Application Of Electric Current Research Articles

Enhanced copper removal from contaminated kaolinite soil by electrokinetic process using compost reactive filter media

Electrokinetic (EK) remediation is a promising technology for soil decontamination, although basic pH in the soil close to cathode has constrained EK effectiveness due to heavy metal precipitation. This study aimed to enhance copper removal from kaolinite soil by integrating EK with compost (C) as recyclable reactive filter media (RFM) for the first time. Compost placed near the cathode served as an adsorbent to bind copper ions while buffering the advancement of the alkaline front in soil. The total copper removal rate increased from 1.03% in EK to 45.65% in EK-100%C under an electric potential of 10 V. Further experiments conducted by using biochar (BC) and compost/biochar (C + BC) mixture RFM at different ratios showed total Cu removal efficiency decreasing as EK-100%C > EK-(10%BC + 90%C) > EK-(20%BC + 80%C) > EK-(30%BC + 70%C) > EK. The application of a constant electric current of 20.00 mA further enhanced copper removal to 84.09% in EK-100%C although did not show significant enhancement in EK-(BC + C). The compost RFM was regenerated by acid extraction and then reused twice, achieving a total removal of 74.11%. The findings demonstrated compost as a promising and reusable RFM for the efficient removal of copper in contaminated soil.

Joule Heating of Metallic Nanowire Random Network for Transparent Heater Applications

Silver nanowire random networks are promising candidates for replacing indium tin oxide (ITO) as transparent and conductive electrodes. They can also be used as transparent heating films with self-cleaning and defogging properties. By virtue of the Joule heating effect, silver nanowire random networks can be heated when voltage bias is applied; however, they are unsuitable for long-term use. In this work, we study the Joule heating of silver nanowire random networks embedded in polymers. Silver nanowire random networks embedded in polymers exhibit breakdown under the application of electric current. Their surface morphological changes indicate that nanoparticle formation may be the main cause of this electrical breakdown. Numerical analyses are used to investigate the temperatures of the silver nanowire and substrate.

Enhancing the bone healing on electrical stimuli through the dental implant

Purpose The aim of this study was to evaluate the influence of different density and amplitude of electric current on the percentage of bone-implant contact (BIC) using the finite element method. Materials and Methods Numerical models were performed on commercially pure titanium grade IV implants connected to a 1.5 V battery with an electrical resistance (R) at 150 kΩ on 10 µA or at 75 kΩ on 20 µA. The percentage of simulated BIC was analysed by varying the electric current from 1 up to 60 µA. The variation of electric current application was simulated for coronal and apical peri-implant regions. Results The findings showed that a direct and constant electric current source below 10 μA does not provide a proper current density for osseointegration (BIC < 55%). Electric current sources ranging from 10 to 20 μA resulted in an increase in BIC above 60% while BIC reached 90% on 30 to 40 μA. Also, the application of the current source on 20 μA at the apical peri-implant region resulted in a high BIC percentage at around 86.1%. Conclusions The location and intensity of the electrical current source can increase the resultant electrical current density at the implant-bone interface and enhance the bone healing process. Although the model is a simplified version of the biological process in the bone-implant interface, such findings can predict a magnitude of electrical current density required to stimulate osseointegration.

Nail drug delivery system a review

The nail is horny structure. Nail plate is responsible for penetration of drug across it. As it is hard enough the penetration becomes difficult, only a fraction of topical drug penetrates across it. Hence the effective therapeutic concentration is not achieved. The nail plate may appear abnormal as a result of decreased glow. It`s involvement of nail bed, reduction of blood supply, physical or chemical features of nail bed. As a result variety of diseases occurs.1 Oral therapies are accompanied by systemic side effects and drug interactions, while topical therapies are limited by the low permeation rate through the nail plate. These diseases can be cured by achieving desired therapeutic concentration of drug by nail drug delivery system. Human nails do not have only protective and decorative role, but can also be considered as an alternative pathway for drug delivery, especially in nail diseases such as onychomycosis or psoriasis. The physical techniques (manual and electrical nail abrasion, acid etching, ablation by lasers, microporation, application of low-frequency ultrasound and electric currents) and chemicals (thiols, sulphites, hydrogen peroxide, urea, water, enzymes) that have shown ungual enhance reactivity. For effective topical therapy, fungal drug permeation must be enhanced.3 This can be achieved by disrupting the nail plate using physical techniques or chemical agents. Alternatively, drug permeation into the intact nail plate may be encouraged, for example, by iontophoresis or by formulating the drug within a vehicle which enables high drug partition out of the vehicle and into the nail plate. Keywords: Nail drug delivery, Onychomycosis, Iontophoresis, Psoriasis.

