The National Bureau of Standards conducted outdoor durability tests on eight different types of commercially available flat plate solar collectors. The test results for five types of collectors are analyzed. The purpose of the test program was to investigate the feasibility of determining the durability of materials by measuring collector thermal efficiency at specified intervals. The important material properties include the solar absorptance and long wave emittance of the absorber surface, solar and long wave transmittance of the cover material and the thermal conductivity of the insulation. Tests were conducted by three independent testing laboratories located in Phoenix, Arizona, Cape Canaveral, Florida, and Palo Alto, California. The test sites were chosen to investigate the effects of the various environmental conditions found in the United States on collector degradation. Three test series were considered to study the effect of various operating conditions on collector degradation. The collectors were exposed to the environment for up to 240 days. The thermal performance test results did not reveal significant degradation in the performance parameters, F_r(T_α) and F_rU_L, of the collectors considered. Any degradation that may have occurred was overshadowed by experimental uncertainty. The test results did not depend on test series, geographic location or season of the year. Referring the test results to a common set of weather conditions did not reduce the scatter in the results. / Master of Science

Call number: LD2668 .T4 1978 J35 / Master of Science

This paper presents analytical and experimental studies on optimization of the gas delivery and current collection system in a proton exchange membrane (PEM) fuel cell for the objective of reducing ohmic loss, thereby achieving higher power density. Specifically, the dimensions of current collection ribs as well as the rib distribution were optimized to get a maximized power density in a fuel cell. In the modeling process, the power output from a fixed area of membrane is calculated through analysis of an electrical circuit simulating the current from electrochemical reaction flowing to the current collectors. Current collectors of two-dimensional ribs and three-dimensional pillars were considered. Analyses found that three-dimensional pillars allow higher power density in a PEM fuel cell. Considering the mass transfer enhancement effect, three-dimensional pillars as current collectors in gas flow field may be a good choice if the fuel cell operates at low current density and there is no liquid water blocking the flow channels. The analyses did not consider the existence of liquid water, meaning the current density is not very high. The study concluded that decreasing the size of both the current collector and its control area yields a significant benefit to a higher power density. A preliminary experimental test in a PEM fuel cell has verified the conclusion of the analytical work.

published_or_final_version / Fine Arts / Doctoral / Doctor of Philosophy

This research aims to evaluate the construction of Turkey and the “Oriental other” in Colonial Britain at the turn of the 20th century through a post-colonial theoretical perspective presented through the analysis of various data regarding the 'Aegean & Hittite Collections' gallery at the Public Museum Liverpool (now World Museum) from 1931 till the Blitz of June 1941. The sources include undocumented archives such as field notes, postcards and correspondence and what remains of the 'Garstang Hittite Collection' held at National Museums Liverpool (NML). A full investigation into how the collection was put together through curatorial and archaeological methods, what it consisted of, why these specific objects were chosen and what value were attributed by the collector and curators of the time along with gallery pals and visitors’’ guide book will allow for valid reconstruction and re-interpretation of the “Aegean & Hittite Gallery”. Furthermore I shall also explore the value of displaying a substantial collection of Hittite casts at a time when such objects were tools for Classical and Neo-Classical artistic education, understood by contemporary British society to be the pinnacle of artistic achievement. This Neo-Hittite imagery had no artistic value attributed to it and was displayed in a context of educational value for the lower social classes who could not perceive the ‘high’ arts involved in Classical Greek culture that had been adopted by aristocratic Britain as the paradigm for its own colonial identity; popularly reinforced nationally through various media, including exhibitions such as this, and also internationally through neo-Classical architectural design e.g. The Liverpool Acropolis. My thesis also relates the above premises with the life and work of Prof. John Garstang, his role within the Institute of Archaeology in Liverpool, his contribution to the “Aegean & Hittite Collections' gallery, his role as archaeological agent for private collectors, his work ethics and methodologies and his later role as establisher of British archaeological institutes in Jerusalem, Amman and Ankara. Academic reception of Hittite archaeology in Britain and the newly-formed nation-state of Turkey following the abolition of Ottoman rule in 1923 will also be considered especially regarding Garstang’s standing as a British archaeologist contributing to the Kemâlist Turkish capital city of Ankara in 1947. This research will place the Hittite Gallery’s contents and displays within their archaeological, cultural and intellectual contexts but also aims to explore the political use of contemporaneous Hittite archaeological negotiation both in Britain and Turkey at such a tumultuous time bound together through the work of Prof. John Garstang.

