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  • 151.
    Bohlén, Martin
    et al.
    University of Borås, School of Engineering.
    Bolton, Kim
    University of Borås, School of Engineering.
    Inducing the β-phase of poly(vinylidene fluoride): a review2014In: Annual Review of Nanoscience and Nanotechnology, ISSN 2159-9688, Vol. 1, no 1Article in journal (Refereed)
    Abstract [en]

    Poly(vinylidene fluoride) (PVDF) is a versatile material with numerous applications in many fields of industry and science. The extent of applications, ranging from approved contact materials in the food industry to monitors for respiration and heart-rate in medicine, drives the research and development by the materials science community. The largest limiting factor when using PVDF in applications where its piezo- and pyroelectricity is important, is the amount of the highly polar crystalline β-phase in the material. PVDF is polymorphic and usually crystallizes from melt or solution into the non-polar α-phase, which is of little use in piezoelectric applications. Many studies have therefore aimed at increasing the amount of the β-phase crystal structure in the material. Cold drawing of α-phase PVDF, poling in high electric fields, copolymerization with trifluoroethylene, and inclusion of different types of additives to PVDF have been studied using both experimental and computational techniques. This review presents the current status and understanding of these processes, and summarizes results from previous studies. © Global Scientific Publishers 2015.

  • 152.
    Bohlén, Martin
    et al.
    University of Borås, School of Engineering.
    Satyanarayana, Kavitha Chelakara
    Bolton, Kim
    University of Borås, School of Engineering.
    Computational Studies of Poly(vinylidene fluoride)-Single Wall Carbon Nanotube Systems2013In: Journal of Computational and Theoretical Nanoscience, ISSN 1546-1955, E-ISSN 1546-1963, Vol. 10, no 6, p. 1317-1325Article in journal (Refereed)
    Abstract [en]

    First principles and molecular mechanics methods have been used to study poly(vinylidene fluoride)—single wall carbon nanotube systems. First principles calculations (Møller-Plesset second order perturbation theory and density functional theory with B3LYP exchange correlation functional with and without dispersion correction) using short poly(vinylidene fluoride) segments and short hydrogen-capped single wall carbon nanotubes show that the polymer segments prefer to have the β-rather than the β-conformation both in the absence and presence of the single wall carbon nanotube. The lowest energy structure is obtained when the poly(vinylidene fluoride) has an β-conformation and is located parallel to the single wall carbon nanotube wall. In contrast to the Dreiding and Universal force fields, the COMPASS force field predicts the structures containing the β-conformation of poly(vinylidene fluoride) to be the lowest in energy in agreement with first principles results. The COMPASS force field was consequently used in preliminary studies of a longer poly(vinylidene fluoride) chain and a longer single wall carbon nanotube using molecular dynamics.

  • 153.
    Bohlén, Martin
    et al.
    University of Borås, School of Engineering.
    Yaghooby, Haleh
    Airola, Karri
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Film Extrusion of Hydroxyapapatite and β-Tricalciumphosphate Functionalized Polyactide Polymers for Biomedical Implants2010Conference paper (Other academic)
  • 154.
    Bolin, Agnes
    et al.
    University of Borås, Faculty of Librarianship, Information, Education and IT.
    Petersson, Julia
    University of Borås, Faculty of Librarianship, Information, Education and IT.
    Sjöholm, Johanna
    University of Borås, Faculty of Librarianship, Information, Education and IT.
    Skydd av elektroniska patientjournaler – en studie om faktorer för olovlig läsning2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There are many health professionals that require access to health records in today’s health care. This means that information must be easily accessible when needed. Meanwhile the patient´s integrity is a very important issue so no personal sensible information leaks. One problem is that health professionals can read journal of patients in health care information systems without permission.The study researches the tension between two aspects, how health professionals act in health care information systems compared to how the system is secure. One aspect is how nursing staff in Sweden is prone to read journals of patients consciously, thus acting unethical. The other aspect is how the information system within Swedish health care can find the balance between easily user accesses and adequately protected against internal intrusions. The research question is to identify underlying factors how health professionals ethical approach is to illicit reading of electronical health records, in relation to how the systems are protected against these internal intrusions.The conduct of study is through a flexible method approach because the focus is to looking for context and interprets the result. In order to get a good foundation made a pilot study by several interviews. The aim of the pilot study was to expand knowledge regarding health information systems. Laws and regulations, policies and procedures in health care information systems has been considered, focused in Västra Götaland County in Sweden. To find out the nursing staff attitudes to internal intrusion were questionnaires sent out. As the subject of the study can be perceived as sensitive, the authors have made clear to the respondents that it was completely anonymous, considering the case of illegal behavior in the workplace.The finding of the study shows even though the majority of the survey´s respondents remain within the regulations of health care relating to read electronical health records, some of the respondents still shows tendencies to partly abandon them. The authors considered to prevent these tendencies that controls of log history in health care systems should increase and be made by independent auditors. This also for the aim to protect patients and reach more security. The study aims to health professionals and their managers to provide information on the behavior and its risk for patient’s integrity and the public lack of confidence.

  • 155.
    Bolton, Kim
    University of Borås, School of Engineering.
    Modelling carbon nanotube growth2008Conference paper (Other academic)
  • 156.
    Bolton, Kim
    University of Borås, School of Engineering.
    Simulations of water, metal and carbon clustering2008Conference paper (Other academic)
  • 157.
    Bolton, Kim
    et al.
    University of Borås, School of Engineering.
    Börjesson, Anders
    University of Borås, School of Engineering.
    Computational studies of single-walled carbon nanotube growth2011In: SNIC Progress Report (2008-2009), p. 40-46Article in journal (Other academic)
    Abstract [en]

    Allocation of time on the Swedish national supercomputing facilities since 2000, as well as support from other sources, has allowed us to perform computational studies on a wide variety of systems. These include properties and growth of carbon nanotubes [1–36], icecatalysed reactions of importance to stratospheric ozone depletion[37], calculations of vapour-liquid, liquid-liquid and vapour-liquid-liquid phase equilibrium of single, binary and ternary component systems[38], and, more recently, carbonaceous polymer nanocomposites and cellulose decomposition. More details of these projects are available at the web page given above.

  • 158.
    Bolton, Kim
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    De Mena, Barbara
    ttz Bremerhaven.
    Schories, Gerhard
    ttz Bremerhaven.
    Sustainable Management of Solid Waste2016In: Resource Recovery to approach zero municipal wastes / [ed] M. J. Taherzadeh and T. Richards, CRC Press, 2016, p. 23-41Chapter in book (Refereed)
  • 159.
    Bolton, Kim
    et al.
    University of Borås, School of Engineering.
    Ding, F.
    Börjesson, Arne
    Zhu, W.M.
    Duan, H.M.
    Harutyunyan, A.R.
    Curtarlo, S.
    Computational Studies of Catalytic Particles for Carbon Nanotube Growth2009In: Journal of Computational and Theoretical Nanoscience, ISSN 1546-1955, E-ISSN 1546-1963, Vol. 6, no 1, p. 1-15Article in journal (Refereed)
    Abstract [en]

    We review our computational studies of the melting temperatures and mechanisms of iron and iron-carbide clusters. Both isolated and supported clusters have been considered, and substrates with different shapes or pores have been simulated. It has been seen, for example, that the surface curvature—or local surface curvature—of the particle plays a dominant role in the melting mechanism and temperature. It has also been observed that the melting mechanism for small clusters is different to that of larger clusters.