Membrane fouling suppression using intermittent electric current with low exposure time in a sequencing batch membrane bioreactor

Abstract This study assessed for the first time the use of intermittent electric current with low exposure time in a sequential batch membrane bioreactor (SB-MBR) aiming at reducing the membrane fouling and improving the treatment performance. The SB-MBR was initially operated without electric current application (control period) and, subsequently, using the electric current density of 10 A m−2 and intermittent exposure mode of 6 min ON/30 min OFF (1.2 h d−1). Compared to the control period, the mixed liquor filterability improved substantially when the electrocoagulation was applied, resulting in a membrane fouling rate 65% lower. This better filterability condition was attributed to the improvement of the floc formation process, which resulted in larger floc size and lower sludge volume index. The biomass growth was positively impacted by the electrochemical process, resulting in a higher sludge yield coefficient. The reactor performance regarding COD and NH4+-N removal was not influenced by the electric current application, exhibiting efficiencies above 99% in both experimental periods. On the other hand, the phosphorus concentration in the reactor effluent decreased as the electrocoagulation was applied, increasing its average removal efficiency from 62% (control period) to 89%. The anodic dissolution rate was estimated at 1.28 g d−1, considerably lower than the values reported in other studies regarding EBRM running in continuous mode. Thus, it can be inferred that the integration of the electrochemical process with SB-MBR using low exposure mode is an interesting alterative to reduce the membrane fouling, extend the anode lifespan and improve the reactor performance.

Effect of power supply type on the electroplastic effect

Abstract The electroplastic effect (EPE) encompasses the known reduction in flow stress and increase in ductility in a metal resulting from the application of an electric current concurrently with deformation, a phenomenon which cannot be accounted due solely to resistive heating. While several theories have been postulated, the mechanism responsible for the electroplastic effect is still in debate after nearly 60 years of scientific research. A significant amount of research has been conducted on the anomalous effects observed when performing research on the EPE. Particular behaviors which remain elusive are the transient effect of electric current application and the difference between constant and pulsed current applications. Throughout literature, the type of power supply used in electric current application appears to be ignorantly selected and output signals improperly or incompletely documented. It was found herein that the type of power supply used in electrically assisted tensile testing can have a significant effect on the resulting transient mechanical behavior for pulsed current testing within the parameters explored in this research.

Critical Review of Transcutaneous Vagus Nerve Stimulation: Challenges for Translation to Clinical Practice.

Several studies have illustrated that transcutaneous vagus nerve stimulation (tVNS) can elicit therapeutic effects that are similar to those produced by its invasive counterpart, vagus nerve stimulation (VNS). VNS is an FDA-approved therapy for the treatment of both depression and epilepsy, but it is limited to the management of more severe, intervention-resistant cases as a second or third-line treatment option due to perioperative risks involved with device implantation. In contrast, tVNS is a non-invasive technique that involves the application of electrical currents through surface electrodes at select locations, most commonly targeting the auricular branch of the vagus nerve (ABVN) and the cervical branch of the vagus nerve in the neck. Although it has been shown that tVNS elicits hypo- and hyperactivation in various regions of the brain associated with anxiety and mood regulation, the mechanism of action and influence of stimulation parameters on clinical outcomes remains predominantly hypothetical. Suppositions are largely based on correlations between the neurobiology of the vagus nerve and its effects on neural activity. However, tVNS has also been investigated for several other disorders, including tinnitus, migraine and pain, by targeting the vagus nerve at sites in both the ear and the neck. As most of the described methods differ in the parameters and protocols applied, there is currently no firm evidence on the optimal location for tVNS or the stimulation parameters that provide the greatest therapeutic effects for a specific condition. This review presents the current status of tVNS with a focus on stimulation parameters, stimulation sites, and available devices. For tVNS to reach its full potential as a non-invasive and clinically relevant therapy, it is imperative that systematic studies be undertaken to reveal the mechanism of action and optimal stimulation modalities.

