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Showing result 1 - 5 of 64 swedish dissertations matching the above criteria.

2. 1. Sound propagation from sustainable ground vehicles : from aeroacoustic sources to urban noise

   Author : Nicolas Pignier; Ciarán O'Reilly; Susann Boij; Gwenael Gabard; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sound propagation; sound generation; ground vehicle; aeroacoustics; aerodynamics; Kirchhoff approximation; detached eddy simulation; Ffowcs Williams and Hawkings; ljudutberdning; ljudalstring; markfordon; aeroakustik; aerodynamik; Kirchhoff approximation; detached eddy simulation; Ffowcs Williams and Hawkings; Vehicle and Maritime Engineering; Farkostteknik; Engineering Mechanics; Teknisk mekanik;

   Abstract : Transportation is the main source of environmental noise in Europe, with an estimated 125 million people affected by excessive noise levels from road traffic, causing a burden of noise related diseases and having a substantial economic impact on society. In order to reduce exposure to high levels of traffic noise, two approaches are the topic of extensive research: preventing sound from propagating from roads and railways using for example noise barriers, and reducing the sources of noise themselves. READ MORE

4. 2. A Wave Expansion Method for Aeroacoustic Propagation

   Author : Johan Hammar; Gunilla Efraimsson; Ciarán J. O'Reilly; Wim De Roeck; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sound propagation; Sound generation; Aeroacoustics; Aerodynamics; Computational fluid dynamics; Computational aeroacoustics; Numerical methods; Lighthill; Curle; Ffowcs Williams and Hawkings; Frequency-domain propagation; Wave expansion method.; Vehicle and Maritime Engineering; Farkostteknik;

   Abstract : Although it is possible to directly solve an entire flow-acoustics problem in one computation, this approach remains prohibitively large in terms of the computational resource required for most practical applications. Aeroacoustic problems are therefore usually split into two parts; one consisting of the source computation and one of the source propagation. READ MORE

5. 3. Sound, Light and Electricity : as applications and analysis techniques to study metabolic effect and biofilm characterization of Geobacter sulfurreducens

   Author : Adolf Krige; Paul Christakopoulos; Ulrika Rova; Ashley Franks; Luleå tekniska universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MFC; Microbial fuel cell; Raman microscopy; BES; Geobacter sulfurreducens; Biokemisk processteknik; Biochemical Process Engineering;

   Abstract : ElectricityBio-electrochemical systems such as microbial fuel cells (MFCs) and microbial electrolysis cells have shown promise in wastewater treatment, bioremediation, desalination, carbon sequestration and as an alternative, renewable energy source. MFCs produces electricity via anaerobic oxidation of substrates with the subsequent extracellular electron transfer to an electrode. READ MORE

6. 4. Sound Classification in Hearing Instruments

   Author : Peter Nordqvist; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sound Classification HMM Hearing Aid; Signal processing; Signalbehandling;

   Abstract : A variety of algorithms intended for the new generation of hearing aids is presented in this thesis. The main contribution of this work is the hidden Markov model (HMM) approach to classifying listening environments. This method is efficient and robust and well suited for hearing aid applications. READ MORE

7. 5. Studies of sound generation and propagation in flow ducts

   Author : Fabrice Ducret; Mats Åbom; Andy Moorhouse; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; two-port; plane wave; HVAC system; tailpipe; exhaust system; flexible duct; pipe; reflection coefficient; impedance; flow noise; vorticity; damping; scaling laws; impedance; transmission loss; perforated plate; slit; non linearity; Acoustics; Akustik;

   Abstract : This thesis contains three papers investigating problems of interest for noise control in ducts. The first part of this thesis treats the sound propagation in rectangular ducts with flexible walls. Various experimental techniques are performed to measure the internal sound propagation and radiation to the surrounding. READ MORE