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Seleção de fronteiras para análise de ciclo de vida de sistemas que emitem poluentes tóxicos de chaminés / Boundary selection for LCA of systems with toxic stack emissionsMatos, Stelvia Vigolvino 17 September 2002 (has links)
Este trabalho desenvolve um método de seleção de fronteiras para Análise de Ciclo de Vida (ACV) de sistemas que emitem componentes tóxicos. Isto envolve o desenvolvimento de um modelo de predição de concentração e dose de poluentes emitidos de chaminés, que tem a vantagem de ser simples e não requerer grande número de dados de entrada. Esse modelo e mais os dados de valoração econômica de danos ambientais disponíveis na literatura, compõem o modelo geral de estimativa de custos devido à emissão de poluentes, ou seja, a Análise de Custos em Ciclo de Vida (ACCV). O modelo geral é então usado para definir as fronteiras do sistema de ACCV. Demonstra-se a aplicação do novo método em um ciclo de vida hipotético de produção de celulose. / This work develops a method for Boundary Selection (BS) for Life Cycle Assessment (LCA) of systems with stacks emitting toxics compounds. The new approach involves the development of a model of concentrations and dosage of pollutants in the vicinity of emission source that is simple and non-intensive data is required. This model plus impact costs estimations available at environmental economic studies, comprise the general model of Life Cycle Cost Analysis (LCCA) based on exposure. This general model is then used in the Boundary Selection in LCCA. A demonstration of the application of the model is performed to a hypothetical inventory system of a pulp mill.
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Seleção de fronteiras para análise de ciclo de vida de sistemas que emitem poluentes tóxicos de chaminés / Boundary selection for LCA of systems with toxic stack emissionsStelvia Vigolvino Matos 17 September 2002 (has links)
Este trabalho desenvolve um método de seleção de fronteiras para Análise de Ciclo de Vida (ACV) de sistemas que emitem componentes tóxicos. Isto envolve o desenvolvimento de um modelo de predição de concentração e dose de poluentes emitidos de chaminés, que tem a vantagem de ser simples e não requerer grande número de dados de entrada. Esse modelo e mais os dados de valoração econômica de danos ambientais disponíveis na literatura, compõem o modelo geral de estimativa de custos devido à emissão de poluentes, ou seja, a Análise de Custos em Ciclo de Vida (ACCV). O modelo geral é então usado para definir as fronteiras do sistema de ACCV. Demonstra-se a aplicação do novo método em um ciclo de vida hipotético de produção de celulose. / This work develops a method for Boundary Selection (BS) for Life Cycle Assessment (LCA) of systems with stacks emitting toxics compounds. The new approach involves the development of a model of concentrations and dosage of pollutants in the vicinity of emission source that is simple and non-intensive data is required. This model plus impact costs estimations available at environmental economic studies, comprise the general model of Life Cycle Cost Analysis (LCCA) based on exposure. This general model is then used in the Boundary Selection in LCCA. A demonstration of the application of the model is performed to a hypothetical inventory system of a pulp mill.
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A second-order cybernetic explanation for the existence of network direct selling organisations as self-creating systemsDavis, Corne 18 August 2011 (has links)
Network Direct Selling Organisations (NDSOs) exist in more than 50 countries and have more than 74 million members. The most recent statistical information reveals that the vast majority of members do not earn significant income. Criticism of these organisations revolves around the ethicality of consumption, the commercialisation of personal relationships, and the exploitation of unrealistic expectations. This study aims to explore how communication creates networks that sustain an industry of this kind despite the improbability of its existence.
The study commences with a description of NDSOs from historical, operational, tactical, and strategic perspectives. Given the broader context created by the global presence of this industry, cybernetics has been selected as a meta-theoretical perspective for the study of communication. The more recent development of second-order cybernetics and social autopoiesis are introduced to communication theory as a field. Niklas Luhmann‟s new social theory of communication is assessed and applied in relation to existing communication theory.
New conceptual models are developed to explore communication as the unity of the synthesis of information, utterance, understanding, and expectations as selections that occur both consciously and unconsciously, intentionally and unintentionally. These models indicate the multiplexity of individual and social operationally closed, yet informationally open systems, and they are used here to provide a systemic and coherent alternative to orthodox communication approaches to the study of organisations. The study adopts a constructivist epistemological stance and propounds throughout the necessity of further interdisciplinary collaboration.
