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  • Presentation: 2019-02-28 10:00 Rånbyrummet, Stockholm
    Huang, Tianxiao
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Betulin-modified cellulosic textile fibers with improved water repellency, hydrophobicity and antibacterial properties2019Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Textiles made from natural sources, such as cotton and flax, have advantages over those made of synthetic fibers in terms of sustainability. Unlike major synthetic fibers that have a negative impact on the environment due to poor biodegradability, cotton cellulose is a renewable material.Cotton cellulose fibers exhibit various attractive characteristics such as softness and inexpensiveness. Cellulosic textiles can be easily wetted, since the structure contains a large amount of hydrophilic hydroxyl groups, and when water repellency is needed, this is a disadvantage. Currently, paraffin waxes or fluorinated silanes are used to achieve hydrophobicity, but this contradicts the concept of green chemistry since these chemicals are not biodegradable. The use of bio-based materials like forest residues or side-streams from forest product industries might be a good alternative, since this not only decreases the pressure on the environment but can also increase the value of these renewable resources.Betulin is a hydrophobic extractive present in the outer bark of birch trees (Betula verrucosa). Nowadays, the birch bark containing betulin generated in the paper industry is disposed of by incineration as a solid fuel to provide energy, but this application is not highly valuable and this motivates us to see whether betulin can be used as a hydrophobe to prepare waterproof cellulosic textiles. Methods of dip-coating, film compression molding and grafting were performed to build “betulin-cellulosic textile system” to render the textile with hydrophobicity and other functions. The textile impregnated in a solution of betulin-based copolymer exhibited a contact angle of 151°, which indicated that superhydrophobicity can be reached. AATCC water spray test results showed that cellulosic textile coated with betulin-based film had a water repellency of 80, which is the third highest class according to the rating standards. Betulin-grafted textiles were also prepared and showed a static water contact angle of 136°, and an antibacterial property with a bacterial removal of 99%.This thesis proposes that betulin can be used as a green alternative in functional material preparation. By developing betulin, a more value-added application rather than incineration can be achieved.

    Fulltekst tilgjengelig fra 2019-03-01 13:20
  • Presentation: 2019-03-06 13:00 1440, Stockholm
    Koller, Marius
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Supporting Patients and Therapists in Virtual Reality Exposure Therapy2019Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

     This thesis explores challenges for the design of Virtual Reality Exposure Therapy (VRET) systems. Exposure therapy is the established method for treatment of anxiety disorders and is typically delivered in-vivo, i.e. exposure to phobic stimulus in real environments. Virtual reality (VR), instead, offers the potential to conduct exposure therapy at the clinic. This approach has several benefits in terms of efficiency, customization and control, amount of exposure, and as an transition phase to real situations. However, currently many systems are limited in scope and are designed for research purposes without informing the design from therapist's practices. 

    My research aims to contribute towards the understanding of current practices in exposure therapy and investigates challenges for the design of these systems for the two main user groups, patients and therapists. Three different focus areas have been prevalent. First, we have studied therapist in real sessions to inform the design and development of VRET-systems. Second, we have evaluated two different VRET implementations supporting therapists to interact with patients. Third, on the patient's side, we have studied presence on healthy participants focusing on the influence of virtual bodies and patient movement in VR.

    This thesis summarises and discusses these studies. Overall, the studies emphasize the complexity of exposure therapy and the need for individualized patient conditions. This poses multiple challenges for the design of VRET-systems such as, first, the systems must offer flexibility to the therapists to orchestrate individualized therapy. Second, the systems must enable rich therapists-patient interaction. Third, the complexity of individualization of scenarios and sessions must be addressed in the design of the therapist's interface. Fourth, for patients, body avatars influences presence differently depending on the scenario and locomotion is challenging as offices are typically small.

  • Presentation: 2019-03-12 13:00 Stockholm
    Sörenson, Karl
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Filosofi och historia.
    In Search of Lost Deterrence – Two essays on deterrence and the models employed to study the phenomenon2019Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    To deter is central for strategic thinking. Some of the more astute observations regarding the dynamics of deterrence were made during the Cold War by game theorists. This set the stage for how deterrence has come to be studied. A strong methodological element like the research on deterrence’s reliance on game theory requires examination in order to understand what sort of knowledge it actually yields. What sort of knowledge does one acquire when deterrence is viewed through game theoretic models? How do they inform us about the phenomenon of deterrence? To understand the nature of a phenomenon through models requires idealization, which in turn presupposes assumptions. This licentiate thesis investigates the type of knowledge we attain when approaching deterrence from a game theoretic perspective. The two articles presented address two separate but related issues. The first article reviews a debate regarding which deterrence model best capture the phenomena of deterrence, i.e. how models can be compared to one and other. The article presents a framework for comparing models and then appraises how these different deterrence models inform us about deterrence. The second article uses one of the more central deterrence models in order to evaluate how and to what extent the naval operation Atalanta managed to deter the Somali piracy.

  • Presentation: 2019-04-03 13:00 E2, Stockholm
    Francart, Nicolas
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Buildings in municipal climate change mitigation strategies: towards life cycle thinking2019Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Fulfilling climate targets requires ambitious changes. The building sector is a large contributor to emissions of greenhouse gases (GHG), but also offers opportunities for climate change impact reductions. This thesis aims at supporting strategic decisions to reach climate change mitigation targets in the building sector, based on knowledge about what factors contribute significantly to climate impact from buildings in a life cycle perspective and how practitioners can influence these factors. More specifically, a first point of investigation concerns what aspects play a key importance in buildings’ climate impact, and what climate change mitigation strategies for the building sector should focus on. A quantitative analysis of backcasting scenarios for 2050 was performed using a spreadsheet model to estimate GHG emissions for the building sector. The parameters were adjusted to ensure that a GHG emission quota was reached in every scenario. This provided an illustration of four very different ways the building sector could contribute to the fulfillment of a global climate change mitigation target. The results were used to discuss what aspects of buildings were particularly important for target fulfillment. These aspects include a low-carbon energy mix, a reduction of GHG emissions from construction materials and an optimized use of space. A second point of investigation concerns how municipalities can influence practices through the use of environmental requirements in construction, in particular requirements based on a life cycle approach. A survey of Swedish municipalities was used to assess their current practices and knowledge level regarding mitigating climate change impact from construction, as well as the influence of a municipality’s size on these practices. It was followed up by semi-structured interviews investigating barriers to the use of environmental requirements in construction. Barriers were identified regarding in-house skills, access to data, resources, ambiguities regarding the law and guidance from national authorities. A stepwise strategy was suggested to overcome these barriers and successfully implement environmental requirements. Therefore, the thesis as a whole provides insight on how municipalities could use environmental requirements in construction to influence current practices in the building sector, so that the changes needed to fulfill the 1.5℃ target are implemented.