• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 838
  • 261
  • 209
  • 72
  • 66
  • 49
  • 30
  • 25
  • 18
  • 12
  • 7
  • 6
  • 5
  • 5
  • 5
  • Tagged with
  • 1770
  • 667
  • 363
  • 287
  • 267
  • 253
  • 211
  • 188
  • 167
  • 164
  • 156
  • 154
  • 151
  • 149
  • 146
  • 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.
711

Energy systems and urban circularity: evaluating the performance of indicators for district heating and cooling systems according to the circular economy principles

Rebola, Joana January 2022 (has links)
The circular economy model has been proposed as a possible strategy for sustainable development in urban areas, implying that its core principles need to be cascaded down to various sectors, including the energy sector. District heating and cooling systems have great potential to enhance circularity on an urban level due to the establishment of synergies between different sectors, the incorporation of renewable energy sources and high efficiency. Indicator-based frameworks are valuable tools for monitoring the transition toward a circular economy. However, no framework to assess circularity in district heating and cooling systems was found. Thus, this study addresses this gap by reviewing currently available indicators used to assess district heating and cooling systems and understanding to what extent they reflect circular economy principles. For this purpose, 27 papers with 271 indicators were assessed against defined criteria related to the circular economy principles. These criteria included transparency, stakeholder engagement, effective communication, ability to track temporal changes, applicability, alignment with circular economy principles, validity and relevance to sustainable development. Afterwards, 89 indicators were selected and classified based on the 10R principle framework. The assessment revealed that the assessed papers cover a wide range of topics and assessment types and that none of the assessed papers fulfils all of the assessment criteria. Moreover, most of the identified indicators connect to the environmental and economic pillars of sustainable development, and the identified indicators focus primarily on the R principles of Reduce and Recover. This study laid the foundation for further research on the relationship between district heating and cooling systems and the circular economy by identifying the understudied areas and highlighting the need to develop tailored indicators to measure circularity in these systems.
712

Office chairs in circular business models

Askew, Robin, Carlberg, Stefan January 2016 (has links)
This is a master’s thesis project of 30 credits written with guidance from the Swedish research institute ICT Viktoria and Industrial Ecology at KTH. This thesis is conducted by two students at KTH, one with a background in Mechanical Engineering and Industrial Ecology and the other with a background in Energy and Environmental Technology. This study focuses on circular economy linked to the furniture industry in Sweden and how the transition from theoretical to practical concepts can be improved. The methods of this thesis consist of three semi-structured interviews, a survey and an analytical comparative literature review. The interviews, survey and literature review is analyzed with the purpose of finding important criteria relevant for office chairs in circular business models. The interviews are performed face-to-face with three different key persons; an office supply manager, a CEO at a refurbishing company and a product manager. The study focuses on product design within the Swedish furniture industry although some aspects regarding circular business models, logistics and psychological values are included. The results are design criteria for office chairs in circular business models and a design evaluation program for the industry built on these. The program, based on multi criteria analysis, can help reduce the gap between theory and practice of how circular economy should be implemented in the industry. By giving early feedback during the design phase on how well an office chair and a company’s structure meet circular economy criteria the authors hope to ease and speed up this transition. The main characteristics of an office chair designed for circular business models are: Durable Easy to service Adaptable Modular Homogeneous material composition in modules Although the transition to circular business models can be a comprehensive process the authors believe that if furniture manufacturers would integrate circular business models for office chairs into their business structure this would be both economically viable and highly beneficial for their environmental profile which can strengthen their position on the market.
713

Promoting Circular Economy By Partial Replacement Of Cement With SCMs : A Review On Wood Ash / Främja cirkulär ekonomi i betongindustrin i Sverige genom att delvis ersätta cement med alternativa bindemedel : En översikt av träaska

