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Material development in acoustic engineering plays a significant role in various applications, such as industrial noise control. It is important and relevant to consider alternative materials capable of reducing noise levels in different frequency ranges. One commonly used material in engineering structures is epoxy adhesive compositions. Favoring the use of adhesive compositions are their main characteristics, including weight reduction in structures, corrosion resistance, relatively low manufacturing costs, and high mechanical strength. This paper aims to discuss the relationship between the mechanical properties of modified epoxy adhesives, their structure, and sound absorption efficiency. The subjects of this study were specimens of an epoxy composition in the cured state. Acoustic absorption coefficients were evaluated using a dual-microphone impedance tube, and tensile, compressive, and bending strength properties were determined using a testing machine. The impact strength of the compositions was also investigated. An analysis of the structure of the adhesives in the cured state was carried out using a scanning electron microscope. The test specimens were made from Epidian 5 epoxy resin cured with a polyamide PAC curing agent. Nanobent ZR2 aluminosilicate in an amount of 1%, CaCO3 calcium carbonate in an amount of 5%, and CWZ-22 activated carbon in an amount of 20% were used as modifiers. The conducted studies revealed that the highest tensile strength was obtained for the adhesive composition with the addition of ZR2 filler. The highest compressive strength was exhibited by the adhesive composition with the addition of CWZ-22 filler. The highest flexural strength was demonstrated by the unmodified composition. For all the tested adhesive compositions, low sound absorption values were achieved, with a maximum of approximately 0.18. From the perspective of the reduction index R, it was observed that these samples performed better in reduction than in absorption. The best values were achieved in the compositions modified with CaCO3. [ABSTRACT FROM AUTHOR]

This contribution presents the results of research focused on changes in selected properties of organic-coated steel sheets in a corrosive environment of salt mist. The aim of this study was to characterise coated sheets and to analyse the influence of elevated temperature on changes in their selected properties. The methodology and experiments were chosen to simulate the accelerated ageing and to evaluate the surface of organic-coated steel sheets. During the research, the effect of artificial ageing due to increased temperature on changes in mechanical properties of coated sheets was monitored, which were determined by tensile testing according to STN EN 10002-1. The fracture surface of the test samples was analysed using a SEM. The following observations were made for the evaluation of coating by cross-cut tests according to EN ISO 2409. Corrosion tests were carried out by conducting salt spray corrosion tests according to EN ISO 9227. The test specimens were artificially sectioned using a laser beam. The results of the research experiments confirmed the assumption that the utilisation of the laser beam was convenient for the creation cross–cut test of the material. After the ageing test, only small significant changes in the basic mechanical properties of the tested materials were observed. It is necessary to take into account that there were changes in the appearance of the coating. The cross-cut test confirmed the results that the plastic-coated sheets could be utilised in salt corrosion environments. [ABSTRACT FROM AUTHOR]

Building partition structures must meet several construction and technical parameters. During the measurement of the acoustic properties of dividing structures in real conditions, surprising results are often achieved that do not correspond to the expected values. Based on this reason, the composition of nine dividing constructions were designed. The measurements were carried out under conditions that are very close to real conditions. Measurements were performed in accordance with international standards. The monitored parameters also include acoustic parameters. In this paper, the analysis of acoustic parameters of nine building dividing structures (profiles) with different compositions was performed. The individual layers were made up of common building elements. Various statistical methods, variance analysis and regression were used in the evaluation. The apparent sound reduction index values measured for different profile types for frequencies from 100 to 3150 Hz are compared using Variance Analysis (ANOVA); the assumptions for their use are verified by the Shapiro–Wilk test and Levene Test of Homogeneity of Variances. Multiple linear regression was used to identify and analyze the relationship between the independent variables and the dependent variable. The methods of regression and correlation analysis were used in determining the parameters that affect the resulting coefficient of weighted structural sound insulation. The total thickness of the profile and the number of layers were found to be statistically significant parameters. Based on these analyses, the coefficient of weighted structural sound insulation was determined. A clear-cut definition and identification of the single-number rating required would thus be instrumental in selecting the appropriate material for accomplishing the desired objectives. [ABSTRACT FROM AUTHOR]

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The contribution deals with the laser marking as one of the progressive and environment friendly technologies with utilisation in many branches of industry. Engraving and other types of laser marking of different types of materials are very actual technologies these days. Laser marking decreases the waste creation in comparison with the other classical marking technologies, which use paintings or created chips. In this experimental investigation the laser marking surface texturing of material AL99,7 according to STN 42 4003:1993-08 (STN EN 573) has been conducted. The laser marking machine TruMark 6020 and software TruTops Mark were used. Laser surface texturing after laser marking has been realised under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of engraving or annealing surfaces has been performed using scanning electron microscopy (SEM) technique. The evaluation of roughness of engraved surfaces has been realized according to STN EN ISO 4287 by using Surftest SJ 301. The aim of the contribution was to show how different laser parameters affect the surface texture and colour change of metallic materials while creating minimal waste.

