Bibliografías temáticas / Electrodes

Literatura académica sobre el tema "Electrodes"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 7 de julio de 2024

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Artículos de revistas sobre el tema "Electrodes"

Yashiro, Yusuke, Michitaka Yamamoto, Yoshihiro Muneta, Hiroshi Sawada, Reina Nishiura, Shozo Arai, Seiichi Takamatsu y Toshihiro Itoh. "Comparative Studies on Electrodes for Rumen Bacteria Microbial Fuel Cells". Sensors 23, n.º 8 (21 de abril de 2023): 4162. http://dx.doi.org/10.3390/s23084162.

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Microbial fuel cells (MFCs) using rumen bacteria have been proposed as a power source for running devices inside cattle. In this study, we explored the key parameters of the conventional bamboo charcoal electrode in an attempt to improve the amount of electrical power generated by the microbial fuel cell. We evaluated the effects of the electrode’s surface area, thickness, and rumen content on power generation and determined that only the electrode’s surface area affects power generation levels. Furthermore, our observations and bacterial count on the electrode revealed that rumen bacteria concentrated on the surface of the bamboo charcoal electrode and did not penetrate the interior, explaining why only the electrode’s surface area affected power generation levels. A Copper (Cu) plate and Cu paper electrodes were also used to evaluate the effect of different electrodes on measuring the rumen bacteria MFC’s power potential, which had a temporarily higher maximum power point (MPP) compared to the bamboo charcoal electrode. However, the open circuit voltage and MPP decreased significantly over time due to the corrosion of the Cu electrodes. The MPP for the Cu plate electrode was 775 mW/m2 and the MPP for the Cu paper electrode was 1240 mW/m2, while the MPP for bamboo charcoal electrodes was only 18.7 mW/m2. In the future, rumen bacteria MFCs are expected to be used as the power supply of rumen sensors.

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Asl, Sara Nazari, Frank Ludwig y Meinhard Schilling. "Noise properties of textile, capacitive EEG electrodes". Current Directions in Biomedical Engineering 1, n.º 1 (1 de septiembre de 2015): 34–37. http://dx.doi.org/10.1515/cdbme-2015-0009.

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AbstractThe rigid surface of the conventional PCB-based capacitive electrode produces an undefined distance between the skin and the electrode surface. Therefore, the capacitance introduced by them is uncertain and can vary from electrode to electrode due to their different positions on the scalp. However, textile electrodes which use conductive fabric as electrode surfaces, are bendable over the scalp. Therefore, it provides a certain value of the capacitance which is predictable and calculable accurately if the effective distance to the scalp surface can be determined. In this paper noise characteristics of textile electrodes with different fabric sizes as electrode’s surface and capacity calculations related to each size are presented to determine the effective distances for each electrode size.

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Khan, Waris N. y Rahul Chhibber. "Experimental investigation on dissimilar weld between super duplex stainless steel 2507 and API X70 pipeline steel". Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 235, n.º 8 (4 de mayo de 2021): 1827–40. http://dx.doi.org/10.1177/14644207211013056.

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This work investigates the microstructure and mechanical properties of 2507 super duplex stainless steel and API X70 high strength low alloy steel weld joint. This joint finds application in offshore hydrocarbon drilling riser and oil–gas pipelines. Coated shielded metal arc welding electrodes have been designed and extruded on 309L filler and their performance compared with a commercial austenitic electrode E309L. Filler 309L solidifies in ferrite-austenite (F-A) mode with a resultant microstructure comprising skeletal ferrites with austenite distributed in the interdendritic region. Results of tensile and impact tests indicate that weld fabricated with laboratory-developed electrodes has higher ductility and impact energy than the commercial electrode. The tensile strength and weld hardness of commercial electrodes are superior. The laboratory-made electrode’s microhardness is lower than the commercial electrodes, making the former less prone to failure. An alternative welding electrode coating composition has been suggested through this work and found to be performing satisfactorily and comparable to the commercially available electrodes.

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Aoyagi, Seiji, Masaru Kawanishi y Daiichiro Yoshikawa. "Multiaxis Capacitive Force Sensor and its Measurement Principle Using Neural Networks". Journal of Robotics and Mechatronics 18, n.º 4 (20 de agosto de 2006): 442–49. http://dx.doi.org/10.20965/jrm.2006.p0442.

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We propose a multiaxis capacitive force sensor consisting of one movable upper electrode on a plate and fixed lower electrodes on a substrate. The plate moves both vertically and horizontally when force is applied, and capacitance between upper and lower electrodes changes. This sensor uses the main electrical field between two directly facing electrodes and the fringe electrical field between diagonally opposed electrodes, making capacitance difficult to analyze. We simulated changes in nonlinear capacitance based on the upper electrode’s movement using the finite element method (FEM) and proved that capacitance is a function of the upper electrode’s displacement. We used a neural network to calculate the upper electrode’s displacement from capacitance. The neural network operates appropriately and calculated displacement error is within 0.5% of the full range. We proposed fabricating a practical force sensor consisting of planar capacitors making it compatible with surface micromachining and not requiring 3-D bulk micromachining, which simplifies fabrication, making it economical.

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Tanumihardja, Esther, Douwe S. de Bruijn, Rolf H. Slaats, Wouter Olthuis y Albert van den Berg. "Monitoring Contractile Cardiomyocytes via Impedance Using Multipurpose Thin Film Ruthenium Oxide Electrodes". Sensors 21, n.º 4 (18 de febrero de 2021): 1433. http://dx.doi.org/10.3390/s21041433.

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A ruthenium oxide (RuOx) electrode was used to monitor contractile events of human pluripotent stem cells-derived cardiomyocytes (hPSC-CMs) through electrical impedance spectroscopy (EIS). Using RuOx electrodes presents an advantage over standard thin film Pt electrodes because the RuOx electrodes can also be used as electrochemical sensor for pH, O2, and nitric oxide, providing multisensory functionality with the same electrode. First, the EIS signal was validated in an optically transparent well-plate setup using Pt wire electrodes. This way, visual data could be recorded simultaneously. Frequency analyses of both EIS and the visual data revealed almost identical frequency components. This suggests both the EIS and visual data captured the similar events of the beating of (an area of) hPSC-CMs. Similar EIS measurement was then performed using the RuOx electrode, which yielded comparable signal and periodicity. This mode of operation adds to the versatility of the RuOx electrode’s use in in vitro studies.

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Rashedul, Islam Md, Yan Zhang, Kebing Zhou, Guoqian Wang, Tianpeng Xi y Lei Ji. "Influence of Different Tool Electrode Materials on Electrochemical Discharge Machining Performances". Micromachines 12, n.º 9 (7 de septiembre de 2021): 1077. http://dx.doi.org/10.3390/mi12091077.

