Sökning: "TDR measurement"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden TDR measurement.

1. 1. Electromagnetic dispersion modeling and analysis for HVDC power cables

   Författare :Stefan Gustafsson; Sven Nordebo; Martin Norgren; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; HVDC power cables; electromagnetic model; TDR measurement; sensitivity analysis; dispersion relation; propagation constant; low-frequency asymptotics;

   Sammanfattning : Derivation of an electromagnetic model, regarding the wave propagation in a very long (10 km or more) High Voltage Direct Current (HVDC) power cable, is the central part of this thesis. With an existing “perfect” electromagnetic model there are potentially a wide range of applications. LÄS MER

3. 2. Water and Heat Transport in Road Structures : Development of Mechanistic Models

   Författare :Klas Hansson; Lars-Christer Lundin; Kurt Roth; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydrology; Water flow; Heat flow; Unsaturated flow; Freeze-thaw; Numerical models; Uncertainty analysis; Sensitivity analysis; Roads; Overland flow; Flow patterns; TDR; Water content reflectometer; Calibration; Fractures; Hydrologi; Hydrology; Hydrologi;

   Sammanfattning : The coupled transport of water and heat, involving freezing and thawing, in the road structure and its immediate environment is important to consider for optimal design and maintenance of roads and when assessing solute transport, of e.g. de-icing salt, from roads. LÄS MER

4. 3. Time and Frequency Domain Measurement Methods for High Frequency Characterisation of Power Cables

   Författare :Ruslan Papazyan; KTH; []
   Nyckelord :Attenuation measurement; XLPE insulation; Power cables;

   Sammanfattning : Time Domain Reflectometry (TDR) has been used forlocalisation of transmission line discontinuities in variousapplications. One of the challenges when applying TDR on powercables is to obtain knowledge of the high frequencycharacteristics of both the degraded and the undegradedsections of the cable. LÄS MER

5. 4. Techniques for Localization of Insulation Degradation along Medium-Voltage Power Cables

   Författare :Ruslan Papazyan; Roland Eriksson; Fred Steennis; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; Attenuation measurement; cross-linked polyethylene insulation; discontinuities; localization; mass-impregnated insulation; numerical analysis; parameter estimation; power cable metallic screen; scattering parameters; time domain reflectometry; velocity measurements; water treeing; Elkraftteknik; Electric power engineering; Elkraftteknik;

   Sammanfattning : Time Domain Reflectometry (TDR) has been used for localization of transmission line discontinuities in diverse applications. Various challenges have to be addressed when applying TDR for localization of insulation degradation in power cables. LÄS MER

7. 5. Factors Affecting Rates of Change in Soil Bacterial Communities

   Författare :Marie Pettersson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; virology; mycology; Mikrobiologi; bakteriologi; virologi; mykologi; Plant ecology; Växtekologi; bacteriology; Microbiology; DGGE; PLFA; TdR-incorporation; function; structure; tolerance; adaptation; pH; soil bacterial community; temperature;

   Sammanfattning : The soil bacterial community is under the constant influence of its environment. Changing any of the factors affecting the bacterial community will induce a selection pressure which, with time, will change the community. In this work the effect of changing the temperature or pH on the soil bacterial community was studied. LÄS MER