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Shimako, Allan. "Contribution to the development of a dynamic Life Cycle Assessment method." Thesis, Toulouse, INSA, 2017. http://www.theses.fr/2017ISAT0014/document.
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L'analyse du cycle de vie (ACV) est une méthode très utilisée pour l'évaluation environnementale d'un système anthropique. Les spécialistes ont souligné l'absence de dimension temporelle comme une limitation. Les procédés de la technosphère sont dynamiques, ce qui conduirait à un inventaire de cycle de vie (ICV) dépendant du temps. Les mécanismes environnementaux impliqués dans la génération des impacts ont des caractéristiques dynamiques variées déterminant une manifestation temporelle spécifiques des impacts. Cependant, l’impact du cycle de vie (EICV) actuelles considère des modèles en conditions stationnaires et des horizons de temps arbitrairement fixés. L'objectif de cette thèse est de contribuer au développement d'une méthodologie opérationnelle et des outils adaptés pour la prise en compte du temps dans l'ACV, en accordant une importance au développement d'une approche de modélisation intégrée pour l’ICV et l’EICV. La première contribution de cette thèse concerne le développement d'une base de données temporelle, en s'appuyant sur la base de données ecoinvent, dans laquelle les paramètres temporels ont été attribués aux sets de données. Des indicateurs dynamiques pour le changement climatique et la toxicité ont été développés en adaptant les modèles disponibles et ils ont été mis en place dans un outil de calcul propre. L'approche de modélisation tient compte de la nature fluctuante des émissions des substances en fonction du temps calculées par le modèle d’ICV temporel DyPLCALife Cycle Assessment (LCA) is a widely used method for the environmental evaluation of an anthropogenic system. However, LCA scholars pointed out the lack of a temporal dimension as a limitation. The processes of technosphere are dynamic which leads to a time dependent life cycle inventory (LCI). Environmental mechanisms involved in impact developments have distinct dynamic behaviors determining specific temporal occurrence. However, the current life cycle impact assessment (LCIA) methods consider arbitrarily fixed time horizons and/or steady state conditions. The objective of this thesis is to contribute to the development of an operational methodology and adapted tools for the consideration of time dependency in LCA, with emphasis on the development of an integrated modelling solution for both the life cycle inventory and the life cycle impact assessment phases. The first contribution of this thesis concerns the development of a temporal data base, leaning against ecoinvent data base, in which temporal parameters have been attributed to the data sets. Dynamic climate change and toxicity impacts were developed by adapting available models and were implemented in a homemade computational tool. The modelling approach takes into account the noisy nature of substance emissions in function of time as calculated by DyPLCA temporal LCI model
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Collinge, William O. "A dynamic life cycle assessment framework for whole buildings including indoor environmental quality impacts." Thesis, University of Pittsburgh, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3573266.
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Life cycle assessment (LCA) can aid in quantifying the environmental impacts of whole buildings by evaluating materials, construction, operation and end of life phases with the goal of identifying areas of potential improvement. Since buildings have long useful lifetimes, and the use phase can have large environmental impacts, variations within the use phase can sometimes be greater than the total impacts of other phases. Additionally, buildings are operated within changing industrial and environmental systems; the simultaneous evaluation of these dynamic systems is recognized as a need in LCA. At the whole building level, LCA of buildings has also failed to account for internal impacts due to indoor environmental quality (IEQ). The two key contributions of this work are 1) the development of an explicit framework for DLCA and 2) the inclusion of IEQ impacts related to both occupant health and productivity. DLCA was defined as “an approach to LCA which explicitly incorporates dynamic process modeling in the context of temporal and spatial variations in the surrounding industrial and environmental systems.” IEQ impacts were separated into three types: 1) chemical impacts, 2) nonchemical health impacts, and 3) productivity impacts. Dynamic feedback loops were incorporated in a combined energy/IEQ model, which was applied to an illustrative case study of the Mascaro Center for Sustainable Innovation (MCSI) building at the University of Pittsburgh. Data were collected by a system of energy, temperature, airflow and air quality sensors, and supplemented with a postoccupancy building survey to elicit occupants’ qualitative evaluation of IEQ and its impact on productivity. The IEQ+DLCA model was used to evaluate the tradeoffs or co-benefits of energy-savings scenarios. Accounting for dynamic variation changed the overall results in several LCIA categories—increasing nonrenewable energy use by 15% but reducing impacts due to criteria air pollutants by over 50%. Internal respiratory effects due to particulate matter were up to 10% of external impacts, and internal cancer impacts from VOC inhalation were several times to almost an order of magnitude greater than external cancer impacts. An analysis of potential energy saving scenarios highlighted tradeoffs between internal and external impacts, with some energy savings coming at a cost of negative impacts on either internal health, productivity or both. Findings support including both internal and external impacts in green building standards, and demonstrate an improved quantitative LCA method for the comparative evaluation of building designs.
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Negishi, Koji. "Development of a methodology of Dynamic LCA applied to the buildings." Thesis, Toulouse, INSA, 2019. http://www.theses.fr/2019ISAT0013/document.
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Le secteur du bâtiment est un acteur clé pour aider la France à atteindre ses objectifs de réduction en matière de consommation d’énergie et d’émissions de gaz à effet de serre (GES). L’analyse du cycle de vie (ACV) est la méthode la plus utilisée pour évaluer les impacts environnementaux d’un produit ou d’un système d’une manière systématique et holistique sur l’ensemble de son cycle de vie. Dans le secteur du bâtiment, la méthode ACV a été adaptée avec des outils appropriés, simplifiés, pour inciter les acteurs du bâtiment à évaluer la performance environnementale de leur produit. Cependant, la méthode ACV présente des limites dont une est le manque de notion de « temps », qui touche notamment trois points : (i) Manque de considération de l’évolution temporelle des systèmes, du système « bâtiment » dans notre cas, (ii) Non prise en compte du décalage temporel des activités et donc des émissions, and (iii) Non prise en compte du caractère dynamique des impacts environnementaux. Dans ce contexte, l’objectif de la thèse est de développer une méthodologie d’ACV dynamique appliquée au bâtiment, qui permet de prendre en compte ces trois aspects dynamiques, sur la base du projet ANR DyPLCA. L’application de la nouvelle méthode dynamique à un cas d’étude avec trois maisons individuelles accolées a permis d’obtenir des informations importantes sur le profil temporel des impacts. La même quantité des émissions de GES a un impact de changement climatique plus bas lorsque les émissions sont réparties sur une période longue. Les actions pour la réduction et l’adaptation doivent être décidées selon différents types de famille de produits de construction. Ainsi, il est nécessaire d’adapter les efforts de réduction d’impacts en fonction des substances chimiquesThe building sector is a key actor to meet the reduction targets in terms of energy consumption and greenhouse gases (GHG) emissions. Life Cycle Assessment (LCA) is the most used method for assessing the environmental impacts of a system. In the building sector, the LCA method was adapted with appropriate and simplified tools in order to encourage stakeholders to evaluate the environmental performance of their building products. However, LCA method has some limitations, one of which being the lack of “time dimension” that particularly concerns three points: (i) Lack of consideration of temporal evolution of the system under LCA study, “building system” in our case, (ii) Lack of consideration of temporal discrepancy of activities and associated emissions, (iii) Lack of consideration of dynamic characteristics of environmental impacts (stationary conditions, fixed time horizon, etc.). In this context, the primary objective of the thesis is to develop a dynamic LCA methodology applied to the building sector, on the basis of DyPLCA ANR project. The application of the new dynamic method to a case study with three attached single houses demonstrated that dynamic LCA provides important information on the temporal profile of impacts. The same amount of GHG emissions has a lower effect on temperature peaks when emissions are spread over a long period. The distinction is made between the various GHG, especially according to their lifetime. Instantaneous and cumulated effects (indicators) should be considered in a complete analysis. Actions for mitigation and adaptation need to be decided according to different types of construction product families. Besides, it is necessary to adapt the impact reduction efforts according to the chemical substances
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Ahmadi, Achachlouei Mohammad. "Exploring the Effects of ICT on Environmental Sustainability: From Life Cycle Assessment to Complex Systems Modeling." Doctoral thesis, KTH, Miljöstrategisk analys (fms), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171443.
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The production and consumption of information and communication technology (ICT) products and services continue to grow worldwide. This trend is accompanied by a corresponding increase in electricity use by ICT, as well as direct environmental impacts of the technology. Yet a more complicated picture of ICT’s effects is emerging. Positive indirect effects on environmental sustainability can be seen in substitution and optimization (enabling effects), and negative indirect effects can be seen in additional demand due to efficiency improvements (rebound effects). A variety of methods can be employed to model and assess these direct and indirect effects of ICT on environmental sustainability. This doctoral thesis explores methods of modeling and assessing environmental effects of ICT, including electronic media. In a series of five studies, three methods were at times applied in case studies and at others analyzed theoretically. These methods include life cycle assessment (LCA) and complex systems modeling approaches, including System Dynamics (SD) and agent-based (AB) modeling. The first two studies employ the LCA approach in a case study of an ICT application, namely, the tablet edition of a Swedish design magazine. The use of tablets has skyrocketed in recent years, and this phenomenon has been little studied to date. Potential environmental impacts of the magazine’s tablet edition were assessed and compared with those of the print edition. The tablet edition’s emerging version (which is marked by a low number of readers and low reading time per copy) resulted in higher potential environmental impacts per reader than did the print edition. However, the mature tablet edition (with a higher number of readers and greater reading time per copy) yielded lower impacts per reader in half the ten impact categories assessed. While previous studies of electronic media have reported that the main life-cycle contributor to environmental impacts is the use phase (which includes operational electricity use as well as the manufacture of the electronic device), the present study did not support those findings in all scenarios studied in this thesis. Rather, this study found that the number of readers played an important role in determining which life-cycle phase had the greatest impacts. For the emerging version, with few readers, content production was the leading driver of environmental impacts. For the mature version, with a higher number of readers, electronic storage and distribution were the major contributors to environmental impacts. Only when there were many readers but low overall use of the tablet device was the use phase the main contributor to environmental impacts of the tablet edition of the magazine. The third study goes beyond direct effects at product- and service-level LCAs, revisiting an SD simulation study originally conducted in 2002 to model indirect environmental effects of ICT in 15 European countries for the period 2000-2020. In the current study, three scenarios of the 2002 study were validated in light of new empirical data from the period 2000–2012. A new scenario was developed to revisit the quantitative and qualitative results of the original study. The results showed, inter alia, that ICT has a stimulating influence on total passenger transport, for it makes it more cost- and time-efficient (rebound effects). The modeling mechanism used to represent this rebound effect is further investigated in the fourth study, which discusses the feedback loops used to model two types of rebound effects in passenger transport (direct economic rebound and time rebound). Finally, the role of systems thinking and modeling in conceptualizing and communicating the dynamics of rebound effects is examined. The aim of the fifth study was to explore the power of systems modeling and simulation to represent nonlinearities of the complex and dynamic systems examined elsewhere in this thesis. That study reviews previous studies that have compared the SD and AB approaches and models, summarizing their purpose, methodology, and results, based on certain criteria for choosing between SD and AB approaches. The transformation procedure used to develop an AB model for purposes of comparison with an SD model is also explored. In conclusion, first-order or direct environmental effects of ICT production, use, and disposal can be assessed employing an LCA method. This method can also be used to assess second-order or enabling effects by comparing ICT applications with conventional alternatives. However, the assessment of enabling effects can benefit from systems modeling methods, which are able to formally describe the drivers of change, as well as the dynamics of complex social, technical, and environmental systems associated with ICT applications. Such systems methods can also be used to model third-order or rebound effects of efficiency improvements by ICT.Den ökande produktionen och konsumtionen av produkter och tjänster inom informations- och kommunikationsteknik (IKT) leder till en ökning av den globala elanvändningen samt direkta miljökonsekvenser kopplade till IKT. Men IKT har även indirekta miljömässiga effekter. Dessa kan vara positiva till exempel genom substitutions- och optimeringseffekter eller negativa genom att till exempel ge upphov till ytterligare efterfrågan på grund av effektivisering (så kallade reboundeffekter). Olika metoder kan användas för att modellera och bedöma både direkta och indirekta effekter av IKT. Syftet med denna avhandling är att undersöka metoder för modellering samt att studera miljöeffekter av IKT och elektronisk media med hjälp av livscykelanalys (LCA) och även modellering av komplexa och dynamiska system, samt simuleringsteknik, så som System Dynamics (SD) och agentbaserad (AB) modellering. Avhandlingen omfattar fem artiklar (artikel I-V). Artikel I & II beskriver resultaten från en fallstudie där miljöeffekter kopplade till en svensk tidskrift studeras med LCA. Tidskriftens version för surfplatta samt motsvarande tryckta version studeras och jämförs. Artikel III går ett steg vidare från produktnivåns LCA. Artikeln återkopplar till en SD simuleringsstudie som ursprungligen genomfördes under 2002. Simuleringsstudien gällde framtida miljöeffekter av IKT i 15 europeiska länder med tidspespektivet 2000-2020. I artikeln valideras tre scenarier från simuleringsstudien med hjälp av nya empiriska data från 2000-2012 och ett nytt scenario modelleras. Kvantitativa och kvalitativa resultat från den ursprungliga studien diskuteras. Till exempel visar artikel III att IKT har en stimulerande effekt på den totala persontrafiken genom att göra den mer kostnads- och tidseffektiv (reboundeffekt). Modelleringsmekanismen som används för att representera denna reboundeffekt diskuteras vidare i artikel IV. Artikeln belyser och diskuterar den återkopplingsslinga (feedback-loop) som används för att modellera två typer av reboundeffekter kopplade till persontrafik (direkt ekonomisk rebound och tidsrelaterad rebound) samt jämför med en tidigare studie. Artikel IV behandlar också den roll systemtänkande och modellering kan spela i konceptualisering och kommunikation av reboundeffekters dynamik. För att ytterligare undersöka systemmodelleringens och simuleringens möjligheter att representera icke-linjära komplexa och dynamiska system (exempel på sådana diskuteras i artikel III och IV), sammanställer artikel V tidigare studier som jämför SD och AB-metoder och -modeller. Studiernas mål och metod summeras och resultaten med avseende på vilka kriterier som presenteras för att välja mellan SD och AB sammanställs. Även processen för att omvandla en befintlig SD-modell till en AB-modell beskrivs. Avhandlingens slutsats är att LCA och systemmodelleringsmetoder kan vara användbara för att studera IKTs direkta effekter så väl som indirekta effekter på miljön.
QC 20150813
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Pettersen, Johan. "Potentially affected fraction of species from dynamic marine exposure : Life cycle impact assessment of marine ecotoxic impacts from offshore discontinuous discharges." Thesis, Norwegian University of Science and Technology, Industrial Ecology Programme, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1420.
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For any substance that is used and discharged offshore the contractor has to choose the best alternative in relation to the effects of the substance upon discharge. Any environmental impact that the choice might have in other localities related to either processes before the product is used (e.g. raw material extraction and refining), or in the following treatment of byproducts (offshore or on shore) are neglected. Basing the selection of products solely on the potential marine toxicological impact of the substances will systematically prioritize small local improvements to greater improvement potentials in production or internal and external recycling.
Life cycle impact assessment (LCA) is a tool developed for environmental evaluation of entire product systems; that is all processes for from raw material production to the end-of-life treatment of the product. Material input and output streams to the processes are converted to environmental impacts in the life cycle impact assessment (LCIA) stage of LCA. Characterization factors are used to quantify the impact within impact groups.
Eco-indicator 99 and the CLM problem oriented approach (CML-POA) are two LCIA methods that include characterization factors for eco-toxic impacts. Both methods use adapted versions of the EUSES/SimpleBox model to simulate the fate of substances, but the methods do not apply the same definition of eco-toxic damage to quantify the relative impact of different substances. Eco-indicator 99 uses the Potentially affected fraction of species (PAF), while CML-POA uses the Risk Characterization Ratio. EUSES/SimpleBox is a multi media steady-state fate model, and concentrations in different environmental media are calculated from annual continuous emissions.