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Electrochemical discharge machining (ECDM) is an emerging method for developing micro-channels in conductive or non-conductive materials. In order to machine the materials, it uses a combination of chemical and thermal energy. The tool electrode’s arrangement is crucial for channeling these energies from the tool electrode to the work material. As a consequence, tool electrode optimization and analysis are crucial for efficiently utilizing energies during ECDM and ensuring machining accuracy. The main motive of this study is to experimentally investigate the influence of different electrode materials, namely titanium alloy (TC4), stainless steel (SS304), brass, and copper–tungsten (CuW) alloys (W70Cu30, W80Cu20, W90Cu10), on electrodes’ electrical properties, and to select an appropriate electrode in the ECDM process. The material removal rate (MRR), electrode wear ratio (EWR), overcut (OC), and surface defects are the measurements considered. The electrical conductivity and thermal conductivity of electrodes have been identified as analytical issues for optimal machining efficiency. Moreover, electrical conductivity has been shown to influence the MRR, whereas thermal conductivity has a greater impact on the EWR, as characterized by TC4, SS304, brass, and W80Cu20 electrodes. After that, comparison experiments with three CuW electrodes (W70Cu30, W80Cu20, and W90Cu10) are carried out, with the W70Cu30 electrode appearing to be the best in terms of the ECDM process. After reviewing the research outcomes, it was determined that the W70Cu30 electrode fits best in the ECDM process, with a 70 μg/s MRR, 8.1% EWR, and 0.05 mm OC. Therefore, the W70Cu30 electrode is discovered to have the best operational efficiency and productivity with performance measures in ECDM out of the six electrodes.

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Zhang, Rui, Zhiqiang Tian, Wenxiong Xi y Dongjing He. "Discharge Characteristics and System Performance of the Ablative Pulsed Plasma Thruster with Different Structural Parameters". Energies 15, n.º 24 (12 de diciembre de 2022): 9389. http://dx.doi.org/10.3390/en15249389.

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Under the given initial discharge energy level, altering the electrode structural parameters of the Ablative Pulse Plasma Thruster (APPT) is an effective way to improve the performance of the thruster. The purpose of this study is to reveal the underlying mechanism of the effect of changing the electrode structure parameters on the performance of the APPT system and to offer targeted support for researchers to optimize the design of APPT structure. With rectangular and tongue-shaped electrode configurations at various electrode flare angles, electrode lengths, and electrode spacings, the discharge characteristics, propellant ablation characteristics, and thruster performance of the APPT are systematically investigated. The underlying mechanism of how changing the electrode’s configuration parameter affects the performance of the thruster is identified by fitting and predicting the parameters of the APPT discharge circuit and system performance under various operating conditions. The results show that using tongue-shaped electrodes is more effective than using rectangular electrodes in terms of enhancing the inductive gradient of the electrodes, transferring more energy to the discharge channel, and increasing the squared integral value of the discharge current. As a result, the tongue-shaped electrode APPT performs better than the APPT with rectangular electrodes, as a consequence. The thruster’s performance can be enhanced for the same electrode configuration by increasing the electrode flare angle within a certain angle range; however, the improvement is extremely limited. Additionally, in the case of small electrode spacing, increasing the electrode flare angle can enhance the thruster’s performance more effectively.

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Garba, Elhuseini, Ahmad Majdi Abdul-Rani, Nurul Azhani Yunus, Abdul Azeez Abdu Aliyu, Iqtidar Ahmed Gul, Md Al-Amin y Ruwaida Aliyu. "A Review of Electrode Manufacturing Methods for Electrical Discharge Machining: Current Status and Future Perspectives for Surface Alloying". Machines 11, n.º 9 (12 de septiembre de 2023): 906. http://dx.doi.org/10.3390/machines11090906.

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In electrical discharge machining (EDM), the tool electrode is one of the substantial components of the system, and it ensures the success or failure of the EDM process. The electrode’s role is to conduct electrical charges and erode the workpiece to the desired shape. Different electrode materials have different impacts on machining. Certain electrode materials remove metal quickly but wear out rapidly, while others degrade slowly but the material removal is too slow. The choice of the electrode has an influence on both the mechanical properties, such as metal removal rate (MRR), wear rate, surface finish, surface modification and machinability, and the electrical properties, such as sparking initiation, time lag, gap contamination and process stability. There are factors to consider when fabricating an electrode, which include the type of workpiece materials, the metallurgical alloying of the materials, the choice of fabrication techniques, the intended use of the electrode, and material cost. Considerable challenges in EDM electrode fabrication have been reported, which include excessive tool wear for green compact electrodes, high toughness for sintered electrodes, and poor rigidity for additively manufactured electrodes. To address these issues, researchers have explored different manufacturing methods, such as casting, conventional machining, electrodeposition, powder metallurgy and additive manufacturing. In this paper, the various techniques attempted and adopted in EDM electrode manufacturing are analyzed and discussed. This paper also sought to give insight into EDM, its various forms, the dielectric fluid’s properties, EDM electrode’s size and shape, the effects of the electrode on the EDM process, material removal, electrode wear, present technologies for electrode fabrication, and the limitations of these technologies. Finally, directions for future research are highlighted.

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Carvalho, Daniel, Sandra Marques, Giorgia Siqueira, Armando Ferreira, João Santos, Dulce Geraldo, Cidália R. Castro, Ana V. Machado, Filipe Vaz y Cláudia Lopes. "Enhancing the Longevity and Functionality of Ti-Ag Dry Electrodes for Remote Biomedical Applications: A Comprehensive Study". Sensors 23, n.º 19 (8 de octubre de 2023): 8321. http://dx.doi.org/10.3390/s23198321.

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This study aims to evaluate the lifespan of Ti-Ag dry electrodes prepared using flexible polytetrafluoroethylene (PTFE) substrates. Following previous studies, the electrodes were designed to be integrated into wearables for remote electromyography (EMG) monitoring and electrical stimulation (FES) therapy. Four types of Ti-Ag electrodes were prepared by DC magnetron sputtering, using a pure-Ti target doped with a growing number of Ag pellets. After extensive characterization of their chemical composition and (micro)structural evolution, the Ti-Ag electrodes were immersed in an artificial sweat solution (standard ISO-3160-2) at 37 °C with constant stirring. Results revealed that all the Ti-Ag electrodes maintained their integrity and functionality for 24 h. Although there was a notable increase in electrical resistivity beyond this timeframe, the acquisition and transmission of (bio)signals remained viable for electrodes with Ag/Ti ratios below 0.23. However, electrodes with higher Ag content (Ag/Ti = 0.31) became insulators after 7 days of immersion due to excessive Ag release into the sweat solution. This study concludes that higher Ag/Ti atomic ratios result in heightened corrosion processes on the electrode’s surface, consequently diminishing their lifespan despite the advantages of incorporating Ag into their composition. This research highlights the critical importance of evaluating electrode longevity, especially in remote biomedical applications like smart wearables, where electrode performance over time is crucial for reliable and sustained monitoring and stimulation.

