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  • 1.
    Aamir Latif, Muhammad
    University of Borås, School of Engineering.
    Radar scattering from bodies of revolution using an efficient partial differential equation algorithm2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    A technique is presented for solving the problem of scattering by a three-dimensional body of revolution using a partial differential equation (PDE) technique, employed in conjunction with radiation boundary condition applied in the Fresnel region of the scatterer. The radiation boundary condition, which is used to truncate the PDE mesh, is based upon an asymptotic expansion derived by Wilcox. Numerical results illustrating the procedure and verifying the accuracy of the results are included. These results are compared with other theoretical calculations for perfectly conducting bodies of revolution of arbitrary shape.

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    FULLTEXT01
  • 2.
    Abbasi, Maisam
    University of Borås, School of Engineering.
    Perspectives of Complexity and Intelligence on Logistics and Supply Chain Management2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    In recent decades, millions of articles, books and journals have been written and thousands seminars and conferences have been held to present increasing importance of supply chain management both in practice and theory. Undoubtedly, nowadays, success is not tied-up just in processes of a focal company but in processes of all its value chain and network. In order to survive in highly competitive markets, it sounds essential that all processes and entities of the supply and demand network be analyzed and value-adding ones be separated from those which are not. One of the origins of non-value adding processes is non-value adding complexity. So, a systematic study and analysis of supply chain complexity and rendering remedies for simplicity are essential. In this thesis, at first, some definitions as well as causes of supply chain complexity based on its complication and complexity are mentioned. In the next step, embodiments of some themes of complexity science in discipline of supply chains are explained. Later, a recipe for studying complexity is offered. Ingredients of this recipe are identification, classification, measurement, modeling, and simplification. Finally, implementation of intelligent agents as assured tools for simplification of supply chains complexity is described.

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    FULLTEXT01
  • 3.
    Abbasi, Maisam
    et al.
    Lund University.
    Nilsson, Fredrik
    Lund University.
    Waidringer, Jonas
    Chalmers.
    Outlook of Complexity and Complication on Logistics and Supply Chain Management2009In: NOFOMA 2009, Jönköping Sweden: Nofoma , 2009Conference paper (Refereed)
  • 4.
    Abbasi, Ziwar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bernebrand, Anna
    University of Borås, Faculty of Textiles, Engineering and Business.
    Projektering av elnätet för ett exploateringsområde2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The growing population in Sweden has led to the great need for new housing construction in the last decade. Consequently, new housing construction has increased substantially. To meet the capacity requirement, large investments are required from the electricity grid companies to connect the newly built residential areas and to enable the development of new infrastructure. The expansion opportunities that have arisen in the current municipality have led to the expansion of the grid for a new residential area. The purpose of the project is to find a rational solution to provide an exploitation area of 19 homes with electricity. To achieve a desirable result with the distribution planning, corporate guidelines and industry standards have been used. The projected distribution network is designed by a radial system, which means that power supply takes place only from one direction. The distribution network is made up of two different distribution systems: TN-S and TN-C. The distribution planning also includes network calculations carried out with both optimization software NetBas and manually. The parameters that have been calculated are voltage drops, short-circuit currents and short-circuiting time. The dimension of the distribution network, is calculated only through NetBas, it resulted in the installation of a network station, five cable cabinet, 0.9 kilometers low voltage cable and 0.13 kilometers high voltage cable. The project's total investment cost has approximately been estimated at 568 000 Swedish crowns.

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    fulltext
  • 5. Abbaszadeh, A
    et al.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Effect of extraction conditions on yield and purity of citrus pectin by sulfuric and hydrochloric acids2009Conference paper (Refereed)
  • 6.
    Abburi, Sridhar
    et al.
    University of Borås, School of Business and IT.
    Chinnappan, Ramakrishnan
    University of Borås, School of Business and IT.
    COLLABORATION IN BANKING INFORMATION SYSTEMS: INVESTIGATING THE FUTURE OF BANKING SYSTEMS IN INDIA2013Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Banking systems in India is quite popular and it needs some more changes to reach all the customers. Lack of the service is main problem in Indian baking system. If the common person wants to open the account, it take’s little bit high cost and banks are not near the people location. Due to the Lack of service, people do not want to be a customer of the bank. In the research trying to find the solutions for some of the problems to maintain a banking account, we want to provide the maximum time of service in banking systems and to find the better solution for the common persons to use the banking systems. The research idea Collaboration banking information systems are designed to combine all the account information into a system, to provide a better solution for the customer, and to solve all the internal problems in the banking systems. From this new concept we could establish the bank in each and every village, So that we could reach all the customers by providing them a good quality service and exceeding their expectations. The Collaboration systems are less time consuming and it reduces the burden of both the customers and bank employees. Some banks failed due to the lack of customers and the over burden of interest charged by the government. The research idea is to share all the account details from all the banks into a system that is known as collaboration banking information systems. The collaboration banking systems are entirely different and it reduces the cost maintenance of the Indian banking systems.

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  • 7.
    Abd Al Sater, Wissam
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effektiv logistik med lossningskalender på byggarbetsplatsen2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Logistics has long been a topic for discussion that has recently gained more attention. In order for the supervisor to develop a logistics organization that works more than well, this always means that the internal logistics routines are well functioning. The procedures should work on guidelines and support for the supervisor in all types of projects. The study aims to study NCC-projects that use and / or do not use the new tool, release calendar, to identify its positive results. The study uses a qualitative method in which the author conducts interviews with 4 respondents within NCC. The result consists of three main categories processing collected data, these categories are: Efficiency, documentation and Support for work management. Electronic logistics tools like the unloading calendar are of great importance to the supervisor and can be decisive in the quality of all construction projects.

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    fulltext
  • 8.
    Abdi Adille, Samira
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Johannesson, Anna
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sifariny, Maha
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zejnilovic, Mirela
    University of Borås, Faculty of Textiles, Engineering and Business.
    Samspel mellan hållbarhet och lönsamhet i ett transportföretag2020Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    The purpose of the study was to develop sustainability factors and investigate how transport companies can achieve a good interaction between sustainable development and profitability. Based on this purpose, improvement proposals and achievable solutions were developed with consideration to requirements from customers, authorities and the EU.

    The used method was qualitative in which respondents from the company and authorities participated in semi-structured interviews. In addition, a literature study was also conducted to map information from more perspectives than just the respondents. During the course of the study, other methods were also used where they were suitable to strengthen the results.

    The results presented several sustainability factors in a transport company that must be taken into account, where, among other things, the choice of fuel, demands from politicians and customers were different factors. To report the results, different types of analysis were done, such as SWOT and ABC analysis.

