Different Kinds Of Electrodes Research Articles

Flexible electrodes for non-invasive brain–computer interfaces: A perspective

At the present time, brain–computer interfaces (BCIs) are attracting considerable attention due to their application potential in many fields. In this Perspective, we provide a brief review of flexible electrode technologies for non-invasive BCIs, mainly including two types of the most representative flexible electrodes: dry electrodes and semi-dry electrodes. We also summarize the challenges encountered by the different kinds of electrodes by comparing their strengths and weaknesses in terms of manufacturing scalability, applicability, comfort, contact impedance, long-term stability, and biocompatibility. In addition, we describe some advanced configurations and suggest potential applications for non-invasive BCIs based on flexible electrodes and consider future development prospects.

Pore-Scale Investigation of Coupled Two-Phase and Reactive Transport in the Cathode Electrode of Proton Exchange Membrane Fuel Cells

A three-dimensional multicomponent multiphase lattice Boltzmann model (LBM) is established to model the coupled two-phase and reactive transport phenomena in the cathode electrode of proton exchange membrane fuel cells. The gas diffusion layer (GDL) and microporous layer (MPL) are stochastically reconstructed with the inside dynamic distribution of oxygen and liquid water resolved, and the catalyst layer is simplified as a superthin layer to address the electrochemical reaction, which provides a clear description of the flooding effect on mass transport and performance. Different kinds of electrodes are reconstructed to determine the optimum porosity and structure design of the GDL and MPL by comparing the transport resistance and performance under the flooding condition. The simulation results show that gradient porosity GDL helps to increase the reactive area and average concentration under flooding. The presence of the MPL ensures the oxygen transport space and reaction area because liquid water cannot transport through micropores. Moreover, the MPL helps in the uniform distribution of oxygen for an efficient in-plane transport capacity. Crack and perforation structures can accelerate the water transport in the assembly. The systematic perforation design yields the best performance under flooding by separating the transport of liquid water and oxygen.

Testing and analysis of nanoparticles-based textrodes for physiological signals

The different kinds of electrodes to monitor the physiological parameters like heart rate, respiration rate, blood pressure, temperature etc. have become inevitable in the healthcare sector. The use of surface electrodes may be allergic to the skin, and the glue used here gets dehydrated over some time. Moreover, surface degradation of electrodes leads to poor acquisition of signal. Hence, the present-day monitoring systems fail to provide a high level of comfort to the users. To make the continuous monitoring system to be more reliable, textile-based wearable electrodes (textrodes) for ECG measurement device is proposed. The fabric in the textile electrode must be conductive to acquire the biosignals. The textiles are made conductive by coating them with a silver (Ag) and copper (Cu) nanoparticles. The poly (3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT: PSS) solution is also used to make the fabric conductive. Both are blended at certain ratios to enhance better conductivity. Silver nanoparticles and copper nanoparticles are produced by chemical reduction and solution reduction methods respectively. In both processes, sodium borohydride is used as a reducing agent. The presence of Ag and Cu nanoparticles is confirmed by UV and XRD analysis. The obtained UV range for silver and copper nanoparticles are 405 nm and 545 nm respectively. The skin impedance of the commercially available disposable electrodes offers 4KΩ. Based on experimentation, PEDOT: PSS coated cotton fabric offers the lowest impedance; thereby low signal to noise ratio (SNR) is achieved while acquiring ECG signal in a real-time environment. Followed by PEDOT: PSS, Ag and Cu coated cotton fabrics offer better impedance and SNR. The application of textrodes can be expanded continuously to meet people’s activity where the electronic product is expected to be integrated with garments as so thin and lightweight.

Comparative study analysis of practical EEG sensors in medical diagnoses

EEG records the brain's electrical function. It displays the difference in voltages from distinct sites of the brain over a period of time. It plays a major role in understanding the brain. It also helps to diagnose disorders related to sleep, and find the epileptogenic foci in the brain. Recording accurate EEG signals, however, comes with its own limitations. Gels applied to the scalp are abrasive in nature. Gels dry up over time, and also irritate the skin. There are different kinds of electrodes that record EEG signals with appreciable accuracy, keeping comfort and practicality in mind. Some of them are: dry electrodes, capacitive electrodes, electrodes with nanomaterials. The electrodes mentioned above are discussed in this paper. It discusses the advancement in the field of EEG. This paper shows the ease at which signals can be captured, using the aforementioned electrodes. Cheaper, more accessible EEG electrodes are making it possible to bring affordable healthcare outside the confines of the hospitals and clinics.

