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Article
Publication date: 30 October 2018

Satyabrata Dash, Sukanta Dey, Deepak Joshi and Gaurav Trivedi

The purpose of this paper is to demonstrate the application of river formation dynamics to size the widths of power distribution network for very large-scale integration…

Abstract

Purpose

The purpose of this paper is to demonstrate the application of river formation dynamics to size the widths of power distribution network for very large-scale integration designs so that the wire area required by power rails is minimized. The area minimization problem is transformed into a single objective optimization problem subject to various design constraints, such as IR drop and electromigration constraints.

Design/methodology/approach

The minimization process is carried out using river formation dynamics heuristic. The random probabilistic search strategy of river formation dynamics heuristic is used to advance through stringent design requirements to minimize the wire area of an over-designed power distribution network.

Findings

A number of experiments are performed on several power distribution benchmarks to demonstrate the effectiveness of river formation dynamics heuristic. It is observed that the river formation dynamics heuristic outperforms other standard optimization techniques in most cases, and a power distribution network having 16 million nodes is successfully designed for optimal wire area using river formation dynamics.

Originality/value

Although many research works are presented in the literature to minimize wire area of power distribution network, these research works convey little idea on optimizing very large-scale power distribution networks (i.e. networks having more than four million nodes) using an automated environment. The originality in this research is the illustration of an automated environment equipped with an efficient optimization technique based on random probabilistic movement of water drops in solving very large-scale power distribution networks without sacrificing accuracy and additional computational cost. Based on the computation of river formation dynamics, the knowledge of minimum area bounded by optimum IR drop value can be of significant advantage in reduction of routable space and in system performance improvement.

Details

Journal of Systems and Information Technology, vol. 20 no. 4
Type: Research Article
ISSN: 1328-7265

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Article
Publication date: 2 February 2015

Ling Chunxian Zou and Chris Hunt

This paper aims to describe the development of an approach that uses a flexible substrate to investigate the mechanism of conductive anodic filament (CAF) growth and…

Abstract

Purpose

This paper aims to describe the development of an approach that uses a flexible substrate to investigate the mechanism of conductive anodic filament (CAF) growth and effect of different material and manufacturing variables.

Design/methodology/approach

A new approach using a simulated test vehicle (STV) has been developed to study the CAF phenomena. The STV can be easily built under controlled conditions in the laboratory using different glass fibres and resin powder to investigate the effect of different variables separately on CAF. The advantage of the STV is that CAF can be formed in relatively short period in a controlled way, and CAF growth can be easily identified using a back-lighting under a microscope due to the thin flex material used as the test sample.

Findings

STV has been used to investigate a number of effects on CAF formation: different glass fibres, reflow process, acid contamination in drilled holes, desmear process and glass bundle size. The results demonstrate that for finished fibres acid contamination (plating solution) at the electrode was necessary for CAF formation. However, for unfinished glass fibres (loom state and heat cleaned) CAF can be formed without acid contamination. The reflow process significantly increases CAF formation. Running an aggressive desmear process and using large glass fibre bundle also increased CAF formation.

Originality/value

This new approach will be of benefit for printed circuit board (PCB) supplier to evaluate CAF performance on different resin systems and glass fibres to provide high CAF resistance quality PCBs. The test period (168 hours) would be much shorter than the traditional CAF testing (1,000 hours).

Details

Soldering & Surface Mount Technology, vol. 27 no. 1
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 February 2001

M. Deyá, V.F. Vetere, R. Romagnoli and B. del Amo

The efficiency of two anticorrosive pigments containing aluminium polyphosphate was studied. Pigments were analysed by current analytical techniques and characterised by…

Abstract

The efficiency of two anticorrosive pigments containing aluminium polyphosphate was studied. Pigments were analysed by current analytical techniques and characterised by FT‐IR spectrometry. The anticorrosive properties of the selected pigments were evaluated following the electrochemical behaviour of a steel electrode in pigments suspensions. In a second stage, solvent‐borne paints with 30 and 10% v/v of the pigment and PVC/CPVC (pigment volume concentration/critical pigment volume concentration) ratio 0.8 were formulated. Three resins were chosen as film forming materials: an alkyd, an epoxy and a vinyl. The performance of the resulting anticorrosive paints was assessed by accelerated (salt spray cabinet and humidity chamber) and electrochemical tests (corrosion potential, ionic resistance and polarisation resistance). The anticorrosive performance of the tested paints was closely related with pigment composition. The nature of the resin was also of importance; in this sense, epoxy paints showed the best anticorrosive performance. Good correlation has been obtained between accelerated and electrochemical tests.

