On behalf of Upper Silesian Division of the Polish Acoustical Society (main organizer) and Committee of Acoustics of the Polish Academy of Sciences (co-organizer) we are pleased to announce that it is nearing the end of preparations for the conduct traditionally organized Conferences, which will take place as previously in Szczyrk. At the moment, more than 50 people have confirmed participation in Conferences. They will present more than 40 lectures and reports. 45th Winter School on Wave and Quantum Acoustics constitutes a platform for sharing the results and achievements obtained in different branches of physical acoustics (e.g. molecular acoustics, quantum acoustics, acousto-optics, magnetoacoustics, photoacoustics, acoustics of solid state etc.). Moreover, researches in some selected topics related to those mentioned above (e.g. optoelectronics, relaxation processes) will also be presented during the school. Currently, during the Conference Workshop on Acoustoelectronics and Workshop on Molecular Acoustics, Relaxation and Calorimetric Methods will be held – however, there is a possibility of organizing workshops on other subjects in the future. We would like to invite scientific centers and groups to cooperate in organizing workshops on the subjects of their interests. XLIVth Winter School on Environmental Acoustics and Vibroacoustics is the forum for all environmental and vibroacoustics fields. Particularly it concerns traffic noise, vibroacoustics of machines, room acoustics, building acoustics, noise protection and similar problems.
The 16th International Symposium on Sound Engineering and Tonmeistering (ISSET) organized by the Institute of Radioelectronics and Multimedia Technology (Warsaw University of Technology), Department of Sound Engineering (Fryderyk Chopin University of Music) and the Polish Radio, under auspicious of the Polish Section of the Audio Engineering Society was held in Warsaw on October 8-10 in 2015. The main topics of the Symposium covered mostly all domains of audio engineering, i.e. musical acoustics, noise control, signal processing, room acoustics, radio and television, multimedia, sound engineering and tonmeistering, perception and quality assessment, and many others. The extra attention has been paid for the problems of loudness of audio programs in radio and TV broadcasting. Over 60 people from different branches of audio technology participated in this Symposium and shared their knowledge and experiences during the paper sessions, technical tours, workshops and special presentations. The selection of abstracts of the papers presented at the ISSET’2015 are inserted below.
Most researchers have explored noise reduction effects based on the transfer matrix method and the boundary element method. However, maximum noise reduction of a plenum within a constrained space, which frequently occurs in engineering problems, has been neglected. Therefore, the optimum design of multi-chamber plenums becomes essential. In this paper, two kinds of multi-chamber plenums (Case I: a two-chamber plenum that is partitioned with a centre-opening baffle; Case II: a three-chamber plenum that is partitioned with two centre-opening baffles) within a fixed space are assessed. In order to speed up the assessment of optimal plenums hybridized with multiple partitioned baffles, a simplified objective function (OBJ) is established by linking the boundary element model (BEM, developed using SYSNOISE) with a polynomial neural network fit with a series of real data – input design data (baffle dimensions) and output data approximated by BEM data in advance. To assess optimal plenums, a genetic algorithm (GA) is applied. The results reveal that the maximum value of the transmission loss (TL) can be improved at the desired frequencies. Consequently, the algorithm proposed in this study can provide an efficient way to develop optimal multi-chamber plenums for industry.
Longitudinal and shear ultrasonic wave velocities were measured versus temperature in the viscosity standards of Paragon S8000S, N30000S and Cannon N2700000. The measurements were performed by the through-transmission method at the frequency of 2 MHz. Ultrasonic pulses were sent via polymethyl methacrylate (PMMA) waveguides between the tips of which a small amount of the particular standard liquid was placed. The velocities of longitudinal and shear waves were determined to depend on the viscosity of the liquid and increase with the viscosity.