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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.
1091

Storskalig svensk textilåtervinning : Aktuella problem och rekommendationer för framtiden

Zhang, Rui Liang, Rask, Lukas January 2017 (has links)
Textilindustrin står inför nya utmaningar till följd av den ökande globala textilkonsumtionenoch den ökande avfallsmängden. På grund av bomullens resursintensiva och miljöfarligaproduktion ökar förväntningarna att kunna möta framtidens textilefterfrågan med mindreresursintensiva och mer miljövänliga alternativ. Idag saknar vi en storskalig svensktextilåtervinning och det ökade textilavfallet kan samtidigt hanteras med hjälp av cirkulärekonomi. Genom en uppskalning av en kemisk återvinningsprocess utan stora materialförlusterkan hållbarare alternativ till bomull erhållas samtidigt som textilavfallet hanteras på ett effektivtsätt. Återvinningsprocessen omvandlar bomull till dissolvingmassa (en typ av textilmassa) förviskosproduktion. Därför undersöker vi i detta projekt vilka problem som finns och anger vårarekommendationer för att kunna realisera en sådan textilåtervinning för svenska textilflöden påen större skala, sett ur ett resurseffektivitets- och miljöperspektiv.Vi har genomfört ett kvalitativt projekt med stor vikt på litteratur. Kompletterande intervjuerhar genomförts för att identifiera och kartlägga olika steg i återvinningscykeln. Dessutom hartextilindustrins utveckling analyserats. Utifrån analysen har slutsatser dragits om hur framtidenssituation kan bli för cellulosabaserade textilier. Insamling, sortering, mekanisk och kemiskåtervinning har identifierats som huvudkomponenter och vår slutsats är att dessa behöverutvecklas gemensamt för en fungerande, resurseffektiv och miljövänlig textilåtervinning. Dettagörs för att undvika olika flaskhalsar i återvinningscykeln. Därmed kan en cirkulär ekonomiuppnås. Utifrån analysen konstateras att textilindustrin ändrar karaktär och blir allt merkemibaserad, likt ett bioraffinaderi, där man tar tillvara på alla restprodukter. / The textile industry is facing new challenges as a result of increasing global textile consumptionand the increasing volume of waste. Due to the resource-intensive and environmentallyhazardous production of cotton, expectations are increasing to meet future demand for textileproducts with less resource-intensive and more environmentally friendly alternatives. Todaywe lack a large-scale Swedish textile recycling and the increased amount of textile waste canbe handled by means of circular economy. By scaling up a chemical recycling process withoutmajor material losses more sustainable alternatives to cotton can be obtained while managingthe waste efficiently. The recycling process converts cotton into dissolving pulp (a type oftextile pulp) for viscose production. Thus, we will during this project investigate the problemsthat exist and give our recommendations to implement such a textile recycling for Swedishtextile flows on a larger scale, viewed from a resource efficiency and environmentalperspective.We have made a qualitative study with emphasis on literature studies. Additional interviewshave been conducted to identify and map out various steps in the recycling process. In addition,the development of the textile industry has been analyzed. Based on this analysis, conclusionshave been drawn about how the future situation may be for cellulose-based textiles. Collection,sorting, mechanical and chemical recycling have been identified as main components in therecycling process and our conclusion is that they need to be developed simultaneously for aresource efficient and environmentally friendly textile recycling. The purpose is to avoiddifferent bottlenecks in the recycling process. A circular economy could therefore be achieved.Based on our analysis, a conclusion can be drawn that the textile industry is changing itscharacter and is becoming more chemically intensive, similar to a biorefinery, where allresidues are used.
1092

Wide Viewing Angle Liquid Crystal Displays

Hong, Qi 01 January 2006 (has links)
In this dissertation, novel phase compensation technologies are applied to the designs of wide viewing angle and high transmittance liquid crystal displays. First, a design of wide viewing angle liquid crystal displays utilizing crossed linear polarizers is proposed. The designed multi-domain vertical-alignment liquid crystal display predicts superb contrast ratio over wide viewing angles. Next, to increase the bright state transmittance while maintain the high contrast. Finally, to reduce the cost and improve the applicability of the broadband and wide-view circular polarizer, the device configuration of the broadband and wide-view circular polarizer is significantly simplified by the application of biaxial compensation films. The produced states of polarization remain close to the ideal circular polarization over a wide range of incident angles within the visual spectrum. With this circular polarizer, the presented wide-view liquid crystal display predicts high contrast ratio as well as high and uniform transmittance over wide viewing angles within the visual spectrum. ratio, wide viewing angle circular polarizers are developed. The produced states of polarization are very close to the ideal circular state of polarization over a wide range of incident angles within the visual spectrum. This guarantees not only high contrast ratio but also high and uniform transmittance.
1093

