scholarly journals CORRECTION OF THE METHOD FOR MEASURING THE AMPLITUDES OF THE CURRENT OF THE IMPULSE ALONG THE LONG EARTH ELECTRODE

2021 ◽  
pp. 79-85
Author(s):  
Viktor Nizhevsky ◽  
Sergey Berezka ◽  
Olena Fedoseenko ◽  
Ilia Nizhevsky
Keyword(s):  
Experimental Studies ◽  
Pulse Amplitude ◽  
Practical Reasons ◽  
Manufacturing Cost ◽  
Technical Equipment ◽  
Improved Method ◽  
Power Sources ◽  
Current Impulse ◽  
Lightning Current ◽  
Earth Electrode

An improved method for measuring the amplitude reduction of the lightning current impulse as it flows from the beginning to the end of long horizontal earthing arrangement using ferromagnetic recorders has been substantiated. Two existing methods of pulse amplitude measurements at high voltages, the magnetic recording method and the method using a shunt, are used in justification. It is noted that in a number of cases it becomes necessary to determine the decrease in the pulse amplitude as it flows on a long object. This leads to the need to develop a method for performing such measurements. As an example, a long horizontal earth electrode was investigated when a lightning current pulse moves on it. Based on experimental studies in natural conditions, an improved method for measuring the decrease in the amplitude of the lightning current impulse along a long earth electrode is proposed. The proposed method has a measurement error not exceeding 10 %, and allows simultaneous measurements of the amplitude of the current strength at given points of the object, which can amount to tens or even hundreds. This method is implemented in a simple design and has an affordable manufacturing cost. The results of the experiments performed make it possible to recommend the corrected measurement method for practical use on existing electrical installations. The use of ferromagnetic recorders for recording and measuring the lightning current in areas of complex earthing arrangements is relevant for practical reasons, which include the possibility of measuring during a long wait and long-term storage of measurement results, does not require additional power sources and provides the possibility of synchronous measurements at various points of the grounding device. An important feature of the method is safety for technical equipment and personnel.

scholarly journals Experimental study on the thermal behaviour of fire exposed slim-floor beams

2018 ◽  
Author(s):  
Vicente Albero ◽  
Ana Espinós ◽  
Enrique Serra ◽  
Manuel L. Romero ◽  
Antonio Hospitaler
Keyword(s):  
Cross Section ◽  
Thermal Behaviour ◽  
Thermal Model ◽  
Elevated Temperatures ◽  
Experimental Studies ◽  
Composite Beams ◽  
Technical Equipment ◽  
Design Code ◽  
Special Configuration ◽  
The Cross

Steel-concrete composite beams embedded in floors (slim-floors) offer various advantages such as the floor thickness reduction or the ease of installation of under-floor technical equipment. However, this typology presents important differences in terms of thermal behaviour, as compared to other composite beams, when exposed to elevated temperatures. These differences are due to their special configuration, being totally contained within the concrete floor depth. Moreover, the current European fire design code for composite steel-concrete structures (EN 1994-1-2) does not provide any simplified thermal model to evaluate the temperature evolution of each slim-floor part during a fire. Additionally, only a few experimental studies can be found which may help understand the thermal behaviour of these composite beams. This paper presents an experimental investigation on the thermal behaviour of slim-floor beams. Electrical radiative panels were used in the test setup to produce the thermal heating. The thermal gap between the lower flange of the steel profile and the bottom steel plate was studied, being found to be one of the most influential elements over the cross-section temperature gradient. The experimental campaign was developed by varying the cross-section configuration in order to evaluate the influence of this parameter over the slim-floor thermal behavior. Finally, the experiments carried out were used to develop and calibrate a finite element thermal model which may help in further research on the thermal behaviour of slim-floor composite beams.

Diagnostics of Advanced Power Intensive Power Sources Based on the Acoustic Spectroscopy Method

2021 ◽  
pp. 121-127
Author(s):  
E.M. Petrenko ◽  
V.A. Semenova
Keyword(s):  
High Reliability ◽  
Methodological Approach ◽  
Spectral Characteristics ◽  
Experimental Studies ◽  
Mechanical Action ◽  
Mean Value ◽  
Spectroscopy Method ◽  
Power Sources ◽  
Acoustic Spectroscopy ◽  
Noise Diagnostics