  • 160.
    Bolton, Kim
    et al.
    University of Borås, School of Engineering.
    Zhu, Wuming
    Börjesson, Anders
    Progress in understanding controlled single-wall carbon nanotube growth from computer simulations2012In: Journal of Computational and Theoretical Nanoscience, ISSN 1546-1955, E-ISSN 1546-1963, Vol. 9, no 6, p. 819-825Article in journal (Refereed)
    Abstract [en]

    Density functional theory based on the PW91 and PBE exchange-correlation functionals was used to study processes that are expected to play a key role in single-walled carbon nanotube (SWNT) growth and continued growth. It is shown that Ni clusters adapt their shape to the shape of the SWNT end to which they are attached. The results also show that the presence of SWNTs affects Ostwald ripening of the catalyst metal clusters and that, under certain conditions, the net diffusion may be from larger to smaller clusters. Also, Ostwald ripening may affect the chiral distribution of the SWNTs.

  • 161.
    Bondesson, Amy
    et al.
    University of Borås, Swedish School of Textiles.
    Persson, Anna
    University of Borås, Swedish School of Textiles.
    Worbin, Linda
    University of Borås, Swedish School of Textiles.
    Costumes and Wallhanging2009Other (Other academic)
    Abstract [en]

    This work deals with Smart Textiles in interaction with the body. We design textiles and outfits as tools that can influence fashion and textile design. Central to our work is that artistic envisioning can point to new possibilities and values, in which we want to stress the importance of combining traditional materials and methods with contemporary and future functions in order to obtain sustainable ideas. The film documents a performance, where dancers create a link between the body, the textile material and the room surrounding the body. The textile material and the garment are to inspire movement that, in turn, creates development; when a person wears the garment and moves in a certain way or touches other persons, the visual expression of the room changes through an electronic signal. In this case, the colour of the pattern of the textile draping changes to the static pattern that is printed on the person’s outfit. The point of the show was to show possibilities of non-static and dynamic design through scenic expression.

  • 162.
    Bondesson, Amy
    et al.
    University of Borås, Swedish School of Textiles.
    Worbin, Linda
    University of Borås, Swedish School of Textiles.
    Persson, Anna
    University of Borås, Swedish School of Textiles.
    Textile dimensions: an expressive textile interface2009Conference paper (Other academic)
    Abstract [en]

    Computation and new materials are entering the world of textiles, challenging our view on the textile material. As new techniques and electrically conductive fibres enable the design of textile circuits and computationally active textiles [2], the areas of smart textile design and interaction design start to merge. Wearable computing [cf.1], the notion of moving computational tools directly onto the body, might have been the first approach to bring computation technology closer to the area of clothing.. In an approach to investigate new enhanced forms of expressional interaction through textiles, the relationship between tactile and visual aesthetical properties are explored in the present paper. Textile Dimensions, an interactive set of textiles, shows how clothes and textiles become interfaces themselves, able to sense and react on external stimuli in expressive ways.

  • 163. Borg, Rickard
    AGILT: undersökning av införandet av Scrum i företag med avseende på kommunikation, motivation och teamwork2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Scrum is a framework used for the entertainment and development of complex systems (Schwaber & Sutherland 2016) and one of the most common agile project management methods at the present time. Agile methods have many advantages over traditional methods as they are more flexible. Many companies that previously used traditional methods, therefore choose to replace their old structure and its methods, to implement agile project management methods instead. This is a demanding task, especially for a larger company and imposes high demands on both management and other staff. Scrum is a framework that is highly dependent on communication. When introducing Scrum, it may be difficult to achieve the level of communication required to promote teamwork. Team members may in some cases need motivation to communicate and contribute to well-functioning teamwork.

    The purpose of the study is to investigate the importance of continuous communication, motivation and teamwork among team members in relation to the introduction of Scrum into a larger company. In this study, a qualitative approach was used since data collection took place through semi-structured interviews with open qualitative research questions. Theoretical framework in the study is based on theories of agile methodology, types of agile project management methods, motivation for the introduction of agile project management methods, challenges associated with the introduction of these methods as well as on Scrum roles, activities and artifacts. The reason for the chosen theories is to gain an overview of agile project management methods, especially Scrum, and to investigate how continuous communication is to be secured in teams when introducing Scrum through questions about respondents' personal perceptions regarding motivation categories and teamwork characters. The study results demonstrate that regular meetings, training and exercises while maintaining strong team cohesion encourage continuous communication. Continuously, intrinsic motivation is the most fundamental aspect of a well-functioning team and important for promoting communication in the team and vice versa. The results of the study indicate that in order to establish effective teamwork, continuous communication and motivation between team members are required.

  • 164.
    Brants, Rasmus
    et al.
    University of Borås, Faculty of Librarianship, Information, Education and IT.
    Johansson, Alexander
    University of Borås, Faculty of Librarianship, Information, Education and IT.
    Datalogiskt tänkande: arbetsgivarens preferenser2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden and the rest of the world are constantly evolving in the digital aspect. Every yearmore technology is being implemented in all the fields which make the technology in controlof all the working fields. These changes have made Sweden and other countries to start withprogramming in the elementary school. This is to develop the individual’s computationalthinking. In this thesis, computational thinking is researched as a property of an individualand how employers prioritize computational thinking at a potential employment within theirbusiness as a software developer. Through interviews and surveys the researches havecollected data and constructed their own categories from programming and computationalthinking which was used in comparison with collected data from different employers. Thisstudy has shown that employers actually prefer computational thinking over programmingskillswhich support the recent implementation of computational thinking.

    This thesis is unique because none or very few previous researchers with a study revolvingcomputational thinking where categorizes have been used to compare the two different fields.The researches strongly believe that academic stakeholders within computer science andorganizations that uses software developing can have great use of this thesis’ results. Thisstudy enlightens a unique result which most likely has not been conducted before. Potentialconsequences of this study are that the authors hope that computational thinking will acquiremore attention. A clear knowledge grant of the previous research about computationalthinking is being presented in this study which can affect the future research andimplementation of the term computational thinking.

  • 165.
    Bresky, Erik
    et al.
    University of Borås, Swedish School of Textiles.
    Edström, Susanne
    University of Borås, Swedish School of Textiles.
    Ledendal, Marie
    University of Borås, Swedish School of Textiles.
    Nordqvist, Mats
    University of Borås, Swedish School of Textiles.
    Hallnäs, Lars
    University of Borås, Swedish School of Textiles.
    Smart Textiles2008In: The Nordic Textile Journal 2008, Special Edition Smart Textiles, p. 2-9Article in journal (Other academic)
  • 166. Brunell, Mats
    et al.
    Appelkvist, Rolf
    University of Borås, School of Business and IT.
    Digitalt PrototypLabb: Visualiseringslabb. Förstudie för genomförande2011Report (Other academic)
    Abstract [sv]