Design Of A Wideband Dual-polarized Cavity Backed Slot Antenna

Paryani, Rajesh 01 January 2010 (has links)
A new technique for designing wideband dual-polarized cavity-backed slot antennas is presented. The structure is in the form of a double-resonant, dual-polarized slot antenna backed by a shallow substrate integrated cavity with a depth of approximately one tenth the free space wavelength. The presence of the cavity behind the slot enhances the antenna's directivity and reduces the possibility of surface wave propagation in the antenna substrate when the element is used in an array environment. Moreover, the dual-polarized nature of this radiating element may be exploited to synthesize any desired polarization (vertical, horizontal, RHCP, or LHCP). The double-resonant behavior observed in this substrate-integrated cavity-backed slot antenna (SICBSA) is utilized to enhance its bandwidth compared to a typical cavity-backed slot antenna. A prototype of the proposed antenna is fabricated and tested. Measurement results indicate that a bandwidth of 19%, an average gain of 5.3 dB, and a wideband differential isolation of 30 dB can be achieved using this technique. The principles of operation along with the measurement results of the fabricated prototype are presented and discussed in this dissertation. The SICBSA is investigated as a candidate for use as an array element. A uniform two element phased array is demonstrated to locate the main beam from boresight to thirty degrees. The potential effects of mutual coupling and surface wave propagation are considered and analyzed.
1094

Greening the thread : A comparative study of design processes to reduce microplastic shedding in Swedish textile companies

Victorsson, Stina, Reynolds, Sonya January 2023 (has links)
Purpose – This study aims to gain an increased understanding of how textile companies perceive opportunities and challenges in reducing microplastic shedding in the design process. Specifically, the thesis compares and analyses two distinct textile companies with diverse business approaches. Methodology – A qualitative research method was chosen to gain in-depth knowledge through semi-structured interviews, while a deductive approach was used to connect existing theories to practical implications. A thematic analysis was employed to systematically analyse the empirical data, aligning with the developed analysis model in the thesis. Findings – Based on the results, it indicates that the design process in the textile industry plays a crucial role in reducing microplastic emissions by enabling sustainable product design through material selection and considering the product's life cycle. However, challenges arise in selecting sustainable materials and implementing sustainable practices due to limited awareness, availability, and standardised measurement methods. Through a comparative analysis of two distinct companies, the study generates valuable insights and knowledge on how organisations can re-evaluate their methods, processes, and material selections to foster more sustainable design practices. Originality/value – This study enhances originality by examining and analysing the perspectives of Swedish textile companies regarding the opportunities and challenges associated with reducing microplastic emissions in the design process. By emphasising a pre-consumer stage in the textile value chain, the study departs from the traditional focus on post-consumer phases, thus addressing the microplastic issue from a new perspective. The findings of this study hold significance for both theoretical and practical realms by advancing an increased understanding of sustainable policies and practices aimed at reducing microplastic emissions in the textile industry.
1095

A skein of Hope: Strategically moving the emerging Swedish wool value chain towards sustainability

Van Acker, Andrea, Nguyen, Trang, Kianian Seyed Abadi, Behnaz January 2023 (has links)
This thesis started with the discovery that in Sweden, about 70% of wool, a valuable material, is wasted in 2017. In recent years, a local value chain in Sweden has gained momentum to increase the use of Swedish wool as a circular and sustainable fibre for the textile industry in the country. This thesis aimed at suggesting a strategic approach to strengthen the Swedish wool value chain. To do so, we used the leverage points framework as a systems thinking lens to uncover system dynamics and assess what is most needed in the system through semi-structured interviews. Then, a systematic literature review was conducted to uncover interventions contributing to sustainable transformations in the global wool value chain and suggest a strategic approach for the Swedish case. The key leverage point that emerged as a result of the research is enhancing the capacity to self-organise as a system, which can happen through increasing collaboration, fostering a structure for learning and flows of information. The strategic intervention that we suggested is to establish a ‘connector’ in the system in order to facilitate underway projects as well as collaboration in a national perspective to develop and expand the use of Swedish wool.
1096

Behaviour of normal and high strength concrete-filled compact steel tube circular stub columns.

