Corrosion Behavior of Aluminum Wire for Overhead Transmission Lines: Investigation and Analysis

The corrosion behavior of aluminum wire used for overhead transmission lines was studied in four corrosion environments: (1) sodium chloride solution, (2) sodium chloride solution with addition of alumina particles, (3) aluminum chloride solution, (4) aluminum chloride solution with addition of alumina particles. The corrosion tests and polarization measurements revealed that environments 2 and 4 with alumina particles roughened and rapidly corroded the surface of the aluminum wire. It is considered that wet and dry environments of overhead transmission lines change aluminum hydroxide, present as a corrosion product, to alumina (aluminum oxide), which acts as an abrasive and weakens the surface of the aluminum wire. It is also shown that the corrosion of the aluminum wire occurs in an abrasive corrosion environment caused by alumina and corrosion fatigue due to vibration of the overhead wires. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 185(4): 18–24, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22486     

Diffusion control of strongly correlated electrically conductive particles in a liquid medium by applying graded electromagnetic fields

The diffusion phenomenon of strongly correlated electrically conductive (EC) particles by radiating graded electromagnetic fields into a liquid medium is theoretically and experimentally investigated. The state of strongly correlated EC particles is defined in this paper as follows: The energy absorption of electromagnetic fields by EC particles in a liquid medium will induce strong attraction forces between particles, producing thermal, mechanical, and electrical energy from three‐dimensional resistance–capacitance networks composed of the particles. As the strong attraction forces compensate the Brownian motion of the particles, the phenomenon of externally controlled diffusion against natural diffusion is realized by applying a graded electromagnetic field. The controlled diffusion is useful as a method of moving the EC particles toward the target regions. The possible applications of the phenomenon in medical and industrial fields are briefly described. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Behaviour and effect of conducting spiral particles under ACvoltage in a gas insulated electrode system

The behavior and effect of various spiral particles made of conducting wires in an SF₆ insulated electrode system, exposed to AC voltages, are presented. The conducting spiral particle is an idealized form of the helical particles found in practice in the gas-insulated system. The results obtained for particles made of copper and aluminum wires show that the lift-off voltage of the particle is independent of the particle length, whereas the crossing and breakdown voltages are affected by the particle length. The longer the particle, the lower the crossing and the breakdown voltages. The lift-off, crossing, and breakdown voltages decrease when the particle diameter or pitch increases or when the diameter or the density of the wire from which the particle is made decreases, within the pressure ranges examined (1 to 5 bar). The lift-off and crossing voltages for particles with the same overall dimensions but with different pitches are not influenced appreciably by the gas pressure     

Time–frequency analysis of lamb waves caused by partial discharges and free particles in GIS

We investigated the propagation properties of Lamb waves in a GIS tank, using time–frequency analysis to diagnose the insulation performance of GIS. We measured the acoustic signals excited by metallic particles colliding with the tank sheath, and those emitted by partial discharge in the GIS. The wavelet transform was used to decompose the wave data into its time–frequency components. As a result, it was confirmed that Lamb waves with the dispersive property of the velocity are excited and propagate in a spiral path along the tank wall due to the cylindrical structure of the tank. Taking these results into consideration, we propose a new technique for identification of defect locations in GIS based on time–frequency analysis of acoustic signals with the wavelet transform. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(3): 25–32, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10163     

Excess activated sludge reduction by using electromagnets and ferrite particles

Every year, the ratio of the sewarage treatment to population is increasing in Japan. Expansion in sewer networks is leading to the production of excess sludge which is one of the major problems in wastewater treatment plants. There are several approaches to treat the excess activated sludge. A new approach is to reduce excess sludge production by using magneto‐ferrite treatment. The Suzuki Lab of Akita University, Japan, is working on this project. We have succeeded in using magneto‐ferrite treatment in the lab scale to reduce sludge production. Ferrite particles and magnets are used in this method. Ferrite particles are nontoxic and safe for biological systems. They can be easily separated from the sludge by using magnets. However, the movement of the ferrite particles in the sludge is controlled by permanent magnets which can be made more effective by changing to electromagnets. In this paper, we describe an approach to use electromagnets instead of permanent magnets. Electromagnets can be controlled easily with an AC power supply. The results of our experiments have shown a good possibility for reduction of excess sludge. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Detection and clustering of light charged particles via system‐identification techniques