Salman, Asal January 2022 (has links)
The European Commission adopted the first action plan for the transition to a circular economy in 2015. As a result, the concrete industry’s goal is for all concrete produced in Sweden to be climate neutral by 2045. Cement production is the third-largest carbon dioxide emitter in Sweden and accounts for 90% of concrete’s carbon dioxide emissions. Thus, to lower the climate footprint of concrete, it is necessary to find alternatives to cement. The potential of the use of wood ash in cement as a supplementary cementitious material (SCM) has been investigated in several studies. Due to Sweden's nature and wood industry, a comprehensive study has been done to investigate the possibility of using wood ash as an SCM in Sweden based on availability and efficiency. This work aims to investigate the obstacles and driving forces that concrete producers face when transitioning to a circular economy by partially replacing cement with new potential SCMs. The aim is also to investigate the availability of wood ash generated in Sweden and account for the potential to be used as an SCM. Qualitative semi-structured interviews with open-ended questions were conducted to determine the obstacles and drivers that concrete producers in Sweden face when converting to a circular economy by partially replacing cement with new potential SCMs. The amount of ash produced in Sweden was estimated based on the value of ash content and the potential annual supply of wood fuels in Sweden. In addition, a literature review was performed to investigate the properties of wood ash. The economic and environmental aspects, as well as the fact that the supply of fly ash and slag is likely to decrease in the future form the main driving forces for concrete producers. The obstacles raised by the correspondents were the availability of SCMs, technical barriers, logistics, and standards. The amount of the annual production of wood ash in Sweden is estimated to be between 851 450 and 1 232 950 tons. The chemical characteristics of wood ash did not meet the requirements according to European standard (EN450-1). However, the reviewed articles indicated a potential for wood ash to be used as a supplementary cementitious material due to the indication of some hydraulic and pozzolanic activities. The combination of fly ash and wood ash in concrete is considered viable due to promising results based on mechanical strength. / EU-kommissionen antog den första handlingsplanen för omställningen till en cirkulär ekonomi 2015. Som ett resultat av detta är betongindustrins mål att all betong som används i Sverige ska vara klimatneutral år 2045. Cementindustrin är den tredje största koldioxidutsläpparen i Sverige och står för 90 % av betongens koldioxidutsläpp. För att sänka betongens klimatavtryck är det nödvändigt att hitta alternativ till cement. Potentialen för användningen av träaska i cement som ett alternativt bindemedel har undersökts i flera studier. Med hänsyn till Sveriges natur- och träindustri har en omfattande studie gjorts för att undersöka möjligheten att använda träaska som alternativ bindemedel i Sverige utifrån tillgänglighet och effektivitet. Arbetet syftar till att undersöka de hinder och drivkrafter som betongföretag möter vidövergången till en cirkulär ekonomi genom att delvis ersätta cement med nya alternativa bindemedel. Syftet är också att undersöka tillgången på träaska som genereras i Sverige och redogöra för potentialen att användas som ett bindemedel. Kvalitativa semistrukturerade intervjuer med öppna frågor genomfördes för att fastställa de hinder och drivkrafter som företag inom betongtillverkning i Sverige möter vid en omställning där cement ersätts delvis med nya bindemedel. Mängden aska som produceras i Sverige har uppskattats utifrån värden på askhalt och den potentiella årliga tillgången på trädbränslen i Sverige. Dessutom har en litteraturöversikt genomförts för att undersöka träaskans egenskaper. Drivkrafterna för en omställning till cirkulär ekonomi hos betongindustrier genom delvis ersättning av cement med nya alternativa bindemedel är de ekonomiska och miljömässiga aspekterna samt det faktum att tillgången på flygaska och slagg riskerar att sjunka i framtiden. Hindren som korrespondenterna tog upp var tillgången till alternativa bindemedel, tekniska barriärer, logistik och standarder. Mängden av den årliga produktionen av träaska i Sverige uppskattas mellan 851 450 och 1 232 950 ton. Kemiska egenskaper hos de undersökta träaskorna uppfyller inte kraven enligt europeisk standard (EN450-1). Litteraturöversikten visar dock en potential för träaska att användas som ett alternativt bindemedel till följd av en viss hydraulisk och puzzolanisk aktivitet. Kombinationen av flygaska och träaska i betong anses lönsam på grund av lovande resultat baserade på mekanisk hållfasthet.
714

Keeping it in the loop : A roadmap to circular economy for NCC / Bibehålla i kretsloppet : En vägbeskrivning för cirkulär ekonomi i svensk byggindustri

