Search

BACKGROUND: Ammonia removal from wastewater by electrooxidation (EO) is an interesting approach because of its efficiency and easy maintenance and operation. In this process, ammonia is oxidized to nitrate or nitrogen gas. Ammonia conversion to the latter is desirable to remove nitrogen from the liquid; however, the influence of several operating parameters on nitrate generation has not been systematically evaluated. Therefore, this work aimed to investigate the effect of current density (200–800 A m−2), chloride concentration (0–10 000 mg L) and initial pH (5–9) on the electrooxidation of an ammonia‐containing solution and the associated generation of nitrate. For this purpose, a laboratory‐scale electrochemical reactor containing two Ti/RuO2 electrodes was used. RESULTS: The results indicated high ammonia removal efficiency – 98% within 150 min at 800 A m−2 and 97% within 240 min at 500 A m−2 – generating around 70 and 102 mg NO3−‐N L−1 under these conditions, respectively. Increasing the chloride concentration from 5000 to 7500 mg L−1 reduces the electrolysis time needed to remove all ammonia from 180 to 150 min. However, with increasing initial chloride concentration, the amount of nitrate generated rose from 69.5 to 135.9 mg N L−1. On the other hand, in the test without chloride, nitrate generation was considerably lower (0–0.61 mg L−1). CONCLUSION: The higher the current density applied, the greater the ammonia removal by EO. Although current density influenced the ammonia oxidation rates, it did not directly affect nitrate formation. The lower the concentration of ammonia in the solution, the more significant was the fraction of nitrate generated. Most of the inlet ammonia was oxidized to nitrogen gas, nitrite was rapidly oxidized to nitrate and higher chloride concentrations enhanced ammonia oxidation. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell (SOFC) has attracted wide attention because its efficiency is not limited by the efficiency of Carnot cycle. The structure of flow channel in SOFC has great effects on the internal mass distribution, which influences current density. In this paper, the height of flow channel and the position, arrangement, number and height of the fin which is placed in channel, are changed to get different structures of bi-layer interconnector, and they are applied to three layers SOFC stack. The effects of each structural parameter on the current density are studied by numerical simulation. The results show that, increasing the number of fins and bi-layer interconnector height can make more reactant gas enters the electrode. In addition, compared with the conventional structure, the current density can be increased by the bi-layer interconnector up to 31.256%, and the bi-layer interconnector structure could save n-1 layers of interconnector, which reduces the volume of SOFC stack. Among the five structural parameters, the position of fins has the least influence on temperature distribution and current density, while the arrangement of fins has the highest influence on volume current density, reaching 30%. Using a staggered arrangement and higher bi-layer interconnector can also improve the temperature distribution. • A three-dimensional SOFC stack with bi-layer interconnector was established. • Changing geometry of fins and channel height to get different structures. • Increasing number of fins and channel height improve concentration distribution. • The arrangement of fins has the greatest impact on current density. • Staggered fins and higher bi-layer interconnector reduce the highest temperature. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We show how the quantum hydrodynamical formulation of quantum mechanics converts the nonlocality in the standard wave-like description of quantum systems by an instability of the quantum system, which opens the door to a new way for studying quantum systems based on known methodologies for studying the stability of fluids. As a second result, we show how the Madelung equations describe quantized energies without any external quantization conditions. [ABSTRACT FROM AUTHOR]

The tensile properties of the electroforming deposits with traditional high-concentration sulfate copper are poor, and its tensile strength is only approximately 180 MPa. To improve the mechanical and physical properties of electroforming copper, the influences of copper sulfate concentrations and current densities on the tensile properties of free beads-friction-assisted electroforming copper are investigated. In the experiment, low copper sulfate concentrations of 40, 80 and 120 g/L are selected, and ceramic beads are used to grind the surface of the cathode. The results show that when reducing the copper sulfate concentration or increasing the current density, the tensile strength and elongation ratio can be improved. The electroforming deposit of highest tensile property is obtained with copper sulfate concentration of 80 g/L and current density of 4 A/dm2, and the microhardness is 146.3 HV, the tensile strength is 308.5 MPa and the elongation ratio is 19.6%. Compared with the result of traditional high-concentration sulfate electroforming copper, the tensile strength increases by approximately 70%. Moreover, the fracture section appears dimple fracture, approving the electroforming copper is uniform and dense in microstructure. However, for 40 g/L ultra-low-concentration sulfate electroforming copper, the cathode limit current density is approximately 3 A/dm2, and when the current density increases to 4 A/dm2, the excessive current density increases the degree of concentration polarization. The hydrogen evolution is so serious that the electroforming deposit undergoes hydrogen embrittlement fracture, so the tensile properties decrease. The microhardness is 102.3 HV, the tensile strength is only 130.4 MPa and the elongation ratio is 6.1%. [ABSTRACT FROM AUTHOR]