    Finally, based on the method, the information gathered and an analysis and discussion, the sustainability factors were developed. They were analyzed and examined for future improvements. The study of the company has shown that a combination of better sustainability and a positive financial advantage can be found and balanced. A company can invest in becoming more sustainable and more profitable.

  • 9.
    Abdulhadi, Jessica
    et al.
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare.
    Haradinaj, Vjollca
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare.
    Kvinnors och mäns arbetsmiljö: En kvantitativ jämförande studie om hur kvinnor och män upplever den psykosociala arbetsmiljön2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of our study is to investigate men's and women's experiences of their psychosocial work environment. To fulfil our purpose and our questions the following research question were formulated “Is there any difference between men and women's experience of stress, bullying, sexual harassment, social support, management support and autonomy in their work environment?” The study has been conducted via our web survey on social media, Facebook and LinkedIn. Our method has been of a quantitative nature and implemented with 112 respondents. To get as many answers as possible, we have shared the questionnaire publicly and via messenger with friends who could take part of it. The reason why this material is used in this study is that it can contribute to an understanding of the respondents' experience of stress, bullying, social support, manager support, sexual harassment, autonomy, influence and self-control, and to be able to compare differences between men and women in these aspects. The result showed that in some cases there are differences between men and women. However, the result showed that there were no significant gender differences. This suggests that further research should continue to investigate gender differences regarding stress, bullying, sexual harassment, social support, managerial support, autonomy, influence and self-control, since the result can be interpreted as being that generalizing conclusions in this regard cannot be drawn at this time.

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    A-K2019:4
  • 10.
    Abdullah, Didan
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bajramovic, Dino
    University of Borås, Faculty of Textiles, Engineering and Business.
    Konvertering av lokaler till studentbostäder: Ett komplement för att lösa studentbostadskrisen?2019Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Demand for housing has been at a high level in Gothenburg for a long time now. The population of Gothenburg is growing as it reached one million inhabitants about two years ago. There will also be more and more students in the city, the lack of student housing is very extensive in Gothenburg. The situation seems to be improving, but in the long term, there are currently 9,000 student residences in Gothenburg, but more than 12,000 students only attend the University of Gothenburg. The Gothenburg housing student foundation states that more than 7,000 student housing must be built until 2026 to cover the need. At the same time, the queue time is more than one and a half years for a student residence. The new production of student housing has not increased significantly during the last few years, despite the fact that ordinary housing is being built, but not for students. Continuing this, more students will choose to study in another place where they get housing immediately. There, conversion of old premises to student housing comes in. This could have been a good alternative, but it has not been researched enough if it can be a good complement. This bachelor thesis aims to review whether one can find a good complement to the lack of student housing crisis in Gothenburg. A number of factors have been developed that prevent conversions today. The planning process system is one of the major problems that hinders conversions of premises to student housing. Lead times are also a big problem for implementing conversions, had more officials been available so it would be faster to get through plans. The building rules are also a major problem that prevents conversions. Similar building rules apply to a new production as for a conversion of a building. Regulations and laws must be adapted more to a building of student housing. Costs that are unforeseen will always be a big problem, builders who have carefully examined an object to be converted and have experience run less risk of unforeseen costs. Different contribution schemes as a subsidy system prevent a natural development of the market and are not a good alternative.

  • 11.
    Abdullah, Sara
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Al Qarghulli, Ahmed
    University of Borås, Faculty of Textiles, Engineering and Business.
    Majzoub, Nour Eddin
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kommunikation på en byggarbetsplats2022Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There is a great need for a well-functioning communication in the construction industry, with the reason that it is an extensive industry where many different professional roles are involved. Communication can be lacking in many areas and can turn into negative effects on a project. In the construction industry, unpredictable changes often occur, which can make effective communication more difficult to achieve.

    This study is about understanding how communication can be challenging and affect construction projects during production. The purpose of this study is to find measures to prevent lack of communication and carefully study whether it can increase involvement, community, and motivation on a construction site, by examining and analyzing how information is disseminated among involved parties in a project under production.

    The study answers the following questions:

    • How do you communicate on a construction site?
    • Does communication increase involvement, community, and motivation on a construction site?
    • Can you save money by increasing communication skills at the construction site?

    Qualitative interviews were conducted on some employees at GH Olofsson Bygg & Entreprenad AB to create an idea of how communication works and is experienced in their workplace.

    The result of the interviews showed that communication was in some cases less good and that misunderstandings arose many times. The study delves into how communication is experienced and processed and how to make it more efficient. It also delves into which communication methods are used and which are most suitable in different situations. The results indicate that the most appreciated way to communicate is face-to-face meetings. However, it turned out that this method of communication is not always appropriate as factors such as time pressure or sudden changes may occur.

    One measure that is discussed in the study is, among other things, that all employees at the company must complete a course that deals with the value of communication and how it can be applied in a way to reduce misunderstandings. By implementing that measure, communication deficiencies can be prevented from the beginning. As a result of this measure, money can be saved in the long run even though it can be costly in the beginning.

  • 12.
    Abdusemed, Wefae
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Shahin, Antonella
    University of Borås, Faculty of Textiles, Engineering and Business.
    Gustafsson, Maria
    University of Borås, Faculty of Textiles, Engineering and Business.
    Anställningsbarhet: hur har nyexaminerade studenter formats inför framtida arbetsliv2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Employability among newly graduated students, a concept that is being discussed more as of late, as well as it is growing. The interesting aspect of the concept is how you, as an individual, can contribute in order to better your employability skill or competence. Additional interesting aspects subsists of which factors within employability that are interesting among the employers and what the government, different organizations or education can do to contribute for a greater employability skill set. However, this thesis mainly focuses on what it actually means to be employable. This study is based on an analysis between two groups, one study group and one control group. The study concludes whether newly graduated students from two different groups feel that it is somewhat difficult to enter the labor market, where the study group have had some kind of connection with different business companies, through experience or shorter internships. How well do the individuals within these two different groups know their own employability? The aim of the study is to analyze whether there is a difference between the newly graduated students, within the two different groups, regarding their employability. Moreover, whether the students from the study group with internship experiences within their degree, have better employability competence or not. In order to reach out to a larger group, which we decided to define to no later graduation than five years prior to this study, we decided to use a quantitative method. A questionnaire survey was conducted where the survey was based on fixed options with possibility for voluntary supplementary comments. Furthermore, the choice of a questionnaire fell naturally because of the time limit as well as the need of a large amount of answers to reach the purpose of the study. A total of 183 answers were obtained where 1213 questionnaire were sent out, giving a response rate of 15, 09 percent and a loss of 84, 9 percent in the study. Based on the respondents results on their estimation of their different characteristics, which were in connection with the different employability factors, has the following concluding results been drawn: When it comes to the respondents’ estimation of themselves in the survey, the three most common options, which they consider to have acquired their characteristics from, are: education, family / upbringing and previous employment. The research group and the control group showed similar values and results, with no major differences. However, some interesting relations were found.

