Utveckling och prov av en 50 kJ elektrisk pulsgenerator

Detta arbete beskriver en elektrisk pulsgenerator, dess konstruktion och ingående komponenter.Särskild uppmärksamhet ägnas åt det triggade gnistgapet och triggpulsgeneratorn. Gnistgapetskonstruktion beskrivs. En SPICE-modell utvecklas för gnistgapets urladdningskanal.Urladdningskanalens egenskaper simuleras. Simulerad och fotograferad kanalradie jämförs.Några genomförda försök beskrivs kort, däribland det katastrofala och avslutande försöket. Detavslutande försöket analyseras. Avslutningsvis avhandlas några tänkbara utbyggnader ochförbättringar.

Vad ska elever lära sig angående naturvetenskaplig verksamhet? : En analys av svenska läroplaner för grundskolan under 50 år

The purpose of this study is to contribute to an understanding of which changes related to scientific inquiry have been made historically in curriculum documents. A comparative analysis is made of five Swedish national curricula– Lgr 62, Lgr 69, Lgr 80, Lpo 94 and Lgr 11 – during the last 50 years regarding what compulsory school students (school years 1–9) should learn about scientific inquiry. It focuses 1) what students should learn about carrying out scientific inquiries, and 2) what students should learn about the nature of science. All of the curricula examined have aims concerning scientific inquiry. The results show that during the period there have been many shifts in emphasis and changes of aims, for example from learning an inductive method to a more deductive one, and from an emphasis on carrying out investigations to an emphasis on more conceptual understanding of scientific investigations. Because teaching traditions tend to conserve aspects of earlier curricula, it is discussed how the results can help teachers, teacher students and curriculum developers to better see the consequences of the changes for teaching and learning.

Sociologförbundet har ordet : Sociologidagarna 2012 – 50-årsjubileum och ett nytt format för Sociologidagarna!

Sociologisk Forsknings digitala arkiv

Redaktörerna har ordet : Sociologisk Forskning under 50 år

Sociologisk Forsknings digitala arkiv

Redaktörerna har ordet : Sociologisk Forskning 50 år

Sociologisk Forsknings digitala arkiv

Simple Question, Complex Answer : Pathways Towards a 50% Decrease in Building Energy Use

Addressing building energy use is a pressing issue for building sector decision makers across Europe. In Sweden, some regions have adopted a target of reducing energy use in buildings by 50% until 2050. However, building codes currently do not support as ambitious objectives as these, and novel approaches to addressing energy use in buildings from a regional perspective are called for. The purpose of this licentiate thesis was to provide a deeper understanding of most relevant issues with regard to energy use in buildings from a broad perspective and to suggest pathways towards reaching the long-term savings objective. Current trends in building sector structure and energy use point to detached houses constructed before 1981 playing a key role in the energy transition, especially in the rural areas of Sweden. In the Swedish county of Dalarna, which was used as a study area in this thesis, these houses account for almost 70% of the residential heating demand. Building energy simulations of eight sample houses from county show that there is considerable techno-economic potential for energy savings in these houses, but not quite enough to reach the 50% savings objective. Two case studies from rural Sweden show that savings well beyond 50% are achievable, both when access to capital and use of high technology are granted and when they are not. However, on a broader scale both direct and indirect rebound effects will have to be expected, which calls for more refined approaches to energy savings. Furthermore, research has shown that the techno-economic potential is in fact never realised, not even in the most well-designed intervention programmes, due to the inherent complexity of human behaviour with respect to energy use. This is not taken account of in neither current nor previous Swedish energy use legislation. Therefore an approach that considers the technical prerequisites, economic aspects and the perspective of the many home owners, based on Community-Based Social Marketing methodology, is suggested as a way forward towards reaching the energy savings target.