Sökning: "frequency effects"

Visar resultat 1 - 5 av 964 avhandlingar innehållade orden frequency effects.

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

    Detta är en avhandling från Göteborg

    Författare :Johanna Bengtsson; Göteborgs universitet.; Gothenburg University.; [2003]
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

  2. 2. Sleep disordered breathing at work : Cause and effects

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Jan Ulfberg; Uppsala universitet.; [1999]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Medical sciences; Snoring; sleepiness; sleep apnea; epidemiology; organic solvents; work performance; occupational accidents; MEDICIN OCH VÅRD; MEDICINE; MEDICIN; arbets- och miljömedicin; Occupational and Environmental Medicine;

    Sammanfattning : The recent discovery of obstructive sleep apnea syndrome (OSAS) as a prevalent disorder has highlightedthe fact that snoring is not just a harmless noise. Snoring and OSAS in the work milieu has hardly beeninvestigated, which makes it important to identify both risk factors and consequences in the work place. LÄS MER

  3. 3. Health effects of heatwaves short and long term predictions

    Detta är en avhandling från Umeå : Umeå Universitet

    Författare :Christofer Åström; Umeå universitet.; [2017]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Heatwave; health impact assessment; early warning system; mortality; morbidity; climate change;

    Sammanfattning : Background: Climate change is defined by the Intergovernmental Panel on Climate Change as changes in the state of the climate associated with changes in the mean and/or the variability of its properties. Climate change will affect temperatures both as an increase in mean temperature as well as changes in the frequency of temperature extremes. LÄS MER

  4. 4. Modelling approaches for audio frequency power transformers

    Detta är en avhandling från Stockholm : Elektrotekniska system

    Författare :Julius Krah; KTH.; [2003]
    Nyckelord :power transformer; audio frequency; loss; hysteresis; eddy currents; skin effect. Leakage inductance;

    Sammanfattning : The development of HVDC converters, local generation andtractions systems increases the demand for power converters.While a lot of studies have been conducted on the powerelectronics, there are still open questions concerning thecontained power transformer that operates at a few kilohertz. LÄS MER

  5. 5. Buffer Related Dispersive Effects in Microwave GaN HEMTs

    Detta är en avhandling från ; Chalmers tekniska högskola; Gothenburg

    Författare :Johan Bergsten; [2018]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; trapping effects; C-doping; AlGaN GaN interface quality; recessed ohmic contacts; GaN HEMT; buffer design;

    Sammanfattning : In applications such as mobile communication and radar, microwave power generation at high frequency is of utmost importance. The GaN HEMT offers a unique set of properties that makes it suitable for high power amplification at high frequencies. LÄS MER