El-Lobody, E., Young, B., Lam, Dennis January 2006 (has links)
This paper presents the behaviour and design of axially loaded concrete-filled steel tube circular stub columns. The study was conducted over a wide range of concrete cube strengths ranging from 30 to 110 MPa. The external diameter of the steel tube-to-plate thickness (D/t) ratio ranged from 15 to 80 covering compact steel tube sections. An accurate finite element model was developed to carry out the analysis. Accurate nonlinear material models for confined concrete and steel tubes were used. The column strengths and load¿axial shortening curves were evaluated. The results obtained from the finite element analysis were verified against experimental results. An extensive parametric study was conducted to investigate the effects of different concrete strengths and cross-section geometries on the strength and behaviour of concrete-filled compact steel tube circular stub columns. The column strengths predicted from the finite element analysis were compared with the design strengths calculated using the American, Australian and European specifications. Based on the results of the parametric study, it is found that the design strengths given by the American Specifications and Australian Standards are conservative, while those of the European Code are generally unconservative. Reliability analysis was performed to evaluate the current composite column design rules.
1097

Uncovering the Recycling Distraction: a Graphic Designer’s Journey Designing a Website to Challenge Recycling-Based Individualism

Gruebel, Rhys January 2022 (has links)
No description available.
1098

Hur hållbara är mode-och textilföretagen? : -En jämförelse mellan företag på den svenska och danska marknaden

Bertilsson, Denise, Holm, Karolina January 2023 (has links)
Mode-och textilbranschen är en resursintensiv bransch som står för en stor del av de globala utsläppen. Den har uppmärksammats av EU som en särskilt betydande bransch som måste genomgå förändringar för att bidra till en hållbar utveckling. Stora företag i mode-och textilbranschen i EU behöver de närmaste åren göra en omställning till cirkulära affärsmodeller för att möta kraven som angetts i EU:s cirkulära mål. Trots detta finns det få studier som undersöker hur långt dessa företag kommit i denna omställning. Sverige och Danmark har antagit mer ambitiösa krav på företags hållbarhetsrapportering än EU-direktivet NFRD anger. I denna studie utförs en kvalitativ innehållsanalys av hållbarhetsrapporter från sex mode-och textilföretag på den svenska och danska marknaden. Syftet är att beskriva och analysera hur långt dessa företag kommit i hållbarhetsarbetet och jämföra om det finns skillnader i hur företagen på de olika marknaderna presterar. Resultatet av studiens empiriska analys visar att det finns en homogenitet i hur långt fallföretagen kommit i hållbarhetsarbetet med undantag för ett fallföretag på den danska marknaden. Bortsett från detta undantag har alla företagen satt upp mål för sina koldioxidutsläpp i linje med 1,5-gradersmålet. Cirkulära affärsmodeller pilot-testas i dessa företag. Alla studiens företag placeras i nivån av hållbarhet business-as-usual utifrån den information de presenterat i sina hållbarhetsrapporter. Det kan konstateras att alla företag utom ett uppfyller flera subkriterier både i business sustainability 1, 2 och 3. Fallföretagen och de koncerner-och moderbolag de tillhör har investeringsstilar och ESG-betyg som stärker det empiriska resultat som framkommit. / The fashion and textile industry is a resource-intensive industry that accounts for a large part of global emissions. It has been recognized by the EU as a particularly significant industry that must undergo changes in order to contribute to a sustainable development. In the coming years, large companies in the fashion and textile industry in the EU need to make a transition to circular business models to meet the requirements stated in the EU's circular goals. Despite this, there are few studies that examine how far these companies have come in this transition. Sweden and Denmark have adopted more ambitious requirements for corporate sustainability reporting than the EU directive NFRD specifies. In this study, a qualitative content analysis of sustainability reports from six fashion and textile companies in the Swedish and Danish markets is carried out. The purpose is to describe and analyze how far these companies have come towards becoming sustainable businesses and compare whether there are differences in how the companies in the various markets perform. The result of the study's empirical analysis shows that there is a homogeneity in how far the case companies have come towards becoming sustainable businesses, except for one case company in the Danish market. Apart from this exception, all the companies have set targets for their carbon dioxide emissions in line with the 1.5-degree target. Circular business models are tested in the companies. All the companies in the study are placed in the level of sustainability business-as-usual based on the information they presented in their sustainability reports. It can be stated that all but one company meets several sub-criteria both in business sustainability 1, 2 and 3. The case companies and the groups and parent companies they belong to have investment styles and ESG ratings that strengthen the empirical results that emerged.
1099

Comparative analysis of linear and circular manufacturing system paradigms for a steel-based product. : A case study of a mailbox manufacturing company

