• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 407
  • 159
  • 20
  • 18
  • 18
  • 11
  • 8
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 668
  • 668
  • 260
  • 229
  • 225
  • 170
  • 162
  • 146
  • 143
  • 142
  • 139
  • 133
  • 128
  • 126
  • 101
  • 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.
341

Desarrollo y caracterización de polímeros de alto rendimiento medioambiental derivados de residuos agroindustriales y aditivos de origen renovable

Gómez Caturla, Jaume 31 March 2024 (has links)
Tesis por compendio / [ES] La presente tesis doctoral tiene como principal objetivo el desarrollo de materiales poliméricos que sean respetuosos con el medio ambiente y favorezcan modelos de economía circular, centrando las líneas de investigación en el reaprovechamiento de residuos de la industria del mango y en la utilización de ácido poliláctico (PLA) como principal matriz polimérica. Para ello se emplean diferentes técnicas de procesado como el electrospinning, la extrusión, la inyección o la producción de films por disolución. Además, se plantea la utilización de diferentes aditivos como plastificantes y cargas lignocelulósicas de origen renovable para mejorar las propiedades de estos materiales sin comprometer su alto potencial medioambiental. El primer bloque de la tesis centra sus esfuerzos en el reaprovechamiento de diferentes residuos del mango (uno de los cultivos más populares del mundo), como la piel y el kernel, para desarrollar diferentes materiales con un gran contenido natural. Dentro de los estudios realizados en este bloque se incluye la extracción de almidón a partir del kernel de mango para la posterior fabricación de nanofibras por electrospinning, con gran aplicación en el sector médico. Otros estudios realizados proponen la combinación de matrices poliméricas como el biopolipropileno y el PLA, en combinación con harina de piel de mango y harina de hueso de mango, respectivamente, mediante procesos de extrusión, extrusión reactiva (REX) e inyección. En el caso del biopolipropileno se utilizan además agentes compatibilizantes basados en ácido itacónico para aumentar la adhesión entre las partículas lignocelulósicas de la piel del mango con la matriz polimérica, la cual es altamente apolar. Por otro lado, a las formulaciones de PLA y harina de hueso de mango se le añaden plastificantes como la triacetina y la tributirina para aumentar las propiedades dúctiles del PLA. Un cuarto estudio se enfoca en la producción de films de glicerol con harina de hueso de mango, rica en almidón, para observar cómo afecta el tamaño de partícula de la harina sobre las propiedades de los films. Por último, se propone el desarrollo de materiales termoplásticos ricos en almidón utilizando harina de kernel de mango en combinación con diferentes plastificantes como glicerol, sorbitol y urea. Estos materiales ricos en almidón son procesados por extrusión e inyección y son completamente biodegradables y de origen natural. El segundo y último bloque de la tesis está enfocado a la utilización del ácido poliláctico obtenido de fuentes renovables en procesos de extrusión e inyección. Este poliéster es un polímero biodegradable cuya principal desventaja es su gran fragilidad. Por ello, se han empleado diferentes tipos de plastificantes naturales para incrementar las propiedades dúctiles del PLA. En un primer trabajo, se combina el PLA con α-terpinil acetato, un plastificante de origen renovable. Además, se añade piel de mandarina molida como carga natural para evaluar si este plastificante es capaz de aumentar la ductilidad de mezclas de PLA con cargas lignocelulósicas, obtenido resultados muy positivos. Un segundo trabajo plantea la combinación de PLA con dietil-L-tartrato, un plastificante obtenido del ácido tartárico, encontrado en la uva y el tamarindo, obteniendo elongaciones de más de un 300%. Por último, dos estudios más plantean la combinación de PLA con terpenoides, más concretamente ésteres de geranilo y linalilo. En este sentido, uno de los trabajos se centra en variar la proporción de acetato de linalilo y acetato de geranilo en las composiciones, mientras que el otro trabajo evalúa como afecta la longitud de cadena de los ésteres de geranilo a la plastificación del PLA. Todos los plastificantes