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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.
101

conception des scénarios de recyclage pilotée par l’évaluation des performances des procédés / design of recycling pathways driven by the evaluation of process performance

Grimaud, Guilhem 18 February 2019 (has links)
La planète se trouve dans un état de dégradation des écosystèmes, d’épuisement des ressources, de tension démographique et d’urgence climatique particulièrement préoccupant. Le découplage de la consommation de matières premières avec l’activité économique est indispensable. En réduisant la pression sur la raréfaction des matières premières, l’économie circulaire peut participer à la lutte contre le dérèglement climatique. Bien que le recyclage ne puisse solutionner seul l’épuisement des ressources, il est indispensable de mettre en œuvre des solutions pour régénérer les matières présentes dans nos déchets. Or l’organisation actuelle de la filière de fin de vie ne semble pas répondre aux besoins de l’économie-monde.Le premier challenge pour déployer des solutions de recyclage en économie circulaire repose sur l’évaluation de la performance des scénarios de recyclage. La méthodologie proposée repose sur plusieurs outils d’analyse : analyse de flux de matières (MFA), Analyse de Cycle de Vie (ACV) et Analyse de coûts (LCC) dans un cadre technique de référence basé sur l’évaluation des écotechnologies (ETV). Ce travail s’applique en partenariat avec la société MTB. Trois axes de performances ont été retenus : technique, économique et environnemental.Cette évaluation multicritères, intégrés dans la démarche de conception de MTB, permet une communication sous la forme d’indicateurs clés de performances (KPI). Ces indicateurs supplémentaires permettent de quantifier rapidement l’éco-efficience d’un scénario, pour accompagner la prise de décisions des concepteurs lors de la construction de l'offre et du développement des solutions scénarios de recyclage. / The planet is in a particularly worrying state of degradation of ecosystems, depletion of resources, demographic tension and a climate emergency. The decoupling of the consumption of raw materials with economic activity is a relevant action lever. By reducing the pressure on the scarcity of raw materials, the circular economy can participate in the fight against climate change. Although recycling alone cannot solve resource depletion, it is essential to implement solutions to regenerate the materials present in our waste. However, the current organization of the end-of-life sector does not seem to meet the needs of the world economy.The first challenge in deploying recycling solutions in the circular economy is based on evaluating the performance of recycling scenarios. The proposed methodology is based on several analytical tools: Material Flow Analysis (MFA), Life Cycle Assessment (LCA) and Life Cost Costing (LCC) in a technical reference framework based on the evaluation of environmental technologies (ETV). This work applies in partnership with the company MTB. Three performance axes were chosen: technical, economic and environmental.This multi-criterion assessment, integrated into the MTB design process, allows communication in the form of key performance indicators (KPI). By providing additional performance indicators it is possible to quickly quantify the eco-efficiency, to support decision-making by designers during the development of the recycling pathway.
102

Avaliação ambiental do processo produtivo de aparelhos de ar-condicionado utilizando a ferramenta Análise do Ciclo de Vida (ACV)

