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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.
41

Värmetröghet i byggnader : En studie som undersöker en skolbyggnad utifrån olika materials värmetröghet samt dess klimatpåverkan genom en livscykelanalys

Axelsson, Kerstin January 2022 (has links)
Thermal inertia is defined as “a measure of the responsiveness of a material to variations in temperature”. This means that materials with high thermal inertia will show small changes in temperature during a cycle of time and vice versa. This study aimed to evaluate the energy saving potential of thermal inertia which can be raised by the choice of various building materials. For this aim, a case study of a preschool building was used in which different configurations (i.e. different combinations of materials) of exterior walls and interior floors were studied using a building energy simulation program, IDA Indoor Climate and Energy (IDA ICE). The study mainly focused on the materials and configurations that yielded high thermal inertia where the results were compared with the as- built design of the preschool building in terms of heating and cooling demand as well as overheating. Furthermore, a life cycle analysis (LCA) was conducted using a LCA program, i.e. One Click LCA. This was done in order to understand better how the choice of building materials, besides the thermal inertia and its energy-saving potential, could affect the carbon footprint of a building from a life cycle perspective. The results indicated that there aren't significant differences in heating demand between the studied material configurations and the reference building. However, moderate changes were observed in both cooling demand and overheating, especially for some materials that have higher thermal inertia. A common denominator among these configurations was that all consisted of interior floors of either wood or massive wood. However, in terms of ”CO2 emissions”, significant differences between the studied materials and reference building were observed. In general, it was found that the life carbon impact increased in the most material configurations. This increase was more than offsetting reductions obtained in the operational ”CO2 emissions”, i.e., the reduction in energy demand caused using materials with higher thermal inertia. The configurations that performed better than the reference building from a life cycle perspective were the ones that didn’t consist of concrete, neither for exterior walls or interior floors.
42