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Rahman, Fathur, Aulia Ghifari Nurlis, Damar Rastri Adhika y Suprijanto. "Fabrication and Evaluation of Carrageenan Based Bioplastic with Graphite and Ag-Nanoparticles Addition as Flexible Electrode for EMG Signal Measurement". Materials Science Forum 1104 (10 de noviembre de 2023): 15–24. http://dx.doi.org/10.4028/p-hkf5fy.

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Electromyography (EMG) is a method for measuring muscle biopotential signals for monitoring muscle activity. Electrodes are placed on the skin to capture EMG signals from muscles underneath. The most common electrodes used in clinical EMG measurement are Ag/AgCl electrodes in the form of metal plates coated with electrode gel. Electrode gel enhances the contact between the electrode’s metal plate and the skin since it is essential for a good measurement signal quality. Meanwhile, flexible electrodes are made from flexible conductive materials that can be adjusted to the contour of the skin surface; therefore, they can improve the measured biopotential signal quality. This study developed a carrageenan-based bioplastic with the addition of graphite and silver nanoparticles (AgNP) hybrid as a flexible electrode for EMG signal measurement. Fabrication of graphite and AgNP hybrid starts with the functionalization of the graphite powder in a mixture of HNO3 and H2SO4. Next, AgNPs were added using the electrochemical method by utilizing SnCl2 and functionalized graphite powder to form an Ag-Sn/Graphite (Graphite-AgNPs) hybrid conductive material. In order to incorporate conductive materials into bioplastic, the Graphite-AgNPs hybrid conductive material is then mixed into the carrageenan-based bioplastic mixture. It is found that 25% w/w addition of these conductive materials already gives good electrical conductivity. The best electrical conductivity value was determined by varying several conductive material types and concentrations. Finally, the EMG signal was measured with the bioplastic flexible electrodes, and the performance was compared with the commercial Ag/AgCl electrodes.

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Tesis sobre el tema "Electrodes"

Koep, Erik Kenneth. "A Quantitative Determination of Electrode Kinetics using Micropatterned Electrodes". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10524.

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Interfacial polarization resistances limit the performance of many thin film solid-state devices, especially at low temperatures. To improve performance, a fundamental understanding of the electrode kinetics that govern interfacial reaction rates must be developed. The goal of this work is to determine site-specific reaction mechanisms and the relative significance of various reactions in order to quantify optimum structural parameters within the cathode microstructure. Key parameters include the length of triple phase boundary (TPB), the quantity of exposed electrolyte/electrode surface, and the ratio of electrolyte to electrode material. These parameters, when studied in a specific system, can be incorporated into broader models, which will encompass the specific conductivity of each component to develop an optimized three-dimensional network. The emphasis of this work is the systematic control and manipulation of potential cathodic reaction sites in order to develop an understanding of the relative importance of specific reaction sites. Since the physical dimensions of reaction sites are relatively small, an approach has been developed that utilizes micro-fabrication (similar to that used in integrated-circuit fabrication) to produce small and highly controlled microstructures. Investigations were made into the nature and reactivity of Triple Phase Boundaries (hereafter TPB) through the use of patterned platinum electrodes since only the TPBs are active in these electrodes. After the processing details of micro-fabrication were established for the platinum electrodes, patterned Mixed-Ionic/Electronic Conducting (MIEC) electrodes were fabricated and studied using impedance spectroscopy to determine the contributions from the MIEC surface versus the TPB. Systematically changing the geometry of the MIEC electrodes (thickness and line width) allowed for the determination of the effect of ambipolar transport within the MIEC on the activity of MIEC surfaces versus the TPB. This information is critical to rational design of functionally graded electrodes (with optimal particle size, shape, porosity and conductivity). In addition to experimental studies, representative patterned electrode samples were made available for collaborative studies with surface scientists at other institutions to provide additional techniques (such as Raman Spectroscopy) on the carefully designed and controlled cathode surfaces.

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Nwosu, Nkem O. E. "Optimisation of electroless co-deposited solid oxide fuel cell electrodes". Thesis, Edinburgh Napier University, 2013. http://researchrepository.napier.ac.uk/Output/6448.

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Research already carried out on the use of the recently patented electroless nickel ceramic codeposition technique as a method of manufacturing solid oxide fuel cell (SOFC) electrodes has thus far indicated that, while functional electrodes can be manufactured by the technique, for optimum performance of the cell, amplification of the ceramic content of the coatings is still required. By mainly employing external agents such as surface active agents (surfactants) and magnetic fields (in a bid to aid ceramic particle stability), this research focused on the prospect of increasing the ceramic content of cermets co-deposited for use as SOFC electrodes. A total of 137 co-deposited samples were produced from different bath compositions. As a prelude to the study, the interactions between the ceramic powders used (yttria stabilised zirconia (YSZ) / lanthanum strontium manganate (LSM)) and the medium for the deposition process – the electroless nickel solution, were investigated by zeta potentiometry and ultraviolet-visible spectroscopy techniques. The results obtained from the studies led to a variation of a series of fundamental plating factors such as the ceramic bath loading and particle size of the powders. While the former was found to yield the highest ceramic content in the coating at a bath loading of 50 g/l, variation of latter notably produced mixed results. With the introduction of surfactants, it was noted that above the surfactant's (sodium dodecyl sulphate) critical micelle concentration, the incorporation of ceramic particles (YSZ) into the nickel matrix steadily increased to as much as 60 volume %. An inverse relationship was though found to exist between the coating thickness and the surfactant's bath concentration. Uniform coatings were found to be associated with low magnetic field strengths while although increased magnetic field strengths positively resulted in the amplification of particle incorporation into the coating, a lack of cohesion between the coating and the substrate – as indicated by coating flake-off, was observed at such strengths. It is suggested that because the magnetic flux was more dominant than the normally ionic plating mechanism, the particles co-deposited under the influence of a high magnetic field were relatively unstable after the coating process. Since LSM is alkaline in nature this work confirms that future research on the application of electroless nickel ceramic co-deposition as a method of manufacturing SOFC cathodes, be focused on the use of alkaline electroless nickel baths rather than the acidic solutions, which better suite YSZ particles.