Offshore discharges are distributed in time and space. The resulting concentrations are high compared to the concentration in the total marine volume, and the affected volume is limited. Given the discontinuous properties of exposure from offshore discharges the EUSES/SimpleBox model is not suited to model such emissions.
A method to calculate characterization factors for discontinuous offshore discharges is proposed in this study. The method is based on the PAF as defined in the Eco-indicator 99 method. Changes from the Eco-indicator 99 method are:
• Replacement of the static hazard unit increase with a time integrated function to better describe the time dependant exposure from offshore discharges.
• Replacement of the static total marine volume with the time integrated volume.
The resulting dynamic marine exposure PAF (dme-PAF) is compatible with the ecotoxicity characterization factors in Eco-indicator 99. It is proposed to omit the acute period in the time integrals and only assess the chronic exposure period beginning from day four.
The Dose-related risk and effect assessment model (DREAM) is used to simulate the time variation of offshore discharges. DREAM is used today by Statoil in environmental risk assessments of such discharges. The model is not a multi-media fate model although it includes most of the processes that are part of the EUSES/SimpleBox model. DREAM produces time dependant profiles of discharges. These are used to calculate the time integrals in the dme-PAF method.
Simulations were performed to calculate ecotoxicity characterization factors for glutaraldehyde with the dme-PAF method. The simulations performed show that one of the settings in DREAM will have great influence on the resulting characterization factors, namely the lower concentration limit (LCL). DREAM calculates concentration in cells, and this data is stored and can be extracted in text format. Cells with concentrations below LCL will not be stored and the volume of these cells will be neglected. In order to be able to calculate dme-PAF properly LCL should be set at zero. This will maximize the number of recorded cells. Given the limitations of MS Office Excel other software must be sought to accommodate calculation of dme-PAF.
Dme-PAF will be affected by changes of the mass, concentration or period of the discharge. Ecotoxicity factors therefore should be calculated for different scenarios regarding the location, concentration, mass and period of the discharge.
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Bisinella, de faria Ana barbara. "Development of an integrated approach for wastewater treatment plant optimization based on dynamic modelling and environmental assessment." Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0039/document.
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Les stations d’épuration se tournent actuellement vers des installations de récupération d'énergie et des nutriments. Dans le même temps, elles sont soumises à une réglementation de plus en plus stricte en ce qui concerne l'environnement et la santé humaine. Face au défi ambitieux de réduire les coûts d'exploitation et les impacts environnementaux tout en garantissant la robustesse du procédé, il est nécessaire de développer des outils capables de fournir une évaluation intégrée du procédé. L’objectif de ce travail est de développer une plateforme réaliste et prédictive contenant trois aspects: la modélisation rigoureuse et dynamique de l’ensemble de la station d’épuration; l'analyse de cycle de vie aux frontières étendues pour l'évaluation des scénarios et enfin un outil d'optimisation multi-objectif efficace. La plateforme développée pour l'évaluation environnementale couplée à la modélisation dynamique a d'abord été appliquée à plusieurs cas d’étude. Ainsi des résultats de performance et d’impacts environnementaux ont été obtenus pour la séparation de l’urine à la source, la décantation primaire avancée et le traitement de l'urine par nitritation/ oxydation anaérobie de l’ammonium, et d’autres filières. Compte tenu des importants avantages de la séparation de l’urine établis par les résultats précédents, un générateur d’influents phénoménologique, flexible et dynamique a été adapté afin de fournir des données dynamiques réalistes concernant les flux d'urine et des eaux usées dans les différents scénarios de rétention d'urine. Enfin, comme la combinaison complexe de processus biologiques, chimiques et physiques conduit à un problème lourd en calcul, une étude de faisabilité (temps de calcul et fiabilité) a été réalisée sur l'optimisation multi-objectif. L'obtention d'un ensemble de solutions qui évite toute discrimination préalable entre les coûts, l'environnement et les performances ont permis la discussion des enjeux impliqués. Finalement, la plateforme complète a été appliquée à plusieurs cas d’étude et clarifie les aspects opérationnels des options plus durables en matière de gestion et de traitement des eaux uséesWastewater treatment plants are moving towards energy and nutrients recovery facilities. Simultaneously, they are submitted to stricter regulation with respect to environment and human health. Facing the great challenge of reducing operational costs along with the reduction of environmental impacts and the guaranty of plants robustness, tools might be developed in order to provide an integrated assessment. The goal of this work is to develop a reliable and predictive framework containing rigorous dynamic wide-plant modelling, extended boundaries life cycle assessment for scenarios evaluation and an efficient multi-objective optimization tool. The developed framework for environmental evaluation coupled to dynamic modelling was initially applied to several case studies including urine source separation, enhanced primary clarification and urine treatment by nitritation/ anaerobic ammonium oxidation, offering both performance results and environmental hotspots. Given the important benefits of the urine source separation provided by the previous results, a flexible and dynamic phenomenological influent generator was adapted in order to provide realistic dynamic data concerning urine and wastewater streams in different urine retention scenarios. Finally, as the complex combination of biological, chemical and physical processes leads to a computational expensive problem, a feasibility study (computational time and reliability) on the multi-objective optimization was conducted. Obtaining a set of solutions that avoids any prior discrimination among costs, environment and performance allowed thus the discussion of the involved trade-offs. Finally, the complete framework was applied to several case studies lightening on operational aspects of more sustainable options on wastewater management and treatment
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Purushotham, Vineeth. "Dynamic Life Cycle Costing." Thesis, KTH, Industriell produktion, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102785.
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Maintenance is an extremely important issue in the industry. Testimony to this fact is that European companies spend about 140 billion euro per year on maintenance activities. In Sweden alone, the annual cost of maintenance and related activities reaches 250 billion crowns and these costs are the costs incurred when maintenance jobs are performed and does not include the consequences of poor maintenance with which the costs would be significantly higher. The new paradigm in the manufacturing sector identifies utilization of production resources as a main competitive weapon. To meet the high demands of the industry like high efficiency, enhanced customization and high speed of delivery, a much higher operational availability and capability of production systems have to be achieved. In this context, maintenance becomes an important strategic issue. The objectives of this study are to develop a dynamic LCC model supporting decision making in the early stages of investment and production development process allowing estimating and optimizing life cycle costs of production equipment including maintenance considerations. It will give the concerned stakeholders a better chance of estimating the whole life cycle costs and select proper design alternative for new investments. It can be used as a tool for the justification of investment in Condition Based Maintenance technologies which is underestimated in present calculation models.
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Laratte, Bertrand. "Evaluation dynamique et cumulative des impacts environnementaux dans le cadre d'une analyse de cycle de vie." Thesis, Troyes, 2013. http://www.theses.fr/2013TROY0033/document.
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Les méthodes d’évaluation environnementale sont de plus en plus utilisées pour mieux apprécier les impacts environnementaux générés par les activités humaines (produits, services, systèmes). L’analyse de cycle de vie (ACV) est sans doute la méthode d’évaluation la plus répandue. Elle est aussi souvent considérée comme la plus avancée, bien qu’elle comporte de sérieuses limites (elle n’intègre pas de réels indicateurs économiques ou sociaux, par exemple). Dans cette thèse de doctorat, j’examine plus particulièrement la problématique de l’intégration du temps dans les modèles d’inventaire et les calculs d’impact tout au long du cycle de vie. J’y présente une évolution de la méthodologie d’ACV traditionnelle pour le cas du réchauffement climatique, qui incorpore des aspects dynamiques et cumulatifs exprimés directement en équivalent-CO2. Cette perspective orientée vers une meilleure prise en compte dans les pratiques de reporting et/ou les politiques publiques est ensuite déclinée sur trois cas d’application de complexité croissante pour l’analyse. L’hypothèse centrale de ce travail est que le passage d’une ACV traditionnelle à une ACV dite « dynamique » permettrait d’obtenir des résultats d’évaluation d’impacts plus proches de la réalité des phénomènes environnementauxEnvironmental impact assessment methods are now widely used in order to measure environmental impacts associated with human activities (for products, services, and systems). Life-cycle assessment (LCA) is without doubt the foremost assessment method. LCA is also often thought of as the more advanced one, despite serious limitations (e.g. LCA does not include properly economical or social dimensions). In this PhD report, I explore more specifically the issue of integrating time in both inventory models and impact assessments along the life-cycle. In the case of climate change, I offer an evolution of traditional LCA towards a framework that includes dynamic and cumulative aspects as expressed directly in CO2-equivalent. This approach, which is oriented towards reporting practices and/or public policies, is afterwards applied to three different case studies of growing complexity. The central hypothesis of this work is that switching from traditional to so-called “dynamic” LCA would allow for better results with regards to one reality of environmental processes
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Emblemsvåg, Jan. "Activity-based life-cycle assessments in design and management." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/32855.
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Demou, Evangelia. "Nanoparticles and solvents : exposure, risk and life-cycle-assessments in occupational settings /." [S.l.] : [s.n.], 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18189.
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Fichana, Daniel. "Green engineering and gate-to gate life cycle assessments for pharmaceutical products /." Full text available online, 2005. http://www.lib.rowan.edu/find/theses.
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Moraga, Gustavo Longaray. "Avaliação do ciclo de vida e simulação termoenergética em unidade habitacional unifamiliar do Programa Minha Casa Minha Vida." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/169822.
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Os edifícios são responsáveis por importantes impactos ambientais, principalmente, pelo seu longo ciclo de vida. Neste sentido, as edificações são potenciais redutoras de danos ambientais, já que as decisões sobre seu impacto podem ser feitas em projeto. No Brasil, o Programa Minha Casa Minha Vida (PMCMV) produziu mais de dois milhões de unidades de habitação, sendo um importante gerador de impactos. Foram realizadas pesquisas avaliando impactos sociais, urbanísticos e arquitetônicos do PMCMV, entretanto ainda existe escassez de estudos avaliando os impactos ambientais dessas edificações. Esta pesquisa utiliza a metodologia de Avaliação do Ciclo de Vida (ACV) para quantificar os impactos ambientais potenciais de uma casa do PMCMV. A metodologia considera três fases, com referência no estudo de caso de uma casa térrea situada na região metropolitana de Porto Alegre (sul do Brasil). A Fase 1 quantifica o uso de energia através de simulação termoenergética, testando envoltórias alternativas em comparação à original. A Fase 2 realiza a ACV preliminar, para verificar as contribuições de impacto mais relevantes em dois modelos selecionados. A Fase 3 desenvolve a ACV final com dados adaptados para a realidade brasileira. Os resultados demonstram que os impactos operacionais da edificação são os mais importantes ao longo do ciclo de vida de 50 anos, para as duas alternativas de envoltória avaliadas. Mesmo assim, os requerimentos incorporados da edificação podem representar impactos importantes, ultrapassando 40% em categorias como aquecimento global e depleção da camada de ozônio. O transporte de materiais de construção e matérias primas é um dos maiores causadores dos impactos incorporados. Além desse, a recorrência de manutenções mostra-se importante, assim como a durabilidade dos materiais de construção. A aplicação da ferramenta de ACV confirma sua importância como instrumento para a tomada de decisão, identificando processos mais relevantes na qualificação ambiental de edificações.Buildings are responsible for expressive environmental impacts, especially for its long life-cycle. In fact, buildings are important potential reducers of environmental damages, because decisions concerning its future impacts can be made at design stage. In Brazil, “My House My Life” program (MHMLP) produced more than two million dwellings, generating significant impacts. Some of MHMLP impacts were already addressed, such as social, urban and architectural, however there is a lack on environmental impacts studies focused on these buildings. This research applies Life Cycle Assessment method to quantify potential environmental impacts of a MHMLP dwelling. Methodology considered three phases, using as reference the case study of a single-story house located at the metropolitan area of Porto Alegre (southern Brazil). Phase 1 quantifies energy use through thermal dynamic simulations, considering different encloses types in comparison to the original option. Phase 2 applies streamlined Life Cycle Assessment (LCA) framework to evaluate the most important contributions to the environmental impacts of the two previously selected models. In phase 3, LCA was developed considering data regionalization and adaptation to the Brazilian context. Results show that operational impacts are the most important ones on the 50 years dwelling life cycle, for both evaluated alternatives. Nevertheless, embodied impacts can represent more than 40% of total global warming and ozone depletion potential impacts. Transportation of raw and construction materials is one of the most important contributors to embodied impacts. Furthermore, recurrent embodied impacts are important, as well as construction materials durability. LCA application validates its importance as a framework to support decision-making, identifying hotspots on buildings environmental qualification.
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Chen, Chialin. "Prospects fro automobile recycling, an integrated approach of systems dynamics and life-cycle assessment." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/35426.
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Louis, J. N. (Jean-Nicolas). "Dynamic environmental indicators for smart homes:assessing the role of home energy management systems in achieving decarbonisation goals in the residential sector." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526214535.
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Abstract Achieving the objective of a decarbonised economy by 2050 will require massive efforts in the energy sector. Emissions from residential houses will have to be almost completely cut, by around 90% by 2050. Home automation is a potential tool for achieving this goal. However, the environmental and economic benefits of automation technologies first need to be assessed. This thesis evaluates the impact of home automation for electricity management in the residential sector using environmental and economic indicators. To this end, a life cycle assessment was performed to evaluate the impacts of the manufacturing, use and disposal phases. The influences of end-user behaviour, household size and multiple levels of technological deployment were also investigated. A Markov chain simulation tool, built on the MatLab platform, was developed to assess all possible combinations of impacting factors. Dynamic environmental indicators were developed based on the ReCiPe method for aggregating the impacts of processes. All these indicators were then combined to form a single index based on multi-criteria acceptability analysis. The results suggest that home automation can decrease peak load, but that overall electricity consumption may increase due to electricity use by the actual automation system. The effect of home automation was more noticeable in larger households than in one-person households. In addition, use of dynamic environmental indicators proved more relevant than fixed indicators to represent the environmental impact of home automation. Within the life cycle of automation technology, the manufacturing phase had the highest impact, but most of the CO2 emissions originated from the use phase. In conclusion, the most important environmental benefit of home automation is reducing CO2 emissions during peak time by load shiftingTiivistelmä Vähähiilisen talouden saavuttaminen vuoteen 2050 mennessä edellyttää valtavia ponnisteluja energia-alalla. Rakennuksista aiheutuvia päästöjä on vähennettävä radikaalisti, jopa 90 % vuoteen 2050 mennessä. Rakennusten energiatehokkuutta edistävä automaatiotekniikka on yksi keino tämän päämäärän saavuttamiseen. Kotiautomaation kautta voidaan sekä vähentää energian kokonaiskulutusta että tasoittaa energiankäyttöprofiilia. On kuitenkin tutkittava myös, mitkä ovat automaatiotekniikan ympäristö- ja taloudelliset vaikutukset. Tässä työssä käsitellään kotiautomaation vaikutusta sähkön kulutuksen hallintaan asuinrakennuksissa käyttämällä ympäristö- ja talousindikaattoreita. Tätä varten suoritettiin kotiautomaation elinkaariarviointi selvittämällä laitteiden valmistus-, käyttö- ja hävittämisvaiheiden ympäristövaikutukset. Työssä tarkasteltiin myös asukkaiden käyttäytymisen, kotitalouden koon ja eri teknologiavaihtoehtojen vaikutuksia ympäristö- ja talousvaikutuksiin. Arviointi suoritettiin Markovin ketjun simulointityökalulla, joka rakennettiin Matlab-alustalle. Dynaamisia ympäristömittareita kehitettiin ReCiPe-menetelmää käyttäen. Indikaattorit on edelleen yhdistetty yhdeksi indeksiksi käyttäen monikriteeriarviointia. Tulokset viittaavat siihen, että huippukuormitusta voidaan vähentää käyttämällä kotiautomaatiota, mutta sähkön kokonaiskulutus voi kasvaa automaatiojärjestelmän sähkönkulutuksen takia. Kotiautomaation vaikutukset ovat eniten havaittavissa suurissa kotitalouksissa. Lisäksi, dynaamiset indikaattorit edustavat paremmin kotiautomaation vaikutusta ympäristöön kuin staattiset indikaattorit. Automaatioteknologian elinkaaressa suurimmat ympäristövaikutukset ovat valmistusvaiheessa, mutta CO2-päästöjä syntyy eniten käyttövaiheessa. Lopuksi voidaan todeta, että kotiautomaation merkittävin ympäristöhyöty on CO2-päästöjen vähentäminen huippukulutuksen aikana siirtämällä kuormitusta toiseen ajankohtaan
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Andersson, Jenny. "Environmental Impacts of Contaminated Site Remediation : a Comparision of two Life Cycle Assessments." Thesis, Linköping University, Department of Thematic Studies, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1931.