Improving catalytic activity of cathode with noble metal-free catalysts can significantly establish microbial fuel cells (MFCs) as a sustainable and economically affordable technology. This investigation aimed to assess the viability of utilizing tri-metal ferrite (Co0.5Cu0.5 Bi0.1Fe1.9O4) as an oxygen reduction reaction (ORR) catalyst to enhance the performance of cathode in MFCs. Trimetallic ferrite was synthesized using a sol–gel auto-combustion process. Electrochemical evaluations were conducted to assess the efficacy of as-synthesized composite as an ORR catalyst, employing electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This evaluation revealed that the impregnation of bismuth in the Co–Cu-ferrite structure improves the reduction current response and reduces the charge transfer resistance. Further experiments were conducted to test the performance of this catalyst in an MFC. The MFC with tri-metal ferrite catalyst generated a power density of 11.44 W/m3 with 21.4% coulombic efficiency (CE), which was found to be comparable with commercially available 10% Pt/C used as cathode catalyst in MFC (power density of 12.14 W/m3 and CE of 23.1%) and substantially greater than MFC having bare carbon felt cathode without any catalyst (power density of 2.49 W/m3 and CE of 7.39%). This exceptionally inexpensive ORR catalyst has adequate merit to replace commercial costlier platinum-based cathode catalysts for upscaling MFCs. [ABSTRACT FROM AUTHOR]

Microbial electrolysis cell (MEC) is gaining importance not only for effectively treating wastewater but also for producing hydrogen. The up‐flow microbial electrolysis cell (UPMEC) is an innovative approach to enhance the efficiency, and substrate degradation. In this study, a baffled UPMEC with an anode divided into three regions by inserting the baffle (sieve) plates at varying distances from the cathode was designed. The effect of process parameters, such as flow rate (10, 15, and 20 mL/min), electrode area (50, 100, and 150 cm2), and catholyte buffer concentration (50, 100, and 150 mM) were investigated using distillery wastewater as substrate. The experimental results showed a maximum of 0.6837 ± 0.02 mmol/L biohydrogen at 150 mM buffer, with 49 ± 1.0% COD reduction using an electrode of area 150 cm2. The maximum current density was 1335.94 mA/m2 for the flow rate of 15 mL/min and surface area of 150 cm2. The results showed that at optimized flow rate and buffer concentration, maximum hydrogen production and effective treatment of wastewater were achieved in the baffled UPMEC. Practitioner Points: Biohydrogen production from distillery wastewater was investigated in a baffled UPMEC.Flowrate, concentration and electrode areas significantly influenced the hydrogen production.Maximum hydrogen (0.6837±0.02mmol/L.day) production and COD reduction (49±1.0%) was achieved at 15 mL/min.Highest CHR of 95.37±1.9 % and OHR of 4.6±0.09 % was observed at 150 mM buffer concentration. [ABSTRACT FROM AUTHOR]

Inspired by NG/TiO2 composite reinforcing particles in the Ni–P matrix, an electrochemically assisted electroless deposition method was used to deposit Ni–P–TiO2–NG composite coatings on steel substrates in order to enhance their electrochemical and photocatalytic properties. The effects of current density on the microstructure, surface morphology and phase composition of the coatings were investigated. Statistical analysis based on multifractal formalism shows that the uniformity of the height distribution shows an increasing and then a decreasing trend as the current density increases. The results show that the average hardness reached a maximum value of 966 HV0.1 for the optimum coating obtained at a current density of 4 A dm–2, the corrosion current reached a minimum value of 2.041 × 10–5 A cm–2, with a maximum corrosion potential of –0.281 V vs. SCE. These improvements can be attributed to high phosphorus Ni–P composite coatings with smooth and dense morphology, TiO2/NG nanocomposite impermeability and excellent mechanical properties. In addition, the photocatalytic activity of the Ni–P–TiO2–NG coating gradually increases with increasing current density. [ABSTRACT FROM AUTHOR]

Bearing steel (GCr15) is widely used in key parts of mechanical transmission for its excellent mechanical properties. Electrochemical machining (ECM) is a potential method for machining GCr15, as the machining process is the electrochemical dissolution of GCr15 regardless of its high hardness (>50 HRC). In ECM, NaNO3 solution is a popular electrolyte, as it has the ability to help in the nonlinear dissolution of many metallic alloy materials, making it useful for precision machining. However, due to high carbon content of GCr15, the electrochemical dissolution of GCr15 is unique, and there is always a black layer with high roughness on the machined surface, reducing the surface quality. In order to improve the electrochemical machining of GCr15 with a high surface quality, the surface characteristics of GCr15 in ECM were investigated. The anodic polarisation curve in the NaNO3 electrolyte was measured and electrochemical dissolution experiments were conducted with different current densities. SEM, XRD, and XPS were employed to analyse the surface morphology and composition formed on the machined surface at different current densities. The initial results showed that there were two parts (black part and bright part) formed on the machined surface when a short circuit occurred, and the test results suggested that the black part contained a mass of Fe3O4 while the bright part was composed of mainly Fe and Fe3C. Further investigation uncovered that a black flocculent layer (Fe3O4) always formed in a low current density (32 A/cm2) with high roughness. With the current density increased, the amount of black flocculent layer was reduced, and Fe3C particles appeared on the machined surface. When the current density reached 81 A/cm2, the entire flocculent oxide layer was removed, only some spherical Fe3C particles were inserted on the machined surface, and the roughness was reduced from Ra7.743 μm to Ra1.783 μm. In addition, due to exposed Fe3C particles on the machined surface, the corrosion resistance of the machined surface was significantly improved. Finally, circular arc grooves of high quality were well manufactured with current density of 81 A/cm2 in NaNO3 electrolyte. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigates the surface morphology and microstructure of nickel (Ni) plating and nickel-fluorinated graphene (Ni-FG) composite plating, both produced using a direct current (DC) power supply under standard and supercritical conditions. The findings reveal that the Ni-FG composite plating created under supercritical conditions can incorporate more fluorinated graphene (FG), with the carbon content reaching 0.727 wt%, surpassing the 0.155 wt% found in the plating produced by conventional electrodeposition. The supercritical plating also exhibits improved surface morphology, characterized by a smooth, defect-free surface. The grain size of the plating is notably smaller, averaging 7.39 nm, which is a reduction of over 59.6% compared to other plated layers, with grains predominantly oriented towards the (111) texture. The study focuses on comparing the surface morphology, microstructure, mechanical properties, and electrochemical characteristics of Ni-FG composite plating prepared at various current densities. Results indicate that at a current density of 5 A/dm2, the Ni-FG composite plating displays an exceptionally refined grain structure, with an average grain size of 7.39 nm. This plating layer exhibits excellent wear resistance, with a microhardness value of 772.2 HV0.2, a low coefficient of friction of 0.17, and a minimal wear volume of 1.890 × 107 μm3. Furthermore, the coatings produced at this current density exhibit exceptional corrosion resistance, as indicated by a film resistance (Rcoat) of 13,850 Ω cm2 and an interface resistance (Rct) of 10.96 × 104 Ω cm2 during the electrode oxidation process.

