-
1دورية أكاديمية
المؤلفون: Kovalchuk, V. (Vitalii), Kravets, I. (Ivan), Nabochenko, O. (Olga), Onyshchenko, A. (Arthur), Fedorenko, O. (Olexander), Pentsak, A. (Andriy), Petrenko, O. (Oleksiy), Hembara, N. (Nataliya)
المصدر: Eastern-European Journal of Enterprise Technologies
مصطلحات موضوعية: земляное полотно, упругая волна удара, инерционные исследования, скорость распространения волны, плотность, земляне полотно, пружна хвиля удару, інерційні дослідження, швидкість поширення хвилі, щільність, subgrade, impact's elastic wave, wave propagation rate, Indonesia, inertial study, density
الوصف: This paper reports the analysis of the methods for estimating the technical condition of the subgrade underneath a constructed railroad track or road during its operation. The study results have proven that the issue related to monitoring and controlling high-quality compaction of a heterogeneous subgrade remains relevant and requires the construction of reliable experimental methods for assessing the subgrade degree of compaction. A procedure for determining the compaction of subgrade in the laboratory has been devised, based on inertial microcomputer technologies, which makes it possible to assess the degree of compaction of subgrade soils depending on the propagation rate of an impact's elastic waves. An experimental study has been performed into the propagation rate of elastic waves across a homogeneous subgrade made of coarse-grained sand and a heterogeneous subgrade made of coarse sand with a layer of clay in the middle of the prism. The study results established that the propagation rate of an elastic wave in a heterogeneous subgrade accepts a lower value than the rate of wave propagation in a homogeneous subgrade. Through the dynamic interpretation, by using a discriminant statistical analysis, the characteristic features have been defined in the distribution of accelerations in the body of the homogeneous and heterogeneous subgrade, depending on the degree of compaction, which would make it possible to monitor the state of the subgrade during operation. As the degree of the subgrade soil compaction affects the technical condition of roads
وصف الملف: application/pdf
-
2دورية أكاديمية
المؤلفون: Korobiichuk, V. (Valentyn), Shlapak, V. (Volodymyr), Sobolevskyi, R. (Ruslan), Sydorov, O. (Oleksandr), Shaidetska, L. (Liubov)
المصدر: Eastern-European Journal of Enterprise Technologies
مصطلحات موضوعية: labradorite, high temperatures, labradorite gloss indicators, decorativeness of natural stone, ultrasonic wave propagation, UDC 622.02, лабрадорит, высокие температуры, показатели блеска лабрадорита, декоративность природного камня, распространение ультразвуковой волны, високі температури, показники блиску лабрадориту, декоративність природного каменю, поширення ультразвукової хвилі, Indonesia
الوصف: We have experimentally investigated samples from the four fields of coarse-grained labradorite, which is extracted in Ukraine. The samples of labradorite were tested at high temperatures of 200, 300, 400, 500, 600, 700, 800, 900 °С.Red spots at the surface of samples is the result of oxidation of the metal Fe2+: at different fields of labradorite they cover a different area of the sample's surface of natural stone: it ranges from 39 to 60 %. An analysis of the polished labradorite surface after heating revealed that red inclusions are evenly distributed over the surface of labradorite samples. Oxidation of minerals, which is visually observed on all the samples of labradorite, starts at a temperature of 300 °С. One of the features in the research described in this paper is the application of digital image processing in order to quantitatively assess the Fe oxidation area (red spots) at the polished surface of labradorite samples. To a temperature of 500‒600 °С, there is a gradual increase in the oxidized area of the samples' surface. At temperatures above 700 °С, there is a sharp increase in the oxidized area at the samples' surface. In general, the oxidized spots of metals cover between 40 to 60 % of the surface of labradorite samples.When heated, the labradorite samples become 50 % brighter than the original value for indicator L in the color system Lab.A decrease in the velocity of ultrasonic wave propagation in labradorite samples occurs evenly, without surges. The reason for a decrease in the ultrasonic wave velocity is the formation of defects and cracks in labradorite samples due to an uneven thermal expansion of minerals. At a temperature of 700 °С ° or higher, there is a decrease in the velocity of ultrasound wave propagation in the samples of natural stone.At heating, there is a decrease in the indicators for gloss in all labradorite samples. In general, when labradorite was heated up to 900 °С, the samples from the Ocheretyansky deposit lost 11.21 % of their gloss, from the Neviryvsky deposit ‒ 4.03 ...