The study concludes that individuals are composite unities of self-creating systems, and they co-create social systems by self-creating and co-creating meaning. Meaning is described as the continuous virtualisation and actualisation of potentialities that in turn coordinate individual and social systems‟ actions. A communication process flow model is created to provide a theoretical explanation for the existence of NDSOs as self-creating systems. The study aims to show that communication has arguably become the most pervasive discipline as a result of the globally interactive era. It is shown that second-order cybernetics and social autopoiesis raise several further questions to be explored within communication theory as a field. / Communication, first-order cybernetics, second-order cybernetics, Complexity and complex systems, autopoiesis, self-reference, recursivity, operational closure, system boundaries, Network Direct Selling Organisations / Communication / D. Litt. et Phil. (Communication)
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A second-order cybernetic explanation for the existence of network direct selling organisations as self-creating systemsDavis, Corne 18 August 2011 (has links)
Network Direct Selling Organisations (NDSOs) exist in more than 50 countries and have more than 74 million members. The most recent statistical information reveals that the vast majority of members do not earn significant income. Criticism of these organisations revolves around the ethicality of consumption, the commercialisation of personal relationships, and the exploitation of unrealistic expectations. This study aims to explore how communication creates networks that sustain an industry of this kind despite the improbability of its existence.
The study commences with a description of NDSOs from historical, operational, tactical, and strategic perspectives. Given the broader context created by the global presence of this industry, cybernetics has been selected as a meta-theoretical perspective for the study of communication. The more recent development of second-order cybernetics and social autopoiesis are introduced to communication theory as a field. Niklas Luhmann‟s new social theory of communication is assessed and applied in relation to existing communication theory.
New conceptual models are developed to explore communication as the unity of the synthesis of information, utterance, understanding, and expectations as selections that occur both consciously and unconsciously, intentionally and unintentionally. These models indicate the multiplexity of individual and social operationally closed, yet informationally open systems, and they are used here to provide a systemic and coherent alternative to orthodox communication approaches to the study of organisations. The study adopts a constructivist epistemological stance and propounds throughout the necessity of further interdisciplinary collaboration.
The study concludes that individuals are composite unities of self-creating systems, and they co-create social systems by self-creating and co-creating meaning. Meaning is described as the continuous virtualisation and actualisation of potentialities that in turn coordinate individual and social systems‟ actions. A communication process flow model is created to provide a theoretical explanation for the existence of NDSOs as self-creating systems. The study aims to show that communication has arguably become the most pervasive discipline as a result of the globally interactive era. It is shown that second-order cybernetics and social autopoiesis raise several further questions to be explored within communication theory as a field. / Communication, first-order cybernetics, second-order cybernetics, Complexity and complex systems, autopoiesis, self-reference, recursivity, operational closure, system boundaries, Network Direct Selling Organisations / Communication / D. Litt. et Phil. (Communication)
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Exploring the relevance of uncertainty in the life cycle assessment of forest productsRøyne, Frida January 2016 (has links)
The role of forest biomass as a replacement for fossil fuels and products is becoming increasingly prominent as a means to mitigate climate change. To guide a sustainable transition towards a forest-based bio-economy, it is important that advantages and disadvantages of forest products are assessed, to ensure that the products deliver environmental impact reduction. Life Cycle Assessment (LCA) has become heavily relied upon for assessing the environmental impact of bio-based products. However, LCAs of similar product systems can lead to results that differ considerably, and the method is, thus, associated with uncertainties. It is, therefore, necessary to explore the relevance of uncertainties, to build knowledge about enablers and challenges in using LCA for assessing forest products. Three important challenges in the