34,299 research outputs found

    Turbina de corriente libre para bombeo de agua

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    El abastecimiento de agua para usos productivos y dom√©sticos es uno de los problemas m√°s graves en las zonas rurales de nuestro pa√≠s. Estas necesidades energ√©ticas pueden ser satisfechas gracias al empleo de energ√≠a renovable. El tema analizado en la presente tesis es la descripci√≥n y an√°lisis de una turbina que aprovecha la energ√≠a cin√©tica de un r√≠o. Este dispositivo se denomina turbina de corriente libre, y se presenta como una alternativa para la provisi√≥n de agua en zonas en los que no existe un salto disponible. Como se sabe, la energ√≠a cin√©tica de un r√≠o es m√°s "densa" (m√°s energ√≠a por unidad de √°rea) que la energ√≠a e√≥lica pero no puede competir con la energ√≠a disponible en un peque√Īo salto. En este trabajo se describen los diferentes tipos de turbinas de corriente libre que han sido experimentados en varios lugares del mundo, y se selecciona un tipo que luego viene presentado en detalle. Para el an√°lisis del comportamiento de la turbina en el agua se han utilizado las relaciones que gobiernan el comportamiento de los √°labes en un medio fluido, haciendo uso extensivo de las relaciones que se emplean para el dimensionamiento de aerobombas, puesto que este tipo de dispositivos son conceptualmente similares a las turbinas de corriente libre. Entre las m√°s importantes conclusiones a las que llega este estudio, es que una de las caracter√≠sticas ge√≥metricas indispensables e importantes en el dimensionamiento del rotor es el √°ngulo de setting, el cual determina el modo en que cada parte del rotor contribuye a la generaci√≥n de potencia. Se ha encontrado adem√°s que para tener la facilidad de manufacturar el √°labe con cuerda constante, es necesario mantener un √°ngulo de curvatura a lo largo del mismo, lo que permite aprovechar al m√°ximo la energ√≠a de la corriente. Para lograr la m√°xima potencia de un sistema como el propuesto se debe tratar que el proceso de fabricaci√≥n del sistema d√© dimensiones lo m√°s cercanas posibles a las dimensiones determinadas te√≥ricamente, y que esto sea posible de obtener a un costo razonable.Trabajo de investigaci√≥

