Sökning: "dielectric spectroscopy"

Visar resultat 16 - 20 av 90 avhandlingar innehållade orden dielectric spectroscopy.

1. 16. The Effect of HV Impulses on Partial Discharge Activity and on the Dielectric Response in Oil-impregnated Paper Insulation

   Författare :Respicius Clemence Kiiza; Hans Edin; Jörgen Blennow; KTH; []
   Nyckelord :Partial discharge; high voltage impulses; oil-impregnated paper; dielectric spectroscopy; Finite Element Method.;

   Sammanfattning : This work investigates how HV impulses affect the behavior of partial discharge (PD) activity and the low voltage dielectric response of oil-impregnated paper insulation. It also investigates how the change in the PD activity is related to the degradation level of oil-impregnated paper insulation. LÄS MER

3. 17. Dielectric Properties of Liquid-Impregnated Porous Solids

   Författare :Bo Nettelblad; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fluid-solid interface; porous microstructure; temperature; ion-containing liquid; transport properties of porous media; brine; salinity; electric conduction; models of composite media; interface phenomena; dielectric relaxation; rock;

   Sammanfattning : Dielectric spectroscopy is a versatile tool that can often be used as a non-destructive, indirect way of measuring other important properties (such as content of crude oil or degree of curing of a resin). The dielectric properties of materials are thus of interest in several circumstances and not only for materials used for electrical purposes (such as electrical insulation). LÄS MER

4. 18. Diagnosis of Moisture in Transformer Insulation - Application of frequency domain spectroscopy

   Författare :Chandima Ekanayake; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; moisture content; diagnostic methods; modelling; polarisation depolarisation currents PDC ; frequency domain spectroscopy FDS ; dielectric response measurements; Oil-impregnated pressboard paper insulation; Karl Fischer titration KFT ; conductivity; ageing;

   Sammanfattning : This thesis presents application of dielectric response measurements for identifying condition of high voltage insulation in power transformers. Results of such measurements, incorporated with different modelling techniques, allow to estimate moisture content in solid part of transformer insulation. LÄS MER

5. 19. On-chip terahertz characterisation of liquids

   Författare :Juan Cabello Sánchez; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric permittivity; Through-Reflect-Line TRL calibration; vector network analyzers VNA ; terahertz spectroscopy; isopropyl alcohol IPA ; coplanar waveguides CPW ; water; on-wafer measurements; planar Goubau line; Chip; liquids; microfluidic channels; scattering parameters; material properties;

   Sammanfattning : Spectroscopy at terahertz frequencies can be used in a wide range of applications including radio-astronomy, pharmaceutical manufacturing control, and the study of processes in molecular biology. Biomolecular samples should preferably be studied in their native environment, water, however, water poses extreme attenuation for THz-frequency waves, deteriorating or even impeding analysis using these waves. LÄS MER

7. 20. Dynamics of Disordered Materials in Confined Geometries

   Författare :Christer Svanberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; polymer film; glass transition; confinement; polymer gel; dynamics; dielectric spectroscopy; gel electrolytes; relaxation; photon correlation; cooperativity;

   Sammanfattning : This thesis is concerned with effects of geometrical confinement on dynamics in disordered materials in the nanoscopic range. Of particular interest is the dynamics around the liquid to glass transition. Two systems have been investigated: thin polymer films and polymer gels. LÄS MER