Initiation of Acoustic Emission in Fluid-Saturated Rock Samples under Electric Current Action

2021 ◽  
Author(s):  
Alexander Ponomarev ◽  
Vladimir Smirnov ◽  
Andrey Patonin ◽  
Tatyana Kartseva
Keyword(s):  
Acoustic Emission ◽  
Electric Current ◽  
Pore Pressure ◽  
Electrical Power ◽  
Radial Strain ◽  
Electrical Current ◽  
Sample Volume ◽  
Radial Deformation ◽  
Saturated Rock ◽  
Current Action

<p>We present the results of the laboratory studies of the activization of acoustic emission in fluid-saturated and uniaxial stressed sandstone and granite samples under the electrical current action. The experiments were carried out at the Geophysical observatory “Borok” of Schmidt Institute of Physics of the Earth (Russian Academy of Sciences) using servocontrolled press INOVA-1000 under strain control.</p><p>We recorded acoustic emission (AE), axial load, axial and radial strain of the sample and controlled the electric current flowing through the sample. The electrodes for creating an electric potential difference were mounted at the ends of the cylindrical samples. The experiments were carried out both in the presence and in the absence of a galvanic contact of the electrodes with the sample. We examined dry cores and partially saturated cores with an aqueous NaCl solution of various concentrations.</p><p>A significant increase in acoustic activity (more than several times) was found during periods of current action, as well as a decrease in activity after termination of electric action. Radial strain increases during periods of electric current flow, which indicates an increase in the sample volume. We did not find acoustic emission initiation on dry samples and on fluid-containing samples in the absence of galvanic contact of the electrodes with the samples.</p><p>The increase in the AE activity depends mainly on the electrical power and the duration of the exposure interval. The product of these parameters gives the amount of Joule heat. This indicates that the mechanism of AE initiation by electric current is of a thermal nature. Acoustic activation increases with an increase in the heat generated by the electric current passing through the sample. This makes it possible to relate the initiation of fracturing by thermal expansion of the fluid in the sample cracks and an increase in pore pressure. Found increasing of the radial deformation during the heating intervals supports this idea. Thus, the discovered phenomenon can be considered as a consequence of an unconventional way of increasing pore pressure in rocks saturated with a conducting fluid.</p><p>The effect of increasing the acoustic emission activity under electric current action is observed both in mechanically stressed samples and in free, unloaded samples.</p><p>The work was supported partly by the mega-grant program of the Russian Federation Ministry of Science and Education under the project no. 14.W03.31.0033 and partly by the state assignment of the Ministry to IPE RAS.</p>

The influence of ultrasound signal parameters on sonoluminescence light intensity

2013 ◽  
Vol 62 (4) ◽  
pp. 605-612
Author(s):  
Marek Szmechta ◽  
Tomasz Boczar ◽  
Dariusz Zmarzły
Keyword(s):  
Acoustic Emission ◽  
Acoustic Waves ◽  
Power Transformer ◽  
Electrical Power ◽  
Partial Discharges ◽  
Research Project ◽  
Insulation Systems ◽  
Secondary Phenomenon ◽  
New Research ◽  
The Relationship

Abstract Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.

Hybrid System Using Acoustic Emission and Electric Current for Fuzzy Diagnosis of Surface Wear in Gearbox Coupled to Induction Motor

2017 ◽  
Author(s):  
Leonardo José Cavalcante Vasconcelos ◽  
ARLESON KENNEDI FRANÇA DOS SANTOS ◽  
Dalton Valadares ◽  
Alexander Sena
Keyword(s):  
Acoustic Emission ◽  
Electric Current ◽  
Induction Motor ◽  
Hybrid System ◽  
Surface Wear ◽  
Fuzzy Diagnosis

scholarly journals Effect of Applied Pressure on the Electrical Resistance of Carbon Nanotube Fibers

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2106
Author(s):  
Chris J. Barnett ◽  
James D. McGettrick ◽  
Varun Shenoy Gangoli ◽  
Ewa Kazimierska ◽  
Alvin Orbaek White ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrical Resistance ◽  
Copper Wire ◽  
Applied Pressure ◽  
Radial Strain ◽  
Electrical Current ◽  
Electrical Contacts ◽  
Electrical Performance ◽  
Macro Scale ◽  
Carbon Nanotube Fibers

Carbon nanotubes (CNTs) can be spun into fibers as potential lightweight replacements for copper in electrical current transmission since lightweight CNT fibers weigh <1/6th that of an equivalently dimensioned copper wire. Experimentally, it has been shown that the electrical resistance of CNT fibers increases with longitudinal strain; however, although fibers may be under radial strain when they are compressed during crimping at contacts for use in electrical current transport, there has been no study of this relationship. Herein, we apply radial stress at the contact to a CNT fiber on both the nano- and macro-scale and measure the changes in fiber and contact resistance. We observed an increase in resistance with increasing pressure on the nanoscale as well as initially on the macro scale, which we attribute to the decreasing of axial CNT…CNT contacts. On the macro scale, the resistance then decreases with increased pressure, which we attribute to improved radial contact due to the closing of voids within the fiber bundle. X-ray photoelectron spectroscopy (XPS) and UV photoelectron spectroscopy (UPS) show that applied pressure on the fiber can damage the π–π bonding, which could also contribute to the increased resistance. As such, care must be taken when applying radial strain on CNT fibers in applications, including crimping for electrical contacts, lest they operate in an unfavorable regime with worse electrical performance.