    The development of the Kent coalfield 1896-1946

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    One of the unique features of the Kent Coalfield is that it is entirely concealed by newer rocks. The existence of a coalfield under southern England, being a direct link between those of South Wales, Somerset and Bristol in the west and the Ruhr, Belgium. and northern France in the east, was predicted by the geologist R. A. C. Godwin-Austen as early as 1856. It was, however, only the rapid increase in demand for Britain's coal in the last quarter of the nineteenth century that made it worth considering testing this hypothesis. The first boring was made in the years 1886-90, and although it discovered coal, this did not in itself prove the existence of a viable coalfield. This could be done only by incurring the heavy cost of boring systematically over a wide area. As the financial returns from such an undertaking were uncertain, it was not surprising that in the early years, around the turn of the century, a dominant role was played by speculators, who were able to induce numerous small investors to risk some of their savings in the expectation of high profits. As minerals in Britain were privately owned, the early pioneer companies not only had to meet the cost of the exploratory borines, but also, if they were not to see the benefit of their work accrue to others, lease beforehand the right to mine coal from local landowners in as much of the surrounding area as possible. This policy was pursued most vigorously by Arthur Burr, a Surrey land specula tor, who raised capital by creating the Kent Coal Conoessions Ltd. and then floating a series of companies allied to it. Burr's enterprise would probably have been. successful had it not been for the water problems encountered at depth in -v- the coalfield. As a result, the Concessions group found itself in control of most of the coalfield, but without the necessary capital to sink and adequately equip its 01ffi collieries. By 1910, however, the discovery of iron ore deposits in east Kent, coupled with the fact that Kent coal was excellent for coking purposes, began to attract the large steel firms of Bolckow, Vaughan Ltd. and Dorman, Long & Co. Ltd. in to the area. The First World War intervened, however, to delay their plans, and to provide an extended lease of life to the Concessions group, which, by the summer of 1914, was facing financial collapse. By the time Dorman, Lone & Co, in alliance with Weetman Pearson (Lord Cowdray), had acquired control over the greater part of the coalfield from the Concessions group, not only was the country's coal industry declining, but so was its steel industry, which suffered an even more severe rate of contraction during the inter-war years. As a result, Pearson and Dorman Long Ltd. was forced to concentrate just on coal production, and this in turn was hampered not only by the water problems, but also by labour shortages and the schemes introduced by the government in 1930 to restrict the country's coal output, in an attempt to maintain prices and revenue in the industry. Nevertheless, production did show a substantial increase between 1927 and 1935, after which it declined as miners left the coalfield to return to their former districts, where employment opportunities were improving in the late thirties. Supporting roles were played in the inter-war years by Richard Tilden Smith, a share underwriter turned industrialist with long standing interests in the coalfield, who acquired one of the Concessions group's two collieries, and by the Powell Duffryn Steam Coal Co. Ltd., which through subsidiary companies, took over the only colliery to be developed by a pioneer company outside the Concessions group. The impossibility of Kent coal, because of its nature, ever gaining more than token access to the more lucrative household market, and then the failure of the local steel industry to materialise meant that the -vi- companies had to develop alternative outlets for their growing outputs. Although nearness to industrial markets in the south-east of England did confer certain advantages were poor consolation for the hoped for developments of either the early pioneers or the later industrialists. Instead of the expected profits, the companies mostly incurred losses, and only the company acquired by Powell Duffryn ever paid a dividend to its shareholders in the years before nationalisation. From the point of view of the Kent miners, the shortage of labour in the coalfield, particularly in the years 1914-20 and 1927-35, was to an important extent responsible for their being amongst the highest paid in the industry. At the same time the more favourable employment opportunities prevailing in Kent compared with other mining districts enabled the Kent Nine Workers Association to develop into a well organised union, which on the whole was able to look after the interests of its members fairly successfully. Throughout the period 1896 to 1946 the Kent Coalfield existed very much at the margin of the British coal industry. Its failure to develop substantially along the lines envisaged by either the early pioneers or by the later industrialists meant that its importance in national terms always remained small

    Consent and the Construction of the Volunteer: Institutional Settings of Experimental Research on Human Beings in Britain during the Cold War

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    This study challenges the primacy of consent in the history of human experimentation and argues that privileging the cultural frameworks adds nuance to our understanding of the construction of the volunteer in the period 1945 to 1970. Historians and bio-ethicists have argued that medical ethics codes have marked out the parameters of using people as subjects in medical scientific research and that the consent of the subjects was fundamental to their status as volunteers. However, the temporality of the creation of medical ethics codes means that they need to be understood within their historical context. That medical ethics codes arose from a specific historical context rather than a concerted and conscious determination to safeguard the well-being of subjects needs to be acknowledged. The British context of human experimentation is under-researched and there has been even less focus on the cultural frameworks within which experiments took place. This study demonstrates, through a close analysis of the Medical Research Council's Common Cold Research Unit (CCRU) and the government's military research facility, the Chemical Defence Experimental Establishment, Porton Down (Porton), that the `volunteer' in human experiments was a subjective entity whose identity was specific to the institution which recruited and made use of the subject. By examining representations of volunteers in the British press, the rhetoric of the government's collectivist agenda becomes evident and this fed into the institutional construction of the volunteer at the CCRU. In contrast, discussions between Porton scientists, staff members, and government officials demonstrate that the use of military personnel in secret chemical warfare experiments was far more complex. Conflicting interests of the military, the government and the scientific imperative affected how the military volunteer was perceived