Introduction. Plastic deformation and electric current, acting separately, usually have opposite effects on the deformation behavior and flow stresses in electrically conductive materials. In the case of the combined action of plastic deformation and applied electric current, the result is not pre predictable. The study of the synergistic effect of deformation and electric current can be used for metal forming. Aim of the Study. The study is aimed at demonstrating the existence of impulse current threshold parameters at which the athermal electroplastic effect manifests itself in various materials. Materials and Methods. Tensile tests were performed at various current modes, which exclude the increased contribution of the thermal effect to the reduction of flow stresses – current density and duty cycle. The fractographic features of the fracture surface were studied using raster scanning microscopy. There were found the threshold values of current parameters at which stress jumps associated with the electroplastic effect occur. Results. The influence of the density and duty cycle of the impulse current on the manifestation of the electroplastic effect is shown. Both parameters have threshold values, above which the electroplastic effect becomes observable (at density j jкр ) or athermal (at duty cycle Q Qкр). All types of tension are accompanied by a viscous fracture and void formation, which is most intensively formed, when current is injected. Discussion and Conclusion. In alloys with low electrical resistance, the threshold impulse current density corresponding to the occurrence of the electroplastic effect is higher than in alloys with high electrical resistance. Increasing the duty cycle of the impulse current reduces the temperature of the deformed sample that allows considering the electroplastic effect as athermal.

Supercapacitors' high power density and extended life cycle have drawn a lot of interest in energy storage devices. In this study, different nanostructures of nickel oxide (NiO) and zinc oxide (ZnO) were synthesized using the hydrothermal method by treating the corresponding metal precursors in a high-temperature aqueous solution. The XRD and SEM were used to analyse crystal structure and morphology, respectively. The absorption of ZnO and NiO materials is found to be in the visible range of 300–400 and 200–300 nm, respectively. The band gap of ZnO was calculated as 3.04 eV, while that of NiO was 3.93 eV. The supercapacitor electrode was fabricated on nickel foam with developed nanostructure and carbon materials. The composite ZnO and NiO materials showed an increase in capacitance compared to the bare NiO and ZnO electrodes. This enhancement could be related to improved charge transfer kinetics and increased surface area for electrolyte interaction. Galvanostatic charge–discharge, cyclic voltammetry and electrochemical impedance spectroscopy measurements were conducted to assess the electrochemical efficiency of nanomaterials and their composites. At the current density of 2 A g−1, the specific capacitance of the NiO/ZnO composite is found to be 351.54 F g−1, which is ~2 times of the bare NiO and ~3.34 times of bare ZnO. The maximum energy density of ZnO nanoparticles, NiO nanoflakes and the composite are found to be 3.96, 6.58 and 13.90 Wh kg-1, respectively. The charge storage process is the result of diffusion and redox reactions. This paper explores a binary oxide composites method for creating efficient supercapacitor electrode materials. [ABSTRACT FROM AUTHOR]

This contribution describes the indirect electrochemical oxidation of wastewater laden with bromothymol blue and methyl red dyes using a laboratory-scale electrochemical reactor with a Ti/Ru0.3Ti0.7O2 anode and stainless-steel cathode. The influence of current density, pH, and electrolyte concentrations on the oxidative degradation pattern of the dyes in the wastewater was also investigated by coupling the electrochemical reactor with an Ultraviolet–Visible spectrometer. By indirect oxidation, 97% of the bromothymol blue at 10 mA cm–2 current density and pH 3.0 and 98% of the methyl red at 2 mA cm–2 current density at pH 3.0 were indirectly oxidized in 10 min Initial concentrations of each were 200 ppm. During the degradation of the dyes, electrochemically generated chlorine and hypochlorite ions (OCl)– played pivotal roles. Under the aforementioned ideal circumstances, the minimum energy consumption values for bromothymol blue and methyl red were 0.2025 and 0.0636 kW h m–3, respectively. The anode exhibited an excellent service life for treating dye wastewater, and repeated tests and surface analysis revealed no evident passivation. In this way, a variety of dyes in effluents can be cheaply degraded by electrolyzing with a Ti/Ru0.3Ti0.7O2 anode, utilizing readily available electrolytes and with minimal electricity requirements. [ABSTRACT FROM AUTHOR]