A Review On Electrode Materials in Microbial Fuel Cell Fabrication

Electrical energy needs in Nigeria are expected to continue to rise due to the rise in population. The use of petroleum as a source of energy still dominates till date, although oil reserves in Nigeria are increasingly being depleted. There is therefore the need to develop alternative source of sustainable energy, such as, Microbial Fuel Cell (MFC). Electrode materials are critical for microbial fuel cells (MFC) due to their influence in the construction as well as operational costs. In this study, we reviewed different kinds of electrodes used for the purpose of fabrication of MFC across the globe. The study shows that, most of electrode materials are carbon based perhaps due to their high conductivity, durability, eco-friendliness. While the likes Activated carbon and Biochar are selected for their surface area advantages, Graphenes, Carbon Nanotubes and Some Metals excel in the area of delivering high power density

Comparison between Intramuscular Multichannel Electrodes and Supramysial Multichannel Electrodes via EMG Measurements for Potential Use as Larynx Stimulation Electrodes: In Vivo Animal Analysis.

One of the most common causes for larynx paralysis is the injury of the recurrent laryngeal nerve which, among others, causes the paralysis of the posterior cricoarytenoideus muscle (PCA). Electrical stimulation of PCA offers an approach to retaining the function of the paralyzed larynx muscle. The study aim was to test the applicability of an intramuscular multichannel array electrode as a measuring electrode for myoelectrical potentials and as a possible electrode for stimulation, e.g., posterior cricoarytenoideus muscle stimulation. For this purpose, two different kinds of electrodes were compared. 42 intramuscular multichannel array electrodes and 11 supramysial multichannel electrodes were implanted into the triceps brachii muscle of rats. The triceps brachii muscle of rats is suitable to serve as a substitute muscle for the human PCA muscle in an in vivo animal model. It has the same striated muscle cells, is of comparable size, and fundamentally serves a similar function to the human PCA muscle during normal respiration. Walking and breathing are circular functions that cause minimal muscle fatigue when carried out steadily. In total, the myoelectrical activity of 6703 steps could be recorded, allowing a comparison and statistical analysis of the EMG amplitudes and EMG activation patterns. Small differences can be detected between the EMG signals of both electrode types which, however, can be explained physiologically. Both electrode types reveal the basic characteristics of the triceps brachii muscle activity, namely the muscle contraction strength and the coordination pattern. This indicates that the intramuscular electrode may be applied for a detailed analysis of the human larynx.

Gold Nanoparticle Embedded Modified MWCNT Electrodes for Electrochemical Detection of Arsenic in Water

Email of corresponding author: dipban@iitg.ac.in : We focus on electrochemical detection of arsenite and/or arsenate in water using different kinds of electrodes made from gold nanoparticle embedded on substituted multiwall-carbon-nanotubes (MWCNT). The CNTs were functionalised with thiol groups by reaction with cysteamine. Following this, three different electrodes were fabricated using thiol substituted MWCNTs, gold nanoparticle (Au NP) embedded thiol substituted MWCNTs, and magnetite doped Au NP embedded MWCNTs. Subsequently, effect of Au NPs on the electrodes in the selectivity and sensitivity of the sensor was studied. The aforementioned experiments suggest that the affinity of the arsenite ions towards the thiol groups were found to be magnified by the integration of an optimal amount of Au NPs. Further, addition of magnetite particles in the CNT matrix made the sensor more sensitive towards arsenic detection. The working principles, mainly the change of the surface potential, of the electrodes were characterized by surface potential microscopy (SPOM) study using atomic force microscopy (AFM). The study helped in the miniaturization of the arsenic sensor using screen printed commercial electrode system with a modification of the working electrode based on requirement as stated before. Interestingly, we extracted the electrochemical response using an open source Arduino UNO based potentiostat unit, as shown in Fig. 1, to translate the concept into a portable electrochemical arsenic sensor. Keywords: Arsenite/Arsenate sensor, electrochemical, Screen printed electrode, Gold nanoparticle, Arduino UNO. Figure 1