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  • 13.
    Abed, Samah
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Al-Kaisee, Farah
    University of Borås, Faculty of Textiles, Engineering and Business.
    Metallutvinning med fokus på zinkfrån avfallsflygaska med hjälp avsura processvatten2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden produces large amount of fly ash from waste combustion annually. Combustion the

    waste generates two types of ashes, bottom ash/slag, and fly ash. Bottom ash is considered to

    be more environmentally friendly and has a wide area of application such as road

    constructions on landfills. While the fly ash has high level of heavy metals and for instance

    dioxines which are harmful for the environment. This type of ash are deposited in a landfill

    and gets classified as a hazardous waste which is expensive given that the deposit fee is high.

    The fact that fly ash contains valuable metals as zinc, methods of recovering it are being

    developed such as acid leaching. This is a promising method as the leachate used are acid

    process water making the usage of the chemicals substantially lower which makes it

    financially viable.

    Waste incinerators in Sweden produce approximately 200 000 tons of fly ash annually and the

    majority of it is transfered to Norway to get treated and put on a landfill. Some waste

    management companies, e.g. Renova, are using another method called “the Bamberg method”

    where fly ash is mixed with sludge to form a cake and put in the company’s own landfill.

    The projects goal is to leach the fly ash by using acidic process water to obtain the metallic

    substance particularly zinc making it easier and cheaper to landfill the ash and also to

    optimize this method to get the most zinc out of the ash using minimum amount of the acidic

    process water (5% HCI).

    The laboratory work took place in the University of Borås. Fly ash and the acid process water

    which were used under the laboratory work was obtained from RenovaAB.

    The results shows that leaching the fly ash with acidic process water gave different release of

    zinc but was 88% at most. The variation in the results depends on a few factors such as

    amount of acidic process water, pH, time, blending time and the ashes content.

    This project took environment and access to acidic water in consideration, which optimized

    the method of using less amount of acid process water to get the most zinc as possible.

    The results shows that leaching fly ash with acid process water is cost efficient and easy way

    to recover zinc, which satisfy the goals of the project.

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  • 14.
    Abedinifar, S.
    et al.
    Department of Chemical Engineering, Isfahan University of Technology.
    Karimi, K
    Department of Chemical Engineering, Isfahan University of Technology.
    Khanahmadi, M.
    Isfahan Agriculture and Natural Resources Research Centre.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ethanol production by Mucor indicus and Rhizopus oryzae from rice straw by separate hydrolysis and fermentation2009In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 33, no 5, p. 828-833Article in journal (Refereed)
    Abstract [en]

    Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and β-glucosidase enzymes were first investigated and their best performance obtained at 45 °C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g-1 sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g-1) and untreated straw (0.46 g g-1). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L-1 resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g-1 ethanol, 0.11-0.17 g g-1 biomass, and 0.04-0.06 g g-1 glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g-1 ethanol, 0.04-0.10 g g-1 biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g-1. This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g-1, respectively. 

  • 15. Abedinifar, Sorahi
    et al.
    Karimi, Keikhosro
    University of Borås, School of Engineering.
    Khanahmadi, Morteza
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Ethanol production by Mucor indicus and Rhizapus oryzae from rice straw by separate hydrolysis and fermentation2009In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 33, no 5, p. 828-833Article in journal (Refereed)
    Abstract [en]

    Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and beta-glucosidase enzymes were first investigated and their best performance obtained at 45 degrees C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g (1) sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g (1)) and untreated straw (0.46 g g(-1)). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L-1 resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g(-1) ethanol, 0.11-0.17 g g(-1) biomass, and 0.04-0.06 g g(-1) glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g(-1) ethanol, 0.04-0.10 g g(-1) biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g(-1). This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g(-1), respectively. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

  • 16.
    Abrahamsson, Daniel
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Petersson, Oscar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Anbud: Faktorer och förbättringsmöjligheter i anbudsprocessen2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The report shows how extensive the tender process is and what factors to consider in order tosubmit a winning bid. It highlights the different parts of the tender process and makes adeeper analysis of some of the most important factors. Bidding is not just about value whatsomething will cost. Because companies rarely are alone, they are finding ways and solutionsthat make the offer competitive. There is a high pace in the construction industry andconstruction companies currently have a lot to do.The report is written together with RO-Gruppen and a survey is the basis for the analysis. Thegoal was to describe RO-Gruppens work and to find possible improvement potential.As specifications, customers and procurement variations vary, it’s difficult to always followthe same template. Transparency and flexibility is required to analyze what exactly the clientis looking for. Experience proved to be a decisive factor, both according to the literature andthe questionnaire survey.

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    Anbud
  • 17.
    Abrahamsson, Pontus
    et al.
    University of Borås, School of Engineering.
    Svedberg, Pierre
    University of Borås, School of Engineering.
    Sanering av kontaminerad mark2008Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    På uppdrag av Nexans IKO Sweden AB har MK Bygg AB genomfört saneringsarbete av kontaminerad mark i Tranemo kommun. 1947 ändrade Nexans IKO Sweden AB verksamhet från att har brutit torv till att tillverka kablar. Denna verksamhet genererade en del spillkabel och i denna fanns den värdefulla metallen koppar. På Nexans IKO Swedens område brändes spillkablar för att komma åt kopparen. Detta skedde mellan åren 1947 och 1967. Då kabeln innehöll PVC bildades vid förbränningen dioxiner och furaner. P.g.a. denna hantering behövde området saneras. MK Bygg AB:s uppdrag har huvudsakligen bestått av att schakta bort jordmassor från det kontaminerade området. De massor som har varit mindre kontaminerade har fraktats till Nexans angränsande egendeponi. Syftet med denna rapport har varit att hjälpa MK Bygg AB med delar av kontrollen och utvärderingen av saneringsarbetet. Underlag har tagits fram för godkännande av länsstyrelsen. Detta underlag har sedan använts för att upprätta egenkontrollplanen. Egenkontrollen omfattar huvudsakligen kontroller av schaktning, jord och spridningsförhindring. Den viktigaste delen av egenkontrollen har varit har förhindra spridning av kontaminerat material vid saneringsarbetet. Utifrån de undersökningar och bestämmelser som var framtagna av Envipro Miljöteknik och DGE mark och miljö AB har saneringsarbetet utförts på ett noggrant sätt. Eftersom ett flertal industrier tidigare inte har tagit hand om avfall på ett lämpligt sätt så kommer saneringsarbeten att behöva utföras under de närmaste åren. Vi tror att det i framtiden kommer att ställas hårdare krav på sanering av kontaminerade områden. Detta är något som vi anser kommer att bidra till större möjligheter att utnyttja markområden och framförallt till en bättre miljö.