Este ensaio é disparado pelos processos musicais que permeiam a jornada de trabalho de catadores de lixo em São Paulo. Neste cotidiano em meio ao lixo, estes abrem brecha para notas musicais, ritmos corridos e assobios melódicos. O objetivo desta pesquisa consiste em compreender, desta forma, o quê cantam estes trabalhadores, e a relação destes cantos com o cotidiano dos mesmos; quero, então, buscar um entendimento da música dentro do contexto urbano do lixo. Este ensaio, portanto, se trata de um estudo etnográfico sobre usos da música no ofício destes trabalhadores e seus desdobramentos no cotidiano destes. Há mais de um milhão de catadores no Brasil. Nas ruas de São Paulo, mais de vinte-cinco mil catadores de lixo reciclável sobrevivem à margem da cidade. Busco, neste trabalho, investigar o quê cantam e como cantam. Assim, contextualizando o fazer musical destes trabalhadores, proponho nesta pesquisa uma etnografia que busque diálogos entre a música, o silêncio e a corporalidade deles, pensando a música no trabalho destes catadores, e como o que cantam e contam diz sobre o que são socialmente. / This essay is triggered by the musical processes that permeate the work day of waste collectors in São Paulo. In the daily routine amidst the waste, they open themselves to musical notes, rushed rythms, and melodic whistles. The objective, here, is to comprehend, in this way, what these workers sing, and the relation between this singing to their daily lives; I seek an understanding of music inside the urban contexto of waste. Therefore, this research is an ethnographic study about the uses of music in the occupation of these workers and their repercussions in their day-to-day. There is more than a million waste collectors in Brazil. In the streets of São Paulo, more than twenty-five thousand survive in the edge of the city. In this essay, I look into what they sing and how they sing. Thus, by contextualizing theis music-making, I propose an ethnography that pursuits an intersection between music, silence and corporeality, through the thought of music in their work-days, and how the music tells about what these workers are socially.

Orientador: Vicente Luiz Scalon / Coorientador: Alcides Padilha / Banca: Celso Luiz da Silva / Banca: Ismael de Marchi Neto / Banca: Rodrigo Correa da Silva / Resumo: A mudança na geração de energia através de fontes não renováveis para fontes renováveis é uma grande preocupação mundial e nacional, que tem impulsionado pesquisas e desenvolvimentos de tecnologias na área de energia renovável. Neste cenário, a energia solar é uma excelente alternativa, por ter um grande potencial e diversas aplicações. Com isso, este trabalho tem o objetivo de analisar melhorias na eficiência de coletor solar plano, equipamento utilizado no aquecimento de água através da energia solar, ao adicionar barreiras na cavidade de ar confinado entre a sua placa absorvedora e a sua cobertura de vidro. As barreiras bloqueiam o fluxo de ar, provocado pela convecção interna, diminuindo as perdas de calor. A análise foi realizada em quatro coletores, nos quais foram adicionados de uma a quatro barreiras e comparados com um coletor sem barreira como referência. Para isso, foi construída uma bancada de teste com todos equipamentos necessários para obter a eficiência em coletor solar plano. Os resultados dos ensaios mostraram que não houve uma variação significativa da absorção de radiação solar, já que a eficiência máxima manteve-se inalterada. Porém, houve uma diminuição da perda de calor ao adicionar as barreiras, sendo esse resultado diretamente relacionado a inclinação da curva de eficiência usada na análise de coletor solar plano. Os resultados mostram que a inclinação varia em -2,05%, -5,12% e 2,94%, para duas a quatro barreiras, respectivamente. Portanto, as barreir... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The shift in power generation from non-renewable sources to renewable sources is a major global and national concern that has driven research and development of renewable energy technologies. In this scenario, the solar energy is an excellent alternative, for having great potential and diverse applications. With this, the objective of this work is to analyze improvements in the efficiency of solar collector flat, equipment used in heating water through solar energy, by adding barriers in the confined air cavity between its absorber plate and its glass cover. The barriers block the flow of air, caused by internal convection, reducing heat losses. The analysis was performed on four collectors, in which one to four barriers were added and compared with a barrierless collector as a reference. For this, a test bench was built with all the necessary equipment to obtain the efficiency in the flat solar collector. The results of the tests showed that there was no significant variation in the absorption of solar radiation since the maximum efficiency remained unchanged. However, there was a decrease of the heat loss when adding the barriers, being this result directly related to the slope of the curve of efficiency used in the analysis of flat solar collector. The results show that the slope varies by -2.05%, -5.12% and 2.94% for two to four barriers, respectively. Therefore, the barriers reduce the heat loss to the medium, with an optimal number of barriers for each flat solar collector project. / Doutor