Objective of this article is to develop a method for lithium chemical current sources diagnostics, which would ensure high reliability in assessing their technical state (primarily, the discharge degree) close to potentially achievable introduction of the acoustic spectroscopy method. Today, microcalorimetric studies and methods of impedance and noise spectroscopy make it possible to predict the lithium chemical current sources service life. However, implementation of the microcalorimetric studies result requires a lot of time accompanied by using stationary and large-size equipment, which is practically impossible in the autonomous conditions. Application of the impedance spectroscopy method provides satisfactory results only with high degrees of discharge. In the range of 0--30 %, it is very difficult to determine the discharge degree, since noticeable alteration in the correlate within its deviation from the mean value is missing. In this regard, it is proposed in order to provide diagnostics of the lithium chemical current sources in the region of initial degrees of discharge to introduce the noise diagnostics method. In order to increase reliability of the diagnostic estimates, it is advisable to use acoustic spectroscopy as a physically independent method in diagnosing the state of lithium chemical current sources. Results of the preliminary measurements analysis confirm the prospects of using the acoustic spectroscopy method in assessing the current state of primary lithium chemical current sources. Experimental studies of the lithium chemical current sources response to acoustic (mechanical) action made it possible to determine a set of parameters characterizing the proposed methodological approach. This provided a possibility to search for correlation dependences of the lithium chemical current sources spectral characteristics on the degree of their discharge. This makes it possible to use the method of acoustic spectroscopy in prompt and reliable diagnostics of the primary current sources in the region of low discharge degrees

scholarly journals Self-oscillations at the frequency of subharmonics in nonlinear electric chains and systems

2019 ◽  
Vol 139 ◽  
pp. 01054 ◽  
Author(s):  
M.I. Ibadullaev ◽  
A.N. Tovbaev ◽  
A.Zh. Esenbekov
Keyword(s):  
Single Phase ◽  
Experimental Studies ◽  
Power Lines ◽  
Equivalent Model ◽  
Critical Parameters ◽  
Steady State Mode ◽  
Power Sources ◽  
Electric Circuits ◽  
Three Phase ◽  
Extensive Class

It is known that the occurrence and existence of autoparametric oscillations (AIC) at the subharmonic frequency (GHC) in power lines (power lines) and in power supply systems is extremely undesirable, since they cause ferroresonant overvoltages at different frequencies. At the same time, there is an extensive class of nonlinear electric circuits in which the excitation of the AIC at the frequency of the SGC forms the basis of frequency-converting devices serving as secondary power sources. It is shown that single-phase-three-phase nonlinear systems are, to one degree or another, equivalent circuits of power lines, the main elements of which are: longitudinal compensation capacitors, transverse compensation reactors, and transformers with non-linear characteristics. The regularities of the excitation of the GCC at the frequency (ω / 3) of the power lines were studied, theoretical and experimental studies of the equivalent model of single-phase-three-phase circuits with nonlinear inductance were carried out. For a theoretical analysis of the steady-state mode of SGK at a frequency (ω / 3) with inductive coupling, the frequency- energy approach is used. The conditions of existence and critical parameters of the circuit are determined, and the mechanism of the appearance of the SGC at the frequency (ω / 3) is also studied.

scholarly journals The influence of technogenic transformations of the geological environment in the extraction of minerals on the seismic activity of the earth's crust in mining regions

2018 ◽  
pp. 57-67
Author(s):  
A.P. Butolin ◽  
T.V. Chekushina ◽  
V. I. Lyashenko ◽  
V.A. Tscherba ◽  
K. A. Vorobiev
Keyword(s):  
Seismic Activity ◽  
Oil And Gas ◽  
Experimental Studies ◽  
Seismic Monitoring ◽  
Earth’S Crust ◽  
Technical Equipment ◽  
Geological Environment ◽  
Engineering Structures ◽  
Earth's Crust ◽  
Mining Regions

Purpose. Assess the influence of technogenic transformations of the geological environment in the extraction of minerals on the seismic activity of the earth's crust in mining regions, taking into account the technogenic impact on the natural environment of geodynamic processes in the upper layers of the lithosphere, where active production of oil and gas is being carried out on the basis of automated systems and new generation technical equipment, developed by experts from leading scientific centers of the world. Research methodology. Field and experimental studies, transformations of the physicochemical characteristics of groundwater, changes in the collecting properties of operational blocks and layers of sedimentary, igneous and metamorphic rocks using standard and new methods were used. Results. It is established that monitoring seismic events in the network of seismic stations when selecting technological modes of production, planning the construction and operation of engineering structures, reducing the likelihood of emergency situations and informing the public about seismic activity in the region and will allow to take seismicity into account. Scientific novelty. Data of geological development, its structure and tectonic regime within the Ural region are systematized taking into account the types and degree of man-made loads on geological structures, injection of adjacent water layers and toxic industrial wastewater into deeply absorbing layers of carbonate rocks. The possibility of assessing further changes in the geological environment within the region under study is proved based on the current state of technogenic and geodynamic interaction. Practical value. The introduction of seismic monitoring in the oil and gas industry and the mining industry allows real-time study and analysis of the degree of change in the stress-strain state of the geological environment of the region. Key words: deposits, oil, gas, ore, geological environment, technogenic load, mining regions, seismic monitoring.

