Sökning: "Electric fields"

Visar resultat 1 - 5 av 235 avhandlingar innehållade orden Electric fields.

  1. 1. Auroral Electric Fields From Satellite Observations and Numerical Modelling

    Författare :Tomas Karlsson; KTH; []
    Nyckelord :Satellite measurements; electric fields; ionosphere; magnetosphere; diverging electric fields; downward current region; black aurora; westward travelling surge; auroral bulge; subauroral ion drifts SAID ; subauroral electric fields SAEF ; mid-latit; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : This thesis is about electrodynamics of thehigh-latitude/auroral region of near-Earth space. The work ismainly based on electric field measurements made by the doubleprobe instrument on the Freja satellite at altitudes ofapproximately 800-1700 km, together with measurements fromother instruments on the same satellite, and ground-basedinstrumentation. LÄS MER

  3. 2. Radiofrequency fields : exposure, dose and health

    Författare :Jonna Wilén; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electromagnetic fields; SAR; Specific Absorption; subjective symptoms;

    Sammanfattning : The overall aim of this thesis is to increase our knowledge of relevant exposure parameters when discussing possible health implication from exposure to radiofrequency electromagnetic fields (RF), especially effects that might occur at non-thermal levels.In this thesis an effort is made to broaden the exposure assessment and to take the exposure time into account and combine it with the Specific Absorption Rate (SAR) and the field parameters (electric and magnetic field strength) to approach a dose concept. LÄS MER

  4. 3. Pulsed Electric Field Food Treatment and Low Frequency Bioelectromagnetics

    Författare :Martin Lindgren; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; extremely low frequency; non-thermal microbial inactivation; electromagnetic fields; biological effects; treatment chambers; electric field distribution; magnetic fields; pulsed electric fields;

    Sammanfattning : This thesis is divided in two parts, both of which address the interaction between biological cells (especially cell membranes) and electromagnetic fields. The first part deals with the application of intense pulsed electric fields (PEF) in foods. It is intended to be a non-thermal method to inactivate microorganisms. LÄS MER

  5. 4. Electric Fields for Surface Design and Chemical Analysis

    Författare :Christian Ulrich; Fredrik Björefors; Ingemar Lundström; Tautgirdas Ruzgas; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Electric fields; Surface design; Chemical analysis; Bipolar electrodes; Impedance spectroscopy; Electrochemistry; Elektrokemi; Chemical physics; Kemisk fysik; Physical chemistry; Fysikalisk kemi; Surface and colloid chemistry; Yt- och kolloidkemi;

    Sammanfattning : This thesis deals with the use of electric fields for evaluation and control of chemical systems. An electric field can result in the flow of charge across an interface between a metal and a solution, by means of chemical reactions. This interplay between electricity and chemistry, i.e. LÄS MER

  7. 5. Investigations of auroral electric fields and currents

    Författare :Tommy Johansson; Göran Marklund; Kristina Lynch; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; auroral physics; auroral electric fields; auroral potential structures; auroral particle acceleration; Space physics; Rymdfysik;

    Sammanfattning : The Cluster spacecraft have been used to investigate auroral electric fields and field-aligned currents (FACs) at geocentric distances between 4 and 7 Re. The electric fields have been measured by the EFW instrument, consisting of two pairs of spherical probes, and the FACs have been calculated from measurements of the magnetic field by the FGM fluxgate magnetometer. LÄS MER