Sökning: "noise emission"

Visar resultat 1 - 5 av 110 avhandlingar innehållade orden noise emission.

1. 1. Vertical Axis Wind Turbines : Tower Dynamics and Noise

   Författare :Erik Möllerström; Jonny Hylander; Fredric Ottermo; Göran Sidén; Hans Bernhoff; Mats Åbom; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VAWT; H-rotor; eigenfrequency; semi-guy-wired tower; noise emission; sound power level;

   Sammanfattning : Vertical axis wind turbines (VAWTs) have with time been outrivaled by the today common and economically feasible horizontal axis wind turbines (HAWTs). However, VAWTs have several advantages such as the possibility to put the drive train at ground level, lower noise emissions and better scaling behavior which still make them interesting for research. LÄS MER

3. 2. On the Directivity of Railway Noise Sources

   Författare :Xuetao Zhang; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; railway traction noise; railway rolling noise; line source; railway aerodynamic noise; moving source; equivalent source line; De-Dopplerization; sound emission time; sound immission time; directivity; the Doppler factor;

   Sammanfattning : This dissertation deals with the directivity of railway noise. The directivity of railway noise is of particular importance when we have high-rise buildings close to the track, tunnel openings, partial barriers, or when we calculate the maximum sound pressure level during a pass-by based on the sound power level of the different sub-sources of a train. LÄS MER

4. 3. On Performance of Digital Radio Receiver in Non-Gaussian Interference

   Författare :Kia Wiklundh; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bandwidth conversion; performance estimation; APD; interference; minimum shift keying; man-made noise; Gaussian approximation; measurement; emission requirements; non-Gaussian interference; micro-wave oven; MSK; amplitude probability distribution; emission;

   Sammanfattning : Interference from electrical equipment can degrade a co-located digital radio receiver severely. To avoid this performance degradation it is necessary to have estimation methods to predict the influence from an interference environment on a radio receiver in advance. LÄS MER

5. 4. A new approach for considering the interference impact on digital radio systems from complex interference environments

   Författare :Kia Wiklundh; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; minimum shift keying; class A; amplitude probability distribution; bandwidth conversion; Gaussian approximation; emission; non-Gaussian interference; performance estimation; man-made noise; measurement; emission requirements; micro-wave oven; MSK; coding gain; APD; interference;

   Sammanfattning : Interference from electrical equipment can severely degrade aco-located digital radio receiver. To avoid such performance degradation, it isnecessary to have estimation methods to predict the influence of an interferenceenvironment on a radio receiver. LÄS MER

7. 5. Physics-based Modelling for Aircraft Noise and Emission Predictions

   Författare :Evangelia Maria Thoma; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; measurements; trajectories.; emissions; interdependencies; FDR; turbofan engine; aircraft noise; physics-based modelling;

   Sammanfattning : Starting from semi-empirical noise source models for the aircraft and 4D trajectory computations, this work focuses on the environmental assessment of scenario studies regarding technology evaluation and procedural planning. Extensive work was performed on improving and validating the existing tools. LÄS MER