Ökologische Bewertung von zentralen und dezentralen Abwasserentsorgungssystemen

Schubert, Rebecca 09 May 2014 (has links) (PDF)
Die zentralen Abwasserentsorgungssysteme sind aufgrund der langen Nutzungsdauern und der Leistungsgebundenheit unflexibel gegenüber sich ändernden Rahmenbedingungen, wie dem demografischen Wandel, dem Klimawandel und einem sinkenden Trinkwasserverbrauch. Kleinkläranlagen werden daher häufig als eine Alternative diskutiert, vor allem wenn es um die Erschließung von neuen dezentral gelegenen Grundstücken geht, da eventuell höhere Kosten für das neue Kanalnetz zur zentralen Kläranlage anfallen. Um sich für eine der beiden Möglichkeiten zu entscheiden, werden bisher vorrangig ökonomische Instrumente eingesetzt. Ökologische Bewertungsmethoden finden bislang als Entscheidungsinstrument noch keine Anwendung. In dieser Arbeit wird exemplarisch eine Ökobilanzierung durchgeführt. Sie kann jedoch nur dann zur Entscheidungsfindung genutzt werden, wenn die Ergebnisse auch robust und zuverlässig sind. Deshalb ist es notwendig mit möglichen Unsicherheiten in der Ökobilanzierung offensiv umzugehen. Aus diesen Problematiken ergibt sich das zentrale Forschungsinteresse der ökologischen Bewertung von dezentralen Abwasserentsorgungssystemen im Vergleich zu zentralen Systemen. Dabei fließen die Abhängigkeit der Länge des Kanalnetzes und die Anzahl der angeschlossenen Einwohner, unter besonderer Berücksichtigung von Datenunsicherheiten bei der Ökobilanzierung, ein. Es wird die Methode der Ökobilanzierung angewendet, welche sich nach DIN EN ISO 14040 (2009) und DIN EN ISO 14044 (2006) richtet. Die Literaturrecherche ergibt, dass wenig Literatur über Kleinkläranlagen zur Erstellung einer Ökobilanz zur Verfügung steht. Deshalb wird ein Fragebogen an Hersteller von Kleinkläranlagen versendet. Auf Grundlage der erhobenen Daten wird eine Ökobilanz für eine SBR-Anlage und eine Rotationstauchkörperanlage erstellt. Um die Breite der Daten zu erfassen, wird die Szenarioanalyse verwendet. Dagegen stammen die Daten für die zentrale Anlage aus der EcoIvent-Datenbank für die Abwasserentsorgung (DOKA, G. (2007)), wofür weitere Szenarien erstellt werden. Die funktionelle Einheit sind vier Einwohnerwerte. Nach Aufstellung der Sachbilanz, wird die Methode „CML 2 baseline 2000“ zur Wirkungsabschätzung in SimaPro 7.1 eingesetzt. Mit einer Break-Even-Analyse werden die Abhängigkeiten von der Länge des Kanalnetzes und der angeschlossenen Einwohner für die Abwasserentsorgungssysteme untersucht. Die Integration der Datenunsicherheit erfolgt mittels einer Sensitivitäts- und einer Monte Carlo-Analyse. Die Analysen ergeben, dass sich die Installation einer Kleinkläranlage eher lohnt, wenn die kommunale Kläranlage weiter vom Haushalt entfernt und die Anzahl der angeschlossenen Einwohner gering ist. Eine SBR-Anlage ist einer Rotationstauchkörperanlage vorzuziehen. Die verwendeten Methoden zum Umgang mit Unsicherheiten zeigen, dass sich Ökobilanzen als Entscheidungsinstrument eignen. Die Anwendung von Methoden zur Vermeidung bzw. Eingliederung von Unsicherheiten muss noch viel stärker in die Ökobilanzen von Abwasserentsorgungssystemen einfließen. / Next to municipal sewage treatment plants for sewage treatment, decentralized small wastewater treatment plants can be applied. Given a long working life and a dependence on user numbers, central sewage systems are inflexible in respect to overall conditions such as demography, climate or declining water consumption. Small wastewater treatment plants in rural areas can be an alternative, especially in the case of new plots for buildings because of new expensive sewer grids. Economic methodologies help to choose one of these facilities whereas ecological assessments are neglected. This thesis focuses a life cycle assessment (LCA), but this can only been used if the results are robust and reliable. Hence it is necessary to analyze uncertainty factors of life cycle assessments. The following main objective arises: The ecological assessment of small wastewater treatment plants in comparison to a municipal sewage treatment plant as a function of the length of sewer grid and the number of connected inhabitants to the central sewer system in consideration of dealing with data uncertainty of LCA. A simplified LCA study, which is based on the DIN EN ISO 14040 (2006) and the DIN EN ISO 14044 (2006), is applied to capture this objective, which means in detail the analysis of environmental effects during the production, operation, and disposal phase. As the literature review has shown, available data on small wastewater treatment plants is nearly non-existent. Hence, conducting a survey among the producers of small wastewater treatment plants completes the less available literature. Based on the questionnaire-data, a LCA for of sequencing batch reactor (SBR) plant and rotating biological contactor plant is applied. The scenario analysis captures the extensive amount of the available data adequately. In contrast, the data for the central sewage treatment plant comes from the EcoInvent-Database for Wastewater Treatment (DOKA, G. (2007)) and is further used for other scenarios. The functional unit consists of four population equivalents. After collecting all data for the Life Cycle Inventory Analysis, the estimation of effectiveness is done by applying the “CML 2 baseline 2000” method implemented in SimaPro 7. By means of Break-Even-Analysis the dependence on the length of sewer grid and the number of inhabitants connected to the sewer grid is analyzed. To explicitly incorporate the uncertainty in LCA the Sensitivity analysis and the Monte Carlo-Analysis is used. The most important result is that the higher the distance between the household and the central sewage treatment plant and the lower the number of connected inhabitance, the more preferable is the small wastewater treatment plant. Furthermore, SBRs are generally preferred in comparison to rotating biological contactor plants. Concerning the treatment of uncertainty factors, the analysis of different methods confirms the LCA as the most accurate variant. Further requirements of research are in respect to prevent uncertainty factors or integrate them in LCAs of sewerage systems.
43

Integrering av ekosystemtjänsbegreppet i LCA-metodik : Kartläggning av möjligheter genom en fallstudie på pelletsproduktion / Integrating the Ecosystem-Service Concept into LCA-methodology : Mapping of possibilities through a case study on pellet production

