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The paper studies the effect of modification of zinc orthophosphate on the anticorrosion efficiency thereof in organic coating. The zinc orthophosphate dihydrate and tetrahydrate and the reaction of phosphate anion with hydroxyl binder groups are compared. The highest anticorrosion efficiency is reached with pigments which are modified by organic corrosion inhibitors. The highly water soluble phosphate pigments reduce the anticorrosion coating properties. The effect of cation in phosphate pigments on the corrosion inhibition was confirmed.

Phosphonic acids are good complexing agents. However, they are not good as inhibitors except for a very few. Synergistic inhibition is offered in the presence of metal cations like Ca²⁺, Mg²⁺, Zn²⁺ and others in neutral media. The zinc ion is an ideal choice. The part of zinc ions are now replaced by polymers, azoles to prepare eco‐friendly inhibitor formulations. They are also used as corrosion inhibitors in concrete, coatings, rubber blends, acid cleaners, anti‐freeze coolants, etc. Discusses the various applications of phosphonic acids and their action mechanisms.

Of late there has been a controversy among medical men upon the question of whether or not the cooking of food in aluminium receptacles may result in injury to health. Quite recently there were three letters upon this subject in one issue of the “British Medical Journal.” There are those who see in this practice a real and serious danger; others who deny the existence of any such danger; and there are many who entertain doubts upon the subject.

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.

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.

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).

The paper clearly identifies any implication for the research.

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.

The World Heritage site of Moenjodaro, located in the Indus flood plain and dating to the early Bronze Age, is believed to be the most important urban centre of the Indus valley culture. The purpose of the paper is to discuss the main conservation threats and the mechanisms of decay affecting the site and to understand the influence of soluble salts on materials such as fired brick and soil. Furthermore, the paper aims to describe the repair methods employed against salt attack and provides a scheme for site management.

In the paper a literature review is followed by laboratory experiments.

The main result is the experimental assessment of the repair materials and methods traditionally employed in Moenjodaro. No evaluation was undertaken prior to this study and this makes the work the more relevant.

A more complete and detailed study of the materials examined here might have been achieved if more samples had been analysed. The present study is therefore characterised by this limitation which, however, does not undermine the significance of the work.

The results have practical applicability to the conservation of Moenjodaro in a variety of ways. The experimental analysis of materials will be essential to determine the type of intervention required for conserving the site.

The value of this paper derives from the originality of the work done, being the first of its kind for Moenjodaro. It will be especially useful to those conservators working in the site, but also in similar sites. It stresses the importance of testing before any conservation work is carried out.

To reduce the corrosion of oil‐ and gas‐well equipment during acid treatment, the acid must be inhibited. The behaviour of N‐80 oilfield material in 15 per cent hydrochloric acid solution inhibited by different inhibitor formulations containing amine, ester and a quaternary ammonium compound was studied at 303K for five hours by the mass loss method. The corrosion rates were obtained by polarisation. Impedance studies were carried out to evaluate the performance of the inhibitor formulations. It was found that the formulation containing 3,000ppm amine, 1,000ppm ester and 1,000ppm quaternary ammonium compound was effective for the specific oil‐well tubular material.

The presence of soluble salts, especially chlorides and sulphates, at the metal/paint interface usually causes premature deterioration of the paint system. In practice, soluble salts are found heterogeneously distributed in the steel corrosion products layer and are frequently located at the base steel/rust layer interface. However, in most of the research studies carried out with the aim of establishing critical concentration levels for different paint systems, panels have been prepared by dosing the saline contaminant in an uniform way across flat and unrusted steel surfaces. In order to resolve this problem, an attempt has been made to reproduce the atmospheric corrosion process of steel in environments contaminated with SO₂ and Cl⁻, using a salt fog cabinet for the case of chlorides, and a Kesternich type cabinet for sulphates.

During offshore pipe-lay, pipe lengths with anticorrosion coating are welded together, and, to facilitate the welding process, the ends of the pipe remain uncoated. A wide range of field joint coating (FJC) types is available for coating this bare section, functioning in conjunction with the pipeline cathodic protection system to provide an anti-corrosion system or package. This paper aims to relate to two-layer type heat shrink sleeves (2LHSS), which commonly are used for FJC of concrete-weighted offshore pipelines where the sleeve typically is over-coated with a solid or foam type polyurethane “infill”. Similar sleeves also are used sometimes in exposed conditions on lines without concrete over-coating. The maximum allowable soluble salt contamination prior to application of high-performance coating systems can vary, depending upon the coating type, but typically has been set at 20 mg/m2 (de la Fuente et al., 2006). The first layer of three-layer heat shrink sleeve (3LHSS) systems for pipeline FJC, liquid epoxy, falls into this category (ISO_21809-3:2008, 2008). In contrast, the 2LHSS system does not use a liquid epoxy first layer but relies instead on the bonding of a “mastic” layer directly to the pipe metal surface. The maximum acceptable concentration of salt contamination on prepared metal surfaces prior to the application of 2LHSS has been a subject of debate and was the focus of this study. International standards for FJC do not provide a maximum salt level. However, some companies have continued to specify low thresholds for the maximum allowable salt level for 2LHSS, which can result in expensive delays in production during offshore pipe-lay. In this study, salt contamination levels of up to 120 mg/m2 were found to have no effect on peeling performance after accelerated aging by hot water immersion. Furthermore, preparation for welding and the use of potable water during ultrasonic testing procedures prior to FJC, typically reduces the salt contamination level to below 50 mg/m2 providing a strong case for the deletion of salt contamination testing for 2LHSS.

