Search for dissertations about: "acoustics"

Showing result 1 - 5 of 801 swedish dissertations containing the word acoustics.

  1. 1. Acoustical properties of earplugs

    University dissertation from Engineering Acoustics, LTH, Lund University

    Author : Per Hiselius; Lund University.; Lunds universitet.; [2005]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; vibration and acoustic engineering; vacuum technology; hydraulics; Mechanical engineering; acoustic modelling; objective measurement; insertion loss; earplugs; HPE; HPD; hearing protectors; Two-Port; Four-Pole; attenuation; electro acoustics; acoustics;

    Abstract : In this study an experimental setup for measurements of high impedance objects in ducts, yielding the acoustical Two-Port properties of the object, is applied to earplugs. A frequently used experimental setup for measuring objective acoustical properties of earplugs is that of artificial ears. Great effort is spent on duplicating the human ear. READ MORE

  2. 2. Flow Duct Acoustics An LES Approach

    University dissertation from Stockholm : KTH Royal Institute of Technology

    Author : Emma Alenius; KTH.; [2012]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aero-acoustics; duct-acoustics; sound generation; acoustic scattering; acoustic-flow interaction; LES; IC-engines; orifice plate; confined jet;

    Abstract : The search for quieter internal combustion engines drives the quest for a better understanding of the acoustic properties of engine duct components. Simulations are an important tool for enhanced understanding; they give insight into the flow-acoustic interaction in components where it is difficult to perform measurements. READ MORE

  3. 3. Acoustic excitation and transmission of lightweight structures

    University dissertation from Div. Engineering Acoustics, LTH

    Author : Jonas Brunskog; Lund University.; Lunds universitet.; [2002]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; point mobility; Lamb waves; wood.; Building construction; plate excitation; cavities; near-periodicity; nearly periodic; sound insulation; timber; structural acoustics; spatial Fourier transform; resilient device; prediction model; periodic; lightweight; ISO tapping machine; airborne noise; Building acoustics; impact noise; Byggnadsteknik;

    Abstract : In order to increase our knowledge of the sound transmission and radiation processes of lightweight wall and floor structures, theoretical models are needed. Detailed models may form a valuable tool. In lightweight floor structures, impact sound insulation is perhaps the most important property to consider. READ MORE

  4. 4. Absorption Characteristics of Periodically Perforated Suspended Ceilings

    University dissertation from Engineering Acoustics, LTH, Lund University

    Author : Dag Holmberg; Lund University.; Lunds universitet.; [2003]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Building construction; Byggnadsteknik; measurement device.; flow resistance; suspended ceilings; periodically perforated facing; resonant absorbers; Room acoustics; building acoustics;

    Abstract : The sound absorption characteristics of resonant absorbers, implemented as perforated suspended inner ceilings attached with thin porous layers, are investigated. Several existing theories model the principal absorption mechanisms, but the interaction with the outer sound field influences the absorption in ways that can be modelled with new approaches. READ MORE

  5. 5. A Novel Signal Model and Estimation Method for Acoustic Doppler Current Meters

    University dissertation from Technical Acoustics, LTH, Box 118, 221 00 LUND

    Author : Thomas L Lagö; Lund University.; Lunds universitet.; [1999]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Doppler Profiler; Acoustic Doppler; Gaussian Backscattering Model; ADCM; ADCP; The Symmiktos Method; Estimation; Doppler; Current; MPCA.; Technological sciences; Teknik; Electromagnetism; optics; acoustics; Elektromagnetism; optik; akustik;

    Abstract : This thesis deals with the process of estimating underwater current from the backscattering signal transmitted from an ultrasonic transducer. The narrowband sinusoidal burst signal is Doppler-shifted due to the current, and this information is converted into current. READ MORE