The influence of a polycrystals' grain structure on elastic wave scattering is studied with analytical and numerical methods in a broad frequency range. A semi-analytical attenuation model, based on an established scattering theory, is presented. This technique accurately accounts for the grain morphology without prior assumptions on grain statistics. This is achieved by incorporating a samples' exact spatial two-point correlation function into the theory. The approach is verified by using a finite element method (FEM) to simulate P-wave propagation in 3D Voronoi crystals with equal mean grain diameter, but different grain shape uniformity. Aluminum and Inconel serve as representatives for weak and strong scattering cubic class materials for simulations and analytical calculations. It was found that the shape of the grains has a strong influence on the attenuation curve progression in the Rayleigh-stochastic transition region, which was attributed to mode conversion scattering. Comparisons between simulations and theory show excellent agreement for both materials. This demonstrates the need for accurately taking the microstructure of heterogeneous materials into account, to get precise analytical predictions for their scattering behaviour. It also demonstrates the impressive accuracy and flexibility of the scattering theory which was used.

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The impulse stimulated thermal scattering experimental technique is used for contactless in situ detection of phase transitions in thin nickel-titanium films deposited on silicon substrates. It is shown that this technique enables thedetermination of thelocal properties of the film over a fully coated wafer, in particular the thickness of the film and the temperature dependence of theYoung's modulus, and canthus beused for monitoring of the spatial distribution of thefunctional properties in films prepared by a combinatorial sputtering approach.

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The present paper focuses on corporate social responsibility in public administration. The subject of interest is the South Moravia Region and enterprises seated there. The subject of the present research includes overall awareness of the inquired enterprises about corporate social responsibility and activities of the South Moravian Region Authority related to corporate social responsibility of the institution. The research has brought conclusions testifying a certain level of knowledge of the CSR concept among enterprises, albeit on the basic level only. The awareness of socially responsible activities of the regional authority was very low and therefore further steps of this institution must be considered to improve communication of CSR activities and develop an environment for better cooperation of the public and the private sector in this area. The research was based on secondary data drawn from annual reports of the South Moravian Region Authority and on primary data obtained by questionnaire-based inquiry among 384 enterprises doing business in the South Moravia Region.

Attenuation of Rayleigh-type surface acoustic waves induced by grain-boundary scattering is studied experimentally and theoretically by an effective medium approach. A frequency domain opto-acoustic laboratory setup, capable of measuring a coherent Rayleigh wave response by emulating an ensemble average via spatial averaging, is presented. Measurements are conducted on polycrystalline aluminum at ultrasonic frequencies from 10 MHz to 130 MHz. A constant effective phase velocity of 2893 m s−1 is found below 80 MHz. The effective attenuation coefficient varies in the whole frequency range by nearly two orders of magnitude, and shows classical scattering behavior, comprising stochastic and geometric scattering regimes. A semi-analytical attenuation model is presented, valid below the geometric limit. The model incorporates the material’s spatial two-point correlation function obtained from metallurgical micrographs. Comparisons to experimentally obtained attenuation coefficients show good quantitative agreement, with differences in the frequency power-law dependence. This study attempts to elucidate microstructure induced surface acoustic wave attenuation experimentally by means of a statistical approach. The proposed method and the obtained findings contribute to the understanding of wave propagation in heterogeneous media, and promote the use of surface acoustic waves in non-destructive microstructure characterization.

In advanced functional materials, where the prestress can initialize phase transitions or other structural changes, the effect of the increasing load on an acoustic wave velocity is substantial and can provide important information on the undergoing physical phenomena. In this paper, a novel method for contactless measurements of acousto-elastic parameters is presented. The contactless arrangement, based on the concept of laser-ultrasound, enables an accurate detection of small changes of the velocities of surface acoustic waves in various directions. Because of this contactless arrangement, the changes of the sample shape during the loading do not affect the results, which can be assumed as the main source of inaccuracy for classical contact methods. The experimental device and its control system is described in detail, and its application possibilities and limits are shown on examples of shape memory alloys.

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