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Visar resultat 1 - 5 av 229 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Sustainable Freight Transport from an Urban Perspective

    Författare :Sönke Behrends; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sustainable transport; urban freight transport; intermodal transport; rail transport; Sustainability;

    Sammanfattning : The trend of growing road freight transport causes significant negative impacts on the society, economy and environment. A substantial share of the road freight sector’s externalities is imposed on urban areas because cities are the main destination for freight flows either for production, consumption or for transfer to other locations. LÄS MER

  3. 2. Radio Frequency InGaAs MOSFETs

    Författare :Navya Sri Garigapati; NanoLund: Centre for Nanoscience; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; III-V compound semiconductor; InGaAs MOSFET; Quantum well; Nanowire; Radio Frequency; Band structure calculation; k.p calculations; Strain engineering; ballistic electron transport; S-parameters;

    Sammanfattning : III-V-based Indium gallium arsenide is a promising channel material for high-frequency applications due to its superior electron mobility property. In this thesis, InGaAs/InP heterostructure radio frequency MOSFETs are designed, fabricated, and characterized. LÄS MER

  4. 3. CFD MODELLING AND EXPERIMENTS ON AERATOR FLOW IN CHUTE SPILLWAYS

    Författare :Penghua Teng; James Yang; Anders Wörman; Anton Schleiss; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spillway Aerator; Cavitation; Air Entrainment; Two-phase Flow; VOF; Mixture Model; Two-Fluid Model; Air Cavity; Cavity Air Pressure; Air Concentration; Shadowgraphic Image Method SIM ; High-speed Particle Image Velocimetry HSPIV ; Bubble Tracking Method BTM ; luftningsramp; kavitation; luftinträngning; tvåfasflöde; VOF; Mixture Model; Two-Fluid Model; luftkavitet; kavitetslufttryck; luftkoncentration; skuggrafisk bildmetod; hastighetsmätning med höghastighetspartikelfotografering; bubbelspårningsmetod; Byggvetenskap; Civil and Architectural Engineering;

    Sammanfattning : A chute spillway is a typical component of large dams for discharging floods. Because of the high water head, the flow velocity in the chute is often in excess of 20 m/s. Consequently, the structure is usually prone to cavitation damages. Flow aeration is evidenced to efficiently eliminate or to mitigate the damages. LÄS MER

  5. 4. Dynamic contact stiffness and air-flow related source mechanisms in the tyre/road contact

    Författare :Julia Winroth; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tyre road noise; Tread modelling; Air-flow related source mechanisms; Air pumping; Tyre road contact;

    Sammanfattning : Two aspect of phenomena occurring in, and in the vicinity of the contact patch formed by a tyre rolling on a road are here investigated: 1. A detailed numerical time domain contact model is used to evaluate approximations of the tread response that are commonly embraced in tyre/road interaction models. 2. LÄS MER

  7. 5. Studies on Building Air Leakage -a transient pressurisation method, measurements and modelling

    Författare :Björn Mattsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; air change rate; Airtightness; CFD-simulations; moisture transport; air leakage; mould growth; cold attics; transient pressurisation;

    Sammanfattning : Airtightness of the building envelope is a key factor for good performance of a building. The main part of this thesis deals with the exploration of a transient pressurisation method for air leakage measurements.In the transient method, an enclosure is pressurised to a desired pressure. The air flow into the enclosure is then stopped. LÄS MER