Nordin, Emma January 2014 (has links)
De nyttor som människan får direkt och indirekt från ekosystemen kallas ekosystemtjänster. Mänsklighetens påverkan på ekosystemen idag leder till degradering av tjänsterna och då mänskligheten ytterst är beroende av vad de tillför, är bevarandet av dessa tjänster viktig. Livscykelanalys, LCA, är ett väletablerat verktyg som används för att fastställa miljöpåverkan från olika produktprocesser men få ekosystemtjänster beaktas i LCA. Det finns därför ett behov av att vidare undersöka och utveckla möjligheterna att med livscykelbaserade metoder analysera påverkan på ekosystemtjänster. Huvudsyftet med denna studie har varit att undersöka om det är möjligt att integrera ekosystemtjänstbegreppet i LCA-metodik. Detta har kartlagts med hjälp av en fallstudie på pelletsproduktion, som bl.a. identifierat berörda ekosystemtjänster och möjligheten att kvantifiera dem, vilka ekosystemtjänster som går att studera med LCA idag samt möjliga sätt att analysera påverkan på ekosystemtjänster med LCA. Ett delmål har varit att grundligt beskriva både ekosystemtjänster och LCA samt aspekter som kan koppla ihop dessa områden. En omfattande litteraturstudie och en LCA modellering rörande pelletsproduktion utgjorde grund för arbetet. I dagsläget är det inte möjligt att integrera ekosystemtjänstbegreppet i LCA-metodiken med undantag för de fåtal ekosystemtjänster som i LCA-metodiken redan beaktas i viss utsträckning. Det stora hindret är att det inte finns någon fullständig och enhetlig metodik för kartläggning, klassificering och kvantifiering av ekosystemtjänsterna, vilket anses nödvändigt för att kunna analysera påverkan på dem. Ett stort antal ekosystemtjänster såsom klimatreglering, näringsflöden, biodiversitet och rekreation kan kopplas till pelletsproduktion men påverkan på dem är inte möjlig att fullt ut analysera med LCA. Detta illustreras av LCA-modelleringen av pelletsproduktion där endast påverkan på tjänsterna förnybara energikällor och vattenanvändning ingår. Då kunskapen rörande olika ekosystemtjänster skiljer sig mycket åt varierar förutsättningarna för att inkludera dem i LCA-metodiken. Befintliga tillvägagångssätt för att försöka analysera påverkan på ekosystemtjänster med hjälp av LCA föreslår nya miljöpåverkanskategorier och samlandet av tjänsterna i gemensamma enheter såsom exergi och solekvivalenter. Metoderna är dock begränsade och täcker inte in ekosystemtjänsterna på ett fullgott sätt. Mer forskning behövs för att bättre utveckla tillvägagångsätten för analys av påverkan på ekosystemtjänster genom LCA. / The profits humankind obtains directly and indirectly from ecosystems are called ecosystem services. The impact human activities have on ecosystems lead to degradation of the ecosystem services and since humankind fully depends on what the ecosystems provide, the preservation of these services is crucial. Lifecycle assessment, LCA, is a well-established tool used to assess environmental impacts from different product processes but few ecosystem services are considered. Thus, there is a need to study and develop the possibilities to analyze ecosystem services through LCA based methods. The project aimed to determine whether it is possible to integrate the ecosystem-service concept into LCA-methodology. A case study on pellet production was carried out to identify relevant ecosystem services and the possibilities to quantify them, which ecosystem services that could be analyzed in LCA today and also available approaches to study impacts on ecosystem services with LCA. An intermediate goal was to present a comprehensive description of both ecosystem services and LCA and to map common aspects that connect the two fields. The analysis was based on a comprehensive literature study, and a specific LCA-modeling of pellet production. At present, it is not possible to integrate the ecosystem-service concept into LCA-methodology, except for the few ecosystem services that to some extent already are covered in the methodology. The main obstacle is the lack of coherent approaches to map, classify, and foremost quantify ecosystem services, which is considered crucial for analyzing the impact on them. A large number of ecosystem services such as climate regulation, nutrient cycling, biodiversity and recreation can be influenced by pellet production but it is not possible to fully analyze these impacts with LCA. This is illustrated by the LCA-modeling on pellet production where only impacts on the services renewable resources and water use could be included. The possibilities to analyze ecosystem services within LCA vary due to the variation in knowledge about certain services. The present approaches for analyzing more services with LCA propose new environmental impact categories an aggregation of services into common units such as exergy and solar equivalents. The methods are limited due to the fact that they are not able to cover the diversity of the services. More research is needed to develop the approaches for analyzing impacts on ecosystem services through LCA.
44

Hur påverkas miljön av limträ- eller stålstomme för en lantbruksbyggnad?

