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A combination of the peroxymonosulfate (PMS) electro-activation process and the electro-oxidation process driven by a pulsed electric field (PEF) was used to degrade sulfadiazine (SND) wastewater. Mass transfer is the limiting step of electrochemical processes. The PEF could enhance mass transfer efficiency by reducing the polarization effect and increasing the instantaneous limiting current compared with the constant electric field (CEF), which could benefit the electro-generation of active radicals. The degradation rate of SND after 2 h was 73.08%. The experiments investigated the effects of operating parameters of pulsed power supply, PMS dosage, pH value and electrode inter distance on the degradation rate of SND. The predicted response value of single-factor performance experiments was obtained as 72.26% after 2 h, which was basically consistent with the experimental value. According to the quenching experiments and EPR tests, both SO4•− and •OH were present in the electrochemical processes. The generation of active species were significantly greater in the PEF system than that in the CEF system. Moreover, four kinds of intermediate products were detected during the degradation by LC-MS. This paper presents a new aspect for electrochemical degradation of sulfonamide antibiotics.

Understanding the discharge characteristics as well as the detectability of metal particles in the GIS will be helpful in improving its safety and reliability. In this paper, the pulse current and UHF signals generated by PDs of metal particles of different lengths at different positions on a real spacer surface were studied. The PD characteristics and detectability of the metal particles on the spacer surface were obtained while the detection limitation was also discussed. It is found that under PD test condition, the apparent charge of the PDs is less than 1 pC for particles smaller than 5 mm, and the conventional PD detection method have limitations in detecting these small defects. Under operation condition, only the apparent charge of particles larger than 8 mm can exceed 1 pC, which means it is difficult to detect the particles smaller than 8 mm in field. However, even the 5-mm-long particle will be harmful to the GIS. Meanwhile, it is also been found that the detection sensitivity also has a great influence on the judgement of PD severity. This study is of great interest for understanding the PD characteristics, discharge levels, and detectability of small metal particles on spacer surface

SiCp/AZ91D magnesium matrix composites with 30% SiCp were successfully prepared by pulsed current melting in this work. Then, the influences of the pulse current on the microstructure, phase composition, and heterogeneous nucleation of the experimental materials were analyzed in detail. The results show that the grain size of both the solidification matrix structure and SiC reinforcement are refined by pulse current treatment, and the refining effect is gradually more obvious with an increase in the pulse current peak value. Moreover, the pulse current reduces the chemical potential of the reaction between SiCp and Mg matrix, thus promoting the reaction between SiCp and the alloy melt and stimulating the formation of Al4C3 along the grain boundaries. Furthermore, Al4C3 and MgO, as heterogeneous nucleation substrates, can induce heterogeneous nucleation and refine the solidification matrix structure. Finally, when increasing the peak value of the pulse current, the repulsive force between the particles increases while the agglomeration phenomenon is suppressed, which results in the dispersed distribution of SiC reinforcements.

Objectives. To identify the regularities of electrochemical processing of the heat-resistant GS32-VI alloy in a sulfuric acid electrolyte with a concentration of 100 g/dm3 under the action of a pulsed current in a pulsed mode.Methods. Using the electrochemical technological complex EHK-1012 (developed by IP Tetran) and a non-compensatory method of measuring potential, polarization and depolarization curves with a change in pulse duration and a pause between them were recorded. The current pulses had an amplitude ranging from 0 to 3.5 A (when recording the polarization and depolarization curves), pulse durations ranging from 200 to 1200 ms, and a pause (delay) between pulses ranging from 50 to 500 ms. There were no reverse current pulses.Results. The parameters of the current program that provide the maximum values of the alloy dissolution rate and current output were determined: with a current pulse amplitude of 2 A, a current pulse duration of 500 ms, and a pause duration between pulses of 250 ms, the maximum dissolution rate of the alloy is 0.048 g/h·cm2, while the current output for nickel is 61.6% with an anode area of 10 cm2. The basic technological scheme for processing the heat-resistant GS32-VI alloy, which includes anodic alloy dissolution in a pulsed mode, is proposed.Conclusions. Electrochemical dissolution of GS32-VI alloy under pulsed current action results in an optimal dissolution rate ratio of the alloy components, ensuring the production of a cathode precipitate with a total nickel and cobalt content of 97.5%.

