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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Faktorer som påverkar möjligheterna att använda träfiberisolering / Factors affecting the possibilities of using wood fiber insulation

Petrovic, Aleksandra, Olsson, Wilma January 2022 (has links)
The global climate situation today is strained, leading to both the need and the interest for the use of non-polluting materials to increase in the building sector. In Sweden, this sector accounts for about 18% of the country’s total domestic emissions of greenhouse gases, of which 55% occurs from heat losses in buildings. The need for increasing energy efficiency and using well-insulating and environmentally friendly materials can therefore be considered necessary. Bio-based materials such as wood fiber insulation are becoming increasingly more available on the market. These materials have an environmental advantage compared to mineral wool but are still being used on a smaller scale. The purpose of this study is to analyze and examine technical differences and other reasons why wood fiber insulation is being used to a lesser extent compared to mineral wool. Both a literature and an interview study were conducted to identify these reasons. The results showed differences in thermal conductivity and fire resistance between wood fiber insulation and mineral wool. Both types of mineral wools performed better in both categories. Several other factors besides technical differences were discovered to affect the use of wood fiber insulation. Respondents described the building sector as conservative, and slow in the process of implementing new materials. Concerns were raised about performance regarding fire and the durability of the wood fiber insulation over time. Price, low or non-existing interest amongst customers were two other factors highlighted in the interview study. All respondents viewed wood fiber insulation as an untested material and expressed a need for better documentation and guidelines to feel safe using or recommending the product. It was found in this study that the awareness and knowledge about the material amongst the interviewers was quite diverse. This may be due to low interest, low demand, or lack of marketing regarding wood fiber insulation. / Klimatsituationen i världen idag är ansträngd, och både intresset och behovet av att utveckla och använda miljövänliga material och produkter inom byggsektorn ökar. I Sverige står denna sektor för cirka 18% av landets totala inhemska utsläpp av växthusgaser och av dessa utgör omkring 55% uppvärmning för byggnader. Den största mängden energi går förlorad genom otillräckligt isolerade byggnader, vilket understryker behovet av att åtgärda dessa brister. Idag används huvudsakligen mineralullsisolering i Sverige för byggnation. Produktmarknaden erbjuder däremot också biobaserad isolering, där träfiberisolering är ett exempel. Träfiberisoleringen har fler miljömässiga fördelar jämfört med mineralull, men nyttjas i mindre skala. Denna studie syftar därför till att skapa förståelse och undersöka varför träfiberisolering används i mindre utsträckning. Målet är att identifiera samt redovisa tekniska och andra skäl till att användningen är begränsad. Två metoder tillämpades i studien för att kunna nå dess syfte och mål. Den ena var en litteraturstudie där skillnader mellan träfiberisolering och mineralull jämfördes på en teknisk nivå. Den andra var en intervjustudie med åtta nyckelaktörer i byggbranschen, som genomfördes för att erhålla en uppfattning om vilka faktorer som påverkade valet av isolering. Den tekniska jämförelsen utgick ifrån kategorierna värmeisolerande förmåga, samt brand-, fukt- och ljudisolerande aspekter. Fyra olika isoleringsprodukter från fyra olika tillverkare studerades, varav två var träfiberisolering och två var oorganiska mineralullstyper, i form av stenull och glasull.   Studiens tekniska jämförelse visade att träfiberisoleringen presterade sämre än mineralullen både gällande värmekonduktivitet och värmemotstånd. Den brandtekniska klassen för mineralull var klass A1, vilket är den högsta, medan träfiberisoleringen hade den lägsta klassificeringen med en E-klass. För fuktegenskapen ånggenomsläpplighet visade båda typer av mineralull samma värde, medan träfiberisoleringen hade lägre värden. Vattenabsorptionen för korttid och långtid, samt den ljudisolerande förmågan, kunde inte jämföras eftersom ingen prestanda var deklarerad i dessa kategorier för någon av produkterna. Utöver jämförelsen av teknisk prestanda undersöktes även skäl till att byggbranschens aktörer ofta väljer att använda mineralull hellre än träfiberisolering. Det konstaterades att flera faktorer än de tekniska skillnaderna påverkar i frågan. Flera aktörer påpekade att branschen var konservativ och det var en långsam process att implementera nya material. En annan faktor som lyftes av aktörerna var oro kring brandförmågan och hur den tekniska prestandan håller över tid. Prisskillnaden, samt att intresset för träfiberisolering hos beställare var lågt eller obefintligt, var två ytterligare anledningar som identifierades. Samtliga aktörer uttryckte också uppfattningen om träfiberisoleringen som ett obeprövat material med för låg dokumentationsgrad för att känna trygghet i att använda produkten. Fler anledningar kring träfiberisoleringens användning upptäcktes än de som från början fanns hypoteser kring. En av de större orsakerna var osäkerhetsfaktorer kring dokumentation och tekniska egenskaper för träfiberisolering. Andra skäl var branschens konservatism och långsamma utveckling, behov av trygghet i prestanda av garantiskäl, och viss misstro gällande tillverkares uttalanden om produkten. Generellt visade aktörerna spridd medvetenhet och kunskap kring materialet, vilket kan bero på lågt intresse, låg efterfrågan eller bristande marknadsföring av träfiberisolering.
2