    Tidigare förstudier har visat att det finns ett behov av att skapa en mötesplats för forskare, utvecklare, innovatörer, konsumenter, finansiärer och övriga intressenter. Hypotesen har varit att denna mötesplats skulle ligga till grund för att ta fram fler och mer kvalitativa produkter och tjänster och ”träffa mer rätt” vad gäller design tidigt i utvecklingsprocessen. Vad är ett Digitalt Prototyplabb – Visualiseringslabb? Ett Prototyplabbet eller Visualiseringslabb är rent rumsligt och tekniskt ett rum med teknik för visualisering, kommunikation och simulering. Genom datorstöd kan olika processer för innovations- och produktutveckling. Genom teknikstödet skall bättre förståelse för olika problemställningar visas, kommuniceras om och simuleras. Labbet är en pusselbit i en ”mjuk” infrastruktur som omfattar processkunskap och innovationsmetodik i ett bredare perspektiv, detta belyses nedan. Med visualisering avses här att bildligt/grafiskt framställa idéer och begrepp för fortsatt bearbetning. Genom att bildligt/grafiskt konkretisera tankar och idéer tänkes tiden mellan aning och bearbetad idé och även artefakt/produkt, vare sig detta är en vara eller en tjänst, kunna kortas. Rollen för ett Digitalt Prototyplabb Det digitala prototyplabbet som denna rapport behandlar skall ses som en resurs i en process vars syfte är att ta fram Innovativa tjänster eller produkter. Det digitala prototyplabbet skall vara en mötesplats för de ovan nämna intressenterna där många skarpa hjärnor med olika perspektiv samarbetar i att ta fram en produkt eller tjänst med bra kvalité. Det som gör denna variant av labb/”think-tank” unik är att användarna har digitala hjälpmedel samt en vetenskaplig innovativ metod till hjälp. Det digitala prototyplabbet skall dessutom genom rätt utformad presentations- och kommunikationsteknik underlätta design och konstruktionsfasen. Dessa verktyg skall, tillsammans med den kunskap de personer som deltar i processen besitter, ge större förutsättning för att undvika fel och brister samt hitta fler innovativa användningsområden för den tänkta produkten. Det i sin tur bidrar till att produktutvecklingsprocessen tar kortare tid och därmed blir mer ekonomisk. Redan idag använder många företag denna typ av process för s.k. ”In-house” och ”In-the-box” framtagning av produkter samt förbättring/vidareutveckling av dessa produkter. Många gånger saknas dock de hjälpmedel som nämns ovan vilket kan vara en nackdel för produktutvecklingsprocessen. Potentialen för näringslivsutveckling I korthet är potentialen för det digitala prototyplabbet och dess process följande: • Förkorta produktutvecklingscykeln • Förbättra exempelvis tjänster och produkter för företag – ”In-the-Box” • Förbättra förmågan till innovation, exempelvis utgående från nya materials potential • Införa processtekniska lösningar inom flera områden exempelvis logistik och ”waste refinery” • I samverkan med lärosäten och institut kan nya tillämpningsområden såsom transportområdet utvecklas. Potential för utbildningsområdet Det digitala prototyplabbet kan användas för projekt i existerande utbildningar och som facilitet i planerade nya utbildningar. Institutionen för Data och Affärsvetenskap vid Högskolan i Borås arbetar för närvarande med att få tillstånd ett samarbete mellan lärosäten i Kina och USA och om denna satsning bär frukt ser IDA stora möjligheter att kunna använda ett realiserat prototyplabb. Vidare ser projektgruppen en möjlighet för InnovationLab, också det vid Högskolan i Borås att få en ytterligare förstärkning av deras utvecklingsprocess vad gäller IT-projekt i samband med forskning. Potential för forskningen Det digitala prototyplabbet kan användas som en resurs för forskning och aktionsforskning för att öka förståelsen i särskilt tvärvetenskaplig forskning såsom interaktion och användargränssnitt. Området som sådant anknyter forskningsmässigt till redan pågående verksamheter inom Högskolan i Borås inom industrirelaterade aktionsforskning. Projektgruppen har under förstudien knutit kontakter med flera aktörer som ställer sig bakom metod och teknikutvecklingssamarbete. Bland dessa kan nämnas: Högskolan i Borås, Uppsala Universitet, Militärhögskolan samt troligen även Mittuniversitet med norsk partner. Generellt saknas stöd för att skapa en god kommunikation och interaktion inom grupper av individer med olika kunskaper. Vidare finns det behov av att kunna visualisera och interagera mellan olika typer av information i rummet och eventuellt till ett annat geografiskt placerat digitalt prototyplabb. Tanken är att hålla teknikstöden så generella så att olika möjligheter för innovation kan utnyttja resurserna. Processtöd kan därutöver göras för vissa utvalda metoder. På så sätt kan också företagsinterna processgenomföranden möjliggöras i det digitala prototyplabbet. De digitala tekniker som bör användas för att uppnå dessa möjligheter bör vara att installera ett multi-touch interaktionsbord för avstämning av beroende mellan ex vis: mekanisk design och elektronik eller processteg – modellering av affärsverksamheten och teknikstöden för dessa. Vidare skulle s.k smartboards utgöra bra komplement till detta multi-touch interaktionbord. Genom att ytterligare utöka det digitala prototyplabbet med 3D Skanner och 3D printer skulle ett prototyplabb kunna bli en arena för att snabba på produktutvecklingsprocessen. Vidare menar projektgruppen att genom att använda ett IT-stöd för projekthantering – informationshantering, kan utvecklingsprocessen stödjas ytterligare. Detta blir särskilt användbart när de involverade individerna arbetar i olika delar av verksamheterna och om externa aktörer skall kopplas in. Här finns interna system hos Högskolan som kan användas för elev- och interna projekt. Om företag skall acceptera extern hantering av skarpa projekt kommer andra krav på plattformar och IT-lösning in i bilden. Ett annat område som skapar ytterligare möjligheter för användarna i prototyplabbet är nya material och metoder för produktutveckling och problemlösning. De befintliga materialhanteringssystemen stödjer inte de vertikala och horisontella materialperspektiven ett prototyplabb skulle behöva. Det skulle därför behöva utvecklas ett materialhanteringssystem som stödjer de krav som personer i processen kräver. Inom Textilhögskolan pågår nu en förstudie avseende uppbyggnad av ett textilt materialbibliotek. En dialog har även öppnats med potentiell extern aktör i syfte att kunna realisera ett förbättrat materialhanteringssystem med specifikt textilt innehåll. Detta projekt är fristående, men ändå relaterat till det digitala prototyplabbet. Projektgruppen menar att potentialen för ett framtida prototyplabb är stor då det kan hjälpa utveckling av processer, teknikstöd för innovation och produktutveckling. Det digitala prototyplabbet kommer vid en realisering att utgöra en viktig pusselbit i de insatser som nu görs inom ex vis Smart Textiles, HB Ingenjörshögskolan och inom Espiras olika verksamheter. Vi ser också att detta skapar ett kitt och syfte för många av aktörernas olika egna insatser. Affärsmodellen för det digitala prototyplabbet behöver vidareutvecklas så att man kan tillföra kunskap från flera aktörer – en incitamentsmodell - allt i syfte att nå bättre produkter än om enbart kunskap inom det egna företaget eller verksamheten medverkar. Projektgruppen har genom förstudien förankrat idéer hos en kritisk massa av samarbetspartners för en framtida realisering och utveckling av både teknik och metodik i prototyplabbet. Vidare bedömer projektgruppen att finns möjligheter att finna en kärna av intresserade företag för utnyttjande av det digitala prototyplabbet. Genom realisering och användande av lämplig process kan företag gärna i samverkan med andra företag och forskning öka innovationshöjden i produkter och tjänster på många områden. Projektgruppen kan tänka sig att en realiseringsfas inleds för att göra ett försök med ett digitalt prototyplabb. Denna initiala fas för ett framtida prototyplabb avser att detaljplanera en första version av labbet och förankra affärsmodell och finansiering av Labbet hos de identifierade aktörerna inom HB, Espira/Sjuhärad. Vidare behöver ett sådant arbete ytterligare förtydliga formerna för samverkan med identifierade FoU-partners i en konsortieform.