In order to increase the gas blow formability of Ni foil, a two-dimensional pulse current auxiliary gas blow forming is proposed. In this paper, general free bulging tests, one-dimensional current auxiliary bulging tests, and two-dimensional current auxiliary bulging tests are carried out. The result indicates that the gas blow formability is improved by the two-dimensional pulse current. The ratio of height to diameter is up to 43.75% when the peak current density is 30 A/mm2. The ratio of height to diameter is 20.27% higher than that under the one-dimensional current, 44.63% higher than that under general free bulging forming. The mechanism of the two-dimensional pulse current on the deformation is studied. The result shows that the formability is improved more when the current direction is parallel to the radial strain direction. The pulse current can enhance the dislocation activity. Therefore, the formability of the Ni foil during gas blow forming can be increased.

With the wide application of nanocomposite protective coatings in various fields, there are higher requirements for their properties. At the same time, the traditional chemical deposition and electrodeposition processes have defects with different degrees. Nanocomposite coating was prepared by pulse current assisted chemical deposition process, which has the advantages of effectively improving the chemical deposition rate and ensuring the uniformity and compactness of the deposition layer surface morphology. In this paper, the effect of different duty ratios on Ni–P-(sol)Al2O3 nanocomposite deposition was studied. The surface morphology, composition, hardness, wear resistance and elastoplastic mechanical properties of the nanocomposite coating were tested through experiments. The experimental results showed that, when the duty ratio of pulse current was 20%, the prepared Ni–P-(sol)Al2O3 nano-composite deposition layer has the best performance, and its deposition rate reached 45.99 μm/h, hardness value was 629 HV, friction coefficient was 0.395, wear-width was 126.33 μm, Young modulus was 135.216 GPa, elastic recovery ratio he/hmax reached the maximum value of 0.3976, H3/E2 reached the maximum value of 0.0505 GPa. Compared with the coatings prepared by the traditional chemical deposition process, it is found that both coatings show good compactness and uniformity. However, the pulse-assisted chemical deposition method is significantly superior to the latter in hardness and wear resistance. The deposition layer prepared by pulse-assisted chemical deposition not only has a uniform and compact surface, but also has high hardness, good toughness and optimal wear resistance.

The charging and discharging performance of lithium-ion battery at low temperature will decline greatly, which seriously affects the adaptability of electric vehicles at low temperature. This paper proposes to use the inductance characteristic of the motor stator and the switching control characteristic of the motor controller to form pulse current in the battery, and realize the self-heating of the power battery at low temperature. Using this method the heating of the battery can be achieved without any additional hardware or cost. The experimental result shows the average temperature rise rate of the power battery reaches 2.88°C/min. And the influence of different parameters on the heating effect is analyzed through the experiments, including IGBT switching frequency, d-axis voltage, motor-rotor position, and battery internal resistance.

In this paper, to investigate the effect of loading method of pulse current on the tensile deformation behavior of AZ31B magnesium alloy sheet, the intermittent pulse current with short-time and high-frequency was introduced in uniaxial tensile tests and the influence of duty ratio and loading time of pulse current on the deformation behavior of AZ31B magnesium alloy sheet was discussed. The strain and temperature field distributions on the specimens were measured during the intermittent pulse electrically-assisted tension (IPEAT), and the microstructure and fracture morphology under different pulse current conditions were observed. Results shows appropriate pulse current parameters can effectively improve the elongation of AZ31B magnesium alloy sheet. The strain of the sample is closely related to temperature distribution. With the deformation of the sample, the temperature on the sample increases gradually and the temperature distribution is non-uniform along the tensile direction, resulting in an inhomogeneous strain distribution of the sample. In addition, grain growth and dynamic recrystallization were observed on the AZ31B magnesium alloy sheet in different degrees under intermittent pulse current. Fracture morphology analysis shows that the number of dimples and tearing edges increased on the fracture obtained under IPEAT. The microhardness analysis shows that when intermittent pulse current is applied in the tensile test, the hardness of the sheet may change. This research provides an effective idea for the forming process of magnesium alloy sheets, which can be used to form large size thin-walled sheet components, and can significantly improve the forming quality of the sheets.

In this study, Ni/W–TiN composites were fabricated by the pulse current electrodeposition (PCE) method. The effects of TiN concentration on the microstructure, microhardness, and wear properties of the resulting composites were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), microhardness tester, and friction wear testing. Among the four obtained composites, Ni/W–TiN composite prepared at 8 g/L showed the densest and finest surface structure. The TiN contents in obtained Ni/W–TiN composites at 8 and 16 g/L were estimated to 8.1 and 5.4 wt%, respectively. The average Ni/W grain diameter in Ni/W–TiN composite obtained at 8 g/L TiN was recorded as 84.7 nm. The protrusion and depression heights of the composite deposited at 8 g/L were 81.8 and 45.4 nm, respectively. This composite also processed an average microhardness of 897.6 HV, with only a few shallow and narrow scratches on its worn surface, demonstrating its prominent wear resistance when compared to the other three composites.