context of uncertainty in LCA are the focus of this thesis: 1) system boundaries, 2) climate impact assessment practice, and 3) allocation. More specifically, the relevance of a) including and excluding life cycle phases, b) potentially important climate aspects, and c) applying different allocation methods, was assessed. Case studies involved a chemical industry cluster, a biorefinery, and single product value chains for a plastic box, a fuel, and a building. In summary, the thesis demonstrates that: A major share of the environmental impact related to the production of an industry cluster can occur outside the cluster gates, so when strategies involving a transition to forest biomass feedstock are developed and evaluated, a life cycle perspective reveals the full environmental impact reduction potential. For bio-based products differing in functional properties from the fossil products they are meant to replace, material deterioration in the use phase can contribute substantially to overall environmental performance. This is acknowledged if all life cycle phases are regarded. As climate aspects commonly not assessed in forest product LCAs could influence results greatly, and even affect the outcome of comparisons between forest and non-forest products, the climate impact of forest products is uncertain. It is, therefore, important that this uncertainty is acknowledged and communicated, and that appropriate methods and guidelines are developed. The choice of allocation method in the LCA of biorefinery products can have a major influence on results, especially for physically non-dominant products and in consequential studies. In these cases, scenario analysis is especially valuable to show the possible range of results. LCA provides useful guidance for forest product development and production as the life cycle approach reveals causes of environmental impact throughout the product value chain. Proper identification, estimation, and management of uncertainties strengthen the provision of reliable decision support. / Att ersätta fossila bränslen och produkter med skogsbiomassa blir ett allt viktigare sätt att försöka minska klimatförändringen. För att säkerställa en hållbar övergång till en skogsbaserad bioekonomi är det viktigt att fördelarna och nackdelarna med skogsprodukter bedöms, för att klargöra att de faktiskt ger minskad miljöpåverkan. Livscykelanalys (LCA) är en flitigt använd metod för att bedöma miljöpåverkan från biobaserade produkter. Dock kan LCA:er på snarlika produktsystem komma fram till resultat som skiljer sig avsevärt. Metoden är således förknippad med osäkerheter. Det är därför nödvändigt att undersöka betydelsen av osäkerheter och därigenom bygga upp kunskap om förutsättningar för och utmaningar i användningen av LCA för bedömning av skogsprodukters miljöprestanda. Avhandlingen fokuserar på tre viktiga utmaningar som alla rör osäkerheter i LCA: 1) systemgränser, 2) praxis vid bedömning av klimatpåverkan, och 3) allokering. Närmare bestämt bedöms betydelsen av a) inkluderandet och exkluderandet av livscykelfaser, b) potentiellt viktiga klimataspekter och c) olika allokeringsmetoder. Fallstudier har gjorts på ett kemiskt industrikluster, ett bioraffinaderi och produktvärdekedjorna för en plastlåda, ett fordonsbränsle samt en byggnad. Sammanfattningsvis visar avhandlingen att: En stor del av miljöpåverkan relaterad till ett industriklusters produktion kan uppstå utanför klustrets grindar. När strategier som innebär en övergång till skogsbasserat råmaterial utvecklas och utvärderas är det således viktigt att använda ett livscykelperspektiv, så att den fulla potentialen för minskad miljöpåverkan synliggörs. För biobaserade produkter som skiljer sig i funktionella egenskaper från de fossila produkter de är avsedda att ersätta riskerar materialförsämring i användningsfasen att väsentligt minska den övergripande miljöprestandan. Om detta är fallet framgår tydligt om alla livscykelfaser beaktas. Klimataspekter som vanligtvis inte bedöms i LCA-studier på skogsprodukter kan påverka resultatet kraftigt och även påverka resultatet av jämförelser mellan skogs och icke-skogsprodukter. Således är den faktiska klimatpåverkan av skogsprodukter osäker. Det är därför viktigt att osäkerheten uppmärksammas och kommuniceras samt att lämpliga metoder och riktlinjer för bedömning av klimatpåverkan från skogsprodukter utvecklas. I LCA av bioraffinaderiprodukter kan val av allokeringsmetod ha en stor inverkan på resultaten. Detta gäller särskilt för fysiskt icke-dominanta produkter och i konsekvensanalyser. I dessa fall är scenarioanalys speciellt värdefullt att använda för att visa möjliga skillnader i resultat. LCA ger värdefull vägledning för utveckling och produktion av skogsprodukter, då livscykeltänkandet beaktar orsakerna till miljöpåverkan i produkternas hela värdekedjor. Korrekt identifiering, uppskattning och hantering av osäkerheter stärker tillförlitligheten av beslutsunderlaget.