ALAGBADA, SAMUEL January 2022 (has links)
The manufacturing industry has exerted a tremendous impact on the natural environment. The aim of this thesis is to evaluate the consequences of shift from linear manufacturing system to circular manufacturing system in order to decouple the environmental burden of production and consumption process in relation to quantity of carbon footprint, cumulative energy demand, natural resource consumption, waste generated and recovered presently. In response to this, life cycle assessment (LCA) is used to quantify and compare the associated environmental impact of the current manufacturing system of both Linear manufacturing system and the circular manufacturing system. The thesis therefore asserts that circular manufacturing system (CMS) is more sustainable compared to linear manufacturing system (LMS) in relation to its reduction capacity of the prevailing environmental indicators most especially global threat of natural resources depletion and climate change confronting biodiversity. The result shown that CMS seems more sustainable compared to LMS in relation to the studied environmental indicators. Further to this, the emerging circular manufacturing system, its transitional shift, challenges, and its relationships with other manufacturing dynamics for consideration are also highlighted and discussed. It was concluded that these prominent challenges are caused by organizational management in relation to leadership and communication (OLC), has the highest impact value. Similarly, the consequential effect was seen on the level of implementation of government policy (GPI) and deployment of state of the art design, knowledge and technology (DTK) for the paradigm shift. So, it is suggested that OLC should be given due consideration.
1100

Design for Recycling : Guidelines for Increased Recycling Efficiency and Recovery Rate of Materials / Design för återvinning : Riktlinjer för ökad återvinnings effektivitet och återvinningsgrad av material

Thureborn, Linn, Yvell, Emma January 2022 (has links)
The manufacturing industry faces a rapidly growing problem which is the increased stream of electronic waste. Due to the fast evolving technology, the innovation cycles have been shortened and the demand for various electronic products has increased. This development requires increasingly advanced material combinations and assemblies to meet both product and customer requirements, which at the same time leads to products becoming more difficult to recycle. Ericsson is one of the world's largest companies in manufacturing and sales of telecom equipment and wants to gain knowledge in how their products are recycled, and how their products should be designed to facilitate the recycling process. As of today, Ericsson has a document from 2004 with design guidelines with a broad focus on the environment. The purpose of this master thesis has been to develop these guidelines, but with a focus on when the product has reached its end of life and is to be recycled. This has been done through an initial collection of secondary data from the literature regarding design for recycling guidelines. These guidelines have been evaluated using a mixed method, where both qualitative and quantitative data have been collected, analyzed and compiled. The biggest focus has been on discussing with recycling experts to get a deeper understanding of what is important for their process to work as efficiently as possible. Finally, a product evaluation has been performed where 3 products have been evaluated against the final set of guidelines to identify areas for improvement. This thesis has provided 30 design guidelines with a focus on increasing the efficiency of the recycling process of Ericsson's products. These guidelines cover 3 different areas: Material and material combinations, Fasteners and connectors, and Labels and markings. It is recommended that these guidelines should be implemented as early as possible in Ericsson's product development process to have the greatest impact on the final design of new products. / Tillverkningsindustrin står idag framför ett snabbt växande problem, nämligen den ökande mängden av elektroniskt avfall. På grund av den snabbt utvecklande teknologin så har innovations cyklerna förkortats och efterfrågan på olika elektroniska produkter ökat. Denna utveckling kräver allt mer avancerade materialkombinationer och sammansättningar för att möta både produkt- och kundkrav, vilket samtidigt leder till att produkter blir allt svårare att återvinna. Ericsson är ett av världens största företag inom tillverkning och försäljning utav telecom utrustning och vill i större utsträckning kartlägga hur deras produkter återvinns, samt hur deras produkter bör designas för att underlätta återvinningsprocessen. I dagsläget har Ericsson ett dokument från 2004 med design riktlinjer med ett brett fokus på miljö. Syftet med detta examensarbete har varit att utveckla dessa riktlinjer, fast med ett fokus på när produkten nått slutet på sin livslängd och ska återvinnas. Detta har genomförts genom en initial insamling av data genom en litteraturstudie gällande designriktlinjer för återvinning. Dessa riktlinjer har utvärderats med en empirisk studie, där både kvalitativ och kvantitativ data har insamlats, analyserats och sammanställts. Störst fokus har legat på att diskutera med experter inom återvinning för att få en bra förståelse vad som är viktigt för att deras process ska fungera så effektivt som möjligt. Slutligen genomfördes ett test där tre produkter utvärderades med de slutliga riktlinjerna för att identifiera förbättringsområden. Detta examensarbete har resulterat i 30 design riktlinjer med fokus på att öka effektiviteten av återvinningsprocessen av Ericssons produkter. Dessa riktlinjer berör tre olika områden: Material och material kombinationer, Fästelement och kopplingar samt Etiketter och markeringar. Det rekommenderas att dessa riktlinjer implementeras så tidigt som möjligt i Ericssons produktutvecklingsprocess för att få störst inverkan på den slutliga designen för nya produkter.

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