Sökning: "noise emissions"

Visar resultat 16 - 20 av 86 avhandlingar innehållade orden noise emissions.

  1. 16. On the Design of Energy Efficient Aero Engines: Some Recent Innovations

    Författare :Rickard Avellan; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbofan; aero engine; inter-turbine reheat; emissions; variable cycle; energy efficiency; propeller; NOx; MDO;

    Sammanfattning : In the light of the energy crisis of the 1970s, the old aerospace paradigm of flying higher and faster shifted towards the development of more energy efficient air transport solutions. Today, the aeronautical research and development community is more prone to search for innovative solutions, in particular since the improvement rate of change is decelerating somewhat in terms of energy efficiency, which still is far from any physical limits of aero engine and aircraft design. LÄS MER

  3. 17. The simulation of car and truck tyre vibrations, rolling resistance and rolling noise

    Författare :Carsten Hoever; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rolling resistance; rolling noise; tyres; vibrations; waveguide finite element; tyre road interac- tion; BEM; fuel efficiency; parameter study; road surface properties; numerical modelling;

    Sammanfattning : The road transportation sector places a severe burden on the environment in the form of CO2 emissions and road traffic noise. Both of these environmental prob- lems can be related to car and truck tyres. LÄS MER

  4. 18. Signal processing approaches on otoacoustic emissions

    Författare :Jun Cheng; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :otoacoustic emissions; signal processing; time-frequency representation; cochlea; outer hair cell; neonatal hearing screening; basilar membrane nonlinearity; bounce phenomenon; spectral estimation; interrelations of OAEs;

    Sammanfattning : The recent achievement on the measurement of otoacoustic emissions (OAEs) is based on a novel technical development of digital signal processing. OAEs measured in the external ear canal are normal by-products of the active process in hearing, which was discovered by Kemp (1978). LÄS MER

  5. 19. Vibration based diagnostics for analysis of combustion properties and noise emissions of IC engines

    Författare :Grover Zurita Villarroel; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk akustik; Engineering Acoustics;

    Sammanfattning : The major challenge in engine diagnostics, monitoring and optimisation is to maintain competitive fuel economy, refinement and specific power while at the same time keeping noise and exhaust emissions at acceptable levels. This requires development and integration of fuel delivery, combustion and after-treatment systems. LÄS MER

  7. 20. IC-engine intake noise predictions based on linear acoustics

    Författare :Magnus Knutsson; Mats Åbom; Antonio Torregrosa; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustics; Akustik;

    Sammanfattning : Shorter product development cycles, densely packed engine compartments and intensified noise legislation increase the need for accurate predictions of IC-engine air intake noise at early stages. The urgent focus on the increasing CO2 emissions and the efficiency of IC-engines, as well as new techniques such as homogeneous charge compression ignition (HCCI) might worsen the noise situation. LÄS MER