The problem of the real existence of the electroplastic effect during deformation of metallic materials of different nature is still relevant. At the same time, the influence of structure refinement is not considered enough. In this work, the deformation behavior of ultrafine-grained (UFG) titanium Grade 4 is compared with that of coarse-grained (CG) titanium under tension with pulse current of the low duty cycle. The deformation curves of both structure states are presented for different regimes of pulsed current and thermal heating from an external source. Structure studies by optical and scanning electron microscopy, as well as microhardness measurements have been carried out. It is shown that Grade 4 titanium under tension accompanied by pulsed current exhibits electroplastic effect (EPE) in the form of a flow stress reduction. EPE in UFG state is much stronger than in CG state. An increase in the density and duration of the current pulse leads to a multiple decrease in the flow stresses in CG and UFG titanium. The contribution in the flow stress reduction from heating by an external source was less than that from tension with pulse current at the same temperatures. The impact of pulsed current during tension does not influence microhardness and grain size.

Applications of lithium-ion batteries are widespread, ranging from electric vehicles to energy storage systems. In spite of nearly meeting the target in terms of energy density and cost, enhanced safety, lifetime, and second-life applications, there remain challenges. As a result of the difference between the electric characteristics of the cells, the degradation process is accelerated for battery packs containing many cells. The development of new generation battery solutions for transportation and grid storage with improved performance is the goal of this paper, which introduces the novel concept of Smart Battery that brings together batteries with advanced power electronics and artificial intelligence (AI). The key feature is a bypass device attached to each cell that can insert relaxation time to individual cell operation with minimal effect on the load. An advanced AI-based performance optimizer is trained to recognize early signs of accelerated degradation modes and to decide upon the optimal insertion of relaxation time. The resulting pulsed current operation has been proven to extend lifetime by up to 80% in laboratory aging conditions. The Smart Battery unique architecture uses a digital twin to accelerate the training of performance optimizers and predict failures. The Smart Battery technology is a new technology currently at the proof-of-concept stage.

This paper presents the effect of pulse frequency on the droplet transfer behavior and weld formation in local dry underwater welding (LDUW) based on micro-drainage device. Three different droplet transfer modes: projected transfer, globular transfer and spherical repelled transfer, were observed in the LDUW at the pulse current frequency of 25 Hz to 200 Hz. With the increase of pulse frequency from 100 Hz to 150 Hz, the direction of electromagnetic force changes, and the projected transfer becomes the globular transfer. With the increase of pulse frequency from 150 Hz to 200 Hz, the droplet transfer changes from the globular transfer to the spherical repelled transfer. The droplet transfer frequency decreases with the increase of pulse frequency. The weld formation with no obvious defects and relatedly deeper weld penetration were obtained in the mode of projected transfer, while in the mode of globular transfer, it is opposite. It is necessary to avoid the globular transfer, which would lead to the poor weld formation and minimum weld penetration.

The effects of pulse current on the tensile properties of high temperature titanium alloy Ti55 were investigated by pulse current assisted uniaxial tensile test under different electrical parameters. It was found that with the increase of peak current and pulse width, the tensile properties of Ti55 are significantly improved. At the same time, the pulsation effect of current on the mechanical properties of Ti55 was investigated. The results show that the tensile displacement of low pulsation group was higher, while the elongation of high pulsation group was higher. In order to explore the mechanism of pulsation effect of current, EBSD was adopted. The results indicated that high pulse current can significantly promote the dislocation movement and recrystallization. In addition, some macrozones was found in low pulsation group, which indicated that high pulsation current was more suitable for material forming than low pulsation current.

Neurons can exhibit abundant electrical activities in response to various externally applied stimuli, which can lay the groundwork for widening their use in neuron-based engineering applications. This paper presents the dynamical behaviors and analogy circuit-based confirmations in a bipolar pulse (BP) current-forced two-dimensional (2D) Wilson neuron model. Due to the existence of BP current, the proposed 2D neuron model has periodically switchable equilibrium states. The BP current-associated dynamical behaviors, including subthreshold oscillation (STO), periodic limit cycle, chaos, and antimonotonicity phenomenon, are numerically revealed by common dynamical analyses. Note that the electrical activity behaves a close dependence on the frequency of the externally applied BP current. Thereafter, an analog circuit is optimally synthesized to implement the 2D Wilson neuron model by utilizing the off-the-shelf discrete components, upon which the Multisim 12.0-based circuit simulations and hardware experiments are executed. It is revealed that the circuit-simulated and experimentally captured results well confirm the numerically simulated ones.

