Electrode Rod Research Articles

Suitability of cyclic voltammetry for the measurement of sodium borohydride (NaBH4) in a solution of Cr(VI)/organic compounds/NaBH4

ABSTRACT Cr(VI) reduction by NaBH4 enhanced by organic compounds has been proven to be an effective method. The effort for optimized and efficient application of the method was the reason for the determination of residual NaBH4 in the Cr(VI)/organic compounds/NaBH4 reduction system for reducing agent dosage efficiency. This work showed a suitable detection of NaBH4 standard samples using Pt and Au as working electrode, respectively, and graphite rod as an auxiliary electrode and Ag/AgCl as a reference electrode. In the presence of organic compounds (acetate, citrate, and EDTA), interference was observed in the NaBH4 measurement on Pt electrode making it an unsuitable method for NaBH4 measurement in the presence of organic compounds. As the Au plate electrode was used as a working electrode, NaBH4 solutions measurement in the presence of organic compounds (acetate, citrate and EDTA) by peaks at −0.55 V was found to be affected by the coexisting organic compounds. However, no significant interference of the aforementioned organic compounds was observed at the −0.27 V peak values. The presence of Cr(VI) coexisting with NaBH4 was found to interfere with the NaBH4 measurement using both working electrodes, with a strong correlation between Cr(VI) concentration and the peak values obtained at 0.27 V of Au electrode.

Microstructure and mechanical properties of Co31.5Cr7Fe30Ni31.5 high-entropy alloy powder produced by plasma rotating electrode process and its applications in additive manufacturing

Microstructure and mechanical properties of feedstock powders critically determine the quality of additive manufacturing (AM). The present study employs a plasma rotating electrode process (PREP) to produce non-equiatomic Co31.5Cr7Fe30Ni31.5 high-entropy alloy (HEA) powders and examines variations of their microstructure and mechanical properties with powder particle size in the range of 20–106 μm. It finds that the powders possess smooth surfaces, good sphericity, and equiaxed polycrystal grains under PREP electrode rod arc speed of 32000 r/min and main arc current of 760 A. A stable FCC structure is maintained regardless of the powder particle size. Moreover, the nano-hardness of the powders generally decreases with the increase of powder particle size except for that of 50–75 μm, which is positively correlated with the change of the grain size. The finest grain size is present for powders with particle sizes of 50–75 μm, which possess the highest average nano-hardness and reduced elastic modulus. Bulk alloys fabricated by cold spray (CS) and laser cladding (LC) AM maintain the FCC structure. The CSAM bulk alloy shows early brittle fracture due to the presence of pores and prior particle boundaries resulting from insufficient plastic deformation of the powder particles. The LCAM bulk alloy presents good tensile properties with the ultimate tensile strength (UTS) and elongation to failure being 481.2 MPa and 35.9%, respectively, which can be attributed to the good cohesion and grain characteristics. The present study shall provide the field of AM with useful information in the applications of non-equiatomic PREP HEA powders.

High-Quality Spherical Silver Alloy Powder for Laser Powder Bed Fusion Using Plasma Rotating Electrode Process.

The plasma rotating electrode process (PREP) is an ideal method for the preparation of metal powders such as nickel-based, titanium-based, and iron-based alloys due to its low material loss and good degree of sphericity. However, the preparation of silver alloy powder by PREP remains challenging. The low hardness of the mould casting silver alloy leads to the bending of the electrode rod when subjected to high-speed rotation during PREP. The mould casting silver electrode rod can only be used in low-speed rotation, which has a negative effect on particle refinement. This study employed continuous casting (CC) to improve the surface hardness of S800 Ag (30.30% higher than mould casting), which enables a high rotation speed of up to 37,000 revolutions per minute, and silver alloy powder with an average sphericity of 0.98 (5.56% higher than gas atomisation) and a sphericity ratio of 97.67% (36.28% higher than gas atomisation) has been successfully prepared. The dense S800 Ag was successfully fabricated by laser powder bed fusion (LPBF), which proved the feasibility of preparing high-quality powder by the "CC + PREP" method. The samples fabricated by LPBF have a Vickers hardness of up to 271.20 HV (3.66 times that of mould casting), leading to a notable enhancement in the strength of S800 Ag. In comparison to GA, the S800 Ag powder prepared by "CC + PREP" exhibits greater sphericity, a higher sphericity ratio and less satellite powder, which lays the foundation for dense LPBF S800 Ag fabrication.