utilizados en este bloque ofrecieron resultados muy prometedores, con alargamientos a la rotura superiores al 200% en materiales completamente naturales y biodegradables con gran aplicación en el sector alimentario y del envase y embalaje. / [CA] La present tesi doctoral té com a principal objectiu el desenvolupament de materials polimèrics que siguen respectuosos amb el medi ambient i afavorisquen models d'economia circular, centrant les línies d'investigació en el reaprofitament de residus de la indústria del mango i en la utilització d'àcid polilàctic (PLA) com a principal matriu polimèrica. Per a això s'empren diferents tècniques de processament com l'electrospinning, l'extrusió, la injecció o la producció de films per dissolució. A més, es planteja la utilització de diferents additius com a plastificants i càrregues lignocelulòsiques d'origen renovable per a millorar les propietats d'aquests materials sense comprometre el seu alt potencial mediambiental. El primer bloc de la tesi centra els seus esforços en el reaprofitament de diferents residus del mango (un dels cultius més populars del món), com la pell i el kernel, per a desenvolupar diferents materials amb un gran contingut natural. Dins dels estudis realitzats en aquest bloc s'inclou l'extracció de midó a partir del kernel de mango per a la posterior fabricació de nanofibers per electrospinning, amb gran aplicació en el sector mèdic. Altres estudis realitzats proposen la combinació de matrius polimèriques com el biopolipropilè i el PLA, en combinació amb farina de pell de mango i farina d'os de mango, respectivament, mitjançant processos d'extrusió, extrusió reactiva (REX) i injecció. En el cas del biopolipropilè s'utilitzen a més agents compatibilitzants basats en àcid itacònic per a augmentar l'adhesió entre les partícules lignocelulòsiques de la pell del mango amb la matriu polimèrica, la qual és altament apolar. D'altra banda, a les formulacions de PLA i farina d'os de mango se li afigen plastificants com la triacetina i la tributirina per a augmentar les propietats dúctils del PLA. Un quart estudi s'enfoca en la producció de films de glicerol amb farina d'os de mango, rica en midó, per a observar com afecta la grandària de partícula de la farina sobre les propietats dels films. Finalment, es proposa el desenvolupament de materials termoplàstics rics en midó utilitzant farina de kernel de mango en combinació amb diferents plastificants com glicerol, sorbitol i urea. Aquests materials rics en midó són processats per extrusió i injecció i són completament biodegradables i d'origen natural. El segon i últim bloc de la tesi està enfocat a la utilització de l'àcid polilàctic obtingut de fonts renovables en processos d'extrusió i injecció. Aquest polièster és un polímer biodegradable el principal desavantatge del qual és la seua gran fragilitat. Per això, s'han emprat diferents tipus de plastificants naturals per a incrementar les propietats dúctils del PLA. En un primer treball, es combina el PLA amb α-terpinil acetat, un plastificant d'origen renovable. A més, s'afig pell de mandarina molta com a càrrega natural per a avaluar si aquest plastificant és capaç d'augmentar la ductilitat de mescles de PLA amb càrregues lignocelulòsiques, obtenint resultats molt positius. Un segon treball planteja la combinació de PLA amb dietil-L-tartrat, un plastificant obtingut de l'àcid tartàric, trobat en el raïm i el tamarinde, obtenint elongacions de més d'un 300%. Finalment, dos estudis més plantegen la combinació de PLA amb terpenoids, més concretament èsters de geranil i linalil. En aquest sentit, un dels treballs se centra en variar la proporció d'acetat de linalil i acetat de geranil en les composicions, mentre que l'altre treball avalua com afecta la longitud de cadena dels èsters de geranil a la plastificació del PLA. Tots els plastificants utilitzats en aquest bloc van oferir resultats molt prometedors, amb allargaments al trencament superiors al 200% en materials completament naturals i biodegradables amb gran aplicació en el sector alimentari i de l'envàs i embalatge. / [EN] The present doctoral thesis has as its main objective the development of polymeric materials that are environmentally friendly and promote circular economy models, focusing research on the