Search for dissertations about: "mid-frequency"

Showing result 1 - 5 of 9 swedish dissertations containing the word mid-frequency.

  2. 1. Hybrid and Dynamic Substructuring Methods for Energy Flow Analysis

    Author : Anders Wilson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fractional derivatives; structural modeling; mid-frequency; finite element method FEM; vibro-acoustics; statistical energy analysis SEA; dynamic substructuring; hybrid analysis; viscoelasticity;

    Abstract : Modeling techniques and solution tools to analyze the dynamic and vibro-acoustic behavior of complex built-up structures are matters of increasing interest, especially for thin walled structures as in transportation vehicles, such as automobiles, trucks, trains and aircraft. In structures like these, the reduction of cost, weight, sound and vibration levels are primary issues for research and development. READ MORE

  4. 2. Hearing in menopausal women and in women with Turner syndrome : a model for hearing matured in an estrogen-deficient environment

    Author : Christina Forshell Hederstierna; Karolinska Institutet; Karolinska Institutet; []
    Keywords : ;

    Abstract : Epidemiological studies have shown that women have better high-frequency hearing than men in virtually all age groups, regardless of noise-exposure, and that agerelated hearing decline starts after age 30 in men but not until after the age of 50 in women. This coincides with the menopausal transition in most women, thus leading us to hypothesize that the menopause triggers auditory deterioration. READ MORE

  5. 3. Clinical and Genetic Studies of Hearing Impairment

    Author : Carina Frykholm; Ulla Friberg; Hans-Christian Larsen; Niklas Dahl; Marie-Louise Bondeson; Lisbeth Tranebjaerg; Uppsala universitet; []
    Keywords : Otorhinolaryngology; NF2; array-CGH; Meniere’s disease; PIK3C2G; X-linked; progressive; hearing impairment; Otorhinolaryngologi;

    Abstract : Monogenic disorders offer a possibility for studies of genetic disturbances in hearing impairment—a knowledge which could be essential for development of future treatment options. In this thesis, the underlying genetic disturbances in neurofibromatosis 2 (NF2) and familial Meniere’s disease (FMD) were evaluated, and familial X-linked hearing impairment was described from a clinical point of view. READ MORE

  6. 4. Experimental and Numerical Multi-port Eduction for Duct Acoustics

    Author : Stefan Sack; Abom Mats; Phillip Joseph; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; acoustics; aeroacoustics; flowacoustics; multi-ports; orifice; silencer; experiment; numeric; IDDES; LNSE; optimization; test rig; Monte Carlo; Teknisk mekanik; Engineering Mechanics;

    Abstract : Sound generation and propagation in circular ducts for frequencies beyond the cut-on frequencies of several higher order acoustic modes is investigated. To achieve this, experimental and numerical set-ups are designed and used to research aeroacoustic interactions between in-duct components and to conceive noise mitigation strategies. READ MORE

  7. 5. Investigation of acoustic source characterisation and installation effects for small axial fans

    Author : Per-Olof Berglund; KTH; []
    Keywords : axial fan; airborne sound; source characterisation; transmission path analysis; in-duct. Spherical harmonics;

    Abstract : Fans are often used in equipment such as home appliances andelectronic equipment where the margin of profit is small butcustomers demands on a low noise level are high. Therefore,methods for predicting the noise emitted by an applicationincluding one or several fans are desirable in order toimprove, accelerate and reduce the cost of low-noise design. READ MORE