    Elite perceptions of the Victorian and Edwardian past in inter-war England

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    It is often argued by historians that members of the cultivated Elite after 1918 rejected the pre-war past. or at least subjected it to severe denigration. This thesis sets out to challenge such a view. Above all, it argues that inter-war critics of the Victorian and Edwardian past were unable to reject it even if that was what they felt inclined to do. This was because they were tied to those periods by the affective links of memory, family, and the continually unfolding consequences of the past in the present. Even the severest critics of the pre-war world, such as Lytton Strachey, were less frequently dismissive of history than ambivalent towards it. This ambivalence, it is argued, helped to keep the past alive and often to humanise it. The thesis also explores more positive estimation of Victorian and Edwardian history between the wars. It examines nostalgia for the past, as well as instances of continuity of practice and attitude. It explores the way in which inter-war society drew upon aspects of Victorian and Edwardian history both as illuminating parallels to contemporary affairs and to understand directly why the present was shaped as it was. Again, this testifies to the enduring power of the past after 1918. There are three parts to this thesis. Part One outlines the cultural context in which writers contemplated the Victorian and Edwardian past. Part Two explores some of the ways in which history was written about and used by inter-war society. Part Three examines the ways in which biographical depictions of eminent Victorians after 1918 encouraged emotional negotiation with the pas

    Victims' Access to Justice in Trinidad and Tobago: An exploratory study of experiences and challenges of accessing criminal justice in a post-colonial society

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    This thesis investigates victims' access to justice in Trinidad and Tobago, using their own narratives. It seeks to capture how their experiences affected their identities as victims and citizens, alongside their perceptions of legitimacy regarding the criminal justice system. While there have been some reforms in the administration of criminal justice in Trinidad and Tobago, such reforms have not focused on victims' accessibility to the justice system. Using grounded theory methodology, qualitative data was collected through 31 in-depth interviews with victims and victim advocates. The analysis found that victims experienced interpersonal, structural, and systemic barriers at varying levels throughout the criminal justice system, which manifested as institutionalized secondary victimization, silencing and inequality. This thesis argues that such experiences not only served to appropriate conflict but demonstrates that access is often given in a very narrow sense. Furthermore, it shows a failure to encompass access to justice as appropriated conflicts are left to stagnate in the system as there is often very little resolution. Adopting a postcolonial lens to analyse victims' experiences, the analysis identified othering practices that served to institutionalize the vulnerability and powerlessness associated with victim identities. Here, it is argued that these othering practices also affected the rights consciousness of victims, delegitimating their identities as citizens. Moreover, as a result of their experiences, victims had mixed perceptions of the justice system. It is argued that while the system is a legitimate authority victims' endorsement of the system is questionable, therefore victims' experiences suggest that there is a reinforcement of the system's legal hegemony. The findings suggest that within the legal system of Trinidad and Tobago, legacies of colonialism shape the postcolonial present as the psychology and inequalities of the past are present in the interactions and processes of justice. These findings are relevant for policymakers in Trinidad and Tobago and other regions. From this study it is recognized that, to improve access to justice for victims, there needs to be a move towards victim empowerment that promotes resilience and enhances social capital. Going forward it is noted that there is a need for further research

    Dise√Īo de un sistema de drenaje pluvial urbano en la ciudad de Otuzco, La Libertad mediante el uso del modelo matem√°tico SWMM