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Seon, Hongsun 1965. "Electrode erosion and arc stability in transferred arcs with graphite electrodes". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=108637.

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Arc stability and erosion behavior were studied on a hollow graphite DC cathode in an argon atmosphere at atmospheric pressure. It was found that the arc stability is associated with the electron emission mode transition of the cathode operation. Estimation of current densities, SEM pictures, Fast Fourier Transform (FFT) of total voltage, and measurement of cathode surface temperature supported this. Stable arcs are in the thermionic emission regime while unstable arcs in the thermofield emission regime. Higher argon gas flow rate is believed to cause the shift of the mode from the thermofield emission to the thermionic emission by increasing the arc root temperature through steepening the thermal gradient at the arc root and increasing ionization phenomena inside the arc. Sharp cathode tip geometry usually leads to the thermionic emission while a rounded tip geometry encourages the thermofield emission. For the unstable arcs, the high voltage fluctuation resulted from the jumping of the arc root between different cathode spots and changes in the arc length. In the stable arcs, however, the voltage was almost constant because of the absence of arc jumping. The standard deviation of the voltage was used as the arc stability indicator and was less than 3 V for the stable arc in this transferred arc system.
The erosion rate of the cathode in this work ranged from 0.41 to 2.61 mug/C. At 150 A runs the arc stability strongly influenced the erosion rate; as the arc stability increased, the erosion rate decreased. Higher currents runs (300 and 400 A), however, showed the opposite trend because of the carbon vapor redeposition. The total erosion rates of 150 A runs were separated into the stable (Es) and the unstable (Eu) erosion rate. The Eu was more than 3 times higher in this work. It is believed that the thermofield emission of the unstable arcs produced more erosion because of the higher local heat flux to the cathode spots.

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Sand, Sara Catherine. "TiO2/CNT Composite Electrodes in Dye-Sensitized Solar Cell Electrodes". Ohio University Honors Tutorial College / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1492721176795399.

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Liu, Yong. "Novel nanostructured electrodes". Department of Chemistry - Faculty of Science, 2007. http://ro.uow.edu.au/theses/14.

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Nanotechnology provides an effective and direct way to create novel properties and phenomena through the reduction in material sizes without changing the materials’ chemical composition. A number of routes to the preparation of novel nanostructured electrodes were investigated in this thesis. These involve the formation of nanoporous opaline electrodes, three dimensional nanofibrous networks and the synthesis of flexible nanoelectrodes based on highly dense ordered aligned carbon nanotubes and conducting polymers. Excellent improvements with the use of nanostructures in a wide range of application areas such as methanol oxidation, photoelectrochemical cells, enzyme biosensors, cell culturing and energy storage are presented in this research work.Nanoporous opaline structures including inverse opals and opals were prepared by either electrodepositing Pt or sputter coating ITO onto self-assembled polystyrene (PS) synthetic opals, followed by the removal of the PS opal templates. A highly ordered dense nanoporous structure with the porous structure on the top (so-called Pt inverse opal) or with the porous structure on the bottom (so-called ITO opal) was consequently obtained after the removal of PS templates. The improvement in electrochemical area with the use of nanostructures was observed during electrochemical characterisation. The resultant nanostructured Pt inverse opal electrodes were employed in electro-oxidation of methanol. Compared with the Pt film electrode, the nanostructured Pt inverse opal electrode showed a higher catalytic performance and good stability with a 100 mV negative shift of the potential of methanol oxidation. The mesoporous ITO opal electrode was used as the substrate for the electrodeposition of polyterthiophene and the resultant structure was subsequently utilized in photoelectrochemical cells. An excellent power-conversion efficiency of 0.109% and an outstanding short circuit current density of 1470 μA•cm-2 for polyterthiophene deposited at room temperature were obtained; dramatically improved from the previous published work.Nanofibrous electrodes were fabricated from biomaterials (such as DNA and poly(styrene-β-isobutylene-β-styrene) (SIBS)) and single-walled carbon nanotubes (SWNTs) using the electrospinning technique. Initial studies quantitatively determined the influence of solution properties (such as the solution ionic conductivity, surface tension and viscosity) and process parameters (e.g. tip-to-collector distance, applied potential and the feed rate) on the electrospinning results. Results showed that good electrospun fibrous networks could be obtained from the solution with comparatively high conductivity and viscosity with low surface tension. It was also found that the average diameter of the electrospun fibers decreased with decreased feed rates, increased tip-to-collector distance and increase in the potential employed. With the addition of SWNT, both biomaterial nanofiber electrodes exhibited enhanced electrochemical properties. The resulting DNA based electrospun fiber electrode showed a broad linearity range and high sensitivity in enzyme biosensors. The SIBS/SWNT nanofibrous electrode demonstrated excellent biocompatibility and suitability for the growth of L-929 cells.Flexible, light and highly conductive nanostructured electrodes were prepared from aligned carbon nanotubes (ACNTs) and conducting polymers by coating with Pt coated poly(vinylidene fluoride) (PVDF) or poly(3,4-ethylenedioxythiophene) (PEDOT)/PVDF. Pt nanoparticles were subsequently electrodeposited on the ACNT/Pt/PVDF structure. The utilization of the nanostructured ACNT/conducting polymer electrodes in anodic methanol oxidation and as anodic materials in Lithium-ion batteries was demonstrated. Pt nanoparticles coated ACNT/Pt/PVDF electrode exhibited an outstanding electrochemical capacity (133 Fg-1) and amazing electrochemical surface area (143 m2g-1 for Pt nanoparticles). The Pt nanoparticles-ACNT/Pt/PVDF electrode also showed a 2.5 times higher steady current density for methanol oxidation when compared with the ACNT/Pt/PVDF electrode. A stable current density over a long period (more than 12 hours) was obtained. A 50% improvement in capacity during Lithium-ion battery tests when compared with a SWNT paper was obtained with the ACNT/PEDOT/PVDF electrode.Nanostructured flexible and conductive electrodes were also obtained from ACNTs and biomaterials (such as SIBS and poly(lactide-co-glycolide)). SWNTs or Pt were introduced to improve the conductivity. A significant improvement in electrochemical properties with the addition of Pt or SWNT was obtained. The biocompatibility of ACNTs, SWNTs and Pt was confirmed during cell culturing experiments.

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Maxwell, Virginia Margaret. "Ion-selective electrodes". Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329972.

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Laing, M. E. "Polymer coated electrodes". Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238164.

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Curran, Dominic. "Electrochemically modified electrodes". Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333807.

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Al-Lolage, Firas Ahmed Thanon. "Amperometric enzyme electrodes". Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/419053/.

