Sökning: "Attenuation"

Visar resultat 36 - 40 av 409 avhandlingar innehållade ordet Attenuation.

1. 36. 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

3. 37. Attenuation of boundary layer disturbances by means of streamwise vortices

   Författare :Sohrab Sattarzadeh Shirvan; Jens H. M. Fransson; Valery Chernoray; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer stability; Tollmien-Schlichting waves; oblique waves; transition to turbulence; streamwise vortices; miniature vortex generators; instability control; drag reduction;

   Sammanfattning : The stability of the boundary layer developed on a flat plate is studied in the presence of streamwise streaks where disturbances of different types are introduced in the wall-bounded shear layer. The experimental investigations are aimed at flow control by means of passively damping the energy growth of the disturbances in the streaky boundary layer and furthermore delay the onset of the transition in the streamwise direction. LÄS MER

4. 38. Methods Used in Quality Assurance and Optimization in Nuclear Medicine Imaging and Imaging Systems

   Författare :Sven-Åke Starck; Sten Carlsson; Göteborgs universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; phantom; image quality; attenuation coefficients; detective quantum efficiency DQE ; digital filtering; iterative reconstruction; bone scintigraphy; bone SPECT; visual grading analysis VGA ; ROC-analysis;

   Sammanfattning : .... LÄS MER

5. 39. Fate of Pharmaceuticals and Their Transformation Products in Rivers : An integration of target analysis and screening methods to study attenuation processes

   Författare :Zhe Li; Anna Sobek; Michael McLachlan; Michael Radke; Kathrin Fenner; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pharmaceuticals; transformation products; fate; river; suspect screening; non-target screening; Applied Environmental Science; tillämpad miljövetenskap;

   Sammanfattning : Pharmaceuticals are environmental contaminants causing steadily increasing concern due to their high usage, ubiquitous distribution in the aquatic environment, and potential to exert adverse effects on the ecosystems. After being discharged from wastewater treatment plants (WWTPs), pharmaceuticals can undergo transformation processes in surface waters, of which microbial degradation in river sediments is considered highly significant. LÄS MER

7. 40. Attenuation of hand-held machine vibrations. Application of non-linear tuned vibration absorber

   Författare :Hans Lindell; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Impact machine; Hand-arm vibration; High frequency vibration; ATVA; Nonlinear tuned vibration absorber; White finger; HAVS; Transient vibration; Auto Tuned Vibration Absorber; Vibration dynamics; ISO 5349;

   Sammanfattning : Vibration injury in the hand-arm system from vibrating hand-held machines is one of the most common occupational health injuries and causes severe and often chronic nerve and vascular injuries to the operator. The objective with this study is to contribute to reduce hand-arm vibration injuries, first by developing methods of redesigning machines that will lower their vibration level and second to study how high frequency vibrations (HFV) above 1250 Hz effect the finger tissue which are not included in the current standard for risk evaluation. LÄS MER