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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

A Performance Evaluation Between Low-Carbon Funds and Traditional Funds / Skillnader i avkastning mellan klimatsmarta fonder och traditionella fonder

Skaredotter, Erika January 2021 (has links)
Several organisations and regulators around the globe are recognising warming as a systematic financial risk and investors have increasingly focused on assessing climate-change threats to their assets. In 2018, Morningstar launched a new designation for funds that take global warming into consideration, also called low-carbon funds. This thesis aims to provide relevant insight about the differences in performance and net capital inflow between low-carbon funds and traditional funds on the European market. Furthermore, with the help of statistical regression it was investigated whether low-carbon funds are less sensitive to price changes in different energy and environmental products, such as fossil fuels, electricity and carbon emission allowances, compared to traditional funds. The results suggest that low-carbon funds have been receiving greater compounded annual returns compared to traditional funds during 2018-2020. Furthermore, the annual returns were compared for each fund before- and after becoming a low-carbon fund. The results indicate that it has been more likely for funds to receive greater returns as they became accounted as low-carbon funds. In contrast, any significant difference in net capital inflows between low-carbon funds and traditional funds could not be verified. Finally, it was concluded that the price changes of the included energy and environmental products had no significant impact on the funds' returns. / Organisationer och tillsynsmyndigheter världen över ser den globala uppvärmningen som en systematisk finansiell risk och investerare har i allt högre grad fokuserat på att analysera dessa klimathot i sina tillgångar. År 2018 lanserade Morningstar en ny beteckning för fonder som tar hänsyn till den globala uppvärmningen, så kallade klimatsmarta fonder. Detta examensarbete har som mål att ge relevant information om de skillnader som råder i avkastning och kapitalinflöde mellan klimatsmarta fonder och traditionella fonder på den Europeiska marknaden. Med hjälp av statistisk regression undersöktes huruvida de klimatsmarta fonderna är mindre känsliga för prisförändringar hos olika energi- och miljöprodukter, såsom fossila bränslen, elektricitet och utsläppsrätter, jämfört med traditionella fonder. Resultaten tyder på att klimatsmarta fonder har haft en högre årlig avkastning jämfört med traditionella fonder under 2018-2020. Dessutom jämfördes den årliga avkastningen för varje fond före och efter det att den ansågs vara klimatsmart. Resultaten indikerar att det har varit mer sannolikt för fonder att få en högre avkastning när de klassifceras som klimatsmarta fonder. Inga signifikanta skillnader mellan klimatsmarta fonder och traditionella fonder kunde påvisas hos kapitalinflödet. Avslutningsvis drogs slutsatsen att prisförändringarna på de inkluderade energi- och miljöprodukterna inte hade någon betydande inverkan på fondernas avkastning.
132

The effectiveness of European embassies' climate diplomacy with the USA and China

Buchmann, Katrin Annika January 2016 (has links)
This dissertation focuses on public diplomacy efforts targeted at persuading other countries to strengthen their domestic and international climate change policies. While previous research on climate diplomacy has addressed the global negotiations extensively, the role of embassies and the interplay between diplomats, their partners and the instruments and storylines they employ, has so far not received the scholarly attention it deserves. This is despite the fact that such behind-the-scenes outreach is one of the most promising tools available to engage other states. The dissertation aims to fill this literature gap by examining climate public diplomacy conducted by embassies and consulates of four EU states: the UK, Germany, Sweden and Denmark. The European Union, and these states in particular, were chosen because they have sought to portray themselves as leaders in tackling climate change while undertaking extensive climate diplomacy. The United States and China were chosen as target states since they have been the main focus of EU climate diplomacy, due to their position as the two largest aggregate contributors to climate change. The dissertation addresses public diplomacy in the field of climate change applied to both the federal/national and subnational levels of governance of these states. The main research question tackled by this dissertation is: What role do embassies and consulates play in climate diplomacy, and how effective is this diplomacy? In answering this, the research focuses on identifying environmental discourses and framings of climate change employed by embassies/consulates for different audiences, and assesses the impact of these frames. A central finding was a strong trade and growth orientation of climate diplomacy. The diplomatic network identified industry, especially fossil-fuel intensive businesses, as allies. Some companies that were embassy partners supported climate denial behind the scenes.
133

