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The purpose of this paper is to introduce a theoretical investigation of the pulse‐cathodic protection (PCP) systems to show how they behave under different operating conditions. The effectiveness of the PCP system also is highlighted for a typical large‐scale configuration. The principal technical objectives of this paper are to answer three questions: Are the PCP systems effective in the desert fields? Although they have been approved, what is the reason for their lack of effectiveness in some coastal areas? What are the operation recommendations for the currently installed PCP systems and their future application?

The factors affecting the cathodic protection of well casings have been investigated theoretically by using a 3D field approach software package current distribution, electromagnetic fields, grounding and soil structure analysis. Cathodic interference with nearby well casings has been investigated thoroughly because corrosion of this kind is more serious than the anodic type. The performance of PCP systems has been analyzed with respect to obtaining better protection‐current distribution along the protected well casing at reduced anode current, together with reduced stray current (corrosion) at any nearby unprotected structure(s).

For uncoated well casings, protection current pulses are attenuated significantly and are smoothed out to be pure direct current after about 10 percent of the well‐casing buried length. High‐magnitude stray current can be found affecting any switched‐off well casings and hence they can be corroded faster from the top part than unprotected/remote wells, as are deeper well casings that may sustain considerable localized corrosion attack on the upper portions of the casing. Without the formation of a natural protective coating with high resistivity, the PCP system becomes malfunctioning, i.e. its performance becomes very similar to that of the conventional cathodic protection (CP) systems. This effect has been confirmed by field measurements in Oman, where magnesium hydroxide is minimally formed (in desert areas).

In reality, some of the PCP modules at the same station can have a slight deviation in the operating frequency and/or voltage. It is planned, therefore, that the investigation will be extended to simulate such cases and take into account the effect of multi‐layer soils.

Knowing the performance of PCP systems for protecting deep well casings is a critical issue for the oil industry.

The paper provides a sound basis on which oil producers can take decisions about the future application of the PCP systems, optimize their performance, and introduce application restrictions by studying all factors that affect PCP performance. The effectiveness of PCP in desert (sandy/rocky) soil, where calcium‐carbonate deposition predominates over magnesium‐hydroxide formation, has proven to be very similar to that of a conventional CP system. The reliability of artificial oil‐lifting systems will be increased by reducing oil production losses (“oil deferment”) and the rig mobilization, which has very high rent cost.

Loading the impulse‐voltage generator by test object can affect the generated voltage waveform. It is well known that reconfiguring these generators by changing the high‐voltage resistors and capacitors, and even the connecting leads in the laboratory is too bulky and time consuming, especially for large test objects. The objective of this paper is to introduce a new computerized method to reconfigure the impulse‐voltage generator in order to conduct the standard tests on any type of objects.

A modified algorithm is introduced for solving the generalized equivalent circuit of impulse‐voltage generators under any loading condition.

The high efficiency of this algorithm has been verified by experimental investigations on different reduced‐ and full‐scale loads, namely, resistive, inductive, capacitive or mixed. For reduced‐scale loads up to a few kV, a single‐stage impulse‐voltage generator is used. While for full‐scale loads, a multi‐stage impulse‐voltage generator is reconfigured to test a 33 kV neutral earthing reactor. The experimental responses are compared with the numerical results of the proposed program and checked out by the PSCAD simulation. Good agreement has been found between all of them.

Knowing the exact value of the test object, some of the generator components and the connecting lead inductances is a must to apply this method.

Reconfiguring of impulse‐voltage generators by changing the high‐voltage resistors and capacitors, and even the connecting leads in the laboratory is too bulky and time consuming, especially for large test objects. This work will certainly save time and efforts if it is applied correctly in high‐voltage laboratories.

The purpose of this study is to examine the impact of firm financial and operational characteristics on the level of forward-looking information disclosure (FLID) by Egyptian-listed non-financial companies. The present research also aims to investigate the moderating role of gender diversity on the board of directors.

The sample incorporates the non-financial companies included in the EGX 100 of the Egyptian Stock Exchange (ESE), whose reports were available during the study period from 2013 to 2018. The final sample comprises 49 companies with 294 observations. Statistical analysis is performed using multiple regression analysis.

This study found a significant positive impact of return on assets, leverage, company size and age on the level FLID, while external audit firm type and industry were found to impact the level of FLID negatively. Further, the board gender diversity (BGD) is found to have a moderating impact as it strengthens the effect of financial and operational characteristics on the level of FLID.

The present study has some implications for Egyptian companies, investors in the Egyptian market and regulators in emerging economies, which include paying more attention to BGD when selecting the board members by companies as well as following up the female representation in all the listed companies by regulators.

