bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electric field of surface discharge inception by electrification charge
Authors: Tashiro Shinichi , Endo Masao 
Published: July 2003

AbstractIt is well known that a surface discharge is significantly affected by the electrification charge on the surface of an insulator. However, only limited information is available concerning the electric field strength of a surface discharge produced by the charge itself. This paper describes the relationship between the surface discharge inception field caused by the charge itself and the pressure. After electrification of the surface of a film covering a plane electrode by a corona discharge produced with a needle electrode, this electrode system was placed in a vacuum chamber and the pressure was lowered. A weak discharge momentarily occurred at a critical pressure around the center of the electrification charge. We obtained the relation between the maximum field strength and the critical pressure in the range of about 50 to 1000 hPa. It should be emphasized that the inception electric field was 6 to 8 kV/mm at atmospheric pressure and 0.5 kV/mm at 50 hPa. Finally, these results are discussed, comparing the flashover voltage of the uniform field and the electric field of discharge inception obtained by experiments at various altitudes in lightning clouds. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(2): 1–9, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10192
Trial design of a 6.6‐kV magnetic shielding type of superconducting fault current limiter and performance analysis based on a finite element method
Authors: Kado Hiroyuki , Ichikawa Michiharu , Ueda Hiroshi , Ishiyama Atsushi 
Published: July 2003

AbstractSuperconducting fault current limiter (SCFCL) is expected to be a first application of high‐TC superconductors to electric power systems. We have been developing a magnetic shielding type of SCFCL. In this paper, we propose a design method for the magnetic shield SCFCL. The method is based on a newly developed computer program which can evaluate the dynamic thermal and electromagnetic behaviors of high‐TC superconducting cylinder in fault current limiter operation. As an example, the trial design of a model system, which is 6.6 kV (rms) in rated voltage, 400 A(rms) in rated current, and 12.5 kA(rms) in maximum prospective short‐circuit current, is shown. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(2): 50–57, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10197
Load‐following control for dispersed generators using a PI controller
Authors: Senjyu Tomonobu , Takara Hitoshi , Uezato Katsumi , Funabashi Toshihisa , Ito Takamitsu 
Published: July 2003

AbstractRecently, there has been growing interest in utilizing dispersed generation systems, which are grouped into micro turbine systems, co‐generation systems, and so on, as a substitute for fuel oil energy and a technology to prevent global warming. Since start‐up time of dispersed generation systems is short, it is possible to operate systems to supply load power corresponding to a demand. Moreover, PPSs (Power Producers and Suppliers) can participate in a power retail sales company, since deregulation of electric utilities was instituted in March 2000. However, PPSs have to keep instantaneous generating power commissioning rule, to maintain supply‐and‐demand balance between customer and supplier. Therefore, in this paper, we examine instantaneous generating power commissioning for dispersed generators where start‐up time is short and it is possible to operate systems to supply a power load corresponding to a demand. We adopt a PI controller as a controller. The system is composed of double control loop in inner loop and in outer loop. In inner loop electric power is controlled and in outer loop electric energy is controlled. The controller parameters are designed using the pole‐placement technique. The effectiveness of the proposed control system is confirmed by simulations. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(2): 58–66, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10200
A novel method for active filter current regulation using deadbeat control
Authors: Hamasaki Shin‐Ichi , Kawamura Atsuo 
Published: July 2003

AbstractThe shunt‐type active filter (AF), which is widely used due to its protection capability, is installed in parallel to the load. It is considered as an ideal current source and it compensates the harmonic current of the load. However, the AF is practically realized by a current regulator using a voltage source‐type inverter, and it is very difficult to realize the AF current as an ideal current source, especially when it is controlled by digital equipment.A new control scheme for a line current detection AF is proposed to improve the current regulation capability based on digital deadbeat control. The current control scheme is achieved by controlling the intermediate voltage of the inverter output filter so that the AF output current is regulated, using the dead‐beat control law for the calculation of the pulse width of the PWM inverter. In the proposed scheme, the current regulation performance is much better than in the conventional one.The control method, mathematical analysis, simulation results, and experimental results are presented in this paper. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(2): 67–77, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10201
Recent Updates of Chemically Modified Electrodes in Analytical Chemistry
Authors: Zen Jyh‐Myng , Senthil Kumar Annamalai , Tsai Dong‐Mung 
Published: July 2003