Tabrizi, Shanar January 2016 (has links)
Resource efficiency and circular economy (CE) has become increasingly relevant to the Swedish construction company NCC in connection to the plans of demolishing the current head office in Stockholm and building a new head office next to it. NCC wants to investigate how to minimize the negative sustainability implications of bringing down a commercial facility well before its life length has expired, through exploring the possibilities of integrating principles of CE in future planning‐and construction processes. This study seeks to understand how the Swedish construction company NCC could work with decision-making for CE in order to keep their materials in the loop. As the concept of CE is broad there are many options for working with its principles. However, the construction industry is relatively new to these and a list of priorities would therefore be helpful in such an initial phase, as focusing on all would be inefficient and rather daunting. Thus, this study suggests a multi-criteria decision analysis (MCDA) as a tool for decision-making and prioritizing between various approaches to CE. Together with NCC, an MCDA was performed where three different options for working with CE were analysed (Waste as Resource, Circular Design and Circular Business Models). In a focus group, 17 criteria that were relevant to NCC were developed as a basis for analysing the options. These were then defined, scored and weighted to reveal a most preferable option. The MCDA showed that the most preferable approach to CE for NCC is working with circular design, i.e. Design for Deconstruction (DfD), followed closely by measures to increase the rate of reuse and recycling of already existing construction- and demolition waste. However, the sensitivity analysis revealed that if economic criteria received a higher weight, increased reuse and recycling is the most preferable option. MCDA was deemed a helpful decision-making tool for CE principles. While the scoring and weighting is subjective and it is challenging to quantify the criteria, the strength lies in bringing a new and innovative topic on the agenda by gathering key decision-makers in focus groups to discuss and learn. A preliminary study to this thesis was conducted at NCC (Tabrizi, 2015) with the aim of conducting a survey of good examples with regard to development of commercial properties that are designed for flexibility and deconstruction during refurbishment and end‐of‐life. It showed that the challenges relate to the hesitant perception of secondary material, design and construction limitations, the need for material documentation, organization and logistics as well as creating sustainable business models. Key success factors for overcoming these challenges for NCC is working towards better communication and promotion of secondary material through information sharing, building up a knowledge base and internal targets, as well as establishing a consistent work methodology for DfD in order to move NCC towards a circular economy.
715

In-house glove recycling : Eliminating a waste stream with a circular approach

Sjöberg, Axel, Olsson Stjernberg, Johan January 2020 (has links)
Background. Between 2012 and 2017 the plastic supply in Sweden increased by almost 400000 metric tons. In 2017, the hospitals in Sweden contributed to 4550 metric tons of plastic waste, disposable gloves counted for 2100 metric tons, which is 358 million disposable gloves. The majority made in other countries than Sweden, which is not only contributing to a considerable waste stream but also vulnerability when the system is dependent on continuous material supplies. Aim and Purpose. The research aim has been to understand the challenges and opportunities of needs relating to plastic waste flows from the health care sector. From the needs, choose an area to develop an innovative solution that changes the current waste flow into value for the health care sector in Sweden. Method. For this thesis, the researcher has used the Design Research Methodology and the MSPI innovation process. Design Research Methodology has been used to find and validate crucial information about the problem, by the usage of literature research and Unstructured interviews within the research area. MSPI was iteratively used with DRM to design the intended support as well as building the actual support. Results. The final prototype proves that circularity for plastic materials in hospitals is reachable. The Needfinding highlights the need for circularity, regarding both an effective use of the material and the health care’s readiness levels where access to Personal Protection Equipment (PPE) is crucial, especially in times of crisis. Conclusions. During the time of crisis, the COVID-19 pandemic, it has been clear that changes regarding preparedness and access to PPE needs improvement. Circularity is one way of achieving greater control of the material flow, which affects the hospital's level of independence. The development has proven one way of making the flow of disposable gloves circular by developing an inhouse recycling machine. This thesis work is just one angle of approach towards circularity and more efficient usage of material. To prove the concept in a hospital environment, future development is required. / Bakgrund. Mellan åren 2012 och 2017 har plastförsörjningen i Sverige ökat med nästan 400 000 ton. Under 2017 bidrog sjukhusen i Sverige till 4550 ton plastavfall varav engångshandskar bidrog med 2100 ton, vilket motsvarar 358 miljoner engångshandskar. Majoriteten är tillverkade i andra länder än Sverige, vilket inte bara bidrar till en stor avfallsström, utan också sårbarhet när systemet är beroende av kontinuerlig materialförsörjning. Syfte och Mål. Forskningens syfte har varit att förstå utmaningarna och möjligheterna med plastavfallsflöden från vårdsektorn. Från behoven väljs ett område för att utveckla en innovativ lösning som stöder cirkularitet inom hälso-sjukvården i Sverige. Metod. Denna avhandling har genomförts med hjälp av DRM- och MSPI-innovationsprocess. DRM, Design Research Methodology, har använts för att hitta och validera avgörande information kring problemet och har också gett akademisk trovärdighet. Detta har gjorts med litteraturforskning och ostrukturerade intervjuer inom forskningsområdet. MSPI har använts tillsammans med DRM på iterativt sätt för att utforma det avsedda stödet och bygga det faktiska stödet. Resultat. Projektets prototyp bevisar att cirkularitet för plastmaterial på sjukhus kan nås. Behovsundersökningen visar på behovet av cirkularitet, både när det gäller materiell effektivitet och beredskapsnivåer på sjukhus där tillgången till personlig skyddsutrustning är avgörande. Speciellt i kristider. Slutsatser. Under kristiden, covid-19-pandemin, har det varit tydligt att förändringar avseende beredskap och tillgång till personlig skyddsutrustning måste göras. Cirkularitet är ett sätt att uppnå större kontroll över materialflödet som påverkar sjukhusens självständighetsnivå. Projektet har visat ett sätt att göra flödet av engångshandskar cirkulärt genom att utveckla ett system för remanufacturing. Detta är bara en inställningsvinkel mot cirkularitet och en mer effektiv användning av material. För att bevisa konceptet i en riktig sjukhusmiljö krävs vidareutveckling.
716