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Life cycle assessment of metal laser powder bed fusion : A deep dive into the significance of system boundary expansion and improvement potentialRotter, Christian, Fagerberg, Erik January 2023 (has links)
Metal additive manufacturing (MAM) is a manufacturing technology experiencing a rapid expansion rate. Metal laser powder bed fusion (ML-PBF) is among the most popular techniques in this field. The environmental implications of it are often discussed in literature and compared to conventional manufacturing. However, the system in its entirety, from a cradle-to-gate perspective, has not seen intense scrutiny so far. A Life Cycle Assessment (LCA) often serves as the evaluation method when investigating environmental impacts; however, this method has been proven to be complex and time-consuming. Efforts are made to reduce this burden by, among others, developing streamlined LCA tools for MAM. This thesis presents three different life cycle assessments, each with different system boundaries, methodologies, and data qualities. In all of them, Global Warming Potential (GWP) and CO2 emissions are focused on. The aim of this thesis is to investigate how large the environmental impact of ML-PBF is when considering the whole system, and to compare this to a streamlined assessment, per kilogram of printed AlSi10Mg based on an average production scenario. The database ecoinvent v.3 and the characterization method ReCiPe 2016 midpoint (H) are used for the analysis with wider system boundaries in combination with specific data. Whereas a third-party streamlined LCA tool is used for the LCA with narrower system boundaries, using the specific energy content of the material. Previous research in the field of ML-PBF often neglects the impact of inert gas and attributes a large portion of the impact to processing electricity. Moreover, post-processing and machine impacts are usually not included in the system boundaries but have been advocated by many to be worth investigating. The results in this thesis show that in contrast to previous research, argon gas accounted for the biggest GWP and where process electricity accounted for less than half of argon. A system boundary expansion was also found to lead to an increase of nearly 230 % of CO2 eq emissions, making it significant to the analysis. Many minuscule factors such as machining, various losses, idle time, machine impact and compressed air contributed to this contrast. Combining this with an improvement and generalizability analysis showed that the global warming potential associated with ML-PBF can be lowered by more than 75 % through either altering the electricity mix or optimizing process parameters, both at the company and upstream. Additionally, it was discovered that the LCA calculation method, and deviations in data quality, contributed to a higher difference in the environmental impact than expanding the system boundaries.
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Exploring unregulated climate offsetting as a means for private consumers to mitigate climate change : An analysis of 15 offset claims within the food and aviation sectors / Undersökning av oreglerad klimatkompensation som medel för att motverka klimatförändringar : En analys av 15 påståenden om klimatkompensation inom mat-och flygbranschenAgering, Astrid, Cervall, Teodor January 2022 (has links)
Climate change has been described as “the greatest and widest-ranging market failure ever seen”. Unregulated climate offsetting has emerged as a way for consumers to internalize the externality of climate change. Previous research abounds regarding the challenges facing the technical performance of climate offsetting, but this research has not taken into account how the interpretation of consumers will affect the ability of offsetting to mitigate climate change. Therefore, in this report, a conceptual framework illustrating possible challenges was constructed based on the technical performance of offsetting as well as marketing laws and guidelines, while adding an explicit use of system boundaries. Making use of manifest content analysis, the framework was then empirically tested through analyzing offset claims from the aviation and food retail sectors. Large risks of consumer misinterpretations of offset claims were found within all investigated system boundaries and for both sectors. As such, it seems that unregulated climate offsetting has inherited the well-known problems related to regulated climate offsetting while failing to address the general issues of environmental marketing. Until and unless these issues are addressed, unregulated climate offsetting should be used with caution as a way to mitigate climate change. / Klimatkrisen har beskrivits som “det främsta och mest omfattande marknadsmisslyckandet som någonsin skådats”. Oreglerad klimatkompensation har vuxit fram som ett sätt för konsumenter att internalisera externaliteterna associerade med klimatkrisen. Tidigare forskning har undersökt de tekniska utmaningarna som klimatkompensation står inför, men denna forskning har inte tagit hänsyn till hur konsumenternas uppfattning av fenomenet kommer påverka klimatkompensationens förmåga att mildra klimatkrisen. Därför utvecklade denna studie ett konceptuellt ramverk för att illustrera klimatkompensationens möjliga utmaningar, baserat på den tekniska prestandan såväl som marknadsföringslagar och riktlinjer. Till detta adderades en explicit användning av systemgränser. Genom manifest innehållsanalys testades ramverket sedan empiriskt genom att analysera marknadsföringspåståenden kopplade till klimatkompensation inom sektorerna livsmedelshandel och flyg. Stora risker för missförstånd upptäcktes inom båda sektorerna och inom alla fyra relevanta systemgränser. Detta pekar mot att oreglerad klimatkompensation har ärvt de väletablerade problemen kopplade till den reglerade marknaden inom klimatkompensation samtidigt som de generella problemen kopplade till miljöpåståenden inte har adresserats. Om dessa utmaningar inte tas hänsyn till, bör oreglerad klimatkompensation användas med försiktighet om målet är att verka som en lindrande åtgärd för klimatkrisen.
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