Abstract One crucial objective of this article is to present simplified and accurate approaches to study the current distribution and ground surface potential around the area surrounding an earthed and isolated system in case of a line‐to‐earth fault. The present study is done in the case of uniform and two‐layer soils. Suggested models for calculating the distribution of the earth's surface current density, step, and touch voltages in grounded and isolated systems are presented, discussed, and adapted. The contact and arc resistances of line to ground faulty conductors are considered. Rods and/or grounding grids usually do grounded systems. The impact of both step and touch potentials and current density are investigated in this article. The methods of the calculations are based on the electrical concepts, the charge simulation method, and the imaging procedure for the grounding system. The suggested method can be considered a novel and simple technique for calculating the current distributions of the ground surface during line to ground fault. The results agree with those obtained by others, with the advantage of the proposed algorithm for its ease of application and simplicity. 3‐D dimensions’ contours of the current density and the electric potential on the earth surface around the faulty point are presented in case of homogeneous and two layers’ soil. Finally, this article's novelty is to devise a method for calculating the step and touch potentials and current density around the point of contact of the conductor carrying the electric voltages in the event of faults occurring in the electrical network, whether the network is grounded or isolated. Such faults of electrical networks may cause human hazards.

This study aims to explain the effect of adding the bioactive substance (alpha enzyme) to the electrolyte solution using electrochemical deposition. Through which copper nanoparticles are manufactured, the originality of the research lies in the presence of this addition as a new method in manufacturing nanoparticles in an electrochemical manner, as the alpha-amylase enzyme is extracted from camel saliva, and the product has been diagnosed using (EDX) and scanning electron microscope (FE-SEM) techniques. , Dynamic Light Scattering (DLS) technology, and Zeta potential. The proposed method is an easy, inexpensive, and environmentally friendly method where the alpha enzyme was used as a feedstock at concentrations of (0.25, 0.50, 0.57, and 1) g added to a solution containing the ideal sample obtained through the electrochemical precipitation process before adding the enzyme, as the solution before The addition process contains concentrated sulfuric acid (H2SO4) at concentrations of (20, 30, 40, 50 and 60) g/ml. The regular shape and stable distribution can be observed after the addition compared to the shape of the particles before the addition in terms of shape and size. The process was carried out under constant conditions, including the current. Direct, voltage and temperature, and after the addition process, sulfuric acid was dispensed with, while the process conditions with the addition were at a temperature of 37 degrees Celsius and an incubation period that lasted a full hour before the electrodeposition process was carried out in accordance with the enzyme activity conditions, where a nanosized copper powder of a granular size was obtained. Approximately 44 nanometers. It is worth noting that the nanoparticle size was modulated using the experimental conditions, e.g., pH, reducing step, enzyme amount, or incubation time. This controlled synthesis allows the preparation of CuNP bionanoparticles at Cu 3.13 powder at a concentration of 80 g CuSO4 + 0.50 α-amylase.

A solid oxide fuel cell (SOFC) is a clean and very efficient electrochemical conversion device, which generates electricity directly from fuel electrochemical oxidation. In this paper, a three dimensional numerical model has been developed in order to analyse the role of some thermophysical and morphological parameters on the performance of the SOFC cell. In particular, we studied the effect of the variation of permeability of the electrodes: fuel distribution, ionic and electric current density, pressure and diffusion flux are analyzed and compared. The volume fraction of the ionic and electronic phase in the electrodes is studied using a parametric study. It was shown that the current density enhanced by decreasing the permeability, up to a defined value, and it diminished with very small permeability. A remarkable influence of pressure and diffusion of species on the performance of the cell, with the variation of permeability, has been recognized. Varying the permeability in the active layer of electrodes has a large impact on the current density, connected to the volume fraction of ionic phase. This study permits to comprehend the relationship between the performance and microstructure of SOFCs. Meanwhile, it furnishes theoretical guidance for an optimum design of the electrode permeability. • A three-dimensional model of a single SOFC is developed using CFD method. • Varying the permeability of electrode components affects the cell performance. • The impact of volume fractions for different permeabilities is studied. • It is concluded that there is an optimum design of the electrode permeability. [ABSTRACT FROM AUTHOR]

AbstractPhysical measurements of the normal state of an unconventional or high-temperature superconductor in the zero-temperature limit can provide vital information on the nature of the electronic ground state from which the superconductivity emerges. Viable routes to fully suppress the superconductivity include the application of magnetic fields stronger than the upper critical field Hc2 or current densities larger than the critical current density Jc. In high-Tc superconductors, Hc2 is typically higher than the available field strengths, while high currents can often create large heating effects that cause irreparable damage to the sample. Here, we present a technique that combines intense current pulses with high magnetic fields to fully suppress the superconductivity of a candidate high-Tc superconductor while keeping both J and μ0H below their critical values. Two adaptable circuit designs are presented with negligible stray field or self-heating effects (below a critical current value). As a proof of principle, we apply the technique to a high-Tc cuprate with nominal μ0Hc2 ∼ 36 T and demonstrate the suppression of superconductivity down to T/Tc ≤ 0.1 in a field strength of just 24 T. Further applications of this dual technique are also discussed. [ABSTRACT FROM AUTHOR]

Some planar and non‐planar clarenes have been studied using maps of magnetically induced quantum‐mechanical current density and tools from differential topology to assess their magnetic response in connection with recent results by Du and Wang. Bond current strengths have been computed to estimate quantitative measures. Isosurfaces of the divergence of induced Lorentz force density have been shown to provide useful additional criteria, especially in the case of non‐planar clarenes. [ABSTRACT FROM AUTHOR]