Freitas, Daisy Amed das Chagas de 22 July 2013 (has links)
Made available in DSpace on 2015-04-22T22:11:01Z (GMT). No. of bitstreams: 1 Daisy Amed das Chagas de Freitas.pdf: 5797839 bytes, checksum: 5037fb54ff3fc2e2be975b2335d845d3 (MD5) Previous issue date: 2013-07-22 / The industry of air conditioning is a major consumer of raw materials and strong generator of waste. The production process and each step in the life cycle of such products cause impacts contributing to environmental degradation. The air conditioning is one of the leading manufactured products in the Industrial Pole of Manaus and the most sold in the local market due to high temperatures, typical of the region. Therefore, this study evaluated the environmental aspects and potential impacts involved in the production process of window air conditioner, using the tool of Life Cycle Assessment (LCA). LCA is a technique for environmental management based on inventory construction that considers the inputs of raw materials and energy, and waste emissions associated with the production process. In this context, a case study has been conducted in the Amazon Electrolux Ltd, manufacturer of air conditioners of the PIM, where the collection of data was made through desk research, interviews and questionnaires, molded based on the focus of the work and the guidelines established by ABNT NBR ISO 14040:2009, for the study of LCA. Secondly, the LCA methodology was applied, using software SimaPro 7.3 Faculty educational version, in order to identify the environmental impacts involved. The results obtained in the environmental assessment of the production process of window air-conditioning found that the electronic components, printed circuit boards and electrical components represent the greatest environmental burden in the production of these devices, due to the diversity of elements and compounds chemicals present in their compositions and the presence of toxic substances that cause harm to human health and the environment. The main potential impacts to which these inputs contribute are the carcinogenic effects, the use of fossil fuels and inorganic respiratory effects. Potential impacts include the categories of harm to human health, to ecosystem quality and to natural resources, the first being the most significant. The diagnosis of this evaluation made possible the construction of a benchmark survey for analysis and understanding of issues relating to the productive sector of air conditioning, contributing to the promotion of improvements in the product development and process, favoring cleaner production directed for sustainability. / A indústria de aparelhos de ar-condicionado é grande consumidora de matérias-primas e forte geradora de resíduos. O processo de produção e cada uma das etapas do ciclo de vida desses produtos acarretam impactos que contribuem para a degradação ambiental. O aparelho de ar-condicionado é um dos principais produtos manufaturados no Polo Industrial de Manaus e um dos mais vendidos no comércio local, devido às altas temperaturas, típicas da região. Diante disso, o presente trabalho avaliou os aspectos ambientais e impactos potenciais envolvidos no processo produtivo de aparelhos de ar-condicionado de janela, utilizando a ferramenta Avaliação do Ciclo de Vida (ACV). A ACV é uma técnica de gestão ambiental fundamentada na construção de inventário que considera as entradas de matérias-primas e energia, e as emissões de resíduos associadas ao processo produtivo. Nesse contexto, foi realizado um estudo de caso na Electrolux da Amazônia Ltda, empresa fabricante de condicionadores de ar do PIM, onde se fez o levantamento dos dados através de pesquisa documental, realização de entrevistas e aplicação de questionários, moldados com base no foco do trabalho e nas diretrizes estabelecidas pela ABNT NBR ISO 14040:2009, para o estudo da ACV. Num segundo momento, foi aplicada a metodologia de ACV, através da utilização do software SimaPro 7.3, versão educacional Faculty, com o objetivo de identificar os impactos ambientais envolvidos. Os resultados obtidos na avaliação ambiental do processo produtivo de aparelhos de ar-condicionado de janela constataram que os componentes eletrônicos, os painéis e circuitos impressos e os componentes elétricos representam a maior carga ambiental na produção desses aparelhos, em função da diversidade de elementos e compostos químicos presentes em suas composições e da presença de substâncias tóxicas que acarretam danos à saúde humana e ao meio ambiente. Os principais impactos potenciais, para os quais esses insumos contribuem, são os efeitos carcinogênicos, a utilização de combustíveis fósseis e os efeitos respiratórios inorgânicos. Os impactos potenciais abrangem as categorias de danos à saúde humana, à qualidade do ecossistema e aos recursos naturais, sendo o primeiro o mais expressivo. O diagnóstico dessa avaliação tornou possível a construção de um referencial de pesquisa para análise e compreensão de questões relativas ao setor produtivo de aparelhos de ar-condicionado, contribuindo para a promoção de melhorias no desenvolvimento do produto e do processo, favorecendo uma produção mais limpa direcionada para a sustentabilidade.
103

Externalidades do ciclo produtivo da cana-de-açúcar com ênfase na produção de energia elétrica / Externalities of sugarcane productive chain with enphasis in electrical power generation.