reuse of waste from the mango industry and the use of polylactic acid (PLA) as the main polymer matrix. Various processing techniques such as electrospinning, extrusion, injection, or cast film are employed for this purpose. In addition, the use of different additives such as plasticizers and lignocellulosic fillers of renewable origin is proposed to improve the properties of these materials without compromising their high environmental potential. The first part of the thesis focuses on the reuse of various mango waste products (one of the most popular crops in the world), such as peel and kernel, to develop different materials with a high natural content. Studies in this section include the extraction of starch from mango kernels for the subsequent production of nanofibers by electrospinning, which have significant applications in the medical sector. Other studies propose the combination of polymeric matrices such as biopolypropylene and PLA, in combination with mango peel flour and mango kernel flour, respectively, through extrusion, reactive extrusion (REX), and injection processes. In the case of biopolypropylene, compatibilizing agents based on itaconic acid are also used to increase the adhesion between lignocellulosic particles from mango peel and the highly apolar polymer matrix. On the other hand, PLA formulations with mango kernel flour are supplemented with plasticizers such as triacetin and tributyrin to enhance the ductile properties of PLA. A fourth study focuses on the production of glycerol films with mango kernel flour, rich in starch, to observe how the particle size of the flour affects the film properties. Finally, the development of starch-rich thermoplastic materials is proposed using mango kernel flour in combination with different plasticizers such as glycerol, sorbitol, and urea. These starch-rich materials are processed by extrusion and injection and are completely biodegradable and of natural origin. The second and final part of the thesis is focused on the use of polylactic acid obtained from renewable sources in extrusion and injection processes. This biodegradable polyester has the main disadvantage of being very brittle. Therefore, different types of natural plasticizers have been used to increase the ductile properties of PLA. In the first study, PLA is combined with α-terpinyl acetate, a renewable plasticizer. In addition, ground tangerine peel is added as a natural filler to evaluate if this plasticizer can increase the ductility of PLA blends with lignocellulosic fillers, yielding very positive results. A second study proposes the combination of PLA with diethyl-L-tartrate, a plasticizer obtained from tartaric acid, found in grapes and tamarind, resulting in elongations of more than 300%. Finally, two more studies propose the combination of PLA with terpenoids, specifically geranyl and linalyl esters. In this regard, one of the works focuses on varying the proportion of linalyl acetate and geranyl acetate in the compositions, while the other study evaluates how the chain length of geranyl esters affects PLA plasticization. All the plasticizers used in this section offered very promising results, with elongations at break exceeding 200% in completely natural and biodegradable materials with significant applications in the food and packaging sectors. / This research is a part of the grant PID2020-116496RB-C22, funded by MCIN/AEI/10.13039/501100011033 and the grant TED2021-131762A-I00, funded by MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR. Authors also thank Generalitat Valenciana-GVA for funding this research through the grant numbers AICO/2021/025 and CIGE/2021/094. Funded with Aid for First Research Projects (PAID-06-22), Vice-rectorate for Research of the Universitat Politècnica de València (UPV). J. I.-M. wants to thank FPU19/01759 grant funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future. J. G.-C. wants to thank FPU20/01732 grant funded by MCIN/AEI/10.13039/ 501100011033 and by ESF Investing in your future. / Gómez Caturla, J. (2024). Desarrollo y caracterización de polímeros de alto rendimiento medioambiental derivados de residuos agroindustriales y aditivos de origen renovable [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203217 / Compendio
342

