Wire Explosion Research Articles

Ag–Cu/Pmma Nanocomposites Produced By Modification of PMMA with Bimetallic EEW-Nanoparticles

Using the method of electrical explosion of copper and silver wires in an argon atmosphere, Cu–94Ag, Cu–65Ag, and Cu–22Ag bimetallic nanoparticles are manufactured. The resulting nanoparticles are characterized by the methods of transmission electron microscopy and X-ray diffraction analysis. It is shown that irrespective of the component ratio all particles have spherical shapes, with copper and silver uniformly distributed in their volume. The phases identified in the samples correspond to silver- and copper-based solid solutions. The conditions for an ultrasonic dispersion of nanoparticle suspensions are selected. The sedimentation analysis data indicate that the minimal time of ultrasonic treatment at a power of 23 kW is 5min for Cu–65Ag and Cu–22Ag nanoparticles and 2 min for Cu–94Ag nanopowder. The fabricated nanoparticles are used as antibacterial modifiers of PMMA. The Ag–Cu/PMMA composites demonstrate a high antibacterial activity against Escherichia coli.

Scavenging of Free Radicals Generated in Biological Tissues Exposed to Ionizing Radiation Using Silver Nanoparticles

Humans are exposed to nuclear radiations every day, and these radiations are both natural and artificial. When the body tissues are exposed to nuclear radiation, free radicals are formed, which are responsible for cancer development. In this research, silver nanoparticles were synthesized by electrical explosion wire method. Nanoparticles were added to deionized water that contained free radicals before and after exposure to gamma rays. The obtained results indicate that the silver nanoparticles have antioxidant potential through possessing free radical scavenging activity, as they can donate electron to free radicals and become neutralize. Then, these nanoparticles were injected to mice before and after their irradiation with gamma ray. The liver and kidney of the mice were shown to be unaffected by gamma irradiation.

Explosive electrical wire failures behave differently depending on the voltage applied

High-speed imaging of electrical wire failure reveals regions of fluid instability, bubble growth and rapid change from fluid breakup to phase explosion.

High-speed imaging of transition from fluid breakup to phase explosion in electric explosion of tungsten wires in air

High-speed visible imaging of sub-microsecond electric explosion of wires at the low specific energy deposition threshold reveals three distinct modes of wire failure as capacitor charge voltage and energy deposition are increased. For 100 μm diameter gold-plated tungsten wires of 2 cm length, deposited energies of 1.9 eV/atom produce a liquid column that undergoes hydrodynamic breakup into droplets with radii of the order of wire diameter on timescales of 200 μs. Instability growth, column breakup, and droplet coalescence follow classical Rayleigh–Plateau predictions for instability of the viscous fluid column. Above a deposited energy of 3.2 eV/atom, wires are seen to abruptly transition to an expanding mixture of micrometer scale liquid-droplets and vapor within one frame (less than 3.33 μs), which has been termed “phase explosion” in the literature. Between these two limits, at a deposited energy of 2.5 eV/atom, the wire radius remains unchanged for the first 10 μs before the onset of a rapid expansion and disintegration that resembles homogenous nucleation of mechanically unstable bubbles. Thermodynamic calculations are presented, which separate cases by temperature obtained during heating: below the boiling point, near the boiling point, and exceeding the boiling point.

Dual-Wavelength Interferometric Measurement of Electrically Exploded Aluminum and Copper Wires in Low-Pressure Air for Electron and Ion Density Calculation

Electron and atomic densities of Cu and Al plasmas in low-pressure air are studied using the recently reported dual-wavelength (1064 and 532 nm) interferometric diagnostic. The electrical explosion of a 99.999% pure, straight wire forms cylindrical plasma volumes within a low-pressure air chamber, and the probing lasers' interferometry patterns are simultaneously recorded at prescribed times after wire explosion. The measurements are performed repeatedly from 50 to 1200 ns in 50-ns increments allowing the calculation of electron and ion densities and the observation of the plasma's expansion and dissipation. The densities are calculated from fringe line analysis using a signal-processing-based algorithm that automatically extracts the fringe ratio. Finally, the maximum average volumetric electron and ion densities are calculated. The results of atomic density agree with past reports but are two orders greater than electron density, which suggests that full ionization is unattained.

