Search for dissertations about: "frequency balance"

Showing result 1 - 5 of 144 swedish dissertations containing the words frequency balance.

  2. 1. Low frequency noise during work. Effects on performance and annoyance

    Author : Johanna Bengtsson; Göteborgs universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Low frequency noise; performance; workload; annoyance; cortisol; subjective stress; subjective sensitivity to noise; sound characteristics; frequency balance; modulation frequency;

    Abstract : Aims. Low frequency noise (LFN) is defined as "a noise with a dominant frequency content of 20 to 200 Hz". Common sources of LFN in occupational environments are ventilation, heating and air-conditioning systems, computer network installations and compressors. READ MORE

  4. 2. Symmetric varactor frequency multipliers

    Author : Mattias Ingvarson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sub-millimetre wave; heterostructure barrier varactor HBV ; symmetric varactor; frequency multiplier; millimetre wave; semiconductor diode;

    Abstract : This thesis describes heterostructure barrier varactor (HBV) frequency multipliers for millimetre and sub-millimetre wave applications.The basic principles of HBVs are explained. Starting from basic varactor theory, an equivalent circuit model for HBVs is presented. READ MORE

  5. 3. Impaired balance and fall risk in people with multiple sclerosis

    Author : Anna Carling; Ylva Nilsagård; Anette Forsberg; Sverker Johansson; Örebro universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Balance; exercise; falls; falls efficacy; gait; multiple sclerosis; next of kin; physiotherapy; qualitative research; randomized controlled trial;

    Abstract : The symptoms from the neurological disease multiple sclerosis vary from person to person and over time. Impaired balance is common in people with multiple sclerosis and can lead to falls. Fall frequency is high in people with multiple sclerosis, above 50%. Multiple sclerosis affects not only the person having the disease but also their next of kin. READ MORE

  6. 4. Studies in Glacier Mass Balance : Measurement and its errors

    Author : Andrew Mercer; Peter Jansson; Gunhild Rosqvist; Ian Brown; Jonathan Carrivick; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Glaciology; Mass Balance; Measurement Errors; Physical Geography; naturgeografi;

    Abstract : The study of the surface mass balance of valley glaciers has a long history but one that is dogged by uncertainty and errors, and uncertainty about those errors. These problems are acknowledged by the glaciological community and have been examined and formalised in several publications. READ MORE

  7. 5. Frequency Response by Wind Farms in Islanded Power Systems with High Wind Power Penetration

    Author : Mattias Persson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Synthetic inertia; rate of change of frequency; inertia emulation; variable speed wind turbine; frequency control;

    Abstract : The integration of variable speed wind turbines (VSWT) in power systems keep increasing inorder to reduce the emission of green house gases. This increase of power electronic converterinterfaced generation causes a decrease of power system inertia and issues previously existingin power systems tend to become more complicated and new solutions should be evaluated. READ MORE