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On the Efficiency of Use of Seismic Isolation in Antiseismic Construction
Tatiana Belash,
Ulugbek Begaliev,
Sagynbek Orunbaev,
Marat Abdybaliev
Issue:
Volume 3, Issue 4, December 2019
Pages:
66-74
Received:
6 March 2019
Accepted:
13 April 2019
Published:
5 November 2019
Abstract: The main issues of evaluating the efficiency of use of the seismic isolation systems as a reliable means of seismic protection of buildings and structures in seismically hazardous regions have been analysed. Specific characteristics of the most common types of seismic isolation in case of seismic load considered. It is shown that these protection systems are now becoming more common, without their respective justification. In this regard, there is a need to develop special recommendations for the use of seismic insulation in the construction of buildings and structures for various purposes. At the same time, special attention is paid to the effective conFigureuration of seismic isolation and the role of damping in it. The possibility of application of the considered protection should include: an assessment of the seismological situation of the construction area, technical and economic analysis of the choice of the type of seismic insulators, a complex of computational, theoretical and experimental studies.
Abstract: The main issues of evaluating the efficiency of use of the seismic isolation systems as a reliable means of seismic protection of buildings and structures in seismically hazardous regions have been analysed. Specific characteristics of the most common types of seismic isolation in case of seismic load considered. It is shown that these protection s...
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A Borehole Thermal Resistance Correlation for a Single Vertical DX U-Tube in Geothermal Energy Application
Issue:
Volume 3, Issue 4, December 2019
Pages:
75-83
Received:
18 October 2019
Accepted:
6 November 2019
Published:
19 November 2019
Abstract: The ground source coupled heat pump is considered as one of the most important technologies utilized in the field of sustainable energy. The borehole thermal resistance has a great impact on the total thermal resistance between the fluid that flows inside the buried U-tube and ground. This issue is related directly to the heat transfer efficiency of the ground part of the heat pump and the effective coefficient of performance of the heat pump system. The capability of the ground heat exchanger to dissipate or absorb energy to or from the ground determines the size and geometry configuration of these heat exchangers. The present research represents a model for the prediction of the borehole thermal resistance of a ground heat exchanger. The U-tube heat source or sink was replaced by a single equivalent concentric tube in the borehole possessing equal thermal resistance as that of the original U-tube heat exchanger. The model was applied for four different U-tube/borehole configurations, the test U-tubes were (9.52) mm, (12.7) mm, (15.88) mm, and (19.05) mm for a borehole to U-tube diameter ratios range of (3.94) to (7.88). The correlation showed a nonlinear dependency for the equivalent tube diameter and hence the thermal resistance of the filling on the U-tube diameter. It has also shown that for the same U-tube/borehole configuration, increasing of the U-tube legs spacing reduces the thermal resistance and approaching a minimum as the tube legs are located close to the borehole wall. Further, for the same borehole size, the thermal resistance exhibited a decrease as the U-tube size was increased and vice versa. At a borehole size of (75) mm, shank spacing to tube diameter ratio of (2), and a grout thermal conductivity of (0.78) W/m.K, the borehole total thermal resistance of the (9.52) mm U-tube size was higher than that of the (19.05) mm by (74)%. The model revealed that the grout thermal conductivity plays an important role in the thermal resistance assessment; the latter showed a decrease as the thermal conductivity increases to the highest test value of 1.9 W/m.K. The predicted thermal resistance was compared with other available correlations in the open literature and found to be consistent in the data trend and magnitudes with acceptable margin.
Abstract: The ground source coupled heat pump is considered as one of the most important technologies utilized in the field of sustainable energy. The borehole thermal resistance has a great impact on the total thermal resistance between the fluid that flows inside the buried U-tube and ground. This issue is related directly to the heat transfer efficiency o...