AbstractThis review article updates recent developments in chemically modified electrodes (CMEs) towards analytical applications for the year of 2000–2002 with 179 references. The broad topics are subdivided into four main categories: i) physisorption/chemisorption, ii) covalently linked, iii) homogenous (uniform) multilayer and iv) heterogeneous (non‐uniform) multilayer CMEs. The criteria for the preparation of CMEs in elecrocatalytic systems are clearly described in Section 1. Some of the encouraging results related to Au‐nanoparticles for DNA detection and new ceramic carbon, carbon nanotubes, copper‐plated screen‐printed and Nafion/lead ruthenate pyrochlore CMEs for catalytic application were especially discussed in this review.
Biosensors Based on Aligned Carbon Nanotubes Coated with Inherently Conducting Polymers
Authors: Gao Mei , Dai Liming , Wallace Gordon G. 
Published: July 2003

AbstractThe use of multiwalled aligned carbon nanotubes provides a novel electrode platform for inherently conducting polymer based biosensors. The example used here to highlight the usefulness of such a platform is the polypyrrole based glucose oxidase system for detection of glucose. The use of these three dimensional electrodes offers advantages in that large accessible enzyme loadings can be obtained within an ultrathin layer. It has also been found that the detection of H2O2 at these new electrode structures containing iron loaded nanotube tips can be achieved at low anodic potentials. The result is a sensitive and selective glucose sensor.
New Strategy for Dehydrogenase Amperometric Biosensors Using Surfactant to Enhance the Sensitivity of Diaphorase/Ferrocene Modified Carbon Paste Electrodes for Electrocatalytic Oxidation of NADH
Authors: Ramírez‐Molina César , Boujtita Mohammed , El Murr Nabil 
Published: July 2003

AbstractA carbon paste electrode (CPE) modified with diaphorase (DAP) and ferrocene (FcH) has been developed for determination of NADH at low working potential. The sensitivity and operational stability, towards the detection of the reduced form of the nicotinamide adenine dinucleotide (NADH) in flow injection analysis (FIA), were greatly improved (5 times) upon adding Tween 20 into the electrode matrix. The magnitude of the amperometric signal was dependent on DAP, FcH and surfactant loading, into the modified carbon paste electrode. A rapid and repeatable response was observed to the variation of NADH concentration in the vicinity of the electrode surface. Such advantages of the DAP/FcH/Tween 20 modified carbon paste were successfully used in the construction of L‐lactate dehydrogenase modified electrodes. The use of this new approach can be generalized to other dehydrogenases and represents a decisive step for a versatile preparation method of amperometric biosensors.
The Voltammetric Behavior of Superoxide Dismutase/Catalase Mimics
Authors: O'Hare Danny , Fucassi Flavia , Cragg Peter J. , Green Michael H. L. 
Published: July 2003

AbstractThe voltammetric behavior of the superoxide dismutase/catalase mimics [(N,N′‐bis(salicylidene)ethylenediamine)Mn(III)]Cl (or salenMn(III) chloride) 1 and [(N,N′‐bis(3‐methoxysalicylidene)ethylenediamine)Mn(III)]Cl (or 3,3′‐methoxysalenMn(III) chloride) 2 in acetonitrile is described. Both compounds show quasi‐reversible one‐electron reductions to the Mn(II) compound. Electroanalytical techniques are used to follow the reaction between superoxide and 1 and 2 and it is shown that it is the reduced Mn(II) compounds which scavenge superoxide. It is also shown that both compounds electrocatalytically generate superoxide in the presence of dissolved dioxygen. The rate constant for this reaction was determined for both compounds using microelectrode steady state voltammetry. A general reaction scheme for interactions between these compounds and both dissolved dioxygen and superoxide is proposed.
A Siloxane Homopolymer with Interacting Ferrocenes as a New Material for the Preparation of Sensors Based on the Detection of Hydrogen Peroxide
Authors: Garcí Armada M. Pilar , Losada José , Cuadrado Isabel , Alonso Beatriz , González Blanca , Casado Carmen M. 
Published: July 2003