It is important to find the estimation methodology with the highest accuracy in order to determine the parameters of water disinfection and to provide the most ideal disinfection. In this study, the usability of artificial neural networks in predicting response disinfection efficiency in electrochemical water disinfection processes was investigated. An artificial neural network model was developed using a total of 17 data sets and Response Disinfection Efficiency values were estimated from the model. Current density, treatment time and interelectrode spacing values are defined as input parameters in the network model, which has a multilayer perceptron architecture with 10 neurons in its hidden layer. The coefficient of determination value for the developed model was 0.98682 and the average deviation rate was −0.1%. The study findings showed that neural networks are an ideal tool that can be used to predict response disinfection efficiency in electrochemical water disinfection processes. [ABSTRACT FROM AUTHOR]

Electrochemical study of the mechanism of dimethylsulfoxide electrooxidation on a platinum electrode in acidic and alkaline solutions is carried out. On the stationary anodic polarization curves taken in acidic and alkaline dimethylsulfoxide solutions, the oxidation currents preceded those measured in the supporting electrolyte. By the analyzing of linear segments of anodic voltammograms, the coefficients of the Tafel equation are determined. This allowed choosing the current density range and conditions for the dimethylsulfoxide electrooxidation on the platinum electrode. The electrolysis was carried out at controlled current density in electrolyzers both with unseparated compartments and the anodic and cathodic compartments separated with MK-40, MA-40 membranes and a MF-4SK fluoropolymer sulfocationite membrane. The high electrical conductivity and selectivity of the membranes provided good performance of the electrolysis process and obtaining of high-purity final product. Raman spectroscopy and gas chromatography–mass spectrometry confirmed that the products of dimethylsulfoxide electrooxidation in the acidic solution are dimethylsulfone and dimethylsulfoxide; in alkaline solution, the dimethyl sulfone and sodium methanesulfonate. The method of quantum-chemical calculations showed good adsorption of dimethylsulfoxide molecules at platinum within the frames of the cluster model. It is shown that the dimethylsulfoxide formation at the platinum electrode surface at high current densities occurs by the radical-ion mechanism, involving breaking of the C–S bond. Based on the experimental results obtained, a scheme for the dimethylsulfoxide electrochemical oxidation at platinum is proposed. [ABSTRACT FROM AUTHOR]

The formation of amorphous thin surface layers of nanoporous Ge with various morphologies during the low-energy high-dose implantation by metal ions of different masses, namely 63Cu+, 108Ag+, and 209Bi+, on single-crystal c-Ge substrates was experimentally demonstrated using high-resolution scanning electron microscopy. The structure of the obtained nanoporous Ge layers was studied using backscattered electron diffraction. Under irradiation with low-energy ions, such as 63Cu+ and 108Ag+, needle-like nanostructures constituting a nanoporous thin Ge layer form on the surface of c-Ge. However when employing havier 209Bi+, the implanted layer consists of densely packed nanowires. At high ion-irradiation energies, the morphology of the thin surface layers of nanoporous Ge undergoes a sequential transformation in shape from three-dimensional reticulated to spongy as the mass of the implanted ions increased. Such a spongy structure was formed by sparse individual intertwining nanowires. The general potential mechanisms for pore formation in Ge during low-energy high-dose ion implantation are discussed, including the cluster–vacancy mechanism, local thermal microexplosion, and localized heating accompanied by surface melting with effective sputtering. [ABSTRACT FROM AUTHOR]

Progress in locating the X‐line on the magnetopause beyond the atypical due south interplanetary magnetic field (IMF) condition is hampered by the fact that the global plasma and field spatial distributions constraining where reconnection could develop on the magnetopause are poorly known. This work presents global maps of the magnetic shear, current density and reconnection rate, on the global dayside magnetopause, reconstructed from two decades of measurements from Cluster, Double Star, THEMIS and MMS missions. These maps, generated for various IMF and dipole tilt angles, offer a unique comparison point for models and observations. The magnetic shear obtained from vacuum magnetostatic draping is shown to be inconsistent with observed shear maps for IMF cone angles in 12.5° ± 2.5° ≤ |θco| ≤ 45° ± 5°. Modeled maximum magnetic shear lines fail to incline toward the equator as the IMF clock angle increases, in contrast to those from observations and MHD models. Reconnection rate and current density maps are closer together than they are from the shear maps, but this similarity vanishes for increasingly radial IMF orientations. The X‐lines maximizing the magnetic shear are the only ones to sharply turns toward and follow the anti‐parallel ridge at high latitude. We show the behavior of X‐lines with varying IMF clock and dipole tilt angles to be different as the IMF cone angle varies. Finally, we discuss a fundamental disagreement between X‐lines maximizing a given quantity on the magnetopause and predictions of local X‐line orientations. Key Points: Global dayside reconstructions of the magnetic reconnection rate, magnetic shear and current density is proposed from in situ measurementsThe interplanetary magnetic field cone angle is a key parameter controlling these spatial distribution and their evolution with the IMF orientation and dipole tiltA parametric survey shows how to distinguish candidate X lines maximizing globally these distributions [ABSTRACT FROM AUTHOR]

This paper simulated the optimum solar cell power conversion efficiency-based planar solar surface morphology with various solar cell absorber structures. The spectral light intensity, reflected, absorbed, and transmission coefficients versus wavelength band spectrum varied from 300nm to 1300nm through the visible to near-infrared regions. The optimum solar cell performance parameters or key parameters are studied with different solar cell structure designs based on different surface contact and back contact layers. Cumulative generation current, cumulative electron–hole pair generation rate and electron–hole pair generation rate are clarified versus substrate depth for various solar cell structure designs. The absorbed current in substrate is optimized for various solar cell structure designs. Maximum power voltage and current are also optimized for the proposed solar cell structure design. The effective solar cell power efficiency is also demonstrated based on the optimized maximum power current and maximum power voltage. [ABSTRACT FROM AUTHOR]

