Sökning: "Transients"

Visar resultat 21 - 25 av 173 avhandlingar innehållade ordet Transients.

1. 21. Development and Applications of a General Coupled Thermal-hydraulic/Neutronic Model for the

   Författare :Mathias Stålek; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reactor transients; measurements; thermal-hydraulics; core calculations; coupled calculations;

   Sammanfattning : Coupled calculations are important for the simulation of nuclear power plants when there is a strongfeedback between the neutron kineticsand the thermal-hydraulics. A general coupled model of the Ringhals-3 Pressurized Water Reactor has beendeveloped for this purpose. LÄS MER

3. 22. Particulate Formation in GDI Engines

   Författare :Sreelekha Etikyala; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; PM; Alternate fuels; Gasoline Direct Injection; internal combustion engines; Particulate Number; Load transients;

   Sammanfattning : The need to comply with stringent emission regulations while improving fuel economy and reducing criteria pollutant emissions from transportation presents a major challenge in the design of gasoline Direct Injection (DI) engines because of the adverse effects of ultrafine Particulate Number (PN) emissions on human health and other environmental concerns. With upcoming advances in vehicle electrification, it may be the case that electric vehicles completely replace all current vehicles powered by internal combustion engines ensuring zero emissions. LÄS MER

4. 23. Overcoming the Mass Transport Limitations of Dye-Sensitised Solar Cells : Towards highly efficient and robust alternative redox mediator electrolyte DSSCs

   Författare :Roger Jiang; Gerrit Boschloo; Erik Johansson; Anders Hagfeldt; Frédéric Sauvage; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dye-sensitised solar cell; dye-sensitized solar cell; photoelectrochemical cell; cobalt tris bipyridine ; mass transport; photocurrent transients;

   Sammanfattning : Dye-sensitised solar cells (DSSCs) have been subject to decadelong research interest, and may have some potential niche market applications. Recently, major advances in power conversion efficiencies have been achieved following the transition to cobalt polypyridine based redox mediators. LÄS MER

5. 24. Dynamik i fjärrvärmesystem

   Författare :Gunnar Larsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; district heating networks; heat load models; district heating systems; hydraulic transients; temperature dynamics; operational strategies;

   Sammanfattning : The purpose of this study is to gain understanding of the dynamic phenomena, which exist in district heating systems. Particularly, the importance of the network is noticed, where pressure waves and temperature waves play a major role. Most of the presented results are obtained by simulations. In many cases these are verified with measurements. LÄS MER

7. 25. Voltage Transients in the Field Winding of Salient Pole Wound Synchronous Machines : Implications from fast switching power electronics

   Författare :Roberto Felicetti; Urban Lundin; Jon Kjellin; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; apparent resistance; cable modeling; current control; transmission line model; eddy currents; field winding; frequency analysis response; Fourier Transform; impedance mismatch; main inductance; overvoltage; parasitic capacitance; partial discharge; quality factor; ringing; slew rate; stray inductance; voltage gradient; winding resonance frequency;

   Sammanfattning : Wound Field Synchronous Generators provide more than 95% of the electricity need worldwide. Their primacy in electricity production is due to ease of voltage regulation, performed by simply adjusting the direct current intensity in their rotor winding. LÄS MER