Pós-tratamento de esgoto sanitário com biofiltro aerado submerso preenchido com carvão granular: desempenho técnico e estudo de viabilidade econômica / Wastewater post-treatment with submerged aerated biofilter filled with granular coal: technical performance and economic viability study

Fontana, Hallan 08 February 2008 (has links)
Neste trabalho avaliou-se o desempenho técnico e a viabilidade econômica do biofiltro aerado submerso preenchido com carvão granular antracitoso, empregado no pós-tratamento de efluente proveniente de reator anaeróbio de fluxo ascendente com manta de lodo. Os biofiltros experimentais utilizados no trabalho, com volume reacional de 47 L, operaram por 200 dias, com tempos de detenção hidráulica de 5 e 7,5 h. Constatou-se a viabilidade técnica em relação à remoção de matéria orgânica e nitrogênio amoniacal. O BF1 (TDH = 5 h), apresentou eficiências médias na remoção de \'DQO IND.f\', \'DBO IND.5\' e nitrogênio amoniacal de 62%, 46% e 89%, respectivamente, com valores médios de efluente de 25 \'+ OU -\' 11 mg\'DQO IND.f\'/L, 36 \'+ OU -\' 29 mg\'DBO IND.5\'/L e 4 \'+ OU -\' 9 mg N-\'NH IND.3\'/L. Por outro lado, o BF2 (TDH = 7,5 h), com desempenho superior, apresentou eficiências médias na remoção de \'DQO IND.f\', \'DBO IND.5\' e nitrogênio amoniacal de 68%, 95% e 89%, respectivamente, com valores médios de efluente de 21 \'+ OU -\' 12 mg\'DQO IND.f\'/L, 3 \'+ OU -\' 3 mg\'DBO IND.5\'/L e 6 \'+ OU -\' 12 mg N-\'NH IND.3\'/L. Os sistemas combinados UASB+BF apresentaram eficiências globais médias acima de 87% para DQO filtrada. Na análise da viabilidade econômica, o custo do leito filtrante de carvão representou, em média, 23% do custo total de implantação. Para o horizonte de projeto de 20 anos e taxa de juros de 11% ao ano, as receitas mínimas estimadas para sistemas de pós-tratamento com biofiltro preenchido com carvão foram de R$ 0,19; R$ 0,20; R$ 0,22 e R$ 0,24 por metro cúbico tratado, para populações de 200.000, 100.000, 50.000 e 25.000 habitantes respectivamente, sem considerar o custo com o tratamento do lodo gerado neste tratamento. / This research refers to technical performance and economic viability of submerged aerated biofilter with bed granular anthracite coal, employed in the post-treatment of effluent from upflow anaerobic sludge bed reactor. The experimental biofilters used in this research, with 47 L reaction volume, were loaded for 200 days with hydraulic retention time of 5 and 7.5 h. Technical feasibility regarding the removal of organic matter and ammonia nitrogen was confirmed. BF1 (HRT = 5 h) removal efficiencies of filtered COD, BOD and ammonia nitrogen were 62%, 46% and 89%, respectively, with average effluent concentration of 25 \'+ OU -\' 11 mg \'COD IND.f\'/L, 36 \'+ OU -\' 29 mg \'BOD IND.5\'/L e 4 \'+ OU -\' 9 mg \'NH IND.3\'/L. Moreover, BF2 (HRT = 7.5 h), with higher performance, achieved removal efficiencies 68%, 95% and 89% of filtered COD, DBO and ammonia nitrogen respectively, with average effluent concentration of 21 \'+ OU -\' 12 mg \'COD IND.f\'/L, 3 \'+ OU -\' 3 mg \'BOD IND.5\'/L and 6 \'+ OU -\' 12 mg \'NH IND.3\'/L. Combined systems UASB+BF achieved average overall efficiencies above 87% to filtered COD. Concerning economic feasibility study, the coal bed represented, on average, 23% of the total deployment cost. Within a twenty-year-project horizon and 11% of annual interest rate, the estimated minimum revenues for post-treatment system with submerged aerated biofilter with bed coal were R$ 0,19; R$ 0,20; R$ 0,22 and R$ 0,24 - brazilian real - per cubic meter of wastewater treated for 200,000, 100,000, 50,000 and 25,000 inhabitants respectively, without evaluating treatment cost of sludge generated in this system.
3

