Optimal Electrodeposition Research Articles

The effect of electrodeposition time on CuCl anodes from waste copper etchant

As one common industrial waste liquid, waste copper (Cu) etchant can seriously pollute the environment if it is unreasonably managed. Herein, tetrahedron-like copper (I) chloride (CuCl) crystals were extracted from waste copper etchant by way of facile electrodeposition, and the effect of the electrodeposition time on the lithium (Li)-storage capacity of the copper (I) chloride crystal was further investigated. The results showed that the copper (I) chloride crystal had a regular tetrahedral morphology, and the density of the regular tetrahedral particles gradually increased with the extension of the electrodeposition time from 5 to 15, 20 and 25 s. Correspondingly, the reversible lithium-storage capacity of the copper (I) chloride anode experienced an initial increase and a subsequent decrease. In detail, when cycling at 2 C for 250 cycles, the reversible discharge capacity of the copper (I) chloride anode increased from 187·3 mAh/g at 5 s to 284·5 mAh/g at 15 s and then decreased to 191·9 mAh/g at 20 s and to 125·3 mAh/g at 25 s, indicating that 15 s may be the most optimal electrodeposition time. Excessive copper (I) chloride particles may result in poor performance due to the poor inherent conductivity of copper (I) chloride. Such efforts would alleviate environmental pollution and facilitate the circular economy of wastes.

Cochlear implantation in an animal model documents cochlear damage at the tip of the implant

IntroductionElectrocochleography has recently emerged as a diagnostic tool in cochlear implant surgery, purposing hearing preservation and optimal electrode positioning. ObjectiveIn this experimental study, extra-cochlear potentials were obtained during cochlear implant surgery in guinea pigs. The aim was to determine electrophysiological changes indicating cochlear trauma after cochleostomy and after electrode implantation in different insertion depths. MethodsNormal-hearing guinea pigs (n = 14) were implanted uni- or bilaterally with a multichannel electrode. The extra-cochlear cochlear nerve action potentials were obtained in response to acoustic stimuli at specific frequencies before and after cochleostomy, and after introduction of the electrode bundle. After the electrophysiological experiments, the guinea pigs were euthanized and microtomography was performed, in order to determine the position of the electrode and to calculate of the depth of insertion. Based on the changes of amplitude and thresholds in relation to the stimulus frequency, the electrophysiological data and the position obtained by the microtomography reconstruction were compared. ResultsCochleostomy promoted a small electrophysiological impact, while electrode insertion caused changes in the amplitude of extra-cochlear electrophysiological potentials over a wide range of frequencies, especially in the deepest insertions. There was, however, preservation of the electrical response to low frequency stimuli in most cases, indicating a limited auditory impact in the intraoperative evaluation. The mean insertion depth of the apical electrodes was 5339.56 μm (±306.45 – 6 inserted contacts) and 4447.75 μm (±290.23 – 5 inserted contacts). ConclusionsThe main electrophysiological changes observed during surgical procedures occurred during implantation of the electrode, especially the deepest insertions, whereas the cochleostomy disturbed the potentials to a lesser extent. While hearing loss was often observed apical to the cochlear implant, it was possible to preserve low frequencies after insertion.

Optimizing Electrode Positions in 2-D Electrical Impedance Tomography Using Deep Learning

Electrical Impedance Tomography (EIT) is a powerful tool for non-destructive evaluation, state estimation, and process tomography - among numerous other use cases. For these applications, and in order to reliably reconstruct images of a given process using EIT, we must obtain high-quality voltage measurements from the target of interest. As such, it is obvious that the locations of electrodes used for measuring plays a key role in this task. Yet, to date, methods for optimally placing electrodes either require knowledge on the EIT target (which is, in practice, never fully known) or are computationally difficult to implement numerically. In this paper, we circumvent these challenges and present a straightforward deep learning based approach for optimizing electrodes positions. It is found that the optimized electrode positions outperformed "standard" uniformly-distributed electrode layouts in all test cases. Further, it is found that the use of optimized electrode positions computed using the approach derived herein can reduce errors in EIT reconstructions as well as improve the distinguishability of EIT measurements.