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This thesis studies the conditions required to achieve direct electron transfer and the experimental tests needed to unequivocally demonstrate that it occurs. Many publications claim to observe direct electron transfer to redox enzymes (for example in the case of glucose oxidase) but the evidence presented is often incomplete and unconvincing. The first part of this thesis argues that the vast majority, if not all, of these claims of DET for GOx are incorrect. It presents results for glucose oxidase (GOx) adsorbed on multi‐walled carbon nanotubes (MWCNTs), a typical nanostructured GOx electrode, that clearly show that the surface redox peaks usually observed in these cases are due to free, adsorbed flavin and not due, as claimed, to DET to flavin within the enzyme. Also, the results can be explained by adsorption of enzymatically active GOx at the electrode surface and the detection of the decrease in the oxygen concentration at the electrode surface due to the enzyme catalysed oxidation of D‐glucose. The second part of this thesis establishes a flexible and structured method based on the use of site‐directed mutagenesis to introduce cysteine residues at specific locations on the enzyme surface followed by the reaction between the free thiol group and maleimide groups formed on the electrode surface to immobilise the mutated enzymes. It is preferable to immobilise redox proteins and enzymes in a specific orientation, but still with some flexibility to optimise reaction kinetics. Using cellobiose dehydrogenase (CDH) as a model system, multiwall carbon nanotube electrodes were first covalently modified with maleimide groups following a modular approach combining electrochemical surface attachment and solid phase synthesis methodology. Five CDH variants were used in this study, the CDH‐modified electrodes were tested for direct electron transfer (DET), showing high catalytic currents and excellent long‐term storage stability. A potential‐dependent Michaelis‐Menten model for the CDH modified GC/MWCNT has been constructed and a master equation employed to simulate the DET and MET experimental results. Several mechanisms were suggested to explain the DET and MET for CDH. The internal electron transfer (IET) has been shown to be the rate determining step in the proposed mechanism. This was confirmed by the simulated data along with the experimental results. The simulated data suggests the presence of two populations of immobilised enzymes, MET and DET enzyme. The validity of the aforementioned immobilisation method, was further examined. Three bilirubin oxidase (BOD) variants were used in this study, which were modified to bear a free cysteine residue in different positions at the surface of the enzyme, allowing fast and selective attachment to maleimide‐modified GC/MWCNT electrodes. The catalytic mechanism of O2 reduction by the Magnaporthe oryzae BOD covalently immobilized on multiwall carbon nanotube (MWCNT) electrodes, in the presence of Cl ̅ and at different pH, was electrochemically investigated. The results highlight for the first time the influence of chloride ions on the direct oxygen reduction by MoBOD as a function of pH.

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Eloul, Shaltiel. "Diffusion to electrodes". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:88c5f1d0-9f2f-49d5-b46d-6eeb5b7d4bfe.

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This thesis develops diffusion models for modern electrochemical experiments involving the transport of particles to electrodes and adsorbing surfaces. In particular, the models are related to the 'impact' method where particles stochastically arrive at an electrode and detected electrochemically. The studies are carried out using numerical simulations and also analytical methods. Chapter 1 is introductory and outlines some fundamental concepts in mass transport and kinetics, and their relation to electrochemical measurements which are of importance for the reader. Chapter 2 describes the numerical methods which are used for electrochemical simulations. Chapter 3 focuses on a specific two dimensional simulation system and the development of a high performance voltammetry simulation. Chapters 4 and 5 study the stochastic impacts of particles at an electrode surface. In Chapter 4, a 'diffusion only' model is developed using a probabilistic study and random walk simulations in order to provide expressions that can be used in so-called `impact' experiments. In Chapter 5, the practical cases of microdisc and microwire electrodes are investigated. Expressions for the number of impacts are developed and the concept of the lower limit of detection in ultra-dilute solutions is introduced. Then, a comparison study between the microwire electrode and the microdisc electrode explores a geometrical effect and its implications for experimental setups. In Chapter 6, a numerical and analytical study is developed to examine the effect of hindered diffusion as a particle moves close to an adsorbing surface. The study identifies the conditions under which this hindered diffusion is signiffcant even in a non-confined space. The study shows that the domination of hindered diffusion is strongly dependant on the sizes of both the particle and the target. The study focuses on a variety of target shapes and allows the number of hits/impacts to be estimated in practical 'impact' experiments. Moreover, a drastic effect on the calculation of the mean first passage time is observed for a sub-micron sized target, showing the importance of this effect not only for electrochemistry but also in biological systems. Chapters 7 and 8 investigate the properties of an adsorbing insulating surface adjacent to an electrode. In Chapter 7, a numerical study of the effect of 'shielding' by the insulating sheath is carried out. The study examines the in uence of this effect on the magnitude of the current in chronoamperometry experiments. Chapter 8 explores the case of reversible adsorption on the insulating surface for voltammetric enhancement by pre-concentration on the sheath surface. The results identify the conditions under which enhancement of the voltammetric signal can be observed. Finally, Chapter 9 looks at geometrical effects on the current response of insulating particles modified with an electroactive surface layer. Numerical models are developed to model the diffusion of charge transfer between electro-active sites on a modified surface of insulating particles. The current-time responses are simulated for particles with the shape of a sphere, a cube/cuboid, and a cylinder on an electrode. The characteristic currenttime responses are calculated for the various shapes. The observations show that the model can be utilised in experiments to determine the coverage or the diffusion coeficient of charge dissipation on modified insulating particles and, in some situations to identify the particle shape.

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Libros sobre el tema "Electrodes"

Einaga, Yasuaki, ed. Diamond Electrodes. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7834-9.

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Gupta, Ram K., ed. Organic Electrodes. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-98021-4.

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O, Finklea Harry, ed. Semiconductor electrodes. Amsterdam: Elsevier, 1988.

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Alkire, Richard C., Dieter M. Kolb, Jacek Lipkowski y Philip N. Ross, eds. Chemically Modified Electrodes. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2009. http://dx.doi.org/10.1002/9783527627059.

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Mikhelson, Konstantin N. Ion-Selective Electrodes. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36886-8.

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Mikhelson, Konstantin N. Ion-Selective Electrodes. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013.

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S, Licht, ed. Semiconductor electrodes and photoelectrochemistry. Weinheim: Wiley-VCH, 2002.

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Inzelt, György, Andrzej Lewenstam y Fritz Scholz, eds. Handbook of Reference Electrodes. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36188-3.

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G, Berger, Haschka F y United States. National Aeronautics and Space Administration, eds. Electrodes with fiber structure. Washington, D.C: National Aeronautics and Space Administration, 1986.

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Koryta, Jiří. Ions, electrodes, and membranes. 2^a ed. Chichester [England]: Wiley, 1991.