Determination of multidirectional myocardial deformations in cats with hypertrophic cardiomyopathy by using two-dimensional speckle-tracking echocardiography

2017 ◽  
Vol 19 (12) ◽  
pp. 1283-1289 ◽  
Author(s):  
Ryohei Suzuki ◽  
Yohei Mochizuki ◽  
Hiroki Yoshimatsu ◽  
Takahiro Teshima ◽  
Hirotaka Matsumoto ◽  
...  
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Speckle Tracking ◽  
Speckle Tracking Echocardiography ◽  
Contractile Function ◽  
Radial Strain ◽  
Clinical Signs ◽  
Myocardial Deformation ◽  
Radial Deformation ◽  
Two Dimensional

Objectives Hypertrophic cardiomyopathy, a primary disorder of the myocardium, is the most common cardiac disease in cats. However, determination of myocardial deformation with two-dimensional speckle-tracking echocardiography in cats with various stages of hypertrophic cardiomyopathy has not yet been reported. This study was designed to measure quantitatively multidirectional myocardial deformations of cats with hypertrophic cardiomyopathy. Methods Thirty-two client-owned cats with hypertrophic cardiomyopathy and 14 healthy cats serving as controls were enrolled and underwent assessment of myocardial deformation (peak systolic strain and strain rate) in the longitudinal, radial and circumferential directions. Results Longitudinal and radial deformations were reduced in cats with hypertrophic cardiomyopathy, despite normal systolic function determined by conventional echocardiography. Cats with severely symptomatic hypertrophic cardiomyopathy also had lower peak systolic circumferential strain, in addition to longitudinal and radial strain. Conclusions and relevance Longitudinal and radial deformation may be helpful in the diagnosis of hypertrophic cardiomyopathy. Additionally, the lower circumferential deformation in cats with severe hypertrophic cardiomyopathy may contribute to clinical findings of decompensation, and seems to be related to severe cardiac clinical signs. Indices of multidirectional myocardial deformations by two-dimensional speckle-tracking echocardiography may be useful markers and help to distinguish between cats with hypertrophic cardiomyopathy and healthy cats. Additionally, they may provide more detailed assessment of contractile function in cats with hypertrophic cardiomyopathy.

Investigation of the effect of electric current on serrated deformation and acoustic emission in the aluminum-magnesium alloy 5056

2015 ◽  
Vol 57 (6) ◽  
pp. 1060-1066 ◽  
Author(s):  
A. A. Shibkov ◽  
A. A. Denisov ◽  
M. A. Zheltov ◽  
A. E. Zolotov ◽  
M. F. Gasanov ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Magnesium Alloy ◽  
Electric Current ◽  
Aluminum Magnesium Alloy

Research on the delamination wear properties of the pure carbon strip at the high-sliding speed with electric current

2018 ◽  
Vol 70 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Hongjuan Yang ◽  
Lin Fu ◽  
Yanhua Liu ◽  
Weiji Qian ◽  
Bo Hu
Keyword(s):  
Electric Current ◽  
High Speed ◽  
Normal Load ◽  
Copper Wire ◽  
Electrical Current ◽  
Wear Properties ◽  
Sliding Speed ◽  
Content Type ◽  
Delamination Wear ◽  
High Speed Data

Purpose This paper aims to investigate the delamination wear properties of a carbon strip in a carbon strip rubbing against a copper wire at the high-sliding speed (380 km/h) with or without electrical current. Design/methodology/approach The friction and wear properties of a carbon strip in a carbon strip rubbing against a copper wire are tested on the high-speed wear tester whose speed can reach up to 400 km/h. The test data have been collected by the high-speed data collector. The worn surfaces of the carbon strip are observed by the scanning electron microscope. Findings It was found that there was a significant increase of the delamination wear with the decrease of the normal load when the electric current is applied. The size of the flake-like peeling also increases with the decrease of normal load. The delamination wear extends gradually from the edge of the erosion pits to the surrounding area with the decrease of the normal load. However, the delamination wear never appears in the absence of electric current. It is proposed that the decreased normal load and the big electrical current are the major causes of the delamination wear of the carbon strip. Originality value The experimental test at high-sliding speed of 380 km/h was performed for the first time, and the major cause of the delamination was discovered in this paper.