Svenska klädföretags arbete med cirkulär ekonomi / Swedish fashion brands and their approach towards circular economy

Kellerman, Amanda, Strömstedt, Sandra January 2016 (has links)
I Sverige köps det idag 13,1 kg kläder per person och år, av dessa slängs 8 kg kläder per person och år. Cirka 60 procent av det som slängs skulle dessutom kunna användas igen. Detta är en inte en hållbar resurshantering och för att ta tillvara på kläderna behövs en omställning där kläderna ses som en resurs. Denna studie syftar till att undersöka varför svenska klädföretag arbetar med cirkulär ekonomi, hur de arbetar och vilka svårigheter som kan uppstå med arbetet. Studien genomfördes med hjälp av åtta stycken semistrukturerade intervjuer inom ett brett spektra av svenska klädföretag. De klädföretag som har intervjuats är H&M, Filippa K, Björn Borg, Myrorna, Swedish Stockings, Odd Molly, Fjällräven och Houdini. Erfarenheterna från respondenterna redovisas i fyra olika teman – kläder som resurs, beteendeförändringar, ansvar och överlevnad och förändrad marknadssyn. Det empiriska materialet ställs mot varandra och jämförs med tidigare forskning. Resultatet av studien visar att klädföretagen ser cirkulär ekonomi som deras framtida överlevnad. Det är viktigt att börja se kläderna som en resurs efter användning och det krävs mer arbete i designfasen för att verkligen göra skillnad. Det har även visat sig att det krävs beteendeförändringar för att kunna ställa om till en cirkulär ekonomi. / In Sweden people purchase 13.1 kg garments per person per year, of these garments 8 kg per person per year gets discarded. Approximately 60 percent of the discarded garments could be used again. This is not a sustainable resource management and to take advantage of the garments a transition is needed because the garments have to be seen as a resource. This study aims to investigate why Swedish clothing companies work with circular economy, how they are working with this and what difficulties may arise during the process. The study was conducted with the help of eight semi-structured interviews in a wide range of Swedish fashion companies to share their views and experiences. The clothing companies that have been interviewed are H&M, Filippa K, Björn Borg, Myrorna, Swedish Stockings, Odd Molly, Fjällräven and Houdini. The experience of the respondents are presented in four different themes - clothes as a resource, behavioural changes, responsibility and survival and change in market view. The empirical data are compared against each other and also compared with previous research. The results of the study show that the clothing companies are seeing circular economy as their future survival strategy. It shows that it is important to begin to see the clothes as a resource and further work is required in the design phase in order to really make a difference. It has also been shown that it requires behavioural changes in order to adjust to a circular economy.
343

DESIGN FOR DISASSEMBLY - A CIRCULAR APPROACH

Pervez, Wajiha 01 January 2017 (has links)
As the world becomes increasingly aware of the need to better care for the environment, innovative business models are helping to counter the damage of the fast fashion system - a phenomenon in the fashion industry whereby production processes are expedited in order to get new trends to the market as quickly and cheaply as possible. Designing products with a focus on their renewability can shift the product-consumer relationship. The closed loop concept of a “circular economy” is emerging as a viable and promising solution to the current linear business model. This study explores the possibilities of a more mindful approach to systems of production and consumption through material explorations using plastic from water bottles, paper from old newspaper and magazines, and fabric leftovers from pattern making within a circular economy. It considers the generative and renewable approaches in redefining how fashion engages with the components and raw materials of the industry. The research demonstrates a circular approach to the production of hospitality accessories in an effort to develop new intersections between products, materials, and consumers. The accessories are designed using discarded, reformulated denim–an abundant and underutilized byproduct of the fashion industry­–to reduce waste that currently occurs every time hotel chains and airlines produce disposable giveaway products from new materials.
344

Exploring Prospective Entrepreneurial Engagement and Stakeholders’ Involvement in the Circular Economy : An Empirical Study on the Concept of Växjö Reuse Village

