Gas-filled, flat plate solar collectors

This work treats the thermal and mechanical performances of gas-filled, flat plate solar collectors in order to achieve a better performance than that of air filled collectors. The gases examined are argon, krypton and xenon which all have lower thermal conductivity than air. The absorber is formed as a tray connected to the glass. The pressure of the gas inside is near to the ambient and since the gas volume will vary as the temperature changes, there are potential risks for fatigue in the material. One heat transfer model and one mechanical model were built. The mechanical model gave stresses and information on the movements. The factors of safety were calculated from the stresses, and the movements were used as input for the heat transfer model where the thermal performance was calculated. It is shown that gas-filled, flat plate solar collectors can be designed to achieve good thermal performance at a competitive cost. The best yield is achieved with a xenon gas filling together with a normal thick absorber, where normal thick means a 0.25 mm copper absorber. However, a great deal of energy is needed to produce the xenon gas, and if this aspect is taken into account, the krypton filling is better. Good thermal performance can also be achieved using less material; a collector with a 0.1 mm thick copper absorber and the third best gas, which is argon, still gives a better operating performance than a common, commercially produced, air filled collector with a 0.25 mm absorber. When manufacturing gas-filled flat plate solar collectors, one way of decreasing the total material costs significantly, is by changing absorber material from copper to aluminium. Best yield per monetary outlay is given by a thin (0.3 mm) alu-minium absorber with an argon filling. A high factor of safety is achieved with thin absorbers, large absorber areas, rectangular constructions with long tubes and short distances between glass and absorber. The latter will also give a thin layer of gas which gives good thermal performance. The only doubtii ful construction is an argon filled collector with a normal thick (> 0.50 mm) aluminium absorber. In general, an assessment of the stresses for the proposed construction together with appropriate tests are recommended before manufacturing, since it is hard to predict the factor of safety; if one part is reinforced, some other parts can experience more stress and the factor of safety actually drops.

Movies, Mind and Meaning : Studying Audience and Favourite Films

Construction of identity and meaning is becoming increasingly important in both media studies and religion scholarship. (Lövheim, 2004) Meaning construction outside traditional religion has become more interesting for religious studies and what individuals in the audience do with all messages circulated through media in everyday life has attended increasing interest within media studies (Stout and Buddenbaum, 2001). Motion pictures, soap operas and advertising are all examples of media contents which generate ideas among its audience which to a various degree are used as resources within the construction of identity (Jansson, 2001). The investigation of what modern humankind’s world views look like and what components they are composed of, in this context seems to be an important topic of investigation (Holm and Björkqvist, 1996). The ways in which the development of media has effected the daily lives of individuals is interest as is the nature of the self and the ways in which the process of self-formation is affected by the profusion of mediated materials (Thompson, 1995). Film and religion are my interest within this larger frame. The topic is not exactly new but the combination of film and religion has during the last ten years resulted in a rapidly growing number of books by scholars interested in this field (Lyden, 2003). One growing focus is on the role that films can and do play within the emerging and developing valuesystem of people in the West today (Marsh, 2004). The British theologian Clive Marsh’s point of departure is very similar to my own. Viewers bring to a film life-experience, immediate concerns and worldviews and the exploration of this interplay between movies and the interpreting process of meaning making is the very focus in this paper. Theoretically, the semeiological model of Alf Linderman is combined with cultural cognitive approaches used by a number of Scandinavian media scholars developing perspectives in audience theory (Linderman, 1996, Höijer and Werner, 1998). 13 individuals, their favourite movie and what it means to them in their life My aim is to examine how individuals comprehend film and what the meaning process look like. In this paper I present the outcome of 13 interviews with young people about their favourite film. I suggest how it is possible to interpret how they interrelate film comprehension with their personal beliefs and their culturally constructed worldview from a sociocognitive point of view. Examples of films chosen range from Disneys Lion King (1994), sciencefiction and fantasy successes like The Matrix (1999) and Lord of the Rings (2001) or the next best movie ever according to www.IMdb.com The Shawshank Redemption (1994) as well as the Swedish blockbuster Så som i himmelen (2004), aka “As in Heaven”.