Search for dissertations about: "noise barriers"

Showing result 1 - 5 of 20 swedish dissertations containing the words noise barriers.

2. 1. Prediction and Optimisation of Traffic Noise. A Study on Noise Barriers and Shielded Areas

   Author : Pontus Thorsson; Chalmers University of Technology; []
   Keywords : city canyon; absorption; city noise; insertion loss; traffic noise; soundscape; silent side; noise barrier; ground impedance;

   Abstract : The main contribution of noise levels in cities is today road traffic. The strongest source for all road vehicles is most often the tyre-road contact. This source position close to the ground is fortunate with respect to secondary noise abatement measures, such as absorbing road surfaces or noise barriers. READ MORE

4. 2. Road traffic noise reduction by multiple scattering and absorption mechanisms

   Author : Bart van der Aa; Chalmers University of Technology; []
   Keywords : Outdoor sound propagation; Sonic crystals; Road traffic noise; FDTD; Noise barriers; MST; Porous materials; 2.5D MST; Graded index sonic crystals;

   Abstract : Millions of people in Europe, and even more on a global scale, are affected by environ- mental noise. Traffic related noise is estimated to cause a yearly loss of approximately one million healthy life years in Western Europe, which is mostly related to road traffic noise. READ MORE

5. 3. On the Directivity of Railway Noise Sources

   Author : Xuetao Zhang; Chalmers University of Technology; []
   Keywords : 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;

   Abstract : 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. READ MORE

6. 4. Background road traffic noise synthesis

   Author : Georgios Zachos; Chalmers University of Technology; []
   Keywords : NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; background traffic noise synthesis; auralisation; urban sound planning;

   Abstract : As urban planning evolves along with societal life, new requirements that should be met are rising. One of those, is the inclusion of acoustic quality in urban environments, before, during, or after a planning process. To address this for a yet to be built area, metrics are needed that try to quantify acoustic quality. READ MORE

7. 5. Graded index sonic crystal noise barriers: An introduction to design and optimization

   Author : Bart van der Aa; Chalmers University of Technology; []
   Keywords : NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; Shape optimal design; Broadband acoustic lens; Optimization; Outdoor sound propagation; Sonic crystal noise barrier; Graded index sonic crystal;

   Abstract : Environmental noise pollution and its impact on human beings remains to be an important topic in acoustics. Conservative estimations of the World Health Organization have shown that traffic related noise alone causes a loss of approximately one million healthy life years, only within Western Europe. READ MORE