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Electrode Configurations (electrode + configuration)

Distribution by Scientific Domains

Engineering	40%
Chemistry	40%
Earth and Environmental Science	20%

Selected Abstracts

Lactate Biosensor Based on Hydrotalcite-Like Compounds: Performances and Application to Serum Samples

ELECTROANALYSIS, Issue 22 2009
Irene Carpani
Abstract A lactate biosensor based on lactate oxidase supported onto a hydrotalcite, electrochemically deposited on a platinum surface, was developed for the first time. For the best electrode configuration, a linear response up to 0.8,mM, with a limit of detection of 14,,M and a sensitivity of 91,mA M,1,cm,2, was obtained. The influence of some interferents due to the oxidation of hydrogen peroxide (at +0.35,V vs. SCE) was also studied. By controlling carefully the experimental conditions, the determination of lactate in a commercial serum sample in the presence of interferents was successfully accomplished. [source]

Influence of needle tip distance on barrier discharge and ozone generation for multiple needle-and-plane electrode configuration

ELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 7 2010
Hideki Ueno
Abstract The relationship between the barrier discharge characteristics and ozone generation on application of an AC voltage in a triple needle-plane configuration has been investigated for various distances among the triple needle tips (d=0 to 7.0 mm) with a constant distance between the needle tip and the plane (g=3.0 mm) in dry air. The characteristics of the barrier discharge and ozone generation depend on the needle tip distance. It is considered that the influence is caused by the presence of space charge and accumulated charge, as suggested by discharge images taken by a still camera and a CCD camera. The ozone generation efficiency is also estimated from the power consumption and the ozone concentration. It is found that when the distance among the triple needle tips is small, the above influence is strengthened. In this case, the ozone generation efficiency is improved. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(7): 32,41, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10289 [source]

The role of methylnaphthalene in EHV cable oil as related to oil breakdown and discharge velocity

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2002
A. Al-Sulaiman
This experimental investigation explores the effect of high voltage lightning surges on the insulating oil used in the oil filled extra high voltage cables that serve electric power networks worldwide. Using non-uniform electrode configuration, the breakdown voltage and corresponding discharge propagation velocities in oil samples that are doped with trace amounts of 1-Methylnaphthalene are investigated under both polarities of applied stresses in gap spacing of up to 10 mm. Two distinct ranges of additive concentrations are observed which effect these characteristics. Generally, the positive discharge growth decreases with increase in gap spacing while the negative ones show opposite behaviour. Anomalous behaviour of discharge growth is observed at an optimum concentration of additive, as it attains supersonic velocity which increases with the increase in gap spacing. A correlation between the positive impulse breakdown voltage and the discharge propagation velocity is also established. [source]

Effect of different electrode configurations on the migration of copper ions during the electrokinetic remediation process

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009
Juan Almeira
Abstract Electrokinetic remediation (EKR) is becoming a popular technique for removal of heavy metals from polluted soils, but its low efficiency induced from high pH area should be improved. It is known that the proper arrangement of electric field direction and intensity may influence the migration of H+ and OH, by direction and distance, which means that basic and acid zones can be optimized through electric field orientation arrangement. The aim of this work is to study the influence of the arrangement of electrodes on acid/basic zone, minimizing basic area and maximizing acid area in the soil. In this paper, five soil samples named TQ1, TQ2, TQ2, B55, and B60 were treated by EKR with different two-dimensional (2D) electrodes arrangement, in order to investigate the effect of electrode configurations on the distribution of pH and copper ions removal. Based on the results of copper removal, energy consumption, effective area, and the percentage of acid, basic and pH jump area, the best electrode configuration would be a cathode,anode,cathode arrangement with 60° angle. It can also be seen from the results that only in the area of pH < 4, copper ions could be removed effectively. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

A numerical comparison of 2D resistivity imaging with 10 electrode arrays

GEOPHYSICAL PROSPECTING, Issue 5 2004
Torleif Dahlin
ABSTRACT Numerical simulations are used to compare the resolution and efficiency of 2D resistivity imaging surveys for 10 electrode arrays. The arrays analysed include pole-pole (PP), pole-dipole (PD), half-Wenner (HW), Wenner-, (WN), Schlumberger (SC), dipole-dipole (DD), Wenner-, (WB), ,-array (GM), multiple or moving gradient array (GD) and midpoint-potential-referred measurement (MPR) arrays. Five synthetic geological models, simulating a buried channel, a narrow conductive dike, a narrow resistive dike, dipping blocks and covered waste ponds, were used to examine the surveying efficiency (anomaly effects, signal-to-noise ratios) and the imaging capabilities of these arrays. The responses to variations in the data density and noise sensitivities of these electrode configurations were also investigated using robust (L1 -norm) inversion and smoothness-constrained least-squares (L2 -norm) inversion for the five synthetic models. The results show the following. (i) GM and WN are less contaminated by noise than the other electrode arrays. (ii) The relative anomaly effects for the different arrays vary with the geological models. However, the relatively high anomaly effects of PP, GM and WB surveys do not always give a high-resolution image. PD, DD and GD can yield better resolution images than GM, PP, WN and WB, although they are more susceptible to noise contamination. SC is also a strong candidate but is expected to give more edge effects. (iii) The imaging quality of these arrays is relatively robust with respect to reductions in the data density of a multi-electrode layout within the tested ranges. (iv) The robust inversion generally gives better imaging results than the L2 -norm inversion, especially with noisy data, except for the dipping block structure presented here. (v) GD and MPR are well suited to multichannel surveying and GD may produce images that are comparable to those obtained with DD and PD. Accordingly, the GD, PD, DD and SC arrays are strongly recommended for 2D resistivity imaging, where the final choice will be determined by the expected geology, the purpose of the survey and logistical considerations. [source]

