Gerda Vermeir

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Elemental emissions during firing in a shooting range were measured for different types of ammunition. When using Hirtenberger bullets, lead, barium, antimony and to a lesser extent copper and arsenic were the primary metal pollutants. Stationary sampling at three locations in the range did not reveal large concentration gradients. Large concentration(More)
The sound transmission loss (STL) of finite lightweight multilayered structures with thin air layers is studied in this paper. Two types of models are used to describe the vibro-acoustic behavior of these structures. Standard transfer matrix method assumes infinite layers and represents the plane wave propagation in the layers. A wave based model describes(More)
In this paper, a hybrid wave based-transfer matrix model is presented that allows for the investigation of the sound transmission through finite multilayered structures placed between two reverberant rooms. The multilayered structure may consist of an arbitrary configuration of fluid, elastic, or poro-elastic layers. The field variables (structural(More)
Simulations performed for a typical semi-infinite reticulated plastic foam saturated by air show that, at distances less than three Rayleigh wavelengths from the area of mechanical excitation by a circular source, the normal frame velocity is close to the Rayleigh pole contribution. Simulated measurements show that a good order of magnitude estimate of the(More)
The aim of this paper is to investigate the acoustic performance of sound absorbing materials through a numerical wave based prediction technique. The final goal of this work is to get insight into the acoustic behavior of a combination of sound absorbing patches. In order to address a wide frequency range, a model based on the Trefftz approach is adopted.(More)
A simple asymptotic approximation with two parameters (the plane wave reflection coefficient and a correction factor) has been derived by Brekhovskikh and Godin [Acoustics of Layered Media II. Point Sources and Bounded Beams (Springer, New York, 1992)], for the spherical field reflected by nonlocally reacting surfaces. In the present work, an expression for(More)
Statistical energy analysis (SEA) represents a framework for analyzing the high-frequency response of complex structures to mechanical or acoustical excitation [1]. In SEA, a structure is divided into subsystems and the energy #ow between these subsystems is described using coupling loss factors. In case of coupled plate subsystems, coupling loss factors(More)
A method is described for the determination of mercury in human blood serum and packed blood cells employing neutron activation analysis. Great attention was devoted to the collection and manipulation of the samples. The accuracy and precision of the method were tested by analyzing biological reference materials and by comparing the concentrations measured(More)
In building acoustics, reliable prediction methods for sound transmission loss and sound radiation are required for parameter studies, material selection and optimization studies. Today there is a lack of calculation techniques which can be use in the entire frequency range of interest (50-5000 Hz). At high frequencies, prediction methods based on(More)
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