Details

Pigment & Resin Technology, vol. 30 no. 1
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 23 March 2010

G.H. Sedahmed, H.A. Farag, M.A. Hassan and I. Hassan

The purpose of this paper is to study the effect of the relative velocity between ship hull and seawater on the rate of zinc consumption and degree of cathodic protection…

Abstract

Purpose

The purpose of this paper is to study the effect of the relative velocity between ship hull and seawater on the rate of zinc consumption and degree of cathodic protection during sacrificial cathodic protection of steel hulls using zinc anodes.

Design/methodology/approach

The rate of zinc consumption under different relative velocities was determined by the loss in weight technique while the degree of cathodic protection of the ship hull at different distances from the anode was determined by measuring the cathode potential of the hull cathode against a silver/silver chloride reference electrode.

Findings

Within the present range of conditions, the rate of zinc consumption (R) was found to increase with increasing the relative velocity according to equations: R=3.9×10−4 Re0.0126; for Re<3,500, and R=7.36×10−6 Re0.5; for Re>3,500, where Re is the Reynolds number. The degree of cathodic protection represented by the hull (cathode) potential at a given distance from the anode was found to decrease slightly with increasing the relative velocity.

Originality/value

The present results would make it possible for the designer of sacrificial cathodic protection systems to assess the amount of zinc required to protect the ship hull under certain operating conditions more accurately than the situation where the effect of the relative velocity was not considered.

Details

Anti-Corrosion Methods and Materials, vol. 57 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 4 November 2013

Esmaeel Naderi, Mohammad Hadi Moayed and Mohsen Rahman

In this investigation, attempts were made to distinguish critical coating faults in order of repair priority in DCVG+CIPS survey data by new proposed equation for…

Abstract

Purpose

In this investigation, attempts were made to distinguish critical coating faults in order of repair priority in DCVG+CIPS survey data by new proposed equation for calculating IR drop. The paper aims to discuss these issues.

Design/methodology/approach

DCVG+CIPS, XRD, EDS.

Findings

A new empirical equation was developed which is able to predict the importance more precisely. Besides, the studies proved the corrosion products were mainly hematite and goethite, and the presence of Cl anions was not noticed. As a result, the corrosion attack had a form of non-uniform localized corrosion.

Originality/value

The values were gathered by DCVG+CIPS method of survey.

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 16 August 2019

Qian Hu, Saiwen Lu, Jing Liu and Feng Huang

The purpose of this paper is to clarify the influence of bicarbonate, chloride and outer electrode potential on crevice corrosion occurrence and development of X70 steel.

Abstract

Purpose

The purpose of this paper is to clarify the influence of bicarbonate, chloride and outer electrode potential on crevice corrosion occurrence and development of X70 steel.

Design/methodology/approach

The crevice corrosion behavior in NaHCO3 and NaCl solutions was investigated through modeling and experiments. The electrode potential and current density distribution were simulated, and the acidification of crevice solution was monitored in situ.

Findings

The bicarbonate concentration and outer electrode potential remarkably influenced the occurrence of crevice corrosion. The former changes the passivation curves, and the latter alters the initial potential. Moreover, chloride concentration exerted minimal influence. The location of acidification and pitting occurrences depended on the potential difference between the outer electrode and electrode at the active dissolution current peak.