Thiago Guilherme Ferreira Prado 13 April 2007 (has links)
Este trabalho apresenta a avaliação das externalidades relativas ao ciclo produtivo da cana de açúcar, dando um enfoque para a questão da geração de energia elétrica. Os objetivos principais do estudo são realizar um levantamento uma análise das externalidades sociais, ambientais e econômicas do ciclo produtivo da cana-de-açúcar desde sua fase inicial (período agrícola) até a conversão energética da biomassa em energia elétrica (objeto de ênfase nesse projeto). Repartindo os impactos, quando possível nos subsistemas elaborados a partir da análise do ciclo produtivo do setor, cujos resultados de uma forma geral eram até então conhecidos, mas nunca segregados e tratados de forma integrada sob a ótica de avaliação das externalidades relacionadas à atividade de produção. A geração de eletricidade excedente traz consigo externalidades positivas e negativas. Elas envolvem aspectos prejudiciais sob a ótica das emissões atmosféricas sobre a saúde humana e o meio biótico; positivo, mediante a utilização de fontes renováveis para geração de eletricidade provendo o deslocamento de derivados do petróleo tanto para geração de energia térmica quanto de elétrica, reduzindo assim o consumo de combustíveis fósseis que são os principais componentes fomentadores da acentuação do efeito estufa; além dos benefícios associados à geração distribuída, discutidos neste trabalho. Ambas qualificam esta forma de geração dentro dos requisitos do mecanismo de desenvolvimento limpo, que será avaliado com a visão de ser um instrumento para internalizar o benefício de gerar energia com recursos renováveis. Dos impactos avaliados correspondentes ao ciclo produtivo da cana-de-açúcar, 32,68 % estão associados com a etapa de geração de eletricidade. Os principais impactos e efeitos avaliados na etapa qualitativa e quantitativa deste trabalho nas externalidades de produção foram ratificadas como efeitos predominantes também nas externalidades avaliadas via simulação computacional (ECOSENSE LE) do projeto ExternE. / This work presents the evaluation of externalidades in production from sugarcane life cycle, with emphasis at electric power generation. The main objective of this study is to assess the health, social, environmental and economical externalities related with the production process of sugarcane industry from the start point of the productive chain (agricultural period) until the energy conversion of the biomass in electric power (main emphasis). Distributing the impacts, when possible, in subsystems that main productive cycle were divided, whose results, in general, were known but never segregated and treated by an integrated view under the optics of externalities evaluation at the production activity chain at sugarcane sector. The surplus generation of electricity brings with itself positive and negative externalities. The negative ones involve harmful aspects under the atmospheric emissions and human health and the biotic environment; as positive ones, are the use of renewable sources for electricity generation providing displacement of fossil fuels and indirectly thermal and electrical energy, reducing the consumption of this kind of fuels that are the main promoting components from the accentuation of the greenhouse effect and the benefits associated to the distributed generation, also discussed in this work. Both of these positive aspects, qualify this form of generation to participate at the clean development mechanism, that it will be treated as an instrument for incorporate the benefit of generating energy with renewable resources. From the main productive chain impacts related to the life cycle of the sugarcane, 32,68 % are associated with the stage of electricity generation. The main impacts assessed in the qualitative and quantitative way as production externalities were confirm as predominant effects also using the computational simulation tool (ECOSENSE LE) from the ExternE project.
104

Kontorskyla : Kan borrhålskyla ersätta en kylmaskin?