Improvement of lean blow out performance of spray and premixed swirled flames using nanosecond repetitively pulsed discharges

Plasma-Assisted Combustion (PAC) has shown potential in improving the ignition, extinction, and dynamic performance of combustion systems. In this work, nanosecond repetitively pulsed (NRP) spark discharges are applied to extend the lean blow out (LBO) limit of the SICCA-Spray burner. This laboratory-scale atmospheric test rig is equipped with a swirl spray injector representing in an idealized fashion a single sector of a gas turbine. Three fuels and injection conditions are considered: perfectly premixed methane–air, liquid heptane, and liquid dodecane injected as hollow cone sprays. The optimal electrode position that extends the LBO limit is found to be near the external edge of the outer recirculation zone (ORZ). Spectroscopic measurements show that the NRP sparks produce atomic species and heat the gas above the adiabatic flame temperature. High-speed chemiluminescence images of blow out sequences indicate that the flame evolves similarly for all three fuels from “M” or “V” shapes prevailing at ϕ=0.9 to a configuration where chemical conversion also takes place in the ORZ at ϕ=0.63. A low frequency combustion oscillation arises near the LBO limit (ϕ=0.57). Spray flames blow out at this point, while the plasma-assisted ones continue to burn. It is shown that PAC provides a significant improvement of the extinction performance, in particular when operating with liquid fuel spray injection.

A silver/silver chloride woven electrode with convex based on electrical impedance tomography

Advanced wearable medical devices are widely used for health monitoring, i.e. recording and analyzing signals from human organs. However, the signal quality is influenced significantly by medical electrodes, which became the bottleneck for health monitoring due to unstable impedance under long-term daily usage. Here, a novel monitoring electrode was designed with uniform micro-convex shape to increase the impedance reliability of electrode-skin interface in long-term monitoring and under dynamic conditions, and we set up the electrode-skin interface model to describe the electrode-skin interface and impedance distribution clearly. Furthermore, we investigated how the electrodeposition factors affect the electrode deposition uniformity and electrode resistance. In this study, we compared the monitoring performance among two sets of electrodes: 1) Ag electrodes and Ag/AgCl electrodes, 2) plain Ag/AgCl electrodes, jacquard Ag/AgCl electrodes, and commercial wet electrodes. Specifically, the monitoring performance was quantified by the electrode-skin interface impedance during long-term monitoring, under different dynamic conditions. The optimal electrodeposition process was a ‘small step’ multi-potential method with the 1-1.5-2 V mode. The jacquard Ag/AgCl electrodes presented the best monitoring performance under all three measurement scenarios across four types of electrodes. The results indicated that the proposed electrodes could be used for long-term medical monitoring under daily life activities based on electrical impedance tomography.

High-capacity charge storage electrodes based on nickel oxide and nickel–cobalt double hydroxide nanocomposites on 3D nickel foam prepared by sparking and electrodeposition

Abstract In the present work, nickel oxide (NiO) and nickel-cobalt double hydroxide (NiCo-DH) nanocomposites on Ni foams were synthesized for the first time and systemically optimized for charge storage applications. NiO nanoparticles were sparked on Ni foams followed by the electrodeposition of NiCo-DH with various times ranging from 50 to 400 s. Structural characterization results by electron microscopy, Raman spectroscopy and X-ray spectroscopy revealed that 5–10 nm sparked NiO nanoparticles acted as the nucleation seeds for the formation of smaller NiCo-DH nanostructures resulting in an increase of surface area at a moderate electrodeposition times of 100 s and induced metallic Ni and Co species on the composite layer. From electrochemical measurements, the optimal electrodeposition time of 100 s provided a moderate mass loading of 0.6 mg cm−2 and a high specific capacity of 938 C g−1 (1876 F g−1) @ 1 A g−1 with a good rate capability of 69% (647.5 C g−1) @ 20 A g−1. Additionally, a decent capacity retention of 97% was attained after 1000 cycles @ 4 A g−1. The results could be attributed to high surface capacity of NiO + NiCo-DH nanocomposite structures and high electrical conductivity with a low effective series resistance of 0.39 Ω.