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Capítulos de libros sobre el tema "Electrodes"

de Groot, J. J. y J. A. J. M. van Vliet. "Electrodes". En The High-Pressure Sodium Lamp, 258–76. London: Macmillan Education UK, 1986. http://dx.doi.org/10.1007/978-1-349-09196-6_9.

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Böer, Karl W. "Electrodes". En Survey of Semiconductor Physics, 998–1021. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2912-1_31.

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Poddar, Asmita, Madhab Roy y Sanjib Bhattacharya. "Electrodes". En Lithium Ion Glassy Electrolytes, 137–46. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3269-4_13.

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Lauth, Jakob SciFox. "Electrodes". En Physical Chemistry in a Nutshell, 173–87. Berlin, Heidelberg: Springer Berlin Heidelberg, 2023. http://dx.doi.org/10.1007/978-3-662-67637-0_12.

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Lenarz, T., R. D. Battmer, J. E. Goldring, J. Neuburger, J. Kuzma y G. Reuter. "New Electrode Concepts (Modiolus-Hugging Electrodes)". En Advances in Oto-Rhino-Laryngology, 347–53. Basel: KARGER, 2000. http://dx.doi.org/10.1159/000059209.

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Giszter, Simon F., Taegyo Kim y Almut Branner. "Braided Electrodes". En Encyclopedia of Computational Neuroscience, 426–29. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4614-6675-8_590.

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Fujihira, Masamichi. "Modified Electrodes". En Topics in Organic Electrochemistry, 255–94. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4899-2034-8_6.

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De Beer, Dirk. "Micro-Electrodes". En Immobilized Cells, 85–100. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-56891-6_10.

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Boutros, Nash N. "Special Electrodes". En Standard EEG: A Research Roadmap for Neuropsychiatry, 21–25. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-13867-1_3.

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Duffy, Frank H., Vasudeva G. Iyer y Walter W. Surwillo. "Recording Electrodes". En Clinical Electroencephalography and Topographic Brain Mapping, 46–53. New York, NY: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4613-8826-5_7.

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Actas de conferencias sobre el tema "Electrodes"

Lai, Chien-Hsun y Yuan-Fang Chou. "Surface Acoustic Waves in Piezoelectric Half Space With Periodic Surface Electrodes". En ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12127.

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Surface acoustic waves of piezoelectric half space with periodic surface electrodes are investigated. Since the boundary has periodic character, Bloch’s theorem and plane wave expansion method are employed in the analysis. Modeling the periodic electrode’s mechanical effects and electric boundary conditions of short grating and open grating are major tasks. Verification is performed on a 128°YX-LiNbO3 substrate covered by aluminum electrodes. Cases of different electrode aspect ratios are also investigated. Comparisons of dispersion curves corresponding to different boundary conditions are given. The effect of electrode aspect ratio on band gap width is obvious. The developed solution scheme finds the dispersion relations and propagation modes very efficiently and accurately.

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Gao, Feng, Jianmin Qu y Matthew Yao. "Conducting Properties of a Contact Between Open-End Carbon Nanotube and Various Electrodes". En ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11117.

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The carbon nanotube (CNT) is becoming a promising candidate as electrical interconnects in nanoscale electronics. This paper reports the electronic structure and the electrical conducting properties at the interface between an open-end single wall CNT (SWCNT) and various metal electrodes, such as Al, Au, Cu, and Pd. A simulation cell consisting of an SWCNT with each end connected to the metal electrode was constructed. A voltage bias is prescribed between the left- and right-electrodes to compute the electronic conductance. Due to the electronic structure, the electron density and local density of states (LDOS) are calculated to reveal the interaction behavior at the interfaces. The first-principle quantum mechanical density functional and non-equilibrium Green’s function (NEGF) approaches are adopted to compute the transport coefficient. After that, the voltage-current relation is calculated using the Landauer-Buttiker formalism. The results show that electrons are conducted through the electrode/CNT/electrode two-probe system. The contact electronic resistance is calculated by averaging the values in the low voltage bias regime (0.0–0.1 V), in which the voltage–current relationship is found to be linear. And the electrical contact conductance of electrode/CNT/electrode system show the electrode-type dependent, however, the amplitude for different electrodes is of the same order.

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Kazemi, P. Zangeneh, P. Ravi Selvaganapathy y Chan Y. Ching. "Development of Electrohydrodynamic Micropumps With Micropillar Electrodes". En ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18186.

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Electrohydrodynamic (EHD) micropumps with three-dimensional 50μm × 50μm micropillar electrodes were fabricated and tested in this study. Two basic electrode configurations were investigated: (i) micropillar emitter and collector electrodes (symmetric) and (ii) micropillar emitter and planar collector electrodes (asymmetric). The micropumps were fabricated using chromium/gold planar electrodes with 3-D Nickel micro-pillars on a glass substrate that was integrated within a 100 μm high PDMS microchannel. The effect of the spanwise micropillar spacing spacing on the pump performance was determined. The pumps were tested using HFE-7100 as the working fluid for the maximum pressure generation under a no flow condition. The micropumps with the asymmetric electrode design generated a significantly higher pressure head and flow rate than the corresponding micropumps with symmetric electrode configuration for the same applied voltage, with lower power consumption. A decrease in the spanwise spacing of the micropillar electrodes increased the pump performance for the symmetric configuration, while the performance decreased for the asymmetric configuration.

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Zangeneh Kazemi, Pouya, Ponnambalam Ravi Selvaganapathy y Chan Y. Ching. "Microfabricated EHD Pumps With High Aspect Ratio Electrodes". En ASME 2007 5th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2007. http://dx.doi.org/10.1115/icnmm2007-30140.

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This work presents the design, fabrication and testing of electrohydrodynamic (EHD) micropumps with three dimensional (3-D) electrodes. It is known that the body force on the fluid due to an electric field is increased by increased injection of charges. In this design, 3-D micro pillars are used electrodes to provide high electrode-fluid contact area and to improve charge injection. Three different electrode designs were used to investigate the effect of different parameters, such as electrode spacing and pillars size, on the pump performance. The electrodes were fabricated using nickel, and were integrated into a microchannel of dimensions 22mm × 5mm × 100μm. The micropumps were tested under a no-flow condition with ethanol as the working fluid. The preliminary results suggest that the new 3-D electrodes improve pump performance over pumps with 2-D planar electrodes. A maximum pressure head of 780 Pa was achieved at an applied voltage of 150 V with the 3-D electrodes.

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Goundar, Jowesh Avisheik, Qiao Xiangyu, Ken Suzuki y Hideo Miura. "Improvement in Photosensitivity of Dumbbell-Shaped Graphene Nanoribbon Structures by Using Asymmetric Metallization Technique". En ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-69917.

