Sökning: "electromagnetic-fields"

Visar resultat 1 - 5 av 85 avhandlingar innehållade ordet electromagnetic-fields.

  1. 1. Features and Origin of Electromagnetic Fields Generated by Lightning Flashes

    Författare :Mohd Muzafar Ismail; Vernon Cooray; Farhad Rachidi; Uppsala universitet; []
    Nyckelord :negative cloud-to-ground lightning flashes; HF and VHF radiation; chaotic pulse trains; lightning initiation; zero-crossing time; electromagnetic fields; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Sammanfattning : Negative cloud-to-ground (CG) lightning flashes transport negative charge from cloud to ground. Negative ground flashes typically involve various processes identified as preliminary breakdown, stepped leader, return stroke, dart leader, dart-stepped leader, subsequent return stroke, and cloud activity between strokes, such as regular pulse trains and chaotic pulse trains. LÄS MER

  3. 2. Extremely low and microwave frequency electromagnetic fields : influence on biological systems

    Författare :Elisabeth Saalman; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Electromagnetic fields; extremely low frequency; diatom motility; biological effects; cyclotron resonance Chinese hamster V79 cells; membrane permeability transmembrane channels; liposomes; microwave frequency;

    Sammanfattning : .... LÄS MER

  4. 3. Office work and physical factors : health aspects of electromagnetic fields and light

    Författare :Monica Sandström; Kjell Hansson Mild; Gunnar Nordberg; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Facial skin symptoms; office illness; electrical hypersensitivity; physical environment; flicker; jitter; neurophysiological effects;

    Sammanfattning : The overall aim of this thesis is to increase our knowledge of the physical environment of office workers with special focus on electromagnetic fields and to address the question of whether electromagnetic fields can directly or indirectly contribute to symptoms or discomfort among video display terminal ( VDT) workers. Furthermore, we have measured light modulation from various commonly used light sources in laboratory conditions and, as a second step, used modulated light as stimulus for provocation of neurophysiological responses in persons with perceived “electrical hypersensitivity” (EHS). LÄS MER

  5. 4. Electromagnetic Fields in Moving and Inhomogeneous Media

    Författare :Paul Piwnicki; KTH; []
    Nyckelord :Moving Media; Light; Genaral Relativity;

    Sammanfattning : The present thesis deals with electromagnetic effectscreated by the motion or inhomogeneity of a dielectricmedium.In the first paper the quantum R\"ontgen effect isdiscussed. Here a rotating Bose-Einstein condensate -- oranother kind of quantum fluid -- is placed in a chargedcapacitor. The medium's rotation creates a magnetic field. LÄS MER

  7. 5. Idiopathic environmental intolerance attributed to electromagnetic fields : physiological and psychological aspects

    Författare :Amanda Johansson; Lena Hillert; Umeå universitet; []
    Nyckelord :electrical hypersensitivity; EHS; mobile phone; MP; heart rate variability; HRV; provocation study; radiofrequency field; Occupational and Environmental Medicine; arbets- och miljömedicin;

    Sammanfattning : This thesis aims to increase the knowledge on people with symptoms attributed to electromagnetic fields (EMF) by investigating the effects of EMF exposure and by additional description of the heterogeneous group of people reporting EMF-related symptoms. The effect of mobile phone (MP)-like radio frequency (RF) fields on symptoms, autonomic nervous system (ANS) parameters, short-term memory, and reaction time in persons with MP-related symptoms (MP participants) was investigated in a provocation study. LÄS MER