To the best of the authors’ knowledge, this is the first study to investigate the moderating role of BGD and its impact on the level of FLID in emerging markets. This extends the disclosure literature as the present study brings new evidence from an emerging market regarding BGD moderating role as early research concentrated on the direct impact of BGD on the level of FLID.

Concrete-filled double skin tube (CFDST) columns are considered one of the most effective steel-concrete composite sections owing to the higher load carrying capacity as compared to its counterpart concrete-filled tube (CFT) columns. This paper aims to numerically investigate the performance of axially loaded, circular CFDST short columns, with the innovative strengthening technique of providing stiffeners in outer tubes. Circular steel hollow sections have been adopted for inner as well as outer tubes, while varying the length of rectangular steel stiffeners, fixed inside the outer tubes only, to check the effect of stiffeners in partially and full-length stiffened CFDST columns.

The behaviour of these CFDST columns is investigated numerically by using a verified finite element analysis (FEA) model from the ABAQUS. The behaviour of 20-unstiffened, 80-partially stiffened and 20-full-length stiffened CFDST columns is studied, while varying the strength of steel (f_yo = 250–750 MPa) and concrete (30–90 MPa).

The FEA results are verified by comparing them with the previous test results. FEA study has exhibited that, there is a 7%–25% and 39%–49% increase in peak-loads in partially stiffened and full-length stiffened CFDST columns, respectively, compared to unstiffened CFDST columns.

Enhanced strength has been observed in partially stiffened and full-length stiffened CFDST columns as compared to unstiffened CFDST columns. Also, a significant effect of strength of concrete has not been observed as compared to the strength of steel.

This paper explores the behavior of GFRP and steel reinforced concrete columns when subjected to eccentrically axial loads. Six columns of 150^*150 mm cross section were tested. Four of them had GFRP reinforcement and two had steel reinforcement. The concrete strength of the GFRP reinforced columns was either 24.73 Mpa or 38.35 Mpa while for the steel reinforced columns it was 24.73 Mpa. The eccentricity was either 50 mm or 25 mm and the tie spacing was either 80 mm or 130 mm. Large longitudinal deformations were recorded for columns with GFRP reinforcement and for columns with large tie spacings. However, tie spacing had no notable effect on the maximum lateral deflection and ductility of GFRP columns of this research. The average maximum stress was about 60% of the concrete compressive strength for columns with initial eccentricity of 50 mm. GFRP bars recorded higher strains than steel bars and these strains were larger when the tie spacing was large. The increase in the strength of the concrete was associated with reduction in the GFRP bar strain. Two interaction diagrams were plotted for the columns and they present lower bound to the obtained experimental results.

Waste foundry sand (WFS) is a by-product of the metal casting industries and is used for land filling purposes. Disposing of waste creates problems to environment and increases disposal values. To reduce environmental pollutions and solving disposal problems, several authors in worldwide are carried out research work by partial and complete replacing of natural sand with WFS in concrete mixtures. It is found that WFS can be used for production of structural grade concrete. The mechanical characteristics and flexural properties of RC beams has been reviewed in this paper. From this literature review, it has been noticed that there are improvements in concrete strength properties with WFS.

The results of various properties of concrete have been discussed in this review articles such as compressive strength, split tensile strength, flexural strength, modulus of elasticity, SEM micro-structures and flexural strength properties of RC beams.

From the literature review, it is found that there is gap of research on flexural behavior of reinforced concrete beam with WFS.

By using WFS effectively, the environmental pollutions and dumping of waste can be reduced. WFS can be successfully used in structural concrete members.

The structural behavior of reinforced concrete (RC) beams made with waste foundry sand (WFS) was examined in this study by using investigational data. Five RC beams were tested in this present work, four beams with varying WFS content and one beam with natural aggregates. The factors considered for studying the flexural performance of RC beams were WFS content (10%, 20%, 30% and 40%), 15% Ground Granulated Blast Furnace Slag (GGBS) is used as supplementary cementitious (SCM) content for all beams and tension reinforcement ratio (0.95%). The crack pattern of the RC beams with WFS (RCB1, RCB2, RCB3 and RCB4) was similar to that of referral beam–RCB0. The RC beams made with WFS (RCB1, RCB2, RCB3 and RCB4) show lesser number of cracks than referral beam–RCB0. It is observed that RCB1 beam shows higher ultimate moment carrying capacity than other RC beams. A detailed assessment of the investigational results and calculations based on IS: 456-2000 code for flexural strength exhibited that the present provisions conservatively predicts the flexural strength and crack width of RC beams with WFS and 15% GGBS. It is suggested that 10% WFS can be used to make RC beam.