Rapid Prediction of the Open-Circuit-Voltage of Lithium Ion Batteries Based on an Effective Voltage Relaxation Model

The open circuit voltage of lithium ion batteries in equilibrium state, as a vital thermodynamic characteristic parameter, is extensively studied for battery state estimation and management. However, the time-consuming relaxation process, usually for several hours or more, seriously hinders the widespread application of open circuit voltage. In this paper, a novel voltage relaxation model is proposed to predict the final open circuit voltage when the lithium ion batteries are in equilibrium state with a small amount of sample data in the first few minutes, based on the concentration polarization theory. The Nernst equation is introduced to describe the evolution of relaxation voltage. The accuracy and effectiveness of the model are verified using experimental data on lithium ion batteries with different kinds of electrodes (LiCoO2/mesocarbon-microbead and LiFePO4/graphite) under different working conditions. The validation results show that the presented model can fit the experimental results very well and the predicted values are quite accurate by taking only 5 min or less. The satisfying results suggest that the introduction of concentration polarization theory might provide researchers an alternative model form to establish voltage relaxation models.

Methane production by a combined Sabatier reaction/water electrolysis process

This paper describes production of synthesis gas (syngas) and its optimization through a one-step innovative 1 kW prototype of alkaline water electrolysis (patented), using graphite electrodes and without gas separation (containing CO, CO2, H2 and small amounts of O2). The behavior of the syngas composition and flow rate has been studied and optimized, changing operational parameters such as temperature, pressure and current intensity, and testing two different kinds of electrodes. Afterwards, the best syngas composition has been sent into a catalytic reactor (filled with a bed of Ni/CaO-Al2O3 catalyst) in order to achieve methane production, at 1 bar and different temperatures.The main competitive advantage of this process lies in the built-in of an innovative technology product, from renewable energy (RE) power in remote locations, such as islands, villages in mountains as an alternative for energy storage for mobility constraints. In the catalytic reactor it was possible to achieve a CH4 yield of 25.5 %, a CO2 conversion into CH4 of 44.2% and a CH4 selectivity of 96.5%.

Bio-Fenton and Bio-electro-Fenton as sustainable methods for degrading organic pollutants in wastewater

Abstract In this paper, an overview of the bio-Fenton and bio-electro-Fenton processes for sustainable wastewater treatment is provided. These two methods have been used in recent years to treat many kinds of persistent pollutants while maintaining the sustainability in materials and power consumption compared to conventional methods, through efficient eco-designed systems. The different kinds of electrodes used for the bio-electro-Fenton are reviewed, along with the influencing factors affecting the efficiency of these methods, and the different designs used to construct the reactors. Moreover, the various organic pollutants from industrial sources, like effluents from textile and pesticides facilities, treated using these processes are also reported. However, the main challenge facing these technologies is to improve their performance, stability and lifetime to achieve more sustainable and cost-effective wastewater treatment on pilot and large scales. Hence, future perspectives and trends are discussed to overcome the drawbacks of these methods.

Performance of Microbial Fuel Cell to Generate Bioelectricity Uses Different Kinds of Electrode in the Fish Processing Wastewater

Microbial Fuel Cell (MFC) is one of the alternative technologies which can convert chemical energy to electrical energy through a catalytic reaction using microorganisms. The technology can be implemented for wastewater handling such as fish processing wastewater which contains highly in organic substances. The research objective was to measure the performance of MFC system using fishery processing wastewater in order to generate bioelectricity and to reduce its organic pollution load within a different material of the electrode. The electrode materials used were aluminum, iron, carbon graphite, and also the combination of aluminum and carbon graphite. The research carried out in three phases: production of fishery wastewater, assembly of MFC single chamber system and measurement of the bioelectricity produced. The bioelectricity power resulted during 120 hours of observation were 0.23V for aluminum, 0.17V for iron, 0.19V for carbon graphite, and 0.34V for the combination between aluminum and carbon graphite averagely. The MFC system can also decrease the organic load parameter of wastewater as much as total Nitrogen was 61%, BOD 30.11%, COD 59.34%, and total Nitrogen Ammonia 12.45%. The increasing of activated sludge biomass occurred on the last observation with MLSS and MLVSS values respectively 7,066.67 mg/L and 6,100 mg/L.