Eliassi, Kamal January 2016 (has links)
Global climate change is one of the most important tasks that scientists are trying to solve today. With the help of a Lifecycle Analysis (LCA) method, the impact that many materials and services have on the environment and humans, have been determined.  As a task given by Gävleborg County Administrative Board, this work examines which of the material, glulam or steel, is most suitable as load-bearing material for agricultural buildings (barns). The goal of this study is to perform a LCA (Life Cycle Assessment) of the two materials during production, use, transportation and reuse. The steel's advantage is to be reused again without losing its properties and the wood's benefits to be used as an energy source during combustion, is only one of the steps involved in a life cycle analysis.  The information that an LCA study requires can be infinite and complex and therefore needs limitations in resources and time. A system boundary makes a basis on which phases and influences are the vital parts of a study. The system boundary also includes geographical areas. The study examines only local agricultural buildings in Gävleborg, Sweden, with floor areas of approximately 1300 m2 and their global environmental impact.  Environmental impact of a product is usually allocated in several different environmental impact categories, in which the study examines only three of these: global warming, acidification and eutrophication.  The results show a great difference in emissions depending on how the materials are produced and how they are handled after use. It proves that glulam has significant fewer emissions than steel when it used as an energy source instead of being deposited. With help of the weighting method the result show that iron ore produced steel have 1.2 times greater emission then glulam with landfill and 5.2 times greater when it is used in energy recovery. The weight also shows that scrap produced steel have 0.5 less emission than glulam with landfill and 2.4 greater than glulam with energy recovery. / Problematiken kring den globala klimatförändringen är ett av de problem som forskare försöker lösa idag. Med hjälp av metoden livscykelanalys har många material och tjänster utretts gällande dessas påverkan på miljön och människan. På uppdrag från Länsstyrelsen Gävleborg granskas vilket av materialen, trä eller stål, som är lämpligast som stomme i stallbyggnader ur miljösynpunkt. Målet med denna studie är att utföra en LCA (livscykelanalys) av de två materialen vid produktion, användning, transport och återanvändning. Stålets möjligtvis största fördel innebär att det kan återanvändas om och om igen utan att förlora sina egenskaper och trädets möjligheter till återvinning som energi vid förbränning är endast två av de stegen som ingår i en livscykelanalys. Informationen som en LCA studie består av kan vara oändlig och komplex och kräver därför tydliga avgränsningar gällande resurs och tid. En bestämd systemgräns utgör därför ett underlag på vilka faser och påverkningar som är vitala delar för undersökningen. Systemgränsen innefattar också vilka geografiska områden som undersöks. Studien granskar därför lokala lantbruksbyggnader i Gävleborg med golvarea på cirka 1300 m2 och deras globala miljöpåverkan. Olika typer av miljöpåverkan som uppstår från en produkt kategoriseras i miljöeffektkategorier där studien undersöker tre av dessa: den globala uppvärmning, försurning och övergödning. Resultatet visar en stor skillnad i utsläpp beroende på hur materialen producerats och även hur de hanteras efter användning. Det visar sig att limträ har betydligt mindre utsläpp än stål om den kan energiåtervinnas. Med hjälp av viktningsmetoden visar det sig att järnmalm släpper ut 1,2 gånger mer utsläpp från de sammanlagda miljöeffektkategorierna än limträ som deponeras och 5,2 gånger mer om den energiutvinns. Vid viktningen av skrot blir utsläppet 0,5 gånger mindre än limträ med deponi och 2,4 mer än limträ med energiutvinning.
45

Vliv ruptury a plastiky předního zkříženého vazu na posturální stabilizaci jedince / Influence of a rupture and reconstruction of an anterior cruciate ligament on the postural activity of an individual

Mináriková, Jitka January 2013 (has links)
Name: Influence of a rupture and reconstruction of an anterior cruciate ligament on the postural activity of an individual Aim: The aim of my thesis is to find out whether a rupture and the following rupture recinstruction of an anterior cruciate ligament has an influence on the postural activity of an individual namely after a longer period ( at least one year) from the undergone operation. Methods: The thesis has been worked out by a form of an analytical comparative study where it deals with measuring of two groups of probands - healthy and those after anterior cruciate ligament operation. The postural behaviour of individuals was tested after deflection by impact of a pendulum at a free standing position with and without visual control and also when standing on one leg. Results: The results of the measuring denote that when a person after anterior cruciate ligament rupture and following rupture recinstruction is deflected by an external impact while standing on both legs he/she will rather rely on the leg without surgery but the side difference will not be very distinctive. This fact will not change much even without visual control. While standing on one leg though the individual after surgery will have a more serious problem to stabilize his/her position (the period of time to stabilize will...
46

Análise da fundamentação da avaliação do ciclo de vida consequencial. / Analysis of the fundamentals for consequential life cycle assessment.

