Sökning: "average velocity"

Visar resultat 16 - 20 av 116 avhandlingar innehållade orden average velocity.

  1. 16. Frosting and Defrosting of Air-Coils

    Författare :Per Fahlén; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; heat pump; defrost; air-coil; air-source; control; frost; optimized;

    Sammanfattning : Experience indicates that air-source heat pumps have more operating problems than ground-source heat pumps. One major factor pertains to the effects of frosting and the subsequent need for defrosting. This thesis reviews previous research and practical experience and presents novel experimental facilities to investigate the process of frosting. LÄS MER

  3. 17. PHYSIOLOGICAL AND BIOMECHANICAL FACTORS DETERMINING CROSS-COUNTRY SKIING PERFORMANCE

    Författare :Erik Andersson; Hans-Christer Holmberg; Glenn Björklund; Thomas Stöggl; Jos J. de Koning; Mittuniversitetet; []
    Nyckelord :cycle characteristics; energy cost; energy yield; incline; joint angles; kinematics; kinetics; mechanics; Nordic skiing; oxygen deficit; oxygen demand; technique transitions; total metabolic rate.;

    Sammanfattning : Cross-country (c.c.) skiing is a complex sport discipline from both physiological and biomechanical perspectives, with varying course topographies that require different proportions of the involved sub-techniques to be utilised. A relatively new event in c. LÄS MER

  4. 18. On the Attachment of Lightning Flashes to Grounded Structures

    Författare :Marley Becerra; Vernon Cooray; Rajeev Thottappillil; Mats Boman; Ivo Gallimberti; Uppsala universitet; []
    Nyckelord :Engineering physics; Lightning; Lightning attachment; Positive leader discharges; Lightning protection; Thunderstorms; Numerical modeling; Teknisk fysik;

    Sammanfattning : This thesis deals with the physical modeling of the initiation and propagation of upward positive leader discharges from grounded structures during lightning strikes. It includes the analysis of upward leaders initiated under the influence of the electric field produced by a dominant negative cloud charge and due to the combined action of a negative thundercloud and a descending downward stepped negative leader. LÄS MER

  5. 19. Experimental Results of a Load-Controlled Vertical Axis Marine Current Energy Converter

    Författare :Johan Forslund; Mats Leijon; Karin Thomas; Jan Sundberg; Tom Blackmore; Uppsala universitet; []
    Nyckelord :Marine Current; Vertical Axis; Load Control; ; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : This thesis investigates the load control of a marine current energy converter using a vertical axis turbine mounted on a permanent magnet synchronous generator. The purpose of this thesis is to show the work done in the so far relatively uncharted territory of control systems for hydro kinetic energy conversion. LÄS MER

  7. 20. Wood chips for kraft and sulfite pulping : evaluation of novel forest-industrial drum-chipping technology

    Författare :Jessica Gard Timmerfors; Leif J. Jönsson; David Blomberg; Sören Östlund; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wood chip; drum chipper; impregnation; pulping; sulfite process; kraft process; Scots pine; Norway spruce; heartwood; frozen wood; moisture content;

    Sammanfattning : Wood chipping and the supply of high-quality wood chips are of critical importance for most forest-industrial processes. The quality of wood chips affects product yield, product quality, and processability. LÄS MER