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The decision process of which technique to choose for remediation of contaminated sites has traditionally focused on the clean up level, the time required and the economical resources. The environmental costs of the remediation are seldom taken into consideration. With a Life Cycle Assessment (LCA) it is possible to receive an overall picture of the environmental impacts caused by a remediation technique. In this thesis a comparison of two LCA methods has been made. The methods are named REC and Uva and are used in the Netherlands and Germany. Two remediation techniques, the adsorption technique and the bioremediation technique, were compared and data from a discontinued petrol station were used. The output from the REC method indicated that the adsorption technique causes more environmental costs then the bioremediation technique. The main reason is because the adsorption technique consumes more groundwater and energy. The UvA method presented a different result. According to this method the bioremediation technique causes more environmental costs. This is because the bioremediation technique consumes more energy and causes more emissions. The main reasons of the difference between the REC and the UvA methods are that they use diverse ways to calculate the consumption of energy, have different system boundaries and consider different impact categories. A conclusion of the present study is that a decision process of which remediation technique to use at a contaminated site could be dependent on which method is used as a decision support tool.
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Lökholm, Alvestad Ragnvald. "Life Cycle Assessments as a front-end Systems Engineering tool in ship design." Thesis, KTH, Marina system, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102049.
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Environmental impact analyses have not been popular in ship design due to the complexity of both the analysis itself and the ship system. This study proposes a framework for life cycle assessments (LCA) for ship design, using a foundation in systems engineering to position the assessment method in the design process. By limiting the analysis to comparing the differences between design alternatives and accepting lower result precision, the effort and level of expertise required is significantly reduced. Reducing the requirement on precision allows for approximate input data as well, enabling the naval architect to use simple methods, e.g. the Holtrop-Mennen method, to provide input data. Despite this imprecision, it is shown that one can observe trends in the result that point toward a design concept with lower impact than its contestors. Further, one must select an evaluation model and database, both determined by experts, that support the analysis well, and a software to present the naval architect with an interface with which he can easily interact. The benefits of such simplified analyses are that little LCA expertise is required, only a few parameters must be modelled and most of the input data is determined, allbeit approximately, through the initial regular ship design process and is readily available. The pitfalls are a low degree of transparency due to the evaluation model and risk for misinterpretation and misuse of the results because of the limit on modelled parameters and assessment precision. Using this framework, with its limitations, lowers the threshold to implementing an LCA as a design review tool in early design stages, a front-end tool, allowing the environmental assessment to affect earlier design decisions in a greater extent than today.
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Alcaraz, Ochoa Maria de Lourdes. "Development of metrics for streamlined life cycle assessments : a case study on tablets." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107098.
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Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 59-63).
Growing concern about climate change and human impact on the environment have resulted in an increase in interest for evaluating the environmental impact of products and services we consume. Life cycle assessment (LCA) has become the most prominent method for environmental evaluation. Life cycle assessment is the quantification of the environmental impacts of a product or service through its whole life cycle, from the extraction of materials to manufacturing and end of life. A carbon footprint is a subset of an LCA. LCAs are required as part of government regulations, used by companies to identify high resource use in their supply chain or to choose between product designs and by consumers to choose between alternative product choices. LCAs provide valuable information; however, they are resource intensive, time consuming and uncertain. Therefore, a methodology that addresses all these issues is needed. This study addresses the following question: Can LCAs be streamlined while still providing useful information? To answer this, an under-specification, probabilistic screening methodology is employed. The screening methodology uses a high level assessment of the footprint, incorporates uncertainty in the inputs, and refines data around the primary drivers of impact. The streamlined LCA procedure is extended to include a Sobol based sensitivity analysis methodology for identifying high impact activities. The effects of partial perfect information in subsequent data acquisition activities on the streamlining methodology are examined. Metrics to determine sufficiency in the data gathering procedure and to determine whether decision makers can sufficiently distinguish between two products or design alternatives are developed. A procedure to quantify the cost of additional information is developed. Finally, an exploration of the scenario space of the impacts is analyzed. The extended streamlined methodology is applied to a case study on tablets, with a focus on integrated circuits. This thesis finds that the streamlined, probabilistic methodology can be used to cost-effectively evaluate the environmental impact of products while still taking uncertainty into account. Metrics to determine sufficiency can be effectively used, and the presence of partial information does not limit the usefulness of the metrics. Furthermore, quantifying the cost of additional information can help determine sufficiency in data collection efforts and can help understand the challenges that companies face when performing an LCA.
by Maria de Lourdes Alcaraz Ochoa.
S.M. in Technology and Policy
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Green, Lilian. "Dynamic simulation for whole life appraisal." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325206.
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Kim, Sangho. "Comparative Life Cycle Assessments of Conventional Products and 3D-Printed Wood-Plastic Composite Alternatives." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-287737.
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As additive manufacturing gains market potential as a mainstream process in various sectors of industry, there is a growing need for addressing environmental aspects of this technology and the materials associated with it. In this master thesis, comparative life cycle assessments (LCAs) from cradle to grave between the conventional products and 3D-printed alternatives made of wood-plastic composite (WPC) were conducted based on the ISO 14044:2006 standard. Environmental impacts of each product were quantified for 10 impact categories. The goal of the LCAs was to determine whether the use of the 3D-printed WPC products may suggest a sustainable alternative to the conventional ones. This master thesis presents three case studies in which comparative LCAs were carried out. The first two case studies are about storage compartments for trucks from Scania, and the third one is about ceiling boards from Veidekke. The results showed that, in all case studies, the 3D-printed WPC alternatives would have smaller environmental impacts compared with the conventional products. The most significant difference was observed in the first two case studies because of the light- weighting effect. The alternatives showed 51%, 68% and 13% lower global warming potential (GWP) than the conventional products in each case study, respectively. However, the results of the cradle-to-gate LCAs suggested that the 3D-printed WPC alternative might cause greater environmental impact than the conventional products regarding some impact categories. Therefore, in the LCA context, the 3D-printed WPC alternatives would be much more beneficial to the environment compared with the conventional products, but theenvironmental benefits might be insignificant from the manufacturer’s perspective.Eftersom additive tillverkningsteknik ökar marknadspotentialen som en vanlig process inom olika industrisektorer, finns det ett växande behov av att ta itu med miljöaspekterna av denna teknik och de material som är associerade med den. I detta examensarbete avhandling genomfördes jämförande livscykelanalys (LCA) från vagga till grav mellan de konventionella produkterna och 3D-printade alternativ av träplastkomposit (WPC) baserat på ISO 14044: 2006-standarden. Miljöpåverkan av varje produkt kvantifierades för 10 miljöeffekter. Målet med LCA var att avgöra om användningen av de 3D-printade WPC-produkterna kan vara ett hållbart alternativ till de konventionella. Denna avhandling presenterar tre fallstudier där jämförande LCA utfördes. De två första fallstudierna handlar om förvaringsutrymmen för lastbilar från Scania, och den tredje om takskivor från Veidekke. Resultaten visade att de 3D- printade WPC- alternativen i alla fallstudier skulle ha mindre miljöpåverkan jämfört med konventionella produkter. Den mest signifikanta skillnaden observerades i de två första fallstudierna på grund av den lägre vikte viktningseffekten. Alternativen visade 51%, 68% och 13% lägre global uppvärmningspotential (GWP) än de konventionella produkterna i respektive fallstudie. Emellertid föreslog resultaten av vaggan-till-grind-LCA att det 3D-printade WPC-alternativet kan orsaka större miljöpåverkan än de konventionella produkterna avseende vissa miljöeffekter. Därför, i LCA-sammanhang, skulle de 3D-printade WPC-alternativen vara mycket mer fördelaktiga för miljön jämfört med konventionella produkter, men miljöfördelarna kan vara obetydliga ur tillverkarens perspektiv.
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Balogun, T. B. "Integrating bridge maintenance life cycle assessments into bridge design for improved sustainable decision making." Thesis, University of the West of England, Bristol, 2018. http://eprints.uwe.ac.uk/33148/.
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Environmental sustainability issues are being considered across many construction sectors, emerging from global concerns on resource depletion and CO2 emissions. Whilst construction sectors are minimising the environmental impact of their activities and the associated CO2 and GHG emissions, not many of these environmental issues are factored into the early design stage of bridges to facilitate design choices. Consequently, environmental impacts of bridge maintenance activities are not factored into the bridge design process. Doing so can potentially reveal the overall environmental performance of the bridge and enhance design choices. The LCA environmental tool is gaining ground across many construction sectors, because of its capacity to reveal the environmental impacts of process and services. LCA has been only minimally explored for bridges, and its integration into the early design process has not been seriously attempted. In fact, only a small volume of literature has considered LCA application to bridge maintenance activities, and that without considering the scope for influencing sustainable bridge design decisions through stakeholders’ input. The research was undertaken to provide insights and recommendations for incorporating LCA result of bridge maintenance methods at the early design stage to aid sustainable design choices. The study employed an explanatory mixed-method approach. The study conducted a thorough literature review to understand and explore the environmental aspect of sustainability in bridges and the trend and usefulness of LCA results in the bridge industry. Results revealed that not many environmental matters are considered for bridge design and maintenance, and that LCA application for bridges is limited to comparison of materials, components and structural types. As such, this study launches an LCA analysis of some major maintenance activities of concrete, steel, and masonry bridge, which is mainly assumed for other studies. Data required for the LCA analysis was derived from secondary sources (that is, literature) and verified by industry experts through an online survey. Purposive sampling strategy was employed in selecting relevant experts. Verified data were combined with primary data obtained in the SimaPro database used to conduct the LCA analysis. Results revealed expansion joint and bearing replacement as key sources for high environment impact in concrete and steel bridge, whereas saddling rehabilitation had the most impact for masonry bridge. The overall comparison revealed masonry bridge as the least environmentally impactful bridge on account of the selected maintenance actions. Through a semi-structured interview, the study presented the derived result to bridge design experts to verify and reveal the usefulness of the result. Experts revealed the emergence of masonry bridge (as the least impactful structure) as the major usefulness of the result. Any industry drive towards masonry bridges is, however, constrained by initial construction cost, span limitation and speed of completion. General findings from the study revealed that LCA incorporation into the design process will be a complex matter, as the design process is already intricate, and environmental concerns are not a major design criterion. The study therefore makes recommendations that can enhance the consideration of LCA, and consequently LCA of bridge maintenance actions, in the early design process. The thesis concludes by making detailed recommendations to policy makers, researchers, designers, and bridge owners.
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Biewald, Anne. "A dynamic life cycle model for Germany with unemployment uncertainty." Phd thesis, Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2009/3311/.
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This work analyzes the saving and consumption behavior of agents faced with the possibility of unemployment in a dynamic and stochastic life cycle model. The intertemporal optimization is based on Dynamic Programming with a backward recursion algorithm.
The implemented uncertainty is not based on income shocks as it is done in traditional life cycle models but uses Markov probabilities where the probability for the next employment status of the agent depends on the current status. The utility function used is a CRRA function (constant relative risk aversion), combined with a CES function (constant elasticity of substitution) and has several consumption goods, a subsistence level, money and a bequest function.Diese Arbeit modelliert das Spar- und Konsumverhalten von Individuen in Deutschland mit einem Lebenszyklusmodell. Dabei hat das Modell zwei Besonderheiten, erstens trifft die Möglichkeit arbeitslos zu werden nicht jeden Agenten des Models mit der gleichen Wahrscheinlichkeit, sondern wird von Bildungsabschluss und dem Beschäftigungsstatus des Agenten beeinflußt und zweitens weicht die verwendete Nutzenfunktion von den Standardnutzenfunktionen ab und implementiert Vererbung, Geld, verschiedene Güter und Subsistenzlevel. Der Optimierungsalgorithmus basiert auf Dynamischer Programmierung.
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Schau, Erwin Andreas Meissner. "Environmental life cycle assessments of fish food products with emphasis on the fish catch process." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for industriell økonomi og teknologiledelse, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15440.
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Sustainable development embraces economics, society and nature and is the global context for this PhD-thesis. Modern fishery is dependent on fossil fuels, which use is the antithesis of sustainable fishery. Environmental degradation is closely related to health aspects, which are increasingly important to consumers and other stakeholders. For the fish food product (FFP), the main focus of prior research has been on threatened stock populations. Less attention has been focused on environmental problems related to the use of energy and material, not only by the fishing vessel, but for the whole life cycle of the FFP. This PhDproject is a contribution to closing this gap. The overall goal of the research behind this thesis is to demonstrate a methodology for systematic environmental life cycle assessments (LCA) of FFP with an emphasis on fishery. LCA has been developed for commodity products and this work contributes to expanding the application to food products. LCA is the basis for creating an environmental product declaration (EPD) by following the product category rules (PCR). Systems engineering principles and processes provide the tools to systematize the analysis of the life cycle of the FFP, by modelling the fish food production systems. Systems engineering with input from LCA, stakeholder analysis and eco-labelling is used to develop a methodology presented as a framework for environmental analysis of the FFP. Three studies are combined into a single case study resulting in an LCA of fish products that has been used to develop an EPD for Atlantic herring (Clupea harengus) based on the PCR developed for wild caught fish. Environmental performance indicators relevant for FFP have been explored and a number of parameters are recommended for use in communicating the environmental impact of a FFP. Greatest attention has been on the fishing vessels because their energy consumption accounts for the largest environmental impacts of the FFP. The research results contribute to better transparency about the environmental impact of the life cycle of FFP and thereby support more sustainable decision-making in the fishery sector. In the future, the framework developed for environmental life cycle assessment of FFPs, could be expanded to other food products and so be used to compare different food products against each other.En bærekraftig utvikling omfatter økonomi, samfunn og natur og er utgangspunktet for denne doktorgradsavhandlingen. Dagens fiskerier er avhenging av fossile energikilder, noe som skaper vansker for en bærekraftig utvikling. Miljøproblemer er nært beslektet med helseproblemer, som blir viktigere og viktigere for forbrukere og andre interessenter. Hovedfokuset innenfor forskning på fisk har vært på hvordan overfiske kan unngås. Andre miljøproblemer, slik som klimaendringer, forurensning av vann og luft som et resultat av energi- og materialbruk har vært lavere prioritert. Dette gjelder ikke bare for fiskebåten, men hele livsløpet til fiskematproduktet, fra bunn til bord. Dette doktorgradsprosjektet er et bidrag til å rette opp denne skjevheten. Hovedmålet med forskningen bak denne doktorgradsavhandlingen er å demonstrere en metodikk for systematiske livsløpsanalyser (LCA) av fiskematprodukter, med hovedvekt på fisket. Prinsipper og prosesser fra systemteknikk kan benyttes i analyser av miljøproblemer. Denne forskningen er den første til å benytte seg av systemteknikk for å analysere miljøproblemer i tilknytning til fiskematproduktet. Livsløpstenkning er en helhetlig tilnærming og gjør at forskyvning av miljøproblemer fra en fase til en annen i livsløpet blir synlig. LCA har blitt utviklet for vareproduserende industri. Denne forskningen er et bidrag til å anvende LCA også for matproduksjon, med større komplekse systemer som verdikjeder for fisk der fiskebåten og fangstmetodikk utgjør en vesentlig del av miljøprestasjonene. LCA danner grunnlaget for å utarbeide miljødeklarasjoner, kalt EPD, hvis retningslinjer er fastsatt i produktkategorireglene, såkalte PCR. Systemteknikk i kombinasjon med LCA, interessentanalyse og EPD blir brukt til å utvikle et rammeverk for miljøanalyser av fiskeproduktets livsløp. Et sett av forskjellige studier, sammensatt til et case-studie, har resultert i en LCA av fiskeprodukter som har blitt brukt til å utvikle en EPD for sild (Clupea harengus) basert på PCRen utviklet for villfanget fisk. Miljøprestasjonsindikatorer relevante for fiskematprodukter er blitt undersøkt og et utvalg har blitt foreslått for bruk i kommunikasjon av miljøpåvirkning fra fiskematprodukter. Størst fokus har vært på fiskebåten, da særlig dennes energiforbruk bidrar til den største miljøpåvirkningen. Forskningsresultatene bidrar til økt transparens hva gjelder miljøbelastningen fra fiskeprodukter og er dermed et bidrag til å drive utviklingen i fiskerisektoren i en bærekraftig retning. Videre utvikling kan være å utvide rammeverket for fiskematprodukter til også å omfatte flere matprodukter, slik at disse kan sammenlignes.