  • 167. Buendia, Ruben
    et al.
    Seoane, Fernando
    University of Borås, School of Engineering.
    Bosaeus, Ingvar
    Gil-Pita, Roberto
    Johannsson, G
    Ellegård, Lars
    Lindecrantz, Kaj
    University of Borås, School of Engineering.
    Robustness study of the different immittance spectra and frequency ranges in bioimpedance spectroscopy analysis for assessment of total body composition2014In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, ISSN 0967-3334, Vol. 35, no 7, p. 1373-Article in journal (Refereed)
    Abstract [en]

    The estimation of body fluids is a useful and common practice for assessment of disease status and therapy outcomes. Electrical bioimpedance spectroscopy (EBIS) methods are noninvasive, inexpensive and efficient alternatives for determination of body fluids. One of the main source of errors in EBIS measurements in the estimation of body fluids is capacitive coupling. In this paper an analysis of capacitive coupling in EBIS measurements was performed and the robustness of the different immittance spectra against it tested. On simulations the conductance (G) spectrum presented the smallest overall error, among all immittance spectra, in the estimation of the impedance parameters used to estimate body fluids. Afterwards the frequency range of 10–500 kHz showed to be the most robust band of the G spectrum. The accuracy of body fluid estimations from the resulting parameters that utilized G spectrum and parameters provided by the measuring device were tested on EBIS clinical measurements from growth hormone replacement therapy patients against estimations performed with dilution methods. Regarding extracellular fluid, the correlation between each EBIS method and dilution was 0.93 with limits of agreement of 1.06 ± 2.95 l for the device, 1.10 ± 2.94 l for G [10–500 kHz] and 1.04 ± 2.94 l for G [5–1000 kHz]. Regarding intracellular fluid, the correlation between dilution and the device was 0.91, same as for G [10–500 kHz] and 0.92 for G [5–1000 kHz]. Limits of agreement were 0.12 ± 4.46 l for the device, 0.09 ± 4.45 for G [10–500 kHz] and 0.04 ± 4.58 for G [5–1000 kHz]. Such close results between the EBIS methods validate the proposed approach of using G spectrum for initial Cole characterization and posterior clinical estimation of body fluids status.

  • 168. Bukingham Shum, Simon
    et al.
    Lind, MikaelUniversity of Borås, School of Business and IT.Weigand, Simon
    Proceedings of the 2nd International Conference on the Pragmatic Web: Building Common Ground on the Web2007Collection (editor) (Other academic)
  • 169. Bydén, S.
    et al.
    Hansson, E.
    Wemmer, S.
    Arnham, E.
    Carlsson, C.
    Gibson, K.
    Svensson, J-E.
    Schmidtbauer-Crona, J.
    Sjuhärad: fiskeguide, fishing guide, angelführer.2006Report (Other academic)
  • 170. Bylund, Linda
    et al.
    Hamnebo Zetterman, Jenny
    Estetiken som funktion: En studie om hur estetiska animationer på webben påverkar användarupplevelsen2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this bachelor thesis is firstly to find out individuals' perceptions of an animation that has no other planned function than to be aesthetically appealing. Secondly, to investigate how users of a web page perceive an aesthetic animation and how this animation affects their user experience of, and dedication towards, the site. Two identical website prototypes – one with and without aesthetic animation – were was developed for use in this study. An experimental approach has been adopted and qualitative and quantitative approaches were combined in the collection of data. 13 strategically selected study participants were divided into one experiment group and one control group. The experiment group was shown the prototype with the aesthetic animation and the control group was shown the website without animation. The experiment methods consisted of observation, think-aloud and a questionnaire form. The form primarily focused on questions about the participants' perceptions and experiences of the website prototype. The results show clearly higher levels of positive user experience and levels of engagement towards the website prototype in the experiment group compared with the control group. In the experiment group, the majority of participants experienced a positive perception of the aesthetic animation and it also affected their user experiences of and levels of engagement with the website positively.

  • 171. Byvik, Joakim
    et al.
    Haji Karimian, Victor
    Informationsarkitektur, en fråga om designprinciper: En studie av Content Management Systems informationsarkitektur2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study aims to answer the questions whether Content Management Systems follow basic information architecture principles whilst designing and developing its systems. The study outlines the three basic areas within information architecture; labeling, information structure and organization, and navigation systems and establishes hypothesis based on the theory surrounding these areas. The hypothesis were also used to define the information architecture principles that we used to test the Content Management Systems WordPress, Joomla!, and Drupal on. The study shows a couple of interesting things in its analysis of the Content Management Systems. Firstly that Content management systems follow basic information architecture principles. But they do so in different ways, but also in ways that are similar to each other. The use of labels, types of navigation systems and information structure were similar between the systems. The differences showed in the underlying systems where more local navigation systems changed and the information schemes used to categorize information differed. The study concluded that Content Management Systems information architecture are designed based on established principles.

  • 172.
    Bátori, Veronika
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mostafa, Jabbari
    Srivastava, Rajiv K.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lennartsson, Patrik R
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Synthesis and characterization of maleic anhydride-grafted orange waste for potential use in biocomposites2018In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, no 3, p. 4986-4997Article in journal (Refereed)
  • 173.
    Börjesson, A.
    et al.
    University of Borås, School of Engineering.
    Zhu, W.
    Amara, H.
    Bichara, C.
    Ducastelle, F.
    Bolton, Kim
    University of Borås, School of Engineering.
    Theoretical investigation of the Nanotube-metal junction2008Conference paper (Other academic)
  • 174.
    Börjesson, Anders
    University of Borås, School of Engineering.
    Computational Studies of Metal Clusters and Carbon Nanotubes2008Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Carbon nanotubes constitute a promising candidate material in the realisation of nanoscaled electronics. This requires the ability for systematic production of carbon nanotubes with certain properties. This is called selective carbon nanotube growth. Two important aspects related to carbon nanotube growth are investigated in order to shed some light on this issue. First the melting behaviour of nanometer sized iron particles is investigated using molec- ular dynamics simulations. The iron nanoparticles studied are mounted on a porous Al2 O3 substrate in order to mimic the experimental situation during nanotube growth with the chemical vapour deposition method. This showed that the melting temperature of a cluster on a porous substrate may be lower than the melting temperature of a cluster on a flat sub- strate. This means that the catalyst particles used for nanotube growth may be liquid. In association with these studies the role of surface curvature to melting behaviour is explored further. The second presented study concerns the docking of nickel clusters to open single wall carbon nanotube ends. The motivation for this study was the possibility to continue growth of a carbon nanotube by docking of catalyst particles to its end. This work may also be of importance for the creation of electric junctions between carbon nanotubes and metal elec- trodes. This study showed that independent of whether the metal was gently put on the nanotube end or brutally forced to the end, it is the metal that adapts to the nanotube and not vice versa. For forced docking it was seen that carbon might dissolve in to the metal. This was not seen for the gently docked clusters. Carbon dissolution might affect the electronic properties of the metal (carbide) and nanotube-metal junction.