AbstractThe electrochemical characterization of a hydrogen peroxide sensor based on a ferrocene‐containing polymer electrochemically deposited onto a platinum electrode is described. The redox polymer consists of a siloxane‐based homopolymer, with pendant electronically communicated ferrocenyl moieties. The electrodes were used as the transducer for glucose and lactate‐sensing enzyme sensors. Amperometric biosensors were prepared by immobilization of glucose oxidase (Gox) or lactate oxidase (Lox) onto these modified electrodes. The steady‐state amperometric response of the sensors is investigated as a function of the applied potential and substrate concentration. Interferences, sensitivity and stability of the sensors were also studied.
TTF‐TCNQ Functionalized Ormosil Based Electrocatalytic Biosensor: A comparative study on Bioelectrocatalysis
Authors: Pandey P. C. , Upadhyay S. , Sharma S. 
Published: July 2003

AbstractA novel electrocatalytic biosensor for glucose is reported that incorporate encapsulation of tetrathifulvalene‐tetracyanoquinodimethane (TTF‐TCNQ) functionalized organically modified sol gel glass (ormosil). The new ormosil is made using palladium‐linked glycidoxypropyltrimethoxysilane precursor, trimethoxysilane, HCl and TTF‐TCNQ powder at 25 °C. The ormosil is converted into fine powder and incorporated within graphite paste electrode along with glucose oxidase. The bioelectrochemistry of GOD and TTF‐TCNQ functionalized ormosil is examined based on cyclic voltammetry and amperometric measurements. A large electrocatalytic current to the order of 8000 μA/cm2 is recorded on the addition of 300 mM glucose. Typical responses of new biosensor are reported. The sensitivity of glucose analysis is found relatively much better as compared to earlier reported glucose biosensors. The role of palladium and TTF‐TCNQ introduction within ormosil and its advantages on bioelectrocatalysis are discussed.
Determination of Melatonin Hormone in Bulk Form, Tablets and Human Serum by Square‐Wave Cathodic Adsorptive Stripping Voltammetry
Authors: Beltagi A. M. , Khashaba P. Y. , Ghoneim M. M. 
Published: July 2003

AbstractMelatonin hormone plays an important role in many distinct physiological functions. A fully validated, sensitive and reproducible square‐wave cathodic adsorptive stripping voltammetric procedure was described for determination of melatonin in bulk form, tablets and human serum. The procedure was based on the reduction of the adsorptive hormone onto a hanging mercury drop electrode. Reduction behavior of melatonin was studied in both Britton‐Robinson (pH 2–11) and acetate (4.5–5.5) buffers. Acetate buffer of pH 5.0 was found reasonable as a supporting electrolyte for assay of the drug. The square‐wave cathodic adsorptive stripping voltammogram of melatonin showed a single well‐defined peak at −1.45 V (vs. Ag/AgCl/KCls) using an accumulation potential of −0.65 V. This peak may be attributed to the reduction of CO double bond of the amide functional group of the reactant molecule. A mean recovery for 1×10−8 M melatonin in bulk form followed 30 s accumulation of 98.87%±0.78 and a detection limit of 3.13×10−10 M were achieved. The proposed procedure was successfully applied for the determination of the drug in tablets and human serum with mean recoveries of 97.68%±0.57 and 101.67%±0.85, respectively. A detection limit of 8.80×10−10 M was achieved for the determination of the drug in human serum. Results of the proposed method were comparable and coincided with those obtained by reported method. Vitamin B6 and common excipients, which are co‐formulated with melatonin, did not interfere. Also the effect of some interfering compounds such as serotonin, tryptophan and 5‐hydroxytryptophan on the determination of melatonin in human serum was studied, and all have no significant effect on the assay recovery.
The Electrocatalytic Oxidation of Thymine at α‐Cyclodextrin Incorporated Carbon Nanotube‐Coated Electrode
Authors: Wang Zonghua , Wang Yiming , Luo Guoan 
Published: July 2003

AbstractElectrocatalytic oxidation of thymine at α‐cyclodextrin (α‐CD) incorporated carbon nanotube‐coated electrode (CNT/CE) was thoroughly studied in alkaline media. CNT showed an electrocatalytic effect on the oxidation of thymine, formation of a supramolecular inclusion complex between α‐CD and thymine at CNT/CE further enhanced the sensitivity to thymine. The electrocatalytic behavior was further developed as a sensitive detection scheme for thymine by differential pulse voltammetry. A linear calibration over the concentration range from 2.5×10−5 to 1.8×10−3 mol/L in pH 10.8 NaHCO3‐Na2CO3 buffer solution was obtained with a detection limit of 5×10−6 mol/L.
Evaluation of the Conductivity of the Polypyrrole Film via Its CC Bonds Stretching on Surface‐Enhanced Raman Spectrum
Authors: Liu Yu‐Chuan 
Published: July 2003