وصف الملف: application/pdf
-
3دورية أكاديمية
المؤلفون: Akmal, A. (Akmal), Rahayu, Y. (Yusnita)
المصدر: Jurnal Online Mahasiswa Fakultas Teknik Universitas Riau
مصطلحات موضوعية: Indonesia, Propagation COST 231 Multi-Wall Model, Radio Wave Propagation Simulator, Femtocell, HSDPA
الوصف: The worst network performance of “3” network provider at Building C, Faculty of Engineering has affected to the users in download / upload data from internet. Walking test measuremeat has performed and showed that average power level at each floor is -95,59 dBm. It does not meet 3GPP standard. Therefore, this paper presents the design of femtocell network for 3G indoor communication at Building C, Faculty of Engineering, University of Riau by using Radio Wave Propagation Simulator (RPS). There are two design considerations need to be calculated such as coverage area and network capacity. In terms of coverage area, four (4) Femtocell Access Points (FAPs) are required for each floor. However for netwok capacity, the FAPs are not distibuted equally for each floor, two (2) FAPs are required for 1st and 2nd floor, five (5) FAPs are required for 3rd floor. Three (3) scenarios for FAPs position are performed in this simulation; FAP is at the middle, corner, and random of ceiling. The best simulation results are obtained for random position which gives coverage area of -36.19 dBm and the lowest Signal Interference Ratio (SIR) of 1.50 dB. Both results meet the 3GPP standard.
وصف الملف: application/pdf
-
4دورية أكاديمية
المؤلفون: Mykhalevskiy, D. (Dmytro)
المصدر: Eastern-European Journal of Enterprise Technologies
مصطلحات موضوعية: a wireless channel of the 802.11 standard, signal strength distribution, multibeam wave propagation, UDC 621.391.8, беспроводной канал стандарта 802.11, распределение мощности сигнала, многолучевое распространение волн, безпровідний канал стандарту 802.11, розподіл потужності сигналу, багатопроменеве поширення хвиль, Indonesia
الوصف: We proposed a spatial method for the evaluation of signal strength at the input of the receiver for the 802.11x family of standards. For this purpose, an analysis was conducted of the basic energy characteristic for any wireless channel of the 802.11 standard and a model of the signal distribution was derived. The advantage of this method is the ease of implementation and the possibility to take into account a maximally possible number of destabilizing factors that can be relevant for a particular room.Based on the experimental evaluation of spatial distribution of strength for a typical room and for a corner placement of access point, we received a universal mathematical model and permissible limits of its change.It was established that the level of signal fluctuations indoors is affected by such basic independent components: reflected signals from the room surfaces, interference obstacles and noise. In the frequency range of 2.4 GHz for the 802.11 standard, there occurs a rather heterogeneous distribution of signals in the room with the creation of amplification and weakening regions with a difference of up to 10 dBm, and under the most difficult conditions – up to 25 dBm. It was also established that the heterogeneity of signal distribution increases proportionally to the number of reflective surfaces in a room, which is additionally enhanced by the presence of interference obstacles and noise
وصف الملف: application/pdf
-
5دورية أكاديمية
المصدر: Eastern-European Journal of Enterprise Technologies
مصطلحات موضوعية: wireless channel of the 802.11 standard, signal strength distribution, multipath wave propagation, UDC 621.391.8, беспроводной канал стандарта 802.11, распределение мощности сигнала, многолучевое распространение волн, безпровідний канал стандарту 802.11, розподіл потужності сигналу, багатопроменеве поширення хвиль, Indonesia