The potential risk of failure of the coating due to poor surface cleanliness/contamination was assessed by testing the adhesion between the coating and the steel substrate to which the coating is adhering, following a period of hot water immersion. Compliance with ISO 21809-3 “Annex I” requires 28 days’ immersion at maximum operating temperature. For this study, to create a severe situation, the test rings were subjected to accelerated aging by water immersion at the HSS upper specified temperature of 65°C for more than twice the specified period (ISO_21809-3:2008, 2008). Two HSS were tested; one was widely used in applications where exposure to moderate mechanical stress is required, having a high shear strength type mastic “hybrid” adhesive containing a significant proportion of amorphous polypropylene blended with tackifiers and ethylene vinyl acetate (EVA), Andrenacci et al. (2009) referred to as “Type A”. The second, referred to as “Type B”, is widely used in applications where it is covered by a layer of “infill”, typically consisting of polyurethane foam or solid polyurethane elastomer, i.e. typical design methodology for concrete coated pipelines. “Type B” HSS had a more moderate strength traditional type mastic than “Type A” containing a significant percentage of butyl rubber with asphalt, activation agents and tackifying resins. To determine how to apply the salt contamination without causing flash rust, a mini-study was completed on the steel substrate. After numerous trials, it was found impossible to not to form visible rust on the pipe surface. The extent of rusting was minimised by heating the pipe immediately after the application of the salt solution.

High levels of sea salt on power tool prepared pipe surfaces were investigated by peel testing of 2LHSS after hot water immersion and compared against peel tests undertaken prior to hot water immersion. The test conditions were considered severe: salt contamination levels of up to 120 mg/m2 applied on power tool cleaned pipe surfaces that had been aged for one year without prior grit blasting. The accelerated ageing procedure had twice the specified (ISO_21809-3:2008, 2008) water immersion duration, and the test samples had exposed edges providing the possibility for moisture to creep under the coating. The test results showed that there were no noticeable deleterious effects on the performance of the two most commonly used FJCs, 2LHSS. Therefore, it was concluded that, as the level of salt contamination on prepared pipe surfaces after wet non-destructive testing typically is much lower than the levels tested in this study, pipe surfaces prepared for the application of 2LHSS type do not require specific additional measures to further reduce salt contamination, provided that care is taken to ensure that these conditions are maintained consistently during pipe laying operations.

The frequency of salt contamination testing of power tool cleaned surfaces prior to mastic type heat shrink sleeves can be minimised, and perhaps omitted entirely, provided the above criteria are satisfied.

A literature review revealed there was little published information on the testing of 2LHSS and nothing related to hot water immersion testing. Hence, the results of this investigation have provided useful industrial data regarding the effect of hot water ageing and the influence of surface salt contamination on field joint corrosion prevention capabilities.

Because of the properties of loess, the occurrence of collapse following deformation of a large settlement is a common problem during the excavation of tunnels on loess ground. Hence, risk management for safer loess tunnel construction is of great significance. The purpose of this paper is to explore the influence of factors on collapse risk of loess tunnels and establish a risk assessment model using rough set theory and extension theory.

The surrounding rock level, groundwater conditions, burial depth, excavation method and support close time were selected as the factors and settlement deformation was the verification index for risk assessment. First, using rough set theory, the influence of risk factors on the collapse risk of loess tunnels was calculated by researching engineering data of excavated sections. Then, a collapse risk assessment model was developed based on extension theory. As the final step, the model was applied to practical engineering in the Loess Plateau of China.

The weights of surrounding rock level, groundwater conditions, burial depth, excavation method and support close time obtained using rough set theory were respectively 10.811 per cent, 18.919 per cent, 24.324 per cent, 40.541 per cent and 5.406 per cent. The assessment results obtained using the model were in good agreement with field observations.

This study highlights key points in collapse risk management of loess tunnels, which could be very useful for future construction methods. The model, using easily obtained parameters, helps in predicting the collapse risk level of loess tunnels excavated under different geological conditions and by different construction organizations and provides a reference for future studies.

Studies the various contemporary standard brick products that are available and examines in detail their inherent properties and classifications which ensures that British bricks conform to the requirements of British Standards Specifications. These properties are significant and the engineer and architect must give them due consideration, for it is their responsibility to ensure they specify correctly for particular applications, and in so doing they should bear in mind that all bricks are not necessarily appropriate for all applications. This information will help professionals to make well‐considered judgements on brick selection and application.