Circular Economy in the Biomaterials Sector: Concepts for the Wood Products Industry

Kendria L Huff (10716453) 28 April 2021 (has links)
The concept of the Circular Economy (CE) is proposed as a viable solution to the over-exploitation of natural resources with an economic and environmental backing. Although more commonly used in the context of non-renewable industrial materials and processes, there is a growing need to include these concepts into renewable materials that have technical functions. This thesis will discuss the concepts of CE in the context of the wooden furniture sector and how the inclusion of Value Retention Processes (VRPs) and other CE practices result in quantifiable environmental and economic benefits. Companies that are involved in these VRPs are consulted through a questionnaire. This is to better understand the process and limits of their implementations. The issue of furniture waste is highlighted to demonstrate the need for circularity in this industry and how it fits within the context of CE. A case study is conducted utilizing three comparable furniture products to populate the data needed to utilize an established CE model showcasing their quantifiable benefits (IRP, 2018). This research will lead to a basis for continued research, improvements to current CE models, and suggestions for best practices that can be implemented by industry stakeholders and consumers. The results of the company questionnaire showcase that a viable VRP market exists for the wooden furniture industry, with “Reuse” being the most utilized by consumers. The outputs of the CE model revealed that the inclusion of VRPs results in significant decreases in environmental impacts when compared with new product manufacturing.
717

Making Fashion Consumption Circular : Consumers' Attitudes and Intentions Towards Clothing Rental Subscription

Christmann, Robin, Pasztuhov, Erika January 2021 (has links)
Background:           Today’s fashion industry is one of the most wasteful and polluting industries, which contributes to a global concern. A transition from a linear to a circular approach is needed, in which consumers play a key role. Clothing rental subscription is among the sustainable business models that aim to reduce the production and disposal of clothes by increasing their utilization and extending their lifetime. Based on the attitude-intention relation from the Theory of Planned Behavior and on current literature, we develop a theoretical framework. Purpose:                  The purpose of this study is to investigate the influences of perceived sustainability, perceived enjoyment, perceived financial risk, perceived performance risk, fashion leadership, psychological ownership and perceived convenience on consumers’ attitudes towards clothing rental subscription services and their intentions to engage in this circular fashion business model. Method:                  To fulfill the purpose, we conducted a quantitative study. Primary data was collected through online questionnaires, resulting in 282 responses from German females. Multiple linear regression analyses were conducted to identify the influences of the above-mentioned factors on attitude and on intention. Lastly, a linear regression analysis was used to test attitude’s influence on intention. Conclusion:               The results show that consumers’ attitudes towards clothing rental subscription are positively influenced by the perceived sustainability and perceived enjoyment of the business model, and negatively influenced by perceived financial risk and perceived performance risk. Their intentions to participate in clothing rental subscription were shown to be positively influenced by perceived enjoyment and attitude, while negatively influenced by perceived financial risk. Focusing on one clothing rental business model, we contribute to research in the field and provide valuable implications for practitioners.
718