A stearic Acid/CeO2 bilayer coating on AZ31B magnesium alloy with superhydrophobic and self-cleaning properties for corrosion inhibition

Abstract Corrosion is one of the most challenging issues for the large-scale application of magnesium alloys. Fabricating a superhydrophobic surface with a low-cost, easy-to-handle method is meaningful for anti-corrosion protection of Mg alloys. In this study, a stearic acid/CeO2 bilayer coating was prepared on AZ31B Mg by a simple electrodeposition method combined with immersion in stearic acid solution. The growth traits of the coating with different electrodeposition current densities and time were evaluated, which demonstrated that 60 min combined with 0.65 mA/cm2 is the optimal electrodeposition condition. Besides, the wettability, anti-corrosion ability, durability, chemical stability and self-cleaning properties of the coating were comprehensively investigated. The results showed that the as-prepared coating exhibited a good superhydrophobic and self-cleaning property with CA>158° and SA

Recovery of Ni(II) from real electroplating wastewater using fixed-bed resin adsorption and subsequent electrodeposition

Effective recovery of high-value heavy metals from electroplating wastewater is of great significance, but recovering nickel ions from real electroplating wastewater as nickel sheet has not been reported. In this study, the pilot-scale fixed-bed resin adsorption was conducted to recover Ni(II) ions from real nickel plating wastewater, and then the concentrated Ni(II) ions in the regenerated solution were reduced to nickel sheet via electrodeposition. A commercial cation-exchange resin was selected and the optimal resin adsorption and regeneration conditions were investigated. The resin exhibited an adsorption capacity of 63 mg/g for Ni(II) ions, and the average amount of treated water was 84.6 bed volumes (BV) in the pilot-scale experiments. After the adsorption by two ion-exchange resin columns in series and one chelating resin column, the concentrations of Ni(II) in the treated wastewater were below 0.1 mg/L. After the regeneration of the spent resin using 3 BVof 4% (w/w) HCl solution, 1.5 BV of concentrated neutral nickel solution (>30 g/L) was obtained and used in the subsequent electrodeposition process. Using the aeration method, alkali and water required in resin activation process were greatly reduced to 2 BV and 3 BV, respectively. Under the optimal electrodeposition conditions, 95.6% of Ni(II) in desorption eluent could be recovered as the elemental nickel on the cathode. The total treatment cost for the resin adsorption and regeneration as well as the electrodeposition was calculated.

Hydrodynamics Analysis for an Upflow Integrated Anaerobic Digestion Reactor with Microbial Electrolysis under Different Hydraulic Retention Times: Effect of Bioelectrode Spatial Distribution on Functional Communities Involved in Methane Production and Organic Removal

The electrode plays a significant role in an integrated anaerobic digestion reactor with microbial electrolysis that can increase energy production. Optimizing electrode positions by means of hydro...

Influence of electrodeposition potential, TiO2 nanoparticles and chromium (III) inhibitor addition on the corrosion protection performance of organosilane coating on aluminium

ABSTRACTIn this work, the anticorrosion properties of phenyl trimethoxysilane (PTMS) films coated on aluminium 5000 series alloys were studied. PTMS films were deposited at various cathodic potentials. The optimum electrodeposition potential was found to be −0.8 V vs. SCE. The coatings were also modified by different amounts of nano-TiO2. In order to introduce corrosion inhibition and a self-repair property of the PTMS film, the addition of chromium (III) corrosion inhibitor in the presence of nano-TiO2 was studied. The anticorrosion performance of coatings was investigated in a 3.5 wt.% NaCl solution. At optimum deposition potential, the ‘critical’ nano-TiO2 and Cr(III) contents were both observed, under which the obtained PTMS coatings show the highest anticorrosion performance. The surface morphologies of PTMS coatings were examined by scanning electron microscopy. The results showed that the coatings deposited at −0.8 V vs. SCE, from 20 ppm of nano-TiO2 and 0.003 M Cr(III) inhibitor present uniform and compact morphologies.