scholarly journals Wireless Wearable Electrochemical Sensors: A Review

2021 ◽  
Vol 8 (10Years) ◽  
Author(s):  
Thais Alves ◽  
Patricia Deroco ◽  
Dagwin Wachholz Junior ◽  
Lourenço Vidotto ◽  
Lauro Kubota
Keyword(s):  
Chemical Sensor ◽  
New Technologies ◽  
Electrochemical Sensors ◽  
Wearable Sensors ◽  
High Sensitivity ◽  
Fast Response ◽  
Manufacturing Cost ◽  
Time Data ◽  
Power Sources ◽  
Home Based

The demand for wearable sensors has been grown rapidly over the past few years, mainly those related to monitor health, fitness and their surroundings. Consequently, wearable chemical sensing has become a crucial appliance area for wireless sensors and has proved to be a very challenging and multidisciplinary area. The great advantage of coupling wireless communication to different types of wearable sensors is the enhancement of the sensor’s scope for remote and resource-limited settings with the possibility of obtaining real-time data acquisition and application in different areas like homeland defense, home-based healthcare, and food logistics. Being the electrochemical sensors considered attractive and promising to use in the wireless chemical sensor field, due to its features such as simple structure, the possibility of miniaturization, comfort, simplicity of operation, high sensitivity, fast response, relatively low energy consumption and low manufacturing cost. Furthermore, wearable electrochemical sensors enable obtaining insights into individuals' health status through the noninvasive monitoring of clinically relevant biomarkers in different biofluids without complex sampling, manipulation and treatment steps. In this review, we present the main advances in technologies used in the development of fully integrated wireless wearable electrochemical devices, such as communication protocols, data collection and privacy concerns and power sources. We also discuss in a critical way the main challenges, trends, strategies and new technologies that will drive this research line in the future. Lastly, we highlight the progress in the last few years in healthcare, sports, security and defense, and forensic applications.

scholarly journals PURIFICATION OF ALKALINE ELECTROLYTE FROM DISSOLVED REACTION PRODUCTS DURING WORK OF THE AIR-ALUMINUM CHEMICAL CURRENT SOURCE

2019 ◽  
Vol 16 (33) ◽  
pp. 337-350
Author(s):  
N. S. OKOROKOVA ◽  
A. V. PERCHENOK ◽  
E. V. SUVOROVA ◽  
A. A. FARMAKOVSKAYA
Keyword(s):  
Current Source ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Aluminum Concentration ◽  
Alkaline Electrolyte ◽  
Reaction Products ◽  
Chemical Current Source ◽  
Power Sources ◽  
Stage Of Development ◽  
Process Solutions

The relevance of the article is based on the fact that the state of work on the creation of power sources (PS) with AA chemical current sources (CCS) is at the stage of development and testing of prototypes. The purpose of this article is to calculate dimensions of the electrolyte circuit and the crystallizer. There were experimental studies of the decomposition kinetics of the process solutions of potassium aluminate in the range of temperatures and compositions corresponding to operating conditions with PS AA CCS for various purposes. This study presents the results of applying various methods of cleaning an alkaline electrolyte from dissolved reaction products formed during the operation of an air-aluminum (AA) chemical current source (CCS). The kinetic parameters of decomposition of aluminate solutions were experimentally determined, depending on temperature, the concentration of dissolved aluminum, concentration of initial aluminum hydroxide and the size of the first surface. The dimensions of the electrolyte purification systems from dissolved reaction products — electrolyte circuit and crystallizer — were calculated, which significantly increased the time continuous operation of power sources (PS) based on AA CCS. It was demonstrated that for a 100 W power supply, the crystallizer volume should be 1.3 l with initial concentration of 20 % of mass. The mass of water consumed during the operation of the PS for 6 hours is 1.4 kg.

scholarly journals A Method for Manufacturing Flexible Microfluidic Chip Based on Soluble Material

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Junyao Wang ◽  
Xingyu Chen ◽  
Huan Liu ◽  
Gongchen Sun ◽  
Yunpeng Li ◽  
...  
Keyword(s):  
3D Printing ◽  
Dissolution Rate ◽  
Microfluidic Chip ◽  
Experimental Studies ◽  
Bonding Process ◽  
Manufacturing Cost ◽  
Processing Conditions ◽  
Microfluidic Chips ◽  
Novel Method ◽  
Soluble Material

In this paper, a novel method for manufacturing flexible microfluidic chips without bonding process is proposed, which combines 3D printing technology and material dissolution technology. The manufacturing process of the microfluidic chip is as follows: a soluble HIPS mold with a preset shape is manufactured by 3D printing and placed in a molten PDMS solution for solidification. Soak in the limonene material to dissolve the mold and form a microchannel in the cured PDMS. Experimental studies have shown that the temperature and concentration of the limonene solution have an important effect on the dissolution rate. A 0.62 cm3 HIPS mold has the fastest dissolution rate at 100°C and 50% concentration. The proposed method provided a new idea for fabricating flexible microfluidic chip. Compared to bonding process, it has the characteristics of not relying on complicated processing conditions and low manufacturing cost.

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