AbstractIn this study, the conductivities of various polypyrrole (PPy) films were evaluated via the corresponding surface‐enhanced Raman scattering (SERS) spectrum and X‐ray photoelectron spectroscopy (XPS). The results indicate that the peak position of CC bonds stretching of PPy obtained from the SERS spectrum shows more exactly both qualitatively and quantitatively representing the conductivity of PPy than the N+/N ratio or the doping level obtained from the XPS analysis does. Namely the peak position of CC bonds stretching of PPy monotone decreases to a lower frequency side with the increase of the conductivity of PPy. Furthermore, a satisfactory correlated equation between them was obtained. On the contrary, neither the N+/N ratio nor the doping level can be qualitatively reflective on the corresponding conductivity of PPy.
Polyelectrolyte Multilayer Films Containing Ferrocene: Effects of Polyelectrolyte Type and Ferrocene Contents in the Film on the Redox Properties
Authors: Liu Aihua , Kashiwagi Yoshitomo , Anzai Jun‐ichi 
Published: July 2003

AbstractElectrochemical properties of Fc‐PEM films have been studied by changing the chemical structure of the polymer chains and the content of Fc moiety in the film systematically. We have prepared a series of PEM films by a layer‐by‐layer deposition of polycations, Fc‐modified poly(allylamine) (Fc‐PAA) and poly(ethyleneimine) (Fc‐PEI), and polyanionic poly(vinyl sulfate) (PVS) on the surface of a gold electrode. The redox properties of the Fc‐PAA/PVS and Fc‐PEI/PVS films depended significantly on the content of Fc moiety in the polymer chains and on the polymer type. Fc‐ PAA and Fc‐PEI polymer chains can penetrate 3 or 4 PAA/PVS bilayers inserted between the redox polymers and electrode. The Fc‐PAA film‐modified electrode can be used for electrocatalytic oxidation of ascorbic acid.
Flow reversal over a natural pool–riffle sequence: a computational study
Authors: Cao Zhixian , Carling Paul , Oakey Rob 
Published: July 2003

AbstractA computational study is presented on the hydraulics of a natural pool–rifﬂe sequence composed of mixed cobbles, pebbles and sand in the River Lune, northern England. A depth‐averaged two‐dimensional numerical model is employed, calibrated with observed data at the ﬁeld site. From the computational outputs, the occurrence of longitudinally double peak zones of bed shear stress and velocity is found. In particular, at low discharge there exists a primary peak zone of bed shear stress and velocity at the rifﬂe tail in line with the local maximum energy slope, in addition to a secondary peak at the pool head. As discharge increases, the primary peak at the rifﬂe tail at low ﬂow moves toward the upstream side of the rifﬂe along with the maximum energy slope, showing progressive equalization to the surrounding hydraulic proﬁles. Concurrently, the secondary peak, due to channel constriction, appears to stand at the pool head, with its value increasing with discharge and approaching or exceeding the primary peak over the rifﬂe. The existence of ﬂow reversal is demonstrated for this speciﬁc case, which is attributable to channel constriction at the pool head. A dynamic equilibrium model is presented to reconstruct the pool–rifﬂe morphology. A series of numerical modelling exercises demonstrates that the pool–rifﬂe morphology is more likely produced by shallow ﬂows concentrated with coarse sediments than deep ﬂows laden with low concentrations of ﬁne sediments. It is concluded that channel constriction can, but may not necessarily, lead to competence reversal, depending on channel geometry, ﬂow discharge and sediment properties. Copyright © 2003 John Wiley & Sons, Ltd.
An optical tachometer for short‐path measurement of flow speeds in shallow overland flows: improved alternative to dye timing
Authors: Dunkerley David L. 
Published: July 2003

AbstractTracers, such as ﬂuorescein dye, are widely employed to measure overland ﬂow speeds by time‐of‐travel along measured ﬂow paths. Among several disadvantages of this method are the involvement of human reaction time when using stop‐watches, and the relatively long travel path that is consequently needed for reliable timing. Long ﬂow paths mean that local variability along the ﬂow path cannot be detected.This paper describes a new optical tachometer that overcomes these limitations, as well as offering other advantages. It is based on the use of a small ﬂoating reﬂector target that is carried on the surface tension ﬁlm, and which passes between two reﬂective sensors mounted above the ﬂow. The new device allows virtual ‘spot’ measurements of surface ﬂow speed over a path as short as 1 cm, and eliminates the inﬂuence of human reaction time. The new device is battery powered and portable, and provides an improved alternative to dye timing in many ﬁeld and laboratory applications. Its use will allow the collection of more reﬁned data than have hitherto been easily achievable. Copyright © 2003 John Wiley & Sons, Ltd.
Hydrologic and geomorphic effects of temporary ice‐dammed lake formation during jökulhlaups
Authors: Roberts Matthew J. , Tweed Fiona S. , Russell Andrew J. , Knudsen Óskar , Harris Timothy D. 
Published: July 2003