Muniz, Vivian Carolina Ferreira 01 June 2012 (has links)
O presente trabalho apresenta o resultado da análise sobre o novo foco da ferramenta Avaliação do Ciclo de Vida (ACV): a ACV consequencial. O método convencional da ACV - ACV atribucional - tem sido criticado pelo fato de não suportar decisões baseadas em cenários futuros. Como resposta a esta deficiência, a ACV consequencial surge como uma proposta a um método mais apropriado que avalia consequências ambientais futuras provocadas pelo uso do produto em estudo. O enfoque consequencial apresenta uma abordagem nova da ACV; ainda existem visões distintas e, algumas vezes, divergentes desta abordagem na comunidade internacional da ACV, seja na área acadêmica, seja fora dela. Neste trabalho são apresentadas e discutidas as diferenças, limitações, vantagens e desvantagens entre essas duas ferramentas. Foi possível observar que na realização de um estudo de ACV de um produto ou serviço, a definição do objetivo e escopo do estudo é fundamental para a escolha de qual enfoque da ACV será aplicado. Observou-se, também, que há limitações metodológicas tanto para a ACV atribucional como para a ACV consequencial. No caso da ACV atribucional, por exemplo, há incertezas com relação à escolha subjetiva do método de alocação de co-produtos. Já no caso da ACV consequencial, os resultados podem ser mais sensíveis e mais suscetíveis a incertezas devido às inclusões de estudo da tendência e projeções do mercado para a escolha dos dados e tecnologias marginais, e para a previsão de dados. / The main purpose of this master is to present the analysis results on the Life Cycle Assessment (LCA) new approach: consequential LCA. The conventional method of LCA the attributional approach - has been criticized for not supporting decisions based on future scenarios. In response to this deficiency, the consequential LCA appears as a proposal to a more appropriate method to evaluate future environmental consequences caused by the use of the product under study. As the consequential LCA represents a new approach to LCA, there still are divergent opinions within the LCA international community. In this work, there are shown and discussed the main differences, limitations between these two approaches. It was observed that in conducting an LCA study of a product or service, the definition of the objective and scope of the study is fundamental to the choice of which LCA methodology is applied. It was also observed that there are methodological limitations to both attributional LCA and consequential LCA. In case of attributional LCA, for example, there are uncertainties related to the subjective choice of the allocation method of co-products. In case of consequential LCA, the results may be more sensitive and more susceptible to uncertainties due to inclusions of trend studies and market projections for choosing marginal data and technologies, and for forecast data.
47

Contribution to climate change of a proposed horse manurecomposting system

Nordlund, Sara January 2017 (has links)
Hästar producerar gödsel som är en   blandning av avföring, urin och det strömaterial som hästarna står på.   Hippologum är en ridanläggning i Umeå (Västerbotten, Sverige) som producerar   20-25 ton gödsel per vecka och när denna rapport skrevs hade anläggningen   ingenstans att lagra gödseln. Detta var våren 2016. Målet med denna studie var att   undersöka ett möjligt förvaltning- och komposteringssystem för hästgödsel   mellan Hippologum och deponi- och avfallscentret Dåva DAC (som också är   beläget i Västerbotten, Sverige) och var systemets största klimatpåverkan   finns. En liten marknads-undersökning baserad på personintervjuer och ett   kort kapitel om lagaspekter finns också med i rapporten. Enligt den screening livscykelanalys som genomfördes   inom ramen för denna C-uppsats är den största klimatförändrande effekten för   23 ton hästgödsel från Hippologum till Dåva DAC odlingen av fodret.   Marknadsundersökningen som utfördes kan inte direkt säga att det finns en   marknad i Umeå kommun för komposterad hästgödsel. Gällande den lagliga biten   så kan sägas att EU har mycket att säga till om gällande animaliska   biprodukter och att den lagliga aspekten tyckts vara väl utvecklad. / Horses   produce feces and urine and this mixed with a bedding material such as   sawdust or cutterdust gives you horse manure. Hippologum is an equestrian   facility in Umeå (county of Västerbotten, Sweden) which produces 20-25 tons   of manure per week and when this report was written the facility had some   trouble to get rid off the manure. This was in Spring 2016. The aim of this study is to look into the possible soil   improver production as a management strategy for the horse manure produced at   Hippologum and the report also looks   into which part of this proposed system which has the greatest climate   impact. The landfill- and waste   center Dåva DAC (also located in the county of Västerbotten, Sweden) is the   assumed receiver of the manure, and this is were the manure would be refined   (composted). Research based on personal interviews about the manure market in   Umeå municipality as well as a short chapter about legal aspects of manure   are also included in the report. According to the screening LCA conducted during this   thesis work the greatest impact for 23 tons of horse manure from Hippologum   to Dåva DAC is the cultivation of the   fodder. The report cannot conclude if there is a manure market in Umeå   municipality. Concerning the legal aspects it can be said that the European   Union has well developed legislation concerning animal by-products and   regulates many aspects of handling and treating of horse manure. / <p>2019-01-08</p>
48

Associations tanins-bore pour des produits de protection du bois à faible impact environnemental / Tannins-boron networks for long-term and low-environmental impact wood preservatives