Selective control of voltage polarity in a single-chamber solid-oxide fuel cell using the same catalytic electrodes with different sizes

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 5 2008
Akiyoshi Nagata Member
Abstract The selective control of the voltage polarity in a single-chamber solid-oxide fuel cell (SC-SOFC) constituting the anode and cathode arranged at the same electrolyte surface of yttria-stabilized zirconia (YSZ) or samaria-doped ceria (SDC) and which can operate in a flowing mixture of hydrogen and oxygen is discussed on the basis of the dissociation and adsorption reactions due to the catalytic materials and electrode configurations. The open circuit voltage (OCV) of SC-SOFC showed the highest value when the H2:O2 ratio was around 2:1, which might be equal to the mol ratio of oxygen and hydrogen based on the reaction of water formation by the electrochemical reaction in the cell. The voltage polarity of the cell using the Pt and LSM (La0.7Sr0.3MnO3) catalysts was the same as in the conventional SOFC such that in the Pt catalysis the anode became negative whereas in the LSM catalysis the cathode was independent of the electrode configurations. In SC-SOFC using the same Pt catalyst, the larger Pt electrode functioned as the cathode desorbing the oxide ion conducting in YSZ or SDC. As a result, it was confirmed that the voltage polarity of SC-SOFC could be selectively controlled by making use of the same catalytic electrodes with different sizes, and that the I,V characteristic of the cell improved by using SDC with Pt electrodes with a surface area ratio of 2:1. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

Evaluation of a combined penetrometer for simultaneous measurement of penetration resistance and soil water content

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2004
Yurui Sun
Abstract A combined penetrometer is an appropriate tool to measure the soil cone resistance and the water-content profile. As a relatively new technique, a combined capacitance-penetrometer for the simultaneous measurement of cone index and soil water content was developed at the Department of Agricultural Engineering of Bonn University in 2002. The objective of this study was the evaluation of the effectiveness and applicability of the innovated penetrometer with a focus on three aspects: (1) A capacitance sensor with two electrode configurations was calibrated for silt loam, sandy loam, and sand. The calibration results show that both electrode configurations have sufficient water-content sensitivity, but soil-specific calibrations seem necessary. (2) Under laboratory conditions, the dynamic resolution and response of the capacitance-penetrometer were validated, and its radius of influence was determined. (3) The field measurement results demonstrate that this measurement technique can be used to improve the interpretation quality of soil cone index data. Bewertung eines Penetrometers zur gleichzeitigen Bestimmung von Eindringwiderstand und Bodenfeuchte Für die Ermittlung von Bodenprofilen für den Eindringwiderstand und die Bodenfeuchte erscheint die Kombination aus Penetrometer und Bodenfeuchtesensor als geeignete Lösung. Ein solcher Kombinationssensor wurde im Jahr 2002 am Institut für Landtechnik der Universität Bonn für die simultane Messung des Eindringwiderstandes und der Bodenfeuchte entwickelt. In diesem Beitrag wird die Tauglichkeit und Anwendbarkeit für Feldmessungen in folgenden Schritten dargestellt: (1) Ein kapazitiver Sensor mit zwei Elektrodenkonfigurationen wurde für die drei Bodenarten schluffiger Lehm, sandiger Lehm und Sand kalibiriert. Die Kalibrationsgleichungen zeigen, dass beide Elektrodenanordnungen über ausreichende Empfindlichkeit zur Bodenfeuchtemessung verfügen. Es sind aber bodenartspezifische Kalibrierungen notwendig. (2) Die dynamische Auflösung und das Ansprechverhalten des Feuchtesensors wurden für beide Elektrodenanordnungen untersucht, und die Ausbreitung des dielektrischen Feldes wurde bestimmt. (3) Die Ergebnisse der Messungen im gewachsenen Boden zeigen, dass die Messmethode zur Verbesserung der Interpretation der Konus-Indexwerte herangezogen werden kann. [source]

Modelling electrospinning of nanofibres

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2009
Tomasz A. Kowalewski
Electrospinning is based on so-called bending instability which results in an erratic spiralling motion of the liquid jet as it proceeds towards a collecting electrode, where it is eventually deposited as a mat of micro/nanosized fibres. Most electrospinning models formulated within the slender approximation rely, however, on an inconsistent description of electrostatic interactions which renders them grossly inappropriate whenever the discretization is either too coarse or too fine. The present work aims at proposing a discrete slender model which is numerically consistent (allowing use of arbitrary fine meshes) and remains accurate even for coarse meshes. At the same time, efficient numerical techniques based on hierarchical charge clustering are introduced that drastically decrease computational times. Finally, a versatile boundary value method is implemented to enforce fixed-potential boundary conditions, allowing realistic electrode configurations to be investigated. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]