During the normal laying and operation of a three-core umbilical cable, AC current can easily lead to AC electrochemical corrosion on the outer surface of the steel tube. To explore the electrochemical corrosion mechanism and the factors affecting the three-core umbilical cable, this paper optimizes the internal induced potential calculation method for three-core umbilical cables. It analyzes the changes in the characteristics of the induced potential and explores the variations in the density of induced current under different conditions. The research results show that by optimizing the calculation method for the induction potential of the umbilical cable's steel pipe, for the electromagnetic significance of the smallest repeating unit, the induction potential on the steel pipe's surface exhibited a cyclic change. The peak part of the induction potential is most likely to experience electrochemical corrosion. Additionally, reducing the radius of the outer insulation aperture of the steel pipe and improving the conductivity of seawater will increase the density of the induced current in the insulation aperture, thereby increasing the risk of electrochemical corrosion. As the cable pitch and AC frequency increase, the current density in the steel pipe pores will also rise. [ABSTRACT FROM AUTHOR]

The effluent from the oil drilling site is a complex mixture of hazardous chemicals that causes environmental impacts on its disposal. The treatment of oil drill-site wastewater has not been explored much, and understanding its characteristics and optimizing the treatment process are required. In the present study, we have optimized the electrocoagulation process with aluminum electrodes for drill-site wastewater treatment. A multi-level factorial center composite design using response surface methodology is applied to optimize the effect of current density (CD), pH, and inter-electrode distance (IED) on chemical oxygen demand (COD) removal. The increasing current density shows a significant increase in COD removal, and a similar trend was observed with a decreased pH. It was found that with current density and inter-electrode distance, the maximum COD removal achieved was 70% at the CD of 19.04 mA cm−2 and IED 2.6 cm. By varying pH and current density, the COD removal reached up to 90% at pH 6 and CD 19.04 mA cm−2. The study shows that the current density is the dominant factor for the process's energy consumption and operating cost, followed by pH. This study's findings could be effectively used to develop large-scale treatment processes through electrocoagulation. [ABSTRACT FROM AUTHOR]

One crucial objective of this article is to present simplified and accurate approaches to study the current distribution and ground surface potential around the area surrounding an earthed and isolated system in case of a line‐to‐earth fault. The present study is done in the case of uniform and two‐layer soils. Suggested models for calculating the distribution of the earth's surface current density, step, and touch voltages in grounded and isolated systems are presented, discussed, and adapted. The contact and arc resistances of line to ground faulty conductors are considered. Rods and/or grounding grids usually do grounded systems. The impact of both step and touch potentials and current density are investigated in this article. The methods of the calculations are based on the electrical concepts, the charge simulation method, and the imaging procedure for the grounding system. The suggested method can be considered a novel and simple technique for calculating the current distributions of the ground surface during line to ground fault. The results agree with those obtained by others, with the advantage of the proposed algorithm for its ease of application and simplicity. 3‐D dimensions' contours of the current density and the electric potential on the earth surface around the faulty point are presented in case of homogeneous and two layers' soil. Finally, this article's novelty is to devise a method for calculating the step and touch potentials and current density around the point of contact of the conductor carrying the electric voltages in the event of faults occurring in the electrical network, whether the network is grounded or isolated. Such faults of electrical networks may cause human hazards. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Physics is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the realm of sustainable and environmentally friendly "green-hydrogen" fuel demand, water electrolysis stands as a pathway of hope for the extraction of renewable hydrogen. However, the durability and efficiency of electrocatalysts have been a major challenge in this process, owing to factors like the high costs of noble catalysts (Pt, Ir, Ru, etc.) and their limited stability. Layered Nickel-iron double hydroxides (NiFe-LDH) have shown potential as low-cost and efficient electrocatalysts because of their suitable electronic configuration and distinguished orbital confinement. However, their durability In the realm of sustainable and environmentally friendly "green-hydrogen" fuel demand, water electrolysis stands as a pathway of hope for the extraction of renewable hydrogen. However, the durability and efficiency of electrocatalysts have been a major challenge in this process, owing to factors like the high costs of noble catalysts (Pt, Ir, Ru, etc.) and their limited stability. Layered Nickel-iron double hydroxides (NiFe-LDH) have shown potential as low-cost and efficient electrocatalysts because of their suitable electronic configuration and distinguished orbital confinement. However, their performance and durability in corrosive alkaline water at high current density remain limited. In this regard, one can make the nano-composites of this NiFe-LDH with high electronic conductivity materials and layered structures like VSe 2. With this motivation, this work presents a novel electrocatalyst, NiFe-LDH, supported with VSe 2 nanosheets ( V Se 2 / NiFe − LDH), designed to address these challenges and enhance water splitting efficiency. Experimental results demonstrate that the heterostructure synergistically reduces charge transfer resistance, increases exposure of active sites, and enhances oxygen gas evolution ability. Consequently, the V Se 2 / NiFe − LDH electrocatalyst demonstrated superior sustainability, maintaining an elevated current density (500 mA cm − 2 ) for over 50 h of continuous electrolysis without noticeable degradation. This research opens up new possibilities and shows that nano-compositing can be a good option for achieving efficient and durable electrocatalysts in alkaline water splitting, thereby contributing to sustainable hydrogen production. [Display omitted] • Facile hydro/solvothermal preparation of composites of NiFe-LDH and VSe 2. • Enhanced Oxygen and Hydrogen evolution were observed. • Decreased charge transfer resistance was noticed. • Durable up to about 50 h for overall water splitting at a high current density of 500 mA cm − 2. [ABSTRACT FROM AUTHOR]