Synthesis and characterization of a novel non-enzymatic glucose biosensor based on polyaniline/zinc oxide/multi-walled carbon nanotube ternary nanocomposite

Novel polyaniline/zinc oxide/multi-walled carbon nanotube (PANI/ZnO/MWCNT) ternary nanocomposite was fabricated as a non-enzymatic glucose biosensor. Thermal chemical vapor deposition (CVD) process was employed to synthesize vertically aligned MWCNTs on stainless steel substrates coated by Co catalyst nanoparticles. In order to fabricate sensitive and reliable MWCNT-based biosensors, nanotubes density and alignment were adjusted by varying the CVD reaction time and cobalt sulfate concentration. The fabricated nanotubes were modified by ZnO particles through the potentiostatic electrodeposition technique. Optimal electrodeposition potential, electrodeposition time, and electrolyte concentration values were determined. The optimized ZnO/MWCNT nanocomposite was reinforced by polyaniline (PANI) nanofibers through the potential cycling technique, and the morphology, elemental composition, and phase structure of the fabricated nanocomposites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD), respectively. The sensing mechanism of the PANI/ZnO/MWCNT electrode for the electrochemical detection of glucose was investigated, and the limit of detection and sensitivity values of the designed sensor were determined. The fast response time of the ternary nanocomposite-based sensor as well as its satisfactory stability and reproducibility, makes it a promising candidate for non-enzymatic detection of glucose in biomedical, environmental, and industrial applications.

Morphological and mechanical characterization of co-deposited Ni/Cr3C2–NiCr composite coatings

In this study, the coating of Ni/Cr3C2–NiCr composite by electrodeposition technique on copper alloy was investigated. Different coatings were formed with and without carbide particles to study the effect of carbide particles on the mechanical properties of coatings. The deposited layers were characterized by using scanning electron microscopy (SEM) to study the morphology of formed coatings, energy dispersive x-ray spectrometry (EDS) to study the chemical composition of coatings and x-ray diffraction (XRD) to examine phase and crystallinity of coatings. Microhardness and wear resistance tests were performed to evaluate mechanical properties of coatings. Optimum electrodeposition conditions were obtained when maximum amount of chromium carbide was used, achieving maximum hardness of 650 Hv, which was absolutely higher than that of the pure nickel deposited specimen. Results of wear test showed that the friction coefficient of Ni/Cr3C2–NiCr coating was as low as 0.41. Low friction coefficient, high hardness and resistance to wear of these coating are promising for applications that need such excellent properties.

Transcranial bioimpedance measurement in horses: a pilot study

ObjectiveThis pilot study aimed to evaluate the feasibility of transcranial bioimpedance (TCBI) measurement and variability of TCBI values in healthy conscious horses and to study effects of body position and time on TCBI in anaesthetized horses. Study designProspective, observational study. AnimalsA total of four research horses and 16 client-owned horses presented for surgery. MethodsAfter establishing optimal electrode position using computed tomography scans of cadaver heads, TCBI [described using impedance at zero frequency, R0, (Ω)] was measured in four conscious, resting horses to investigate the feasibility and changes in TCBI over time (80 minutes). Data were compared using a paired t test. TCBI was then measured throughout anaesthesia (duration 92 ± 28 minutes) in 16 horses in dorsal and lateral recumbency. Data were analysed using a general linear model; gamma regression was chosen as a model of characteristic impedance [Zc; (Ω)] against time. Data are presented as mean ± standard deviation. ResultsNo change in R0 was seen in conscious horses (age = 15.3 ± 7.3 years, body mass = 512 ± 38 kg) over 80 minutes. The technique was well tolerated and caused no apparent adverse effects. In 16 horses (age = 7.4 ± 4.7 years; body mass = 479 ± 134 kg) anaesthetized for 92 ± 28 minutes, Zc fell during anaesthesia, decreasing more in horses in lateral recumbency than in horses in dorsal recumbency (p = 0.008). There was no relationship between Zc and body mass or age. Conclusions and clinical relevanceTCBI is readily measured in horses. TCBI did not change with time in conscious horses, but decreased with time in anaesthetized horses; this change was greater in horses in lateral recumbency, indicating that TCBI changes in anaesthetized horses may be related to the effects of recumbency, general anaesthesia, surgery or a combination of these factors.

Analysis of Miniaturization Effects and Channel Selection Strategies for EEG Sensor Networks With Application to Auditory Attention Detection.