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Abstract The existence of Schottky barrier between the semiconductive graphene nanoribbon (GNR) and the metallic electrodes at its both ends causes a major hurdle in the development of GNR based devices. Here, a dumbbell-shape GNR structure was proposed to solve the problem. This structure consisted of a semiconductive GNR and wide metallic GNR at both ends. The ohmic contact between the wide metallic GNR and metallic electrode was easily achieved. Furthermore, an effective mechanism to enhance electronic band properties of the dumbbell-shape GNR structure by using asymmetric metallization technique is employed. To achieve this, two different metallic electrodes were introduced, Platinum (Pt) and Titanium (Ti), at each end of the GNR channel to break the symmetry in the Schottky barrier at both ends. The asymmetric difference in the Schottky barrier at the electrode/GNR interface at each ends allows for an efficient directional flow of electrons, effectively separating the photo-generated carriers. The individual contributions at each electrode/GNR interface were summed up resulting in a larger absolute photo-induced current. The electron transfer characteristics of the DS-GNR-FET was studied under an irradiation of a light source with a wavelength of 632.8-nm at room temperature. The developed 70-nm DSGNR-FET showed a significantly larger and enhanced photosensitivity of about 1.6 × 107 A/W.m2 as compared to the device fabricated with identical metallic electrodes as the source and drain electrodes.

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Samiei, Ehsan y Mina Hoorfar. "Modifying Electrode Geometry for Unequal Droplet Splitting in Digital Microfluidics". En ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66844.

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In the present study, unequal droplet splitting is performed simply by modifying the electrode geometry: an electrode is divided into four small squares or four narrow sub-electrodes which are surrounded by regular spatial electrodes. Two possible configurations are studied for the narrower modified electrodes in which the narrow sub-electrodes are i) parallel, and ii) perpendicular to the flow direction. By actuating one (or more) sub-electrodes on one side and a spatial electrode on the other side of the droplet reproducible unequal splitting was achieved without a need for a complicated control system. In addition to reproducibility, the proposed approach offers a great deal of flexibility by splitting the droplet (or dispense a droplet) to different volumes based on the number of the actuated sub-electrodes.

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Khabbazi, Ali Ebrahimi y Mina Hoorfar. "Modeling of Microfluidic Fuel Cells With Flow-Through Porous Electrodes". En ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33220.

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This paper presents a modeling of a microfluidic fuel cell with flow-through porous electrodes using vanadium redox couples as the fuel and oxidant. There are advantages associated with the use of vanadium redox species in microfluidic fuel cell: 1) vanadium redox couples have the possibility of producing high open-circuit potential (up to 1.7 V at uniform PH [1]); 2) they have high solubility (up to 5.4 M) which causes more species available to the electrodes; 3) they do not require metal catalyst for electrochemical reactions so the reactions take place on the bare carbon electrodes. This characteristic of the vanadium redox couple make them a great candidate as reactants as they do not need expensive catalyst coatings on the electrodes. The fuel and the oxidant can be brought into contact with the electrode in two different ways: flowing over the electrodes or flowing through the electrodes. In the presented fuel cell design, the vanadium redox species are forced to flow through the porous electrodes. They finally come to meet each other in the middle microchannel and establish a side-by-side co-laminar flow traveling down the channel. In this paper, the effect of the inlet velocity and electrode porosity has been investigated. As it is expected, the higher velocity results in the higher power densities. For the porosity, however, there is an optimum value. In essence, there is a trade-off between the available electrode surface area and electric conductivity of the solid phase (i.e., the porous carbon electrode). The modeling shows that a porous electrode with a 67% porosity results in the highest power output.

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Koraishy, Babar M., Sam Solomon, Jeremy P. Meyers y Kristin L. Wood. "Parametric Investigations of Direct Methanol Fuel Cell Electrodes Manufactured by Spraying". En ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54824.

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Manufacture of fuel cell electrodes by the thin-film method was originally proposed by Wilson et al. [1, 2] for proton-exchange membrane fuel cells (PEMFCs). This technology was subsequently utilized for the manufacture of direct methanol fuel cell (DMFC) electrodes by Ren et al. [3]. Key processing steps in the thin-film process are catalyst ink formulation and its application. The catalyst ink is typically composed of supported or unsupported catalysts, binder (ionomer), solvents and additives. Rheological properties of the ink, amount of binder, and choice of solvents are tuned to match the particular ink application process used to fabricate the electrode, as each coating process has its own unique requirements. Besides affecting the coating process, the choice and ratios of these components can significantly affect the electrochemical performance of the electrode. In this study, catalyst inks are designed and investigated for the spraying process, for utilization in the continuous fabrication of DMFC electrodes. For this purpose, the effect of the binder (ionomer) content on the performance of the electrodes is studied in detail. Decal-transfer electrodes are fabricated on a custom-built automated spraying apparatus with individually specified anode and cathode binder contents, and assembled to form a catalyst coated membrane (CCM) type membrane electrode assembly (MEA). These electrodes are rigorously tested to specifically identify their electrochemical performance, catalyst utilization and electrode morphology.

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Hollinger, Adam S., Michael G. Willis y Daniel G. Doleiden. "Model-Based Analysis of Electrode Design in a Direct Methanol Microscale Fuel Cell". En ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2015 Power Conference, the ASME 2015 9th International Conference on Energy Sustainability, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/fuelcell2015-49496.

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The performance of microscale fuel cells with high-aspect-ratio electrodes, defined as the ratio of electrode length to width, is often limited by the depletion of fuel along the length of the anode. Here we present a mathematical model to study electrode aspect ratio in a direct methanol microscale fuel cell. The model is supported with experimental data to show that low-aspect-ratio electrodes achieve higher power densities via improved mass transport to electrodes. The influence of electrode width on overall cell performance was investigated by varying the catalyst deposition region in low-aspect-ratio electrodes. The performance of our experimental fuel cell is consistent with our modeling studies, achieving a maximum power density of 25.3 mW/cm2 at room temperature with 1 M methanol. The model presented here can be used to further improve the geometric design of electrodes in a microscale fuel cell.

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Zhang, Xuyang, Song Luo, Hongtan Liu y Conghua Wang. "Numerical Studies of the Effectiveness of Electrodes With Conductive Dots in Flow Batteries". En ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65931.