Nachhaltige Entwicklung beinhaltet Ökonomie, Gesellschaft und Natur und ist der Ausgangspunkt dieser Dissertation. Moderne Fischerei ist von fossilen Energiequellen abhängig, was Schwierigkeiten für eine nachhaltige Entwicklung bereitet. Umweltprobleme sind stark mit gesundheitlichen Problemen verbunden, welche immer größere Bedeutung für Verbraucher und andere Betroffene annehmen. Schwerpunkt der Fischereiforschung war bislang die Überfischung der Fischressourcen. Anderen Umweltproblemen, wie Klimaänderung, Verunreinigung von Luft, Boden und Wasser, resultierend aus Energie- und Materialverbrauch wurde bisher weniger Beachtung geschenkt. Das gilt nicht nur für den Produktzyklus des Fischfangschiffs, sondern auch für den ganzen Lebenszyklus des Fischereierzeugnisses, vom Meeresboden auf den Tisch. Diese Dissertation leistet einen Beitrag zum Ausgleich dieses Ungleichgewichts. Das Hauptziel dieser Forschung ist die Demonstration einer Methodik zur systematischen Ökobilanzierung von Fischereierzeugnissen, wobei der Schwerpunkt auf dem Fischfangprozess liegt. Prinzipien und Prozesse des Systems Engineering kommen in Analysen von Umweltproblemen zur Anwendung. Diese Forschung ist die erste, die das Systems Engineering verwendet, um Umweltprobleme in Verbindung mit Fischereierzeugnissen zu analysieren. Ökobilanzen sind ein ganzheitlicher Ansatz, um Problemverlagerung zwischen den Lebenszyklusphasen eines Produktes zu erkennen und zu vermeiden. Ökobilanzen wurden ursprünglich für Verbrauchsgüter entwickelt. Diese Forschung leistet einen Beitrag, diesen Ansatz auch auf Lebensmittel mit großen komplexen Systemen wie die Wertkette für Fisch, wo das Fischereischiff und verschiedene Fangtechniken einen wesentlichen Teil der Umweltleistung ausmachen, zu übertragen. Ökobilanzen bilden die Grundlage, um Umweltdeklarationen, deren Regeln und Anforderungen in den Produktkategorieregeln festgelegt sind, zu entwickeln. Systems Engineering in Kombination mit der Ökobilanzmethode, Interessentenanalyse und Umweltdeklarationen wird verwendet, um einen Rahmen für Umweltanalysen der Lebenszyklen von Fischereierzeugnissen zu entwickeln. Resultate einer Kombination unterschiedlicher Studien, zusammengesetzt zu einer Fallstudie, werden benutzt um; Umweltdeklarationen für Hering (Clupea harengus) basierend auf den für wild gefangenen Fisch entwickelten Produktkategorieregeln zu demonstrieren, Umweltleistungsindikatoren mit Relevanz für das Fischereierzeugnis zu untersuchen, und eine Auswahl davon zur Bekanntgabe von Umwelteinwirkung durch Fischereierzeugnisse zu empfehlen. Der Schwerpunkt lag dabei auf dem Fischfangschiff, weil dessen Energieverbrauch die größte Umwelteinwirkung ausmacht. Die Forschungsresultate tragen zur einen höheren Transparenz der Umweltbelastung durch Fischereierzeugnisse bei und führen so die Entwicklung innerhalb der Fischerei in eine nachhaltige Richtung. Künftig könnte die in dieser Dissertation entwickelte Methode zur Untersuchung von Fischereierzeugnissen auf weitere Lebensmittel ausgedehnt werden, so dass ein Vergleich unterschiedlicher Lebensmittel möglich wird.
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Wildnauer, Margaret T. (Margaret Thea). "Evaluation of probabilistic underspecification as a method for incorporating uncertainty into comparative life cycle assessments." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78508.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 97-100).
Life cycle assessments are quickly becoming a crucial method through which the environmental impacts of products or processes are evaluated. A concern with current practice, however, is that the use of deterministic values for inputs and final results only represent a single scenario, not all possible values and outcomes, or even a real-world situation. By incorporating uncertainty, an LCA can account for inherent variation and the use of proxy data, both of which are common occurrences in LCA implementation. In a comparative LCA, this uncertainty allows a decision to be made between alternatives with a certain level of confidence. While uncertainty is necessary for credible results, its implementation can also be time consuming. As LCAs grow more common, methods of streamlining are being explored to reduce both the effort and cost. One such streamlining method that also incorporates uncertainty is probabilistic underspecification. This method evaluates environmental parameters by dividing them into different material and process categories. The lowest level of specification, Level 1, is defined by the type of material or process, such as metal or freight transportation. This category is then subdivided based on different characteristics of the material or process. The highest level of specification, Level 5, consists of the individual database processes used by traditional LCAs. This thesis compares the streamlining method of probabilistic underspecification to the more common method of incorporating uncertainty, termed here as individual probabilistic specification. A case study on alternative pavement designs is used to demonstrate and compare both the methodologies. The effort required for each methodology is compared by the percentage of processes specified at Level 5, which is 100% for individual probabilistic specification, but much less for probabilistic underspecification. The results of the case study showed that as little as 32% or less of the processes need to be specified at Level 5 in order to have the required level of confidence in the decision being made. It can be seen that, as a streamlining method to estimate the results of comparative LCAs, probabilistic underspecification is a viable option.
by Margaret T. Wildnauer.
S.M.
24
Bessou, Cécile. "Greenhouse gas emissions of biofuels: improving Life Cycle Assessments by taking into account local production factors." Phd thesis, AgroParisTech, 2009. http://tel.archives-ouvertes.fr/tel-00453003.
Full textAbstract:
L'Analyse de Cycle de Vie (ACV) permet de comptabiliser les émissions de la production à la combustion d'un biocarburant mais elle ne prend pas en compte la dynamique locale de ces émissions, notamment celle des émissions de N2O, principal gaz à effet de serre agricole. Notre objectif fut d'abord d'analyse l'effet du tassement du sol sur les émissions de N2O en combinant expérimentation et modélisation. À l'aide de chambres automatiques sur des parcelles de betterave, nous avons mesuré en 2007-2008 des émissions cumulées de 944-977 g N-N2O ha-1 en sol non tassé et 1,448-1,382 g N-N2O ha-1 en sol tassé. Les émissions plus importantes sur le tassé furent surtout dues aux conditions anoxiques propices à la dénitrification. Nous avons modifié le modèle NOE pour mieux simuler la nitrification et la variation des fractions de N2O sur les produits totaux. Malgré une meilleure prédiction de la nitrification et des flux post-fertilisation, le modèle modifié NOE2 sous-estima les émissions totales. La sévère sous-estimation en été montre que les cycles sec-humides peuvent entraîner de fortes émissions dont le déterminisme n'est ni élucidé ni modélisé. Nous avons ensuite utilisé un modèle d'agro-écosystème (CERES-EGC-NOE2) pour produire les données d'inventaire pour nos ACV locales. L'éthanol de Miscanthus produit en Picardie entraîne potentiellement beaucoup moins d'impacts environnementaux que celui de betterave. Comparés à l'essence, l'éthanol de Miscanthus permettrait une réduction de gaz à effet de serre de 82-85% par MJ, celui de betterave une réduction de 28-42% par MJ en fonction des conditions pédo-climatiques et des pratiques agricoles locales.
25
Van, der Walt Janette. "The application of life cycle assessments (LCA's) in the chemical industry / by Janette van der Walt." Thesis, Potchefstroom University for Christian Higher Education, 1999. http://hdl.handle.net/10394/64.
Full textAbstract:
The Life Cycle Assessment (LCA) methodology can be applied in various stages -
especially conceptual design and IS0 14001 Environmental Management System
(EMS) implementation - in order to add value and incorporate environmental
concerns in the chemical industry to improve the overall environmental performance.
The LCA methodology was successful in identifying the environmental issues of the
conceptual design case study for future environmental focus in the conceptual
project, taking into accol-~nth e limited detail data available so early in the project life
cycle. The LCA was even more successful in identifying the major environmental
impacts and aspects of different process units relative to each other in the
implementation of an IS0 14001 Environmental Management System due to the
availability of more detail data from actual analyses and measurements. Only
environmental problem identification, focus and priorities are given by the LCA, while
the severity of the potential impacts is not determined.Thesis (MSc)--PU for CHE, 1999.
26
de, Kock Lorren. "Carbon intensive but decarbonising quickly? Retrospective and prospective life cycle assessments of South African pome fruit." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29886.
Full textAbstract:
The South African economy has in the past been categorised as carbon intensive due to an energy and capital intensive development path and an associated set of economic activities termed the minerals-energy complex. International export markets, specifically the European Union (EU), are systematically applying pressure on imported products with a high carbon footprint through potential trade barriers, border tariffs and consumer lobbying. The objective of this research is to determine whether South African pome fruit has a higher global warming potential (GWP) per kg fruit compared to pome fruit cultivated and packaged in other countries. Following on from this finding, is to determine whether the Greenhouse Gas (GHG) emissions for pome fruit in South Africa are declining, ,as could be expected based upon the declining carbon intensity of the South African economy since 1990 and efficiency improvements in the industry itself. The Attributional Life Cycle Assessment (ALCA) methodology is used to determine the Global Warming Potential (GWP) per kg fruit for multiple boundaries within the value chain, retrospectively for the years 2000, 2010 and prospectively for 2020. The product system boundary includes the farm, packhouse, controlled atmosphere store (CA) and cold store (CS). For the Life Cycle Inventory (LCI), the temporal variations in pome fruit cultivation, packing and storing for the export and local market are taken into account for each of the years studied. Using the single issue characterisation methods – the GHG Protocol and the IPCC GWP 2013 100a – the results for each of the years under study are compared at a value chain, boundary and activity level. The results indicate that the baseline GWP result for South African pome fruit in the year 2000 was relatively high compared to similar international LCA research on apples and pears during this period. However, the results for the years 2010 and 2020 clearly indicate a sustained decline in relative GHG emissions of South African pome fruit according to the GWP indicator result per kg fruit and the normalised results for the industry. It is clear that there has been an increase in eco-efficiency in a number of farming and agro-processing practices since 2000 which correlates to the declining CO2e emissions in the boundaries and value chain of South African pome fruit. The carbon intensity and efficiency of the pome fruit value chain is also determined for each year using the kg CO2e per kg fruit and the industry revenue for a specific year (ZAR 2010 adjusted for PPI). The findings support the hypothesis that the carbon intensity of the pome fruit industry has indeed declined since the year 2000. This decline in carbon intensity represents a relative decoupling of CO2e emissions from economic growth of the industry from 2000 to 2020.
27
Chaudhary, Osman, and Erdem Yüksek. "Dynamic life-cycle costing in asset management of production equipments with emphasis om maintenance." Thesis, KTH, Industriell produktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-41281.
Full textAbstract:
In the contemporary industry, companies need to make investments to grow their business volume. However each investment comes with its own risk. Cost of an equipment does not only consist of the initial payment but also covers the future costs related to the operations, maintenance, quality of production and many other associated issues. Therefore, economical analysis of an asset should be done by considering the whole life cycle. Life-Cycle Costing (LCC) can be used as an engineering tool in order to assess the future business risks and prevent the unexpected costs and losses due to failures and downtime before they occur. When first proposed as a proactive effort, LCC came into the industry with several advantages to be provided. However it could not keep pace with the modern industrial IT development.Automated machine tools constitute a crucial part of modern manufacturing activities. As an asset within the production layout, life-cycle of machine tools consists of several periods which are basically early design, purchase, installation, operation and disposal stages. Unfortunately, lack of a detailed cost analysis method drives most of the manufacturers to follow minimum adequate design (MAD) principle. As described above, decision process of investing in new equipments brings along the old famous debate: “Short-term spending or long-term benefits?”Recent studies have proven the fact that interruptions in production due to failures and maintenance account for a considerable part of not only production profit losses but also overhead costs. Regarding this problem, several new concepts in maintenance such as Reliability Centered Maintenance (RCM) and Condition Based Monitoring (CBM) have been developed. Main goal of these methods is to anticipate the failures which are likely to occur and keep the continuity of production. However, usage of these methods is still at very limited level since industry lacks a dynamic costing method that can justify the initial investment in production equipment assisted by such maintenance techniques. Although they are effective to some extent in calculating direct costs, traditional cost analysis methods usually fail in providing an accurate view on the indirect, consequential and overhead costs. On the other hand, by its2different point of view in handling indirect costs and their future impacts, LCC method can be a possible solution for this investment analysis problem.The objective of this study is to develop an LCC model that can assist the decision making process during the early stages of an investment. A dynamic LCC model which considers the maintenance aspect will be proposed and, as a specific case, this model will be used for estimating and optimizing the life-cycle costs of a CNC machining center based on its real-time technical data history.
28
Pinilla, Maria Juliana. "Comparative Life Cycle Assessments of Lignocellulosic and Algae Biomass Conversion to Various Energy Products through Different Pathways." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3740.
Full textAbstract:
Bioenergy has the potential to reduce the world's dependence on fossil fuels, and to decrease the CO2 emissions due to fossil combustion. Lignocellulosic and algae biomass have been presented as promising feedstocks for bioenergy production.
In this study, a comparative Life Cycle Assessment (LCA) has been developed to evaluate the environmental impacts associated with different energy products via different routes across the whole life of algal and lignocellulosic bioenergy. Results were compared per energy basis, the production of 1 million BTU of energy products.
For the development of the comparative algae biomass conversion LCA, algal biomass was converted to liquid biofuels via a thermochemical gasification and Fisher-Tropsch Synthesis (FTS) process; and to electricity and heat via anaerobic digestion and combined heat and power (CHP) process. Overall results from the algae biomass conversion LCA showed that the process that converts algae biomass through anaerobic digestion and CHP process to electricity and heat had the highest overall environmental impact. Results also showed that the impact categories that appear to contribute the most to the overall impacts are ecotoxicity, human health non-cancer, and human health cancer.
For the development of the comparative lignocellulosic biomass conversion LCA, lignocellulosic biomass was converted to ethanol and higher alcohols through thermochemical gasification and alcohol synthesis process, to liquid biofuels via thermochemical gasification and FTS process, and to liquid biofuels via a thermochemical gasification and FTS process that uses methane. Overall results from the lignocellulosic biomass conversion LCA showed that the process that converts lignocellulosic biomass into alcohols has the highest overall environmental impact. Results also showed that the impact categories that appear to contribute the most to the overall impacts are ecotoxicity, human health non-cancer, human health cancer, and global warming.