Hu, Jinbo 01 September 2015 (has links)
Étant donné son origine, le bois reste biodégradable et a besoin d'être protégé contre les agents abiotiques et biotiques afin d'avoir une longue durée de service. Les associations entre les tanins et l'acide borique peuvent être considérés comme un traitement innovant et respectueux de l'environnement. Ces formulations aqueuses de tannins et d'acide borique augmentent la rémanence du bore dans le bois traité. De plus, le bore est partiellement fixé au réseau polymère de tannins autocondensés dans le bois et garde suffisamment de mobilité pour garder son efficacité biologique. Ces associations ont été testées pour une application en extérieur, au-dessus et dans le sol, et pour leurs propriétés ignifugeantes. Une première formulation de tannin-hexamine et acide borique a montré une efficacité certaine face aux dégradations biologiques et au feu. Le comportement au vieillissement naturel et artificiel, au lessivage à l'échelle du laboratoire, ainsi que l'efficacité biologique résultante, de bois traité par ces associations a été étudié. Les résultats montent que ces trois vieillissements mènent à des performances biologiques différentes, toutes liées à la teneur en bore résiduelle. Une formulation tannin-bore dite améliorée, contenant du ɛ-caprolactame pour rendre le réseau polymère plus flexible (et éviter les craquelures comme dans la première formulation) a été étudiée pour les mécanismes chimiques mis en jeu, la résistance biologique au-dessus et dans le sol, et la résistance au feu. Le polymère à base de tannin acquiert une structure plus élastique après incorporation de ɛ-caprolactame, comme démontré par des analyses FT-IR. La résistance biologique du bois traité procure une résistance à long terme en extérieur, même dans le sol. L'effet de protection au feu est moins intéressant que pour la première formulation, mais reste toute de même plus important que pour le témoin. Afin d'améliorer l'efficacité des associations entre bore et tannins, l'élaboration de bois contenant un polymère nano-composite (Wood Tannin NanoComposite, WTNC) utilisant tannins, acide borique et montmorillonite a été étudiée. Des analyses FT-IR et XRD on permit d’identifier des nanoparticules d'argiles dans le WTNC. Par ailleurs, des traces de montmorillonite dans les parois du bois ont été observées en microscopie électronique à balayage. Par comparaison avec des témoins, la résistance à la compression du WTNC est plus importante, l'absorption d'eau et l'aptitude au collage du WTNC dépend de l'essence utilisée (pin sylvestre vs. Hêtre), la stabilité dimensionnelle du WTNC est légèrement abaissée et sa mouillabilité significativement réduite. La résistance à l'attaque de champignons et termites est améliorée dans des proportions variables selon que l'on utilise du pin sylvestre ou du hêtre. Les performances anti-feu des WTNC sont affectées différemment en fonction de l'essence de bois utilisée et des paramètres considérés. Cette étude analyse aussi les impacts environnementaux de la production de produit de préservation tannin-bore (pour la première formulation) et compare aussi les impacts du berceau à la tombe dans le cadre d'une analyse de cycle de vie de bois traité par cette formulation, en comparaison avec 2 formulations industrielles et du béton. Il apparaît que même si ces associations tannin-bore peuvent être encore étudiées plus avant et plus finement du point de vue chimique, pour leurs performances biologiques (vis-à-vis d'insectes coléoptères, essais de champ avec des termites, moisissures…), ainsi que pour leur profil éco-toxicologique, elles ont montré de réelles améliorations du bois dans les domaines de la résistance biologique et de la résistance au feu. / Due to its origins, wood remains biodegradable and needs to be protected against abiotic and biotic agents for a long service life. Tannin-boron associations can be considered as an innovative preservative formulation and environmentally-friendly treatment. These waterborne associations of tannins and boric acid increase the permanence of boron in the wood. Furthermore, boric acid is partly fixed to the network of autocondensed tannin in the wood and keeps sufficient mobility to maintain its biological action. These associations have been investigated for their outdoor applications, both above and in-ground, as well as for their ability for fire protection. An original formulation of tannin-hexamine and boric acid, has shown efficiency against biological attack and fire degradation. The natural and artificial weathering behaviour, and laboratory scale leaching, of such treated wood have been investigated, and followed by biological tests. The results showed that the weatherings led to different performances, always linked with the amount of remaining boron. An advanced tannin-boron formulation including ɛ-caprolactam to make the polymer network more flexible (and avoiding cracks as noticed for the original formulation) was studied for the chemical mechanisms, biological resistance above and in-ground, fire retardancy. The tannin polymer acquires a more elastic structure after adding ɛ-caprolactam, as seen with FT-IR analyses. The biological resistance of the treated wood provided a long lasting protection against degradation in outdoor exposures, and even in ground contact. However, fire retardant effect of this advanced tannin-boron preservative was negatively influenced with comparison to the original tannin-boron formulation, but still better than control. In order to improve the associations between boron and tannin for wood protection, the conception of wood polymer nanocomposite using tannin, boric acid and montmorillonite tentatively carried out. The analyses of FT-IR and XRD have investigated to identify nanoclay in Wood Tannin Nanocomposite (WTNC). Meanwhile, the trace of montmorillonite in wood cell is also captured by SEM. By comparison with control, compression strengths of WTNC samples increase; water absorption and gluing ability of WTNC depend on the wood species used (Scot Pine vs. Beech); dimensional stability of WTNC is slightly decreased, and wettability was significantly decreased. Fungal and termite resistance of WTNC are improved to different extends if Scots pine or beech samples are used. Fire performances of WTNC is affected differently depending on the wood species used and the parameters considered. This study also analyses the environmental impacts of producing tannin-boron (TB) preservative (the original formulation) and comparatively introduces the cradle-to-grave life cycle environmental impacts (LCA) of TB-treated timber as landscaping materials, compared with 2 industrial formulations and concrete.Even if all these tannin-boron association systems developed still need to be improved for some point of their chemistry, biological performances (coleoptera insects, field tests with termites, molds…), as well as for their eco-toxicological profile, they have shown to improve the biological and fire resistance of the wood.
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Life cycle assessment of bridges, model development and case studies