Carbonatation de bétons à forts taux de substitution du ciment par des additions minérales / Carbonation of concretes with high substitution of cement by mineral additions

Younsi, Akli 23 November 2011 (has links)
Le ciment est la principale source des impacts sur l’environnement de l’utilisation du matériau béton. Afin d’optimiser ce dernier d’un point de vue environnemental, il est nécessaire de réduire son dosage en ciment. Cela peut être entrepris en remplaçant une partie du ciment par des additions minérales lors de sa fabrication.Ces travaux de thèse visent à étudier les phénomènes physico-chimiques ayant lieu lors du processus de carbonatation de bétons à forts taux de remplacement du ciment par des additions minérales ainsi que leur résistance à ce type d’attaque.Une campagne expérimentale a été menée sur des bétons de référence préparés à base de ciments courants et sur des Écobétons préparés en substituant une partie du ciment par des cendres volantes ou du laitier de haut-fourneau. Les différentes études menées portent sur la durabilité des Écobétons vis-à-vis de la carbonatation, sur l’équivalence de performances des Écobétons avec celles des bétons de référence, et sur les paramètres de composition et de microstructure contrôlant la cinétique de carbonatation. La carbonatation a été étudiée en conditions accélérées et naturelles. Les résultats montrent que les Écobétons à forts taux de substitution du ciment par des cendres (50 %) ou du laitier (75 %) pourraient remplacer, dans certains cas, les bétons conformes à la norme en vigueur.En complément à l’étude expérimentale, des simulations numériques du couplage hydratation/séchage ont été menées en vue de déterminer l’effet du séchage sur les propriétés contrôlant la cinétique de carbonatation accélérée des bétons étudiés (la porosité, la quantité de Portlandite et le degré de saturation en eau liquide). Les résultats montrent que la cinétique de séchage augmente avec le taux de substitution du ciment par des additions. Ils remettent aussi en cause la pertinence du préconditionnement des échantillons lors de l’essai de carbonatation accélérée mené selon la norme française XP P 18-458 actuellement en vigueur. / Cement is the main source of environmental impacts of concrete use. It is thus recognized that the most pragmatic solution for minimizing environmental impacts of concrete is the reduction of the cement content. This could be achieved by replacing a part of cement by mineral additions such as fly ash or blast-furnace slag during concrete mixing.The present work aims at studying the physico-chemical phenomena occurring during the process of carbonation of concrete mixtures with high substitution rates of cement by mineral additions and their resistance against this type of attack.An experimental campaign was conducted on reference concrete mixtures prepared with common cements and on other concrete mixtures, called “Écobétons” (Green concretes), prepared by replacing a part of cement by fly ash or blast-furnace slag. The study focused on the Écobétons durability, especially their resistance against carbonation, on the equivalence of Écobétons performances with the reference mixtures performances and on the composition and microstructure parameters controlling the kinetics of carbonation. Carbonation has been studied in natural and accelerated conditions. The results show that Écobétons mixtures with high substitution rates of cement by fly ash (50 %) and blast-furnace slag (75 %) could replace, in some cases, concretes that are in accordance with the current standard.In addition to the experimental study, numerical simulations of the coupling between hydration and drying were conducted in order to determine the effect of drying on the properties controlling the accelerated carbonation kinetics of the studied concrete mixtures (porosity, Portlandite content and water saturation degree). The results show that the kinetics of drying increases with the degree of substitution of cement by mineral additions. They also question the relevance of the preconditioning of the samples during accelerated carbonation test conducted according to the French standard XP P 18-458.
134

國內推動低碳旅遊之研究─以台南市古蹟旅遊為例 / Research on domestic impetus low-carbon tourism - take Tainan heritage tourism as the example

