This paper presents an innovative method of extinguishing of flames using a high-power acoustic extinguisher. This method allows for effective and non-invasive extinguishing of the flames. Experimental results showing the effectiveness of the fire extinguisher for different distances from the flame source and different frequencies of the acoustic wave are discussed. The paper ends with the description of the advantages, disadvantages, and limitations of the proposed fire extinguishing method.

The search for fast and environmentally safe methods of fighting fires has been a particularly important topic in recent years. Many academic centres are conducting research on the use of Deep Neural Networks to detect flames. One of the most promising is the acoustic method of extinguishing flames. In theory, an acoustic extinguisher can be applied to extinguish fires of different classes because acoustic waves pass through solids, liquids, and gases. In principle, the technology described in the article can be used to extinguish B- and C-class fires when gases or liquids are burning. Until now, the known studies have been conducted only for low-power acoustic extinguishers. Therefore, there is a need to fill a theoretical and practical gap in this respect (scientific novelty). The result of the activities is the development of new techniques for extinguishing flames with the use of Deep Neural Networks, and then extinguishing flames using a high and very high power loudspeaker applied to the acoustic extinguisher. The main aim of this paper is to present the possibilities of using Deep Neural Networks to detect fires, as well as the results of research on the extinguishing of flames with the use of square waveforms with Amplitude Modulation (AM) for several frequencies, which is also a scientific novelty, including the minimum acoustic power and sound pressure level as a function of a distance from the output of the acoustic system. On this basis, it became possible to determine the minimum power delivered to the extinguisher and the minimum sound pressure level that causes the extinguishing effect at given input parameters.

Symmetry plays a key role in the processing and analysis of not only visual but also acoustic signals in various multidisciplinary areas. New innovative and environmentally friendly methods for extinguishing flames are still being sought worldwide. One of these techniques appears to be the acoustic method. A laboratory stand was built for this purpose, which was coupled with the tested prototype of a high-power acoustic extinguisher, and then the original experiments and analyses of extinguishing effectiveness were carried out. For extinguishing, waveforms with specified parameters selected symmetrically around the frequency for which the extinguisher was designed were used. The aim of this article is to present and discuss selected measurement results concerning the possibility of flame extinguishing with the use of sinusoidal acoustic waves of low frequency (below 21 Hz), as well as with the use of frequency sweeping techniques with set parameters. Such an extinguisher can be equipped with an intelligent module so that the extinguisher may be activated automatically (without human intervention) when flames are detected. The benefits of this combination as well as the importance of image processing for flame detection are also presented in this paper. This solution, with its good fire detection and fast response, may be applicable for extinguishing firebreaks in particular.

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This article includes studies of the effects of climatic factors with signal degradation. These factors such as: humidity, temperature, fog, and snow cause the urban heat island effect. Research indicate that one of the most important climatic factors is rain [1][2][3][4][5], which can give rise to a lack of communication or interruption of communication due to the signal attenuation and noise increase. In practice, atmospheric effects are of immense importance for the links operating at frequencies above 10 GHz. At high frequencies of at least 10 GHz or more, the signal degradation due to rainfall increases further.Measurements in the region of Kielce city seem to be a good indication for system planners doing signal attenuation. Close to this city, at Psary-Kąty, there is a large satellite ground station with large parabolic antennae operated by Telekomunikacja Polska. The area of Kielce is a representative region in Poland, especially due to the central location, environment, and morphology of terrain. These factors affect the rain intensity, which exceeds by 0.01 percent the time in an average year R 0.01 (mm/h).Pol. J. Environ. Stud. Vol. 27, No. 1 (2018), 391-396 AbstractThe mechanism of propagation of electromagnetic waves can be approached in different ways. Because all radio waves behave similarly in propagation space, predicting signal degradation due to hydrometeors, abnormal refraction, and the study of selective fading can be done on the basis of measurements from the measuring position. Although some older systems (e.g., microwave beams, propagation by ionospheric refl ection) have less importance than new techniques (e.g., fi ber-optic links, wireless systems), some systems have been developed to play a meaningful role in communication (e.g., digital television broadcasting via satellites). The part of results connected with noise increase due to precipitation, rain attenuation, and total signal degradation due to rain in the frequency range between 1 and 25 GHz, which were collected at the Kielce University of Technology, as a Polish member of COST Action IC0802 -Propagation Tools and Data for Integrated Telecommunication, Navigation, and Earth Observation Systems, is presented in this article.Keywords: increase in noise due to precipitation, atmospheric attenuation, signal attenuation due to precipitation, total signal degradation, radio wave propagation

In practice, the propagation of electromagnetic waves is used in a large number of telecommunication wireless systems (e.g., satellites, radar, mobile phones, etc.). Since 2010 the Kielce University of Technology has been a member of a project focused on COST Action IC0802-Propagation Tools and Data for Integrated Telecommunication, Navigation, and Earth Observation Systems. The main scientifi c objective was to analyze the impact of weather conditions on the quality of satellite transmissions. This article presents part of the results of that project for frequencies between 26 GHz and 50 GHz. This information may be useful for ensuring the proper reception of microwave satellite signals and to minimize the risk of lack of communication due to adverse weather conditions.

Kielce University of Technology was a member of the research project COST Action IC0802 -Propagation Tools and Data for Integrated Telecommunication, Navigation, and Earth Observation Systems. Work on this project concentrated mostly on free space propagation, meteorology, and developing a coordinated set of models in order to improve the realization and design of Global Integrated Networks (including GMES and the Disaster Management and Relief System) [1][2][3][4]. This system is complicated, because it includes many types of instruments of labor (mobile and fi xed communication systems, satellite, and terrestrial communication systems, satellite navigation systems, etc.).To estimate a rain rate (mm/h) that exceeded the average year (R 0.01 ) in Poland (one-minute integration time) by 0.01% (meaning 53 minutes per year), we can use the data from the ITU-R recommendations (the last ITU-R updating characteristics of precipitation for propagation Pol. J. Environ. Stud. Vol. 27, No. 1 (2018), 383-390 AbstractKielce University of Technology was a member of the international research project COST Action IC0802 -Propagation Tools and Data for Integrated Telecommunication, Navigation, and Earth Observation Systems, whose main goal was to analyze the impact of weather conditions on the quality of wireless satellite transmissions. Measurements in the region of Kielce city seem to be a good indication for rain rate exceeding the average year in Poland by 0.01%, especially due to a central location, environment, and morphology of terrain. Near the city since 1974 at Psary-Kąty was a large satellite ground station, operated by TP SA, with up to seven large parabolic antennae. The aim of this study was to present the rain rate (mm/h) exceeding the average year (R 0.01 ) in Poland by 0.01%. The part of results connected with measurements and data acquisitions and their processing for rain rate exceeding the average year by 0.01% is presented in this article. This R 0.01 parameter for Kielce was experimentally verifi ed. Moreover, the R 0.01 parameters for the most important regions in Poland are also included in the article. On the basis of this we can predict, e.g., the availability of satellite systems within the whole territory in Poland to minimize the risk of lack or interruption of communications due to adverse weather conditions.