The problem considered in this work is the classification of the particles produced by the collision of a heavy ion beam on a target. Each particle is captured by a detector and results in a signal (which is the impulse response of a dynamic linear system), which is measured by a digital acquisition system. The assumption made herein is that the shape of the impulse‐response contains complete information on the particle, and the classification can be done by pulse‐shape, analysis. In this work, a complete procedure for the particle identification is proposed. The main idea is to use the cascade of a state‐space identification algorithm and a parametric non‐linear map using the model parameters as input regressors. The algorithm has been tested on a large set of impulse‐responses and provides a fully automatic accurate classification of the isotopes. This work focuses on isotopic identification of the most energetic light charged particles (LCP). All the experiments are made with the large detector array CHIMERA (Charge Heavy Ions Mass and Energy Resolving Array). Copyright © 2006 John Wiley & Sons, Ltd.     

Equivalent circuits for small signal performance of spin ½ particles

A quantum system composed of a large number of non‐interacting spin ½ particles, biased by a large constant magnetic field along the z‐axis and excited by a small circularly polarized electromagnetic wave in the xy‐plane is considered. Its small signal reflectance about the equilibrium state resulting from the biasing field and a pumping activity is calculated in the complex frequency plane. It is suggested that the equilibrium state can be locally passive or active depending on the pumping sign and level. Equivalent circuits containing imaginary resistors, i.e. frequency independent reactances, are presented for both passive and active cases. Copyright © 2006 John Wiley & Sons, Ltd.     

Electrical conduction at low fields of composites sparsely filledwith aluminum particles

The dc and ac electrical conduction properties have been investigated in four composites containing hydroxyl-terminated polybutadiene (HTPB) as binder and different proportions of aluminum particles as filler in a temperature range of -60 to +70°C and a frequency range of 40 Hz to 100 kHz. A change in conduction mechanism at a temperature of 4±3°C was displayed explicitly in de measurements. The transition was shown to be due to crystallization of the HTPB upon cooling. dc conduction is explained in terms of ionic hopping in HTPB. Distinct polarization mechanisms, below and above the transition temperature, have been identified as interfacial polarisation and electrode blocking effect, respectively. The change of conduction behaviors at the crystallization temperature, 4±3°C, was not revealed explicitly in ac measurements. However, using the free volume concept to analyze the frequency shift factor a_T, a discontinuity in the fractional free volume curve was displayed. The temperature of the break point, 6.7°C, corresponds to the crystallization temperature of HTPB. The study showed that the crystallization of a polymer is accompanied by an abrupt reduction in free volume, and this structural change affects dc as well as ac conduction behaviors     

Agglomeration of particles by ac corona discharge

Improving the collection efficiency for particles smaller than 1 μm on every precipitator is important. We sought to improve the collection of these particles on an ESP due to particle agglomeration. Particles are charged by ac corona discharge in a precharger and agglomerated by a dc electric field in an agglomerator downstream of the precharger. Diesel exhaust particles were used as particulate matter for the experiments. The distribution of particle size was measured using a particle counter and a scanning electron microscope. By these methods, particles as small as 0.01 μm could be counted. Results showed the agglomeration between particles at ac corona discharge operating mode. The concentration of particles smaller than approximately 0.35 μm decreases, and that of particles larger than approximately 0.35 μm increases in the agglomerator. The agglomeration rate increases with increasing applied voltage, then saturates. These results may be due to the size distribution and to decrease of concentration by agglomeration. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 30–37, 2000     

Glucose-assisted synthesis of metastable pyrite CuSe2 particles through hot injection method

Abstract

CuSe₂, a promising raw material for absorption layer of CuInSe₂-based solar cell, has outstanding electronic and magnetic properties. Here, almost pure pyrite CuSe₂ particles were successfully synthesized by hot injection method using glucose as a substitute for toxic adjuvant. Through XRD, SEM and TEM, samples are carried out microscopic analysis for studying the change of microscopic structure and composition of products obtained from different experiments. The results showed that glucose plays a driving role in the synthesis of CuSe₂ and pure pyrite CuSe₂ can be obtained only when the temperature is suitable.     