Long-Lived Particles at the FCC-ee

Sengupta, Rohini January 2021 (has links)
The presented project explores the current theoretical and experimental tools available within the study group for the Future Circular Collider (FCC) with focus on the electron-positron collider. The aim of the study is to evaluate the current frameworks used for simulation, and investigate the possibility of simulating long-lived particles, that could be dark matter candidates, through them. Pythia cards were run through the framework of Delphes and several different software packages were studied on the journey through the work. It was found that the current framework reconstructs the masses of a Z bosons and Higgs bosons accurately from the ZH signal, which is central for the analysis at the FCC-ee. When the same analysis was applied for the new physics case of a dark matter particle included in the new card for study, a ROOT file was produced indicating that the framework was able to handle the new case. When this card was run through the analysis software however, difficulties arose and a final output could not be achieved. Conclusively, it can be said that the current framework has the possibilities of handling new physics cases but further study is required to be able to run certain software packages on these cases.
719

Generating Design Improvements Using Circularity Indicators : A case study on how to measure, increase and evaluate the circularity of a fully automated coffee machine

Svorén, Signe, Gustavsson, Johanna January 2021 (has links)
This thesis presents how circularity indicators successfully can be used to generate concrete design improvements for commercial machines with the aim of making them better adapted to the Circular Economy. By using a methodology based on workshops, assessment of circular maturity from BS8001:2017- Framework for implementing the principles of the circular economy in organizations – guide, and use of the circularity indicator Circularity Measurement Toolkit (CMT) a fully automated coffee machine became 4 percent improved in the circular performance and an 80 percent landfill waste reduction was achieved. As Circular Economy is becoming more accepted as the idea of moving forward towards a more sustainable future, topics on how to measure circularity for organizations and products are increasing. Apart from using circularity indicators together with ecodesign strategies in a case for the first time, this thesis also investigates how a  circular transition of a manufacturing company can be communicated to stakeholders.  With a slight modification of the circularity indicator CMT, the assessment provided a percentage on how circular a fully automated coffee machine is. Identified hotspots in the CMT, matched with areas with improvement potential at the case company, results in three concepts of improvement suggestions. The three concepts are: (1) a modular front to the machine to enable remanufacturing/recycling of the front, presents the option of changing the look of the machine without buying a new one, and lowers the amount of landfill waste, (2) The identity of Luna the barista is integrated into the interface of the coffee machine for emotional durability, and (3) suggestions of how a company can communicate their circular transition through sustainability reports are presented. Both the methodology, the use of circularity indicators to generate design suggestions, and the general idea of concepts are believed to be applicable to any commercial machine in order to improve the circular performance.
720

You Shall Not Pass : A study about Barriers and subsequent Consequences of Sustainable Business Models in the Swedish Clothing & Textile Industry

Munck af Rosenschöld, Carl, Lindholm, Joel January 2021 (has links)
Background: Sustainability is becoming increasingly important from a consumer’s perspective when it comes to their preferences. Simultaneously, mass-market apparel brands are struggling to meet the demand for sustainable clothing and textile products. The industry is in dire need for sustainable development as it is responsible for 8-10% of world’s greenhouse gas emissions and is the cause of 20% of the world’s wastewater. Therefore, it is vital to explore what the barriers are that hinders the development of sustainable business models and the consequences of these barriers.  Purpose: This thesis aims to explore which barriers and subsequent consequences Swedish clothing & textile organizations face when developing a sustainable business model. Method: This study follows the interpretivist approach with inductively inspired reasoning. Qualitative semi-structured interviews are conducted on three different cases, which are analysed and compared using the general analytical procedure. The study used Snoek’s (2017) theoretical framework of internal and external barriers to explore the barriers in the Swedish clothing & textile industry. Findings: This thesis contributes with comprehensive knowledge about barriers and their consequences in the Swedish clothing & textile industry with the help of Snoek’s (2017) framework of internal and external barriers. A total of 24 barriers were classified under four barrier categories; “Costly business model”, “Lack of awareness & low willingness to pay”, “Lack of transparency”, and “Misalignment between policy & regulation within the C&T industry”. Nine were new out of these 24 barriers. A theoretical framework is brought forward illustrating the interconnectivity between “consumer awareness”, “demand and willingness to pay for sustainable products”, “companies match the demand”, and after that “, creating demand for sustainable products”. This study’s findings extend the knowledge about the Swedish clothing & textile industry for organizations that wish to develop sustainability into their business model.

Page generated in 0.2749 seconds