  • 175.
    Börjesson, Anders
    et al.
    University of Borås, School of Engineering.
    Bolton, Kim
    University of Borås, School of Engineering.
    First Principles Studies of the Effect of Nickel Carbide Catalyst Composition on Carbon Nanotube Growth2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 42, p. 18045-18050Article in journal (Refereed)
    Abstract [en]

    Density functional theory calculations were used to investigate the stability of single-walled carbon nanotubes (CNTs) attached to nanoparticles. The total energies and the adhesion energies between the CNTs and the nanoparticles were calculated for systems where the nanoparticles were either pure Ni or Ni carbide. It was found that the adhesion between the CNT and a pure Ni cluster is stronger than between the same CNT and a Ni carbide cluster although the energy difference was small compared to the total adhesion energies. This adhesion strength implies that CNTs are likely to remain attached to both pure Ni and Ni carbide clusters and that either pure Ni or Ni carbide clusters may be docked onto the open CNT ends to achieve continued growth or electronic contacts between CNTs and electrode materials. The system with a CNT attached to a pure Ni cluster was found to be energetically favored compared to a system containing the same CNT attached to a Ni carbide. The difference in total energy implies that a CNT should act as a sink for C atoms dissolved in the Ni carbide cluster, which means that the dissolved C atoms will be drained from the cluster, yielding a pure metal in the zero Kelvin thermodynamic limit. It is argued that this draining procedure is likely to occur even if carbon is added to the cluster at a proper rate, for example, during CNT growth.

  • 176.
    Börjesson, Anders
    et al.
    University of Borås, School of Engineering.
    Bolton, Kim
    University of Borås, School of Engineering. University of Borås, Swedish School of Textiles.
    Modelling of Ostwald ripening of metal clusters attached to carbon nanotubes2011In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 50, p. 24454-24462Article in journal (Refereed)
    Abstract [en]

    We present a model of Ostwald ripening of nanosized clusters and apply it to study the time evolution of metal particles attached to carbon nanotubes. The Ostwald ripening of metal clusters attached to carbon nanotubes differs from that of free metal clusters. While free clusters experience a rapid broadening in the size dispersion, this may be delayed by the nanotubes, which may therefore limit the ripening. The diameter and chirality of the carbon nanotubes were also seen to affect the Ostwald ripening of the catalyst particles. For a collection of carbon nanotubes that contains different diameters and chiralities, the clusters attached to carbon nanotubes with large diameters and strong carbon–metal adhesion are the most likely to survive the Ostwald ripening.

  • 177.
    Börjesson, Anders
    et al.
    University of Borås, School of Engineering.
    Erdtman, Edvin
    University of Borås, School of Engineering.
    Ahlström, Peter
    University of Borås, School of Engineering.
    Berlin, Mikael
    Andersson, Thorbjörn
    Bolton, Kim
    University of Borås, School of Engineering.
    Molecular modelling of oxygen and water permeation in polyethylene2013In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 54, no 12, p. 2988-Article in journal (Refereed)
    Abstract [en]

    Monte Carlo and molecular dynamics simulations were performed to calculate solubility, S, and diffusion, D, coefficients of oxygen and water in polyethylene, and to obtain a molecular-level understanding of the diffusion mechanism. The permeation coefficient, P, was calculated from the product of S and D. The AMBER force field, which yields the correct polymer densities under the conditions studied, was used for the simulations, and it was observed that the results were not sensitive to the inclusion of atomic charges in the force field. The simulated S for oxygen and water are higher and lower than experimental data, respectively. The calculated diffusion coefficients are in good agreement with experimental data. Possible reasons for the discrepancy in the simulated and experimental solubilities, which results in discrepancies in the permeation coefficients, are discussed. The diffusion of both penetrants occurs mainly by large amplitude, infrequent jumps of the molecules through the polymer matrix.

  • 178.
    Börjesson, Anders
    et al.
    University of Borås, School of Engineering.
    Harutyunyan, Avetik R.
    Curtarolo, Stefano
    Bolton, Kim
    University of Borås, School of Engineering.
    Computational study of the thermal behavior of iron clusters on a porous substrate2008In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 77, no 11Article in journal (Refereed)
  • 179.
    Börjesson, Anders
    et al.
    University of Borås, School of Engineering.
    Zhu, Wuming
    Amara, Hakim
    Bichara, Christophe
    Bolton, Kim
    University of Borås, School of Engineering.
    Computational studies of metal-carbon nanotube interfaces for regrowth and electronic transport2009In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 9, no 3, p. 1117-1120Article in journal (Refereed)
    Abstract [en]

    First principles and tight binding Monte Carlo simulations show that junctions between single-walled carbon nanotubes (SWNTs) and nickel clusters are on the cluster surface, and not at subsurface sites, irrespective of the nanotube chirality, temperature, and whether the docking is gentle or forced. Gentle docking helps to preserve the pristine structure of the SWNT at the metal interface, whereas forced docking may partially dissolve the SWNT in the cluster. This is important for SWNT-based electronics and SWNT-seeded regrowth.

  • 180. Calderaro, Luca
    et al.
    Fetter, Alexander L.
    Massignan, Pietro
    Wittek, Peter
    University of Borås, Faculty of Librarianship, Information, Education and IT.
    Vortex dynamics in coherently coupled Bose-Einstein condensates2017In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 95, no 2, article id 023605Article in journal (Other academic)
    Abstract [en]

    In classical hydrodynamics with uniform density, vortices move with the local fluid velocity. This description is rewritten in terms of forces arising from the interaction with other vortices. Two such positive straight vortices experience a repulsive interaction and precess in a positive (anticlockwise) sense around their common centroid. A similar picture applies to vortices in a two-component two-dimensional uniform Bose-Einstein condensate (BEC) coherently coupled through rf Rabi fields. Unlike the classical case, however, the rf Rabi coupling induces an attractive interaction and two such vortices with positive signs now rotate in the negative (clockwise) sense. Pairs of counter-rotating vortices are instead found to translate with uniform velocity perpendicular to the line joining their cores. This picture is extended to a single vortex in a two-component trapped BEC. Although two uniform vortex-free components experience familiar Rabi oscillations of particle-number difference, such behavior is absent for a vortex in one component because of the nonuniform vortex phase. Instead the coherent Rabi coupling induces a periodic vorticity transfer between the two components.

  • 181.
    Camuz, Soner
    et al.
    Chalmers tekniska högskola.
    Bengtsson, Magnus
    University of Borås, Faculty of Textiles, Engineering and Business.
    Söderberg, Rikard
    Chalmers tekniska högskola.
    Reliability based design optimization of surface-to-surface contact for cutting tool interface designs2019In: Journal of manufacturing science and engineering, ISSN 1087-1357, E-ISSN 1528-8935Article in journal (Refereed)
    Abstract [en]

    In recent year, cutting tool manufacturers are moving towards improving the robustness of the positioning of an insert in the tool body interface. Increasing the robustness of the interface involves designs with both chamfered and serrated surfaces. These designs have a tendency to over-determine the positioning and cause instabilities in the interface. Cutting forces generated from the machining process will also plastically deform the interface, consequently, altering the positioning of the insert. Current methodologies within positioning and variation simulation use point-based contacts and assume linear material behaviour. In this article, a first order reliability-based design optimization framework that allows robust positioning of surface-to-surface-based contacts is presented. Results show that the contact variation over the interface can be limited to pre-defined contact zones, consequently allowing successful positioning of inserts in early design phases of cutting tool designs.

