In this paper, we demonstrate how to reduce the noise level of expanded air from pneumatic tools. Instead of a muffler, we propose the expanded collecting system, where the air expands through the pneumatic tube and expansion collector. We have elaborated a mathematical model which illustrates the dynamics of the air flow, as well as the acoustic pressure at the end of the tube. The computational results were compared with experimental data to check the air dynamics and sound pressure. Moreover, the study presents the methodology of noise measurement generated in a pneumatic screwdriver in a quiet back room and on a window-fitting stand in a production hall. In addition, we have performed noise measurements for the pneumatic screwdriver and the pneumatic screwdriver on an industrial scale. These measurements prove the noise reduction of the pneumatic tools when the expanded collecting system is used. When the expanded collecting system was applied to the screwdriver, the measured Sound Pressure Level (SPL) decreased from 87 to 80 dB(A).

This paper presents a module for monitoring the contact force between a probe for measuring vibration perception on the wrist and the skin. The module was designed for an original measuring stand for the automatic testing of the vibrotactile discrimination thresholds using the psychophysical adaptive method of 1 up–2 down with two or three interval forced choices (2IFC, 3IFC). Measurement methods were implemented in LabVIEW software. The inspiration for the project was the need to check the possibility of building a vibrating interface for transmitting information through vibrations delivered to the wrist via a bracelet. The test procedure on the wrist is not standardized; however, during its development, the recommendations of the Polish Norm–International Organization for Standardization PN-ISO 13091-1, 2006 were adopted. This standard contains methods for measuring vibration sensation thresholds on the fingertips for the assessment of neural dysfunction. The key to the repeatability of measurements seems to be the ability to continuously control the pressure of the measuring probe on the skin. This article compares two solutions for measuring the contact force along with an analysis of their accuracy and the impact of vibrations on the measured values. Moreover, the results of measurements of vibrotactile amplitude and frequency discrimination thresholds obtained on the ventral wrist at five frequencies (25, 32, 63, 125 and 250 Hz) are presented.

This paper presents the soundscape analysis of two settlements in Spitsbergen in Svalbard archipelago. The first one is the largest settlement in Spitsbergen, Longyearbyen, with population of about 2000 people. It is the administrative center of Svalbard with airport and the seat of Governor of Svalbard. The second one, Pyramiden, is Russian, coal-mining settlement closed in 1998. Since 2007 Pyramiden has become the tourist attraction with hotel and small museum. Only a few workers live there permanently. Two one-week research expeditions were organized to perform preliminary Arctic soundscape measurements. First, summer expedition during polar day and second winter-spring expedition during the transition period between the polar night and polar day. Long and short term sound pressure level measurements together with the ambisonic recordings of unique and typical sounds were made. Both qualitative assessment and quantitative analysis of the results were carried out. The identification and classification of the existing sound sources were conducted. Furthermore, noise maps of both places together with the comparative analysis were performed.

The sound reduction index R is commonly determined using standardized laboratory procedures developed primarily for full-size building elements. However, in many research and development applications, including technical enclosures, lightweight panels, modular components, and new acoustic materials, only reduced-size specimens are available. In such cases, the influence of specimen dimensions and test-opening geometry on the measured sound insulation is not yet fully understood. This study investigates the effect of specimen size and geometry on the measured sound reduction index using a dedicated small-scale coupled reverberation room stand. Measurements were performed for five materials with different mechanical and structural properties: steel, polymethyl methacrylate (PMMA), medium-density fiberboard (MDF), gypsum board, and Sylomer. Six test openings were analyzed, including three square openings, one quasi-square opening, and two rectangular openings. The results show that specimen dimensions can significantly affect the measured values of R, especially in the low-frequency range, where modal behavior, boundary conditions, and the relationship between specimen dimensions and acoustic wavelength are important. The influence of specimen size was material-dependent and was more pronounced for stiff plate-like materials than for the highly compliant Sylomer specimen. Comparisons between square and rectangular openings with similar surface areas suggest that, within the investigated range of materials, specimen geometries, and measurement conditions, specimen surface area had a greater influence on R than specimen shape, although geometry can still contribute to the measured differences. The repeatability analysis confirmed that the measurement stand is sensitive to differences related to material type, specimen dimensions, and installation conditions. The proposed methodology may be particularly useful for comparative studies of novel acoustic materials and prototype building elements when only reduced-size specimens are available during the early stages of material development. The results support the use of small coupled reverberation rooms for comparative testing and preliminary material screening, while also showing that reduced-size sound insulation measurements require careful interpretation and cannot be treated as direct substitutes for full-scale standardized tests.