Sökning: "metro"

Visar resultat 26 - 30 av 30 avhandlingar innehållade ordet metro.

  1. 26. Rail Corrugation Growth on Curves

    Författare :Peter Torstensson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; short-pitch rail corrugation; rotating flexible wheelset model; small radius curves; prediction of long-term roughness growth; plastic deformation; non-Hertzian and non-steady wheel‒rail contact; wear; rutting corrugation;

    Sammanfattning : The development of periodic irregularities with distinct wavelengths (corrugation) on the low rail of small radius curves is studied through mathematical modelling, numerical simulations, field measurements and laboratory investigations. One year of monitoring of roughness on the low rail of a 120 m radius curve on the metro of Stockholm Public Transport (SL) showed severe growth of rail corrugation with wavelengths of about 5 cm and 8 cm. LÄS MER

  3. 27. Epitaxial growth optimization for 1.3-um InGaAs/GaAs Vertical-Cavity Surface-Emitting lasers

    Författare :Zhenzhong Zhang; Mattias Hammar; Nicolae Chitica; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; VCSEL MOVPE InGaAs GaAs quantum wells; Semiconductor physics; Halvledarfysik;

    Sammanfattning : Long-wavelength (1.3-μm) vertical-cavity surface-emitting lasers (VCSELs) are of great interest as low-cost, high performance light sources for fiber-optic metro and access networks. During recent years the main development effort in this field has been directed towards all epitaxial GaAs-based structures by employing novel active materials. LÄS MER

  4. 28. Studies on experimental anaerobic infections of the middle ear and on the polymorphonuclear leukocyte function under anaerobic conditions

    Författare :Magnus Thore; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Otitismedia; anaerobicbacteria; experimental; nitroimidazoles; antibody; phagocytosis; anaerobiosis;

    Sammanfattning : Despite the clinical importance of anaerobic bacteria in otitis media and the uncertainty regarding the proper treatment of the anaerobic focal infection, few experimental studies focused upon the role of these microorganisms in otitis media have been publis­hed. In the present investigation a guinea-pig model for the induc­tion of anaerobic monoinfections in the middle ear was described. LÄS MER

  5. 29. Congestion Effects in Transport Modelling and Forecasting

    Författare :Jens West; Maria Börjesson; Carlo Giamoco Prato; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transportvetenskap; Transport Science;

    Sammanfattning : Transport investments and policies are increasingly turned towards dealing with transport congestion rather than with shortening the potential free flow travel time. However, appraisal methodologies for projects meant to reduce congestion are relatively less well developed compared to methodologies for projects aiming to reduce travel times. LÄS MER

  7. 30. Moment Method Analysis of Antennas on Cylindrical Structures by Using G2DMULT and Design of Hat Fed Reflector Antennas

    Författare :Jian Yang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; G2DMULT; reflector antenna; paraboloid; dipole; base station antenna; screw heads; vertex plate; self impedance; G1DMULT; ring-shaped phase center; radiation efficiency; FDTD; cylindrical structures; V2D; ring-focus; moment method;

    Sammanfattning : This thesis deals with two aspects of research interest: moment method analysis of antennas on cylindrical structures by using G2DMULT, and design of hat fed reflector antennas. Both of them are two-dimensional (2D) structure problems, one being cylindrical and the other rotationally symmetric. LÄS MER