徐仙如, Hsu, Shien Ju Unknown Date (has links)
近年來天災地變頻傳,溫室效應導致全球暖化現象,有鑒於此,全球湧起節能減碳浪潮,低碳旅遊亦應運而生。根據聯合國氣候變遷小組之評估報告,旅遊業對氣候變遷影響重大,人為之溫室氣體排放是肇致氣候變遷異常之主因,如何兼顧日益蓬勃發展之旅遊業與有效抑止二氧化碳排放量之增加,係各國刻不容緩的課題。 台南市以府城古都聞名,轄內古蹟觀光旅遊為其重要收入來源,本研究以市府預計推展古蹟低碳旅遊計畫之相關利害關係人為研究對象,並以訪談法瞭解其需求與對市府之期待。 本研究結果指出台南市古蹟旅遊存有僅實施少數不實用之環保措施、民眾尚未養成搭乘大眾運輸工具習慣、既有街道巷弄過於狹小、居民發展心態矛盾與缺乏減少使用私人運具之誘因、綠色認證制度叫好不叫座、古蹟導覽人員培訓制度簡陋等現存之困境與瓶頸、以及民眾與市府間認知之落差,並對市府提出現有古蹟區軟硬體設備設施之改善與提升、加強產業綠色認證制度之實用性、積極發展古蹟低碳旅遊多元面貌、厚實古蹟文化園區內涵,加強市府行銷能見度、建議逐步養成民眾搭乘大眾運輸使用習慣、型塑台南成為亞洲阿姆斯特丹等六項建議方案。 / In recent years the natural disaster and diastrophism happen frequently, the greenhouse effect caused the global warm phenomenon, therefore, the whole world to surge the energy conservation to reduce the carbon tide, the low-carbon tourism also arises with the tide. According to the Intergovernmental Panel on Climate Change assessment report, the tourism is significant to the climate vicissitude influence, the human is initiates for it greenhouse gas emissions sends the climate vicissitude exceptionally principal factor, how gives dual attention to day by day tourism of the vigorous development and restrains increase effectively the carbon dioxide withdrawal, is the various countries' urgent topic. In Tainan is well-known take the prefectural city ancient capital, governs the heritage site sightseeing tourism as its important source of income, this research by the municipal government estimated promotes correlation of stakeholders of study the heritage low-carbon tourism plan, and understands their demands and to the municipal anticipations for Tainan city government. Research findings pointed out the Tainan heritage tourism extant difficulties and the bottleneck, as well as between the populace and the municipal government dropping variance of the cognition, and to the municipal government proposed improvement of and the promotion the existing heritage area soft and hardware equipment facility, usability of the enhancement industry green authentication system, develops the heritage low-carbon tourism multi-dimensional appearance, the thick heritage culture garden area connotation positively, the enhancement municipal government sells the visibility, fosters the populace to travel by the populace gradually to transport the use custom, models Tainan to become the Asian Amsterdam and so on six suggestion program.
135

Voltage balancing on three-phase low voltage feeder

Li, Yun January 2015 (has links)
Voltage imbalance in low voltage (LV) networks is expected to deteriorate as low carbon technologies, e.g. electric vehicles (EVs) and heat pumps (HPs) are increasingly deployed. The new electrical demand attributable to EVs and HPs would increase the voltage magnitude variation, increasing the possibility of voltages moving outside the statutory LV magnitude limits. Moreover, the single-phase nature of EVs and HPs, which will be connected via a single-phase 'line & neutral' cable to a 3-phase four-wire LV mains cable buried beneath the street, further entangles this voltage management problem; the non-balanced voltage variations in the three phases boost the levels of voltage imbalance. Excessive voltage imbalance and magnitude variation need to be mitigated to limit their adverse effects on the electric network and connected plant. The voltage imbalance in LV networks is conventionally reduced by reinforcing the network, generally at a high cost. Some modern methods for voltage imbalance mitigation have been introduced in recent years. The power electronic converter based methods are inadequate due to the generation of harmonics, significant power losses and short lifetime. Besides, automatic supply phase selection and smart EV charging rely on an advanced smart communication system, which currently is not available. This project aims to develop alternative solutions that mitigate the voltage imbalance seen in LV networks. A voltage balancing method based on Scott transformer (ST) is proposed. This method does not generate harmonics and is independent of the smart communication system. Computer simulations demonstrated the proposed method is able to convert a non-balanced 3-phase voltage into a balanced 3-phase voltage at either a point on the LV feeder or a 3-phase load supply point with the predefined voltage magnitude. Besides, a physical voltage balancing system was created based on the proposed method and it was tested in an LV network in the laboratory. The test results show the balancing system is capable of maintaining a low level of voltage imbalance on the LV feeder by rapidly compensating for the voltage rises and sags caused by single-phase load variations. This voltage balancing method is a potential solution for the network utilities to accommodate the significant penetration of low carbon technologies without breaching the network voltage limits. The impact of EVs and HPs on the LV network voltages is investigated based on a Monte Carlo (MC) simulation platform, which comprises a statistical model of EV charging demand, profiles generators of residential and HP electrical demand, and a distribution network model. The MC simulation indicates the impact of EVs and HPs is related to their distribution; when more than 21EVs and 13HPs are non-evenly distributed on a 96-customer LV feeder, the voltage limits are likely to be violated. Moreover, the effectiveness of the ST based voltage balancing method and the demand response based TOU tariff, implemented either alone or together, in mitigating the impact of EVs and HPs is investigated based on the established MC simulation platform. The results indicate the ST based balancing method alone is able to completely mitigate the voltage limit violations regardless of the penetration levels of EVs and HPs. Moreover, using both of the two investigated methods further enhances the balancing effectiveness of the ST based voltage balancing method.
136