Concealable, miniaturized electroencephalography (mini-EEG) recording devices are crucial enablers toward long-term ambulatory EEG monitoring. However, the resulting miniaturization limits the inter-electrode distance and the scalp area that can be covered by a single device. The concept of wireless EEG sensor networks (WESNs) attempts to overcome this limitation by placing a multitude of these mini-EEG devices at various scalp locations. We investigate whether optimizing the WESN topology can compensate for miniaturization effects in an auditory attention detection (AAD) paradigm. Starting from standard full-cap high-density EEG data, we emulate several candidate mini-EEG sensor nodes that locally collect EEG data with embedded electrodes separated by short distances. We propose a greedy group-utility based channel selection strategy to select a subset of these candidate nodes to form a WESN. We compare the AAD performance of this WESN with the performance obtained using long-distance EEG recordings. The AAD performance using short-distance EEG measurements is comparable to using an equal number of long-distance EEG measurements if, in both cases, the optimal electrode positions are selected. A significant increase in performance was found when using nodes with three electrodes over nodes with two electrodes. When the nodes are optimally placed, WESNs do not significantly suffer from EEG miniaturization effects in the case of AAD. WESN-like platforms allow us to achieve similar AAD performance as with long-distance EEG recordings while adhering to the stringent miniaturization constraints for ambulatory EEG. Their applicability in an AAD task is important for the design of neuro-steered auditory prostheses.

PENGEMBANGAN METODE ELEKTRODEPOSISI UNTUK PENGAMBILAN KEMBALI PERAK DARI LIMBAH FOTORONTGEN

Silver in its ionic form is one of the heavy metals dangerous if it is discharged into the environment or into the body of humans or other living things. Silver metal pollution sources, one of which comes from waste fixer which is a waste from the photorontgen process. However, silver in its metal form has a high economic value. Therefore, the development of techniques or methods of recovering silver from the waste solution and turning it into a metal form is important to do so that the metal does not pollute the environment and can be reused economically. One method that can be done is by electrolytic deposition or electrodeposition in which silver in the form of a silver thiosulfate complex compound in the photorontgen waste is converted to Ag metal through a redox reaction. To obtain good quality and quantity of silver deposits in the electrodeposition process, it is necessary to optimize several factors that influence, among others, optimization of potential difference, time and pH of the solution. This study aims to determine the effect of potential difference, time and pH of the solution on the efficiency of the electrodeposition process. Electrodeposition efficiency was determined based on the percentage of reduced silver mass calculated from the decrease in Ag concentration in photorontgen waste solution before and after the electrodeposition process. Based on the results of the study obtained the optimum electrodeposition process at a potential difference of 8 V for 75 minutes and the pH of the waste is 3, where the mass percent of silver which is reduced from waste is 86.49%.

Mechanical and biological properties of electrodeposited calcium phosphate coatings

Calcium phosphate (CaP) coatings were electrochemically deposited on titanium substrates. By increasing the electrodeposition time (from 1 to 30 min), the coating thickness increases but also the surface morphology of the CaP coatings is greatly affected going from smooth to plate-like, featuring elongated plates, ribbon-like and finally sharp needle structures. Micro-stretch tests reveal that, regardless of the coating morphology and thickness, the electrodeposited CaP coatings have strong adhesion with the titanium substrates and their failure mode is cohesive failure. The effects of different morphologies on cellular behavior such as adhesion, viability, proliferation, and osteogenic gene expression were studied. The surface morphology of CaP coatings has a remarkable effect on cell attachment, proliferation, and viability. A smooth surface results in better adhesion of the cells, whereas the presence of sharp needles and ribbons on rough surfaces restricts cell adhesion and consequently cell proliferation and viability. The improved cell adhesion and viability on the smoother surface can be attributed to the higher contact area between the cell and the coating, while the needle-like morphology inflicts damage to the cells by physically disrupting the cell wall. There is no significant difference in the level of osteoblast gene expression when osteosarcoma cells are cultured on coatings with different morphologies. Our study provides crucial insights into the optimum electrodeposition procedures for CaP coating formation leading to both good cell-material interaction and sufficient mechanical properties. This can be achieved with relatively thin coatings produced by short electrodeposition times.

Impact of Routine Plain X-ray on Postoperative Management in Cochlear Implantation.