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    FULLTEXT01
  • 18. Abtahi, F.
    et al.
    Gyllesten, I. C.
    Lindecrantz, Kaj
    University of Borås, School of Engineering.
    Seoane, Fernando
    University of Borås, School of Engineering.
    Software Tool for Analysis of Breathing Related Errors in Transthoracic Electrical Bioimpedance Spectroscopy Measurements2012Conference paper (Refereed)
  • 19. Abtahi, F
    et al.
    Seoane, F
    University of Borås, School of Engineering.
    Lindecrantz, K
    University of Borås, School of Engineering.
    Electrical bioimpedance spectroscopy in time-variant systems: Is undersampling always a problem?2014In: Journal of Electrical Bioimpedance, E-ISSN 1891-5469, Vol. 5, no 1, p. 28-33Article in journal (Refereed)
    Abstract [en]

    During the last decades, Electrical Bioimpedance Spectroscopy (EBIS) has been applied mainly by using the frequency-sweep technique, across a range of many different applications. Traditionally, the tissue under study is considered to be time-invariant and dynamic changes of tissue activity are ignored by treating the changes as a noise source. A new trend in EBIS is simultaneous electrical stimulation with several frequencies, through the application of a multi-sine, rectangular or other waveform. This method can provide measurements fast enough to sample dynamic changes of different tissues, such as cardiac muscle. This high sampling rate comes at a price of reduction in SNR and the increase in complexity of devices. Although the frequency-sweep technique is often inadequate for monitoring the dynamic changes in a variant system, it can be used successfully in applications focused on the time-invariant or slowly-variant part of a system. However, in order to successfully use frequency-sweep EBIS for monitoring time-variant systems, it is paramount to consider the effects of aliasing and especially the folding of higher frequencies, on the desired frequency e.g. DC level. This paper discusses sub-Nyquist sampling of thoracic EBIS measurements and its application in the case of monitoring pulmonary oedema. It is concluded that by considering aliasing, and with proper implementation of smoothing filters, as well as by using random sampling, frequency-sweep EBIS can be used for assessing time-invariant or slowly-variant properties of time-variant biological systems, even in the presence of aliasing. In general, undersampling is not always a problem, but does always require proper consideration.

  • 20.
    Abtahi, Farhad
    et al.
    Karolinska Institutet.
    Anund, Anna
    Fors, Carina
    Seoane, Fernando
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås, Faculty of Caring Science, Work Life and Social Welfare. Karolinska Institutet.
    Lindecrantz, Kaj
    University of Borås, Faculty of Textiles, Engineering and Business. Karolinska Institutet.
    Association of Drivers’ sleepiness with heart rate variability. A Pilot Study with Drivers on Real Road2017Conference paper (Other academic)
  • 21. Abtahi, Farhad
    et al.
    Aslamy, Benjamin
    Boujabir, I
    Seoane, Fernando
    University of Borås, School of Health Science.
    Lindecrantz, Kaj
    University of Borås, School of Engineering.
    An Affordable ECG and Respiration Monitoring System Based on Raspberry PI and ADAS1000: First Step towards Homecare Applications2014In: 16th Nordic-Baltic Conference on Biomedical Engineering / [ed] Mindedal H., Persson M., Springer International Publishing , 2014, p. 5-8Conference paper (Refereed)
    Abstract [en]

    Homecare is a potential solution for problems associated with an aging population. This may involve several physiological measurements, and hence a flexible but affordable measurement device is needed. In this work, we have designed an ADAS1000-based four-lead electrocardiogram (ECG) and respiration monitoring system. It has been implemented using Raspberry PI as a platform for homecare applications. ADuM chips based on iCoupler technology have been used to achieve electrical isolation as required by IEC 60601 and IEC 60950 for patient safety. The result proved the potential of Raspberry PI for the design of a compact, affordable, and medically safe measurement device. Further work involves developing a more flexible software for collecting measurements from different devices (measuring, e.g., blood pressure, weight, impedance spectroscopy, blood glucose) through Bluetooth or user input and integrating them into a cloud-based homecare system.

  • 22.
    Abtahi, Farhad
    et al.
    University of Borås, School of Health Science.
    Berndtsson, A
    University of Borås, School of Health Science.
    Abtahi, Shirin
    University of Borås, School of Health Science.
    Seoane, Fernando
    University of Borås, School of Health Science.
    Lindecrantz, Kaj
    KTH.
    Development and preliminary evaluation of an Android based heart rate variability biofeedback system2014Conference paper (Refereed)
    Abstract [en]

    The reduced Heart Rate Variability (HRV) is believed to be associated with several diseases such as congestive heart failure, diabetes and chronic kidney diseases (CKD). In these cases, HRV biofeedback may be a potential intervention method to increase HRV which in turn is beneficial to these patients. In this work, a real-time Android biofeedback application based on a Bluetooth enabled ECG and thoracic electrical bioimpedance (respiration) measurement device has been developed. The system performance and usability have been evaluated in a brief study with eight healthy volunteers. The result demonstrates real-time performance of system and positive effects of biofeedback training session by increased HRV and reduced heart rate. Further development of the application and training protocol is ongoing to investigate duration of training session to find an optimum length and interval of biofeedback sessions to use in potential interventions.