Application of Silver Nanofluids on Kinetics of Sulfur Hexafluoride Gas Hydrate Formation.

Gas hydrates are nonstoichiometric nano-structured crystalline compounds which are stabilized by gas molecules incorporated in the cages made of hydrogen bonding of water molecules at suitable thermodynamic conditions. The gas hydrate as a technology has been successful for several potential applications in various engineering fields, such as, gas separation, carbon dioxide sequestration, gas storage and transportation, desalination of salt water and wastewater treatment. Recently, metal-based nanofluids are considered as interesting kinetic promoter candidates for accelerating formation of gas hydrates. Although organic-based kinetic promoters are widely studied for the rapid formation of gas hydrates, research of a new material system is still a challenge. In this study, Silver (Ag) nanofluids as kinetic promoter of sulfur hexafluoride (SF6) hydrate were prepared by electrical explosion of pure metal wire in deionized water. The kinetics of SF6 gas hydrates were evaluated with different concentration of Ag nanofluids at condition of 276 K and 0.7 MPa, respectively. The Ag nanofluids, as kinetic nano-prompter, showed excellent effect on the formation of SF6 hydrates.

Detection of Cells Containing Internalized Multidomain Magnetic Iron (II, III) Oxide Nanoparticles Using the Magnetic Resonance Imaging Method

This study evaluated the feasibility of using uncoated iron (II, III) oxide nanoparticles (IONP) obtained by electric explosion of wire in air for labelling living mesenchymal stromal cells and their subsequent visualization by magnetic resonance imaging (MRI) using the 1T and 1.5T clinical MRI scanners. The uptake of uncoated IONP by MSC was demonstrated for the wide range of IONP concentration in the cell culture medium. The cells did not change their proliferative activity, viability, and the set of surface markers. Iron oxide nanoparticles obtained by an electric explosion of wire in an atmosphere of air had a shape close to spherical. According to dynamic lateral light scattering, laser diffraction, and transmission electron microscopy, the particle size varied from 14 to 136 nm. Particles up to 136 nm accounted for 75%, while particles less than 36 nm accounted for 10%. A wide range of particle sizes made it possible to select MRI parameters suitable for labelled cells detection in animal tissues in both the T2 and the T1 relaxation mode.

Effect of the Length of the Interelectrode Gap during an Underwater Spark Discharge and the Length of a Conductor during Its Underwater Electrical Explosion on the Amplitude of the Generated Pressure Wave

Experimental results on the effect of the length of the discharge gap during an underwater spark discharge and the length of the metal conductor at its underwater electrical explosion are presented. In both cases, the dependence of the pressure wave amplitude on the length of the interelectrode gap or the conductor length has an optimum at which the pressure wave with a maximum amplitude is generated. In this respect, it is necessary to realize the modes with an optimal value of the length of the interelectrode gap, which ensures the efficient electrodischarge effect on the object treated. During the underwater spark discharge, it also allows realizing the mode close to critical, which positively affects the resource and lifetime of the electrodischarge equipment. It is shown that the change in the length of the metal conductor at its underwater explosion with the invariable parameters of the discharge circuit changes the mode of the underwater electrical wire explosion.

A New High-Efficiency Power Management Circuit for a Novel Two-Phase Compensated Pulse Alternator

A new, high-efficiency power management circuit for a novel small-sized, two-phase compensated pulse alternator (compulsator) is designed to provide high pulsed powers, making itself a promising compact power supply system for a number of applications, like producing nanosized powders by explosion of wires. The design and manufacture of this novel small-sized compulsator was successful with favorable efficiency validated. Along with this, compulsator is a newly designed high-efficiency power converter circuitry designed by this study for converting the alternating power generated by the compulsator to unipolar pulse power. The designed converter consists of two parallel single-phase rectifiers on the two-phase power generated by the designed compulsator. The rectification is enabled by using thyristors as power switches for the converter. The switching of thyristors is made possible by all-analog controller circuits, which decide the firing angle based on sensed pulsed power in two phases in real time. Experiments are conducted, with the result showing that the designed compulsator and power management circuit can generate a peak current up to the level of 2.178 kA. and a current density of 96.133 kA/m2, which was never seen by prior works.