According to the characteristics of rail defects, a rail microcrack detection method based on magnetoacoustic coupling effect is proposed in this paper. Firstly, the basic principle of a rail microcrack detection method based on magnetoacoustic coupling effect is described, and then the model is analyzed theoretically. Through simulation calculation, the current density distribution and Lorentz force distribution generated by electromagnetic excitation, the motion characteristics of particles under Lorentz force and the sound field distribution characteristics of magnetoacoustic signals generated by Lorentz force are obtained. Finally, an experimental platform was set up and the steel ring model was preliminarily tested. The magnetic and acoustic signals of the two steel ring boundaries excited by an electromagnetic field were collected. These signals correspond to the position distribution of the steel ring. The state change of rail microstructure will cause a change in the conductivity characteristics of rail materials, and will affect the characteristics and distribution of sound pressure in the detection. Therefore, the detection method based on the magnetoacoustic coupling effect can detect the surface microcracks of high-speed rail. This method has great feasibility and development potential in the field of rail flaw detection.

Vibration attached to workpiece in EDM (Electrical Discharge Machining) makes material removal rate (MRR) and surface roughness (SR) to be improved significantly. However, research results in this field are not so much. In this work, authors studied effect of low frequency vibration attached to workpiece SKD61 to efficiency in EDM. The effect of process parameters including pulse current (I), pulse-on time (Ton), pulse-off time (Toff) and vibration frequency (F) on MRR and surface roughness was investigated. The optimized parameter in EDM process using TOPSIS based multi objectives problem were performed. The experimental results have shown that the process performance accuracy has been enhanced to 86.6% through the Ci in low frequecy vibration assisted EDM process. This surface morphology of the machined specimen could also be improved under optimal process parameters.

The process of electrodeposition of a tin-lead alloy from hydrofluoride electrolytes by pulsating currents has been investigated. The influence of the electric mode on the alloy composition and properties of the resulting precipitates was studied: current efficiency, microhardness, specific electrolytic resistance, and internal stresses of the precipitates.

Mathematical modeling of heat transfer in the film-substrate-thermostat system with a pulsed flow of high-density current through an electrically conductive film has been carried out. On the basis of the simulation, the analysis of the heating of a niobium nitride film with a high resistivity near the critical temperature of the transition to the superconducting state is made. The inhomogeneous heat conduction equation which is solved numerically, simulates heat transfer in the film-substrate-thermostat system for the third on the left and the first on the right initial boundary value problem. Using the symmetry of the problem, the parameter H is determined, which is equal to the ratio of the heat transfer of the film surface to its thermal conductivity; this parameter is necessary for effective heat removal. It is shown that effective heat removal from films can be provided by current-carrying and potential clamping contacts made, for example, of beryllium bronze. This makes possible to study the current-voltage characteristics of superconductors near the critical transition temperature to the superconducting state with high-density currents (104−105A/cm2) without significant heating of the samples.

The paper presents the results of studying the phase composition of iron-nickel alloys obtained by unsteady electrolysis. It was found that the use of a unipolar pulse current leads to a significant increase in the crystallization overvoltage at the crystallization front at the moment of the pulse action, which affects the component composition of the coatings. The phase composition of the alloys formed at the cathode differs from that shown in the iron-nickel equilibrium diagram.

Railway transportation is of safety, convenience, economy, and environmental friendliness. However, with energy issues becoming increasingly important in this century, it is important to assess the situation in the transportation sector. When the superconducting cable is used as a feeder of the railway electrification system, the voltage drop can be significantly reduced. Therefore, the superconducting feeder has many effects, for example, the reduction transmission losses, the improvement of the regeneration factor, and the reduction of substations. We designed superconducting feeder and introduced to the Izuhakone Railway Sunzu line in Japan. After the system was checked from the aspect of cooling and current properties, the train running test was conducted. From the result of switching notch tests, it was found that the current flows continuously via the superconducting cable according to the notch operation. Furthermore, to inspect the influence of superconducting material, a large pulse current test was performed using the transmission equipment of a railway. It can be confirmed that superconductor can be used as railway feeder because the materials can cope with the current change peculiar to railway required for practical use.

Ni-TiO2 nanocomposite coatings were fabricated on mild steel surface by pulsed direct current (PC) electrodeposition. This process was carried out in pulsed current at (1, 10, 50) Hz and a duty cycle (25%, 50%, 75%) respectively, at a minimum current density of 0 & high current density of 4 A/dm2. In this work the properties of nanocomposite films were investigated using scanning electron microscopy (SEM), Vickers microhardness measurements and Tafel polarization tests. The composition of the electrodeposits was analyzed by energy dispersive X-ray analysis (EDX). It was found that the coated surface contained at maximum 16.30 % Ti and 35.48 % O. XRD studies revealed [111] preferred orientation. Hardness increased from 560.4 Hv for Ni-TiO2 (F=10 Hz, DC=75 %) nanocomposite coating to 645.7 Hv for Ni-TiO2 (F=10 Hz, DC=25 %) nanocomposite coating. The corrosion resistance of Ni-TiO2 coatings was evaluated by potentiodynamic polarization studies in 3.5 % NaCl solutions. The Pulsed current offer composite coatings with uniform surface, high microhardness and enhanced corrosion resistance significantly for F=10Hz and DC=25 %.