Originality/value

This study provides a better understanding of the crevice corrosion behavior and mechanism under natural conditions.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 2 January 2018

L.M. Quej-Ake and A. Contreras

The purpose of this work is to study the corrosion rate of X52 pipeline steel exposed to three types of soils collected in Campeche State in México. The electrochemical…

Abstract

Purpose

The purpose of this work is to study the corrosion rate of X52 pipeline steel exposed to three types of soils collected in Campeche State in México. The electrochemical evaluation for X52 steel exposed to soils ranging from saturated soil until dry conditions was carried out for a period of 21 days. Owing to its versatility to study the steel corrosion process exposed to different types of soils, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and cyclic voltammetry tests were performed. Additionally, optical and electronic microscopy observations of the steel surface were carried out.

Design/methodology/approach

Electrochemical cell arrangement was described elsewhere (Quej-Ake et al., 2014). Owing to soil being an electrolytic system with high resistivity and impedance, all electrodes were placed as close as possible, and iR-drop compensation was taken into account using two rods of graphite as an auxiliary electrode. In addition, the conductivity of the soil (Rs) obtained from EIS was used to correct the potential of the working electrode according to iR-drop, and an analysis of ohmic drop from the polarization curves was carried out.

Findings

Saturated conditions of the three soils were initially considered as the most corrosive conditions for X52 steel surface. Finally, 21 days of immersion time was taken into account as the more drastic condition. So, according to results, X52 steel exposed to beach sand was more susceptible to the corrosion process (0.092 mm/year). iR corrected was negligible at low over-potentials region in saturated soils, which is inside the linear region of Tafel or the activation region. In addition, high cathodic peak potential value obtained from cyclic voltammetry for X52 steel exposed to saturated soil may be attributed to hydrogen evolution reaction and neutral pH.

Research limitations/implications

The paper has implications for research. It bridges the gap between theory and practice.

Originality/value

Cyclic voltammetry is a really important tool for the electrochemical analysis of the pipeline steel surface exposed to saturated soils, but is not adequate for analysis of steel exposed to dried soils. In addition, the physicochemical results show that fissures, voids and extra-oxygen presence could also affect the electrochemical responses obtained for X52 steel exposed to soils.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 21 June 2021

Mohammed I. Abdulsalam and Francisco Presuel-Moreno

The purpose of this paper is to study the susceptibility of these three commonly used corrosion resistance fasteners in seawater. For a more practical scenario, a local…

Abstract

Purpose

The purpose of this paper is to study the susceptibility of these three commonly used corrosion resistance fasteners in seawater. For a more practical scenario, a local Atlantic coastal seawater as received was used.

Design/methodology/approach

Carbon fiber reinforced polymer (CFRP) was fabricated with T700 carbon fiber (Toray Inc.) and VE8084 vinyl ester resin (Ashland) to make a unidirectional composite panel of thickness 1.8 mm. A conductive paint was applied to one of the sample edges that was perpendicular to the fiber direction, providing an electrical contact with carbon fibers to connect a copper wire. This external electric connection was used for potential measurements of both the open circuit potential (OCP) of the CFRP sample, and the mixed potential of the fastened set: consisting of the CFRP and the metallic fastener fastened to it. Three common fastener alloys were selected: 316SS, Monel and Titanium. For this purpose, a high impedance voltmeter was used in conjunction with a saturated calomel reference electrode. Measurements were taken daily. For longer time measurements, a four-channel high impedance analog data logger was used with 30 min sampling rate.

Findings

For both 316SS and Monel fastened sets, crevice corrosion occurred inside the occluded regions of the set, when immersed in coastal seawater. The attack was more severe for 316 stainless steel set. An isolated island attack of faceted surfaces morphology was seen for 316SS set. While, a circular ring of preferential grain boundary attack appeared for Monel set, indicating an IR (voltage) drop mechanism is more likely operating. Titanium-fastened sets showed high resistance to crevice corrosion when simmered in seawater. However, for long-time exposure, the sets became more susceptible to crevice corrosion attack supported by CFRP attachment (oxygen reduction reaction taking place at the carbon fibers).