الوصف: A mathematical model of the spatial estimation of signal strength at the input of the receiver for the 802.11 family of standards is proposed, for a central position of the access point in a room. This model allows the assessment of signal level at any point in the room, taking into consideration the maximum possible number of factors of influence. In addition, there is a confidence interval for such a model that makes it possible to estimate the level of signal fluctuations.It was established that the level of signal fluctuations in a room is affected by such basic independent components as the signals, reflected from surfaces in the room, interference obstacles, and noise. In the frequency range of 2.4 GHz for the 802.11 standard, there occurs a rather non-uniform distribution of signals in a room with the creation of amplifying regions, as well as signal weakening, with a difference of up to 10 dbm, and under the most complicated conditions – up to 25 dbm.It was found that the level of signal fluctuations depends on the quantity of simultaneously existing destabilizing factors in the channel for premises where there is a wireless network. Taking these factors into consideration is possible through direct assessment, using the algorithm of monitoring, at a distance of two meters from the radiating antenna of AP. This is the basis for spatial method of signal strength control for any premises in real time
وصف الملف: application/pdf
-
6دورية أكاديمية
المؤلفون: Sun, B. (Bing), Xie, J. (Jie-hui), Zeng, S. (Sheng)
المصدر: Journal of Engineering and Technological Sciences
مصطلحات موضوعية: Indonesia, synchronization, stress wave propagation velocity, non-destructive testing, geotechnical engineering, collaborative length, anchoring quality, Civil Eng
الوصف: Accurate assessment of anchoring quality depends on the accuracy of assessing stress wave velocity in the anchor system. Stress wave velocity is closely related to collaborative vibration and depends on the degree of bonding between anchor body and anchorage medium. Bonding differences can be large at different ages. Based on stress wave reflection methods, non-destructive testing of anchors was performed using sensors arranged at the same cross-section of the anchor body and anchorage medium, which showed stress wave synchronization. In the early stage of filling, stress wave synchronicity was poorer between the anchor body and mortar. Therefore, the anchor should not be treated as a composite material when determining its wave velocity. Once the mortar hardens, the stress waves become more synchronous and the anchor can be regarded as a composite material. Stress wave synchronicity between the anchor body and mortar is related to mortar age and anchorage length. The anchor length required to provide stress wave synchronization between the anchor body and mortar decreases with increasing mortar age. Stress wave velocity rules were derived for different ages to provide the basis for accurately determining the stress wave velocity in the anchor.
وصف الملف: application/pdf
العلاقة: https://www.neliti.com/publications/135717/synchronicity-of-stressTest-wave-propagation-in-bolt-body-and-anchorage-medium
الإتاحة: https://www.neliti.com/publications/135717/synchronicity-of-stressTest-wave-propagation-in-bolt-body-and-anchorage-medium
-
7دورية أكاديمية
المؤلفون: Бондаренко, Ірина Олександрівна
المصدر: Eastern-European Journal of Enterprise Technologies
مصطلحات موضوعية: modeling, lifecycle, railway track deformability, wave propagation, track reliability, functional safety of track, моделирование, жизненный цикл, деформативность железнодорожного пути, распространение волн, надежность пути, функциональная безопасность пути, моделювання, життєвий цикл, деформативність залізничної колії, розповсюдження хвиль, надійність колії, функціональна безпека колії,
УДК 625.1"401.4"-047.58, Indonesia الوصف: The paper examines the modeling of the lifecycle of the railway track elements for investigating the deformation processes as the basis for the regulatory framework of the track operation to ensure the reliability of railways. To this end, the foundations of the wave propagation theory are used in describing the track and rolling stock interaction. The basic theoretical provisions and principles to describe the features of deformation operation and the calculation algorithm to determine the stress-strain state of the track are presented. Propagation of bulk and surface waves is used as exciting pulses. The requirements to the minimum length of the site under study and distance between the forces that must be considered in modeling are defined. The requirements to evaluation conditions of functional safety of the track are formed. According to the proposed model, a dynamic process, which involves the movement of the track under the effects of horizontal and vertical movements of wheels on rails for a period of time is considered.