Dimensional effects of electrically exploding aluminum wires in argon gas: Experimental investigation

The strong dependence of electrical explosion of wires (EEW) on wire dimensions is demonstrated experimentally from three perspectives: electrical characteristics, spatial structures, and nanopowder properties. Electrical characteristics of EEW were explored by measuring current and voltage waveforms of exploding 20–100 μm-diameter and 2–10 cm-long wires in argon gas. The discharge mode, energy deposition, and breakdown characteristics of EEW were analyzed based on the calculation of several electrical parameters. Laser-based diagnostics and multi-frame photographs were used to obtain the EEW spatial structures and their evolutionary characteristics. The radial distribution of exploding wires in the early and diffusion stages was obtained according to the analysis of shadowgraphs and interference images. The optical observations suggested that nonuniformity of EEW spatial structures becomes appreciable with the increase of wire dimensions. Inhomogeneities in exploding wires (e.g., residual cores, gaps, local hot spots, and stratification phenomena) and the causes of their formation were also discussed. The morphology and particle size distribution of nanopowders produced by EEW were also observed via transmission electron microscopy as well. The statistical results show that increasing wire dimensions (diameter and length) increase the average diameter and broaden the size distribution of nanopowders.

Electrical explosion of nickel wire as an efficient method for large-scale preparation of nickel oxide nanopowders: evaluation of operational key factors on the average crystallite size and average size distribution using response surface methodology (RSM)

The electrical explosion of wire (EEW) method provides a sufficiently route for large-scale preparation of nickel oxide nanopowders (NiO-NPs) with a small degree of contamination. In this study, Central composite design of the response surface methodology (RSM) was firstly employed to evaluate the average crystallite size (ACS) and average size distribution (ASD) of NiO-NPs. Twenty types of NiO-NPs were prepared by adjusting three operating parameters (wire diameter, the distance between two electrodes and the voltage) at five levels by the method of multiple variable analysis. The check experiments revealed that all the three operating parameters have significant effect on the ACS and ASD of NiO-NPs. For each response, a suitable second-order regression equation was obtained by applying analysis of variance. In addition, the results revealed acceptable agreement among experimental data and predicted results. Moreover, the optimum region for production of NiO-NPs with size below 100 nm by EEW method was obtained. Characterization of NiO p-type semiconductor in terms of size distribution, morphology, chemical composition and phase structure was carried out by TEM, SEM/EDX, XRD and BET analyses. The results nominated the EEW technique as a unique method for large-scale and economic preparation of NiO-NPs with defined structural features.

The synthesis of Fe-Ag and Fe-Cu bimetallic nanoparticles by electrical explosion of wires

In the present study, we obtained antibacterial Fe-Cu and Fe-Ag bimetallic nanoparticles by electrical explosion of two twisted wires. This method allows obtaining nanoparticles of a given composition and morphology. As-synthesized nanoparticles were characterized by electron microscopy, X-ray diffraction, micro electrophoresis techniques and magnet technique. In result we observed the formation of nanoparticles with Janus-like structure with distinct separation of components inside the particle. These nanoparticles have a strong antibacterial activity against two bacteria strains. The high antimicrobial activity of the nanoparticles is due to the prolonged ion release in media. Taking into account the possibility of easy magnetic separation of the novel bimetallic demonstrate the potential for their use as promising new generation antibacterial agents for advanced antimicrobial water treatment technologies.

Peroxymonosulfate activation by carbon-encapsulated metal nanoparticles: Switching the primary reaction route and increasing chemical stability

This study explores the technical merits of carbon encapsulation via an electrical wire explosion method to enhance the peroxymonosulfate activation performance of metals. Reflecting the nature of core-shell structures, the outer carbon layers hampered the reductive conversion of peroxymonosulfate to sulfate radicals by the inner metal cores, whereas the metal cores increased the overall electrical conductivity as a pivotal factor in non-radical activation. Hence, the impact of carbon wrapping hinged on the peroxymonosulfate reduction capability of the metals, i.e., kinetic retardation in organic degradation with reactive Cu, Fe, and Ni-Fe, but acceleration with unreactive Ni. Further, composite fabrication switched the major degradative pathway from radical-induced oxidation to mediated electron transfer, as determined from the effects of methanol and chloride, formaldehyde and bromate formation yields, reactivity toward multiple organics, and electron paramagnetic resonance spectral features. The protective carbon shells enabled pH-insensitive peroxymonosulfate activation, prevented metal ion leaching, and alleviated catalyst deactivation.