  • 23.
    Abtahi, Farhad
    et al.
    KTH-School of Technology and Health.
    Ji, Guangchao
    KTH-School of Technology and Health.
    Lu, Ke
    KTH-School of Technology and Health.
    Rödby, Kristian
    University of Borås, Faculty of Textiles, Engineering and Business.
    Björlin, Anders
    Kiwok AB.
    Östlund, Anders
    Kiwok AB.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Lindecrantz, Kaj
    KTH-School of Technology and Health.
    Textile-Electronic Integration in Wearable Measurement Garments for Pervasive Healthcare Monitoring2015Conference paper (Other academic)
  • 24.
    Abtahi, Farhad
    et al.
    KTH-School of Technology and Health.
    Ji, Guangchao
    KTH-School of Technology and Health.
    Lu, Ke
    KTH-School of Technology and Health.
    Rödby, Kristian
    University of Borås, Faculty of Textiles, Engineering and Business.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    A knitted garment using intarsia technique for Heart Rate Variability biofeedback: Evaluation of initial prototype2015In: Proceedings of the 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015, p. 3121-3124Conference paper (Refereed)
  • 25.
    Abtahi, Farhad
    et al.
    Institute of Environmental Medicine, Karolinska Institutet, 171 65 Stockholm, Sweden; School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden.
    Lu, Ke
    School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden.
    Diaz-Olivares, Jose A
    School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden.
    Forsman, Mikael
    Institute of Environmental Medicine, Karolinska Institutet, 171 65 Stockholm, Sweden.
    Seoane, Fernando
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås, Faculty of Caring Science, Work Life and Social Welfare. Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Hälsovägen 7, 141 57 Stockholm, Sweden; Department of Biomedical Engineering, Karolinska University Hospital, 171 76 Solna, Sweden .
    Lindecrantz, Kaj
    University of Borås, Science Park Borås. Institute of Environmental Medicine, Karolinska Institutet, 171 65 Stockholm, Sweden .
    Wearable Sensors Enabling Personalized Occupational Healthcare2018In: Intelligent Environments 2018 / [ed] Ioannis Chatzigiannakis, Yoshito Tobe, Paulo Novais, Oliver Amft, Amsterdam: IOS Press, 2018, p. 371-376Chapter in book (Other academic)
    Abstract [en]

    This paper presents needs and potentials for wearable sensors inoccupational healthcare. In addition, it presents ongoing European and Swedishprojects for developing personalized, and pervasive wearable systems for assessingrisks of developing musculoskeletal disorders and cardiovascular diseases at work.Occupational healthcare should benefit in preventing diseases and disorders byproviding the right feedback at the right time to the right person. Collected datafrom workers can provide evidence supporting the ergonomic and industrial tasksof redesigning the working environment to reduce the risks.

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    fulltext
  • 26.
    Abtahi, Farhad
    et al.
    KTH-School of Technology and Health.
    Lu, Ke
    KTH-School of Technology and Health.
    Dizon, M
    KTH-School of Technology and Health.
    Johansson, M
    KTH-School of Technology and Health.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Lindecrantz, Kaj
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Evaluating Atrial Fibrillation Detection Algorithm based on Heart Rate Variability analysis2015In: Medicinteknikdagarna, Uppsala: Svensk förening för medicinsk teknik och fysik , 2015Conference paper (Refereed)
  • 27.
    Abtahi, Farhad
    et al.
    KTH-School of Technology and Health.
    Lu, Ke
    KTH-School of Technology and Health.
    Dizon, M
    KTH-School of Technology and Health.
    Johansson, M
    KTH-School of Technology and Health.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Lindecrantz, Kaj
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Evaluation of Atrial Fibrillation Detection by using Heart Rate Variability analysis2015Conference paper (Other academic)
  • 28.
    Abtahi, Farhad
    et al.
    KTH-School of Technology and Health.
    Lu, Ke
    KTH-School of Technology and Health.
    Guangchao, Li
    KTH-School of Technology and Health.
    Rödby, Kristian
    University of Borås, Faculty of Textiles, Engineering and Business.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    A Knitted Garment using Intarsia Technique for Heart Rate Variability Biofeedback: Evaluation of Initial Prototype.2015Conference paper (Other academic)
  • 29. Abtahi, Farhad
    et al.
    Snäll, Jonathan
    Aslamy, Benjamin
    Abtahi, Shirin
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Lindecrantz, Kaj
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Biosignal PI, an Affordable Open-Source ECG and Respiration Measurement System2015In: Sensors, E-ISSN 1424-8220, Vol. 15, no 1, p. 93-109Article in journal (Refereed)
    Abstract [en]

    Bioimedical pilot projects e.g., telemedicine, homecare, animal and human trials usually involve several physiological measurements. Technical development of these projects is time consuming and in particular costly. A versatile but affordable biosignal measurement platform can help to reduce time and risk while keeping the focus on the important goal and making an efficient use of resources. In this work, an affordable and open source platform for development of physiological signals is proposed. As a first step an 8–12 leads electrocardiogram (ECG) and respiration monitoring system is developed. Chips based on iCoupler technology have been used to achieve electrical isolation as required by IEC 60601 for patient safety. The result shows the potential of this platform as a base for prototyping compact, affordable, and medically safe measurement systems. Further work involves both hardware and software development to develop modules. These modules may require development of front-ends for other biosignals or just collect data wirelessly from different devices e.g., blood pressure, weight, bioimpedance spectrum, blood glucose, e.g., through Bluetooth. All design and development documents, files and source codes will be available for non-commercial use through project website, BiosignalPI.org.

  • 30. Abtahi, Zhohreh
    et al.
    Millati, Ria
    Niklasson, Claes
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Ethanol production by Mucor indicus at high glucose and ethanol concentrations2010In: Minerva biotecnologica (Testo stampato), ISSN 1120-4826, E-ISSN 1827-160X, Vol. 22, no 3-4, p. 83-89Article in journal (Refereed)
    Abstract [en]

    Mucor indicus was cultivated under aerobic and anaerobic conditions to study its tolerance against high concentration of glucose up to 350 g/L and ethanol up to 120 g/L present in the medium. The fungus could grow well even in 350 g/L glucose and produce ethanol, but it was able to assimilate the entire glucose when its concentration was less than 200 g/L. On the other hand, M. indicus produced ethanol as the main product with yield and concentration up to 0.45 g/g and 73 g/L, respectively, while glycerol, its only major byproduct, was produced up to 24 g/L. However, the fungus was not so tolerant against exogenously added ethanol, and it could not grow with more than 40 g/L added ethanol to the culture. Under aerobic conditions, M. indicus displayed different morphology, switching from long filamentous to yeast-like growth forms by increasing initial glucose concentration. This implies that yeast-like growth can be induced by growing M. indicus at high glucose concentration. Under anaerobic conditions, only one yeast-like form was observed.