Sustentabilidade e competitividade na cadeia logística: redução de emissões de gases de efeito estufa com o uso do modal de transporte cabotagem: estudo de caso

Barbosa, Luciane Pereira 28 September 2018 (has links)
Submitted by LUCIANE PEREIRA BARBOSA (lpb1404@hotmail.com) on 2018-10-26T16:58:52Z No. of bitstreams: 1 TRABALHO APLICADO - MPGC - LUCIANE P BARBOSA - VERSAO FINAL rev1.pdf: 1890693 bytes, checksum: 3bdd2519e40dc4e33254c14cdccfdf8d (MD5) / Approved for entry into archive by Simone de Andrade Lopes Pires (simone.lopes@fgv.br) on 2018-10-27T00:00:23Z (GMT) No. of bitstreams: 1 TRABALHO APLICADO - MPGC - LUCIANE P BARBOSA - VERSAO FINAL rev1.pdf: 1890693 bytes, checksum: 3bdd2519e40dc4e33254c14cdccfdf8d (MD5) / Approved for entry into archive by Suzane Guimarães (suzane.guimaraes@fgv.br) on 2018-10-29T12:28:14Z (GMT) No. of bitstreams: 1 TRABALHO APLICADO - MPGC - LUCIANE P BARBOSA - VERSAO FINAL rev1.pdf: 1890693 bytes, checksum: 3bdd2519e40dc4e33254c14cdccfdf8d (MD5) / Made available in DSpace on 2018-10-29T12:28:14Z (GMT). No. of bitstreams: 1 TRABALHO APLICADO - MPGC - LUCIANE P BARBOSA - VERSAO FINAL rev1.pdf: 1890693 bytes, checksum: 3bdd2519e40dc4e33254c14cdccfdf8d (MD5) Previous issue date: 2018-09-28 / Este trabalho tem por objetivo levantar, analisar e divulgar a sustentabilidade ambiental no transporte por cabotagem na operação de logística de uma empresa fabricante de eletrodomésticos. O método usado foi um estudo de caso único, sobre a sustentabilidade no transporte por cabotagem, focando seus impactos na emissão de CO2 na cadeia logística das operações da empresa no Brasil. Devido às dimensões continentais de nosso país, a cadeia logística é um grande desafio para atender às demandas de clientes com rapidez mantendo a sua competitividade e segurança. Dentro deste contexto a partir de 2015 a empresa intensificou o uso do transporte marítimo de cabotagem visando a redução de custos com seguros e evitar problemas com roubo de cargas. Porém uma externalidade positiva passou despercebida, que é a redução nas emissões de CO2 devido ao uso deste modal. Uma das metas em Sustentabilidade da empresa é minimizar o seu impacto climático, impedindo a liberação de 25 milhões de toneladas de dióxido de carbono e seus equivalentes (CO2e) ao longo de 15 anos, entre 2005 e 2020, e um dos caminhos é promover o uso de modais de transporte mais eficientes. Na revisão da literatura evidenciou-se que as emissões de CO2 por transporte rodoviário podem ser até 10 vezes maiores que o transporte marítimo para um mesmo volume de produto transportado (SCHMIED e KNÖRR, 2012). Portanto, esta pesquisa foi realizada através da análise exploratória sobre os dados dos embarques realizados pela empresa no período de janeiro/2015 a agosto/2018 e cálculo do impacto das emissões de CO2 dos respectivos embarques, adotandose o método proposto na norma CEN - EN 16258 – “Metodologia para o cálculo e declaração do consumo de energia e das emissões de gases com efeito de estufa dos serviços de transporte”. Esse trabalho visa contribuir para o estudo sobre sustentabilidade em cadeias logísticas e trazer maior clareza aos gestores sobre os impactos positivos à competitividade e ao meio ambiente ao adotar transportes alternativos ao tradicional rodoviário. / This work analyzes and propagates the sustainability of cabotage transport in the logistics operation of a home appliances manufacturing company. The research method was a case study, unique and holistic, about cabotage transport and its impacts on CO2 emissions in the logistics chain of the company's operations in Brazil. The continental dimensions of this country lead to a significant challenge in the logistics chain to meet the demands of customers, while quickly maintaining its competitiveness and safety. In this context, starting in 2015, the company intensified the use of cabotage shipping in order to reduce insurance costs and avoid problems with cargo theft. Nevertheless, a positive externality went unnoticed: the reduction in CO2 emissions due to the use of this modal. One of the company's sustainability goals is to minimize its climate impact by preventing the release of 25 million tonnes of carbon dioxide and its equivalents (CO2e) over 15 years between 2005 and 2020, and one way is to promote the use of more efficient transport modes. In the review of the literature, it has shown that CO2 emissions by road transport can be up to 10 times greater than maritime transport for the same volume of transported product (SCHMIED and KNÖRR, 2012). Therefore, this research was carried out through the exploratory analysis on the data of shipments made by the company from January/2015 to August/2018 and calculation of the impact on CO2 emissions of the respective shipments, adopting the method proposed in CEN- EN 16258 - "Methodology for calculating and reporting energy consumption and greenhouse gas emissions from transport services". This paper aims to contribute to the study on sustainability in logistics chains and to bring greater clarity to managers about the positive impacts in competitiveness and environment when adopting an alternative mode of transport to the traditional road transport.
137