scholarly journals Automotive Mechanical Vehicle Starter

2021 ◽  
Vol 2107 (1) ◽  
pp. 012021
Author(s):  
M M M. A Kader ◽  
Z B Razali ◽  
W A Mustafa ◽  
S A Saidi ◽  
A A Nagoor Gunny ◽  
...  
Keyword(s):  
Software Development ◽  
Magnetic Force ◽  
Combustion Engine ◽  
Electrical Power ◽  
Electrical Current ◽  
Mechanical Parts ◽  
Hardware Development ◽  
Start Up ◽  
Human Energy ◽  
Electrical Connections

Abstract This research is used to crank start automotive vehicle. There are many different system used in order to start-up vehicles using electric starter, in the time of battery low-power or totally drained. The purpose of this research is to help the driver to get out of this difficulty. Nowadays there are many people that have experienced such a bad moment, where they are stranded at road side due to malfunction starter in their car because of battery problem. Most of the vehicle electric starter failure is because of battery corrosion or battery undercharged. The importance of this research is to solve this problem. Starter is a vital part of the vehicle, without it no automotive vehicles able to operate. These starters will rotate an internal-combustion engine to initiate the engine’s operation under its own power. Starters also can be malfunction too due to corroded electrical connections or an undercharged battery. This system can be used to solve this problem. This system used human energy by using mechanical parts in order to produce electrical power. In order to produce electrical current, workforce will be applied by rotating the wheel that already linked by belt and from that rotations will trigger a magnetic force and it will produce an electrical current and supply it into battery. This system is divided into two development; hardware development and software development. The hardware development involved, mechanical device which is used and electrical device such as monitor. For software development, Fritzing is used to construct circuit.

scholarly journals Power Conversion and Its Efficiency in Thermoelectric Materials

Entropy ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 803 ◽  
Author(s):  
Armin Feldhoff
Keyword(s):  
Thermoelectric Material ◽  
Electric Charge ◽  
Power Factor ◽  
Short Circuit ◽  
Power Conversion ◽  
Electrical Power ◽  
Electrical Current ◽  
Open Circuit ◽  
Pump Mode ◽  
Current Curve

The basic principles of thermoelectrics rely on the coupling of entropy and electric charge. However, the long-standing dispute of energetics versus entropy has long paralysed the field. Herein, it is shown that treating entropy and electric charge in a symmetric manner enables a simple transport equation to be obtained and the power conversion and its efficiency to be deduced for a single thermoelectric material apart from a device. The material’s performance in both generator mode (thermo-electric) and entropy pump mode (electro-thermal) are discussed on a single voltage-electrical current curve, which is presented in a generalized manner by relating it to the electrically open-circuit voltage and the electrically closed-circuited electrical current. The electrical and thermal power in entropy pump mode are related to the maximum electrical power in generator mode, which depends on the material’s power factor. Particular working points on the material’s voltage-electrical current curve are deduced, namely, the electrical open circuit, electrical short circuit, maximum electrical power, maximum power conversion efficiency, and entropy conductivity inversion. Optimizing a thermoelectric material for different working points is discussed with respect to its figure-of-merit z T and power factor. The importance of the results to state-of-the-art and emerging materials is emphasized.

Empirical Modeling of Direct Electric Current Effect on Machining Cutting Force

2013 ◽  
Author(s):  
Elizabeth Jones ◽  
Joshua J. Jones ◽  
Laine Mears
Keyword(s):  
Electric Current ◽  
Shear Plane ◽  
Electrical Current ◽  
Empirical Modeling ◽  
Machining Process ◽  
Electroplastic Effect ◽  
Direct Electric Current ◽  
Orthogonal Machining ◽  
Machining Force ◽  
Force Reduction

Metallic materials can be made more ductile and be formed at lower forces through the application of electrical current during deformation, termed Electrically-Assisted Forming (EAF). The current provides a degree of resistive heating, but also facilitates deformation by direct electrical mechanisms (termed the electroplastic effect). It is envisioned that this approach, currently applied to bulk/sheet deformation, could also be used to reduce the flow stress in the deformation zone of the machining shear plane. The objective of this work is to study and model the effect of electric current on forces in machining in order to relate the force reduction to the current level and machining process parameters. To perform this, skiving tests and orthogonal machining tests are performed with varying electrical conditions. It is shown that application of electric current does reduce machining force by up to 60% under certain conditions.

Electric current and heat induced acoustic emission in cadmium sulfide

2000 ◽  
Vol 26 (11) ◽  
pp. 996-999
Author(s):  
A. A. Skvortsov ◽  
A. M. Orlov ◽  
A. S. Nasibov ◽  
O. V. Litvinenko
Keyword(s):  
Acoustic Emission ◽  
Cadmium Sulfide ◽  
Electric Current
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