Transcranial direct current stimulation (tDCS) is a noninvasive method of brain modulation that is increasingly used to treat neuropsychiatric disorders and enhance cognitive capacity. Computational modeling provides a valuable tool for designing and analyzing current stimulation devices for the treatment of neurological disorders and diseases. Here we use a three-dimensional finite element model (FEM), we constructed a simulation model and verified the results by reference to experimental data. A multi-layer sponges' design with step conductivity was presented to reduce the crowded current density distribution and investigated the influencing factors, we identified relevant factors and used them to optimize the sponge. We optimized the sponge design by optimizing the sponge's stepped conductivity and the thickness. We found that by using the stepped sponge design, the model could meet the impedance matching between the last sponge layer and the skin surface. [ABSTRACT FROM AUTHOR]

Background: Transcranial electrical stimulation (tES) generates an electric field (or current density) in the brain through surface electrodes attached to the scalp. Clinical significance has been demonstrated, although with moderate and heterogeneous results partly due to a lack of control of the delivered electric currents. In the last decade, computational electric field analysis has allowed the estimation and optimization of the electric field using accurate anatomical head models. This review examines recent tES computational studies, providing a comprehensive background on the technical aspects of adopting computational electric field analysis as a standardized procedure in medical applications. Methods: Specific search strategies were designed to retrieve papers from the Web of Science database. The papers were initially screened based on the soundness of the title and abstract and then on their full contents, resulting in a total of 57 studies. Results: Recent trends were identified in individual- and population-level analysis of the electric field, including head models from non-neurotypical individuals. Advanced optimization techniques that allow a high degree of control with the required focality and direction of the electric field were also summarized. There is also growing evidence of a correlation between the computationally estimated electric field and the observed responses in real experiments. Conclusions: Computational pipelines and optimization algorithms have reached a degree of maturity that provides a rationale to improve tES experimental design and a posteriori analysis of the responses for supporting clinical studies. [ABSTRACT FROM AUTHOR]

We herein report the fabrication of mixed oxide Cu2O/CuO nanowire electrodes through the anodisation of Cu-mesh. These synthesised electrodes are then coated with a protective carbon layer to enhance hydrogen production via photoelectrochemical (PEC) water splitting. Our study addressed Cu2O/CuO nanowire surface modification via anodisation voltage adjustment and analyzed annealing effects on carbon-coated electrodes under controlled temperatures in a nitrogen environment. Optimisation at 5V anodisation potential yielded enhanced photocurrents, with the Cu2O/CuO mixed phase proving crucial for improved PEC activity. XRD, SEM and TEM analyses were conducted to evaluate the structural and morphological characterisation of the synthesised samples. A thin carbon coated sample annealed at 550 °C enhances the photoelectrochemical efficacy of Cu2O nanowires, obtaining a peak photocurrent density of ∼4 mA cm−2 at 0 V (vs. RHE). In contrast, as prepared pristine optimised Cu2O/CuO nanostructured electrodes deliver a photocurrent density of ∼ 2 mA cm−2 at 0 V (vs. RHE) under AM 1.5G light solar irradiation with an intensity of 100 mWcm-2. The Mott–Schottky analysis exhibits p-type semiconducting nature of carbon coated Cu2O/CuO electrodes. The photocurrent stability test alsoconfirms that carbon coated Cu2O/CuO electrodes are one of the best candidates for improving the photoelectrochemical water splitting reaction. [ABSTRACT FROM AUTHOR]

This study focuses on the design and development of reduced graphene-oxide-anchored Co3O4 nanotubes. The graphene sheets were decorated with Co3O4 nanotubes using a simple one-pot, solution-phase process. Morphological examination revealed structures, such as nanotubes. The produced nanotubes had an average length of 1 μm, width of 312 nm, and diameter of 80 nm. The presence of Co, O, and C in the synthesized nanotubes was verified by EDAX analysis. The XRD diffraction pattern confirmed the cubic structure of the Co3O4 nanotubes. The Raman spectra indicate the existence of active modes in the obtained Co3O4. TGA confirmed that the synthesized rGO-Co3O4 was stable up to 850 °C. The pore size of the developed rGO/Co3O4 nanotubes was determined to be 3.539 nm, as observed using BET microscopy. The performance of the supercapacitor was tested in a 2 M KOH electrolyte after the rGO/Co3O4 nanocomposite electrode was fabricated. It shows pseudocapacitive performance and leads to a maximum specific capacitance (Csp) of 457 F/g in CV for a scan rate of 3 mV/s and 462 F/g and at a current density (CD) of 1 mA/g. [ABSTRACT FROM AUTHOR]

