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- Bläckberg, Lisa, 1982-
(författare)
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Surface coatings as xenon diffusion barriers on plastic scintillators : Improving Nuclear-Test-Ban Treaty verification
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis investigates the ability of transparent surface coatings to reduce xenon diffusion into plastic scintillators. The motivation for the work is improved radioxenon monitoring equipment, used with in the framework of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty. A large part of the equipment used in this context incorporates plastic scintillators which are in direct contact with the radioactive gas to be detected. One problem with such setup is that radioxenon diffuses into the plastic scintillator material during the measurement, resulting in an unwanted memory effect consisting of residual activity left in the detector. In this work coatings of Al2O3 and SiO2, with thicknesses between 20 and 400 nm have been deposited onto flat plastic scintillator samples, and tested with respect to their Xe diffusion barrier capabilities. All tested coatings were found to reduce the memory effect, and 425 nm of Al2O3 showed the most promise. This coating was deposited onto a complete detector. Compared to uncoated detectors, the coated one presented a memory effect reduction of a factor of 1000. Simulations and measurements of the expected light collection efficiency of a coated detector were also performed, since it is important that this property is not degraded by the coating. It was shown that a smooth coating, with a similar refractive index as the one of the plastic, should not significantly affect the light collection and resolution. The resolution of the complete coated detector was also measured, showing a resolution comparable to uncoated detectors. The work conducted in this thesis proved that this coating approach is a viable solution to the memory effect problem, given that the results are reproducible, and that the quality of the coating is maintained over time.
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| 3. |
- Rehal, Saddek, 1950
(författare)
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Att artikulera och kommunicera insikt - bild och ord i tidiga skeden av designprocesser
- 1997
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the development of a method and tool for communication between participants in the early stages of a design process. Such methods are part of what we call collective design processes. This term implies stronger user influence than normally is the case in participatory design. A collective design process is an activity where actors from different disciplines in an organisation, as well as external experts, take part in the actual design process. In traditional participatory design processes the architect leads the process. He listens to the users and interprets what they say when looking for solutions.A major problem in all participatory design processes is communication. The individual, social, professional and cultural differences within an organisation are often a barrier for communication. One kind of problem is the difficulties which arise when the actors from different disciplines use different languages to communicate with each other. The actors interpret the information they receive according to their own language, related to their professional, cultural and social situation.Another problem is the communication between the designer and the participants from a client organisation. The designer has the ability to communicate by means of pictures and sketches, while the other actors use common language. This situation gives the designer a big advantage. The designer has the opportunity to set the agenda for the discussion. Graphic representations produced by the designer can also influence the thinking of the other actors, especially if they have not yet articulated their own concepts.The method and tool we have developed are useful for communication between the designer and the other actors, as well as cross-disciplinary communication within the organisation. We propose to use pictures in early stages of the collective design process to give the actors an opportunity to reflect and articulate pre-conceptual ideas first for themselves, then for each other in order to develop a common understanding. By doing so the actors develop a language game related to the specific situation. The understanding will then be easier to communicate further to the designer.In this thesis I describe the design of a suggested method for articulation and communication in early stages of the design process.
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| 4. |
- Tepfers, Ralejs, 1933
(författare)
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Betona tehnoloģija - porainība ir izšķiroša
- 2011
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Ingår i: Philosophy and Foundations of Physics. - 1871-1774. - 9789934102271 ; -:Tezu Krajums Sekcija: Tehniskas zinatnes., s. 38-42
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Konferensbidrag (refereegranskat)abstract
- Concrete technology – porosity is decisiveBy RALEJS TEPFERSPorosity is the number of pores in a material for instance pores in certain concrete. Porosity is usually expelled in volume percent. The porosity of concrete has influence on the properties in many aspects. Composition of concrete, casting in practice, maturing and hardening, cement reactions and risks at freezing, all are influenced by porosity. The possibilities to influence the type of porosity are important.
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| 5. |
- Zamaratskaia, Galia
(författare)
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Regulation of porcine hepatic cytochrome P450 : implication for boar taint
- 2014
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Ingår i: Computational and Structural Biotechnology Journal. - : Elsevier BV. - 2001-0370. ; 11, s. 106-112
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Forskningsöversikt (refereegranskat)abstract
- Cytochrome P450 (CYP450) is the major family of enzymes involved in the metabolism of several xenobiotic and endogenous compounds. Among substrates for CYP450 is the tryptophan metabolite skatole (3-methylindole), one of the major contributors to the off-odour associated with boar-tainted meat. The accumulation of skatole in pigs is highly dependent on the hepatic clearance by CYP450s. In recent years, the porcine CYP450 has attracted attention both in relation to meat quality and as a potential model for human CYP450. The molecular regulation of CYP450 mRNA expression is controlled by several nuclear receptors and transcription factors that are targets for numerous endogenously and exogenously produced agonists and antagonists. Moreover, CYP450 expression and activity are affected by factors such as age, gender and feeding. The regulation of porcine CYP450 has been suggested to have more similarities with human CYP450 than other animal models, including rodents. This article reviews the available data on porcine hepatic CYP450s and its implications for boar taint.
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