  • 31.
    Abtahi, Zohreh
    University of Borås, School of Engineering.
    Ethanol and glucose tolerance of M.indicus in aerobic and anaerobic conditions2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Over the last few decades, ethanol production from renewable resources has been of interest as an alternative fuel to the current fossil fuel, due to the unstable oil market and in order to decrease net emission of carbon dioxide which leads to global warming. According to analyses of DG Transport and Energy (TREN), it is not possible to reach the current biofuels directive promoting 5,75 % biofuel by the year 2010, due to the markets and technologies, but by the year 2020 achievement of 6.9% is expected. This new law will increase biofuel demand by 3,1 %. Lignocelluloses materials, which are relatively cheap and plentiful, are considered to be the main source of feedstock’s for low-cost bio-ethanol production. The general procedure to convert lignocelluloses material to bioethanol is hydrolysis of the hemicelluloses and the cellulose to its monomer sugars, fermentation and distillation. Bacteria, yeasts and filamentous fungi are able to ferment hydrolysates from different plants and convert it to bioethanol. Mucor indicus is a filamentous fungus; it is able to utilize a wide range of hexoses, phentoses and disaccharides (cellobiose) in order to produce ethanol. The Ethanol yield and productivity of this microorganism from hexoses are as same as Saccharomyces cerevisiae. But the reason that it is one of the candidates for ethanol production is the fungus ability to utilize xylose. The cell wall of M.indicus contains significant quantity of chitosan/chitin which can be easily extracted. Chitosan is the deacetylated products of chitin. They have many applications in chemistry, biotechnology, medicine, veterinary, dentistry, agriculture, food processing, environmental protection, water purification, cosmetic and textile industries. The results of the current work show that the glucose concentration in the medium had a great impact on the lag phase, glucose consumption and ethanol production in both aerobic and anaerobic conditions. The lag phase increased as the initial concentration of glucose increased. While the glucose concentration increased above 190 g/l in the medium the glucose consumption and ethanol production decreased in both aerobic and anaerobic conditions. The glucose tolerance of M.indicus in both aerobic and anaerobic condition is about 190 g/l and in the anaerobic condition the ethanol tolerance of this fungus is around 70 g/.

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  • 32.
    Abugharbia, Ahmad
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Cabdalla, Abubakar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effektivisering av CE-märkningsprocessen i framtagning av nya maskiner2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to fulfill the intention of the thesis, three questions have been developed. To answer these questions, data collection has been done which has consisted of a combination of qualitative and quantitative methods. Qualitative method was carried out in the form of semi- structured interviews to investigate respondents' views on the process and identify problems. Quantitative method was carried out in the form of scientific articles, documentation and literature study to collect data in the form of relevant theories and examine internal documents from the company.

    The results of the study show that the CE marking process is made up of several interdependent steps. LEAN tools and methods can be applied in the process to achieve efficiency. In addition, the participation and involvement of project team members can contribute to an improvement in the flow of information and better quality of information exchanged during the process.

    This work contributes theoretically by applying the LEAN philosophy to the CE marking process and practically by suggesting methods to make the process more effective and minimize the remaining work for CE marking at the customer. What is unique about this study is the application of the LEAN philosophy to the CE marking process in the automation industry, which opens new opportunities for improvements and increased efficiency in the field.

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    Effektivisering av CE-märkningsprocessen i framtagning av nya maskiner
  • 33. Abylaev, Mansur
    Kyrgyz textile companies’ resilience features in the post-Soviet regionalization processes2013Conference paper (Refereed)
    Abstract [en]

    The Kyrgyz textile industry is a fast growing sector since the last decade. The combination of international market conjuncture and low input factors were the main reasons for the development of the textile sector. Legal and political modification of the international trade system is a risk for the whole industry's resilience. The purpose of the paper is to identify the vulnerable points of doing business in the context of economic transformation from planned Soviet to free market economy.

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  • 34.
    Adams, Zechariah
    et al.
    University of Borås, School of Engineering.
    Shadram, Farshid
    University of Borås, School of Engineering.
    Köldbryggor i kantbalkar UNORM/DAVID-322011Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    En köldbrygga uppstår i en byggnadsdel vars isoleringsförmåga är lägre än omslutande material. Detta innebär att värmeförlusterna ökar och att den varma ytan blir lokalt kallare, vilket kan leda till nedsmutsning, mögel och kondensation. I examensarbetet har vi inriktat oss på grundkonstruktioner, närmare bestämt L-element med både lätt och tung vägg som komplement. I rapporten framgår hur vi räknat genom handberäkning och med hjälp av UNORM, ett datorprogram för beräkning av köldbryggor. För att redovisa resultatet jämförs handberäkningen med datorberäkningen, dels för att kontrollera resultatet och se skillnaden samt att se om det finns risk för mögel och kondensation med de olika L-elementen.

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  • 35.
    Adekunle, K.
    et al.
    University of Borås, School of Engineering.
    Cho, S.-W.
    University of Borås, School of Engineering.
    Ketzscher, R.
    Skrifvars, M.
    University of Borås, School of Engineering.
    Mechanical properties of natural fiber hybrid composites based on renewable thermoset resins derived from soybean oil, for use in technical applications2012In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 124, no 6, p. 4530-4541Article in journal (Refereed)
    Abstract [en]

    Natural fiber composites are known to have lower mechanical properties than glass or carbon fiber reinforced composites. The hybrid natural fiber composites prepared in this study have relatively good mechanical properties. Different combinations of woven and non-woven flax fibers were used. The stacking sequence of the fibers was in different orientations, such as 0°, +45°, and 90°. The composites manufactured had good mechanical properties. A tensile strength of about 119 MPa and Young's modulus of about 14 GPa was achieved, with flexural strength and modulus of about 201 MPa and 24 GPa, respectively. For the purposes of comparison, composites were made with a combination of woven fabrics and glass fibers. One ply of a glass fiber mat was sandwiched in the mid-plane and this increased the tensile strength considerably to 168 MPa. Dynamic mechanical analysis was performed in order to determine the storage and loss modulus and the glass transition temperature of the composites. Microstructural analysis was done with scanning electron microscopy.

  • 36.
    Adekunle, K.
    et al.
    University of Borås, School of Engineering.
    Cho, S.-W.
    University of Borås, School of Engineering.
    Patzelt, C.
    Blomfeldt, T.
    Skrifvars, M.
    University of Borås, School of Engineering.
    Impact and flexural properties of flax fabrics and Lyocell Fiber reinforced bio-based thermoset for automotive and structural applications2012Conference paper (Refereed)
  • 37.
    Adekunle, K.
    et al.
    University of Borås, School of Engineering.
    Ghoreishi, R.
    Ehsani, M.
    Cho, S.-W.
    University of Borås, School of Engineering.
    Skrifvars, M.
    University of Borås, School of Engineering.
    Jute fiber reinforced methacrylated soy bean oil based thermoset composites prepared by vacuum injection molding technique2012In: Journal of Biobased Materials and Bioenergy, ISSN 1556-6560, E-ISSN 1556-6579, Vol. 6, no 2, p. 172-177Article in journal (Refereed)
    Abstract [en]

    Bio-based composites based on soybean oil thermoset resin were manufactured with vacuum injection molding technique. Methacrylated soybean oil (MMSO) was processed with vacuum injection molding technique without blending with styrene. The composites produced had comparatively good mechanical properties like jute composite reinforced acrylated epoxidised soybean oil (AESO) resin blended with styrene. Although the tensile strength of the jute reinforced AESO composites are slightly higher than the jute reinforced MMSO composites which was attributed to blending of AESO with styrene. However, the difference in Youngs' modulus was negligible because they have approximately equal stiffness between 2.6 GPa and 2.8 GPa. The jute reinforced AESO composites showed relatively higher flexural strengths and moduli than the MMSO counterparts. This difference was also attributed to the blending of AESO with reactive diluent such as styrene. In order to determine the dimensional stability of the composite manufactured, water absorption test was carried out and the conclusion was that the moisture uptake of the jute reinforced composites was the same, this was expected.