Dielectrophoretic effect on droplet dynamic behaviors in microchannels

Dielectrophoresis is of particular interest in droplet manipulation because of its ability to manipulate droplets based on their unique dielectric properties. With the help of different kinds of electrodes, the droplet dynamic behaviors can be manipulated to complete various tasks. In this work, both the experimental and numerical simulation methods are applied to find out a way to slow down the velocity of the droplets which is very helpful for droplets detection. For the experimental part, the microchannels are embedded with various kinds of electrodes near their microchannel walls instead of being arranged in the microchannel, and the direct current voltages are applied to the electrodes to generate a prescribed electric field intensity gradient in the longitudinal direction. A more accurate simulation model is made to analyze the mechanisms of the dielectric effect on the droplet dynamic behaviors in detail. The dynamic behaviors and dielectric characteristics of the microdroplets are investigated by studying the moving velocity, the deformation, the dielectrophoretic force and distributions of the electric field intensity. According to the results presented herein, both the dielectrophoretic force and interfacial tension have significant effects on the droplet dynamic behaviors. The method proposed in this work can manipulate the droplet velocity efficiently, and the velocity of the droplets can be decreased to one-fifth of the initial velocity. Therefore, it is important to focus on this method to make a contribution to droplet non-damage detection in biological and chemical experiments.

Redesign of a soft conductive rubber strip electrode for measurement of surface resistance according to IEC 60079-32-2 within the context of the PTB Ex Proficiency Testing Scheme

To ensure worldwide quality and homogeneity in the field of explosion protection, not only uniform rules in the form of IEC standards but also the active participation in interlaboratory comparisons are necessary. The “PTB Ex Proficiency Testing Scheme” is the first global proficiency testing program of its kind in the field of explosion protection. It serves as proof of competence and provides laboratories with a complete system for their own performance evaluation.In 2015, the program “Electrostatic Charge - Test Round 2015” was launched within the PTB Testing Scheme. The participants of the program performed surface resistance and transferred charge tests according to IEC 60079-0 and IEC 60079-32-2 on various types of test samples. The new standard IEC 60079-32-2 proposes different kinds of electrodes for the user, such as conductive silver paint electrodes, soft conductive rubber strip electrodes on spring-mounted metal tongues or conductive foam strips mounted on an insulating support, depending on the geometry of the sample. These different types of electrodes as well as the construction latitude for each electrode could lead to deviations between the results of different test laboratories due to better or worse electrode contact with the test sample.Therefore, the proficiency team and electrostatic experts at PTB decided to design an accurate and user-friendly electrode which meets the requirements of IEC 60079-32-2. This paper provides information about the electrodes' design as well as the results of comparable measurements.

Breakdown voltage of glow discharge of pin electrodes

One of the shortcomings of glow discharge tube is its high breakdown voltage. In this paper, 2-pin electrode, 3-pin electrodes and 4-pin electrode are fabricated. The breakdown voltages of glow discharge of these electrodes have been measured within the pressure range of 0.4–2.5 kPa. The breakdown voltages vary obviously for the different kinds of electrodes, and the maximum difference of the breakdown voltages is about 208 V. Electric fields of the electrodes are calculated and the results consist with the experimental results. It is concluded that the breakdown voltage can be significantly reduced by adjusting electrode structure without changing the distance between electrode pins. The proposed electrode structure has potential applications in devices of glow discharge.

Effects of changes in intracellular action potential on potentials recorded by single‐fiber, macro, and belly–tendon electrodes

Some myopathies are accompanied by abnormal calcium homeostasis. Electromyography (EMG) in such patients shows signs of normal or myopathic EMG when detected by a single-fiber electrode and abnormally increased values in macro EMG. As calcium accumulation might be accompanied by changes in intracellular action potential (IAP) and muscle-fiber propagation velocity, we simulated the effects of such changes on motor unit potentials (MUPs) recorded by different kinds of electrodes. We found that: (1) the requirements for what potential can be accepted as a single-fiber action potential (SFAP) are too rigorous; (2) macro MUP amplitude can increase while SFAP amplitude can decrease when there is an increase in the spatial length of IAP spike; and (3) changes in the second phase of a belly-tendon-detected MUP or M wave could be used for noninvasive detection of increased IAP depolarizing (negative) after-potential.