Electroplasticity effects in Haynes 230

Electrically-assisted forming has the potential to reduce the cost of hot working Haynes 230 by enabling better material utilization, shorter cycle times and lower energy costs. In this paper, we investigate the presence of an electroplastic effect in Haynes 230 through electrically-assisted and isothermal tensile testing, thermomechanical simulation and microstructural characterization. Experimental results show discernable reductions in yield strength and elongation between a purely thermal response and an electrically-activated thermal response across the space of parameters studied. Evidence of a “rapid aging” effect during the electrically-assisted pulling of Haynes 230 is demonstrated via microstructural characterization. Results suggest that in Haynes 230, localized joule heating is brought on by electron-ion collisions which leads to fast precipitation of solutionized elements that increase subsequent flow stresses compared to an equivalent purely-thermal response without the application of electric current.

Effect of Electric Current-assisted Application of Adhesives on their Bond Strength and Quality.

To assess the effect of the application of different electric currents on dentin bonding and resin infiltration of self-etching and etch-and-rinse adhesives. Two hundred four sound third molars were selected and divided in groups according to the adhesive (self-etch [CSE, Clearfil SE Bond, Kuraray Noritake], universal [SBU, Single Bond Universal, 3M Oral Care], and etch-and-rinse [SB2, Adper Single Bond 2 (SB2), 3M Oral Care]) and electrical current used (0, 5, 10, 15, 20, 25, 30, and 35 μA). Light curing was performed for 10 s with an LED-curing unit at 1000 mW/cm2. Composite blocks were constructed of nanofilled composite in increments of 2 mm, which were light cured for 20 s. Specimens were sectioned into sticks with a cross-sectional area of ~1 mm2 and stored in distilled water at 37°C for 24 h. Microtensile bond strength (μTBS) testing (n = 8) was performed using a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The bonding quality (n = 2) of adhesives applied with or without 35-μA electric current was evaluated using confocal laser scanning microscopy. Bond strengths were analyzed with two-way ANOVA and Tukey's test (α = 0.05). CSE presented the highest μTBS for all electrical currents tested. For CSE and SBU, electrical currents from 0-20 μA showed the lowest μTBS. Electrical currents from 0-10 and 20-25 μA yielded the lowest μTBS for SB2. CSE and SB2 applied under 35 μA showed a greater number of resin tags in dentin tubules. Fluorescein penetration into the hybrid layer was found for SBU applied without electric current. The application of adhesives using 35-μA electric current improved the bond strength and quality of the adhesive interface.

Benefits and drawbacks of applied direct currents for soil improvement via carbonate mineralization

The study presented herein adopts a new vision of the processes involved in carbonate mineralization induced by MICP from an electrochemical and crystal growth perspective. More precisely a specific line of focus refers to the species involved in the bio-chemical reactions and especially their net particle charge. By altering electro-chemical conditions via the application of direct electric currents, we observe distinctive trends related to: (i) overall reaction efficiency; (ii) carbonate mineralization/dissolution and (iii) spatial distribution of precipitates. The study introduces the concept of EA-MICP which stands for Electrically Assisted MICP as a means of improving the efficiency of soil bio-consolidation and overcoming various challenges which were previously reported in conventional MICP-based works. Results reveal both the detrimental and highly beneficial role that electric currents can hold in the complex, reactive and transport processes involved. An interesting finding is the “doped” morphology of calcite crystals, precipitated under electric fields, validated by microstructural observations.

