Sökning: "impedance tube"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden impedance tube.

  1. 1. Assessing precision and accuracy in acoustic scattering matrix measurements

    Författare :Luck Peerlings; Hans Bodén; Susann Boij; Avraham Hirschberg; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aero-acoustics; sudden area expansion; in-duct acoustics; acoustic scattering matrix; impedance tube; uncertainty analysis; systematic errors; Vehicle and Maritime Engineering; Farkostteknik;

    Sammanfattning : Acoustic scattering matrices are used to characterize the influence of inline duct elements on the acoustic wave propagation in wave guides.When measuring the properties of these matrices, errors are always present in the results and need to be characterized to make valid statements on the correspondence between model predictions and measurements. LÄS MER

  3. 2. Moment Method Analysis of Antennas on Cylindrical Structures by Using G2DMULT and Design of Hat Fed Reflector Antennas

    Författare :Jian Yang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; G2DMULT; reflector antenna; paraboloid; dipole; base station antenna; screw heads; vertex plate; self impedance; G1DMULT; ring-shaped phase center; radiation efficiency; FDTD; cylindrical structures; V2D; ring-focus; moment method;

    Sammanfattning : This thesis deals with two aspects of research interest: moment method analysis of antennas on cylindrical structures by using G2DMULT, and design of hat fed reflector antennas. Both of them are two-dimensional (2D) structure problems, one being cylindrical and the other rotationally symmetric. LÄS MER

  4. 3. Modelling of IC-Engine Intake Noise

    Författare :Magnus Knutsson; Mats Åbom; Yves Auregán; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; IC-engine; intake noise; gas dynamics; linear source data; frequency domain; 2-port; losses; air cleaner unit; filter paper; flow; FEM; BEM; charge air cooler; narrow tube; Acoustics; Akustik;

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

  5. 4. Experimental, mild blast-induced traumatic brain injury : focus on the monoamine and galanin systems

    Författare :Lizan Kawa; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : Traumatic brain injury (TBI) is a common cause of mortality and morbidity among civilians and servicemen alike. The spectrum of TBIs encompasses mild to severe cases, with the predominate number of TBIs being mild (mTBI). Combat-related TBI inflicted by explosive blast (bTBI) is highly prevalent among military personnel. LÄS MER

  7. 5. Open and closed endotracheal suctioning. Experimental and human studies

    Författare :Sophie Lindgren; Göteborgs universitet; []
    Nyckelord :suctioning; endotracheal; closed system suctioning; monitoring; lung volume; airway pressure; lung recruitment; bronchoalveolar lavage; acute lung injury;

    Sammanfattning : Background: The practice of endotracheal suctioning of ventilator treated patients is necessary to remove secretions to prevent obstruction of the endotracheal-tracheal tube and lower airways. This very common procedure creates a large variety of heart-lung interferences. LÄS MER