In this present work, four RC beams made WFS and one RC beam made with natural aggregates. 15% GGBS is used as SCM for all RC beams. After casting of RC beams, the specimens were cured with wetted gunny bags for 28 days. After curing, RC beams like RCB0, RCB1, RCB2, RCB3 and RCB4 were tested under a four-point loading simply supported condition. An assessment of investigational results and calculations as per IS: 456-2000 code provisions has been made for flexural strength and crack width of RC beams with WFS and 15% GGBS. The crack pattern is also studied.

From this experimental results, it is found that 10% WFS can be used for making RC beam. The RCB1 with 10% WFS shows better flexural performance than other RC beams. RC beams made with WFS show lesser number of cracks than referral beam–RCB0. IS: 456-2000 code provisions can be safely used to predict the moment capacity and crack width of RC beams with WFS and 15% GGBS.

By utilization of WFS, the dumping of waste and environmental pollution can be reduced. By experimental investigation, it is suggested that 10% WFS can be used to make RC structural members for low cost housing projects.

The purpose of this paper is to analyze and solve abnormal variation of pipe‐to‐soil potentials of an oil‐transfer pipeline.

Pipe‐to‐soil potentials of an oil‐transfer pipeline varied abnormally at several locations. Visual detections find the pipeline is buried near an electric railway and there are several anodic ground beds nearby. Corrosion patterns of the pipeline and examination of the soil reveal no microbiological corrosion. The potential gradients indicate the pipeline might not be attacked by stray currents. However, whole day measurements of one pipeline pile show there are two kinds of stray currents influencing the pipeline: AC stray current and DC stray current.

The highest pipe‐to‐soil potential reaches 12.958 V when there are AC stray currents. In addition, the biggest and lowest DC pipe‐to‐soil potentials are 0.888 V and −5.90 V, respectively. Radiodetection pipeline current mapper measurement finds there is some bitumen coating breaking points on pipeline. These make the stray currents enter the pipeline and stray current corrosion happens easily. As a result, stray current corrosion happens.

The potential gradients cannot indicate stray current corrosion under all circumstance.

dc electrified traction systems are a potential source of stray currents. The purpose of this paper is to evaluate the harmful effects (electrolytic corrosion) that an electrified railway has on nearby earth return circuits (e.g. pipelines).

The electric circuit approach, based on the earth return circuit theory, to model stray currents interference on extended structures is presented. An exact method of calculation is applicable to any dc railway system in which tracks can be represented by a single earth-return circuit (equivalent rail) with current energization. In the approximate method, the equivalent rail with current energization is modeled as a large multinode electrical equivalent circuit with lumped parameters. The circuit is a chain of basic circuits, which are equivalents of homogenous sections of the rail. The electrode kinetics (polarization phenomenon) is taken into account in the model developed.

Formulas in partially closed forms are derived applicable to the analysis of currents and potentials along a pipeline laid in the proximity with railway tracks. The attempt is undertaken, to incorporate the electrode kinetics into the simulation model in which the polarization phenomenon (Tafel equation) is modeled by a non-linear voltage source with source voltage being iteratively calculated. The polarization potential along the affected pipeline can be determined.

The pipeline electrochemical response (polarization behavior – non-linear phenomenon on the interface metal-soil electrolyte) to the dc stray currents interference is innovative incorporated into the simulation model with lumped parameters using the iterative process.

The purpose of this paper is to present a method to calculate the transient induced voltages along the underground pipelines and analyze the transient interference generated in the pipelines due to the inductive coupling in the fault‐to‐ground condition of power lines in close proximity.

Based on finite difference‐time domain method, an improved method is proposed to calculate transient inductive interference in underground metallic pipelines due to a fault in nearby power lines. The frequency‐dependent problem in the analysis of transient interference is solved in phase domain. Compared with the traditional method, the disposal of phase‐modal transformation matrices’ frequency‐dependent characteristic is avoided and the calculation is simplified by using vector fitting approach and recursive algorithm greatly in the proposed method.

A novel improved method is proposed to calculate transient induced voltage distribution along underground metallic pipelines due to a fault in nearby power lines. Results show that the peak value of transient induced voltage at the most critical point is about 1.15 times of the magnitude in the steady state without the fault removed and the analysis of transient inductive interference is necessary in the fault‐to‐ground case of power lines.

In order to mitigate the interference from power lines to nearby pipelines, pipelines should be good grounded and positioned as far away from the power line as possible. In high soil resistivity areas, the common corridor should be avoided.

The paper presents a method to calculate the transient induced voltages along the underground pipelines and analyze the transient interference generated in the pipelines due to the inductive coupling in the fault‐to‐ground condition of nearby power lines. The proposed method is general and can also be applied to other transient interference studies such as crosstalk problems of communication networks and interference between power lines and aboveground pipelines or communication cables. Effects of various parameters upon the inductive interference generated in underground pipelines due to a fault in nearby power lines are analyzed to be a guide for controlling the inductive interference.