Gas Tungsten Arc Welding (GTAW) has been extensively in use over a period in mechanical industry. Most of the problems associated with the structural development involving Aluminium is still a challenging and requires a methodological study to understand weldability of dissimilar Aluminium base materials. In this present study, mechanical and metallurgical properties of AA 2025, AA 5083 and AA 7075 weld joints made with GTAW have been presented. Mean pulse current of 80 A to 100 A was selected to join the similar and dissimilar base material combinations to make comparative studies. Difficult to weld base material combinations, AA 2027 with other selected base materials, and with non-heat treatable base materials were subjected to post weld heat treatment. Tensile and hardness tests were performed to evaluate the properties of as weld and post heated dissimilar weld joints.

Previous studies have shown that transcranial pulse current stimulation (tPCS) can increase cerebral neural plasticity and improve patients' locomotor function. However, the precise mechanisms underlying this effect remain unclear. In the present study, rat models of stroke established by occlusion of the right cerebral middle artery were subjected to tPCS, 20 minutes per day for 7 successive days. tPCS significantly reduced the Bederson score, increased the foot print area of the affected limbs, and reduced the standing time of affected limbs of rats with stroke compared with that before intervention. Immunofluorescence staining and western blot assay revealed that tPCS significantly increased the expression of microtubule-associated protein-2 and growth-associated protein-43 around the ischemic penumbra. This finding suggests that tPCS can improve the locomotor function of rats with stroke by regulating the expression of microtubule-associated protein-2 and growth-associated protein-43 around the ischemic penumbra. These findings may provide a new method for the clinical treatment of poststroke motor dysfunction and a theoretical basis for clinical application of tPCS. The study was approved by the Animal Use and Management Committee of Shanghai University of Traditional Chinese Medicine of China (approval No. PZSHUTCM190315003) on February 22, 2019.

Al–Li alloy has been widely used in the aerospace field owing to its high strength and low density. In this study, alternating current cold metal transfer (AC CMT) along with a high-frequency pulse current technique was used to weld a 2060 Al–Li alloy using an ER5356 wire. The effect of pulse frequency on the arc shape, microstructure, and mechanical properties of the welded joints was examined, and mechanical performance testing was conducted. The results revealed that the arc diameter, arc length, and arc volume showed a trend of increasing first and then decreasing with an increase in the pulse frequency and reached their peak values when the pulse frequency was 50 kHz. Coupling the welding process with a high-frequency pulse resulted in grain refinement, which was attributed to the stirring action of the arc force. Both the porosity levels and grain size decreased with increasing frequency. When the pulse frequency was 70 kHz, the porosity level was the lowest, and the grain size was refined to 24.1 μm. The tensile strength of the welded joints also increased with the pulse frequency, and a maximum tensile strength of 249 MPa was observed at 70 kHz.

The low efficiency of the electromagnetic forming is one of the obstacles for the advancement of this technology. Aiming at solving this issue, this paper presents a double tube-task electromagnetic forming technology method by employing a single driving coil to achieve tube compression and expansion at the same time. On the basis of electromagnetic forming principles and the law of energy conversion, this paper presents a new electromagnetic forming model for double tubes. The magnetic flux density distribution, electromagnetic force distribution and forming efficiency of the tube are analyzed and the effect of the equivalent pulse width of the driving coil current on the forming efficiency is investigated. Results show that in order to maintain the same plastic strain energy of the tube, the initial discharge energy required by the proposed double tube model is 25 kJ which is smaller than that required by a traditional single tube model (33.58kJ) and the efficiency can be improved by about 34.3%. The double tube model attains the maximum forming efficiency near the optimal current pulse width and can improve the low efficiency of traditional electromagnetic forming to a certain extent and provide more possibilities for this technological process.