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In flow batteries generally the entire surface of the electrodes are conductive. Due to the highly corrosive nature of the electrolytes of many types of flow batteries there exists a dilemma in choosing electrode materials: highly corrosion resistant materials have very high cost and low cost materials have low corrosion resistance and thus low durability. To overcome this difficulty, a novel design of electrodes with conductive dots and corrosion resistant film is proposed [1]. Such electrodes can be made of low-cost base metals covered with corrosion resistant film and evenly distributed conductive dots, which can be made of highly corrosion resistance material such as gold, titanium, etc. Since the area covered by the highly corrosion resistance metals can be only a small percentage of the total electrode area the cost of the electrode can be relatively low. In this study, numerical simulations have been performed to study the effectiveness of such a design. In this work, lead-acid flow batteries are used as a model for redox flow batteries. The results from the electrode with conductive dots are compared with those from conventional electrodes. When conventional electrodes are used, the entire electrode surface is active for electrochemical reactions. When redox reactions occur under charging and discharging cycles, the redox species are consumed very fast and the electrolyte concentrations on the electrode surface decrease sharply from those in the bulk flow, leading to sharp decrease in reaction rate along the flow direction. When electrodes with conductive dots are used, though the active area is much smaller, reaction rates in the down-stream are similar to those in the upstream. This is due to the recovery of electrolyte concentrations in the non-active area surrounding the conductive dots, mainly from diffusion. The more uniform reaction rates from the upstream to the downstream results in much higher average current density per unit active area. Thus, even though the active area of the electrode with conductive dots is much smaller, the total reaction rate per unit apparent electrode area is not much lower. The modeling results show that the electrodes with conductive dots are highly effective even when the area covered by the conductive dots is only a few percent of the total electrode area.

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Informes sobre el tema "Electrodes"

Weaver, R. y J. Ogborn. CGX-00-005 Cellulosic-Covered Electrode Storage - Influence on Welding Performance and Weld Properties. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), enero de 2005. http://dx.doi.org/10.55274/r0011816.

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Cellulosic-covered electrodes have been used for shielded metal arc welding (SMAW) circumferential welding of line pipe over many decades. They are characterized by electrode coverings containing organic matter. Unlike low hydrogen SMAW electrodes that achieve optimum results at low covering moisture levels, cellulosic-covered electrodes require much higher covering moisture levels for proper operation. For example, pipe welders have been known to deliberately expose electrodes to the weather, or even dip them in water prior to use. There are suggestions that high incidents of hydrogen assisted cracking (HAC) might be associated with low moisture levels in the cellulosic-covered electrodes used. This suggests further that storage and handling practices based on conventional wisdom in the field may not be sufficient as the industry transitions to more demanding applications and higher-strength materials. Consequently, this work was undertaken to develop more definitive information on the performance of cellulosic-covered electrodes for three purposes: � determine the influence of various storage and handling practices on electrode covering moisture, � determine the influence of covering moisture on electrode operability, weld metal chemical composition, and weld hardness, and � develop more definitive guidelines for cellulosic-covered electrode storage and handling practice. Three different E8010 type electrodes (one E8018-G and two E8018-P1) were subjected to various storage conditions - temperatures from -40�C (-40�F) to 66�C (150�F), and time periods up to 196 hours. As the temperature increased there was a tendency for lower electrode covering moisture levels with corresponding increases in weld metal alloy content (particularly Mn, Si, and Ti), increased weld hardness, increased weld strength, and higher tendency to HAC. Variations in electrode operation were also noted.

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Tobin J. Marks, R.P.H. Chang, Tom Mason, Ken Poeppelmeier y Arthur J. Freeman. ENGINEERED ELECTRODES AND ELECTRODE-ORGANIC INTERFACES FOR HIGH-EFFICIENCY ORGANIC PHOTOVOLTAICS. Office of Scientific and Technical Information (OSTI), noviembre de 2008. http://dx.doi.org/10.2172/940916.

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Fiore y Boring. L52233 Evaluation of Hydrogen Cracking in Weld Metal Deposited Using Cellulosic-Coated Electrodes. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), octubre de 2006. http://dx.doi.org/10.55274/r0010378.

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Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for "stovepipe" welding of pipelines because they are well suited for deposition of pipeline girth welds and are capable of high deposition rates when welding downhill. Despite advances in mechanized welding technology, development of low-hydrogen self-shielded flux-cored arc welding (FCAW) consumables, and substantial improvement of basic-coated low-hydrogen vertical-down shielded metal arc welding (SMAW) electrodes, manual pipeline welding using cellulosic-coated electrodes is still widely utilized throughout the world. Cellulosic-coated electrodes are also used for critical applications in offshore pipeline construction such as tie-in welds and repair welds.Hydrogen-assisted cracking can occur in both the weld metal and heat-affected zone (HAZ) regions of a welded joint, although HAZ hydrogen cracking is more common. Extensive work was undertaken in the 1970s and 1980s to study HAZ hydrogen cracking, and guidelines were developed to avoid HAZ hydrogen cracking by controlling heat input and preheat. Improvements in steelmaking practice and the trend toward leaner chemistries have also helped to alleviate HAZ hydrogen cracking. The primary objectives of this project are to further define the conditions that can lead to hydrogen cracking in weld metal deposited using cellulosic-coated electrodes, in terms of operator preference (arc length), electrode properties, power supply selection, and materials handling. The results of the project are being used to develop welding guidelines, and if applicable, re-hydration guidelines to prevent weld metal hydrogen cracking.

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Pintauro, Peter. Fuel Cell Membrane Electrode Assemblies with Ultra-Low Pt Nanofiber Electrodes. Office of Scientific and Technical Information (OSTI), abril de 2024. http://dx.doi.org/10.2172/2331465.

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Greg M. Swain, PI. Metal/Diamond Composite Thin-Film Electrodes: New Carbon Supported Catalytic Electrodes. Office of Scientific and Technical Information (OSTI), marzo de 2009. http://dx.doi.org/10.2172/948861.

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Heller, Adam. Implantable Biofuel Cell Electrodes. Fort Belvoir, VA: Defense Technical Information Center, julio de 2002. http://dx.doi.org/10.21236/ada403772.

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Yeager, E. y S. Gupta. Electrocatalysts for oxygen electrodes. Office of Scientific and Technical Information (OSTI), octubre de 1989. http://dx.doi.org/10.2172/7011191.

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Yeager, E. B. Electrocatalysts for oxygen electrodes. Office of Scientific and Technical Information (OSTI), octubre de 1991. http://dx.doi.org/10.2172/5850798.

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Wingard, Lemuel B. y Jr. Enzyme Cofactor Modified Electrodes. Fort Belvoir, VA: Defense Technical Information Center, febrero de 1986. http://dx.doi.org/10.21236/ada165604.

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Yeager, E. Electrocatalysts for oxygen electrodes. Office of Scientific and Technical Information (OSTI), octubre de 1990. http://dx.doi.org/10.2172/5958703.

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