This study determined that cultivated algae biomass feedstock has much higher environmental impacts compared with lignocellulosic biomass feedstock from forestation and agriculture byproducts. It was also concluded that thermochemical gasification and FTS process showed higher efficiency when converting biomass to bioenergy.
In addition, the five biomass to bioenergy conversion pathways used in the development of this LCA study were compared. Results showed that the pathway with lignocellulosic biomass (feedstock), thermochemical gasification and alcohol synthesis process (conversion process), and ethanol and higher alcohols (energy products) has the largest environmental impact.
29
Ariduru, Secil. "Fatigue Life Calculation By Rainflow Cycle Counting Method." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605614/index.pdf.
Full textAbstract:
In this thesis, fatigue life of a cantilever aluminum plate with a side notch under certain loading conditions is analyzed. Results of experimental stress analysis of the cantilever aluminum plate by using a uniaxial strain gage are presented. The strain gage is glued on a critical point at the specimen where stress concentration exists. Strain measurement is performed on the base-excited cantilever beam under random vibration test in order to examine the life profile simulation.
The fatigue analysis of the test specimen is carried out in both time and frequency domains. Rainflow cycle counting in time domain is examined by taking the time history of load as an input. Number of cycles is determined from the time history. In frequency domain analysis, power spectral density function estimates of normal stress are obtained from the acquired strain data sampled at 1000 Hz. The moments of the power spectral density estimates are used to find the probability density function estimate from Dirlik&rsquos empirical expression. After the total number of cycles in both time and frequency domain approaches are found, Palmgren-Miner rule, cumulative damage theory, is used to estimate the fatigue life. Results of fatigue life estimation study in both domains are comparatively evaluated. Frequency domain approach is found to provide a marginally safer prediction tool in this study.
30
Nishanth, Rini. "Dynamic Response and Life-Cycle Analysis of Floating Production Storage and Offloading Systems." Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/70517.
Full text
31
Amores, Barrero María José. "Environmental Management In Agriculture Based On Water And Climate Change Assessments: Tools For Decision Making By Life Cycle Approach." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/283235.
Full textAbstract:
The irrigated world area has been increased dramatically from the mid of 20th century. Freshwater use and its consumption have emerged as areas of high environmental concern. Although agricultural lands represent only 12% of the world’s land area, roughly 70% of water withdrawn from aquifers, streams and lakes are for irrigated agriculture. Climate change is a truly global problem around the world and the contribution from the agricultural sector is significantly high. Consequently, the environmental impacts from the use of water by agricultural activities and their relative contribution to Greenhouse Gas emissions should be properly addressed.
The present thesis aims mainly to assess the environmental performance of different agricultural systems through the application of Life Cycle Assessment and other complementary methods. Two main environmental impacts were considered: Global Warming and Water Footprint. The objective is to provide farmers with methodological and practical decision- making tools to help them to practice in sustainable agriculture.La superficie mundial de regadío ha aumentado drásticamente desde la segunda mitad del siglo XX. El uso de agua dulce y su consumo se han convertido en áreas de interés ambiental. Aunque las tierras agrícolas representan sólo el 12% de la superficie terrestre del mundo, aproximadamente el 70% del agua extraída de los acuíferos, ríos y lagos se utiliza para la agricultura de regadío. El cambio climático es un conocido problema global en todo el mundo y la contribución del sector agrícola es significativamente alta. Consiguientemente, los impactos ambientales procedentes del uso del agua debido a las actividades agrícolas y su relativa contribución en la emisión de Gases de Efecto Invernadero deben ser tratados adecuadamente. La presente tesis tiene como objetivo principal evaluar el perfil ambiental de los diferentes sistemas agrícolas a través de la aplicación del Análisis de Ciclo de Vida y otras herramientas complementarias. Principalmente, se consideraron dos impactos ambientales: el Calentamiento Global y la Huella Hídrica. El objetivo es proporcionar a los agricultores herramientas metodológicas y prácticas para la toma de decisiones y poder así practicar una agricultura sostenible.
32
Pérez, Vilaró Gemma 1985. "Cellular processing bodies and the hepatitis C virus life cycle : characterization of their dynamic interplay." Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/97092.
Full textAbstract:
Els cossos de processament (cossos-P) són grànuls discrets i dinàmics que contenen mRNAs represos en la traducció així com proteïnes involucrades en la degradació dels mRNAs i de la maquinària dels miRNAs. Alguns components dels cossos-P, com els repressors de la traducció PatL1, LSm1 i DDX6, promouen la traducció i la replicació del virus de la hepatitis C (VHC) i d’altres virus RNA de polaritat positiva [RNA(+)]. A més a més, un genome wide screening en llevat va determinar que l’exonucleasa Xrn1, que també es localitza als cossos-P, pot afectar la taxa de recombinació d’un virus RNA(+) de plantes Així doncs, els components dels cossos-P estan estretament relacionats amb els cicles vitals dels virus RNA(+).
En l’estudi que aquí es presenta hem explorat la relació del VHC amb els cossos-P, demostrant que la infecció pel VHC promou canvis en la composició dels cossos-P a través de l’alteració de la localització d’aquells components que són necessaris per a la replicació viral. A més a més, hem demostrat que els components dels cossos-P però no els grànuls per se són necessaris per a la replicació del VHC. Addicionalment, hem posat a punt un sistema de detecció de recombinació en cultiu cel•lular basat en replicons del VHC que permet analitzar successos de recombinació i caracteritzar la possible participació dels components dels cossos-P en aquest mecanisme d’evolució. Amb aquest sistema s’han establert les primeres estimacions en la freqüència de recombinació del VHC indicant que la recombinació en aquest virus no és gaire comú. A més a més, la reducció del nivell d’expressió de Xrn1 no va alterar la taxa de recombinació del VHC indicant que la utilització de l’exonucleasa no és una característica general en la recombinació dels virus RNA(+). En conjunt, aquests resultats incrementen el nostre coneixement sobre els aspectes bàsics de la biologia del VHC així com de l’estreta relació que aquest virus estableix amb l’hoste.
33
Collado-Vindel, Maria Dolores. "Dynamic econometric models for cohort and panel data : methods and applications to life-cycle consumption." Thesis, London School of Economics and Political Science (University of London), 1994. http://etheses.lse.ac.uk/2829/.
Full textAbstract:
The purpose of this research is to analyze dynamic models for cohort and panel data, with special emphasis in the applications to life-cycle consumption. In the second chapter of the thesis we analyze the estimation of dynamic models from time-series of independent cross-sections. The population is divided in groups with fixed membership (cohorts) and the cohort sample means are used as a panel subject to measurement errors. We propose measurement error corrected estimators and we analyze their asymptotic properties. We also calculate the asymptotic biases of the non-corrected estimators to check up to what extent the measurement error correction is needed. Finally, we carry out Monte Carlo simulations to get an idea of the performance of our estimators in finite samples. The purpose of the second part is to test the life-cycle permanent income hypothesis using an unbalanced panel from the Spanish family expenditure survey. The model accounts for aggregate shocks and within period non-separability in the Euler equation among consumption goods, contrary to most of the literature in this area. The results do not indicate excess sensitivity of consumption growth to income. In the last chapter, we specify a system of nonlinear intertemporal (or Frisch) demands. Our choice of specification is based on seven criteria for such systems. These criteria are in terms of consistency with the theory, flexibility and econometric tractability. Our specification allows us to estimate a system of exact Euler equations in contrast to the usual practice in the literature. We then estimate the system on Spanish panel data. This is the first time that a Frisch demand system has been estimated on panel data. We do not reject any of the restrictions derived from theory. Our results suggest strongly that the intertemporal substitution elasticity is well determined.
34
Pflanz, Mark. "Addressing the Reliability and Life Cycle Cost Analysis Problem for Technology and System Developers Early in the DoD System Development Process." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/46185.
Full textAbstract:
Early in the process of developing or upgrading new weapon systems, Department of Defense (DoD) system and technology developers are faced with decisions regarding which technologies are appropriate for inclusion into the conceptual design. To reduce risk and improve decision making, system and technology developers need a capability to assess the impact of technology reliability on the attributable Operating and Support (O&S) cost of the system. Early understanding of the reliability implications of potential technologies on system O&S cost will help make better informed decisions early in the system development timeline, prior to points of design lock-in. Using a Marine Corps case study and a system dynamics simulation model, this thesis examines the nature of the relationship between component reliability and attributable changes in O&S cost. This thesis also develops a potential analysis methodology repeatable for future use. The modeling results indicate that this relationship is best described as exponential decay, meaning that the savings in O&S cost per system mile is proportional for any fixed incremental change in component reliability. We find these results to be insensitive to changes in preventative maintenance policies, maintenance deferment ratios, and component replacement cost. We completed verification and validation using the case study and existing Marine Corps systems, finding good association between the modeling results and the actual system. This analysis is valuable to the system and technology developer by helping to answer the question: "how reliable is reliable enough in terms of O&S cost" when considering technologies with uncertainties in long-term performance.Master of Science
35
Petersen, Abdul Muhaymin. "Comparisons of the technical, financial risk and life cycle assessments of various processing options of sugercane bagasse to biofuels in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20156.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2012ENGLISH ABSTRACT: Through many years of research, a number of production schemes have been developed for converting lignocellulosic biomass into transport fuels. These technologies have been assessed through a number of techno-economic studies for application in a particular context in terms of the technical and economic feasibility. However, previous studies using these methods have tended to lack vigour in various aspects. Either the energy efficiency of the processes were not maximised through adequate heat integration, or a competing technology which existed was not considered. From an economic perspective, the financial models would often lack the vigour to account for the risk and uncertainty that is inherent in the market prices of the commodities. This phenomenon is especially relevant for the biofuel industry that faces the full fledge of uncertainties experienced by the agricultural sector and the energy sector. Furthermore, from an environmental perspective, the techno-economic studies had often ignored the environmental impacts that are associated with biofuel production. Thus, a comparative study could have favoured an option due to its economic feasibility, while it could have had serious environmental consequences. The aim of this study was to address these issues in a South African context, where biofuels could be produced from sugarcane bagasse. The first step would be to modify an existing simulation model for a bioethanol scenario that operates with a Separate Hydrolysis and Fermentation (SHF process) configuration into a second processing scenario that operates with a Simultaneous Saccharification and Fermentation (SSF process) configuration using reliable experimental data. The second step was to ensure that the maximum energy efficiency of each scenario was realised by carrying out pinch point analysis as a heat integration step. In contrast to these biological models is the thermochemical model that converts bagasse to gasoline and diesel via gasification, Fischer-Tropsch synthesis and refining (GFT process). While there were no significant advances in technology concerning this type of process, the energy efficiency was to be maximised with pinch point analysis. The GFT process obtained the highest energy efficiency of 50.6%. Without the affects of pinch point technology, the efficiency dropped to 46%, which thus emphasises the importance of heat integration. The SSF had an efficiency of 42.8%, which was superior to that of the SHF at 39.3%. This resulted from a higher conversion of biomass to ethanol in the SSF scenario. Comparing the SHF model to an identical model found in literature that did not have pinch point retrofits, this study showed lower efficiency. This arose because the previous study did not account for the energy demands of the cold utility systems such as the cooling tower operation, which has been shown in this study to account for 40% of the electrical energy needs. The economic viability of all three processes was assessed with Monte Carlo Simulations to account for the risks that the fluctuations in commodity prices and financial indices pose. This was accomplished by projecting the fluctuations of these parameters from samples of a historical database that has been transformed into a probability distribution function. The consequences were measured in terms of the Net Present Value (NPV) and Internal Rate of Return (IRR) for a large number of simulations. The results of these variables were aggregated and were then assessed by testing the probability that the NPV<0, and that the IRR recedes below the interest rate of 12.64%. The investment was thus deemed unfeasible if these probabilities were greater than 20%. Both biological models were deemed profitable in terms of this standard. The probabilities were 13% for the SSF and 14% for the SHF. The GFT process however was deemed completely unfeasible because the probability that the NPV<0 was 78%. Given that the GFT process had the highest energy efficiency, this result arises mainly because the capital investment of 140,000USD/MWHHV of biomass energy input is to enormous for any payback to be expected. The environmental footprint of each process was measured using Life Cycle Assessments (LCAs). LCAs are a scientifically intricate way of quantifying and qualifying the effects of a product or process within a specified boundary. The impacts are assessed on a range of environmental issues, such as Global Warming, Acidification, Eutrophication and Human toxicity. Furthermore, if the project under concern has multiple output products, then the impacts are distributed between the output products in proportion to the revenue that each generates. The impacts were either relative to the flow of feedstock, which was 600MW of bagasse, or to the functional unit, which was the amount of fuel required to power a standard vehicle for a distance of 1 kilometre. In either case, the GFT scenario was the least burdening on the environmental. This was expected because the GFT process had the highest energy efficiency and the process itself lacked the use of processing chemicals. Relative to the feedstock flow, the SSF was the most environmentally burdening scenario due to the intensive use of processing chemicals. Relative to the functional unit, the SHF was the most severe due to its low energy efficiency. Thus, the following conclusions were drawn from the study: The GFT is the most energy and environmentally efficient process, but it showed no sign of economic feasibility. iv There is no significant difference in the economic and environmental evaluation of the SSF and SHF process, even though the SSF is considered to be a newer and more efficient process. The major cause of this is because the setup of the SSF model was not optimised.