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Internet Security and Safety Learning via an Innovative Educational Game
Dora Puselj,
Marin Vukovic,
Mia Suhanek
Issue:
Volume 3, Issue 4, December 2019
Pages:
84-87
Received:
13 November 2019
Accepted:
23 November 2019
Published:
4 December 2019
Abstract: Nowadays, Internet safety is a very important topic in order to avoid unwanted consequences of various dangers, attacks and frauds. The Internet has over 3.5 billion users today and unfortunately Internet frauds and different types of attack have such a rapid increase that they are currently the most common form of crime. Some of the everyday possible threats to Internet users are frauds with unexpected cash winnings, frauds when buying or selling goods, false personation and personal information theft. Education and knowledge of certain internet safety measures are the first step to achieve at least a basic level of Internet safety. The aim of this paper is to make it easier and more fun to learn about Internet security and ways to protect your data. Thus, we propose an educational game for learning about the fundamentals of Internet safety through interaction with other characters and solving different problems. The proposed game is called Internet safety and it is implemented in the Unity game engine. It contains three levels and it is played by controlling the main character who solves problems and tries to find out the way to reach the next level or finish the game. The problems that need to be solved are some of the most common frauds and dangers possible to encounter while using the Internet.
Abstract: Nowadays, Internet safety is a very important topic in order to avoid unwanted consequences of various dangers, attacks and frauds. The Internet has over 3.5 billion users today and unfortunately Internet frauds and different types of attack have such a rapid increase that they are currently the most common form of crime. Some of the everyday possi...
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Acoustic Camera Design with Different Types of MEMS Microphone Arrays
Sanja Grubesa,
Jasna Stamac,
Mia Suhanek
Issue:
Volume 3, Issue 4, December 2019
Pages:
88-93
Received:
3 September 2019
Accepted:
22 October 2019
Published:
6 December 2019
Abstract: This paper investigates different approaches in designing an acoustic camera with respect to the shape of the camera as well as the number of microphones and their position on the camera. Micro electro-mechanical systems (MEMS) microphones are used in this research for the purpose of designing an acoustic camera. Several simulations implemented in MATLAB were performed for square MEMS microphone arrays, bearing in mind our primary goal, which is to design a broadband frequency range acoustic camera with MEMS microphones. In addition, a microphone array in the shape of a hemisphere was designed in order to compare all of the obtained results. Results gathered in the simulations have shown that using the square arrays and a hemispherical array enables us to construct four different broadband frequency range acoustic cameras. All of the considered versions of an acoustic camera have a respectable gain in the desired direction (i.e. the gain of the main lobe) and, in addition, a significant attenuation of side lobes. Keeping in mind the aforementioned requirements (i.e. the main lobe gain and attenuation of side lobes) it can be concluded that, from all of the considered designs, the best design is the acoustic camera with 24 MEMS microphone square array.
Abstract: This paper investigates different approaches in designing an acoustic camera with respect to the shape of the camera as well as the number of microphones and their position on the camera. Micro electro-mechanical systems (MEMS) microphones are used in this research for the purpose of designing an acoustic camera. Several simulations implemented in ...
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The Development and Analysis of Beamforming Algorithms Used for Designing an Acoustic Camera
Sanja Grubesa,
Jasna Stamac,
Ivan Krizanic,
Antonio Petosic
Issue:
Volume 3, Issue 4, December 2019
Pages:
94-102
Received:
8 November 2019
Accepted:
29 November 2019
Published:
6 December 2019
Abstract: This paper discusses the beamforming algorithms used in developing an acoustic camera which can be used for the purpose of localizing sound sources. In order to design an acoustic camera which can display results in the form of an intensity map, it is necessary to determine the beamformed signal for all the desired incident angles, i.e. for all the desired pairs of azimuth and elevation angles. For the purpose of obtaining the beamformed signal required for localization of sound sources, two beamforming algorithms, which differ in the domain in which the beamforming is performed, were developed named respectively DASt.m and DASf.m. The aforementioned algorithms are implemented in the numerical computing environment MATLAB and furthermore compared in this paper. The beamforming was carried out using both of the aforementioned algorithms for all desired azimuth and elevation angle pairs and the obtained results were compared. In order to compare these two developed beamforming algorithms measurements were conducted in an open space using a Uniform Circular Array (UCA). The utilized UCA consists of 16 identical omnidirectional microphones which form a basic circular acoustic camera. The research showed that the DASf.m algorithm gives better results than the DASt.m algorithm, especially for the intensity maps of the average of the signal.