Study of corrosion resistance improvement by metallic coating for overhead transmission line conductor

Applying anticorrosion grease and aluminum‐clad steel (AC) wires to ACSR have been adopted as general methods to protect overhead transmission line conductors and/or wires from corrosion. However, in some cases those means have been found to be ineffective on some transmission lines passing through acid atmosphere in the vicinity of a factory exhausting acid smoke. The corrosion caused by acid atmosphere is characterized by a higher speed in its progress as is well known. As means against such acid corrosion, application of high‐purity aluminum, selective removal of intermetallic compound in aluminum, and plastic coating wires have been reported before, and each has both advantages and disadvantages. In a former report, we found that a new type of anticorrosion grease shows an excellent property against acid atmosphere as well as in a salty condition. Here we present a new type of anticorrosion technology of applying high‐corrosion‐resistance aluminum alloy or zinc coatings on each component wire of a conductor that we succeeded in developing through a serial study of anticorrosion methods on overhead transmission lines. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(1): 41–47, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20365     

Observation of the electrorheological effect of siliconeoil/polymer particles suspension

A liquid insulator that suspends small particles is one of the electrorheological fluids (ERF) whose apparent viscosity becomes larger under an electric field because of the formation of particle chains. Since many possible applications of ERF are expected, the development of a more practical ERF is required. We have investigated the ER effect of silicone oil in which small particles are suspended. Silica particles, silica particles coated by conductive polymer film, and polymer particles (microcrystalline cellulose), with a diameter between 5~100 μm, are investigated in order to clarify the difference between suspending materials. To measure the ER effect, a rotational viscometer was constructed. It became clear that the shear stress for cellulose particles is much stronger than that for other particles because of its peculiar particle chain formation due to the particle shape     

Size dependence of THz region dielectric properties for barium titanate fine particles

Barium titanate (BaTiO₃) crystallites with various particle sizes from 22 to 500 nm were prepared by the two-step thermal decomposition method of barium titanyl oxalate. Various characterizations revealed that these particles were impurity-free, defect-free, dense BaTiO₃ particles. The powder dielectric measurement clarified that the dielectric constant of BaTiO₃ particles with a size of around 58 nm exhibited a maximum of over 15,000. To explain this size dependence, the THz region dielectric properties of BaTiO₃ fine particles, especially Slater mode frequency, were measured using the far infrared (FIR) reflection method. As the result, the lowest Slater mode frequency was obtained at 58 nm. This tendency was completely consistent with particle size dependence of the dielectric constant.     

Capture of fine particles on charged moving spheres: a newelectrostatic precipitator

It was verified experimentally that electrostatic cleanup of fly ash dust is possible using the scrubbing action of charged copper particles with diameters 10-100 times the size of the dust particles. Results show that target efficiencies in excess of unity (up to 1.8) are possible as a result of the induced charge on the target particles. Power consumption to the precipitator was confirmed to be very small (~5×10^-4 W). Values of the total collection efficiency of 0.65 (65%) were obtained for a precipitator zone length of 1.2 cm (in the direction of air flow) at air velocities of about 3 cm/s. This value decreased with increasing air flow rate. Collection efficiencies up to 0.99 (99%) are projected with a longer test section of at least 5.3 cm in length for low air velocities of about 3 cm/s, an electric field strength of 10.91 kV/cm, and 114.5 μm copper particles     

Preparation of SrNb2O6 and KSr2Nb5O15 particles with anisometric morphology

Particles with anisometric morphology were found to play an important role in the fabrication of textured ceramics. SrNb₂O₆ particles with tetragonal tungsten bronze (TTB) structure were synthesized by solid-state reaction (SSR) method and molten salt synthesis (MSS) technique respectively. Morphology and the growth mechanism of SrNb₂O₆ particles were investigated. It was found that the growth of SrNb₂O₆ particles is dominated by diffusion mechanism. SrNb₂O₆ particles synthesized by MSS method exhibited higher aspect ratio relative to those prepared by SSR method. Furthermore, anisometric KSr₂Nb₅O₁₅ particles, which exhibited higher aspect ratio than SrNb₂O₆ particles, were synthesized by MSS method. The length of KSr₂Nb₅O₁₅ particles was longer than that of SrNb₂O₆ particles.     