AFRIKAANSE OPSOMMING: Deur baie jare van navorsing is ‘n aantal produksie-skemas vir die omskakeling van lignosellulose biomassa na vloeibarebrandstof ontwikkel. Hierdie tegnologië is geassesseer ten opsigte van die tegniese en ekonomiese haalbaarheid deur middel van tegno-ekonomiese studies in bepaalde tekste. Tog het hierdie vorige studies besliste beperkings gehad. Of die energie-doeltreffendheid van die proses is nie gemaksimeer deur voldoende hitte-integrasie nie, of 'n mededingende tegnologie wat bestaan is nie oorweeg nie. Vanuit 'n ekonomiese perspektief, was die finansiële modelle dikwels nie die omvattend genoeg om rekening te hou met die risiko en onsekerheid wat inherent is in die markpryse van die kommoditeite nie. Hierdie verskynsel is veral relevant vir die biobrandstof bedryf wat die volle omvang van onsekerhede ervaar waaraan die landbousektor en die energiesektoronderhewig is. Verder het die tegno-ekonomiese studies dikwels die omgewingsimpakte wat verband hou met biobrandstofproduksie geïgnoreer. Dus kon ‘n opsie deur die ekonomiese haalbaarheid bevoordeel word, ten spyte van die ernstige omgewingsimpakte wat dit kon inhou. Die doel van hierdie studie was om hierdie kwessies aan te spreek in 'n Suid-Afrikaanse konteks, waar biobrandstof uit suikerriet bagasse geproduseer kan word. Die eerste stap was om 'n bestaande simulasiemodel vir 'n bio-scenario wat met Afsonderlike Hidroliese en Fermentasie (SHF proses) stappe werk, te modifiseer vir 'n tweede verwerking scenario wat met 'n gelyktydige Versuikering en Fermentasie (SSF proses) konfigurasie werk. Die verandering is gedoen deur die gebruik van betroubare eksperimentele data. Die tweede stap was om te verseker dat elke scenario die maksimum energie-doeltreffendheid het, deur 'n hitte-integrasie stap, wat gebruik maak van “pinch-point” analise. In teenstelling met hierdie biologiese modelle, is daar die thermochemiese roete waar petrol en diesel van bagasse vervaardig word via vergassing, Fischer-Tropsch-sintese en rafinering (GFT proses). Daar was geen betekenisvolle vooruitgang in tegnologie vir hierdie proses nie, maar die energie-doeltreffendheid is gemaksimeer word deur energie-integrasie. Die GFT proses toon die hoogste energie-doeltreffendheid van 50,6%. Sonder die invloed van energie-integrasie het die doeltreffendheid gedaal tot 46%, wat dus die belangrikheid van hitte-integrasie beklemtoon. Die SSF het 'n effektiwiteit van 42,8% gehad, wat beter was as dié 39,3% van die SHF opsie. Hierdie hoër effektiwiteit wasas gevolg van die hoër omskakeling van biomassa na etanol in die SSF scenario. Die energie doeltreffendheid vir die SHF-model was laer as met 'n identiese model (sonder energie-integrasie) wat in die literatuur gevind wat is. Dit het ontstaan omdat die vorige studie nie 'n volledig voorsiening gemaak het met die energie-eise van die verkillingstelselsnie, wat tot 40% van die elektriese energie behoeftes kan uitmaak. Die ekonomiese lewensvatbaarheid van al drie prosesse is bepaal met Monte Carlo simulasies om die risiko's wat die fluktuasies in kommoditeitspryse en finansiële indekse inhou, in berekening te bring. Hierdie is bereik deur die projeksie van die fluktuasies van hierdie parameters aan die hand van 'n historiese databasis wat omskep is in 'n waarskynlikheid verspreiding funksie. Die gevolge is gemeet in terme van die netto huidige waarde (NHW) en Interne Opbrengskoers (IOK) vir 'n groot aantal simulasies. Die resultate van hierdie veranderlikes is saamgevoeg en daarna, deur die toets van die waarskynlikheid dat die NPV <0, en dat die IRR laer as die rentekoers van 12,64% daal, beoordeel. Die belegging is dus nie realiseerbaar geag as die waarskynlikhede meer as 20% was nie. Beide biologieseprosesse kan as winsgewend beskou word in terme van bostaande norme. Die waarskynlikhede was 13% vir die SSF en 14% vir die SHF. Aangesien die NHW van die GFT-proses onder 0 met ‘n waarskynlikheid van 78% is, is die opsie as nie-winsgewend beskou. Gegewe dat die GFT-proses die hoogste energie-doeltreffendheid het, is die resultaat hoofsaaklik omdat die kapitale belegging van 140,000 USD / MWHHV-biomassa energie-inset te groot is, om enige terugbetaling te verwag. Die omgewingsvoetspoor van elke proses is bepaal deur die gebruik van Lewens Siklus Analises (“Life Cycle Assessments”) (LCAS). LCAS is 'n wetenskaplike metodeom die effek van ‘n produk of proses binne bepaalde grense beide kwalitatief en kwantitatief te bepaal. Die impakte word beoordeel vir 'n verskeidenheid van omgewingskwessies, soos aardverwarming, versuring, eutrofikasie en menslike toksisiteit. Voorts, indien die projek onder die saak verskeie afvoer produkte het, word die impakte tussen die afvoer produkte verdeel, in verhouding tot die inkomste wat elkeen genereer. Die impak was met of relatief tot die vloei van roumateriaal (600MW van bagasse), of tot die funksionele eenheid, wat die hoeveelheid van brandstof is om 'n standaard voertuig aan te dryf oor 'n afstand van 1 kilometer. In al die gevalle het die GFT scenario die laagste belading op die omgewing geplaas. Hierdie is te verwagte omdat die GFT proses die hoogste energie-doeltreffendheid het en die proses self nie enige addisionele chemikalieë vereis nie. Relatief tot die roumateriaal vloei, het die SSF die grootse belading op die omgewing geplaas as gevolg van die intensiewe gebruik van verwerkte chemikalieë. Relatief tot die funksionele eenheid, was die SHF die swakste as gevolg van sy lae energie-doeltreffendheid.
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Larsson, Mathias. "Environmental assessments and Swedish consumption of biofuels : Review of Swedish biofuel research and aggregated life cycle assessment of Swedish biofuel consumption 2000-2013." Thesis, KTH, Industriell ekologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172050.
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This thesis assesses the potential environmental impacts for Swedish biofuel consumption and evaluates the environmental scope in Swedish biofuel research. The biofuel consumption is portrayed with life cycle assessment methodology and presents the emissions occurring from different feedstock and fuel production regions. The outcome of the biofuel consumption is compared with a fossil fuel scenario in order to put the emissions of biofuels in broader context. A systematic literature review is conducted on the published Swedish environmental system analysis on biofuels, to quantitatively interpret assessed environmental indicators and methods. The findings are that while global warming potential emissions decreased, local environmental impact potentials increases drastically. Most of the environmental burdens from the consumption have occurred in the EU and South America. Results from the systematic literature review shows on a dominating scope towards global warming potential and energy performance of the fuels. The justifications for the low consideration of other impact categories are often without motivation. Implications occurring from the limited scope are discussed in terms of potential problem shifting and its correspondence to Swedish environmental policy. The biofuel policies from the European Union and the Swedish Government are insufficient regarding mitigation of e.g. eutrophication, acidification and toxicity. Impacts from land use change and indirect land use change are also highly important to include in the assessments.I denna masteruppstats bedöms de potentiella miljöeffekterna för Svensk biodrivmedelskonsumtion och analysomfattningen i den Svensk biodrivmedelsforskningen. Sveriges konsumtion av biodrivmedel är miljömässigt bedömd genom livscykelanalys, där emissioner från råvaruframställning och produktion presenteras över uppkomstområde åren 2000-2013. De olika påverkansindikatorerna jämförs med miljöpåverkan från förbränning av fossila drivmedel med samma energiinnehåll. En systematisk litteraturundersökning genomförs över alla svenskpublicerade vetenskapliga artiklar i syfte att kvantitativt bedöma omfattningen av påverkanskategorier. Resultaten visar att samtidigt som växthusgaserna minskat har andra påverkanskategorier ökat dramatiskt. Den bedömda miljöpåverkan till följd av biodrivmedelskonsumtionen skedde till största delen i Europeiska och Sydamerikanska länder. Resultatet från den systematiska litteraturundersökningen visar ett övervägande i miljöpåverkansfokus på växthusgasutsläpp och energiprestanda i forskningen. Valet av påverkanskategorier är ofta undermåligt beskrivet och motivering till de studerade påverkansområdena saknas i majoriteten av rapporterna. Konsekvenserna av denna snäva miljöpåverkanssyn är diskuterad i förhållande till problemförflyttning och svensk miljöpolicy. Biodrivmedels strategier från Europeiska Unionen och den svenska regeringen är bristfälliga för att minska t. ex. övergödning, försurning och toxicitet. Påverkan från förändrad landanvändning och indirekt förändrad landanvändning är även de viktiga att medta i bedömningarna.
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Romaniw, Yuriy. "An activity based method for sustainable manufacturing modeling and assessments in SysML." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34717.
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Traditionally, environmental impacts of man made products have been determined by performing a life cycle assessment (LCA) on the product. As the name implies, LCA is usually covers the entire life of the product in a so-called "cradle-to-grave" assessment. In determining environmental impacts over the whole product life, LCA's are reasonably adequate. However, in providing detailed impacts on a particular phase of life, LCA's are lacking. Detailed assessments are important because very few stakeholders have influence over a product during all phases of life. Stakeholders need detailed impact assessments in their particular phase of life. More detailed assessments give stakeholders more information that can be used for better environmental management (EM) and more environmentally benign operations. In many LCA's, the manufacturing phase of life has been over-generalized and over-simplified because of its relatively small environmental impact, as compared to other phases of life. Nevertheless, certain stakeholders, such as manufacturing companies, need detailed impact information for the manufacturing phase of life so that they can create a more sustainable manufacturing process. Most traditional LCA's use a case-based approach, which was deemed to be inadequate. For these LCA's, the information provided for each case is often quite detailed and specific. However, this makes the assessment less flexible, limiting the quality of the assessment to the degree that the current scenario matches the existing cases. In order to make a more user-specific assessment, a model-based approach was used. To give the model flexibility, a parametric model was created based on mathematical equations that represent various parts of the manufacturing process. To give the model structure, an activity-based costing (ABC) approach was used. Using the ABC structure, the manufacturing process was broken down into activities, each of which was characterized by mathematical models. Large models would be difficult to construct and simulate by hand, so a model was built with the aid of a computer. The modeling language SysML (Systems Modeling Language) was used to create an object-oriented model of the manufacturing process, using the ABC structure. SysML defines overall properties and behaviors of the various elements in the model, while the plug-in tool ParaMagic was used to execute the model via a Mathematica Solver. The model computes carbon dioxide emissions, energy consumption, and waste mass generation for a particular manufacturing scenario. The goal of the model was to quantify environmental impact factors in order to aid manufacturing stakeholders in EM. The overall goal of the research was to determine whether an activity-based, object-oriented model was a valid approach, and whether the computer-aided tools adequately implemented this approach. Findings show that SysML is capable of modeling large and complex systems. However, due to some limitations of Paramagic, only some of SysML's capabilities were utilized. Nevertheless, Paramagic is capable of extracting information out of a manufacturing model built in SysML, and solving parametric relations in Mathematica in a timely manner. Timely solutions of complex models are critical for stakeholders keeping a competitive edge.
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Karlsson, Malin, and Linnea Sund. "Life cycle assessments of arable land use options and protein feeds : A comparative study investigating the climate impact from different scenarios in the agricultural sector." Thesis, Linköpings universitet, Industriell miljöteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129462.
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The aim of this study was to investigate and compare the climate impact from different arable land use options and protein feeds aimed for cattle. This has been made by executing two life cycle assessments (LCAs). The first LCA aimed to compare the following three arable land use options: Cultivation of wheat used for production of bioethanol, carbon dioxide and DDGS Cultivation of rapeseed used for production of RME, rapeseed meal and glycerine Fallow in the form of long-term grassland The second LCA aimed to compare the three protein feeds DDGS, rapeseed meal and soybean meal. In the LCA of arable land, the functional unit 1 ha arable land during one year was used and the LCA had a cradle-to-grave perspective. The LCA of protein feeds had the functional unit 100 kg digestible crude protein and had a cradle-to-gate perspective, hence the use and disposal phases of the feeds were excluded. Bioethanol, DDGS and carbon dioxide produced at Lantmännen Agroetanol, Norrköping, were investigated in this study. The production of RME, rapeseed meal and glycerine were considered to occur at a large-scale plant in Östergötland, but no site-specific data was used. Instead, general data of Swedish production was used in the assessment. The wheat and rapeseed cultivations were considered to take place at the same Swedish field as the fallow takes place. The protein feed DDGS was produced at Lantmännen Agroetanol and the rapeseed meal was assumed to be produced at a general large-scale plant in Sweden. In the soybean meal scenario, a general case for the Brazilian state Mato Grosso was assumed and no specific production site was investigated. Data required for the LCAs was retrieved from literature, the LCI database Ecoinvent and from Lantmännen Agroetanol. In the LCA of arable land use options, system expansion was used on all products produced to be able to compare the wheat and rapeseed scenarios with the fallow scenario. In the LCA of protein feeds, system expansion was used on co-products. The products in the arable land use options and the co-products in the protein feed scenarios are considered to replace the production and use of products on the market with the same function. The result shows that the best arable land use option from a climate change perspective is to cultivate wheat and produce bioethanol, carbon dioxide and DDGS. This is since wheat cultivation has a higher yield per hectare compared to rapeseed and therefore a bigger amount of fossil products and feed ingredients can be substituted. To have the arable land in fallow is the worst option from a climate change perspective, since no products are produced that can substitute alternative products. Furthermore, the result shows that DDGS and rapeseed meal are to prefer before soybean meal from a climate change perspective, since soybean meal has a higher climate impact than DDGS and rapeseed meal. This can be explained by the smaller share of co-products produced in the soybean meal scenario compared to the DDGS and rapeseed meal scenarios. Since the production and use of co-products leads to avoided greenhouse gas emissions (since they substitute alternatives), the amount of co-products being produced is an important factor. A sensitivity analysis was also executed testing different system boundaries and variables critical for the result in both LCAs. The conclusion of this study is that arable land should be used to cultivate wheat in order to reduce the total climate impact from arable land. Furthermore, it is favorable for the climate if DDGS or rapeseed meal are used as protein feeds instead of imported soybean meal.
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Haugsbakk, Frida. "Evaluations of how carbon dioxide calculations can be integrated into 3D models at an early design stage for more efficient Life Cycle Assessments on buildings." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230168.
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Life Cycle Assessments on buildings and various environmental certificates are starting to become customary for newbuilding projects in Sweden. Building materials play a big part in a building’s environmental impact. Earlier research indicates that Life Cycle Assessments is not a routine in today’s construction process and it may depend on uncertainties in the methods of quantifying carbon dioxide emissions. This master thesis focuses on how equivalent carbon dioxides, a standard unit to quantify greenhouse gas emissions, of building materials can be integrated with Building Information Modelling. Through meetings with experts in the field, data has been collected. A 3D model of a house was built in order to evaluate both an integration with a cost calculation tool and directly with the 3D model. The results showed how the cost calculation tool works for calculations of equivalent carbon dioxides, early in the pre-construction phase. Difficulties in finding corresponding materials in their database were found and issues with summarizing carbon dioxide data. The integration directly into the 3D model, with visual programming, proved an insert for each materials’ carbon dioxide emissions worked. This allows further updates throughout the building process. It was also possible to import material information to a carbon dioxide calculation tool. This evaluation opened up a possibility to change and update carbon dioxide emissions at an early design stage of a building process with Building Information Modelling along with a need of organizational change due to today's traditional building processes.Livscykelanalyser på byggnader och olika typer av miljöbyggnads-certifieringar blir allt vanligare för nya byggprojekt i Sverige. Materialet i en byggnad spelar en stor roll av hela byggnadens miljöpåverkan. Tidigare forskning indikerar att livscykelanalyser inte är en rutin i dagens byggprocesser vilket kan bero på att osäkerheter i de olika metoderna bakom koldioxidberäkningar. Den här artikeln fokuserar på hur koldioxidekvivalenter av byggnadsmaterial kan bli integrerade med Byggnadsinformationsmodellering. Genom möten med experter i området har datainsamling gjorts för det ändamålet. För att undersöka integreringen byggdes en 3D-modell upp och som senare användes för beräkningar av koldioxidutsläpp i ett kostnads-kalkyleringsverktyg samt undersöka hur en införing av koldioxidekvivalenter direkt i 3D-modellen kunde göras. Resultaten visade hur kostnads-beräkningsverktyget fungerar för beräkningar av koldioxidekvivalenter, tidigt i byggprocessen. Svårigheter i att hitta motsvarande material i kalkyleringsverktygets databas upptäcktes under utvärderingen samt en sammanfattande rapport för beräkningarna. Integrationen direkt i 3D-modellen med visuell programmering visade att en inmatning av koldioxidutsläpp för varje material fungerade vilket möjliggör uppdateringar under hela byggprocessen. Det var också möjligt att importera materialinformation till ett koldioxidberäkningsverktyg. Det öppnar upp möjligheter att ändra och uppdatera koldioxidutsläpp för material tidigt i byggprocessen med hjälp av Byggnadsinformationsmodellering och visar behov av organisationsförändringar på grund av dagens traditionella byggprocess.
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Fujiwara, Ippei. "Three essays on dynamic general equilibrium models." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:b963d031-cd68-4bee-91b7-4541e5d600d2.