Eriksson, Martin, Göräng, Mikael January 2013 (has links)
Syftet med rapporten är att göra en jämförelse av två olika metoder för att kyla ett fiktivt kontorshus som är 2 000 m² stort och beläget i Västerås. För att representera ett normalt kontorshus har kyleffektbehovet valts till 50 W/m² vilket ger totala kyleffektbehovet 100 kW. I ena fallet finns en kylmaskin som kyler byggnaden och i andra byts kylmaskinen mot ett antal borrhål som motsvarar hela kyleffekten. För att kunna bedöma de tekniker som har använts har energianvändning och växthuspotential beräknats i ett livscykelperspektiv. Denna energianvändning beräknas som inbäddad energi, vilket är all energi som använts från framtagande av råmaterialen till färdiginstallerat system. Växthuspotentialen beräknas i alla dessa steg som totala koldioxidekvivalenter. Ett sätt att bedöma den energibesparing som har gjorts är med en EROI-analys. EROI beräknas som sparad energi dividerat med investerad energi och är ett dimensionslöst tal som ger en indikation på hur värdefull investeringen är från energisynpunkt. Kylbehovet som finns i byggnader består av värmeöverskott, som uppkommer av bland annat belysning, datorer, kopiatorer och värme från människor. För att kyla bort denna värme finns ett antal olika kyltekniker. Kylmaskinen betraktas ofta som det klassiska sättet att skapa kyla, men är förknippad med en stor energianvändning under dess drift, främst till kompressor-drift. Till borrhålslösningen utgör en cirkulationspump enda elbehovet för att kunna skapa kyla, eftersom denna driftenergi är mycket lägre än för kylmaskinens kompressor ses ofta kyla från borrhål som gratis- eller frikyla. Byggnadens kylenergibehov har bedömts till 40 kWh/m2, år eller totalt 80 000 kWh/år. Detta kylenergibehov ger upphov till driftenergibehov. De årliga elbehoven beräknades till 26 145 kWh/år för kylmaskinen och 2 000 kWh/år för borrhålen. Dessa elbehov motsvarar de totala energierna 4 235 460 MJ för kylmaskinen samt 324 000 MJ för borrhålen under byggnadens livslängd. För att beräkna den inbäddade energin i dessa två lösningar krävdes livscykelanalyser. Det framkom snart att det inte fanns, av denna anledning användes byggvarudeklarationer för komponenterna. Till det hämtades livscykelanalyser för material. I de fall där det funnits varken livscykelanalyser eller byggvarudeklarationer har antaganden gjorts. Det som saknades var information om vad en kylmaskin innehåller, därför har det antagits att en värmepump och kylmedelkylare tillsammans kan fungera på samma sätt som en kylmaskin. Resultatet av beräkningarna för den inbäddade energin, tillverkning och transporter, beräknades till 74 627 MJ för kylmaskinen och 480 490 MJ för borrhålslösningen. Koldioxidutsläppen i samma skeden blev 4,8 ton koldioxidekvivalenter för kylmaskinen respektive 29,5 ton koldioxidekvivalenter för borrhålen. De stora skillnader som ses i inbäddad energi och koldioxidekvivalenter uppkommer av dieselanvändning, som krävs för att borra borrhålen. I denna rapport studeras scenariot att ersätta en kylmaskin som använts i fem år med ett antal borrhål, med samma kyleffekt, om detta kan vara fördelaktigt ur en energi- och miljömässig synpunkt. Studien visar att efter bara 4,5 år använder borrhålslösningen mindre energi, trots den höga inbäddade energin vid installationen. Den stora skillnaden består av elbehovet i driftskedet, där borrhålen har en cirkulationspump som använder betydligt mindre el än kylmaskinens kompressor. Den andra kategorin som har undersökts i denna studie har varit växthuspotential i form av koldioxidekvivalenter, som uppkommer under hela livstiden för båda lösningarna. Ett av kylmaskinens utsläpp kommer från köldmediet (R407C), ett kg köldmedie motsvarar 1 526 kg koldioxidekvivalenter. Det antogs att 4 % av detta köldmedie årligen läcker till omgivningen under alla år 45 år, detta läckage gav en total växthusverkan på 46,6 ton koldioxidekvivalenter. Det förekommer även stora koldioxidutsläpp i driftskedet, eftersom elbehoven är totalt 1 177 MWh för kylmaskinen och 90 MWh för borrhålen. En litteraturstudie visade att koldioxid-utsläppen vid produktion av el varierar mycket beroende på vilka förhållanden som råder, utsläppen varierar från 0 till 1 269 kg/MWh. Det visade sig dock att borrhålets koldioxid-utsläpp är lägre än kylmaskinens även vid låga koldioxidemissioner från elproduktion. Detta beror på läckaget av köldmedie som förekommer i kylmaskinen. Resultaten visar att oavsett utsläpp från elproduktion kommer borrhålen ha en lägre växthuspotential än kylmaskinen. Om kylmaskinen skulle användas under byggnadens livslängd skulle den ha en viss inbäddad energi och om borrhålen användes under byggnadens livslängd skulle de ha en annan inbäddad energi. Skillnaden i dessa energier kallas sparad energi. Investerad energi beräknas som den energi som krävs för att ersätta kylmaskinen med borrhålen. Med sparad och investerad energi kan först nettoenergin beräknas som skillnaden mellan dessa, den blev 3 089 025 MJ. EROI beräknas sedan som kvoten av sparad och investerad energi och blev 7,4, vilket innebär att ett byte av en befintlig kylmaskin till en borrhålslösning är fördelaktig ur energisynpunkt. / The purpose of this study is to compare cooling from a refrigeration machine and a borehole system. These technologies are chosen because they are observed as each other’s opposites. A refrigeration machine is associated with a requirement of large amounts of electric energy, while the borehole system is often seen as free cooling. The study is performed on a fictional building located in Västerås. The building has an area of 2 000 m² and a cooling requirement of 50 W/m². In the scenario studied the building is already equipped with a refrigeration machine, the goal is to examine if it can be motivated to remove this machine and replace it with a borehole system. The chosen environmental impact categories are embodied energy and carbon dioxide equivalents. In order to evaluate the embodied energy, EROI (Energy return on investment) is used to calculate the energy saved by removing the refrigeration machine. For the refrigeration machine most of the energy used is during the operation phase, this is because of the compressor which is used to produce cooling energy. In the borehole system 40 % of the energy used is during the operation phase and 60 % during the manufacturing phase. The drilling used 8.1 m3 diesel fuel, which dominated both the embodied energy and the carbon dioxide emissions of the borehole system. Results show that after only 4.5 years after installation the borehole system has less total embodied energy. EROI was then calculated as saved energy divided by invested energy and the result was an EROI of 7.4. The carbon dioxide emissions from both systems are heavily dependent on the CO2-emissions from electricity generation. Though, if a refrigeration machine were used during the buildings entire lifetime the leakage of refrigerant would be big enough to counteract this dependence.
105