وصف الملف: application/pdf
-
8دورية أكاديمية
المؤلفون: Доля, Сергей Николаевич
المصدر: Eastern-European Journal of Enterprise Technologies
مصطلحات موضوعية: shock wave, explosive, shock wave front, wave propagation velocity, УДК 534.1, 534.2, ударная волна, взрывчатое вещество, фронт ударной волны, скорость распространения волны, Indonesia
الوصف: To create a shock wave with a flat or concave spherical front, the explosive is formed as a spiral with a constant or variable pitch and radius of the spiral winding. Then, the propagation velocity of the blast wave becomes smaller than the propagation velocity of the detonation wave, and the velocity of the blast wave can be varied by both a pitch, and radius of the spiral winding. Such spirals are evenly arranged over the lateral surface of the cone.With the spiral winding pitch hspiral = 40 cm, winding radius r0 = 25 cm, hexogen thread diameter of 1 cm, arrangement n = 36 of spirals over the lateral surface of the cone with an apex angle Θ = 450, a cone with a base diameter Dcone = 150 m, the mass of the explosive will be about 2 tons and, at a distance r = 20 kilometers from the cone, the pressure on the blast wave front will be P> 2 atm.
وصف الملف: application/pdf
-
9دورية أكاديمية
المصدر: Jurnal Ilmu dan Teknologi Kayu Tropis
مصطلحات موضوعية: Pinus merkusii, resin tapping, sound wave propagation, Indonesia
الوصف: Non-destructive testing based on sound wave propagation has been used widely to estimate wood quality of standing trees. The aim of this study was to evaluate the characteristics of the sound wave velocity in relation to pine resin productivity and resin intercellular frequency and diameter. The samples were 72 trees consisted of 36 trees which were tapped by the quarre method and 36 other trees were tapped with addition of stimulants. The speed of sound waves propagation was measured by SylvatestDuo for radial direction and longitudinal. The tapping position was determined refering to the wind direction. The resin productivity was twice for tapping with stimulant comparing to the control. The highest resin productivity was 87.31 g per harvest for tapping with stimulant and the lowest (39.86 g per harvest) for control. Statistically, there was not significant difference in sound speed for tapped position as well as for measurement before and after tapped of both radial and longitudinal testing, as well as for the anatomical properties of both of treatments. A high positive correlation was found between resin productivity and intercellular frequency for both treatments (r>0.80), however, there was not significance correlation between resin productivity and other parameters.
وصف الملف: application/pdf
-
10دورية أكاديمية
المؤلفون: Yunita, H. (Halida), Hendriyawan, H. (H), Apriadi, D. (Dedi)
المصدر: Journal of Engineering and Technological Sciences
مصطلحات موضوعية: Indonesia, wave propagation, earthquake, soil model, nonlinear, linear equivalent
الوصف: Earthquakes can damage thousands of buildings and infrastructure as well as cause the loss of thousands of lives. During an earthquake, the damage to buildings is mostly caused by the effect of local soil conditions. Depending on the soil type, the earthquake waves propagating from the epicenter to the ground surface will result in various behaviors of the soil. Several studies have been conducted to accurately obtain the soil response during an earthquake. The soil model used must be able to characterize the stress-strain behavior of the soil during the earthquake. This paper compares equivalent linear and nonlinear soil model responses. Analysis was performed on two soil types, Site Class D and Site Class E. An equivalent linear soil model leads to a constant value of shear modulus, while in a nonlinear soil model, the shear modulus changes constantly,depending on the stress level, and shows inelastic behavior. The results from a comparison of both soil models are displayed in the form of maximum acceleration profiles and stress-strain curves.
وصف الملف: application/pdf