Study of burning rate characteristics of propellants containing Al–Mg alloy nanopowder

Nanopowder of Al–Mg alloy was synthesized using the method of electrical explosion of thin wires of hypo-eutectic Al–Mg alloy. Thin wires of hypo-eutectic Al–Mg alloy were cut by electrical discharge machining and exploded electrically. The nanopowder obtained is examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for studying the morphology of the particles. TEM and SEM images substantiate the spherical structure of the nanoparticles and the diameter of particles ranges from 20 nm to 95 nm. Solid propellants were prepared by adding the alloy nanopowder as an energetic additive element with bimodal ammonium perchlorate (AP) and Hydroxyl Terminated Polybutadiene (HTPB) propellant formulations. Burning rates of the propellant with nano Al–Mg alloy powder are compared with micro aluminised propellants and propellants with micro Al–Mg powder with the same composition. Mean burn rate of 22.03 mm s−1 was obtained at a pressure level of 9 MPa with nano Al–Mg powder and 20.4 mm s−1 with micro Al–Mg powder compared to mean burning rate of 10.03 mm s−1 at 8 MPa pressure for aluminised propellants. The improved mean burn rate of propellants containing Al–Mg alloy nanoparticles could be accounted for the reduction in the size of the alloy particle and selective melting of eutectic phases along with magnesium. In the process, it gives heat feedback to the high-temperature reaction zone, which results in augmenting further reaction of metal particles.

Experiments on the characteristics of underwater electrical wire explosions for reservoir stimulation

Underwater shock waves generated by pulsed electrical discharges are an effective, economical, and environmentally friendly means of stimulating reservoirs, and this technology has received much attention and intensive research in the past few years. This paper reviews the main results of recent work on underwater electrical wire explosion (UEWE) for reservoir stimulation. A platform is developed for microsecond single-wire explosions in water, and diagnostics based on a voltage probe, current coil, pressure probe, photodiode, and spectrometer are used to characterize the UEWE process and accompanying shock waves. First, the UEWE characteristics under different discharge types are studied and general principles are clarified. Second, the shock-wave generation mechanism is investigated experimentally by interrupting the electrical energy injection into the wire at different stages of the wire-explosion process. It is found that the vaporization process is vital for the formation of shock waves, whereas the energy deposited after voltage collapse has only a limited effect. Furthermore, the relationships between the electrical-circuit and shock-wave parameters are investigated, and an empirical approach is developed for estimating the shock-wave parameters. Third, how the wire material and water state affect the wire-explosion process is studied. To adjust the shock-wave parameters, a promising method concerning energetic material load is proposed and tested. Finally, the fracturing effect of the pulsed-discharge shock waves is discussed, as briefly are some of the difficulties associated with UEWE-based reservoir stimulation.

Shockwave generation by electrical explosion of cylindrical wire arrays in hydrogen peroxide/water solutions

We report the results of experiments investigating the implosion of a shock generated by the electrical explosion of a cylindrical aluminum wire array immersed in a >80% hydrogen peroxide/water solution. This solution was chosen as an additional energy source to the supplied electrical energy to generate the imploding flow with higher velocity. The experiments were conducted using a generator with the stored energy of ∼4.8 kJ, delivering to the array a ≤280 kA current rising during ∼1 μs. The backlighted images of the imploding shocks were recorded using a streak camera. Using different diameter wires, the explosion of arrays, characterized by critically damped and under-damped discharges, was studied. The experiments revealed that an array explosion in a 92% H2O2/H2O solution results in the second strong shock generated after the peak of the deposited electrical power, a solid indication of H2O2 detonation. This second shock converges ∼40% faster than the first strong shock generated by the wire explosion. One-dimensional hydrodynamic simulations of the shock convergence in H2O2/H2O solutions support this proposition.