Control Method for Harmonic Voltage Injection to Achieve Noise Reduction in Position‐Sensorless Control of Permanent‐Magnet Synchronous Motors at Low Speeds

In this study, we examine the relationship between harmonic voltage injection, acoustic noise, and position estimation performance in a PMSM when a position‐sensorless control method involving harmonic voltage injection is used at low speeds. Further, we propose a novel control method for voltage injection; this method can be used to reduce acoustic noise in the motor. The proposed control method is verified by performing numerical simulations and carrying out experiments using a four‐pole, 2‐kW, 2100‐rpm IPMSM (interior permanent‐magnet synchronous motor). © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(3): 49–56, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21246     

Selective adsorption and separation of adenine by molecularly imprinted polymethacrylic acid on surface of silica particles

ABSTRACT

Adenine molecular imprinted polymethacrylic acid (PMAA) was in situ prepared on the surface of silica (SiO₂) microspheres, constituting a thin and rough molecular imprinted polymer (MIP) layer as characterized by SEM, TEM and FT-IR. Dynamic method and competitive adsorption experiments were used to investigate the adsorption kinetics, adsorption isotherms, selective recognition and adsorption reproducibility of MIP-PMAA/SiO₂ particles toward adenine. The results showed that the obtained particles have strong selective affinity, specific recognition and excellent reusability for adenine. MIP-PMAA/SiO₂ particles were further used as stationary phase for high performance liquid chromatography (HPLC) and separation of adenine from other nucleic bases was achieved successfully.     

Pilot-plant testing of a novel electrostatic collector for submicrometer particles

A novel electrostatic collector CAROLA (Corona Aerosol Abscheider) for gas cleaning from submicrometer particles is described. The CAROLA concept is based on particle charging by corona discharge and subsequent particle removal in the grounded part of the collector. CAROLA collectors for fine oil mists and for fly ash were tested. The influence of the operation conditions on corona discharge was studied. It is shown that the CAROLA electrostatic collectors have high fractional removal efficiencies (>98% for particles >1 /spl mu/m and 95%-98% for particles with sizes 0.3-1 /spl mu/m), low operating voltages (10-20 kV), and low pressure drop (<200 Pa). The collection of charged particles without external electric field and the compact design provide a cost-effective solution for the removal of submicrometer particles from industrial off gases.     

Dielectrophoretic manipulation of particles

We have demonstrated that, in general, the dielectrophoretic (DEP) force experienced by a particle has two components. The first depends upon inhomogeneities in the applied electrical field strength and upon the in-phase part of the resultant dipole moment induced in the particle and can be identified with the conventional dielectrophoretic (cDEP) force. The second relates to nonuniformities in the phase distribution of the applied field and to the out-of-phase part of the induced dipole moment. A nonuniform phase distribution corresponds to a field that travels through space. This second force component gives rise to traveling-wave dielectrophoresis (twDEP). In this paper, we describe several electrode configurations designed to produce electric fields capable of inducing cDEP and twDEP forces for the purpose of manipulating particles. Using DS19 Friend murine erythroleukemia cells as test particles having well-characterized dielectric properties, we investigated the electrokinetic behaviors for these electrodes as a function of frequency and electrode excitation mode. Several characteristic cell electrokinetic behaviors were identified, including trapping, linear motion, levitation, and circulation of the cells, depending on the excitation characteristics of the electrodes and the cell dielectric properties. We describe these findings and rationalize them in terms of the field distributions produced by the electrodes, the particle dielectric properties, and generalized dielectrophoresis theory. The biotechnological applications of dielectrophoretic manipulation are then discussed     

Motion of conducting particles causing inadvertent outages in GIS

Inadvertent failure of a HV gas-insulated system (GIS) is traced to a seemingly innocuous mechanism in particle-induced breakdown. Impending dangers from inconspicuous conducting particles in a large physical system are quite intriguing. The dynamic behavior of the particle due to electric field/particle/fluid medium interaction is a complex phenomenon. To understand this interaction a credible database has been generated for the field-induced motion of the particles on a physical prototype model. Induced surface charge acquired by the particle is calculated based on the proposed model (field calculations) and by considering it to be a prolate ellipsoid. Methods for deactivating potentially dynamic particles using dielectric coated active parts and grounded enclosures, and a novel technique called reverse polarity charging have been suggested. Performance of GIS in the presence of metallic particles has been studied with bare electrodes and with dielectric coatings of different conductivities with a view to obtain an optimal value of the conductivity