This paper reviews recent inelastic X-ray scattering investigations of simple inhomogeneous materials, such as nanoparticle suspensions in liquids. All studies reported emphasize the ability of immersed nanoparticles to dampen or attenuate acoustic waves through the hosting medium, the effect becoming even more pronounced upon freezing. Additionally, the results show that suspended nanoparticles can cause the onset of non-acoustic modes in the system. Also, the crucial role of Bayesian analysis in guiding spectral line shape modeling and interpretation is discussed. In summary, the presented results demonstrate that the simple inclusion of a sparse amount of nanoparticles profoundly influences sound propagation through a medium. This finding can inspire new avenues in the emerging field of terahertz acoustic steering and manipulation. Full article

Floor mats are commonly used to improve the impact sound performance of existing homes, but actual impact sound reductions do not consistently appear, as they depend on the test-bed conditions used to determine impact sound performance. Therefore, this study evaluated the effects of the environmental conditions of the test bed on the impact sound reduction performances of different floor mats. The Korean industrial standard KS F 2865 specifies the measurement method in the test room and sets the thickness range of the available target floor structure to bare slabs with thicknesses ranging from 120 mm to 210 mm. The evaluation method is ∆L, which is the difference in standardized impact sound levels before and after the installation of the floor finishing material. In this study, a total of eight types of floor mats were tested in four different test beds according to KS F 2865. The impact sources used were tapping, bang machines, and a rubber ball, and we used these sources to consider both light-weight and heavy-weight impact sounds. The results were derived as the impact sound reduction performance for each frequency band and a single-number quantity. The results showed that light impact sound had a similar minimum reduction characteristic of at least 38 dB, regardless of the floor structure on which the mat was installed. However, the heavy-weight impact sound showed different tendencies depending on the floor mat and the characteristics of the floor structure of the test bed when a bang machine and a rubber ball were used. In particular, the reduction achieved by the bang machine showed less than half the tendency of the reduction by the rubber ball, and the tendency of the heavy-weight impact sound was shown to be reducible depending on how the floor mat was maintained, but the reductions differed depending on the test bed. The reductions were larger in the box-type test room than in the real-life-type test room, and among the box-type test rooms, the one with a thicker bare slab showed a relatively larger reduction. In addition, the reliability of the measurement results was evaluated through a correlation analysis between the single-number quantities depending on the thicknesses of the bare slabs of the test beds. Full article

Entrepreneurs carrying out mining works under seismic hazard conditions are obliged to conduct studies in the field of engineering geophysics, including measuring, interpreting and evaluating the effects of rock mass tremors on ground vibration parameters, and thus the occurrence of harmful impacts on surface objects. However, for technical reasons, this is a difficult task to implement at all points subject to the influence of mining activities. Therefore, it becomes expedient to look for solutions that would provide greater accuracy in forecasting the distribution of ground vibration parameters. This paper proposes a method for forecasting the distribution of peak ground accelerations (PGAs) induced by mining activities, taking into account the directionality of vibration attenuation. In many cases, the explanation of the variation in the magnitude of recorded ground surface vibrations after a rock mass tremor cannot always be explained by only the variation of epicentral distances and the value of the vibration amplification factor by quaternary formations. Therefore, it is reasonable to take into account the directionality of vibration attenuation. The authors analyzed and evaluated the accuracy of predicting the distribution of ground vibration accelerations induced by mining activities, taking into account the directionality of vibration attenuation, using three models: the first, a classical model assuming isotropic vibration attenuation; the second, a model taking into account the anisotropy of vibration attenuation with elliptical isolines; the third, a model without assuming the shape of the isolines of vibration intensity parameters. For both models that took into account anisotropy of vibration attenuation, better results (more accurate descriptions of observed ground vibration accelerations) were obtained than for the model assuming isotropy. The most accurate estimates of vibration magnitude were obtained using the latter model. Full article

With the development of communications technology, surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices have become hotspots of the competitive research in the frequency band above GHz. It imposes higher requirements on the operating frequency, temperature coefficient of frequency (TCF), and electromechanical coupling coefficient (k²) of SAW devices. In this work, we reported on a novel ZnO/SiO₂/diamond-layered resonator structure and systematically investigated its propagation characteristics by using finite element methods. A comparative study and analysis of k² and acoustic velocity (v_p) for both the excited Rayleigh mode and the Sezawa mode were conducted. By selecting the appropriate ZnO piezoelectric film, SiO₂, and electrode thickness, the Sezawa mode was chosen as the main mode, effectively improving both k² and v_p. It was observed that the k² of the Sezawa mode is 7.5 times that of the excited Rayleigh mode and nearly 5 times that of piezoelectric single-crystal ZnO; v_p is 1.7 times that of the excited Rayleigh mode and nearly 1.5 times that of piezoelectric single-crystal ZnO. Furthermore, the proposed multilayer structure achieves a TCF close to 0 while maintaining a substantial k². In practical applications, increasing the thickness of SiO₂ can compensate for the device’s TCF reduction caused by the interdigital transducer (IDT). Finally, this study explored the impact of increasing the aperture width and IDT pairs on the performance of the single-port resonator, revealing the changing patterns of quality factor (Q) values. The results reported here show that the structure has great promise for the fabrication of high-frequency and low-TCF SAW devices. Full article

In order to design a low-noise water-filled pipeline system, it is necessary to obtain knowledge of the dispersion characteristics of axial propagation modes in different water-filled elastic tubes. In this work, an algorithm is developed based on the spectral method, which has previously been used to solve the dispersion of axisymmetric modes in cylindrical structures but has not yet been applied to non-axisymmetric modes. The algorithm can obtain the dispersion characteristics, modal displacement, and stress distribution of axial propagation modes in a fluid-filled elastic multi-layer tube. The algorithm behaves well both at low and ultrasonic frequencies, and it is suitable for any tube dimensions, wall thickness and layers. The results of a water-filled PMMA tube obtained using the spectral method algorithm were verified using a COMSOL simulation, while the dispersion curves of the same tube from the literature were found to be missing some low-order modes. In addition, the dispersion curves of a water-filled three-layer tube are given. The spectral method algorithm has the advantages of fast calculation speed, less computational resources consumed, accurate results, and no modal omission. Full article

The use of therapeutic ultrasounds (TUs) is widespread in both human and veterinary medicine. In fact, mechanical vibration is the simplest and purest form of vibratory energy that is applied either in physical therapies or in rehabilitation medicine. In particular, the use of low-frequency TUs to treat equine conditions is a new and evolving field. In the equine industry, osteoarthritis (OA) is one of the most challenging causes of lameness. Despite its prevalence and the advancements in its treatment, there is still no therapy whose results are completely decisive. Little is described in the literature about the use of TUs in horses’ joints, particularly regarding its use to treat OA. For these reasons, the aim of this study was to preliminarily assess the efficacy of low-frequency ultrasound in two horses with metacarpo/metatarso-phalangeal joint OA. The reduction in lameness was significant in both treated cases, pointing to the effective therapeutic action of TUs. However, to better evaluate the long-term effects in athlete horses, it is necessary to include in the research a greater number of cases and a control group. Full article