Du, Guangli January 2015 (has links)
In recent decades, the environmental issues from the construction sector have attracted increasing attention from both the public and authorities. Notably, the bridge construction is responsible for considerable amount of energy and raw material consumptions. However, the current bridges are still mainly designed from the economic, technical, and safety perspective, while considerations of their environmental performance are rarely integrated into the decision making process. Life Cycle Assessment (LCA) is a comprehensive, standardized and internationally recognized approach for quantifying all emissions, resource consumption and related environmental and health impacts linked to a service, asset or product. LCA has the potential to provide reliable environmental profiles of the bridges, and thus help the decision-makers to select the most environmentally optimal designs. However, due to the complexity of the environmental problems and the diversity of bridge structures, robust environmental evaluation of bridges is far from straightforward. The LCA has rarely been studied on bridges till now. The overall aim of this research is to implement LCA on bridge, thus eventually integrate it into the decision-making process to mitigate the environmental burden at an early stage. Specific objectives are to: i) provide up-to-date knowledge to practitioners; ii) identify associated obstacles and clarify key operational issues; iii) establish a holistic framework and develop computational tool for bridge LCA; and iv) explore the feasibility of combining LCA with life cycle cost (LCC). The developed tool (called GreenBridge) enables the simultaneous comparison and analysis of 10 feasible bridges at any detail level, and the framework has been utilized on real cases in Sweden. The studied bridge types include: railway bridge with ballast or fix-slab track, road bridges of steel box-girder composite bridge, steel I-girder composite bridge, post tensioned concrete box-girder bridge, balanced cantilever concrete box-girder bridge, steel-soil composite bridge and concrete slab-frame bridge. The assessments are detailed from cradle to grave phases, covering thousands of types of substances in the output, diverse mid-point environmental indicators, the Cumulative Energy Demand (CED) and monetary value weighting. Some analyses also investigated the impact from on-site construction scenarios, which have been overlooked in the current state-of-the-art. The study identifies the major structural and life-cycle scenario contributors to the selected impact categories, and reveals the effects of varying the monetary weighting system, the steel recycling rate and the material types. The result shows that the environmental performance can be highly influenced by the choice of bridge design. The optimal solution is found to be governed by several variables. The analyses also imply that the selected indicators, structural components and life-cycle scenarios must be clearly specified to be applicable in a transparent procurement. This work may provide important references for evaluating similar bridge cases, and identification of the main sources of environmental burden. The outcome of this research may serve as recommendation for decision-makers to select the most LCA-feasible proposal and minimize environmental burdens. / <p>QC 20150311</p>
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Kvalitets- och kostnadsanalys för användningen av miljöcertifieringssystemet Miljöbyggnad samt en förstudie av livscykelanalyser för byggprocessen