Abstract: This paper discusses the beamforming algorithms used in developing an acoustic camera which can be used for the purpose of localizing sound sources. In order to design an acoustic camera which can display results in the form of an intensity map, it is necessary to determine the beamformed signal for all the desired incident angles, i.e. for all the...
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Ionospheric TEC Response to Geomagnetic Storms Occurred on 15-20 March 2013 and 2015 over the Eastern Africa Region
Emmanuel Daudi Sulungu,
Christian Uiso
Issue:
Volume 3, Issue 4, December 2019
Pages:
103-111
Received:
12 April 2019
Accepted:
29 May 2019
Published:
13 December 2019
Abstract: In this paper we present characteristics of the ionosphere over eastern Africa region in response to two geomagnetic storms of March 2013 and March 2015 that occurred at the same date and time but with different intensities. Ionospheric TEC has been derived from the IGS network of ground based dual-frequency GPS receivers from four stations, namely Eldoret (0.29°N, 35.29°E), Dodoma (6.19°S, 35.75°E), Malindi (2.99°S, 40.19°E) and Mtwara (10.26°S, 40.17°E) within the Eastern Africa region. The interplanetary magnetic field (IMF) Bz and corresponding Dst index, solar wind speed (Vsw) and density (Np) were used to represent the evolution of the storm events. Our results showed that, the behavior of the ionosphere over eastern Africa region during the two geomagnetic storms was similar. During both storms the main phases occurred on 17th of March. However, the main phase of the storm in 2015 had more intensity than that of 2013 but the same duration, and they were followed by a long-duration slow recovery with values that did not return to levels prior to the onset of the storm. The enhancement and reduction of TECv were observed at almost all stations at different times. The results from both storms also show that, there was a pre-reversal enhancement especially at stations that lie close to the equatorial region compared to the stations far from the equatorial region.
Abstract: In this paper we present characteristics of the ionosphere over eastern Africa region in response to two geomagnetic storms of March 2013 and March 2015 that occurred at the same date and time but with different intensities. Ionospheric TEC has been derived from the IGS network of ground based dual-frequency GPS receivers from four stations, namely...
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A Model of Public Announcement System’s Dynamics Control in Smart City Environments
Ante Grgat,
Ivan Djurek,
Mia Suhanek
Issue:
Volume 3, Issue 4, December 2019
Pages:
112-116
Received:
13 November 2019
Accepted:
2 December 2019
Published:
17 December 2019
Abstract: Nowadays, each individual is exposed to noise on a daily basis. Long exposure to noise pollution can be manifested through several health concerns such as bad mood, fatigue, insomnia, headache and loss of concentration, which can then cause reduced work ability and finally permanent hearing impairment. When considering urban areas, the most common type of noise source is traffic. Public announcement system are a vital and much needed part of every urban area and thus it should be constructed in a way that it delivers relevant information in a clear and understandable way while not disturbing the residents. Therefore, this paper proposes a model of public announcement system in urban places which aims to reduce unexpected and sudden loudness changes. The system is envisaged for public places, such as open bus stations surrounded with residential and commercial buildings. Several studies have shown that the residents of these buildings find sudden announcements very annoying and disturbing. The goal of this research is to reduce the sound level while retaining the principal loudness level. The study has shown that with the appropriate signal processing which includes a compressor and a limiter, these types of announcements can be made less annoying and disturbing for urban residents.
Abstract: Nowadays, each individual is exposed to noise on a daily basis. Long exposure to noise pollution can be manifested through several health concerns such as bad mood, fatigue, insomnia, headache and loss of concentration, which can then cause reduced work ability and finally permanent hearing impairment. When considering urban areas, the most common ...
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