Pós-tratamento de esgoto sanitário com biofiltro aerado submerso preenchido com carvão granular: desempenho técnico e estudo de viabilidade econômica / Wastewater post-treatment with submerged aerated biofilter filled with granular coal: technical performance and economic viability study

Hallan Fontana 08 February 2008 (has links)
Neste trabalho avaliou-se o desempenho técnico e a viabilidade econômica do biofiltro aerado submerso preenchido com carvão granular antracitoso, empregado no pós-tratamento de efluente proveniente de reator anaeróbio de fluxo ascendente com manta de lodo. Os biofiltros experimentais utilizados no trabalho, com volume reacional de 47 L, operaram por 200 dias, com tempos de detenção hidráulica de 5 e 7,5 h. Constatou-se a viabilidade técnica em relação à remoção de matéria orgânica e nitrogênio amoniacal. O BF1 (TDH = 5 h), apresentou eficiências médias na remoção de \'DQO IND.f\', \'DBO IND.5\' e nitrogênio amoniacal de 62%, 46% e 89%, respectivamente, com valores médios de efluente de 25 \'+ OU -\' 11 mg\'DQO IND.f\'/L, 36 \'+ OU -\' 29 mg\'DBO IND.5\'/L e 4 \'+ OU -\' 9 mg N-\'NH IND.3\'/L. Por outro lado, o BF2 (TDH = 7,5 h), com desempenho superior, apresentou eficiências médias na remoção de \'DQO IND.f\', \'DBO IND.5\' e nitrogênio amoniacal de 68%, 95% e 89%, respectivamente, com valores médios de efluente de 21 \'+ OU -\' 12 mg\'DQO IND.f\'/L, 3 \'+ OU -\' 3 mg\'DBO IND.5\'/L e 6 \'+ OU -\' 12 mg N-\'NH IND.3\'/L. Os sistemas combinados UASB+BF apresentaram eficiências globais médias acima de 87% para DQO filtrada. Na análise da viabilidade econômica, o custo do leito filtrante de carvão representou, em média, 23% do custo total de implantação. Para o horizonte de projeto de 20 anos e taxa de juros de 11% ao ano, as receitas mínimas estimadas para sistemas de pós-tratamento com biofiltro preenchido com carvão foram de R$ 0,19; R$ 0,20; R$ 0,22 e R$ 0,24 por metro cúbico tratado, para populações de 200.000, 100.000, 50.000 e 25.000 habitantes respectivamente, sem considerar o custo com o tratamento do lodo gerado neste tratamento. / This research refers to technical performance and economic viability of submerged aerated biofilter with bed granular anthracite coal, employed in the post-treatment of effluent from upflow anaerobic sludge bed reactor. The experimental biofilters used in this research, with 47 L reaction volume, were loaded for 200 days with hydraulic retention time of 5 and 7.5 h. Technical feasibility regarding the removal of organic matter and ammonia nitrogen was confirmed. BF1 (HRT = 5 h) removal efficiencies of filtered COD, BOD and ammonia nitrogen were 62%, 46% and 89%, respectively, with average effluent concentration of 25 \'+ OU -\' 11 mg \'COD IND.f\'/L, 36 \'+ OU -\' 29 mg \'BOD IND.5\'/L e 4 \'+ OU -\' 9 mg \'NH IND.3\'/L. Moreover, BF2 (HRT = 7.5 h), with higher performance, achieved removal efficiencies 68%, 95% and 89% of filtered COD, DBO and ammonia nitrogen respectively, with average effluent concentration of 21 \'+ OU -\' 12 mg \'COD IND.f\'/L, 3 \'+ OU -\' 3 mg \'BOD IND.5\'/L and 6 \'+ OU -\' 12 mg \'NH IND.3\'/L. Combined systems UASB+BF achieved average overall efficiencies above 87% to filtered COD. Concerning economic feasibility study, the coal bed represented, on average, 23% of the total deployment cost. Within a twenty-year-project horizon and 11% of annual interest rate, the estimated minimum revenues for post-treatment system with submerged aerated biofilter with bed coal were R$ 0,19; R$ 0,20; R$ 0,22 and R$ 0,24 - brazilian real - per cubic meter of wastewater treated for 200,000, 100,000, 50,000 and 25,000 inhabitants respectively, without evaluating treatment cost of sludge generated in this system.
4