Development of a calculator for estimation and management of GHG emissions from public transit agency operations

Weigel, Brent Anthony 08 July 2010 (has links)
As managers of extensive vehicle fleets and transportation infrastructures, public transit agencies present unique opportunities for reducing greenhouse gas (GHG) emissions from the transportation sector. To achieve substantial and cost-effective GHG emissions reductions from their activities, public transit agencies need tools and resources that enable effective GHG emissions management. This research thesis presents the background, methodology, and results of the author's development of a public transit agency-level life cycle GHG emissions calculator. The development of the calculator involved a series of research efforts aimed at identifying and addressing the needs of transit agency GHG emissions management: a review of background information on climate change and public transit's role in mitigating climate change; a review of existing GHG emissions calculators for public transit agencies, a review of the methodologies for life cycle GHG emissions analysis; integration and adaption of existing calculation resources; development of calculator spreadsheets for estimating relevant lifecycle GHG emissions and quantifying GHG emission reduction cost-effectiveness; application of the developed calculator to a carbon footprint analysis for a typical mid-size to large-size transit agency; and application of the developed calculator to the evaluation of the cost-effectiveness of various potential strategies for reducing transit agency GHG emissions. The developed calculator provides an integrative resource for quantifying GHG emissions and costs of public transit agency activities, including GHG emission reduction strategies. Further research is needed to calibrate the estimation of upstream life cycle GHG emissions, particularly for vehicle manufacture and maintenance.
106

Framtagning av ekodesignat produktförslag för Ekdahls möbler / Development of an eco-designed product suggestions for Ekdahls möbler