Underwater pulse-current wet welding was proposed in part 1 of this two-part report. The novel technology obtained improved metal transfer and welding process stability. The main reason for droplet oversizing and long transfer cycles was found to be the deviated large droplet stage. In this part, the waveform optimization for both bubble behaviors and metal transfer were investigated. Efforts were made for shortening the duration of the deviated large droplet stage. Pulse current influences on bubble evolution was studied. It was found that two different separation modes can be adjusted by appropriately changing the current values when the bubbles are necking. Quickly reducing the welding cur-rent can sharply lower the impact force on the droplets due to intense gas flow changes inside. Under the optimized pulse current, the range of the metal transfer cycle became narrower, and droplet diameters were smaller than that of the original condition. Stable and improved metal transfer processes were achieved with a frequency of 7.52 Hz and an average droplet diameter of 2.4 mm, which was about 1.5 times the wire diameter. The optimized pulse waveform greatly improved weld formation with less spatter and a more uniform appearance.

This research investigates the measurement error on Wire EDM cutting products to find the pulse current's problem-solving. One of the machining parameters that affect the precision of Wire EDM is the magnitude of the current. The experimental study carried out by using the pulse current started from 4-Ampere up to 8-Ampere as the research parameters. A chamfer dimension on 6061 Aluminum alloy was investigated with the gd&t method with ISO 5459 and ISO 1101 standard. Statistic method applied and processed on Minitab with Shapiro-Wilk parameter for normal distribution. These experimental studies have a normal distribution that finds the phenomena of 8-Ampere of pulse current generate a large measurement error. Furthermore, in these experimental studies, the usage of a Profile Projector generates a massive measurement error, up to 64.5% compared with CMM. A strong commitment to calibrate the Profile Projector up to date to maintain the machining quality.

The electrochemical performances of deposited MnO2 on lead alloy anode by pulse current (PC) and direct current (DC) electrodeposition in manganese sulfate solution were investigated by performing ...

To determine the relationship between the pulse current and the physicochemical properties of multi-time scales, a method of multi-time scale simulation is introduced to investigate multi-time scale evolution of temperature and void fraction in PECM process. A multi-time scale iterations method is introduced to reduce computation time of multi-time scale simulation. Simulation results indicate that the method is efficient and pulse current can make the PECM process more stable. Experimental results show that the multi-time scale simulation results can well match the actual machining results, especially in the middle section of the workpiece.

A high voltage pulse generator was development and implemented. It generates a sequence spike pulses with a varying pulse height from 0 to 5 kV; and changes the pulse width in ms range. This generator tested and used to study the pulse glow discharge in argon by using the capillary tube under pressure 0.3 to 0.5 torr. This study was to establish the nature of discharge relaxation (plasma relaxation) when a high voltage pulse causes a breakdown in the gas (coverts to conducting case). It is of great importance to answer the following question. The current can decay when the voltage pulse is switched off was obtained. The electronic switching is a successful tool which can be used for generating high voltage pulses with flexibility adjustable peak height voltage pulse, pulse duration and pulse width is presented Interesting results concerning because plasma is a function of time, linearity of time decay vs. plasma. This linearity is to seem independent on gas pressure or pulse width. The slope the current decay line is very much dependent upon the initial high voltage pulse. The condition for transition from pulse to continue like DC glow discharge condition is satisfied.

Periodically changed current is called pulse current. It has been found that using the pulse current to charge/discharge lithium-ion batteries can improve the safety and cycle stability of the battery. In this short review, the mechanisms of pulse current improving the performance of lithium-ion batteries are summarized from four aspects: activation, warming up, fast charging and inhibition of lithium dendrites. Related content may help us use the pulse current to improve the performance of lithium-ion batteries and further optimize pulse current technology.

The effect of pulse current on the serrated flow of 5086 Al alloy was investigated through uniaxial tensile test at room temperature. The serrated yielding phenomenon was observed without pulse cur...

In order to study the effect of pulse current treatment on the mechanical properties, microstructure and cutting performance of YG8 cemented carbide, experiments were carried out by using self-made pulse current treatment device to treat cemented carbide samples with different current densities (J = 5, 10 and 15 A·mm−2). After the treatment of pulse current, when the current density increased from 5 to 15 A·mm−2, the hardness of the sample was improved to HV 1605, HV 1629 and HV 1653 from HV 1574; the transverse rupture strengths of the sample were 2136, 2289 and 2364 MPa, which were all higher than that of the untreated sample (2062 MPa), increasing by 3.6%, 11.0% and 14.6%, respectively; the corresponding cutting performance was increased by 10.1%, 13.9% and 19.4%, compared to that of the untreated tool. The tool’s life was also improved. After the treatment of pulse current, pulse current provided the driving force for dislocation motion, making it more likely for the dislocation to multiply and slip, the dislocation density was increased, and the mechanical properties were significantly improved.

