The design of an active-unity power factor correction circuit with variable-hysteresis control for off-line dc-to-dc switching power supplies is described. Design equations relating the boost inductor current ripple to the circuit components selection and circuit performance arc discussed. A computer-aided design program (CADO) is developed to give the optimal circuit components selection. A 500 watt, 300 volt experimental circuit is built to verify the simulation and analysis results. The control-to-output response of the power factor circuit is verified with the experimental results. Design guidelines for the low-frequency feedback network are presented. Small-signal closed-loop responses are measured with an experimental power factor circuit. / Master of Science

No description available.

No description available.

The current paper presents a study conducted at At-Bristol Science Centre, UK. It is a front-end evaluation for the “Live Science Zone” at At-Bristol, which will be built during the autumn of 2004. It will provide a facility for programmed events and shows, non-programmed investigative activities and the choice of passive or active exploration of current scientific topics. The main aim of the study is to determine characteristics of what kind of techniques to use in the Live Science Zone. The objectives are to explore what has already been done at At-Bristol, and what has been done at other science centres, and to identify successful devices. The secondary aim is mapping what sorts of topics that visitors are actually interested in debating. The methods used in the study are deep qualitative interviews with professionals working within the field of science communication in Europe and North America, and questionnaires answered by visitors to At-Bristol. The results show that there are some gaps between the intentions of the professionals and the opinions of the visitors, in terms of opportunities and willingness for dialogue in science centre activities. The most popular issue was Future and the most popular device was Film.

Autismspektrumtillstånd kännetecknas av kärnsymtomen stereotypa, repetitiva beteenden samt nedsatt förmåga att kunna hantera sociala relationer. Diagnostisering försvåras dock av att inga biomarkörer finns tillgängliga än. Forskning pågår för att få klarhet i patofysiologiska mekanismer, där funna defekta gener ger en bild av ökade svårigheter för nervcellen att reglera signaler efter behov. Behandling som riktar sig mot kärnsymtomen vid autismspektrumtillstånd finns ej, men forskning pågår för att hitta lämpliga läkemedel. Syftet med detta arbete var att sammanställa senaste forskningen inom detta område, via sökning efter dubbelblinda randomiserade kontrollerade studier, för att utvärdera om något läkemedel kommer finnas på marknaden inom en snar framtid. Studier med D-vitamin, bumetanid (diuretikum), suramin (antipurinergt), memantin ”extended release” (mot Alzheimers sjukdom), metylerad vitamin B12 och celecoxib (anti-inflammatoriskt) som adjuvans till risperidon (neuroleptikum) utvärderades för effekten på kärnsymtom vid autismspektrumtillstånd. Bumetanid, som är ett loop-diuretikum, var det läkemedel som kommit längre än övriga. Om även fas 3 ger positiva resultat så finns möjligheten att detta kan släppas på europeiska marknaden om några år för behandling av kärnsymtom vid autismspektrumtillstånd. Övriga substanser var i ett mycket tidigt utvecklingsstadium. / Autism spectrum disorder is characterised by the core symptoms stereotypic, repetitive behaviors and impaired ability to handle social relationships. Diagnostics, however, is complicated by the fact that no biomarkers are available yet, i.e. one cannot take a blood test to decide if the individual can be diagnosed with autism spectrum disorder. Research, however, is ongoing in this field hopefully also leading to markers that can be used when evaluating degree of severity during clinical research where potential pharmaceuticals are evaluated in humans. Research is ongoing to clarify pathophysiological mechanisms. Identified clusters of defective genes suggest increased difficulties of nerve cells to regulate signals as needed. For example, excitation or inhibition of nerve cells can be enhanced. Treatment aimed at the core symptoms of autism spectrum disorder is not available, but research is ongoing to find suitable drugs. The purpose of this work was to compile the latest research in this area through a search for doubleblinded randomized controlled studies to evaluate whether any drug will be available on the market in the near future. Studies with vitamin D, bumetanide (diuretic), suramin (antipurinergic), memantine “extended release” formulation (Alzheimer’s disease drug), methylated vitamin B12 and celecoxib (anti-inflammatory) as adjuvant to risperidone (neuroleptic) were evaluated for the effect on core symptoms in autism spectrum disorder. Bumetanide, which is a loop-diuretic, is the drug that has come further than the rest. If the continued development of this drug also gives positive results, there is the possibility that this drug can be released on the European market in a few years, for treatment of core symtoms. The other substances evaluated were at a very early stage of development. Some of these, however, can be of extra interest. For example D‑vitamin which can have some potential effect. Also it gives minimal side effects.

Nature brings lot of possibilities and inspirational ideas in various industries. Many fields of human activity from transportation, energy and electronics derives inspiration from natural structures and systems to be more efficient. The civil engineering and industry of building materials is not an exception. The ongoing joint research project CRC/TRR 280 [1] aimed on looking for a new methodology and approaches in design of light weight and bio inspired structures made of textile reinforced concrete (TRC). Special interest is on shell structures with membrane stresses that brings an extremely favourable span-to-material ratio that in turn means excellent structural performance. The current paper aimed to show the numerical side of the current research project.