Huang, Bin, Plas, Loukas, Salam, Nader January 2016 (has links)
During the search for a thesis topic, the researchers established contact with a civil servant at Växjö Municipality in Sweden who introduced them to the prospective project of the Reuse Village as part of the city’s waste management plan to enhance circular economy. Hence, the researchers’ purpose for this thesis is to explore the determined values and stakeholders’ involvement linked to the engagement of entrepreneurs towards a circular economy. Moreover, a thorough explanation of the literature review is conducted including the environmental, economic and social sustainability, in addition to the entrepreneurial and stakeholders’ involvement and the different sustainable oriented entrepreneurs and the values that could possibly influence the entrepreneurs. The researchers used mixed research methods that comprise of qualitative interviews, secondary research, and case studies based on documentary secondary data to give a deeper explanation of the stakeholders and entrepreneurial involvement and show their position in the field of circular economy especially in the Reuse Village project. The main findings of the thesis elaborate more on the importance of circular economy that governments and local municipalities are pushing for. The outcome presents the directions that stakeholders lean towards, regarding the Reuse Village, and shows how the relationship between the stakeholders plays a major role in the progress of the notion of circular economy.
345

Logistikbranschens väg till hållbarhet : En studie om logistikbranschens förutsättningar för implementering av cirkulär ekonomi / The logistic sectors’ way to sustainability : A study about the logistic sectors´opportunities for implementation of the circular economy

Behrmann, Linn, Lundqvist, Therese January 2016 (has links)
Bakgrund: Förändringar i konsumtionsmönster har på senare år uppkommit i vårt dagliga liv. Ju mer vi efterfrågar och konsumerar, desto mer ökar transporterna vilket skapar negativa konsekvenser på vår omgivning. Ökat avfall, onödiga kostnader, osunda arbetsförhållanden och ineffektiv användning av tillgångar är exempel på när företag inte tar sitt ansvar på de miljömässiga, ekonomiska samt sociala hållbarhetsområdena. Logistikföretagen har en direkt negativ påverkan på sin omgivning genom dess koldioxidutsläpp från fordonen, och har därmed en direkt möjlighet att kunna påverka detta. Logistikbranschen står idag inför olika utmaningar, men kan genom ett integrerat hållbarhetsarbete erhålla förmåner i både monetära och icke-monetära former. Företagen kan ta ansvar för de miljömässiga, ekonomiska samt sociala aspekterna, vilket benämns som Corporate Social Responsibility (CSR). Den effektiva resurshanteringen som kan implementeras i logistikföretagen utgörs av modellen cirkulär ekonomi och grundas i att reducera, återanvända och återvinna resurser inom verksamheten. CSR och cirkulär ekonomi utgör därmed grunden i denna studie för att ta reda på hur ett hållbarhetsarbete kan tillämpas på bästa möjliga sätt hos företag inom logistikbranschen i Sverige. Syfte: Syftet med denna studie är att undersöka hur logistikföretag i Sverige arbetar med hållbarhet. Vidare avser vi att identifiera och undersöka vilka möjligheter och förutsättningar som finns för implementering av cirkulär ekonomi inom logistikföretag för att skapa ytterligare resurseffektivitet och hållbarhet. Genomförande: Studien har genomförts med en kvalitativ karaktär genom intervjuer med insatta aktörer som har en direkt koppling till logistikbranschen i Sverige. Detta val grundas i att erhålla en ökad förståelse baserad på olika källor från branschen med respondenter som har varierade befattningar och kunskaper. Slutsats: Resultatet av denna studie innebär att en effektiv resurshantering baserad på den cirkulära ekonomins modell kan först uppnås när fyra delar är förverkligade tillsammans med ett hållbart ansvarstagande. Första kravet behandlar en hållbar strategi, det andra kräver att transportbeställaren efterfrågar hållbara transporter. Dessutom krävs även att företagen implementerar hållbara logistikaktiviteter som optimerar verksamhetens resurser. Slutliga kravet begär att intressenter ser incitament till att investera i verksamheten och långsiktiga samt branschöverskridande samarbeten tillsammans med att lagar stiftas för att driva hållbarhetsarbetet framåt. / Background: A shift in consumption has been noted in recent years. The more we demand and consume, the more increases the number of transports which leads to negative consequences in our environment. Logistic firms have a direct effect on the environment through their carbon emissions from their vehicles, therefore they have a direct possibility to influence this. The logistic sector is facing multiple challenges, but can through integrated sustainability actions acquire benefits, in both monetary and non-monetary forms. The companies can be responsible regarding the environmental, economic and social aspects, which is called Corporate Social Responsibility (CSR). The efficient resource management that can be implemented in logistic firms constitutes of the circular economy model, which is based on reducing, reusing and recycling resources within a company. CSR and circular economy compose the base in this study for the investigation of how a logistic firm can in the most optimal approach, implement sustainability actions within the logistic sector in Sweden. Purpose: The purpose of this study is to examine how logistic firms in Sweden work with sustainability. Furthermore, we aim to identify and investigate what are the possibilities and conditions for an implementation of circular economy within logistic firms to create a more resource efficient and sustainable sector. Completion: The study has a qualitative outline through interviews with competent actors that have a direct connection with the logistic sector in Sweden. This decision is based on the aim of obtaining a greater understanding from different sources in the sector with persons that obtain varied positions and knowledge. Conclusion: The results of this study implies that an effective resource management based on the circular economy model only can be achieved when the following four elements are realized with sustainable responsibility. The first requirement deals with a sustainable approach, the second requires that there is a demand for sustainable transports, it also requires that companies implement sustainable logistic activities that optimize business resources. The final requirement is that stakeholders seeks incentives to support and invest in the business both long-term and with cross-sector collaborations together with the laws enacted to drive the sustainability agenda forward.
346