This thesis is about four historical collections of Haida argillite carvings now at the National Museum of Scotland, the University of Aberdeen Museums and the Perth Museum and Art Gallery. Since the early nineteenth century Haida artists have carved argillite, a carbonaceous shale, into objects featuring Haida and European-inspired motifs, for trade or sale to non-Haida others. Scots Colin Robertson, William Mitchell, James Hector and John Rae acquired argillite as part of broader collections from the Northwest Coast of Canada made during the middle decades of the nineteenth century. Each of these men was employed by, or affiliated with the Hudson’s Bay Company. This thesis questions how the meanings and statuses of these objects, collected and deposited in Scottish museums between the 1820s and 1860s, have changed over the nearly two centuries of their existence. Research at these three museums, and at British and Canadian archives, provided the material that shed light on the historical circumstances of the approximately 30 objects constituting these collections. Semi-structured interviews with Haida carvers, community members and experts, and with museum curators elicited insights into the ways these objects are made meaningful today. The thesis examines the collections in four key contexts. First, it explores the ways in which they have been displayed and interpreted at the three museums, shedding light on the trajectories by which museums have represented the objects of others. Secondly, it describes the context in which the argillite carvings were produced, circulated and collected by sketching the social and political character of the Northwest Coast as it transformed through the decades of the fur trade to European colonization. How these objects transformed in status and value according to the agendas of their collectors is the third context, which reflects the character of relationships between Indigenous peoples and newcomers. Finally, I resituate these collections in the context of contemporary Haidas’ perspectives on the value and meaning of argillite carving(s), and propose that these objects can be understood as “inalienable commodities.” The argillite carvings in these Scottish museum collections are objects of exchange, produced and circulated in the contact zone of the mid-nineteenth century Northwest Coast. As such, they are windows into relationships between Indigenous and European people during this period. Collected as curiosities but remade into objects of science, biography and art, this study traces their shifting statuses as they have moved through various regimes of value. This thesis therefore characterizes the exchanges that have occurred around these objects as ongoing and dynamic.

Management of cultural heritage depends on ethical decisions. These ethical decisions will bestow the heritage with a value and will protect it by establishing legal frameworks. However, sometimes, these legal frameworks can have the opposite effect and damage the heritage if they are not continuously revised and updated according to the new ethical challenges of the development in the field of cultural heritage. Although underwater cultural heritage has a legislative element that protects it from the relatively minor threat of treasure hunters, it pays little attention to ethical concerns that expose the heritage to more serious menaces. This study proposes (contrary to the traditional view of land heritage management as an example to underwater heritage management) a new vision where underwater cultural heritage challenges principles that in land heritage management have been taken for granted: valuation, use, management and preservation. The work presents four case studies as models both for illustrating the key ethical issues and for offering solutions: the violin of the Titanic, ancient lead for particle physics experiments, watery graves and the effects of climate change on underwater cultural heritage. Finally this work explores themes of value, ethics and the process in which a common object becomes heritage.

Conservators treat and repair a huge array of damaged and degrading materials on a regular basis. As such, there are many techniques and protocols in place to deal with these problems successfully, be that via preventative or interventive methods. However, there is need for new and innovative techniques that offer long term stabilisation to materials and objects that are prevalent within museum collections. As an alternative to some of these conservation techniques, hydration with supercritical carbon dioxide was investigated here. Both modern and historic, hardwood and softwood samples were successfully hydrated using this technique. The addition of a co-solvent (methanol) to the supercritical fluid solvent stream was used as a method to increase the solubility of water in carbon dioxide, and therefore improve levels of hydration. To evaluate the extent of any damage being caused during the supercritical fluid treatment, microstructural and macrostructural analytical techniques were carried out. The supercritical hydration technique allowed historic wood to be hydrated and stabilised. Strength properties were seen to be maintained or improved after the supercritical treatment, providing conservators with a viable method of hydration. A feasibility study looking at the cleaning and characterisation of historic leather samples was investigated using spectroscopic methods. The sensitivity of Diffuse Reflectance Infrared Fourier Transform spectroscopy on historic leather was explored. Additionally, changes in elemental composition on the surface of the leather were monitored using Scanning Electron Microscopy Energy Dispersive spectroscopy. Cleaning historic leather via a supercritical carbon dioxide solvent stream showed the greatest potential for future work. However, the characterisation of unattributed historic leather is a vast and complex task that would require the expertise of a leather conservator, if the investigation were to be continued.