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Although polystyrene materials with added graphite are actively used for the thermal insulation of buildings, there are serious problems with the detachment and warping of these materials under the influence of solar radiation. However, no systematic studies have yet been carried out on the aging of polystyrene under exposure to solar radiation. The article presents research aimed at determining changes in the thermal conductivity, compressive stress, tensile strength, and water absorption of expanded polystyrene with the addition of graphite, exposed to direct solar radiation under in situ conditions. For this purpose, expanded polystyrene (EPS) with the addition of graphite (gray EPS) and expanded polystyrene made of composite panels (gray EPS and white EPS) were exposed to direct solar radiation under in situ conditions. A third sample (reference), which was entirely white polystyrene (without the addition of graphite), was included in the tests. The results showed that expanded polystyrene with the addition of graphite degraded under the influence of direct solar radiation but improved its strength properties. Expanded polystyrene made of composite improved its compressive strength properties by nearly 11 kPa (18%), and expanded polystyrene with the addition of graphite improved its compressive strength properties by 0.4 kPa (0.5%). And the tensile strength for composite-made expanded polystyrene increased by 7 kPa (9%), and that for expanded polystyrene with the addition of graphite increased by 26 kPa (37%). At the same time, water absorption for expanded polystyrene made of composite also increased by 0.06 kg/m2 (60%), and that for expanded polystyrene with the addition of graphite increased by 0.04 kg/m2 (44%). [ABSTRACT FROM AUTHOR]

The article presents the measurement results of reverberation time, acoustic background and noise level of the tested ventilation installations in a teaching room. The research was carried out as part of the "Ventilation for schools and homes" project financed by NCBiR. The aim of the research project is to develop innovative ventilation systems dedicated to individual classrooms and apartments. The used solutions are intended to improve low air quality in schools and multi-family buildings while reducing the demand for energy necessary to heat them. For the purposes of the research, an actual-sized model room with various development options was built. The applied ventilation systems are to meet, in accordance with the imposed project guidelines, the requirements for an equivalent sound level not exceeding 40 dB. The conducted research allowed for a preliminary assessment of the acoustic quality of the room. The introduced solutions to increase the acoustic absorption of the interior allowed to obtain background acoustic levels of 20.8 dB. For the tested types of the operating ventilation, the equivalent sound level was 32.2 dB, 37 dB and 29.7 dB, respectively. [ABSTRACT FROM AUTHOR]

To fully utilize the possibilities given by the aircraft noise monitoring system, it should quickly, automatically and accurately identify whether the limit-exceeding noise event is caused by the aircraft operation. Due to the often delayed access to airport operation logs, the system should operate with minimal or no non-acoustic data. The paper proposes the architecture of an aircraft noise detection method, meeting the above requirements and attempts to assess its effectiveness. Proposed approach involves using the residual convolutional neural network for solving the task. The network operates on 1/3 octave noise input data and determines the similarity of the input sound to the aircraft noise. The accuracy of the proposed method for a single data frame using real-life measurements exceeds 95% for a frame length of at least 30 seconds. Further work is progressing, focusing mainly on improving the quality of training data and refining the hyperparameters of the network. [ABSTRACT FROM AUTHOR]

Copyright of Materiały Budowlane is the property of Wydawnictwo SIGMA-NOT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Materiały Budowlane is the property of Wydawnictwo SIGMA-NOT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents research studies on the impact of perforation of the outer lining layer of an acoustic panel used for the construction of road noise reduction devices on its absorbing properties. The research included measurements of the reverberation time in the laboratory conditions of diffusion field, on the basis of which the values of sound absorption coefficient as a function of frequency were determined. In addition, for various solutions of acoustic panels based on a corrugated fiber cement board on the top surface and on two types of mineral wool inside the panel, the αw and αp indices as well as sound absorption rating index DLαNRD were calculated. Then, computer simulations were carried out to show the influence of laboratory-determined acoustic parameters of the panels on the acoustic climate in the vicinity of a selected transport system. The key aspects of the modeling process are presented, the characteristics of the noise source and the analysis of the results are described. An important goal of traffic noise modeling is to strive to develop more friendly and sustainable material solutions that will reduce the negative effects of noise on people and the environment. [ABSTRACT FROM AUTHOR]

The article presents the assumptions of traffic intensity for a selected road section, which have been verified on the basis of measurements and data provided from General Measurement of Traffic (GPR). On this basis, simulations of noise ranges were made in the SoundPlan program. The simulations were performed for both predicted and verified traffic. Such simulations in the form of acoustic maps were used to determine the impact of the discrepancy between the assumed traffic intensity and that verified by measurements on noise range and its impact on protected areas and building development in the nearest vicinity. [ABSTRACT FROM AUTHOR]

Reverberation time in rooms depends on many factors, e.g. cubature, surface of envelopes, sound absorption coefficient of materials used for the construction of the envelopes, geometry of rooms or the distribution of sound absorbing materials. The arrangement of sound absorbing materials in rooms has an impact on the dispersion of acoustic field, yet theoretical calculation models do not take into account this impact. According to these models, regardless of the arrangement of sound absorbing materials, the reverberation time in a room will remain unchanged. The present paper investigates the above problem by means of computer simulations. For the needs of the simulation, three rooms with different dimensions were adopted, i.e. type 'p' - a cuboidal room with a square base, type 'd' - a cuboidal room (with one side of the 'p' room lengthened), type 'w' - a cuboidal room (with the height of the room lengthened 'p'). During the simulation, the way of acoustic field dispersion was being changed and its influence on the reverberation time in the rooms was being determined. The authors investigated two situations. The first one involved a non-dampened room, in which the sound absorbing material was being arranged differently. The second one involved a welldampened room, and the dispersion of sound field was analyzed depending on the location of the reflecting material.

The objective of the article is to assess acoustic insulation of a wooden floor structure between stories in a pre-war residential building. The measurements involved acoustic insulation against impact sounds and airborne sounds. The article presents the results of acoustic tests for noninsulated floors and then for floors insulated with mineral wool. First, the results of the research were analyzed in terms of single-number acoustic insulation rates. These results were compared to the standards and findings described by other researchers. Then, an analysis was carried out for the processes as a function of frequency. The conclusions described in this article allow us to assess the applied acoustic insulation system.

Thermal properties of building envelopes are often described using thermal conductivity or thermal resistance. And the opposite task involves the identification of thermal parameters of building envelopes based on the measurements of their cooling process. In this article, the authors proposed a method of identifying thermal parameters of a building envelope based on cooling measurements, using a multiple regression model for this purpose. To satisfy the research objectives, two basic experiments were carried out. The first experiment was performed in laboratory conditions. The research model was a cube of the dimensions of 1.1 m × 1.1 m × 1.1 m. The second experiment was carried out in semi-real conditions, and the used model was a small house of the dimensions of 6.0 m × 4.15 m × 5.2 m. The measurement results were also used to calibrate numerical models made in the ESP-r program. The research studies have demonstrated that the model can be used to identify thermal parameters of a building envelope. Based on the measurements and simulations, the cooling equations of the object were determined and the 95% confidence interval for the heat retention index was estimated. On that basis, using the multiple regression model, such parameters of the model as density, specific heat, and thermal conductivity were estimated. It turned out that using the Gauss–Newton approximation, we obtained the correlation of the measurement results and the analytical model with the correlation coefficient of 0.9971 (for the laboratory scale). And the multiple regression improved not only the correlation between the measurement and the analytical model, but it also allowed to obtain "almost identical" results. Similarly, promising results were obtained for the semi-real scale. [ABSTRACT FROM AUTHOR]