Transition énergétique et géographie : le photovoltaïque au sol dans le sud de la France / Energy transition and geography : the photovoltaic ground in the south of France

Duruisseau, Kévin 18 November 2016 (has links)
Amorcée en 2002 avec la mise en place d’un régime financier d’encadrement basé sur un système de tarifs de rachat de l’électricité, la politique photovoltaïque au sol (PVS) vient enrichir les politiques énergie-climat françaises, devenues depuis des politiques publiques de transition énergétique. Ces politiques se déploient dans un contexte d’ouverture à la concurrence associée à la libéralisation des marchés de l’électricité, de fractionnement des moyens de production et de dévolution croissante de compétences « électriciennes » aux acteurs territoriaux publics favorisant une multiplication et une diversification des acteurs intervenants dans le système électrique français. Ces mutations ont amorcé un processus de territorialisation des EnR et dessinent une nouvelle géographie de l’électricité. Cette thèse interroge la place des territoires dans la transition énergétique, dans une analyse du processus de territorialisation de la politique publique PVS en France, et discute de l’émergence d’une nouvelle géographie de l’électricité. Elle articule une étude de la géographie des unités PVS en activité au 31 décembre 2015 dans les territoires du sud de la France avec une analyse actorielle de la diffusion spatiale de ces nouvelles infrastructures industrielles. Elle propose pour ce faire une typologie des acteurs-initiateurs PVS et une typologie des opérateurs-exploitants PVS permettant de mettre en évidence les nouveaux acteurs électriciens du système électrique français métropolitain. Elle propose plus largement une étude des systèmes de régulation et des jeux d’acteurs à l’œuvre dans les territoires PVS révélant le processus de territorialisation de cette EnR. / Began in 2002 with the establishment of a financial supervisory regime based on a system of feed-in tariffs, the photovoltaic public policy on the ground enriches French energy and climate public policy, which have since become public policies for “low carbon” energy transition. These policies are deployed in a context of openness to competition associated with the liberalization of the European national markets for electricity, means splitting production and increasing devolution of "Electricians" powers to public territorial players favoring multiplication and diversification of actors involved in the metropolitan French electrical system. These changes have initiated a process of territorialization of renewable energy and create a new geography of electricity.This thesis questions the place of the territories in the "low carbon" energy transition, in an analysis of regionalization of public policy photovoltaic ground process in France, and discusses the emergence of a new geography of electricity. It articulates a study of the geography of photovoltaic ground units in operation on 31 December 2015 in the southern territories of France with an actorial analysis of the spatial distribution of these new industrial infrastructures. It proposes to do this a typology of photovoltaic ground initiators-actors and a typology of photovoltaic ground developers-operators to highlight the new electric actors of the metropolitan French electrical system. It offers a wider study of regulatory systems and sets of actors at work in the implementation of photovoltaic ground territories revealing the territorialization process of this renewable energy.
138