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    Los efectos de las lluvias se ven agravadas por la impermeabilizaci√≥n de los suelos, el fen√≥meno de El Ni√Īo y el cambio clim√°tico, ocasionando serios da√Īos en los sectores social, econ√≥mico, educativo y de salud del pa√≠s. Por consiguiente, es importante proyectar un eficiente sistema de drenaje pluvial urbano que proteja el medio ambiente, trate de reutilizar el agua y evite perjuicios en las edificaciones para una mejor calidad de vida en el poblador. El proyecto se realiza en la localidad de Otuzco, regi√≥n de La Libertad, zona que no cuenta con una adecuada evacuaci√≥n de agua de lluvia exponi√©ndola a los problemas mencionados. Por otro lado, la normativa nacional establece que el drenaje pluvial es un servicio b√°sico y exige su obligatoriedad en toda habilitaci√≥n urbana. Por lo tanto, es necesario y justificable el desarrollo de este trabajo. El objetivo de la presente tesis es dise√Īar un sistema de drenaje pluvial urbano con la ayuda del modelo matem√°tico SWMM en la ciudad de Otuzco en La Libertad. El SWMM (en ingl√©s Storm Water Management Model, en espa√Īol Modelo de Gesti√≥n de Aguas Pluviales) es un software que permite conocer el comportamiento del agua y hacer c√°lculos m√°s precisos, optimizando de esta forma tiempo y costo. Siguiendo una metodolog√≠a se realiza un an√°lisis hidrol√≥gico para hallar las precipitaciones de dise√Īo y obtener los par√°metros de la cuenca permitiendo definir las caracter√≠sticas f√≠sicas de la zona de estudio. Con estos valores se simula el modelo matem√°tico de drenaje pluvial urbano, calculando el caudal de dise√Īo, as√≠ como, los tirantes m√°ximos. Este modelo es calibrado y validado hasta obtener resultados con buen desempe√Īo hidr√°ulico y que cumple con las normativas vigentes. Con todo esto se procede a dise√Īar los elementos del drenaje, para finalmente, plantear posibles soluciones sostenibles al problema de inundaciones en zonas urbanas, que complementan el sistema de drenaje pluvial urbano dise√Īado

    Metaphors of London fog, smoke and mist in Victorian and Edwardian Art and Literature

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    Julian Wolfreys has argued that after 1850 writers employed stock images of the city without allowing them to transform their texts. This thesis argues, on the contrary, that metaphorical uses of London fog were complex and subtle during the Victorian and Edwardian periods, at least until 1914. Fog represented, in particular, formlessness and the dissolution of boundaries. Examining the idea of fog in literature, verse, newspaper accounts and journal articles, as well as in the visual arts, as part of a common discourse about London and the state of its inhabitants, this thesis charts how the metaphorical appropriation of this idea changed over time. Four of Dickens's novels are used to track his use of fog as part of a discourse of the natural and unnatural in individual and society, identifying it with London in progressively more negative terms. Visual representations of fog by Constable, Turner, Whistler, Monet, Markino, O'Connor, Roberts and Wyllie and Coburn showed an increasing readiness to engage with this discourse. Social tensions in the city in the 1880s were articulated in art as well as in fiction. Authors like Hay and Barr showed the destruction of London by its fog because of its inhabitants' supposed degeneracy. As the social threat receded, apocalyptic scenarios gave way to a more optimistic view in the work of Owen and others. Henry James used fog as a metaphorical representation of the boundaries of gendered behaviour in public, and the problems faced by women who crossed them. The dissertation also examines fog and individual transgression, in novels and short stories by Lowndes, Stevenson, Conan Doyle and Joseph Conrad. After 1914, fog was no more than a crude signifier of Victorian London in literature, film and, later, television, deployed as a cliche instead of the subtle metaphorical idea discussed in this thesis

    Towards a sociology of conspiracy theories: An investigation into conspiratorial thinking on Dönmes

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    This thesis investigates the social and political significance of conspiracy theories, which has been an academically neglected topic despite its historical relevance. The academic literature focuses on the methodology, social significance and political impacts of these theories in a secluded manner and lacks empirical analyses. In response, this research provides a comprehensive theoretical framework for conspiracy theories by considering their methodology, political impacts and social significance in the light of empirical data. Theoretically, the thesis uses Adorno's semi-erudition theory along with Girardian approach. It proposes that conspiracy theories are methodologically semi-erudite narratives, i.e. they are biased in favour of a belief and use reason only to prove it. It suggests that conspiracy theories appear in times of power vacuum and provide semi-erudite cognitive maps that relieve alienation and ontological insecurities of people and groups. In so doing, they enforce social control over their audience due to their essentialist, closed-to-interpretation narratives. In order to verify the theory, the study analyses empirically the social and political significance of conspiracy theories about the Dönme community in Turkey. The analysis comprises interviews with conspiracy theorists, conspiracy theory readers and political parties, alongside a frame analysis of the popular conspiracy theory books on Dönmes. These confirm the theoretical framework by showing that the conspiracy theories are fed by the ontological insecurities of Turkish society. Hence, conspiracy theorists, most readers and some political parties respond to their own ontological insecurities and political frustrations through scapegoating Dönmes. Consequently, this work shows that conspiracy theories are important symptoms of society, which, while relieving ontological insecurities, do not provide politically prolific narratives

