Sökning: "commuter"

Visar resultat 21 - 25 av 26 avhandlingar innehållade ordet commuter.

1. 21. Simulation of Wheel and Rail Profile Evolution : Wear Modelling and Validation

   Författare :Roger Enblom; KTH; []
   Nyckelord :contact; wear; wear prediction; wear model; wheel profile; rail profile; simulation vehicle-track interaction; multibody simulation; MBS; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Numerical procedures for reliable wheel and rail wearprediction are rare. Recent development of simulationtechniques and computer power together with tribologicalknowledge do however suggest computer aided wear prediction. LÄS MER

3. 22. School choice, space and the geography of marketization- Analyses of educational restructuring in upper secondary education in Sweden

   Författare :Anna Maria Fjellman; Göteborgs universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; school choice; school market; marketization; space; equity; quasi-market; differentiation; spatial justice;

   Sammanfattning : The main aim of the dissertation is to investigate, analyze and create a research-based understanding of the spatialities of the Swedish school choice in upper secondary education using a socio-spatial framework. The dissertation is comprised of three empirical studies based on six cohorts of register data from The Gothenburg Longitudinal Database. LÄS MER

4. 23. Quasi-analytical Modelling and Optimisation Techniques for Transport Aircraft Design

   Författare :Askin T. Isikveren; KTH; []
   Nyckelord :aircraft; conceptual; design; specifications; atmosphere; geometry; weight; aerodyanmics; propulsion; operational performance; stability and control; constrained multi-objective optimisation; computer aided design; regional; business; high-transonic; ;

   Sammanfattning : The research work presented here focuses on the subject oftransport aircraft design at the pre-design or conceptuallevel. The primary topics addressed are: (1) generation of avast array of new quasi-analytical expressions to permit aconceptual treatment of commercial and business transportaircraft with adequate sensitivity for more advanced tradestudies; (2) review and adoption of a method to predictstability and control characteristics (using the Mitchellmethod); (3) a study of the relative merits between variousmethods in facilitating an expedient and robust constrainedmulti-objective optimisation result within the context oftraditional conceptual design problems (Genetic Algorithms andNelder-Mead Simplex search); (4) creation of a software packageas a new and unique conceptual tool that permits the generationof design proposals in an accurate yet expeditious manner; and,(5) practical demonstration of the new conceptual designsoftware package by undertaking some actual aircraft designproposals. LÄS MER

5. 24. Shear cracks in concrete structures subjected to in-plane stresses

   Författare :Richard Malm; Håkan Sundquist; Kent Gylltoft; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shear; plane state stress; crack width; FE analysis; design standards; serviceability state; Civil engineering and architecture; Samhällsbyggnadsteknik och arkitektur;

   Sammanfattning : After only two years of service, extensive cracking was found in the webs of two light-rail commuter line bridges in Stockholm, the Gröndal and Alvik bridges. Due to this incident it was found necessary to study the means available for analysing shear cracking in concrete structures subjected to in-plane stresses. LÄS MER

7. 25. Simulation and Measurement of Wheel on Rail Fatigue and Wear

   Författare :Babette Dirks; Mats Berg; Roger Enblom; Mark Burstow; KTH; []
   Nyckelord :multibody simulations; prediction; wear; RCF; wheel; rail; cracks; measurements; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : The life of railway wheels and rails has been decreasing in recent years. This is mainly caused by more traffic and running at higher vehicle speed. LÄS MER