To determine the benefit of a routine plain radiography (X-ray) for confirming the optimal electrode position in cochlear implant surgery. In total, 245 patients (135 males and 111 females) who underwent cochlear implantation in a single tertiary referral center were included in this study. Postoperative plain X-ray findings and electrophysiological tests were retrospectively analyzed. The mean age was 11.4±14.6 years (range, 1-70 years). Overall, 196 (80%) patients were pediatric patients (age, <18 years) and 49 (20%) were adults (age, >18 years). The mean rotation of electrode arrays was 1.03±0.17 turns. The plain X-ray revealed that electrode misplacement was present in 5 patients (2%); incomplete insertion in 3 patients, and tip rollover and electrode migration in 1 patient each. A revision was performed for the last patient who had an extracochlear electrode position in the plain X-ray. Postoperative imaging is mostly used to confirm the electrode array position after cochlear implant surgery. In addition, intraoperative evaluations have low positive predictive value and sensitivity. Thus, this study revealed that postoperative radiological imaging should be considered even when all intraoperative electrophysiological measures and surgical reports are normal.

Optimization of the Position of Single-Lead Wireless Sensor with Low Electrodes Separation Distance for ECG-Derived Respiration

A classical method for estimation of respiratory information from electrocardiogram (ECG), called ECG - derived respiration (EDR), is using flexible electrodes located at standard electrocardiography positions. This work introduces an alternative approach suitable for miniaturized sensors with low inter-electrode separation and electrodes fixed to the sensor encapsulation. Application of amplitude EDR algorithm on single-lead wireless sensor system with optimized electrode positions shows results comparable with standard robust systems. The modified method can be applied in daily physiological monitoring, in sleep studies or implemented in smart clothes when standard respiration techniques are not suitable.

Electrodeposition of Co-Ni-Fe on Stainless Steel Bolts

In a fastening system, bolt is the first component to be susceptible to corrosive attack. The focus of the study is to investigate the feasibility of coating stainless steel 304 bolts and the coating properties obtained. In this study, the bolts were coated with cobalt-nickel-iron (Co-Ni-Fe) alloy through electrodeposition using platinized titanium as the anodes. The temperature used was 50°C and the pH of the sulphate solution were 2. The current density was 96.68 mA/cm2 and deposition time was 30 minutes. The optimum electrodeposition parameters were studied through trial and error. The characteristics of coating such as elemental percentage and microhardness were compared with the substrate. The optimum parameters obtained were current density of 145.01 mA/cm2, temperature of 60°C and 30 minutes of deposition time. The suitable substrate orientation was horizontally hanged and rotated 60° around screw axis for every 5 minutes. The mean thickness of coating was 117.4 µm. The coating exhibited 25% hardness improvement over the substrate. The 2 litres solution could be used for 7.5 hours (15 plating cycles) to produce 15 samples. As a conclusion the surface hardness was not compromised despite that Co-Ni-Fe ions had depleted in the solution.

Single-step pulsed electrodeposition of calcium phosphate coatings on titanium for drug delivery

Metallic implants have some limitations related to bioactivity and bacteria colonization leading to infections. In this regard, calcium phosphate coatings can be used as carrier for drug delivery in order to improve the mentioned drawbacks. The present work proposes the introduction of an antibacterial agent in the course of a pulsed and reverse pulsed electrodeposition. Calcium phosphate coatings were prepared in 30 min using different pulse waveforms (unipolar-bipolar), current densities (2–5 mA/cm2) and temperatures (40–60 °C). Mechanical stability of the as-coated surfaces was studied in order to select the optimal electrodeposition conditions. Subsequently, selected coatings were loaded with an antiseptic agent, chlorhexidine digluconate (CHX), via a single-step co-deposition procedure. CHX concentration added to the electrolyte was adjusted to 3 mM based on the antibacterial efficacy of the loaded coatings evaluated in vitro with Staphylococcus aureus and Escherichia coli bacteria strains. Whereas the same chlorhexidine concentration was added to the electrolyte, results showed that the amount of CHX loaded was different for each condition while release kinetics was maintained. The results of this work demonstrate that a pulsed co-deposition strategy has great potential to modulate local delivery of antibacterial agents such as chlorhexidine digluconate, which may prevent early phase infections of metallic implants after insertion.