  • 182. Candefjord, Stefan
    et al.
    Sandsjö, Leif
    University of Borås, School of Engineering.
    Andersson, Robert
    Carlborg, Niklas
    Szakal, Adam
    Westlund, Johannes
    Sjöqvist, Bengt Arne
    Using Smartphones to Monitor Cycling and Automatically Detect Accidents: Towards eCall Functionality for Cyclists2014Conference paper (Refereed)
    Abstract [en]

    Automatic crash notification to the nearest emergency center in case of a traffic accident will through the EU initiative eCall improve the safety for cars on European roads. eCall functionality could also increase the safety for vulnerable road users such as cyclists, but there is no technical implementation agreed upon for this purpose. We propose to use smartphones due to their widespread availability and no need for extra hardware. Today’s high-end smartphones are equipped with both GPS functionality and movement sensors. The aims of this study were to explore if smartphones can be used to collect cycling data of sufficient quality and to design and evaluate a crash detection algorithm (CDA) for cycling accidents. A Google Nexus 4 smartphone was chosen for the study. This device is equipped with a combined accelerometer and gyroscope chip. Over five hours of “normal” cycling data, i.e. without accidents/incidents, was collected. Six crash tests were performed using a simplified crash test dummy. In order to achieve a realistic user scenario the smartphone was allowed to be easily carried as in everyday use, i.e. the users were not required to fix it to the body. We used the total acceleration based on the sum of square of each direction to obtain a measure independent on smartphone orientation. For normal cycling this measure was found to momentarily be as high as 50 ms2. High levels were often due to handling of the smartphone. This prompted that an acceleration threshold alone is not sufficient for an accurate CDA. A marked rotation during a short time interval was found to be an important predictor for crashes. An accurate CDA was designed based on a combination of sensor data such as acceleration and rotation. The CDA detected all crashes and was subsequently evaluated in several hours of normal cycling without any false positive alarms.

  • 183.
    Carlsson, Johanna
    University of Borås, Faculty of Librarianship, Information, Education and IT.
    Digitala nummerlappar – Lösningen till långa köer2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Waiting in lines is something that most people do not like, especially waiting in long queues where the waiting drags on. In an attempt to reduce the waiting time for customers companies have begun to develop new types of queue management systems which support smartphone based queue tickets. The companies offer the smartphone based queue tickets in different ways, either by SMS or a mobile application. In addition to the usual functionality that traditional queue management systems offers the smartphone-based queue tickets provide users, with the ability to receive updates about the queue, connect to a queue without being physically on the site and inform the system that they left the queue.The purpose of this study was to investigate if smartphone based queue tickets affect the customer satisfaction compared to traditional systems. There was a need for such an investigation because the queue management system that support smartphone based queue tickets are relatively new and no research which examines the affect that smartphone based queue tickets has on customer satisfaction could be found. The question asked was: Does a smartphone based queue ticket application affect the customer satisfaction of the customer compared to a traditional system?The study used an experimental approach to answer the question. A field experiment was conducted in the student office at the University in Borås were the visitors could choose either a mobile application or a paper queue ticket. When the visitors’ had been served they were asked to answer a questionnaire about customer satisfaction. The results from the survey were used to calculate a customer satisfaction scores for each respondent and to compare the responses of the groups with different queue ticket types. The mean of the customer satisfaction scores of each group were also calculated and compared using independent samples t-test.The results of the study showed that the users of mobile application queue tickets were significantly more satisfied than those who used paper queue tickets. The results of the individual questions showed that for some questions the customer satisfaction were positively affected but for other questions the customer satisfaction were not affected. The overall conclusion was that a smartphone based queue ticket application affects the customer satisfaction positively compared to a traditional queue management system.

  • 184.
    Carlsson, Raul
    et al.
    University of Borås, School of Business and IT.
    Hjalmarsson, Anders
    University of Borås, School of Business and IT.
    Lind, Mikael
    University of Borås, School of Business and IT.
    Rudmark, Daniel
    University of Borås, School of Business and IT.
    Challenges when digital services for sustainable everyday travel is innovated2010Conference paper (Other academic)
    Abstract [en]

    In 2020 according to Traffic Authorities, if all car commuters shift from using cars one day a week to use public transport the green-house reduction goals in Western Sweden in relation to transport will be met. A shift from cars to public ways of transport means a step towards the objective eco-effectiveness (Watson et. al. 2010) as commuters actively change their behavior and consume lesser natural resources to achieve the same travel goal. It is also a step towards eco-equity. By using means of commuter transport functions and services with better environmental performance (such as bicycle or public transport systems like bus, tram or train) each commuter consumes less resources which leaves more resources for future generations, and if the systems are well-trimmed it may even be made to balance with nature’s regeneration capability of energy resources. We argue that it is the responsibility of IS researchers to investigate and evaluate how IS/IT may improve the environmental performance of the systems they work with, and in particular if IT/IS may serve as a persuasive force to stimulate shifts towards more eco-friendly alternatives of transportation. For example, we consider it our responsibility to investigate how IS/IT may increase the eco-efficiency of transportation assets when the volume of travelers of shared resources increases as a consequence of such a shift. People should be able to plan their trip in a way suitable for them as individuals while at the same time being supported to choose sustainable alternatives. In practice they should be able to base decisions regarding trips on information about the reliability of transport services and traffic, on the price, and on the environmental performance, provided to them via digital context based information services. In order to succeed in innovation of new digital services for sustainable travel a number of challenges must be prevailed. These challenges can be related to consumers, service and transport suppliers and governmental authorities in the public transport context.

  • 185. Carlsson, Sven
    et al.
    Frygell, Linda
    Hedman, Jonas
    University of Borås, School of Business and IT.
    CRM System Implementation: How Great Expectations in Sweden are Dashed in China2008Conference paper (Other academic)
  • 186. Carlsson, Sven
    et al.
    Hedman, Jonas
    University of Borås, School of Business and IT.
    Steen, Odd
    Model Curriculum for a Bachelor of Science Program in Business Information Systems Design (BISD 2007): Organisational Impacts.2007Conference paper (Refereed)
  • 187. Carlsson, Sven
    et al.
    Hedman, Jonas
    University of Borås, School of Business and IT.
    Steen, Odd
    Model Curriculum for a Bachelor of Science Programme in Business Information Systems Design (BISD 2007)2007In: In proceedings of the 2nd International Conference on Design Science Research in Information Systems and Technology. May 13-15, 2007, The Westin Pasadena, California, USA., 2007Conference paper (Refereed)
  • 188.
    Carney Almroth, Bethanie M.
    et al.
    University of Gothenburg.
    Åström, Linn
    University of Gothenburg.
    Roslund, Sofia
    Petersson, Hanna
    Johansson, Mats
    University of Borås, Faculty of Textiles, Engineering and Business.
    Persson, Nils-Krister
    University of Borås, Faculty of Textiles, Engineering and Business.
    Quantifying shedding of synthetic fibers from textiles; a source ofmicroplastics released into the environment2017In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, article id 10.1007/s11356-017-0528-7Article in journal (Refereed)
    Abstract [en]

    Microplastics in the environment are a subject of intense research as they pose a potential threat to marine organisms. Plastic fibers from textiles have been indicated as a major source of this type of contaminant, entering the oceans via wastewater and diverse non-point sources. Their presence is also documented in terrestrial samples. In this study, the amount of microfibers shedding from synthetic textiles was measured for three materials (acrylic, nylon, polyester), knit using different gauges and techniques. All textiles were found to shed, but polyester fleece fabrics shed the greatest amounts, averaging 7360 fibers/m−2/L−1 in one wash, compared with polyester fabrics which shed 87 fibers/m−2/L−1. We found that loose textile constructions shed more, as did worn fabrics, and high twist yarns are to be preferred for shed reduction. Since fiber from clothing is a potentially important source of microplastics, we suggest that smarter textile construction, prewashing and vacuum exhaustion at production sites, and use of more efficient filters in household washing machines could help mitigate this problem.