Simultaneously enhanced Cu bioleaching from E-wastes and recovered Cu ions by direct current electric field in a bioelectrical reactor

In this study, a proof-of-concept of bioleaching and recovery of copper (Cu) from E-wastes assisted by direct current (DC) electric field was proved in a bioelectrical reactor. Results showed that 40 mA electric current application could not only significantly shorten the leaching time of Cu from 5 (control) to 3 days with 100% leaching efficiency, but also recover about 97% leached Cu ions within 4 days. DC electric field improved the activity and growth of iron oxidizing bacteria and facilitated Fe2+ oxidation, which resulted in effective leaching of Cu from printed circuit boards (PCBs). The functional Acidithiobacillus was selectively enriched by DC electric field for enhancing the efficiency of bioleaching. At the same time, the leached Cu ions were rapidly electrodeposited on the cathode, achieving the recovery of Cu. Hence, this work provided a novel strategy for metals bioleaching and recovery from E-wastes.

The diffusive injection micropipette (DIMP)

The microinjection of fluorescent probes into live cells is an essential component in the toolbox of modern cell biology. Microinjection techniques include the penetration of the plasma membrane and, if present, the cell wall with micropipettes, and the application of pressure or electrical currents to drive the micropipette contents into the cell. These procedures interfere with cellular functions and therefore may induce artifacts. We designed the diffusive injection micropipette (DIMP) that avoids most of the possible artifacts due to the drastically reduced volume of its fluid contents and the utilization of diffusion for cargo delivery into the target cell. DIMPs were successfully tested in plant, fungal, and animal cells. Using the continuity of cytoplasmic dynamics over ten minutes after impalement of Nicotiana trichome cells as a criterion for non-invasiveness, we found DIMPs significantly less disruptive than conventional pressure microinjection. The design of DIMPs abolishes major sources of artifacts that cannot be avoided by other microinjection techniques. Moreover, DIMPs are inexpensive, easy to produce, and can be applied without specific equipment other than a micromanipulator. With these features, DIMPs may become the tool of choice for studies that require the least invasive delivery possible of materials into live cells.

Simulation of the Electrical Resistance Sintering of Hardmetal Powders

The simulation of the electrical resistance sintering (ERS) of hardmetal powders has been studied. The ERS process can produce a quick consolidation of electrical conductive powders by the simultaneous application of pressure and electrical current. A model of the process has been developed, integrating three actions, namely, thermal, mechanical and electrical, and taking into account the nature of both the powders and the die where powders are placed. The model has been implemented in COMSOL Multiphysics, a finite element commercial program. This paper deals with the model fundamentals and hardmetal particular aspects, such as modelling properties of mixed powders and its thermal behaviour. Other parameters in the model have been tuned to optimally fit the initial experimental data. To check simulation results, measurable parameters have been monitored during experimental tests with WC–6 wt% Co. Once the model was completed and put to work, results are discussed.

Sound- and current-driven laminar profiles and their application method mimicking acoustic responses in the mouse auditory cortex in vivo

The local application of electrical currents to the cortex is one of the most commonly used techniques to activate neurons, and this intracortical stimulation (ICS) could potentially lead to new types of neuroprosthetic devices that can be directly applied to the cortex. To identify whether ICS-activated circuits are physiological vs. profoundly artificial, it is necessary to record in vivo the responses of the same neuronal population to both natural sensory stimuli and artificial electric stimuli. However, few studies have extensively reported simultaneous electrophysiological recordings combined with ICS. Here, we evaluated the similarity between sound- and ICS-driven cortical response patterns in different cortical layers. In the mouse auditory cortex, we performed laminar recordings using 16-channel silicon electrodes and ICS using sharp glass-pipette electrodes containing biocytin for layer identification. In different cortical depths, short current pulses were delivered in vivo to mice under urethane anesthesia. For the recorded data, we mainly analyzed properties of local field potentials and current source densities (CSDs). We demonstrated that electrical stimulation evoked different excitation patterns according to the stimulated cortical layer; responses to electric stimuli in layer 4 were most likely to mimic acoustic responses. Next, we proposed a CSD-based stimulation method to artificially synthesize sound-driven responses, using an approximation method associated with a linear combination of CSD patterns electrically stimulated in the different cortical layers. The result indicates that synthesized responses were consistent with the canonical model of sound processing. Using these approaches, we provide a new technique in which natural sound-driven responses can be mimicked by well-designed computational stimulation pattern sequences in a layer-dependent manner. These findings may aid in the future development of an electrical stimulation methodology for a cortical prosthesis.