Sandstedt, Catrine January 2015 (has links)
The application of environmental assessment methods for buildings has increased significantly over the last few years. Approximately five years ago Riksbyggen decided to apply Miljöbyggnad Silver to the new construction of all their apartment buildings. Internally within the organisation, however, criticism that the system causes large design and construction costs has been lifted. The aim of this study was to investigate the magnitude of the design and construction expenses related to Miljöbyggnad and to find what improvements could be implemented to reduce costs and enforce the efficiency of the process. The second part of the study included a feasibility study regarding implementing Life Cycle Assessment, LCA, in the construction process. The purpose of including LCA would be to construct buildings with a reduced climate impact. There are convincing indications that LCA will become an increasingly important tool in the construction industry in the future.   The project leaders working with Miljöbyggnad at Riksbyggen completed a questionnaire considering the expenses Miljöbyggnad Silver causes beyond Boverket’s Building Regulations,as well as determining the attitude regarding a possible implementation of Life Cycle Assessment. The results were subsequently discussed more qualitatively during follow-up meetings and additionally with other professionals in the industry.   The project leaders' perception of the prevailing expenses associated with Miljöbyggnad Silver beyond the Boverket’s Building Regulations varied greatly, which was consistent with previous international studies. The total cost of the use of Miljöbyggnad was stated in the large range of 400.000 to 3.800.000 SEK, but when the most divergent estimates were excluded, a more limited range of 400.000 to 650.000 SEK was given. The project leaders estimated that the certification increased the project's total cost to an extent of 0.13 to 8%, but when excluding the most divergent estimates the interval was reduced to 0.13 to 2%. The project managers’ merged results emphasized that the most cost-bearing indicators were, with the most costly first, solar heat load, daylight, thermal climate summer, absence of hazardous substances and documentation of materials.   The project leaders’ knowledge regarding LCA was limited. The main reason for their reluctance to implementation seemed to be the additional work and expense it could entail. In principle, all project leaders were of the opinion that LCA should be integrated in an early project stage prior to the procurement of a contractor. / Tillämpningen av miljöcertifieringar för byggnader har de senaste åren ökat kraftigt i omfattning. Riksbyggen tillämpar sedan några år tillbaka Miljöbyggnad ambitionsnivå Silver för all nyproduktion av flerbostadshus. Internt inom organisationen har dock kritik framhållits avseende att systemet föranleder stora ökningar av investeringskostnaderna. Eftersom få studier beträffande eventuella merkostnader av miljöcertifieringssystem genomförts har det för Riksbyggen varit svårt att svara på kritiken. Syftet med studien var följaktligen att utreda investeringskostnadernas omfattning samt vilka förbättringsåtgärder som skulle kunna vidtas för att reducera kostnaderna och parallellt stärka certifieringens ändamålsenlighet. Den andra delen av studien inbegriper en förstudie avseende en eventuell implementation av livscykelanalys, LCA, för byggprocessen. Mycket tyder på att LCA kommer att användas allt mer inom byggindustrin framöver för att uppföra byggnader med en reducerad klimatpåverkan.   Riksbyggens projektledare besvarade en enkätundersökning avseende de kostnader Miljöbyggnad Silver tillfogar utöver Boverkets byggregler, BBR, samt en undersökning avseende deras inställning till en eventuell implementation av livscykelanalyser. Enkätundersökningen kompletterades med uppföljningsmöten under vilka enkätresultaten diskuterades mer kvalitativt samt genom möten med andra professionellt yrkesverksamma.   Projektledarnas perception av kostnaderna förenade med Miljöbyggnad Silver utöver BBR varierade kraftigt, vilket dock överensstämde med tidigare internationellt genomförda studier. Totalkostnaderna för certifieringen befann sig i ett intervall av 400–3800 tusen kronor, tkr, men då de mest avvikande uppskattningarna exkluderades begränsades kostnadsintervallet till 400–650 tkr. Projektledarna uppskattade att certifieringen innebar ett kostnadspåslag på projektets totalkostnad av 0,13 till 8 %, men då extremerna exkluderades begränsades intervallet till 0,13–2 %. Projektledarnas sammanslagna resultat indikerade att de mest kostnadsdrivande indikatorerna var, med den mest kostnadsdrivande först; solvärmelast, dagsljusfaktor, termiskt klimat sommar, utfasning av farliga ämnen samt dokumentation av byggvaror. Projektledarnas kunskapsbild avseende LCA var relativt begränsad och de främsta betänkligheterna beträffande en implementering tycks vara den eventuella arbetsbelastning det skulle kunna medföra samt de kostnader det skulle driva. Den viktigaste frågan beträffande en LCA-implementering är hur Riksbyggen på bästa sätt integrerar livscykelperspektivet i verksamheten. Majoriteten av projektledarna var av åsikten att LCA vid en implementering bör integreras i ett tidigt projektstadium framför vid upphandling av entreprenör.

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