Axle Counter Grounding System on The PPI Madiun Railway Using the Wenner Method

Axle counter is a railway detection equipment producing wave frequencies to count the number of axles passing over the track. The existence of a mismatch between the initial and final count numbers usually leads to a red signal and this can prevent the formation of a travel route. The components of axle counter are often damaged by lightning strikes both directly and through the distribution of excessive currents due to a poor grounding system. However, these excessive currents can be safely grounded without damaging the components through the application of a good grounding system. Therefore, this research aimed to plan an effective grounding system to anticipate the incidents using the Wenner method. Some requirements such as soil type, depth, and electrode rod diameter were used in the process to determine the appropriate resistance value. The design was made based on the simulations that closely resembled real field conditions using Aspix software and grounding resistance values were also measured directly on the field to determine the discrepancies between the planning and actual conditions.

Dry reforming in a dielectric barrier discharge reactor with non-uniform discharge gap: Effects of metal rings on the discharge behavior and performance

The application of dielectric barrier discharge (DBD) plasma reactors is promising in various environmental and energy processes, but is limited by their low energy yield. In this study, we put a number of stainless steel rings over the inner electrode rod of the DBD reactor to change the local discharge gap and electric field, and we studied the dry reforming performance. At 50 W supplied power, the metal rings mostly have a negative impact on the performance, which we attribute to the non-uniform spatial distribution of the discharges caused by the rings. However, at 30 W supplied power, the energy yield is higher than at 50 W and the placement of the rings improves the performance of the reactor. More rings and with a larger cross-sectional diameter can further improve the performance. The reactor with 20 rings with a 3.2 mm cross-sectional diameter exhibits the best performance in this study. Compared to the reactor without rings, it increases the CO2 conversion from 7% to 16 %, the CH4 conversion from 12% to 23%, and the energy yield from 0.05 mmol/kJ supplied power to 0.1 mmol/kJ (0.19 mmol/kJ if calculated from the plasma power), respectively. The presence of the rings increases the local electric field, the displaced charge and the discharge fraction, and also makes the discharge more stable and with more uniform intensity. It also slightly improves the selectivity to syngas. The performance improvement observed by placing stainless steel rings in this study may also be applicable to other plasma-based processes.

The grounding resistance improvement of distribution substation using multiple rods and wood charcoal as soil treatment

The grounding system plays the important role in securing the electric power system. Low grounding resistance ensures the proper operation of the grounding system. The lower the grounding resistance value, the easier current flow through the earth without any obstacles then prevents equipment from being damaged or causing the injury of personnel. According to the PUIL 2000 standard, grounding resistance should be less than 5Ω. Methods that can be performed to reduce grounding resistance are increasing the length and diameter of the grounding rod, using multiple rods, and treating the soil to reduce its resistivity. In this study, we would like to improve the grounding system of the KA2317 distribution substation located at Mertasari, Jimbaran in South Kuta, Bali which has a grounding resistance of 8.1Ω (more than 5Ω). The method that was applied in this study was grounding improvement by adding an electrode rod and adding wood charcoal to reduce soil resistivity. At the end of the study, grounding resistance can be reduced from 8.1Ω to 1.9 Ω or improved by 76.6%.

Highly sensitive non-enzymatic glucose sensor based on CoCu@MC derived from CoCu/melamine cyanurate superstructures

Non-enzymatic glucose detections have attracted more and more attentions with the development of electrochemical catalysts. Herein, Co2+ and Cu2+ are introduced into the hexagonal prism of melamine cyanurate, and nitrogen-doped carbon seaweed-like nanosheets ([email protected]) are synthesized through pyrolysis. [email protected] shows superior electrochemical catalytic activity for glucose oxidation with high sensitivity (1.489 μA μM−1 cm−2), low detection limit (0.34 μM) and wide linear range (1 μM–1.25 mM). Also, [email protected] demonstrates excellent application potential for glucose detection in artificial sweat with good conductivity, fast electron transfer, and high selectivity, which result from CoCu bimetal composites and seaweed-like carbon nanostructures. The glassy carbon electrode coated with [email protected] was used as the working electrode along with Ag/AgCl as the reference electrode and carbon rod as the counter electrode. The findings above will provide a general methodology to design and synthesize different carbon nanostructures through the addition of different transition metal cations.