Originality/value

Evidently, titanium, stainless steels and Monel are good candidates for galvanic corrosion resistance. However, their susceptibility to crevice corrosion when coupled with CFRP is a new challenging topic that needs further investigation. This is very important today because the vast application witnessed for CFRP material. This work involves developing an original methodology for this kind of investigation and was done at advanced laboratories of SeaTech at Florida Atlantic University by the Atlantic coastline.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 3 January 2017

L.M. Quej-Ake, J. Marín-Cruz and A. Contreras

The purpose of this paper was to study the corrosion process of API X52, X60, X65, X70 and X80 steels exposed to two clay soils collected in two states of Mexico (Tabasco…

Abstract

Purpose

The purpose of this paper was to study the corrosion process of API X52, X60, X65, X70 and X80 steels exposed to two clay soils collected in two states of Mexico (Tabasco and Campeche). To saturate the soils, 60 mL of deionized water was added to simulate the conditions for dry and wet season, due to in field, the climate change could modifies the physicochemical properties of the soils for each season of the year and this generate a variable environment, which affect the electrochemical responses on steel–soil interface.

Design/methodology/approach

The corrosion evaluation was carried out simulating the conditions of deteriorated coating (bare steel); this includes steel surface exposed to clay soil affected by seasonal fluctuations in a tropical zone. These soils were characterized, without any further treatment as were found in the field (dry season). Moreover, some samples were taken and prepared to analyze in laboratory. For each soil sample, 60 mL of deionized water was added to simulate the rainy season (saturated soils). Electrochemical evaluations were carried out after 3 h of exposure time at room temperature. Because soil is a system with high resistivity and impedance, it is necessary to carry out IR-drop compensation using two platinum rods that were used as an auxiliary electrode. In addition, the IR-drop correction obtained from the experimental potentiodynamic curves was investigated.

Findings

In clay from Campeche (Clay-C), the more susceptible steel to corrosion was X65, whereas in clay from Tabasco (Clay-T), the more susceptible steel to corrosion was X80 steel. Electrochemical results show that despite higher-degree steels providing higher strength and hardness, the order of corrosion susceptibility is random, which can be attributed to different microstructures in the steels. The complexity of the corrosion process on five steels was evident when steel samples were exposed to different soils. The higher corrosion rate was obtained in X65 steel (0.5 mm/year).

Practical implications

The paper clearly identifies any implication for the research.

Originality/value

The electrochemical responses of different steels exposed in two types of clay soil explained the corrosion complexity that can be attributed to changes in physicochemical properties of the soils, which are because of changes in seasons (dry and rainy) and the microstructure of each steel related to the process of fabrication. Suggesting that the increase in mechanical properties such as hardness and resistance of the pipeline steels could not be associated with its corrosion resistance, the corrosion susceptibility is more dependent on the microstructure of the steels.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 April 1960

NEW ANTI‐FOULING SYSTEM. Localised penetration of anti‐corrosive paint systems on hulls can be caused by fouling organisms; they also encourage the growth of…

Abstract

NEW ANTI‐FOULING SYSTEM. Localised penetration of anti‐corrosive paint systems on hulls can be caused by fouling organisms; they also encourage the growth of sulphate‐reducing bacteria in slimes which tend to decompose many anti‐corrosive paints. These are only two of the effects of fouling. Although less concerned with corrosion than we are in modern times, the Phoenicians in 800 B.C. were aware of some of the other effects of fouling and used copper sheathing as an anti‐fouling measure. Similarity between the principles and materials employed then and those in use today is outstanding, for copper remains the most widely used toxic included in anti‐fouling paints. There was one period in naval history, however, when the use of copper had unfortunate results. This was in the late 19th century with the introduction of iron ships. The practice of fitting copper sheathing was carried over to iron hulls; the iron hull was immediately rendered anodic to the copper and considerable corrosion ensued, while the copper, being the cathode, failed to pass into solution and therefore its toxic qualities were lost and fouling continued unabated. The fouling problem influenced the British Admiralty towards discontinuing the use of iron ships.

Details

Anti-Corrosion Methods and Materials, vol. 7 no. 4
Type: Research Article
ISSN: 0003-5599

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