Influence of metallurgical phase transformation on crack propagation of 15-5PH stainless steel and 16MND5 low carbon steel / Influence de la transformation de phase métallurgique sur la propagation des fissures de 15-5PH et 16MND5

Liu, Jikai 07 December 2012 (has links)
Cette thèse porte sur l’influence des transformations de phases solide-solide sur la propagation de fissure. On souhaite ainsi mieux comprendre les variations de ténacité en cours de soudage par exemple, ou bien pendant la réparation d’une fissure. Dans ce travail, la ténacité est obtenue à partir de l’intégrale J. Il existe de nombreuses méthodes expérimentales permettant d’obtenir la ténacité critique JIC mais qui sont difficilement applicables pour des essais se déroulant pendant une transformation de phase. C’est pourquoi nous avons proposé une méthode couplant essai mécanique et mesure par corrélation d’images avec de la simulation par éléments finis. Les essais sont réalisés sur de simples éprouvettes plates pré fissurées, faciles à usiner et simple à chauffer par induction. Les essais sont conduits pour différentes températures et jusqu’à rupture. En sus des mesures d’efforts et déplacements de traverse, la corrélation d’images nous fourni également les champs de déplacement sur chaque face de l’éprouvette. Chaque essai est ensuite simulé par éléments finis où la ténacité critique est calculée par la méthode G-Theta au maximum de la charge supportée par l’éprouvette. Les simulations précédentes intègrent les conditions aux limites obtenues par corrélation et le comportement mécanique considéré est celui que nous avons identifié sur des essais de caractérisation. Deux nuances de matériau ont été étudiées avec cette méthode ; l’acier inoxydale 15-5PH ainsi que l’acier ferritique 16MND5. Pour ces deux matériaux, différentes températures d’essai ont été choisies avant, pendant et après la transformation pour effectuer les essais de rupture ainsi que de caractérisation du comportement mécanique. Les résultats de cette étude montrent que la transformation de phase peut avoir un impact non négligeable sur la ténacité. Ainsi, pour le 15-5PH, le taux d’austénite résiduel est un facteur important et les essais pendant la transformation martensitiques montrent que la ténacité critique peut être inférieure pendant celle ci à celle du matériau purement austénitique. Dans le cas du 16MND5, la ténacité est beaucoup plus faible à 600°C (et bainitique) qu’à température ambiante ce qui est assez logique. Par contre, lors du refroidissement, depuis 600° (austénitique) jusqu’à la température ambiante (bainitique), nous avons obtenu une ténacité critique relativement constante. En conclusion, cette étude apporte une solution quant à la mesure de la ténacité critique de matériau pendant des transformations de phases, ce que ne permettent pas forcément les essais normalisés. Pour le 15-5PH, la ténacité critique semble évoluer pendant la transformation martensitique et est assez dépendante du taux d’austénite résiduelle. Il semble par contre que pour le 16MND5, la ténacité critique soit assez peu dépendante de la fraction volumique d’austénite et la valeur obtenue varie peu au cours du refroidissement du matériau depuis 600°C. / Ou study focuses on the effects of phase transformations on crack propagation. We want to understand the changes of fracture toughness during welding. In this work, fracture toughness is expressed by J-integral. There are many experimental methods to obtain the critical toughness JIC but they are impractical for our investigation during phase transformation. That is the reason why we have proposed a method coupling mechanical tests, digital image correlation and finite element simulation. The fracture tests are implemented on pre-cracked single edge notched plate sample which is easy for machining and heat conduct during phase transformation. The tests are conducted at different temperatures until rupture. Digital image correlation gives us the displacement information on every sample. Each test is then simulated by finite element where the fracture toughness is evaluated by the method G-Theta at the crack propagation starting moment found by potential drop method and digital image correlation technical. Two materials have been studied, 15Cr-5Ni martensitic precipitation hardening stainless steel and 16MND5 ferritic low carbon steel. For these two materials, different test temperatures were chosen before, during and after phase transformation for testing and failure characterization of the mechanical behavior. Investigation result shows that metallurgical phase transformation has an influence on fracture toughness and further crack propagation. For 15-5PH, the result of J1C shows that the as received 15-5PH has higher fracture toughness than the one at 200°C. The toughness is also higher than the original material after one cycle heat treatment probably due to some residual austenite. Meanwhile, pure austenite 15-5PH at 200°C has higher fracture toughness than pure martensitic 15-5PH at 200°C. For 16MND5, the result also proves that the phase transformation affects fracture toughness. The as received material has bigger J1C than the situation where it was heated to 600°C. On the other hand, the material at 600°C just before isothermal bainite transformation after the austenitization during cooling process also has higher fracture toughness than the one at 600°C before austenitization. These two conclusions are consistent well with the result of 15-5PH. But the final situation of 16MND5 after one cycle heat treatment has a slightly smaller J1C than the receiving situation. It means that one cycle heat treatment hasn't an significant influence on 16MND5fracture toughness. Conclusions show that one should pay attention to the heating period before austenitization of the substrate material when people do the welding as the higher temperature will bring the lower fracture toughness during this process. While during cooling period, the fracture toughness doesn't change a lot during, before or after the cooling induced phase transformation. Even for 15-5PH, it has a better fracture toughness after the martensite transformation than before.
139