Cross-hole electrical resistivity tomography as an aid in monitoring marine gas hydrate reservoirs for gas recovery: an experimental simulation study

SUMMARY The in situ reservoir status monitoring plays a critical role in natural gas hydrate resource production. Considering the complexity of the field environment, a simulation framework for monitoring gas hydrates with cross-hole electrical resistivity tomography (CHERT) was developed to monitor the hydrate distribution during hydrate formation and dissociation. The simulation study comprised both numerical and physical experiments. The optimal CHERT array was designed through a numerical experiment. The effect of applying CHERT was verified through a physical experiment (a high-resistivity medium and hydrate formation experiment). The results show that improper electrode layouts will lead to varying degrees of low amplitude and blur boundary. An optimal CHERT array of a 100-mm electrode rod spacing, 8-mm electrode ring spacing and 48 electrode rings was obtained. The inversion results obtained using this CHERT array scheme can easily distinguish the distribution of high-resistivity targets and yield satisfactory results in hydrate formation experiments. These findings guarantee data processing and interpretation for applying CHERT in gas hydrate experiments and fields.

Bulky Thiolate-Protected Silver Nanocluster Ag 213 (Adm-S) 44 Cl 33 with Excellent Electrocatalytic Performance toward Oxygen Reduction

Bulky Thiolate-Protected Silver Nanocluster Ag ₂₁₃ (Adm-S) ₄₄ Cl ₃₃ with Excellent Electrocatalytic Performance toward Oxygen Reduction

Effect of Non-Stoichiometry on Magnetocaloric Properties of HoB2Gas-Atomized Particles

We fabricate gas-atomized particles by inductively melting electrode rods of HoB2-x (x = -0.3, 0, 0.3, and 1.0) and investigate the effect of non-stoichiometry on the phase fraction, microstructure, and physical properties. Shifting the stoichiometric ratio of the electrode rod to the B (Ho)-rich side increases HoB4 (Ho) phase in the resulting atomized particles. Even if the atomized particles contain 15-20 weight percent (wt.%) of the impurity phase, the influence of which on the physical properties is less severe: the maximum value of the magnetic entropy change is only reduced by 10% compared to HoB2.0 particles. We further find that the ductile Ho phase exists so as to fill the space between the brittle HoB2 phases in the atomized particles, which may be beneficial to the mechanical properties of the particles. Our findings suggest that it would be better to use the Ho-rich electrode rods than the stoichiometric ones to produce HoB2-x particles with more suitable properties as a magnetic refrigerant for magnetic refrigeration systems.

Influence of Working Surface Temperature on Area Effect in Electrical Discharge Machining Process

In this paper, we discuss the effects of working surface temperature on the material removal rate and tool electrode wear rate in sinking electrical discharge machining (EDM) process in order to clarify machining phenomena referred to as the area effect. First, the material removal rate, tool electrode wear rate and effective discharge frequency were measured for a 5mm-square rod tool electrode, and measured results were compared with those for 10mm-square rod tool electrode and 15mm-square rod tool electrode. Although the area effect is conventionally explained as the effect of discharge frequency, the measured results could not be explained in terms of only the dischargef requency. Then, the material removal rate and tool electrode wear rate for butt machining were compared with those of sinking machining, and the working surface temperature of the tool electrode were estimated using the measured temperature. It was found that the material removal rate and tool electrode wear rate are affected not only by the discharge frequency but also by the working surface temperature. It was also found that the tool electrode wear rate in a small working area can be reduced by lowering the working surface temperature.

Self-diagnosis and High-flashover-strength Electroluminescence Coatings

In high-voltage power equipment, insulation defects are probably generated during the production, assembly, and operation processes, which degrade the insulation materials and even cause failure under electrical stresses. As a result, various detection and diagnosis methods for insulation status have been developed to discover potential defects in equipment, but extra testing devices are usually required. Insulation materials with special stimulus–response performance, as an example, luminescence under the stimulation of intensified electric field or temperature induced by insulation defects, can be developed to realize self-detection and diagnosis of these defects. In this article, a self-diagnosis composite coating was prepared by filling electroluminescence zinc sulfide (ZnS) fillers into polydimethylsiloxane (PDMS). Two kinds of typical electrode configurations, namely, rod plane and needle plane, were processed to examine the luminescence characteristics of composite coating. The influence of the composite coating on flashover characteristics was also investigated. Experimental results indicated that ZnS composite coating exhibits obvious luminescence under relatively low voltage, and its luminance increases with electric field and ZnS content, which can effectively realize the self-detection and diagnosis function. Moreover, the composite coating can effectively improve the ac/dc surface flashover voltage. The approach presented herein provides a new insight for self-diagnosis of defects in power equipment.