Eriksson, Gabriella, Zachau, Sandra January 2015 (has links)
En balans mellan hållbar utveckling, klassisk design och unikitet kan bidra till att minska dagens konsumtion. Begreppet ekodesign innefattar en produkts miljöpåverkan genom dess livscykel utan att äventyra med andra komponenter som kvalité, kostnad och formgivning. Att skapa en innovativ ekodesignad produkt utan att kompromissa skapar en hög attraktionsnivå och gör det enklare för kund att välja rätt, vilket medför ett högt kundvärde där produkten får leva genom generationer. Syftet med studien var att ta fram ett unikt ekodesignat produktförslag för uppdragsgivaren Ekdahls möbler som skall kunna brukas och uppskattas genom flera generationer där följande frågeställningar besvarats; [1] Vilka gemensamma framgångsfaktorer utgör en klassiskt designad sittmöbel? [2] Hur kan man utveckla en unik ekodesignad sittmöbel? För att besvara studiens första frågeställning genomfördes en dokumentundersökning som följts av en sambandsmatris för att konstatera de gemensamma framgångsfaktorerna hos klassiskt designade stolar. En intervju genomfördes för att analysera och stärka framgångsfaktorerna. Arbetet resulterade i att följande framgångsfaktorer var avgörande för en klassisk designad sittmöbel; unik, komfortabel, kvalitativ, estetisk, kreativ och användarvänlig vilka utgjorde formspråket på det slutliga produktförslaget. För att besvara studiens andra frågeställning tillämpades en designprocess där integrering av verktyg för ekodesign i form av statusanalys, kravspecifikation, funktion- och livscykelanalys samt ekostrategihjulet skapade ett miljöarbete samt en skräddarsydd och mer anpassad process för framtagningen av studiens produktförslag. Genom att följa designprocessens alla steg grundligt med komplettering av integrerade verktyg för ekodesign skapades inte bara en unik utvecklingsprocess utan även ett unikt projekt mot en ekodesignad produkt. Unikiteten är den framgångsfaktorn som värderades högst. Genom att leva upp till den samt de andra framgångsfaktorerna i det slutliga produktförslaget skapades en möjlighet att bli eftersträvansvärd på marknaden och på så sätt även öka livslängden för produkten.Produkten utstrålar klassisk och säregen design där kärleken för naturmaterial och kvalité står i centrum. Genom dess optimering i synpunkt på miljöpåverkan och dess unika formspråk är det en produkt att stolt leva med genom flera generationer. / A balance between sustainable development, classic design and uniqueness can help to reduce today’s consumption. The concept of eco-design includes a product's environmental impact throughout its life cycle without compromising with other components such as quality, cost and design. Creating an innovative eco-designed product without compromising makes it highly attractive and easier for the customer to choose the right product resulting in high customer value where it will live through generations. The purpose of the study was to develop a unique eco-designed product suggestion, for the client Ekdahls möbler, that will be used and appreciated by many generations in which the following questions were answered; [1] What common factors of success represent classically designed seating furniture? [2] How can a unique eco-designed seating furniture be developed? To answer the first question of the study a document investigation followed by a connection matrix was done to determine common success factors of classically designed chairs. An interview was conducted to analyze and strengthen the success factors. The result showed that the following success factors were crucial for a classically designed seating furniture; unique, comfortable, qualitative, aesthetic, creative and user friendly which constitute the design language of the final product proposal. To answer the second question of the study a design process was applied in which the integration of eco-design tools in the form of status analysis, requirements specification, functional and lifecycle analysis and the eco strategy wheel created an environmental and tailored process for the development of the study’s product proposals.' By following the design process’s every step thoroughly with supplementation of integrated tools for eco-design not only a unique development process was created, but also a unique project towards an eco-designed product. Uniqueness is the success factor valued most. By living up to it as well as the other factors for success in the final product proposal, an opportunity to become desirable in the market was created and thus also increase the longevity of the product.The product radiates classic and distinctive design where the love for natural materials and quality are central. Through its optimization of environmental impact and its unique design language it is a product to proudly live with through several generations.
107

Life cycle analysis of sediment control devices

Troxel, Cameron Francis 20 September 2013 (has links)
Sediment control devices (SCDs) are critical to reducing the contamination of waterways from adjacent construction sites. Perimeter sediment controls retard the flow of surface runoff water originating on site and subsequently reduce solid, nutrient, and metal concentrations suspended in the flowing water. Silt fence is a commonly used SCD comprised of geotextile filter fabric, steel or wood support posts, and wire mesh reinforcement. The Georgia Department of Transportation (GDOT) uses an extensive amount of silt fence every year, and because of high degradation of geotextile in the field, the silt fence installations are rarely recycled. This research measures the performance of five SCDs (two types of silt fence, mulch berm, compost sock, and straw bales) at suspended solid, turbidity, nutrient, and metal reduction. A life cycle analysis (LCA) is performed to identify environmental impacts associated with material production, assembly, installation, use on site, and disposal. An impact analysis is performed according to for each SCD. Results of the impact analysis are compared to determine the SCD with lowest overall environmental impact. Results of the SCD performance study show that silt fence installations performed the best at reducing suspended solids and turbidity, mulch was best at reducing nutrients, and compost was the best at reducing metal concentrations. The life cycle impact analysis indicates that a mulch berm is the SCD with the lowest overall environmental impact. The impact analysis included global warming potential, acidification, eutrophication, and aquatic toxicity.
108