In recent years, sound design has become one of the most important research topics in sound quality technology. Sound quality research, which focuses on how people perceive and evaluate sound, has gained attention especially in the automotive, transportation, and electrical appliance industries worldwide. This article focuses on the description of the methods used to evaluate sound quality and the application of an objective evaluation method. The subject of the measurements was a vehicle with a hybrid drive, and psychoacoustic parameters were measured at different vehicle speeds. With the development of noise monitoring technologies, sound quality research has gained attention, especially in the fields of automotive, transportation, industry and electrical appliances worldwide. The concept of product sound was strongly influenced by the automotive industry's need to design the sounds generated by vehicles to give the impression of high quality in every respect. The sounds generated by the car indicate certain aspects of how it works and these positive sounds are enhanced to compete with other car brands. [ABSTRACT FROM AUTHOR]

Various interior non–metal materials contained in the automobiles, mainly such as textiles, synthetic textiles, leather, synthetic leather and foam– based materials, are suitable for the production of sound and thermal insulation products. The presented contribution deals with the proposal of reusing and recycling of these components for the utilization of these non–metal materials for the production of new products, which, due to their sound and thermal insulation properties, will be widely applicable in various fields of industry as civil engineering, transport. [ABSTRACT FROM AUTHOR]

One of the practical applications of psychoacoustics is the evaluation of sound quality. Sound quality assessment has been the domain of the music and audio industry for years. Driving comfort in cars is becoming an increasingly important demand of customers. In addition to many other properties, emphasis is also placed on oscillatory and vibrational acoustic properties - the so-called HVP (Noise, Vibration, Transmission) characteristics of the vehicle. The article is focused on the assessment of psychoacoustic parameters in the interior of selected types of vehicles. Measurements were made on vehicles with gasoline, diesel and electric engines. Five psychoacoustic parameters were measured and a psychoacoustic head was used for the measurement. The measurements were carried out at different speeds and the measured values were processed and evaluated. [ABSTRACT FROM AUTHOR]

Energy production in industrial communities consume a main part of primary raw materials and it is one of the sources of ecologicall impact. Electric power plants and warm produce plants are mostly important investment consuming establishments with a long time of return, what stress along with the economical, predictional, logistical and environmental decision making aspect of their allocating. Already input of the mentioned aspects along with the price movement after the energy depression motivate a formation of new conception of combinated so-called items, which are able to use the energetic potential of fuels with a higher concurrent efficiency and, on the other hand, can reduce ecologic impacts of fossil combustion.

Èlánok vychádza z poznatkov, získaných rieením rezortnej výskumnej úlohy PO1-125-823 "Manipulátory pre hlbinné bane", ktorý je návrhom autorov. Pozornos sa sústreïuje na súèas-ný stav v zavádzaní manipulátorov pre hlbinné bane, uvádzajú sa kritériá a podmienky ich nasadzovania. Príspevok prezentuje manipulátor, urèený pre automatizáciu opráv banských vozíkov priamo v podzemí. Navrhnuté rieenie je autorsky chránené. Struène sú charakterizované problémy, ale aj monosti, ktoré robotizácia ponúka baníctvu.

In the present age, the acoustic properties of materials play an increasingly important role in the design and solution of passive control of unwanted noise in several industries. Knowing these properties before their actual application in practice is extremely important. There are various methods and approaches to evaluation and various ways to examine these properties. For this research, we selected 9 types of materials, which were evaluated in terms of the analysed acoustic properties at different thicknesses (2 ~ 60 mm) with diameters of 30 and 60 mm as separate single-layer, but also as a two-layer and three-layer sandwich of materials (a total of 61 variants of arrangement). The analysis was performed on the basis of measurements for which an impedance tube was used, and the analysed acoustic property was the sound absorption coefficient α (-). Measurements were performed in the frequency range from 100 Hz to 6300 Hz. We compared the results of measurement in terms of changes in the acoustic properties with varying thicknesses and frequency range. [ABSTRACT FROM AUTHOR]

In spite of existing European and national legislation aimed at noise abatement, public interest and concern about noise are high. The EU Directive 70/157/EEC [4] for setting and controlling environmental noise is aimed at creating less noisy and more pleasant environment for European residents within "Sustainable Development in Europe". The authors are presenting a methodology for measuring selected acoustic descriptors (sound absorption coefficient and sound transmission loss) for acoustic materials, which are currently in process of development. Emphasis is put on sandwich structures of absorbers. Verification results of the proposed methodology are presented. [ABSTRACT FROM AUTHOR]