  • 189. Chalapati, Sachin
    et al.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Toluene mediated fluid catalytic cracking of low density polyethylene using ionic liquids2014Conference paper (Other academic)
  • 190. Chelakara Satyanarayana, Kavitha
    et al.
    Bohlén, Martin
    University of Borås, School of Engineering.
    Lund, Anja
    Rychwalski, Rodney
    Bolton, Kim
    University of Borås, School of Engineering.
    Analysis of the torsion angle distribution of poly(vinylidene fluoride) in the melt2012In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 53, no 4, p. 1109-1114Article in journal (Refereed)
    Abstract [en]

    Analysis of the torsionangledistribution of poly(vinylidene fluoride) (PVDF) structures at temperatures above its melting point is addressed by combining first principles methods, atomistic simulations and laboratory experiments. Amorphous, α- and β-conformations of PVDF structures have been considered. The results from the atomistic simulations as well as the experiments show that there is a larger probability of the PVDF torsions to be near ±180° at temperatures above the melting point, which is associated more with the β-conformation than the α-conformation.

  • 191. Chelakara Satyanarayana, Kavitha
    et al.
    Bolton, Kim
    University of Borås, School of Engineering.
    Molecular dynamics simulations of α- to β-poly (vinylidene fluoride) phase change by stretching and poling2012In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 53, no 14, p. 2927-2934Article in journal (Refereed)
    Abstract [en]

    The mechanism of inducing a phase change from α-poly(vinylidene fluoride) (α-PVDF) to β-PVDF is addressed using molecular dynamics simulations based on a molecular mechanics force field. The effect of applying a strain to the α-PVDF crystal along the axis of the molecules is investigated, as well as poling the crystal before or after stretching. Rather large (at least 1010 V/m) electric fields that are perpendicular to the axis of the PVDF molecules are required to induce α- to β-PVDF phase change when no strain is applied to the α-PVDF crystal. However, at a strain of 1.0475 (i.e., when the crystal is stretched by 4.75%) α-PVDF changes to a β-PVDF like structure, where the β-PVDF molecules orientate anti-parallel relative to each other. Transformation of the anti-parallel β-PVDF to β-PVDF can be induced by poling (even at the lowest electric field of 105 V/m studied here) or by thermal annealing.

  • 192.
    Chen, Wei
    et al.
    Fudan University.
    Augusto, Juan CarlosMiddlesex University.Seoane, FernandoUniversity of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.Ledhocki, FedorSlovak University of Technology.Arends, JohanTechnical University of Technology.Ungureanu, ConstantinHobo Heeze.Wichert, ReinerFraunhofer IGD.
    Recent Advances in Ambient Assisted Living: Bridging Assistive Technologies, e-Health and Personalized Health Care2015Collection (editor) (Refereed)
  • 193.
    Cho, Sung-Woo
    University of Borås, School of Engineering.
    Aging and Heat-Sealing Properties of Films based on Wheat Gluten2007Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Recently the research interest of the possibility of using wheat gluten (WG) as packaging material has greatly increased due to its combination of high gas barrier, attractive mechanical, film-forming and renewable properties. The source is also readily available and inexpensive on a worldwide basis. The glycerol-plasticized WG films cast from pH 4 and pH 11 solutions were investigated in order to understand the mechanisms behind the undesired aging. The film prepared from the pH 11 solution was mechanically more stable upon aging than the pH 4 film, which was initially very ductile but turning brittle with time. It was revealed that the protein structure of the pH 4 film was initially less polymerized/aggregated and the polymerization increased during storage but it did not reach the degree of aggregation of the pH 11 film, whereas deamidation was occurred and increased in the pH 11 film. During aging, the pH 4 film lost more mass than the pH 11 film mainly due to migration of glycerol but also due to some loss of volatile mass and the greater plasticizer loss of pH 4 film was presumably due to its initial lower degree of protein aggregation /polymerization. The glycerol migration of cast films exposed to a porous paper was further investigated with respect to pH of cast solution, glycerol content and film thickness since it was the main reason for deterioration of the properties. The opacity was also characterized. The glycerol migration was quantified using GC method in order to determine only glycerol content, but not other volatile substances. Glycerol content did not significantly change the opacity and pH 4 films showed good contact clarity because of less Maillard reaction. Glycerol was extensively migrating to the paper support and the migration seemed to be diffusion controlled. The heat sealability of WG films was investigated, using an impulse-hear sealer. It was observed that the WG films were readily sealable keeping up their integrity. The sealing temperature had a negligible effect on the lap-shear strength, but the peel strength increased with sealing temperature. The lap-shear strength increased with increasing mold temperature and the failure mode changed.

  • 194.
    Cho, Sung-Woo
    University of Borås, School of Engineering.
    Protein-based packaging films, sheets and composites: process development and functional properties2009Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The depletion of the petroleum resources and a number of environmental concerns led to considerable research efforts in the field of biodegradable materials over the last few decades. Of the diverse range of biopolymers, wheat gluten (WG) stands out as an alternative to synthetic plastics in packaging applications due to its attractive combination of flexibility and strength, high gas barrier properties under low humidity conditions and renewability. The availability of raw materials has also been largely increased with an increase in the production of WG as a low-cost surplus material due to increasing demand for ethanol as fuel. In this study, WG was processed into films, sheets and composites using some of the most widely used techniques including solution casting, compression molding, extrusion and injection molding, accompanying process optimizations and characterization of their functional properties. This thesis consists mainly of six parts based on the purpose of the study. The first part addresses the aging and optical properties of the cast film in order to understand the mechanisms and reasons for the time-dependant physical and chemical changes. The films plasticized with glycerol were cast from acidic (pH 4) and basic (pH11) solutions. The film prepared from the pH 11 solution was mechanically more stable upon aging than the pH 4 film, which was initially very ductile but became brittle with time. It was revealed that the protein structure of the pH 4 film was initially less polymerized/aggregated and the polymerization increased during storage but it did not reach the degree of aggregation of the pH 11 film. During aging, the pH 4 film lost more mass than the pH 11 film mainly due to migration of glycerol but also due to some loss of volatile mass. In addition the greater plasticizer loss of the pH 4 film was presumably due to its initial lower degree of protein aggregation/polymerization. Glycerol content did not significantly change the opacity and pH 4 films showed good contact clarity because of less Maillard reaction. In the second part, the heat-sealability of WG films was investigated, using an impulse-heat sealer, as the sealability is one of the most important properties in the use of flexible packaging materials. It was observed that the WG films were readily sealable while preserving their mechanical integrity. The sealing temperature had a negligible effect on the lap-shear strength, but the peel strength increased with sealing temperature. The lap-shear strength increased with increasing mold temperature and the failure mode changed. The third part describes the possibility of using industrial hemp fibers to reinforce wheat gluten sheets based on evaluation of the fiber contents, fiber distribution and bonding between the fibers and matrix. It was found that the hemp fibers enhanced the mechanical properties, in which the fiber contents played a significant role in the strength. The fiber bonding was improved by addition of diamine as a cross-linker, while the fiber distribution needed to be improved. The fourth part presents a novel approach to improve the barrier and mechanical properties of extruded WG sheets with a single screw extruder at alkaline conditions using 3-5wt.% NaOH with or without 1 wt.% salicylic acid. The oxygen barrier, at dry conditions, was improved significantly with the addition of NaOH, while the addition of salicylic acid yielded poorer barrier properties. It was also observed that the WG sheets with 3 wt.% NaOH had the most suitable combination of low oxygen permeability and relatively small time-dependant changes in mechanical properties, probably due to low plasticizer migration and an optimal protein aggregation/polymerization. In the fifth part WG/PLA laminates were characterized for the purpose of improving the water barrier properties. The lamination was performed at 110°C and scanning electron microscopy showed that the laminated films were uniform in thickness. The laminates significantly suppressed the mass loss and showed promising water vapor barrier properties in humid conditions indicating possible applications in packaging. The final part addresses the development of injection molding processes for WG. Injection-molded nanocomposites of WG/MMT were also characterized. WG sheets were successively processed using injection molding and the process temperatures were found to preferably be in a range of 170-200°C, which was varied depending on the sample compositions. The clay was found to enhance the processability, being well dispersed in the matrix. The natural clay increased the tensile stiffness, whereas the modified clay increased the surface hydrophobicity. Both clays decreased the Tg and increased the thermal stability of the nanocomposites. The overall conclusion was that injection molding is a promising method for producing WG items of simple shapes. Further studies will reveal if gluten can also be used for making more complex shapes.