  • 38.
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Bio-based Composites from Soybean Oil Thermosets and Natural Fibers2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In order to reduce over-dependency on fossil fuels and to create an environment that is free of non-degradable plastics, and most importantly to reduce greenhouse gas emission, bio-based products are being developed from renewable resources through intense research to substitute conventional petrochemical-based plastics with renewable alternatives and to replace synthetic fibers with natural fibers. Many authors have done quite a lot of work on synthesizing polymers from renewable origin. Polylactic acid (PLA) has been developed and characterized, and it was found that it has enormous potential and can serve as an alternative to conventional thermoplastics in many applications. Modification of the plant oil triglycerides has been discussed by many authors, and research is still going on in this area. The challenge is how to make these renewable polymers more competitive in the market, and if possible to make them 100% bio-based. There is also a major disadvantage to using a bio-based polymer from plant oils because of the high viscosity, which makes impregnation of fibers difficult. Although natural fibers are hydrophilic in nature, the problem of compatibility with the hydrophobic matrix must be solved; however, the viscosity of the bio-based resin from plant oils will complicate the situation even more. This is why many authors have reported blending of the renewable thermoset resin with styrene. In the process of solving one problem, i.e reducing the viscosity of the renewable thermoset resin by blending with reactive diluents such as styrene, another problem which we intended to solve at the initial stage is invariably being created by using a volatile organic solvent like styrene. The solution to this cycle of problems is to synthesize a thermoset resin from plant oils which will have lower viscosity, and at the same time have higher levels of functionality. This will increase the crosslinking density, and they can be cured at room temperature or relatively low temperature. In view of the above considerations, the work included in this thesis has provided a reasonable solution to the compounded problems highlighted above. Three types of bio-based thermoset resins were synthesized and characterized using NMR, DSC, TGA, and FT-IR, and their processability was studied. The three resins were subsequently reinforced with natural fibers (woven and non-woven), glass fibers, and Lyocell fiber and the resulting natural fiber composites were characterized by mechanical, dynamic mechanical, impact, and SEM analyses. These composites can be used extensively in the automotive industry, particularly for the interior components, and also in the construction and furniture industries. Methacrylated soybean oil (MSO), methacrylic anhydride-modified soybean oil (MMSO), and acetic anhydride-modified soybean oil (AMSO) were found to be suitable for manufacture of composites because of their lower viscosity. The MMSO and MSO resins were found to be promising materials because composites manufactured by using them as a matrix showed very good mechanical properties. The MMSO resin can completely wet a fiber without the addition of styrene. It has the highest number of methacrylates per triglyceride and high crosslink density.

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  • 39.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Cho, Sung-Woo
    University of Borås, School of Engineering.
    Patzelt, Christian
    Blomfeldt, Thomas
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Impact and flexural properties of flax fabrics and Lyocell fiber-reinforced bio-based thermoset2011In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 30, no 8, p. 685-697Article in journal (Refereed)
    Abstract [en]

    A bio-based thermoset resin was reinforced with flax fabrics and Lyocell fiber. The effect of different weave architectures was studied with four flax fabrics with different architectures: plain, twill (two different types), and dobby. The effect of the outer ply thickness was studied and characterized with flexural and impact testing. Composites manufactured with plain weave reinforcement had the best mechanical properties. The tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength were 280 MPa, 32 GPa, 250 MPa, 25 GPa, and 75 kJ/m2, respectively. Reinforcements with twill-weave architecture did not impart appreciable flexural strength or flexural modulus even when the outer thickness was increased. Plain- and dobby (basket woven style)-weave architectures gave better reinforcing effects and the flexural properties increased with an increase in outer thickness.Water absorption properties of the composites were studied and it was observed that the hybridization with Lyocell fiber reduced the water uptake. Fieldemission scanning electron microscopy was used to study the micro-structural properties of the composites.

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  • 40.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Ketzscher, Richard
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    High performance natural fibre hybrid composites based on biobased thermoset resins for use in technical applications2009Conference paper (Other academic)
    Abstract [en]

    Health related issues, stringent environmental protection policies, search for cost effective and alternative materials and quest for renewability, sustainability and high performance materials for technical applications has led to an intense research in manufacturing biobased composites which are based on renewable thermosetting resins and natural fibres. The combination of biobased thermosetting resins with two different natural fibre reinforcements could lead to improved mechanical properties of the composite. Biobased thermoset polymers are comparable to the synthetic thermosetting polymers from petrochemicals. In this study, two different biobased resins were used as matrix and both non woven flax fibre and woven flax fabric were combined as reinforcements. The composites were made by compression moulding process. The fibres were hand laid-up and impregnation was done manually. The curing temperature was 170°С and at 40 bar. The stacking sequence of the fibres was in different orientations such as 0º, +45º and 90º. The manufactured hybrid composites have high tensile strength and stiffness and the flexural strength and modulus was also high. These composites can compete favourably with glass fibre reinforced composites in terms of strength and stiffness.1, 2 A tensile strength of about 119 MPa and Young’s modulus of 13.8 GPa was achieved, while the flexural strength and modulus is about 201 MPa and 24 GPa respectively. For the purpose of comparison, composites were made with the combination of woven fabric and e-glass fibre. One ply of an e-glass fibre mat was put in the mid-plane and this increased the tensile strength considerably up to 168 MPa. Some of the composites were made with the resin blended with styrene and the results show a higher modulus.