Représentations et usages des armements contemporains : pour une socio-anthropologie de la complexité technique / Contemporary weapons uses and representations : a social anthropology of technical complexity

Lefeez, Sophie 12 September 2014 (has links)
En Irak et en Afghanistan, les EEI (engins explosifs improvisés) ont durement atteint les matériels militaires et les soldats occidentaux. Cette confrontation entre haute et faible technicité soulève la question des choix techniques. Les rapports institutionnels et les acteurs mettent habituellement en avant deux raisons pour justifier le choix de la haute technicité : la nécessité de jouir d'une supériorité technique sur l'adversaire pour vaincre, et l'imprévisibilité des futures interventions militaires. L'étude de terrain sur le système de missile antichars Milan et son successeur temporaire, le Javelin, montre que les combattants ne lient pas la polyvalence à la technicité, et que leur travail est en train d'être fonctionnalisé. En effet, les concepteurs (États-majors, DGA, industriels) ont recours à l'approche systémique pour améliorer la cohérence entre matériels et accroître la performance d'ensemble. Cette approche s'inspire de la rationalité managériale, qui pénètre de plus en plus le milieu militaire. Or, les combattants réinventent souvent leurs matériels du fait du caractère imprédictible des conflits, et la puissance née de cette rationalité gestionnaire se révèle sur le terrain en partie fragile et déréalisée. La complexité ressentie par les acteurs à propos des armements contemporains serait alors le révélateur d'une évolution technique hors sol et hors du temps commun, distante des êtres humains concrets. / In Iraq and in Afghanistan, IEDs (improvised explosive devices) severely hit Western military equipment and personnel. This high-tech / low-tech face-off raises questions about technical choices. Institutional reports and actors usually justify the choice of high technicity on two grounds: the need to have technical superiority over rivals to win and the uncertainty surrounding future military interventions. A ground study about the Milan antitank missile system and his temporary successor, the Javelin, revealed versatility is not related to technicity in users' mind, and showed servants are being functionalised. Indeed, designers (military HQs, DGA, private industries) have opted for a systemic approach to increase consistency among equipment and gain in overall performance. Users have got considered as a piece of the system — serving a function. This approach owes much to managerial rationality, which has pervaded the military organisation to a high degree. However, fighters often re-invent their equipment role due to war unpredictability, while power delivered by managerial rationality proves to be partly fragile and derealised. Complexity actors detect about contemporary weapons seems to be a pointer of a technical evolution carried out above ground and beyond time, remote from concrete human beings.

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