Study on Sustainable Low Carbon Society in Malaysian Regional Development / マレーシアの地方開発における持続可能な低炭素社会に関する研究

SIMSON, Janice Jeevamalar 26 March 2012 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第16790号 / 工博第3511号 / 新制||工||1531(附属図書館) / 29465 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 松岡 譲, 教授 米田 稔, 准教授 倉田 学児 / 学位規則第4条第1項該当
140

Supervisory model predictive control of building integrated renewable and low carbon energy systems

Sadr, Faramarz January 2012 (has links)
To reduce fossil fuel consumption and carbon emission in the building sector, renewable and low carbon energy technologies are integrated in building energy systems to supply all or part of the building energy demand. In this research, an optimal supervisory controller is designed to optimize the operational cost and the CO2 emission of the integrated energy systems. For this purpose, the building energy system is defined and its boundary, components (subsystems), inputs and outputs are identified. Then a mathematical model of the components is obtained. For mathematical modelling of the energy system, a unified modelling method is used. With this method, many different building energy systems can be modelled uniformly. Two approaches are used; multi-period optimization and hybrid model predictive control. In both approaches the optimization problem is deterministic, so that at each time step the energy consumption of the building, and the available renewable energy are perfectly predicted for the prediction horizon. The controller is simulated in three different applications. In the first application the controller is used for a system consisting of a micro-combined heat and power system with an auxiliary boiler and a hot water storage tank. In this application the controller reduces the operational cost and CO2 emission by 7.31 percent and 5.19 percent respectively, with respect to the heat led operation. In the second application the controller is used to control a farm electrification system consisting of PV panels, a diesel generator and a battery bank. In this application the operational cost with respect to the common load following strategy is reduced by 3.8 percent. In the third application the controller is used to control a hybrid off-grid power system consisting of PV panels, a battery bank, an electrolyzer, a hydrogen storage tank and a fuel cell. In this application the controller maximizes the total stored energies in the battery bank and the hydrogen storage tank.

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