    Globalisation and pollinators: pollinator declines are an economic threat to global food systems

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    1. Trade in animal-pollinated crops plays an important role in global food systems: in many low-income countries, export of pollinated crops such as coffee and cocoa plays a significant role in livelihoods, while food systems in many higher income nations depend on international trade in these crops to satisfy their local demands. Losses of pollination services therefore pose a significant risk to economies beyond the area directly affected. 2. Using a simple extension of a common economic model, we explore which countries are most affected by a loss of pollination services in three case study groups of 25 countries that are vulnerable to different risks: pesticide use, natural disasters and economic debts. 3. In all three cases, large, developed economies such as the United Kingdom, Germany and Japan, are estimated to suffer the greatest economic losses, even if pollinator losses only affect smaller, less-developed economies. 4. In cases where higher income countries are affected by pollinator losses, there is a significant shift in the value of global pollinated crop production towards other large, unaffected countries. 5. Our findings highlight the need for richer countries to invest in pollinator conservation beyond their own borders to maintain resilient food systems. We provide suggestions for further economic research to better understand and identify system vulnerabilities to pollinator losses

    The Grapes of Wrath: An Artful Jurisprudence

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    By documenting the harsh realities of the era, The Grapes of Wrath (‚ÄėGOW‚Äô) calls to mind those distressing UN Country Reports that both describe and denounce avoidable landscapes of poverty, hunger, homelessness, and dispossession. Steinbeck embeds the novel‚Äôs harrowing images within an unforgiving framework of human rights violations, most of which flow directly from human greed. The novel‚Äôs prescient yet timeless warnings speak not only to the various humanitarian crises brought about by climate change and unethical commercial practices, but also to many ongoing, perennial global atrocities: corrupt political regimes, gendered injustices, ethnic cleansing, and displacement of entire populations. It is landscapes such as these that still serve to both spark and underpin refugee existence: the need for a compassionate system of asylum-granting, firmly grounded in human rights law, clearly remains as urgent now as it was in Steinbeck‚Äôs time. As witnesses to such chronic disregard for human dignity, readers of the novel are not only tasked with judging those responsible: we must also evaluate the perennial failings of the various global and domestic systems that have enabled and perpetuated such egregious rights violations. The final scene, drenched in symbolism, still serves as a quasi-courtroom: before the bared breast of a Lady Justice figure we become jurists, and cannot help apportioning blame for all that has been witnessed over the course of the Joad‚Äôs journeying. A close reading now, almost a century later, serves as a timely reminder that similar atrocities continue: migrant and refugee populations remain especially vulnerable, not least where they have been displaced by poverty or political crises from all that was once familiar. This article argues that the novel‚Äôs central focus on ‚Äúsocial realism‚ÄĚ demands much in the way of ‚Äúmoral and emotional effort‚ÄĚ (Benson, 9) from the reader: we should leave the book with nothing less than a highly ‚Äúactive compassion for the dispossessed‚ÄĚ (Wyatt, 12). It is perhaps best viewed as a collection of first-hand witness testimonies, akin to those gathered and collated by the United Nations (UN) various Committees and which serve to reveal, record, and address the horrendously fine detail of abject human rights violations and their impacts upon the most vulnerable. It is Steinbeck‚Äôs ‚Äúconsistently catchy eyewitness quality‚ÄĚ (De Mott, xiii) which both brings and retains this timeless sense of urgency and immediacy, without directing any clear response: it is up to the conscience of the individual reader to determine how best to process or address the various challenges presented
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