Couplage entre les régions IIS4-S5 et IIS6 lors de l’activation du canal calcique CaV2.3

Wall-Lacelle, Sébastien 12 1900 (has links)
Les canaux calciques dépendants du voltage CaV font partie de la famille structurale des canaux ioniques à 6 segments transmembranaires. Tout comme les canaux potassiques Kv, les canaux CaV possèdent une série de résidus chargés dans l’hélice S4 de chaque domaine ou sous-unité qui conférerait à la protéine une sensibilité aux changements de voltage. De plus les hélices S6 tapissent la paroi du pore et forment la porte d’activation de la protéine. Comment le mouvement des hélices S4 se traduit par l’ouverture de la porte d’activation des hélices S6 demeure une question encore non résolue. Suite à la publication de la structure cristalline du canal Kv1.2 en 2005, le groupe de MacKinnon a proposé que le mouvement des hélices S4 est mécaniquement couplé à la porte d’activation S6 à travers le glissement de l’hélice amphiphile S4-S5 selon un mécanisme nommé couplage électromécanique (Long et al. 2005b). Dans le but de déterminer si la région S4-S5 joue un rôle dans l’activation du canal calcique CaV2.3, nous avons étudié, par la méthode d’analyse cyclique de mutations doubles (« Double Mutant Cycle Analysis », (Horovitz 1996)), le couplage entre la boucle S4-S5 et l’hélice S6 du domaine II de ce canal. Les mesures d’énergies d’activation, ΔGact, obtenues en présence des sous-unités auxiliaires CaVα2δ et CaVβ3 ont affiché un couplage significatif pour l’activation entre les paires de résidus V593G/L699G, V593G/A700G, V593G/A702G, S595G/V703G L596G/L699G, L596G/A700G, L596G/I701G, L596G/A702G, L596G/V703G, L596G/D704G, M597G/I701G, et S602G/I701G. Aucune de ces paires de résidus n’a affiché de couplage lors de l’inactivation, suggérant que les effets observés sont spécifiques au mécanisme d’activation. Mis ensemble, ces résultats suggèrent que la boucle IIS4-S5 et l’hélice IIS6 interagissent et jouent un rôle déterminant dans l’activation de CaV2.3. / Voltage dependent calcium channels share a strong structural homology with voltage gated potassium channels. Both families present a conserved series of charged residues present in the S4 helix of each domain that most certainly accounts for the voltage sensitivity of these proteins. Moreover, in both cases, the S6 helices seem to be lining up the pore. How does the movement of the S4 sensors translate into channel opening remains elusive in Ca2+ channels. Following the publication of the crystal structure of the Kv1.2 channel in 2005, the group of Roderick MacKinnon proposed that the voltage sensor is mechanically coupled to the S6 pore through the amphipathic S4-S5 helix that crosses over the S6 inner helix from the same subunit. To determine if the S4-S5 linker, that runs parallel to the membrane plane inside the cell in the Kv1.2 three-D structure, plays a role in the activation of the CaV2.3 calcium channel, we have studied by double mutant cycle analysis the coupling between the S4-S5 linker and the S6 helix of domain II of this channel. The activation energies, Gact, obtained from classical two electrode voltage clamp experiments in the presence of auxiliary subunits CaV2 and CaV3 displayed significant activation coupling coefficients for the pairs of residues V593G/L699G, V593G/A700G, V593G/A702G, S595G/V703G L596G/L699G, L596G/A700G, L596G/I701G, L596G/A702G, L596G/V703G, L596G/D704G, M597G/I701G, and S602G/I701G. None of these pairs displayed significant coupling in the inactivation mechanism, suggesting that the effects observed were specific to activation. Altogether, our results strongly suggest that the S4-S5 linker and the S6 helix of domain II are actively involved in the activation of CaV2.3.
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Daugiabučio namo aprūpinimo energija technologinių sprendinių daugiakriterė analizė / Multi-criteria analysis of energy supply technological solutions