The typical metal transfer mode in conventional underwater wet flux cored arc welding (FCAW) delivers large droplet repulsive transfer with low frequency. The process stability and the weld quality are seriously deteriorated with significant spatter and frequent arc extinctions. It is thought the repulsive forces applied on droplets can be reduced by rapidly decreasing the welding current, making the droplets sag and oscillate. A novel underwater pulsecurrent FCAW was proposed to periodically regulate the forces applied on droplets. The experimental system was developed with specially designed pulse current and reliable arc length control. Visual and electrical signals were collected simultaneously to study the process features. It was found that the maximum droplet diameter decreased to less than 5 mm; the temporary arc-extinguishing frequency decreased significantly; there was almost no short-circuit transfer and surface-tension transfer; and the stability of the welding process was significantly improved.

A high-density pulse current was introduced into the V-shaped bending process to reduce the bending springback of nanocrystalline Ni foil. The effect of different pulse current densities on the springback angle was studied. The bending angles of the samples were annotated by SEM images, and the action mechanism of pulse current on the bending process of nanocrystalline Ni foil was analyzed by TEM images. The experimental results show that the bending springback angle of nanocrystalline Ni foil gradually decreases with the increase in the pulse current density. The results of TEM image analysis show that the introduction of pulse current during the bending deformation of nanocrystalline Ni foil can promote dislocation movement and grain rotation and thus promoting the transformation from elastic strain to plastic strain and improving the plasticity of nanocrystalline Ni foil.

The pulse current oxidation methods were used to degrade the malachite green (MG) using lead dioxide as anodes. The influences of operating parameters, including pulse frequency, pulse curr...

In this study, a novel structure of layered Ti-B4C/AA6061 composite with different B4C particles contents was designed and fabricated by pulse current sintering, and its microstructure and mechanic...

The impacts of pulse current electroplating variables such as frequency, duty cycle, and concentration of titanium carbide nanoparticles on the morphology of Ni–W–TiC nanocomposite coating applied ...

The main dielectric medium in converter transformers is the oil-pressboard. The valve windings of converter transformers are subjected to AC-DC combined voltage. Creepage discharge is a common defect of oil-pressboard insulation. The degree of the oil-immersed pressboard (OIP) damage is directly affected by different creepage discharge paths. In this study, a needle-plate model was developed to explore different creepage discharge paths in oil-pressboard insulation under AC-DC combined voltage. A high-speed camera was used to record the developmental process of white marks on the OIP. We explored reasons behind the different creepage discharge paths under different voltage types. Results revealed that the creepage discharge path and the degree of OIP damage were influenced by the DC component. Although the damaged OIP in converter transformers may cause catastrophic flashover inside the transformers, it is difficult to replace it. This implies that transformer insulation designers should pay attention to the influence of the DC component on OIP damage. In this study, we used pulse current method to detect discharge patterns. Discharge parameters were then extracted from discharge patterns. We observed that developmental process of white marks corresponded to developmental process of discharge parameters. This suggests that creepage discharges can be diagnosed based on discharge parameters. Based on these conclusions, important information was provided for the on-line monitoring design of transformer insulation status.

Improving the forming efficiency at a reasonable cost has been the main challenge in the electromagnetic forming technology. Towards this aim, this paper proposes a simultaneous cost-effective double-sheet electromagnetic forming method using single driving coil. In order to highlight the features of the proposed technique, comparison of the performance of five electromagnetic forming models is presented. These models include a no-sheet model, single-sheet stationary model, single-sheet moving model, double-sheet stationary model and double-sheet moving model. For each model, electromagnetic force distribution and forming efficiency of the workpiece are analyzed. Furthermore, the influence of the pulse current width of the driving coil on the electromagnetic forming efficiency of the plate is investigated for all models. Results show that for the same system discharge parameters, electromagnetic forming efficiency of double-sheet is 21.14% whereas the single-sheet electromagnetic forming model only achieves 14.68% efficiency. Thus, the double-sheet electromagnetic forming technology can improve the low forming efficiency of a single-sheet electromagnetic forming method and at the same time, the method can form two workpieces simultaneously which makes it more cost effective than the single-sheet method.

In this paper Jaya algorithm is successfully applied to solve optimization problem. Material Removal Rate (MRR), Tool wear Rate (TWR), Radial Overcut (G) are taken as response function and Maximize, minimize and minimize respectively. While four EDM parameter considered as input parameter i.e. pulse current (Ip), pulse on time (Ton), duty cycle (Tau) and gap voltage (V). After experiment mathematical model were developed by Minitab 18. Optimization done by Jaya algorithm

This paper deals with an advanced electromagnetic radiation approach for analyzing the time-domain performance of grounding systems under pulse excitation currents. The model of the grounding systems presented within this paper is based on the homogeneous Pocklington integro-differential equation for the calculation of the current distribution on the grounding system and Lorentz gauge condition which is used for the grounding system transient voltage calculation. For the solution of the Pocklington integro-differential equation, the indirect boundary element method and marching on-in time method are used. Fur- thermore, the solution technique for the calculation of the grounding system transient voltage is presented. The numerical model for the calculation of the grounding system transients was verified by comparing it with onsite measurement results.