Enhancing the removal of atrazine from soils by electrokinetic-assisted phytoremediation using ryegrass (Lolium perenne L.)

Atrazine (ATR) continues being one of the most frequently detected pesticides in natural waters and soils. In this work, an electrokinetic-assisted phytoremediation pot test (EKPR) was performed for the remediation of an atrazine-spiked soil; a low electric voltage gradient (1 V cm−1) with two different electric field operation times (6 and 24 h per day) was used in combination with ryegrass (Lolium perenne L.). EKPR increased up to 27% and 7% the overall ATR removal from soil as compared to natural attenuation and phytoremediation treatments, respectively. ATR soil concentration vs time curves were fitted to a pseudofirst-order kinetic equation, obtaining ATR half-life values of 8.2, 7.1 and 5.4 days for the treatments corresponding, respectively, to 0, 6 and 24 h day−1 of electric current application. It clearly showed that the ATR removal from soils was enhanced by the electric field. ATR plant accumulation was significantly improved with respect to phytoremediation when the electric current was continuously applied throughout the experiment (24 h day−1); most of the ATR residues were accumulated in the shoot biomass of the ryegrass plants.

Effect of CO2 on the properties of anion exchange membranes for fuel cell applications

In this study the effect of CO2, HCO3‾ and CO32‾ on the ionic conductivity and water uptake properties of anion exchange membranes (AEMs) was investigated in order to better understand the detrimental effect of ambient air feed on the performance of AEM fuel cells. Three types of AEMs were examined, including Poly(hexamethyl-p-terphenyl benzimidazolium) (HMT-PMBI), Fumatech® FAA-3, and poly(phenylene oxide) functionalized with imidazole (PPO-Im). The effect of temperature and humidity on AEM properties in their different anion forms was studied, including both steady state and dynamic measurements. In addition, the response to changes in CO2 concentration and to application of ex-situ electric current was examined. Results showed that an increase in humidity leads to an increase in water content and an increase in conductivity of the AEMs, regardless the anion type. It was found that both temperature and relative humidity improve conductivity in carbonated forms, however relative humidity has the most significant impact. The carbonation process in 400 ppm CO2 is slightly quicker in AEMs with low conductivity, lasting ca. 40 min; however it was shown that a reverse process can be achieved by applying an electric current through the AEMs. An increase by 2–10 fold in conductivity is obtained using this method, which is analogous to the changes observed during operation of the fuel cell. This work provides important data that needs to be taken into account in future work in order to ultimately mitigate the carbonation effects and improve the performance of AEM fuel cells running with ambient air.

Application of pulsed electric fields in meat and fish processing industries: An overview.

The market demand for new meat and fish products with enhanced physicochemical and nutritional properties attracted the interest of the food industry and academia to investigate innovative processing approaches such as pulsed electric fields (PEF). PEF is an emerging technology based on the application of electrical currents between two electrodes thus inducing electroporation phenomena and enabling a non-invasive modification of the tissues' structure. This review provides an overview of the current knowledge on the use of PEF processing in meat and fish to enhance the physicochemical and nutritional changes, as a preservation method, as well as for improving the extraction of high added-value compounds. PEF treatment had the ability to improve several processes such as preservation, tenderization, and aging. Besides, PEF treatment could be used as a useful strategy to increase water holding properties of fish products as well as for fish drying. Finally, PEF could be also used in both meat and fish foods for by-products valorization, due to its potential to enhance the extraction of high added-value compounds. However, more studies are warranted to completely define specific treatments that can be consistently applied in the industry. This review provides the directions for this purpose in the near future.