Matuzas, Martynas 18 June 2013 (has links)
Baigiamajame magistro darbe nagrinėjamas tipinis daugiabutis pastatas ir jam pritaikytos energiją generuojančios sistemos. Darbo tikslas – daugiakriterio vertinimo metodu nustatyti optimalų energijos aprūpinimo technologinį sprendinį pagal energinį, ekologinį ir ekonominį kriterijus. Tyrime nagrinėjama centralizuoto šilumos tiekimo sistema, dujinis katilas, oras–vanduo ir gruntas–vanduo šilumos siurbliai, saulės kolektoriai, saulės elementų bei visų šių sistemų kombinacijos. Tyrimui naudojami realūs šilumos suvartojimai ir statistiniais metodais nustatyti elektros energijos poreikiai. Sistemos nagrinėjamos modeliuojant EnergyPRO programa. Visoms sistemoms atlikta inventorinė analizė, nustatyti sunaudojamos energijos ir išsiskiriančių teršalų kiekiai visų sistemų gyvavimo fazių metu. Atlikus sistemų modeliavimą ir kitus tyrimus paaiškėjo, kad optimali yra kombinuota sistema susidedanti iš gruntas-vanduo šilumos siurblio, saulės kolektorių, saulės elementų ir centralizuoto šilumos tiekimo. Tokios sistemos šilumos savikaina yra 18,7 ct/kWh, teršalų emisija – 0,131 CO2 kg ekv/kWh/100 metų, pirminės energijos poreikis – 2,50 MJ/kWh/100 metų. Tokia sistema padengia beveik 85 % pastato metinio šilumos poreikio. Tyrimo rezultatai gali būti pritaikyti daugiabučių namų renovacijai. Darbą sudaro 14 skyrių. Darbo apimtis 65 p. teksto be priedų, 38 iliustr., 22 lentelių 36 bibliografinių šaltinių, priedai (pridedami kartu). / In this thesis a typical apartment building and its own energy generating systems were examined. The goal of this work – to determine the optimum power supply technology solution for energy supply, using multi-criteria analysis according to several criteria: energetical, environmental and economical. The study examined the district heating system, gas boiler, air-to-water and ground-water heat pumps, solar collectors, solar cells, and the combination of these systems. The study uses real heat consumption and statistical methods to determine power requirements. Systems were analyzed using EnergyPRO simulation program. For all systems were performed inventory analysis, to determine the energy consumption and the quantity of emissions of all the systems life phases. After system modeling and other studies results showed, that the optimum system is combined system of the ground-to-water heat pump, solar panels, solar cells, and district heating cost – 18.7 ct/kWh; Emission of pollutants – 0,131 CO2 eq kg/kWh/100 years; Primary energy demand – 2.50 MJ/kWh/100 years. Such a system covers nearly 85% of the building's annual heat demand. The results can be applied to residential buildings projects of renovation. The work consists of 14 chapters. Scope of work 65. text, 38 figures., 22 tables of 36 bibliographic entries, (added together).
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Hållbart byggande : Hur nyproduktion i trä och betong i Sverige påverkar miljön samt beslutsfattares beslutsgrunder gällande materialanvändning

Johansson, Stina January 2018 (has links)
Environmental changes are great challenges that humanity must face. This has spurred a flurry of activities aimed to lower our impact on our environment. This essay focuses on the aspects that influence decision makers when choosing construction materials as well as a look into whether wood has a lower impact on the environment compared to concrete when building houses. The materials have been assembled through surveys, interviews and literary studies. The primary factor that was given most weight among entrepreneurs and architects were robustness and safety, and concrete was in that regard favoured over wood. It is also possible that already established economical structures support the use of concrete instead of wood. Environmental aspects are not reflected among entrepreneurs as very important factors when it comes to choosing materials and for change to occur there needs to be more information supporting that wood can be as robust as concrete in structures for it to be similarly prioritised. Concerning wood’s impact on the climate and the environment compared to concrete there is a significant difference in woods favour if only the construction and production phase of the house’s life cycle is examined. However, there are studies that show that depending on the material used and the time the house is expected to remain there are instances where wood has a higher environmental impact than concrete. Conclusively, wood is not always more environmentally friendly. The environmental impact of a material in construction depends heavily on the life span of the house.

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