Designing sustainable innovations : Opportunities for new life cycles within the furniture industry

Comacchio, Zeno January 2016 (has links)
The Linear Economy cannot any longer be sustained by the eco-system: virgin resources are limited and destined to terminate soon if the contemporary production and consumption model will be maintained. For this reason, in the last few years Circular Economy has become an increasingly discussed topic worldwide. Through the adoption of strategies that close-the-loop of the traditional linear production system, Circular Economy aims to find solutions that can create a balance between economy, society and environment. This study aims to provide a holistic overview on the main theories and strategies that can ease a business transition to a Circular Economy model, to analyse challenges and opportunities connected to this conversion and to present a concrete tool developed for this purpose. The Life Cycle Design theory is here discussed and contextualised within the furniture industry reality since this study has been executed in collaboration with IKEA, the company case study of this thesis. An academic and professional literature review have been performed in order to gather information about theory and practice related to the implementation of strategies needed by a Circular Economy: product disassembly, recovery, reuse, refurbish, recycle and remanufacturing. The professional literature reviewed point out that the implementation of a circular model can lead to economic advantages and growth’s opportunities for manufacturers in various economic sectors. The implementation of Circular Economy in the furniture industry seems to be in its early stages and it mainly focus, with few exception, on recycling rather than on the more effective reuse, refurbish or remanufacturing operations. This study points out the two main issues that the furniture manufacturers need to solve in order to enable the implementation of more effective circular strategies: product disassembly and recovery. Furthermore, the need of an innovative and holistic approach is discussed with particular emphasis on the importance of a systemic thinking that enable organisation to create their own identity and objectives in relation to the Circular Economy model. The importance of a system that connects and coordinate the sustainable efforts and aims for new products and services is therefore highlighted, suggested and deeply considered in the development of the tool proposed. To conclude, a comparison between two IKEA products (the sofas Söderhamn and Knopparp) was performed to identify the role of the products’ design and development in relation with the implementation of a Circular Economy model. The products were briefly technically analysed and then a comparison between a linear and a circular end-of-life cycle scenario has been represented.
347

Stroller Service System : How to make customer products sustainable within the planetary boundaries - using the case product ‘stroller’, PSS and a Design Thinking approach