Fabrication of Superhydrophobic Surfaces by Electropolymerization of Thiophene and Pyrrole Derivatives

The electropolymerization of five-membered heterocycles like thiophene and pyrrole leads to the deposition of conductive and morphology-controlled films onto different kinds of electrodes. It involves many experimental parameters such as the chemical nature and concentration of the monomer and electrolyte, the solvent, the nature of electrode, the applied electrical conditions and the time considered. These electrosynthesis conditions determine to a large extent the structure, morphology and properties of the resulting polymer. By controlling them, it represents a straightforward method to obtain highly porous surfaces. The use of low surface energy alkyl or perfluoroalkyl chains together with the electropolymerization process allows the control of the two parameters that generally govern the wettability of a surface, i.e. the chemical composition and the microstructure of the surface, and affords an excellent method to reach very stable superhydrophobic surfaces with a low contact angle hysteresis.

Fabrication of insulator coatings for fusion reactor liquid lithium blankets

The development of insulating coatings is one of the most important subjects in fusion reactor liquid lithium blanket research and development. The compounds AlN, Y 2O 3 and Er 2O 3 are thought to be candidate materials for ceramic coatings because of their high electrical resistance and their high compatibility with liquid lithium. In this study, the coatings of these compounds were fabricated by the RF sputtering method, and their properties, thickness, composition ratio, impurities, crystallinity and resistivity were investigated. The coatings were polycrystalline and almost stoichiometric. Although the apparent resistivity data were scattered with different kinds of electrodes in the measurement, the coatings had enough high resistivity. After annealing, the crystallinity of the coatings became higher, but some cracks were observed on the surface of Y 2O 3 and Er 2O 3 coatings.

Voltametria de onda quadrada. Segunda parte: aplicações

The aim of this work is to discuss some selected applications of square wave voltammetry published in the last five years. The applications focused here cover several electroanalytical fields such as: determination of pesticides; molecules with biological activity; metals and other environmental pollutants. Special attention is given to the work developed in the Grupo de Materiais Eletroquimicos e Metodos Eletroanaliticos - IQSC - USP concerning the utilization of square wave voltammetry, with different kinds of electrodes, for the determination of pesticides in natural waters and active principles in pharmaceutical formulations. The new methodology is simple, fast and sensitive when compared with the traditional ones such as chromatography and spectrophotometry. The satisfactory results obtained provide alternative procedures for the quality control of drugs and the monitoring of pesticides in natural environments.

Ni/AlCl]-based hydrotalcite electrodes as amperometric sensors: preparation and electrochemical study

A study has been carried out to develop electrochemical devices based on the hydrotalcite (HT) [Ni/AlCl] suitable for the amperometric determination of oxidisable species. The amperometric sensors have been tested on methanol, mannitol and glucose substrates. The measured signal is an electrocatalytic current due to the oxidation of Ni(II) centres present in the brucite layers of HT to Ni(III) or Ni(IV). Different kinds of electrodes have been studied in terms of chemical and mechanical stability, lifetime, and simple regenerability of the surface. Cyclic voltammetry has been used to evaluate the electrochemical responses. The best performances have been achieved when HT particles were entrapped into an epoxy resin and the electrical contact was guaranteed by a carbon-based material.

Voltammetric analysis of ceftazidime after preconcentration at various mercury and carbon electrodes: application to sub-ppb level determination in urine samples

The electrochemical behavior of ceftazidime (CFZ) at four different kinds of electrodes viz. static mercury drop electrode (SMDE), controlled growth mercury electrode (CGME), glassy carbon electrode (GCE) and carbon paste electrode (CPE) has been presented. Optimal operational parameters have been selected for the drug preconcentration and determination in aqueous medium. Down to 2×10 −10 M CFZ is achieved as detection limit at the CGME. Modification of the CPE with polyvinyl alcohol (PVA) enhances both the sensitivity and selectivity for the drug accumulation and, therefore, its determination at very low levels. Application of the proposed method for CFZ analysis in spiked urine samples or those taken after metabolism has been easily assessed. Down to 1×10 −9 M CFZ (0.695 ng ml −1) could be easily achieved in such samples.