Effect of structure and phase content on wear resistance of the economical alloyed metastable and secondary hardening steels of Cr-Mn-Ti system

Despite a large number of studies in the field of assessing the causes of the formation of hot and cold cracks during surfacing of wear-resistant alloys, today the issues of working out the use of economically alloyed wear-resistant materials and the technique of their surfacing remain relevant. Goal: The purpose of this work is to study the effect of the structure and phase composition on the wear resistance of economically alloyed metastable and secondary hardening steels of the Cr-Mn-Ti system, as well as with additional alloying with Mo, B, V. Mechanized surfacing was carried out with flux cored wires AN-22 and AN-20 with the supply of a de-energized additive to the head of the weld pool, which reduces the content of sulfur and phosphorus, the specific consumption of electricity and increases the assimilation of alloying elements and the relative mass of the flux. Cladding by manual arc welding was carried out with coated electrodes with the addition of a depleted CaF2-coated flux-cored wire filler. When surfacing with a de-energized additive, the ratio of the filler to the main electrode, the relative mass was determined by β = m1 / m2 (m1, m2 are the mass of the filler and the electrode rod, respectively). Submerged arc surfacing was carried out in the following modes: IN = 300 ... 350 A, UD = 26 ... 30 V, q = 6 ... 10 kJ / cm, with manual surfacing - IN = 180 ... 220 A, UD = 25 ... Results: The studies carried out confirm the possibility of the formation of a “white band” both in alloys with a high concentration of austenitizing elements (Mn, C, Ni) and when alloying carbide-forming elements with a relatively low affinity for carbon (V, Mo). The indicators of resistance to cracking (КС, j-integral, δС), and, consequently, resistance to wear of secondary hardening steels are higher than those of metastable and tool steels.

Morphology of positive ionization waves in atmospheric pressure air: influence of electrode set-up geometry

A numerical parametric study on positive diffuse discharges in point-to-plane geometry in air at atmospheric pressure is presented. Different discharge characteristics are studied: ignition time, connection time to the grounded cathode plane, shape of the discharge and its maximum radius at the connection time, evolution of the maximum electric field in the discharge front and velocity of the ionization front during its propagation. First, a case at a DC voltage of 50 kV applied on a rod anode ended by a semi-sphere with a radius of 100 μm set at 1.6 cm from a grounded cathode plane is considered. The influence of the rod radius, the position of a disc holder, the shape of the anode electrode and the radial extension of the computational domain are studied. The radius of curvature of the anode tip (varied between 100 and 1000 μm) and the shape of the anode electrode (rod or hyperbola) are shown to have a negligible influence on discharge characteristics. Conversely, the presence of a disc holder or a small radial computational domain lead to a decrease of the maximum discharge radius at the connection time and a change in the discharge shape from a conical to an ellipsoidal shape. These changes on the discharge morphology have only a limited impact on the propagation velocity of the discharge front and maximum electric field on the discharge axis. Then, a point-to-plane geometry with a rod electrode of 50 μm radius, in a 1.6 cm gap, with a 100 kV voltage applied with a rise time of 1 ns is studied. The influence of a disc holder on the discharge characteristics is the same as for lower DC voltages. Finally, the time evolution of the absolute value of the electric field at different test points on the discharge axis is studied. Close to the anode tip, rapidly after the peak of electric field due to the passage of the ionization front, the electric field in the discharge channel is shown to increase to values higher than the breakdown field.

Study of the influence of the increased carbon content in electrodes on structure and properties of the welding seam during welding of 110G13 steel

The object of research is the effect of the carbon-forming component of coated electrodes for welding and surfacing of Gadfield steel (110G13L and analogs) on the structure and properties of the weld. One of the most problematic areas in the welding and surfacing of high-carbon steel is the high irregularity of the rod and coating melting rates. Therefore, the non-melted part of the coating is literally poured into the weld pool, which leads to significant chemical and structural inhomogeneity of the welded metal. The main hypothesis of the study is the assumption that it is possible to increase the homogeneity of the deposited metal by changing the conditions for the transition of carbon from the electrode to the weld pool by using an electrode rod made of carbon steel. In the course of the study, electrode rods with different carbon contents were used. With an increase in the carbon content in the composition of the electrode rod, the fluidity of the drops increased, which contributed to a decrease in the strength of the welding current without harm to the welding and technological characteristics. This allows to reduce the generation of heat in the base metal, that is an effective measure to prevent hot cracks in the weld metal and heat affected zone Studies of the composition of the electrode metal droplets and the weld material showed that with an increase in the carbon content in the electrode rod from 0.08 % to 0.8 %, the carbon content in the droplets increases from 0.3 % to 0.97 %. The carbon content in the weld metal is 1.1 %. The assimilation of manganese by a drop increases with an increasing of coating and the droplet interaction time. A significant increasing in the rate of coating melting was obtained. This is due to the fact that the concomitant decrease in the content of graphite in the coating contributes to a decrease in the refractoriness of the electrode coating. The use of high carbon steels for the manufacturing of electrode rods for welding and surfacing of Gadfield steel improves the properties of the welded metal and sanitary and hygienic parameters.

