Sökning: "variable speed"

Visar resultat 16 - 20 av 191 avhandlingar innehållade orden variable speed.

1. 16. Accidents between pedestrians, bicyclists and motorized vehicles: Accident risk and injury severity

   Författare :Höskuldur Kröyer; Trafik och väg; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Accidents; pedestrians; bicyclists; exposure; risk; consequence; speed; age.;

   Sammanfattning : The aims of this work are to better understand (1) the relation between exposure and the risk of an accident between pedestrians and motorized vehicles and between bicyclists and motorized vehicles occurring at urban intersections and (2) how the speed environment and the victim´s age relate to the injury severity/outcome once a pedestrian or a bicyclist has been struck by a motorized vehicle. Cross sectional studies are used, and the relations are analyzed using multinomial logit models, negative binomial regression and other statistical methods. LÄS MER

3. 17. Electrical System for a Variable Speed Vertical Axis Wind Turbine

   Författare :Senad Apelfröjd; Uppsala universitet; []
   Nyckelord :;

   Sammanfattning : The wind has been used as a source of energy for a long time. Wind power in power production has had a upswing in the last decade due to its renewable and clean nature. This thesis contributes to the wind power research done at the division of Electricity at Uppsala University. LÄS MER

4. 18. Modulation, efficiency and lifetime of two-level and multilevel converters for a hydropower application

   Författare :Chengjun Tang; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Pumped-storage hydropower; pulse width modulation; losses; modular multilevel converter; efficiency; variable speed; converter; lifetime; space vector modulation; thermal modelling; neutral point clamped converter;

   Sammanfattning : Along with the integration of the renewable energy in the electrical grid, the pumped-storage hydropower has gained more and more attention due to its fast response and energy storage ability. To have a higher overall efficiency and more flexibility of the system, variable speed is preferred in the operation of the pumped-storage hydropower applications. LÄS MER

5. 19. Modeling and Linear Quadratic Optimal Control of Wind Turbines

   Författare :Thommy Ekelund; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; periodic system; structural dynamics; yaw control; variable speed; wind turbines; active stall; estimation; LQG; identification;

   Sammanfattning : Control can improve the performance of wind turbines by enhancing the energy capture and reducing dynamic, as well as static, loads. There are several possible configurations of the control system, depending on the available actuators. LÄS MER

7. 20. Predictive models for accidents on urban links - A focus on vulnerable road users

   Författare :Thomas Jonsson; Trafik och väg; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Road transport technology; Transportteknik; Transport technology; Teknik; Technological sciences; Stads- och glesbygdsplanering; Town and country planning; speed; links; urban; safety; vulnerable road users; modelling; prediction; crash; traffic safety; accident; Vägtransportteknik;

   Sammanfattning : Much of earlier work on predictive models for accidents has been focused on rural traffic or urban intersections. This work has aimed at identifying and investigating possible improvements to predictive models for accidents on urban links. A special focus has been on the accidents of vulnerable road users. LÄS MER