Thorslund, Gustav January 2019 (has links)
Physical customer products have an environmental impact, such as greenhouse gas emissions, due to the use of virgin resources from cradle-to-grave, especially when the origin of the material is from fossil resources. This thesis aims to create a circular business model, by investigating the product ‘stroller’ and place it in a Product Service System, where the user subscribes to the Stroller Service System. This means that the product gets a service function: ‘transportation of a child’, mapped with a user-centered approach. The main objective is to lower the ecological footprint by adopting a modular design including bio-based material and stainless steel, and also include services to address economical and social sustainability goals. The methodology that is used is divided into two parts: Status Analysis – which consists of stroller related literature study, literature review and case study, and the second part is the Design Process – creating the product-, service- and system design. The results are grounded in user insights, life cycle assessment and co-creation with experts, where the conclusions are that a PSS Model Stroller should be used by 4-6 users which translate to about 15-20 years of usage for the steel layer. The way of refurbishing the strollers is done by contract workers that exist where the users exists, i.e. Ease Stroller Hub, who change the bio-based material in-between the use-phases and hands over the refurbished stroller to the next user. Add-on services of access to car pools and grocery delivery is included in the system to ease the stroller user’s everyday life and is a way to designing out the need of owning a car, to lower the overall environmental impact.
348

Environmental Performance from Circularity in Products : A Case Study on LED Lighting Fixtures

Longnell, Frida January 2019 (has links)
The circular economy is promoted by the EU, governments, and businesses all over the world as a concept to reach a sustainable future. The concept is embedded into the UN Sustainable Development Goals for 2030 and aims to decouple economic growth and environmental pressure. Many studies have been conducted on the circular economy in recent years but the research on the actual environmental performance of the concept is limited. To move forward with the concept of the circular economy and reach a sustainable future, the environmental performance must be investigated. In this thesis, the environmental impact of circularity in products is investigated by comparing the environmental impact from one circular and one linear product case. To achieve this, the environmental impact and the degree of circularity is calculated with two different methods. The circularity is calculated with a circularity indicator called the Linear Flow Ratio and the environmental impact is assessed with the environmental evaluation technique Life Cycle Assessment (LCA). In the LCAs, the cases are compared for different environmental impact categories (e.g. global warming). The product that is investigated is an LED lighting fixture from the company 2P1. The circular case is based on a leasing business model and includes remanufacturing, reuse and recycling. The linear case includes production, sales, use, and disposal. The LCA results show that the environmental impact from the circular case is lower for all environmental impact categories. The environmental impact is almost exclusively from the manufacturing phase (including extraction and production of raw materials) and the use phase. The circularity results from the Linear Flow Ratio show contradicting results, presenting that the degree of circularity is higher for the linear case. By comparing the results to calculations from another circularity indicator (Material Circularity Indicator), it is concluded that a unified framework for circularity measurements is required. / Cirkulär ekonomi är introducerat av EU, länder och företag över hela världen som ett koncept för att nå en hållbar framtid. Den cirkulära ekonomin är en del av arbetet mot agenda 2030 för hållbar utveckling och strävar efter att frånkoppla ekonomisk tillväxt från miljöpåverkan. Det har forskats mycket på cirkulär ekonomi under de senaste åren men studier som undersöker det miljömässiga utförandet av konceptet saknas. För att fortsätta att utveckla konceptet och för att nå en hållbar framtid så måste den miljömässiga påverkan från cirkularitet undersökas. I denna studie undersöks miljöpåverkan från cirkularitet hos produkter genom att jämföra miljöpåverkan från ett cirkulärt och ett linjärt fall. Miljöpåverkan och cirkularitetsgraden beräknas med två olika metoder. Cirkulariteten beräknas med cirkularitetsindikatorn Linear Flow Ratio och miljöpåverkan analyseras men livscykelanalys. I livscykelanalyserna värderas miljöpåverkan för de två fallen för olika påverkanskategorier (t.ex. global uppvärmning). Produkten som undersökt är en LED-armatur från företaget 2P1. Det cirkulära fallet basers på uthyrning av armaturerna och innehåller renovering, återanvändning och återvinning. Det linjära fallet innehåller produktion, försäljning, användning och bortskaffande av produkten. Resultaten från livscykelanalyserna visar att det cirkulära fallet medför mindre miljöpåverkan för alla kategorier. Miljöpåverkan kommer nästan enbart från produktion (inklusive material) samt användning. Cirkularitetsresultaten från Linear Flow Ratio visar motsägelsefulla resultat då det linjära fallet har en högre cirkularitetsgrad än det cirkulära fallet. Genom att jämföra resultaten med beräkningar från en annan cirkularitetsindikator (Material Circularity Indicator) kan det fastställas att ett enhetligt ramverk för beräkning av cirkularitet är nödvändigt framöver.
349