  • 41.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Patzelt, Christian
    Kalantar, Adib
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mechanical and Viscoelastic Properties of Soybean Oil Thermoset Reinforced with Jute Fabrics and Carded Lyocell Fiber2011In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 122, no 5, p. 2855-2863Article in journal (Refereed)
    Abstract [en]

    Composites and hybrid composites were manufactured from renewable materials based on jute fibers, regenerated cellulose fibers (Lyocell), and thermosetting polymer from soybean oil. Three different types of jute fabrics with biaxial weave architecture but different surface weights, and carded Lyocell fiber were used as reinforcements. Hybrid composites were also manufactured by combining the jute reinforcements with the Lyocell. The Lyocell composite was found to have better mechanical properties than other composites. It has tensile strength and modulus of about 144 MPa and 18 GPa, respectively. The jute composites also have relatively good mechanical properties, as their tensile strengths and moduli were found to be between 65 and 84 MPa, and between 14 and 19 GPa, respectively. The Lyocell-reinforced composite showed the highest flexural strength and modulus, of about 217 MPa and 13 GPa, respectively. In all cases, the hybrid composites in this study showed improved mechanical properties but lower storage modulus. The Lyocell fiber gave the highest impact strength of about 35 kJ/m2, which could be a result of its morphology. Dynamic mechanical analysis showed that the Lyocell reinforced composite has the best viscoelastic properties.

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    fulltext
  • 42.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Patzelt, Christian
    Kalantar, Adib
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mechanical properties of renewable soyean oil thermoset reinforced with jute fabricsand lyocell fiber2011Conference paper (Refereed)
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  • 43.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthesis of reactive soybean oils for use as thermoset resins in composites.2007Conference paper (Refereed)
  • 44.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Bakare, Fatimat
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Bio-based thermoset resins from soybean and linseed oils for structural composites2011Conference paper (Refereed)
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  • 45.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites2009In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 115, no 6, p. 3137-3145Article in journal (Refereed)
    Abstract [en]

    Biobased thermosets resins were synthesized by functionalizing the triglycerides of epoxidized soybean oil with methacrylic acid, acetyl anhydride, and methacrylic anhydride. The obtained resins were characterized with FTIR, 1H-NMR, and 13C-NMR spectroscopy to confirm the functionalization reactions and the extent of epoxy conversion. The viscosities of the methacrylated soybean oil resins were also measured for the purpose of being used as a matrix in composite applications. The cross-linking capability was estimated by UV and thermally initiated curing experiments, and by DSC analysis regarding the degree of crosslinking. The modifications were successful because up to 97% conversion of epoxy group were achieved leaving only 2.2% of unreacted epoxy groups, which was confirmed by 1H-NMR. The 13C-NMR confirms the ratio of acetate to methacrylate methyl group to be 1 : 1. The viscosities of the methacrylated soybean oil (MSO) and methacrylic anhydride modified soybean oil (MMSO) were 0.2 and 0.48 Pas, respectively, which indicates that they can be used in resin transfer molding process.

  • 46.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthesis of reactive soybean oils for use as biobased thermoset resins in structural natural fibre composites2008Conference paper (Refereed)
  • 47.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthetic modification of reactive soybean oils for use as biobased thermoset resins in structural natural fiber composites2008Conference paper (Other academic)
  • 48.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthetic modification of reactive soybean oils for use as biobased thermoset resins in structural natural fiber composites2008In: Polymer Preprints, ISSN 0551-4657, Vol. 49, no 1, p. 279-Article in journal (Refereed)
  • 49.
    Adelsten, Tiffany Min
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Gakic, Sevala
    University of Borås, Faculty of Textiles, Engineering and Business.
    Minska styvheten och öka stickbarheten för pappersgarn tvinnat med viskosgarn2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To achieve the Global Goals 2030, we as a society will need to significantly reduce our global ecological footprint. The textile industry of today accounts for a significant part of this ecological footprint both through use of land, climate-affecting emissions, soil- and water pollution and more. This has led to an increasing demand for more sustainable solutions in the textile industry. There are a number of types of yarn that have a lower environmental impact. Many of them however have quite a lower market share today. One of these materials that we chose to take a closer look at was paper yarn, which in it’s production consumes significantly less resources than other usual yarns on the market (Fakirov 2015). However, the development of use of paper yarn has so far been limited by its rigidity and poor knitability. This project has aimed to try to reduce the stiffness of the paper yarn and increase its knitability. This was done by twisting different numbers of twist/meter of viscose yarn, around the paper yarn. We twisted a single-threaded 17 tex hemp viscose yarn around the paper yarn at 100, 300 and 500 twist/meter with the core-spun method. Then the yarn was treated with fatty acid to counteract the brittleness and prepare it for knitting. The yarn was knitted on a circular knitting machine with a single jersey stitch. Tests done on yarn were tensile testing and friction testing. The tricot also was subjected to tensile testing (rupture), stiffness testing and abrasion testing. Viscose mixed yarn knitwear was found to have a softer feeling of the fabric compared to just knitted paper yarn. During tensile testing of tricot, it was found that a larger proportion of viscose adds more strength as higher pressure was needed as well as time to achieve a stretch in the tricot. Twisting with different twists of viscose yarn has been shown to cause small differences in knitability as there were occasional holes in the paper yarn knit during the knitting process. Yarns of 300 and 500 twist/meter, however, had the most weak points without showing visible holes on the fabric. Differences in the stiffness of the tricot were noticeable between all the fabrics, however, it was not possible to obtain useful results from the stiffness tester as this test method was probably unsuitable for the selected tricot binding because the fabric rolled. 

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    fulltext
  • 50.
    Aden, Subeyr
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Singh Sandhey, Akash
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effektivisering av godsmottagning: En fallstudie om effektivisering inom godsmottagningen på Plasman Group2021Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Inefficient material handling has a direct impact on the company's costs, so it is important to map different processes in the business. The unnecessary activities contribute to the need to implement continuous improvements. Based on the theories on which the study is based, it consists of Logistics, Lean, Materials Management, Warehouse Layout and ABC analysis. The goal is to find improvement suggestions that are linked to waste. Initially, a material flow chart was performed at the goods reception to investigate what processes look like in operations using standard symbols and figures used in logistics contexts.

    The focus is on utilizing storage areas and the waste that arises in the event of obstacles. The implementation of the study could be performed with interviews and observations that contributed to a more constructive work. There was a standardized way of working the doll was the bearing surface and the waste that was the problem. The studied area in the goods reception had four wastes that were identified. These are the following transports, rework, movements and warehouses. ABC analysis was performed to give the company a good knowledge of material handling.

    Using data from the company designed an ABC classification to help with inventory management. The A-classification accounts for 70.42% of the total articles, B accounts for 24.47% and C which stands for 5.11%. It turned out that the C-items are not very important, while A and B are in-demand items that quickly disappear from stock. The study concludes with improvement proposals linked to the two issues that enable cost savings from an efficiency perspective.

    The authors' conclusion of the study is that there are good conditions for the company to implement the improvement proposals.

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    fulltext
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