Sökning: "Acoustic wave absorption"

Visar resultat 6 - 9 av 9 avhandlingar innehållade orden Acoustic wave absorption.

  1. 6. Studies of sound generation and propagation in flow ducts

    Författare :Fabrice Ducret; Mats Åbom; Andy Moorhouse; KTH; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

  3. 7. Methods and techniques for precise and accurate in-duct aero-acoustic measurements : Application to the area expansion

    Författare :Luck Peerlings; Susann Boij; Hans Bodén; Yves Aurégan; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Area-expansion; Scattering matrix; Multi-microphone method; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : During the design and commissioning of combustion equipment, combustion associated instabilities are commonly encountered. These thermo-acoustic instabilities can cause undesirable noise, vibrations, local thermal and mechanical stresses in the combustor and are prominent in lean combustion. LÄS MER

  4. 8. Molecular Adsorption on Self Assembled Monolayers studied by Surface Acoustic Waves and Infrared Spectroscopy

    Författare :Lars Bertilsson; Antonio J. Ricco; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Chemical sensors based on the selective absorption of gas/vapors in polymer layers rely on molecular interactions. Details of the mechanisms involved can be obtained by studying the adsorption on well defined model organic surfaces. LÄS MER

  5. 9. Interaction between electronic and vibrational edge states in graphene

    Författare :Anton Vikström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; collective excitations; quantum acous- tics; quantum Hall effect; edge waves; graphene; solitons;

    Sammanfattning : A sheet of graphene in a magnetic field perpendicular to the sheet has electronic edge states with nonzero velocities. These edge states are localized to the edge of the sheet on the order of the magnetic length. LÄS MER