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This thesis aims at contributing to the existing studies in the dynamic stochastic general equilibrium model, particularly in the new Keynesian models, on three aspects. It consists of three chapters. Chapter 2 is on “Dynamic new Keynesian Life-Cycle Model.” Chapter 3 is on “Re-thinking Price Stability in an Economy with Endogenous Firm Entry: Real Imperfections under Product Variety.” Chapter 4 is on “Growth Expectation.” Abstracts of each Chapter are as follows. In Chapter 2, we first construct a dynamic new Keynesian model that incorporates life-cycle behavior a la Gertler (1999), in order to study whether structural shocks to the economy have asymmetric effects on heterogeneous agents, namely workers and retirees. We also examine whether considerations of life-cycle and demographic structure alter the dynamic properties of the monetary business cycle model, specifically the degree of amplification in impulse responses. According to our simulation results, shocks indeed have asymmetric impacts on different households and the demographic structure does alter the size of responses against shocks by changing the trade-off between substitution and income effects. In Chapter 3, we re-think price stability in an economy with endogenous firm entry under possible distortions. We first demonstrate that endogenous entry causes real imperfections. Reflecting fluctuations in the number of varieties, the gap between the natural and the efficient level of output is no longer constant and variant to shocks. As a result, the central bank faces a trade-off between stabilizing inflation and welfare-relevant output gap. Then, we show that this results in the non-zero optimal rate of inflation. We further check whether welfare can be enhanced by targeting welfare-based inflation instead of cross-sectional average inflation contrary to the previous findings. Simulations even with such distortions as unknown natural interest rate or no fiscal remedy for efficient non-stochastic steady states, however, support cross-sectional average inflation targeting although there may exist some small gains by referring also to welfare-based inflation rates. Incomplete stabilization may enhance welfare in an economy when agents cannot internalize the externality on the love for variety. Chapter 4 is about the difficulty in producing reasonable business cycles for the expectation shock about higher future technology. For a long time, changes in expectations about the future have been thought to be significant sources of economic fluctuations, as argued by Pigou (1926). Although creating such an expectation-driven cycle (the Pigou cycle) in equilibrium business cycle models was considered to be a difficult challenge, as pointed out by Barro and King (1984), recently, several researchers have succeeded in producing the Pigou cycle by balancing the tension between the wealth effect and the substitution effect stemming from the higher expected future productivity. Seminal research by Christiano et al. (2007a) explains the “stock market boom-bust cycles,” characterized by increases in consumption, labor inputs, investment and the stock prices relating to high expected future technology levels, by introducing investment growth adjustment costs, habit formation in consumption, sticky prices and an inflation-targeting central bank. We, however, show that such a cycle is difficult to generate based on “growth expectation,” which reflect expectations of higher productivity growth rates. Thus, Barro and King’s (1984) prediction still applies.
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Schade, Susann [Verfasser], Gabriele I. [Gutachter] Stangl, and Martina [Gutachter] Gerken. "Distinct microalgae for human nutrition : comparative life cycle assessments and techno-economic analysis of microalgae cultivation ; [kumulative Dissertation] / Susann Schade ; Gutachter: Gabriele I. Stangl, Martina Gerken." Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2020. http://d-nb.info/1220698180/34.
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Torres, De Miranda Pinto Julian. "Sustainable resource management in european steel supply chains." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAD002/document.
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La présente thèse entend examiner les interactions présentes et futures entre l'industrie sidérurgique européenne et son environnement, avec pour objectifs principaux, l’amélioration de la prise de décision et l'élaboration de politiques industrielles en matière de durabilité et de circularité. La thèse contribue à l’émergence de propositions contribuant à façonner l'avenir de l'acier dans l’Union Européenne. L'industrie sidérurgique européenne est utilisée ici comme un cas d’école, visant à explorer les avantages potentiels pour l’économie circulaire et l’écologie industrielle, d’une intégration d’un outil (Analyse du Cycle de Vie – ACV) dans une méthodologie (Dynamique des Systèmes – SD). Un modèle modulaire pour l’industrie sidérurgique européenne a été construit et, pour 4 des 5 articles développés dans la thèse, 21 simulations ont été effectuées. 12 simulations ont permis d’identifier les contraintes potentielles et les avantages des stratégies de fin de vie; 5 d’évaluer les avantages et les inconvénients des différentes stratégies d’intégration de la chaîne d’approvisionnement (SCI) dans la filière européenne de l’acier; et 4 de traiter des interactions entre les dynamiques biophysiques et économiques sur le marché de l'acier. Le dernier article s’appuie sur une nouvelle méthodologie – les Cercles de Durabilité et le Métabolisme Urbain Durable – pour évaluer les défis et les contributions de l'acier dans le cadre de l’éco-fonctionnalité en milieu urbain. Les résultats ont montré que l’intégration de l’ACV dans les stratégies de développement durable permettait de reproduire assez fidèlement les résultats et les scénarios d’études scientifiques antérieures, tout en suggérant des apports méthodologiques relativement novateurs. Cette recherche opérationnelle est susceptible d'intéresser les managers et des chefs d’entreprises qui s’attachent aux questions d’efficience et de résilience de l’outil industriel, ainsi que les décideurs politiques qui souhaitent cerner les enjeux d’une pénurie de matières premières ou d’une politique de recyclage de l’acier à l’échelle européenne. D'après les résultats de chaque article, il a été observé que (a) le recyclage et la réutilisation pourraient générer des résultats intéressants à moyen et à long terme en matière de circularité, en abandonnant notamment les combustibles fossiles et en développant un tout nouveau marché autour des services de fin de vie; (b) différentes approches en matière de chaine logistique intégrée semblent être prometteuses d'un point de vue environnemental et stratégique; (c) six variables biophysiques clés peuvent avoir une incidence notoire sur les cours au comptant, les cours à terme, les marges d'EBITDA, l'utilisation des capacités de production, la distribution des dividendes et les coûts de fabrication de l'acier; et (d) la dynamique servicielle dans le cadre de l’éco-fonctionnalité peut apporter des avantages significatifs aux villes durables, tout en modifiant considérablement la structure de l’offre sur le marché de l’acierThe present thesis delved into the current and future interactions within the European Steel Industry and of it with the environment it is a part of, with the main objective of supporting decision- and policy-making efforts oriented towards sustainability and circularity, helping to shape the future of steel in the European Community. The thesis used the European Steel Industry as a case study to explore the potential benefits of integrating Life Cycle Assessment (LCA) into System Dynamics (SD) under the scopes of Circular Economy and Industrial Ecology. A model representative of the European Steel Industry was built modularly in Stella Architect, following ILCD and ISO guidelines and standards for LCA. Throughout 4 of the 5 articles developed for the present thesis, 21 simulation runs were performed on the aforementioned model: 12 on identifying potential constraints and benefits of End-of-Life policies; 5 assessing the advantages and disadvantages of different Supply Chain Integration (SCI) strategies along European steel supply chains; and 4 addressing the interactions between biophysical and economic dynamics in the steel market. An additional article was developed using the methodologies of Circles of Sustainability and Sustainable Urban Metabolism to appraise the challenges and contributions of steel as part of servitization initiatives in urban environments. Overall results indicated that integrating LCA into SD was not only feasible and capable of reproducing results, trends and behaviors from previous scientific studies, but also of contributing to both methodologies in different levels. This approach has potential to interest policy-makers who seek more granularity within the European Steel Industry as well as decision-makers searching for a broader understanding of their operation’s dynamics beyond the gates, notably regarding raw material scarcity, resource self-sufficiency, and resource ownership retention. From the results of each article it was observed that, (a) pushing for recycling and reuse could generate interesting medium- to long-term results for circularity, transitioning away from fossil fuels and developing a whole new market around end-of-life services; (b) different SCI approaches can be environmentally and strategically promising; (c) six key biophysical variables can distinctively affect spot prices, future prices, EBITDA margins, capacity utilization, dividend payouts, and costs of steelmaking; and (d) servitization can provide significant benefits to sustainable cities, while also being able to substantially alter the supply-side dynamics of steelmaking, highlighting how important it is for steelmakers to pay close attention to the service-providing initiatives that may concern their clients and products
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Hüppe, Christian [Verfasser]. "Efficiency loss of household refrigeration appliances over time and associated impacts: Dynamic modelling of operational features and life-cycle / Christian Hüppe." Düren : Shaker, 2021. http://d-nb.info/1236834461/34.
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Pesonen, L. T. (Lasse T. T. ). "Implementation of design to profit in a complex and dynamic business context." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514264509.
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Abstract
The objective of this thesis is to demonstrate a design to profit procedure
and its implementation in industrial case environment. The procedure is
demonstrated as a way to improve profits in a global company. The essential
elements of the procedure are product business case calculations and profit
consciousness of employees. This study utilizes a combination of product life
cycle analysis, advanced costing methods and multidimensional data processing for
the product business case calculations. The combination is necessary for solving
the research task.
The need of proactive design is emphasized in the telecommunications
industry due to shorter and shorter product life cycles. However, traditional
accounting methods do not support proactive design work sufficiently during the
life cycle of the products. The design to profit procedure has been created to
help business managers to solve following problems:
1. How to proactively ensure the growth of business profits in the
future?
2. How to prevent suboptimal decisions from being made in functional units
and to promote overall profitability?
3. How to judge the profitability of new product programs within a
company?
4. How can we ensure an adequate level of cost consciousness and
profitability-driven targets for the company's key employees?
This study presents and discusses the construction of the procedure and
describes its elements, implementation and use in practice. The argumentation is
illustrated by case studies. This method has benefits, especially when the
product life cycles are short and the market competition strong.
The design to profit procedure is a proactive mind set or thinking pattern.
This system makes the employees aware of the importance target profitability and
especially target costing. There is no decision support system that could
guarantee the profitability of business. Cautious utilization of the system
results and common sense are required to achieve continuous growth of business
profits.
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Ozcan-Deniz, Gulbin. "An Integrated Multi-Agent Framework for Optimizing Time, Cost and Environmental Impact of Construction Processes." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/455.
Full textAbstract:
Environmentally conscious construction has received a significant amount of research attention during the last decades. Even though construction literature is rich in studies that emphasize the importance of environmental impact during the construction phase, most of the previous studies failed to combine environmental analysis with other project performance criteria in construction. This is mainly because most of the studies have overlooked the multi-objective nature of construction projects. In order to achieve environmentally conscious construction, multi-objectives and their relationships need to be successfully analyzed in the complex construction environment. The complex construction system is composed of changing project conditions that have an impact on the relationship between time, cost and environmental impact (TCEI) of construction operations. Yet, this impact is still unknown by construction professionals. Studying this impact is vital to fulfill multiple project objectives and achieve environmentally conscious construction. This research proposes an analytical framework to analyze the impact of changing project conditions on the relationship of TCEI. This study includes green house gas (GHG) emissions as an environmental impact category. The methodology utilizes multi-agent systems, multi-objective optimization, analytical network process, and system dynamics tools to study the relationships of TCEI and support decision-making under the influence of project conditions. Life cycle assessment (LCA) is applied to the evaluation of environmental impact in terms of GHG. The mixed method approach allowed for the collection and analysis of qualitative and quantitative data. Structured interviews of professionals in the highway construction field were conducted to gain their perspectives in decision-making under the influence of certain project conditions, while the quantitative data were collected from the Florida Department of Transportation (FDOT) for highway resurfacing projects. The data collected were used to test the framework. The framework yielded statistically significant results in simulating project conditions and optimizing TCEI. The results showed that the change in project conditions had a significant impact on the TCEI optimal solutions. The correlation between TCEI suggested that they affected each other positively, but in different strengths. The findings of the study will assist contractors to visualize the impact of their decision on the relationship of TCEI.
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Babi, Almenar Javier. "Characterisation, biophysical modelling and monetary valuation of urban nature-based solutions as a support tool for urban planning and landscape design." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/288810.
Full textAbstract:
The recognition of nature in the resolution of societal challenges has been growing in relevance. This recognition has been associated with the development of new concepts from science and policy such as natural capital, ecosystem services, green infrastructure, and more recently Nature-Based Solutions (NBS). NBS intends to address societal challenges in an effective and adaptive form providing economic, social, and environmental benefits. The overall aim of this PhD thesis is to develop an environmental and economic assessment of NBS for highly urbanised territories based on rationales and models underpinning ecosystem services, urban/landscape ecology, and life cycle thinking approaches. This combined evaluation approach would help to better understand if NBS are cost-effective or not. The aim is developed according to four specific objectives.
The first objective corresponds to the characterisation of NBS in relation to urban contexts and the problematics that they can help to address or mitigate. To achieve this objective a critical review on the study of the relationship between NBS, ecosystem services (ES) and urban challenges (UC) was developed. As a main output, a graph of plausible cause-effect relationships between NBS, ES and UC is obtained. The graph represents a first step to support sustainable urban planning, moving from problems (i.e. urban challenges) to actions (i.e. NBS) to resolutions (i.e. ES).
The second objective corresponds to the definition of an adequate set of biophysical and monetary assessment methods and indicators to evaluate the value of NBS in urbanised contexts. To achieve this objective, a review of existing methods on ecosystem services valuation, life cycle cost analysis and life-cycle assessment are developed. The review takes into account specific constraints such as easiness to use and availability of data. At the end, potential methods and indicators were selected, which will be later integrated in the combined assessment framework.
The third objective corresponds to the design of a combined assessment framework integrating methods from life cycle assessment, landscape/urban ecology and ecosystem services that quantifies the environmental and economic value of NBS informing about the cost-effectiveness of its entire life cycle. To achieve this objective, a conceptual framework is developed. From it, a system dynamics model of ecosystem (dis)services is developed and coupled with a life cycle assessment method. The combined evaluation is tested with a relevant NBS type (i.e. urban forest) in a case study in the metropolitan area of Madrid.
The fourth objective is the development of a decision support (DSS) tool that integrates the assessment framework as part of iterative design processes in urban planning and landscape design. The DSS intends to enhance the interrelation between science, policy and planning/design. To achieve this objective a user-friendly web-based prototype DSS on NBS, called NBenefit$®, is developed. The prototype DSS provides the user a simple form of quantifying the provision of multiple ES and costs over the entire life cycle (implementation, operational life, and end-of-life) of NBS.
This thesis contributed to the characterisation of NBS and its environmental and economic assessment to inform urban planning and landscape design processes, allowing decisions that are more informed.Il riconoscimento della natura nella risoluzione delle sfide sociali è diventato sempre più importante. Questo riconoscimento è stato associato allo sviluppo di nuovi concetti provenienti dalla scienza e dalla politica, come il capitale naturale, i servizi ecosistemici, le infrastrutture verdi e, più recentemente, le soluzioni basate sulla natura (NBS). NBS intende affrontare le sfide della società in una forma efficace e adattabile fornendo benefici economici, sociali e ambientali. Lo scopo di ricerca di questa tesi di dottorato è quello di sviluppare una valutazione ambientale ed economica delle NBS per territori altamente urbanizzati basata su logiche e modelli che hanno alla base i servizi ecosistemici, l'ecologia urbana e paesaggistica e degli approcci di approcio life cycle. Questo quadro di valutazione combinato aiuterebbe a capire meglio se le NBS sono costo effetive e se contribuiscono a uno sviluppo resiliente e sostenibile. Questo scopo di ricerca è sviluppato secondo quattro obiettivi specifici. Il primo obiettivo corrisponde alla caratterizzazione delle NBS in relazione ai contesti urbani e alle problematiche che possono aiutare ad affrontare o mitigare. Per raggiungere questo obiettivo è stata sviluppata una revisione critica dell letteratura sullo studio della relazione tra NBS, servizi ecosistemici (ES) e sfide urbane (UC). Come risultato principale, si ottiene un grafico delle relazioni causa-effetto plausibili tra NBS, ES ed UC. Il grafico rappresenta un primo passo per supportare la pianificazione urbana sostenibile, passando dai problemi (es. UC) alle azioni (es. NBS) alle risoluzioni (es. ES). Il secondo obiettivo corrisponde alla definizione di un set di metodi e indicatori di valutazione biofisica e monetaria adeguate per valutare il valore della NBS in contesti urbanizzati. Per raggiungere questo obiettivo, viene sviluppata una revisione dei metodi esistenti sulla valutazione dei servizi ecosistemici, l'analisi dei costi del ciclo di vita e la valutazione del ciclo di vita. La revisione tiene conto di vincoli specifici come la facilità d'uso e la disponibilità dei dati. Alla fine, sono stati selezionati potenziali metodi e indicatori, che saranno successivamente integrati nel quadro di valutazione combinato. Il terzo obiettivo corrisponde alla progettazione del quadro di valutazione combinato, integrando metodi di valutazione del ciclo di vita, ecologia paesaggistica / urbana e servizi ecosistemici che quantifica il valore ambientale ed economico della NBS informando sull'efficacia in termini di costi del suo intero ciclo di vita. Per raggiungere questo obiettivo, prima viene sviluppato un quadro concettuale. Da esso, viene sviluppato un modello di dinamica di sistemi per calcolare i servizi (e disservici) ecosistemici, il quale è interrelazionato con un metodo di valutazione life cycle. Questa valutazione combinata viene testata con un tipo di NBS pertinente (foresta urbana) in un caso di studio nell'area metropolitana di Madrid. Il quarto obiettivo è lo sviluppo di uno strumento di supporto decisionale (DSS) che integri il quadro di valutazione come parte dei processi di progettazione iterativa nella pianificazione urbana e nella progettazione del paesaggio. Il DSS intende migliorare l'interrelazione tra scienza, politica e pianificazione / progettazione. Per raggiungere questo obiettivo è stato sviluppato Nbenefit$® un prototipo di DSS online per la valutazzione NBS di facile uso. Il prototipo DSS fornisce all'utente una forma semplice per quantificare multipli ES e costi (internalizatti o no) durante l'intero ciclo di vita (implementazione, vita operativa e fine vita) del NBS. In conclusione, questa tesi ha contribuito alla caratterizzazione di NBS e alla sua valutazione ambientale ed economica per informare i processi di pianificazione urbana e progettazione del paesaggio, consentendo decisioni più informate.
