dicyandiamide can be generated by hydrolysis using the product Li2NCN.