An Image Converter Camera for Studying Processes in the Nano- and Microsecond Ranges

A chronographic image converter camera has been designed on the basis of a PIF-01 image converter tube to obtain spatial and temporal information in a study of light processes in the nano- and microsecond ranges. The duration of scans on a 25-mm-diameter screen of the camera can be varied from 0.5 to 10 µs with a limiting time resolution of 2 ns or better. Possible applications of the developed camera for spectral and time measurements of processes in real experiments on the study of electric explosion of tungsten wires are described.

Spatial–temporal evolution of plasma radiation in electrical wire explosion: a morphological observation

This paper deals with an experimental study regarding the spatial–temporal evolution of single wire explosions in air and water at atmospheric pressure. Experiments were carried out with a microsecond timescale pulsed current source under 500 J stored energy. The morphology of the exploding wire with different discharge type, wire material, insulating coat, and ambient medium was intensively observed via self-emission images. The results revealed that the plasma radiation of wire explosion in air mainly contained two stages: initial intense radiation from optically thick plasma, and later decaying radiation from expanded arc-like plasma. A hollow structure was observed in a Cu exploding wire in air, and the plasma channel tended to develop inside it. As for W case, there would always be a core-corona structure, resulting in lower expansion rate and shock wave strength. Moreover, the plasma radiation of the underwater wire explosion was mainly determined by two factors: expansion rate and chemical reaction. The expansion rate of the radiant region in water was only 10–1 mm μs–1 level (1 mm μs–1 level for air), leading to the lagging radiation. No noticeable difference in morphology was found between Cu and W wire explosions in water. Particularly, the Al wire explosion generated a bright light emission due to chemical reactions. Finally, radiative characteristics in an exploding wire were preliminarily concluded and existing problems proposed.

Optimization of carbon coating thickness to prevent crack generation in Sn nanoparticles during charge/discharge process and their electrochemical properties

Abstract One of the drawback of Tin (Sn) as anode material for Li-ion batteries (LIBs) is severe capacity fading due to pulverization of Sn particles during cycling. Many researchers have tried to solve this problem through various carbon coating on the surface of Sn particles. In this work, Sn/Carbon nanoparticles having various carbon coating thicknesses (0.0–7.0 nm) on the surface of Sn nanoparticles was fabricated by using pulsed wire explosion within various alcohol-based liquid media. The optimum carbon coating thickness needed to prevent crack of Sn nanoparticles was investigated. It was also investigated on when the cracks occurred during cycling using electrochemical analysis and acoustic emission signal analysis. It was found that around 95% of the crack is detected in the first cycling and the appropriate thickness of the carbon layer for the crack suppression is more than 5 nm.

Influence of wire parameters on the formability of DP600 steel sheets during wire explosion impact forming

The acoustic pulses caused by the underwater wire explosion can be used to apply work on the surrounding medium. This work designed a set of adjustable wire explosion impact forming tooling to investigate the influence of wire parameters on the formability of DP600 steel sheets. The results obtained based on the current experimental conditions showed that a longer wire length mainly played a positive role in improving the energy utilization rate; a larger lifting height weakened the disadvantage of uneven distribution of pressure caused by the explosion of metal wire, and decreased the difference between the radial pressure and the circumferential pressure of the fractured elements, causing the limit strain pair to be closer to the equi-biaxial tensile strain path and increasing the limit dome heights of the tested specimens. Under the conditions of optimal wire length of 45 mm and lifting height of 37 mm, the limit dome heights and the major strains of the tested specimens were increased by 10% and 20%, respectively, as compared with quasi-static specimens; and the energy utilization rate was improved by 30–50% as compared with other combined wire parameters. The numerical simulation reproduced the dynamic deformation process of tested specimens and showed that the maximum effective strain rate was 1740/s, which was 106 times of that during the quasi-static hydraulic bulging process. The microstructural characteristics showed that under the action of high-speed impact load, the grain size of the tested specimen was reduced by 80%, as compared with that under quasi-static condition.