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Augustine, Starrlight. "Metabolic programming of zebrafish, Danio rerio uncovered : Physiological performance as explained by Dynamic Energy Budget Theory and life-cycle consequences of uranium induced perturbations." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4708/document.
Full textAbstract:
Ce travail de thèse s'est intéressé aux effets de l'uranium appauvri (U) sur le poisson zèbre, Danio rerio. L'hypothèse de travail majeure est que les effets de l'U peuvent se traduire par des modifications du métabolisme. Par conséquent nous avons caractérisé la performance physiologique par le biais de la théorie des bilans d'énergie dynamique (DEB) car c'est la seule théorie qui quantifie simultanément l'ingestion, l'assimilation, la croissance, la reproduction, la maturation, la maintenance et le vieillisse¬ment au cours du cycle de vie entier à des niveaux de nourriture variable. Un modèle DEB a ainsi été construit et a permis de quantifier et de prédire la manière dont la performance physiologique du poisson zèbre dépend de son niveau de nutrition (et de la température). Nous avons montré que le développement s'accélère après la naissance jusqu'à la métamorphose où l'accélération cesse. De plus les coûts de maintenance somatique sont très élevés.Un module spécifiant la toxico-cinétique de l'U, chez un individu qui se nourrit, croit et se reproduit, a été incorporé dans le modèle DEB. Le modèle a été appliqué aux données de toxicité (publiés et acquis pendant la thèse) afin de découvrir quel processus est affecté par l'U. Les résultats montrent qu'à partir de 0 nM, l'U augmenterait les coûts de croissance et diminuerait l'assimilation et/ou augmenterait le coût de la maintenance somatique. Nous n'avons pas pu détecter d'effets notables sur la maturation. Une étude histologique révèle que l'U altère l'intégrité de la paroi intestinale et pourrait perturber l'homéostasie des interactions hôte-bactériesThe aim of this dissertation is to characterize the toxicity of depleted uranium (U) on the metabolism of zebrafish, Danio rerio. The underlying hypothesis of this work is that effects of U show up as effects on the metabolism of the individual. Consequently, we characterized physiological performance using Dynamic Energy Budget (DEB) theory since it is the only theory which simultaneously specifies ingestion, assimilation, growth, reproduction, maturation, maintenance and ageing over the whole life-cycle at varying food availability. Thus a DEB model was built which quantifies and predicts how the physiological performance of zebrafish relates to food level (and temperature). We showed that development accelerates after birth until metamorphosis after which acceleration ceases. Furthermore, somatic maintenance costs are very high.A module specifying toxico-kinetics of U in a feeding, growing and reproducing individual was incorporated into the DEB model. The model was then applied to toxicity data (from the literature or acquired during this thesis) in order to determine which processes are affected by U. Our results show that, from 0 nM onwards, U increases costs for growth and either increases somatic maintenance or decreases assimilation. We were unable to detect effects on maturation. A histological study showed that U alters histology of the gut wall and may perturb host-microbe homeostasis. By accounting for differences in initial conditions between individuals we were able to explain a number of seemingly contradictory results. The take home message is: observations on individuals should not be averaged for groups of individuals
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Ahrens, Kayayan Vartan. "Life cycle assessment comparison of two residential buildings using wood and concrete in Sweden : A Global Warming Potential comparison between material choices within Attacus Stomsystem AB chain of production with considerations for temporal dynamics." Thesis, Mittuniversitetet, Institutionen för ekoteknik- och hållbart byggande, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-41963.
Full textAbstract:
Using the case study of a six-floor residential building with 4254 m2 living area and its supply chains, service life and disposal in the Swedish context, a conventional life cycle assessment focused on Global Warming Potential was carried out. The assessment is incomplete because sections B1-B5 were not taken into consideration. A Time Adjusted Warming Potential was also calculated from the conventional results to address the dynamics in the long service life of wooden and concrete buildings. The results are 358 kg CO2 eq/m2 and 175 kg CO2 eq/m2 for concrete and wood, respectively. Of the alternatives analyzed, both using slag concrete and combining the materials in hybrid buildings were shown to have significant reduction potential. The dynamic analysis did not change the overarching results because they strengthened the existing differences. Temporal recalculations were responsible for substantial difference, between 11% (full life cycle for concrete building) and 55% (post-use carbonation) in the categories which apply. This thesis therefore argues for these dynamic issues to be further addressed in the field of LCA methodology. Taking time of emission into consideration leads significant difference in the results particularly in products which have longer life cycles such as the construction industry. These should be addressed in a systematic way.2020-06-05
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Augustine, Starrlight. "Metabolic programming of zebra fish, Danio rerio, uncovered; physiological performance as explained by Dynamic Energy Budget theory and life cycle consequences of uranium induced perturbations." Phd thesis, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00761088.
Full textAbstract:
L'objectif de ces travaux de thèse était de caractériser la toxicité de l'uranium sur le métabolisme du poisson zèbre, Danio rerio. Puisque les effets de l'uranium se traduisent par des modifications de la performance du métabolisme, la question suivante se pose: que savons-nous du métabolisme du poisson zèbre témoin? Très peu de chose. En effet, nos connaissances à ce sujet sont assez limitées en dépit d'un grand nombre de travaux sur le développement de ce poisson. C'est pourquoi les trois premiers chapitres de ce manuscrit sont dédiés à la caractérisation du métabolisme témoin du Danio. J'ai utilisé la théorie des bilans d'énergie dynamique (DEB) pour procéder à cette caractérisation; à l'heure actuelle c'est la seule théorie qui quantifie l'ingestion, l'assimilation, la croissance, la reproduction, la maturation, la maintenance et le vieillissement pendant le cycle de vie entier d'un organisme. L'effet de l'uranium sur l'organisme implique un effet sur au moins une des processus cités ci-avant. Étant donné que la longévité du poisson zèbre est d'environ quatre ans et demi, et que l'intensité des effets liés à un stress chimique est inversement proportionnel à la taille, nous avons centré nos efforts sur les stades de vie précoces (embryon, juvénile et reproduction adulte). De surcroît, les stades de vies précoces semblent plus sensibles aux effets de l'uranium surtout au niveau des effets sur la croissance. D'importants progrès ont été réalisés dans le domaine de la quantification du développent, de la croissance et de la reproduction du poisson zèbre. Il s'est avéré que le poisson zèbre accélère son développent après la naissance (c'est-à-dire l'instant où l'individu commence à se nourrir), jusqu'à la métamorphose, où l'accélération cesse. Ce processus a été constaté chez d'autre espèces de poissons, mais pas toutes. Une autre conclusion surprenante était que la maintenance somatique est beaucoup plus élevée que la valeur typique d'un poisson. Nous n'arrivons pas encore à expliquer pourquoi. De plus nous avons découvert que les détails sur la physiologie reproductive sont importants pour caractériser les effets de l'uranium: chez l'adulte les ressources allouées à la reproduction sont stockées dans un compartiment où siègent les processus de préparation de "batch " d'œufs (=buffer de reproduction). Il est donc important de comprendre ce processus pour comprendre comment le poisson zèbre élimine l'uranium via les œufs.
La théorie DEB spécifie que l'individu atteint un stade de développement à un niveau de maturité donné. Selon la température et/ou la nourriture, ce niveau de maturité peut être atteint à des tailles ou des âges différents. Nous avons élargi le concept pour inclure tous les stades de développement (définis sur la base de critères morphologiques) publiés dans les atlas de développement. Ce travail nous a permis d'expliquer par la théorie DEB à présent la variabilité en termes de taille et d'âge.
Dans le but de tester si la théorie DEB peut expliquer des perturbations au niveau de la maturation, nous avons étudié le développement de deux espèces de grenouilles taxonomiquement proches et de taille similaires. Une des espèces possède un développement typique comprenant un stade embryonnaire, un stade têtard qui se nourrit et puis un stade juvénile avec la morphologie typique d'une grenouille. Par contre la deuxième espèce témoigne d'une accélération du développement après l'éclosion mais avant la naissance- qui correspond au stade de développement où l'individu commence à se nourrir. Cette accélération est trahie par une augmentation de la respiration et un retard de la croissance avec au final une diminution de la taille à chaque stade de développement par rapport à la première espèce. Cette accélération s'estompe après la métamorphose (le moment où les jeunes grenouilles quittent l'eau). Toutes les différences entre les deux types de développement ont été expliquées par la théorie DEB en considérant qu'un seul paramètre changeait temporairement de valeur: la fraction de la réserve mobilisée vers la croissance et la maintenance somatique. La conclusion est que les perturbations observées au niveau de la maturation et de la variabilité de l'âge et la taille entre les différents stades de développement soutiennent empiriquement la façon que la théorie DEB incorpore la maturation.
Non seulement notre étude requérait une quantification détaillée de la maturation, mais elle requérait aussi la prise en compte de périodes (prolongées) de jeune, et ce plus particulièrement pour les stades précoces. Selon la théorie DEB la maintenance est alimentée avec l'énergie mobilisée de la réserve. Dès lors que la nourriture devient rare ou disparait cette dernière ne suffit plus pour alimenter la maintenance somatique. Nous avons détaillé ce cas de figure en modélisant le lien entre les processus de rajeunissement et d'amaigrissement extrême et la probabilité de survie. Les prédictions du modèle sont en accord avec les trajectoires de survie de larves obtenues en conditions de laboratoire. Certaines poissons libèrent plus d'un million d'œufs par événement de ponte et pourtant, si la dynamique de la population est stable, à chaque génération chaque poisson n'est remplacé que par un seul individu. Le processus de survie des larves représente une grande énigme irrésolue dans le domaine de la dynamique de populations de poisson.
Par le biais de ces travaux de doctorat, nous disposons à présent d'un outil permettant de comprendre, et de prédire, la manière dont la performance physiologique du poisson zèbre dépend de son niveau de nutrition. Le modèle a été utilisé pour détecter les modifications induites par l'uranium sur la performance physiologique d'un individu exposé par rapport à celle du témoin. A cette fin, nous avons développé un modèle dynamique qui spécifie la manière dont l'uranium s'accumule et s'élimine chez un individu qui se nourrit, grandit et se reproduit. Nous avions imaginé que l'uranium pourrait affecter le système immunitaire ainsi que d'autres mécanismes de défense cellulaire (e.g. système antioxydant). Selon la théorie DEB, l'allocation des ressources à la maturation comprend une fraction fixe de la réserve mobilisée auquel est soustrait le coût de maintenance de la maturité. Notre idée est que les coûts du système immunitaire et de défense cellulaire contribuent à la maintenance de la maturité. Si l'uranium augmentait les coûts de ce dernier alors la maturation ralentira, ainsi j'ai porté une attention soutenu aux taux de maturation.
Nous avons montré que l'uranium altère l'histologie de la paroi intestinale (acteur majeure dans l'assimilation des nutriments) et pourrait potentiellement modifier l'homéostasie des interactions hôte-bactérienne (acteur majeur dans l'assimilation et l'immunité inné). De plus nos travaux suggèrent que l'uranium augmenterait les coûts de synthèse de la structure et diminuerait l'assimilation et/ou augmenterait le coût de la maintenance somatique. Chose étonnante, malgré ce que nous pensions, nous n'avons pas pu détecter d'effets notables sur la maturation à ces faibles concentrations. Puisque la maturation interagit avec la croissance, la reproduction et la maintenance, je considère néanmoins que les travaux que j'ai pu mener sur la maturation sont pertinents. La toxicité de l'uranium est telle que les effets sur le coût de la synthèse de la structure et de la maintenance somatique sont estimés proches de 0 nM d'uranium dans l'eau.
Un résultat très important se dégageant de ces travaux est que la condition des poissons (structure, maturité, réserve, buffer de reproduction, stade de préparation des "batch") au début de l'expérience dépend de l'individu et conditionne la réponse de celui-ci au stress pendant (toute) l'expérience. Ce problème s'aggrave lorsque nous travaillons avec des poissons zèbres adultes car la contribution de la masse du buffer de reproduction par rapport à la masse totale diffère de manière important entre chaque individu. Ceci affecte alors non seulement les trajectoires de masse dans le temps, mais aussi la concentration interne, car la reproduction représente une voie importante d'élimination de l'uranium. La quantité totale de réserve (à savoir : réserve + buffer de reproduction) conditionne la sévérité de l'effet toxique contribuant ainsi à la variabilité dans les données. En prenant en compte les différences entre les conditions initiales de chaque individu, j'ai pu expliquer les résultats contradictoires publiés dans la littérature ainsi qu'expliquer mes propres résultats sur les effets de l'uranium. La leçon à retenir est que des données acquises sur des individus ne devraient pas être moyennées sur des groupes d'individus.
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Guidani, Beatrice. "Sviluppo di una Piattaforma Multi-decisionale per il controllo di flussi e processi di filiere di produzione e distribuzione agro-alimentari." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textAbstract:
Le reti logistiche agroalimentari sono sistemi complessi composti da molteplici attori. La natura del prodotto fa sì che le filiere debbano essere particolarmente attente alle condizioni ambientali di umidità, temperatura, e al tempo che la merce impiega per raggiungere la tavola.
L’obiettivo della tesi è la progettazione di una piattaforma decisionale in LAbVIEW per il controllo e l’analisi di filiere agroalimentari basata su un modello entità-relazione.
La piattaforma è stata progettata seguendo i principi della programmazione ad oggetti ed ha una visione allargata, ponendo all'interno dei confini del sistema l'attività agricola, attraverso il calcolo della produttività del campo e del periodo di raccolta. In questo modo è possibile osservare le dinamiche che si generano nel disaccoppiamento push-pull che avviene tra il raccolto e gli ordini emessi dai retailer. Vengono anche considerate le esternalità di rete attraverso la misurazione dello spreco di campo e di filiera, e il calcolo degli impatti ambientali e dello sfruttamento delle risorse naturali durante il trasporto e le attività di trasformazione di filiera.
La performance della rete viene misurata attraverso una serie di indicatori sia globali, sia legati a una specifica entità che fa parte del sistema, rendendo l'applicativo facilmente adattabile a molte applicazioni pratiche.
Infine viene presentato un caso studio sulla filiera della patata per evidenziare le potenzialità del simulatore.