The purpose of this research is to investigate the acoustic properties of natural fibres and compare them with the values achieved by common insulation materials used in the construction of buildings. Three materials based on biomass were used for testing, namely cork, hemp and fibreboard. From the group of conventional materials, mineral wool, propylat and polyurethane foam were selected. For the purpose of determining the values of the sound absorption coefficient (α), the absorber specimens were tested using the impedance tube and two microphones method, according to standard ISO 10534-2. The measurement was performed for thicknesses of 20, 40, 60, 80 and 100 mm. The highest sound absorption of all materials was measured with a hemp sample at a frequency of 2000 Hz (α = 0.99) and a thickness of 20 mm. The lowest performance was achieved by cork at the same thickness and frequency of 100 Hz (α = 0.02). Among biomass materials, hemp dominated in the entire frequency range and at all thicknesses. The lowest values were for cork, from 160 to 500 Hz with a tendency to exceed the values of the fibreboard sample. Among conventional materials, mineral wool achieved the best results, while the lowest values were recorded for propylat with the occasional exception of the highest frequencies from 1600 to 2500 Hz.

Industry and industrial complexes are often located in the proximity of people’s homes. One of the negative effects of industry is noise emissions into the surrounding environment. With the increasing concentration of the human population and the increase in industrial production, more and more people are exposed to the negative effects of noise. This article discusses a comprehensive approach to reducing noise emissions from industrial operations, and the subsequent impacts on surrounding villages and human health. The first step of the whole process is to understand the current state of the acoustic situation in industrial operation and in the nearby villages, an important part of which is the identification and localization of dominant noise sources. For this purpose, a unique noise visualization tool was used, namely, an acoustic camera. The next important step is to propose a technical solution and measures to reduce the noise of the individual source. Consequently, it is necessary to create a mathematical model, i.e., noise maps, in order to verify whether the proposed measures will be sufficient. Once the proposed measures have been implemented, verification of the effectiveness of these measures needs to be carried out through repeated noise measurements in nearby villages and also on the site of the industrial installation. The above procedure was applied to the operation of a wastewater treatment plant that was causing noise exceeding the permissible levels in the surrounding villages. The application of this approach, the implementation of the proposed measures, and the subsequent verification confirmed a significant reduction in the noise levels in the affected villages, and the measures implemented were assessed as highly effective.

This article not only offers a chronological overview of the development of occupational medicine, but also offers a summary of occupational diseases recommended by the ILO and legislative decisions that have influenced how we approach assessment today. We consider that these areas form a whole in which they cannot function without each other and they would lose their relevance if the system was collapsed. By excluding even one part of it, we would find ourselves at the beginning of the era of occupational medicine, and a large number of employees would once again be exposed to conditions that previously led to considerable illness and mortality of employees. The article also examines legislation and the development of occupational diseases in Slovakia in the period 1997–2019. Using basic statistical methods and time series, a trend model for the time series of the development of the number of occupational diseases over the last 20 years is created. The modeling also includes a forecast for the development of the number of occupational diseases for the next 5 years. The model created shows a favorable, decreasing trend in the number of occupational diseases in Slovakia.

The application of recycled materials from the automotive industry in the field of the construction industry is a suitable alternative application for these materials and the use of their acoustic and thermal insulation properties. The output of recycling is granular, or chopped materials that can be used as a substitute for conventional materials. One of the important features of building materials is their acoustic properties. The measurement and evaluation of acoustic properties is carried out using an impedance tube as equipment. Measuring compact materials is quite simple and requires the preparation of a sample. Measuring the acoustic properties of granular bulk materials is more complicated and requires the development and production of a special test cartridge. Recycled bulk materials from the automotive industry such as rubber granules and chopped textiles can be applied as fillings for dividing structures. The aim of this paper was to assess the acoustic properties of different fractions of recycled rubber granules and textile chopped material and to compare acoustic properties with compact rubber and textile panels. To evaluate and compare sound absorption coefficient (α) and sound transmission loss (R) parameters, we used basic statistical methods and hypothesis testing methods. The production of compact panels is quite expensive since it is necessary to use special synthetic binders in production, and the content of these substances can also have negative effects on the environment. Based on the results of measuring the acoustic properties of bulk recycled materials and comparing them with compact materials, we can conclude that bulk recycled rubber and textile materials have very good values for their acoustic properties, which enables them to be used in several areas of industry.

The paper describes a specific design of the sound insulating enclosure of the vibrating sorter. Recycling aspects have also been taken into account when designing the enclosure, because recycled foam has been applied as a sound-absorbing material. Acoustic camera was used to measure, analyze,...

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient α_n, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.