  • 195.
    Cho, Sung-Woo
    et al.
    University of Borås, School of Engineering.
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mechanical properties of renewable thermoset composites reinforced with natural fibers2010Conference paper (Other academic)
    Abstract [en]

    The focus in this presentation has been to evaluate whether natural fibers can be used as reinforcement in composites based on renewable thermoset resin. Thermoset resins made from renewable resources as alternatives to crude oils are a relatively unexplored and important research area and could be used for a broad range of applications including coatings, inks, adhesives and composites. The common raw materials used in the preparation of biobased thermoset resins are vegetable oils such as soybean oil, rapeseed oil and linseed oil, which are low cost and abundant. Natural fibers as reinforcement have many advantages compared to synthetic fibers, for instance they are biodegradable, low weight and cost, nontoxic and recyclable. In the previous study, a novel thermoset resin [methacrylic anhydride modified soybean oil (MMSO)] was synthesized through the reaction of epoxidized soybean oil with methacrylic acid and used here as matrices. The studied composites based on the neat MMSO resin and the reisn blended with 30 wt.% styrene reinforced with non-woven flax fiber and woven flax fiber mats in different orientations [0°(warp direction), 45°, 90°(weft direction)] were manufactured using compression molding technique. The glass fiber reinforced composite was also prepared for the comparison purpose. The results show that it was possible to produce composite with high mechanical properties when the load is especially applied along the fiber direction, which implies that the structural composites having several plies of natural fiber mats in different orientations could be interesting candidates for use in technical applications.

  • 196.
    Cho, Sung-Woo
    et al.
    University of Borås, School of Engineering.
    Gällstedt, Mikael
    Hedenqvist, Mikael S.
    Effects of glycerol content and film thickness on the properties of vital wheat gluten films cast at pH 4 and 112010In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 117, no 6, p. 3506-3514Article in journal (Refereed)
    Abstract [en]

    This study deals with the optical properties and plasticizer migration properties of vital wheat gluten (WG) films cast at pH 4 and 11. The films contained initially 8, 16, and 25 wt.% glycerol and were aged at 23 °C and 50% relative humidity for at least 17 weeks on a paper support to simulate a situation where a paper packaging is laminated with an oxygen barrier film of WG. The films, having target thicknesses of 50 and 250 μm, were characterized visually and with ultraviolet/visible and infrared spectroscopy; the mass loss was measured by gravimetry or by a glycerol-specific gas chromatography method. The thin films produced at pH 4 were, in general, more heterogeneous than those produced at pH 11. The thin pH 4 films consisted of transparent regions surrounding beige glycerol-rich regions, the former probably rich in gliadin and the latter rich in glutenin. This, together with less Maillard browning, meant that the thin pH 4 films, in contrast to the more homogeneous (beige) thin pH 11 films, showed good contact clarity. The variations in glycerol content did not significantly change the optical properties of the films. All the films showed a significant loss of glycerol to the paper support but, after almost 9 months, the thick pH 11 film containing initially 25 wt.% glycerol was still very flexible and, despite a better contact to the paper, had a higher residual glycerol content than the pH 4 film, which was also more brittle.

  • 197.
    Cho, Sung-Woo
    et al.
    University of Borås, School of Engineering.
    Gällstedt, Mikael
    Hedenqvist, Mikael S.
    Properties of Wheat Gluten/Poly(lactic acid) Laminates2010In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 58, no 12, p. 7344-7350Article in journal (Refereed)
    Abstract [en]

    Laminates of compression-molded glycerol-plasticized wheat gluten (WG) films surrounded and supported by poly(lactic acid) (PLA) films have been produced and characterized. The objective was to obtain a fully renewable high gas barrier film with sufficient mechanical integrity to function in, for example, extrusioncoating paper/board applications. It was shown that the lamination made it possible to make films with a broad range of glycerol contents (0-30 wt.%) with greater strength than single unsupported WG films. The low plasticizer contents yielded laminates with very good oxygen barrier properties. In addition, whereas the unsupported WG films had an immeasurably high water vapor transmission rate (WVTR), the laminate showed values that were finite and surprisingly, in several cases, also lower than that of PLA. Besides being a mechanical support (as evidenced by bending and tensile data) and a shield between the WG and surrounding moisture, the PLA layer also prevented the loss of the glycerol plasticizer from the WG layer. This was observed after the laminate had been aged on an “absorbing” blotting paper for up to 17 weeks. The interlayer adhesion (peel strength) decreased with decreasing glycerol content and increasing WG film molding temperature (130 °C instead of 110 °C). The latter effect was probably due to a higher protein aggregation, as revealed by infrared spectroscopy. The lamination temperature (110-140 °C) did not, however, have a major effect on the final peel strength.

  • 198.
    Cho, Sung-Woo
    et al.
    University of Borås, School of Engineering.
    Gällstedt, Mikael
    Johansson, Eva
    Hedenqvist, Mikael S.
    Injection-molded nanocomposites and materials based on wheat gluten2011In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 48, no 1, p. 146-152Article in journal (Refereed)
    Abstract [en]

    This is, to our knowledge, the first study of the injection molding of materials where wheat gluten (WG) is the main component. In addition to a plasticizer (glycerol), 5 wt.% natural montmorillonite clay was added. X-ray indicated intercalated clay and transmission electron microscopy indicated locally good clay platelet dispersion. Prior to feeding into the injection molder, the material was first compression molded into plates and pelletized. The filling of the circular mold via the central gate was characterized by a divergent flow yielding, in general, a stronger and stiffer material in the circumferential direction. It was observed that 20–30 wt.% glycerol yielded the best combination of processability and mechanical properties. The clay yielded improved processability, plate homogeneity and tensile stiffness. IR spectroscopy and protein solubility indicated that the injection molding process yielded a highly aggregated structure. The overall conclusion was that injection molding is a very promising method for producing WG objects.

  • 199.
    Cho, Sung-Woo
    et al.
    University of Borås, School of Engineering.
    Gällstedt, Mikael
    Ullsten, Henrik
    Wretfors, Christer
    Johansson, Eva
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Hedenqvist, Mikael S.
    Protein-based bioplastics and nanocomposites from a processing perspective2010Conference paper (Other academic)
  • 200.
    Cho, Sung-Woo
    et al.
    University of Borås, School of Engineering.
    Persson, Maria
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Melt spun fibres of poly(lactic acid) and hydroxyapatite nanoparticles for use as tissue engineering scaffolds2011Conference paper (Refereed)
1234567 151 - 200 of 1065
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