Potentials, Enablers and Barriers of a Circular Production System in a Lean Manufacturing Context : A Case Study at Scania

Schmitt, Thomas Konstantin, Wolf, Christopher January 2019 (has links)
Exploitative and profit-oriented business operations are unsustainably depleting the world’s resources and extensively harm the environment. Linear production systems within the manufacturing industry are partly held responsible for this ongoing issue as materials and waste are not getting reused but dumped. An alternative to the traditional linear system that increasingly gets attention in the scientific literature is a Circular Production System within the Circular Economy framework, where waste is treated as resources and streamlined back into the production system to create closed resource loops. However, most manufacturing companies nowadays follow linear production systems and have implemented the Lean philosophy to maximize output and profits, leaving environmental aspects rather behind. This context needs to be considered, when thinking of implementing circular measures within a company. Therefore, this study focused on elaborating potentials, enablers and barriers of a Circular Production System in a Lean context. A case study has been conducted within the Swedish commercial vehicle company Scania, located in Södertälje, to gather empirical data about current lean and already ongoing circular practices in a real-life environment, and on future potential of extending circular measures. Internal benchmark studies, including observational studies and semi-structured interviews have been conducted along Scania’s industrial value chain. External benchmark studies contributed to obtain data about already ongoing CPS initiatives within the manufacturing industry. Following the empirical findings, this study suggests that potentials, enablers and barriers are categorized into system, process and product level, which are interdependent and interrelated. The research revealed that due to the many influences from departments along the value chain on the production, the system as a whole needs to be investigated. This study suggests the 4R framework (reduce, reuse, remanufacture, recycle) for implementing a cascaded use of materials. Implementing a new business model giving the product ownership back to companies would facilitate circular flows in the first place. Such a new business strategy can be supported by following more advanced design strategies, that extend the product life and maintain its performance. Lean, however, was found to bear conflict issues, but is considered still useful to some extent to reduce material inputs through more efficient processes.
350

Reviewing environmental rebound effects from peer-to-peer boat sharing in Finland

Warmington-Lundström, Jon January 2019 (has links)
The world crucially needs to reduce the level of emissions being released in the environment in order to combat climate change. With the global population increasing and economies continuing to grow, the circular economy has been heralded by many as the potential solution to economic prosperity whilst also reducing primary resource use and emissions. However, the existence of environmental rebound effect has the potential to severely limit the emission reductions of the circular economy by increasing consumption elsewhere. This paper focuses on the definition of economic rebound effect and on its impact on a peer-to-peer boat sharing platform in Finland. A survey completed by users of the platform allowed for the quantitative analysis of environmental rebound effect experienced by the users and also provide insight into the consumption behaviour that created the most negative consequences. Rebound was experienced by almost all users with almost a third of users experiencing a backfire in which their overall emissions increased as a result of consumption made possible by the economic benefits of shared access. Primary production and the substitution of air travel for the leasing of a boat created large reductions in emissions, however, this was counteracted by increases in personal use and increased air travel by others. This real-life study of environmental rebound effect shows both its existence and impact on the peer-to-peer sharing of boats in Finland.

Page generated in 0.0381 seconds