Pulsed Electric Current V-Bending Springback of AZ31B Magnesium Alloy Sheets

The springback of AZ31B magnesium alloy sheets subjected to pulsed electric current-assisted V-bending tests was investigated. To study the effect of pulsed electric current on the bending-dominated deformation behavior of magnesium alloy sheets, the stress–strain responses from the electric current-assisted uniaxial tension and compression tests were experimentally measured. The stress–strain curves under pulsed electric current showed an instantaneous stress drop under the application of the electric pulse. The ductility was enhanced owing to the application of electric current. The electrically assisted V-bending tests helped reduce the springback compared with conventional room-temperature V-bending tests, and the magnitude of the springback reduction increased with the increase in the electric current density. A thermo-mechanical-electrical finite element model for the electrically assisted V-bending test was developed. To consider the Joule heating effect, temperature-dependent hardening and a yield function with strength differential were implemented for simulating the AZ31B sheet. The simulations could reproduce the experimental flow stress curves of the uniaxial tension/compression tests under pulsed electric current, characterized by an instantaneous stress drop and subsequent transient hardening behavior. The simulated springback profiles were in good agreement with the measured V-bending test data, thus validating the proposed finite element modeling procedure.

An innovation for microstructural modification and mechanical improvement of TiAl alloy via electric current application

In this article, microstructural evolution during the solidification of Ti-48Al-2Cr-2Nb with current density, as well as the formation mechanisms, are discussed, along with the impacts on microhardness and hot compression properties. The applied electric current promotes the solidification from the α primary phase to a largely β solidification in Ti-48Al-2Cr-2Nb. With an increase in supercooling, the solidification process have a tendency to change from an α-led primary phase to (α + β)-led primary phase. The primary dendrites, grain size, and lamellar spacing show a tendency to decrease first before increasing with increasing current density. Microhardness and high-temperature yield strength increase with a decrease in primary dendrite spacing, grain size, and lamellar spacing. Correlations between primary dendrite spacing, lamellar spacing, microhardness, yield strength, and current density are described by a fitting formula. An increase of α2 phase, due to the application of electric current, results in improved microhardness. The yield strength of Ti-48Al-2Cr-2Nb alloy increases linearly with microhardness. Yield stress increases with a decrease in microstructure parameters, in accordance with the Hall–Petch equation. The predominant modification mechanism with electric current application for TiAl solidification is the variation of supercooling and temperature gradients ahead of the mush zone due to Joule heating.

Evaluating the performance and membrane fouling of an electro-membrane bioreactor treating textile industrial wastewater

This study evaluated for the first time the performance and the membrane fouling behavior of a laboratory-scale electro-membrane bioreactor (EMBR) for the treatment of real textile wastewater. The EMBR was operated initially with no electrocoagulation process (control period) during 30 days (run I), and thereafter, the electrocoagulation was started, using the electrical current density of 10 A m−2 (run II) and 15 A m−2 (run III). The reactor performance on color removal was significantly improved by electrocoagulation process, attaining average efficiency of 50 and 70% in the experimental runs II and III. Similarly, the nitrification performance also was enhanced during the period with electrocoagulation, enabling an average NH4+–N removal efficiencies above 90% in the runs II and III. Activity batch assays have shown that autotrophic biomass exhibited a higher oxygen uptake rate during the electrocoagulation experiments, indicating that nitrifying activity increased in the EMBR over this period. Despite the substantial variation in the influent COD values, the COD removal efficiencies were practically constant (75–77%) throughout experimental period. This behavior indicates that the reactor exhibited a great resistance to shock loading, an important feature for the treatment of industrial wastewaters. Better mixed liquor filterability conditions were found during the electric current application, resulting in a lower membrane fouling rate and demanding a lower frequency of the membrane chemical cleaning process.