Pemanfaatan Drainase (Saluran) Air Bekas Limbah Rumah Tangga sebagai Solusi untuk Penurunan Resistansi Pentanahan (Grounding)

This study aims to anticipate a high value of grounding resistance by utilizing drainage or waste water from household waste as a planting medium to reduce the value of grounding resistance. The research method used is an experimental method of testing and measuring at field locations. In this study, a round rod electrode is coated with copper, namely testing with one electrode rod and two electrode rods that are installed in parallel or better known as the use of a driven rod. The results showed a decrease in the value of the grounding resistance where the average value for 1 grounding rod was 18.32 ohms and 11.82 ohms for the measurement of 2 grounding rods installed in parallel. From the test results, there was a decrease in the resistance value of 59.52% for 1 electrode rod and a 51.75% decrease for 2 electrode rods, where the decrease in the resistance value in the field was caused by factors of water, humidity and used water minerals from household waste. In conclusion, housing with reddish yellow podzolic soil that is clay (high soil resistance) by utilizing water drainage is a solution to reduce grounding resistance.
 Keywords: Resistance, Drainage, Grounding (Grounding)

High-Temperature Tribological Behavior of Nickel-Based Hardfacing Alloys

The friction and wear behavior of electrode rod nickel chromium (ER NiCr) nickel-based hardfacing alloys ER NiCr-A, ER NiCr-B, and ER NiCr-C deposited over austenitic stainless steel was studied against silicon carbide counter body by ball-on-disc tribotesting at 25 °C (1 bar pressure, 3 × 10−5 mbar vacuum) and at 550 °C (3 × 10−5 mbar vacuum) temperature. The wear tracks were examined using confocal microscope, profilometer and Raman Spectroscopy. The friction coefficient and wear rate of the deposits are correlated with the microstructure of the alloy. Wear rate of NiCr-B is found to be minimum both at ambient and elevated temperatures and can be considered as the best choice among the three alloys studied for hardfacing applications.

WITHDRAWN: Study for electrical breakdown within dielectric liquids due to streamer discharge in rod-to-plane electrodes configuration

In this paper, a computer simulation is done to study the impact of the radius of anode electrode on behavior of electrical discharge in liquid dielectric (nitrogen and water). Different radiuses of anode electrode (rod) were used to determine the breakdown voltage values within 2 mm gap length. This simulation is based on the bubble model for the determination of the initiation and growth of the streamer discharge. Laplace’s equation is solved numerically with the use of finite element approach which was known to be an accurate numerical technique, to determine the electric field. A numerical simulation was executed for tracking streamer discharge between both electrodes for the gap length distance. The results of the simulation have shown the streamer channels’ path and their branches from anode to cathode. DC applied voltage varies, and minimal value which has resulted in streamer for bridging the gap and touches the plane has been specified as the voltage of the breakdown. It has been discovered that the voltage of the breakdown is increased with the increase of anode electrode (rod) radiuses. The breakdown voltage is affected strongly by radiuses of electrodes (anode). Also, the effects of rod radius on the streamer propagation and branching.

Measurement of Earth Value Using Earth Tester Measurement at Efarina University

Grounding refers to the connection of an electrical equipment or installation to the ground so that it can protect humans from electric shock , and secure installation components from the danger of abnormal current voltages . This grounding system has low resistance properties, so that the overcurrent in the installation network can be flowed quickly to the ground to minimize damage to equipment in the building and protect the people inside. This study reviews the measurement of grounding around the earth at the efarina university. To find out the condition of the grounding resistance at each grounding, it is necessary to measure each grounding by measuring directly on the grounding installation network using an earth tester using an electrode pin. The calculation of grounding resistance is based on the type of soil, the depth of the electrode rod. The results show that the earth around the campus lobby has met the General Electrical Installation Requirements (PUIL) standard, which is smaller than 5 ohms. However, for earthing around the health faculty, it does not meet the PUIL standard, which is less than 5 ohms.

Proton-Conducting Polyoxometalates as Redox Electrolytes Synergistically Boosting the Performance of Self-Healing Solid-State Supercapacitors with Polyaniline

Energy storage devices with high volumetric and gravimetric capacitance are in urgent demand due to the booming market of portable and wearable electronics. Using redox-active molecules as electrol...