AbstractGlacial outburst ﬂoods (jökulhlaups) occur frequently in glaciated environments, and the resultant ﬂooding causes geomorphic change and, in some instances, damage to local infrastructure. During some jökulhlaups, ﬂoodwater is stored temporarily in ice‐marginal locations. In July 1999, a linearly rising jökulhlaup burst from Sólheimajökull, Iceland. During this remarkable event, subglacial ﬂoodwater pooled transiently in two relict ice‐dammed lake basins, before draining suddenly back into Sólheimajökull. The signiﬁcance of such rapid formation and attendant drainage of temporary ice‐dammed lakes during jökulhlaups has not been addressed. Consequently, this paper: (i) assesses the hydrologic and geomorphic effects of temporary ice‐dammed lake formation caused by lake‐basin ‘retro‐ﬁlling’; and (ii) discusses the impact and signiﬁcance of transient retro‐ﬁlling under jökulhlaup conditions. Pre‐ and post‐ﬂood ﬁeldwork at Sólheimajökull enabled the impact and signiﬁcance of lake‐basin retro‐ﬁlling to be assessed. Field evidence demonstrates that the July 1999 jökulhlaup had an unusually rapid rise to peak discharge, resulting in subglacial ﬂoodwater being purged to ice‐marginal locations. The propensity for temporary retro‐ﬁlling was controlled by rapid expulsion of ﬂoodwater from Sólheimajökull, coincident with locations suitable for ﬂoodwater storage. Floodwater inundated both ice‐marginal lake basins, permitting signiﬁcant volumes of sediment deposition. Coarse‐grained deltas prograding from the ice margin and boulders perched on scoured bedrock provide geomorphic records of sudden retro‐ﬁlling. The depositional characteristics of lake‐basin deposits at Sólheimajökull are similar to jökulhlaup sediments documented in proglacial settings elsewhere; however, their depositional setting and association with ice‐marginal landforms is distinctive. Findings suggest that temporary ice‐dammed lake formation and drainage has the capacity to alter the shape of the ﬂood hydrograph, especially if drainage of a temporary lake is superimposed on the original jökulhlaup. Deposits associated with lake‐basin retro‐ﬁlling have a long‐term preservation potential that could help to identify temporary ice‐dammed lake formation in modern and ancient glacial environments. Copyright © 2003 John Wiley & Sons, Ltd.
Spatial and temporal factors controlling short‐term sedimentation in a salt and freshwater tidal marsh, Scheldt estuary, Belgium, SW Netherlands
Authors: Temmerman S. , Govers G. , Wartel S. , Meire P. 
Published: July 2003

AbstractDuring a one‐year period temporal and spatial variations in suspended sediment concentration (SSC) and deposition were studied on a salt and freshwater tidal marsh in the Scheldt estuary (Belgium, SW Netherlands) using automatic water sampling stations and sediment traps. Temporal variations were found to be controlled by tidal inundation. The initial SSC, measured above the marsh surface at the beginning of inundation events, increases linearly with inundation height at high tide. In accordance with this an exponential relationship is observed between inundation time and sedimentation rates, measured over 25 spring–neap cycles. In addition both SSC and sedimentation rates are higher during winter than during summer for the same inundation height or time. Although spatial differences in vegetation characteristics are large between and within the studied salt and freshwater marsh, they do not affect the spatial sedimentation pattern. Sedimentation rates however strongly decrease with increasing (1) surface elevation, (2) distance from the nearest creek or marsh edge and (3) distance from the marsh edge measured along the nearest creek. Based on these three morphometric parameters, the spatio‐temporal sedimentation pattern can be modelled very well using a single multiple regression model for both the salt and freshwater marsh. A method is presented to compute two‐dimensional sedimentation patterns, based on spatial implementation of this regression model. Copyright © 2003 John Wiley & Sons, Ltd.