• The analytical solutions of the current and energy flux of the thermoelectric half-plane under periodic contact are obtained. • The influence of topography and material on the contact response is discussed. • The stress distribution of thermoelectric and elastic materials under partial and full contact conditions is revealed. • The influence of load level on contact behavior is revealed. The solution of the contact problem with multiple contact areas between a thermoelectric device and a surface is crucial for the design and optimization of thermoelectric devices. This study focuses on the contact problem of a thermoelectric half-plane and a rigid solid with periodic wavy surfaces. The interface profile is represented by a periodic function, which is likely more accurate when addressing periodic structures compared with an assumed flat or smooth interface. The exact contact areas between the thermoelectric device and the rigid solid are not predetermined but need to be calculated as part of the analysis. To tackle the nonlinear problem caused by waviness and thermoelectric effects, the integral transformation method is used to simplify the stated problem into three singular integral equations (SIEs) with the Hilbert kernels. The equations in terms of the interface normal current density and interface normal energy flux are transformed into the Cauchy SIEs of the first type through variable transformation, and solved analytically. Two special cases are checked with the thermoelectric load being zero or the periodic region being infinite, and the analytical solutions obtained are consistent with the classical results. The equation in terms of the interface normal contact stress is solved numerically by the collocation methods. The numerical results show that the interface stress of the material can be changed effectively by adjusting the thermoelectric load, thus reducing the thermoelectric-mechanical contact damage of the material. The present work may provide a benchmark for studying more complex multi-area surface/interface contact problems of thermoelectric materials and structures. [ABSTRACT FROM AUTHOR]

In this research, a three-dimensional model has been developed in COMSOL Multiphysics software for numerical simulation to assess the high temperature proton exchange membrane fuel cell performance across various parameters. The results of the simulation and the data from experiments correspond closely when the values of the temperature, the thicknesses of the electrode layer and the membrane are 453.15K, 50e-6m and 100e-6m, respectively. Polarization curves at different cell temperatures, operating pressures, different porosities of gas diffusion layer, membrane conductivities, membrane thicknesses and porous electrode thicknesses are examined. The obtained results indicate that the fuel cell performance decreases when the cell runs at temperatures from 393.15K to 453.15K. Moreover, it is found that the cell performance is improved when the gas diffusion layer porosity increases from 0.1 to 0.6. Furthermore, the investigation of the fuel cell thickness membrane effect shows that a thinner membrane of 25e-6m gives the best performance. The simulation using the present developed model can be useful for optimization of the cell design and the operating conditions. [ABSTRACT FROM AUTHOR]

The effects of electro-pulse on microstructure and mechanical properties of Al-Cu-Mn-Zr-V alloy were investigated, and the ageing mechanism was analyzed. As the current density increases, the size and quantity of precipitates gradually transit from continuous aggregation to dispersion at grain boundaries, and the mechanical properties are improved. When the current density is 15 A·mm−2, the precipitates are smallest and the mechanical properties are best. The tensile strength is 443.5 MPa and the elongation is 8.1%, which are 51.7% and 42.1% higher than those of conventional ageing treatment, respectively. Once the current density exceeds 15 A·mm−2, the precipitates will increase again and gather at grain boundaries, and the mechanical properties also decrease. An additional electrical free energy arising from an electro-pulse provides thermodynamic and kinetic conditions for the ageing precipitation of second phases. The electro-pulse can enhance the ageing diffusion coefficient, being improved by 34 times for 15 A·mm−2. The electro-pulse improves the nucleation rate and decreases the critical nucleation radii of second phases. However, it also accelerates the grain growth, making the second phases become coarse. An electro-pulse with a current density of 15 A·mm−2 can rapidly nucleate the second phase at 463 K while the precipitates are relatively small after growth. [ABSTRACT FROM AUTHOR]

Electrochemical machining (ECM) presents numerous applications in the production of aero-engine components. The effects of current density on surface quality during ECM of René 88DT in NaCl-ethylene glycol and NaNO3-aqueous solutions was investigated here. The results indicated that the René 88DT surface has lower sensitivity to current density and more homogeneous electrochemical dissolution in NaCl-glycol solution than in NaNO3-aqueous solution, which results in the suppression of stray corrosion and consistently high surface quality regardless of current density. These strengths are attributed that C2H5O2- and Cl- ions replace OH– ions and combine with alloy ions to form solubles and complexes, which prevent the formation of obstructive passive film, oxide layer, and insoluble electrolytic products. The electrochemical dissolution model in two solutions was established. Furthermore, the high tensile strength and precision machinability of René 88DT in NaCl-glycol solution were also demonstrated.

There is high interest in the recovery of phosphorus (P) from wastewater through crystallization processes. However, the addition of chemical reagents (e.g., sodium hydroxide) to raise the pH may result in high treatment costs and increased concentrations of undesired metal ions (e.g., sodium). As an alternative, in this research we considered electrochemical mediated precipitation at low current densities (0.4–1.2 A m−2) without using chemical reagents. For that purpose, a two-chamber electrochemical system was operated in batch for treating denitrified swine effluent (48 mg P L−1). By applying current at 1.2 A m−2, and targeting pH 11.5, a maximum P removal rate of 33.4 mmol P (L·d−1) was obtained while the P removal efficiency was above 90 %. New solids that formed mostly remained suspended in the catholyte. Before discharge, the catholyte effluent was recirculated to the anodic compartment to neutralize the pH, achieving a final pH of 6.4 ± 0.1. Chlorine (Cl2) production in the anodic compartment was favored by a small anode surface and a high initial pH of the catholyte. Although the production of chlorine achieved was limited (the highest concentration was 8.6 ± 0.1 mg Cl2 L−1) these findings represent a new opportunity for the recovery and onsite use of this side-product. Electrochemical impedance spectroscopy tests confirmed that the deposition of solids inside the cathodic compartment during the experimental period was limited. Membrane analysis revealed significant scaling of carbonate compounds. The electrochemical treatment described above was shown as a promising alternative to sodium hydroxide and sulfuric acid dosage for pH adjustment when crystallizing phosphate salts.