Представлены результаты исследования физических условий возникновения пондеромоторных эффектов в условиях электропластической деформации. Показано, что при электропластической деформации происходит реализация оптимальных значений пондеромоторых факторов при таких частотах, когда магнитное поле в материал проникает несущественно, а скорость диффузии зависит от проводимости и частоты пропускаемого через материал тока. Выявлено, что скин-эффект, возникающий от высокочастотного тока, вызывает вихревые токи, препятствующие равномерному распределению плотности по поперечному сечению проводника, а возникающий при этом скин-слой имеет меньшую плотность тока на оси, по сравнению с поверхностью. Установлено, что электромагнитные поля смещаются к поверхности образца с ростом частоты импульсов тока, а с увеличением диаметра образца превуалирует уменьшение плотности тока и рост напряженности магнитного поля. Authors present the results of investigation of physical conditions of occurrence of ponderomotor effects in conditions of electroplastic deformation. It has been shown that with electroplastic deformation, optimal values of ponderomotor factors are realized at such frequencies when the magnetic field penetrates the material insignificantly, and the diffusion rate depends on the conductivity and frequency of current passed through the material. It was revealed that the skin effect arising from the high-frequency current causes eddy currents that prevent uniform distribution of density over the cross section of the conductor, and the resulting skin layer has a lower current density on the axis compared to the surface. It was found that electromagnetic fields are shifted to the surface of the sample with increasing frequency of current pulses, and with increasing diameter of the sample, a decrease in current density and an increase in magnetic field strength are surpassed.

Тема выпускной квалификационной работы: «Моделирование влияния импульсного электрического тока на внутренний дефект в проводнике». Данная работа посвящена определению Ð´ÐµÐ¹ÑÑ‚Ð²ÑƒÑŽÑ‰Ð¸Ñ Ñ„Ð°ÐºÑ‚Ð¾Ñ€Ð¾Ð², Ð²Ð»Ð¸ÑÑŽÑ‰Ð¸Ñ Ð½Ð° процесс залечивания дефектов проводников при протекании импульсного тока. Задачи, решаемые в Ñ Ð¾Ð´Ðµ исследования:1. Изучение особенностей протекания импульсного тока в Ð¿Ñ€Ð¾Ð²Ð¾Ð´Ð½Ð¸ÐºÐ°Ñ .2. Изучение разрушения и залечивания проводников при протекании импульсного тока.3. Моделирование процесса залечивания внутреннего дефекта проводника при протекании импульсного тока в 3D постановке в среде COMSOL. 4. С помощью изменения Ð´ÐµÐ¹ÑÑ‚Ð²ÑƒÑŽÑ‰Ð¸Ñ Ñ„Ð°ÐºÑ‚Ð¾Ñ€Ð¾Ð² добиться ÑÑ Ð»Ð¾Ð¿Ñ‹Ð²Ð°Ð½Ð¸Ñ внутреннего дефекта.5. Оценка влияния Ñ€Ð°Ð·Ð»Ð¸Ñ‡Ð½Ñ‹Ñ Ð´ÐµÐ¹ÑÑ‚Ð²ÑƒÑŽÑ‰Ð¸Ñ Ñ„Ð°ÐºÑ‚Ð¾Ñ€Ð¾Ð² на процесс залечивания дефекта. В результате проделанной работы было определено, что импульсный ток высокой плотности позволяет не только эффективно устранять уже существующие дефекты в материале, но также и восстанавливать Ð¼ÐµÑ Ð°Ð½Ð¸Ñ‡ÐµÑÐºÐ¸Ðµ свойства материалов.Â, The subject of the graduate qualification work is « Modeling the effect of pulsed electric current on the internal defect in a conductor».This work is devoted to determining the operating factors affecting the process of healing defects in conductors during the flow of pulsed current. Tasks that are solved in the course of the study:1. Study of the peculiarities of pulse current flow in conductors.2. Study of fracture and healing of conductors under pulse current flow. 3. Modeling of the healing process of an internal conductor defect during pulse current flow in a 3D setting in the COMSOL environment. 4. By changing the acting factors to achieve the collapse of the internal defect. 5. Assessment of the influence of various acting factors on the defect healing process. As a result of this work, it was determined that high-density pulsed current not only makes it possible to effectively eliminate existing defects in the material, but also to restore the mechanical properties of materials.