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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.

The purpose of this paper is to study the effects of water immersion‐freeze‐thaw treatment on the physical properties, flexural strength (FS) and morphology of wood‐polypropylene composites containing pigments.

Wood‐polypropylene composites containing brown, green and grey pigments were compounded in a conical twin‐screw extruder. A composite manufactured without any pigment addition was used as a reference. The amount of pelletized wood, polypropylene and coupling agent (MAPP) was kept constant. The moisture content, thickness swelling (TS), FS and surface colour of the composites were measured before and after water immersion‐freeze‐thaw cycling. Scanning electron microscopy (SEM) was used to study the morphology of the composites.

FS and dimensional stability were reduced after exposure to water immersion‐freeze‐thaw cycling for all composites. The surface properties (colour and roughness) of the composites also changed after exposure to water immersion‐freeze‐thaw cycling. The degree of change depended on the presence of pigment and the type of polypropylene (neat or recycled), however.

This study is a part of an ongoing study on weathering of wood‐polymer composites (WPC) containing different additives. The results of this study were obtained from accelerated laboratory experiments.

Inorganic pigments are widely used as additives in plastics, because they have an excellent UV absorption, good IR‐reflective properties and heat stability. The research revealed that metal‐containing pigments had an effect on degradation in quality of wood‐polypropylene composites exposed to water immersion‐freeze‐thaw cyclic treatment. The addition of metal‐containing pigments to composite formulation resulted in a higher susceptibility of wood‐polypropylene composites to water absorption, and as a consequence to a higher drop of FS compared to composites made without pigment. The polymer matrix plays an important role in the protection of WPC against weathering.

This paper will help in understanding possible problems in the durability of wood‐polypropylene composites compounded with metal‐based pigments when they are exposed to water immersion‐freeze‐thaw cyclic treatment.

This paper aims to investigate the mechanical and thermal behavior, i.e. tensile strength, hardness, impact strength and glass transition temperatures of water-treated polyamide6/boric oxide (PA) composites.

The PA6 and PA6/boric oxide composites were exposed to an open environment and immersed in water for 15 days to analyze the effect of environmental humidity and frequent water immersion conditions on the composite’s mechanical and thermal properties. The tensile strength, elastic modulus, hardness and impact strength of materials were measured to identify the mechanical properties. The scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) characterizations were used to see the effect of humidity/water absorption on microstructure, crystallinity and glass transition temperatures.

The testing results revealed the loss in strength, elastic modulus and hardness, while the impact resistance was improved after exposure of materials to humidity/water. SEM images clearly show the formation of voids and XRD graphs revealed the loss in crystallinity after water immersion. The DSC plots of water immersed materials revealed the loss of glass transition temperatures up to 15°C.

The mechanical and thermal behavior of PA composites varies according to the surrounding atmosphere. Experiments were performed to investigate the influence of water treatment on the PA6/B₂O₃ composite’s mechanical and thermal properties. Water treatment resulted in the bonding between PA and water molecules, which generated voids in the materials. These voids generations are found the main reason for the low strength and hardness of water-treated materials.

To describe water absorption by the rice grains over time, diffusion and empirical models were used. Also, an optimization software was developed in this study to determine parameters and their uncertainties for the diffusion models (LS Optimizer, for partial differential equations). Parameters (and their uncertainties) for empirical models were determined by LAB Fit Curve Fitting Software.

Heat and mass diffusion phenomena are found in various processes of technological interest, including pasteurization, drying and water immersion of agricultural products, among others. The objective of this work was to study the process of water absorption by rice grains with and without husk, using diffusion and empirical models to describe the absorption kinetics. Rice grains were immersed (approximately 10 g for each experiment) in drinking water maintained at constant temperatures of 28, 40 and 50 C. In the experiments, the water contents absorbed by rice grains over time were obtained by the gravimetric method.

Among empirical models, Peleg was the most satisfactory to describe the kinetics of water absorption by rice without husk, while the Silva et alii model had the best statistical indicators for rice with husk. It was also verified that a diffusion model with boundary condition of the first kind showed the best (or equivalent) results in the description of all processes of kinetics of water absorption by rice grains, with and without husk. For grains without husk, the effective mass diffusivities were (1.186 ± 0.045) × 10⁻⁹, (1.312 ± 0.024) × 10⁻⁹ and (2.133 ± 0.028) × 10⁻⁹ m² min⁻¹, for the immersion temperatures of 28, 40 and 50C, respectively. For grains with husk, diffusivities were (0.675 ± 0.011) × 10⁻⁹ and (1.269 ± 0.017) × 10⁻⁹ m² min⁻¹, for temperatures of 28 and 50 C, respectively.

This work developed a solver for the diffusion equation in cylindrical geometry and presented the LS Optimizer software developed to determine differential equation parameters through experimental data sets.

The purpose of this study was to investigate the performances of three inhibitors in controlling corrosion of local mild steel products in distilled water and a simulated salt solution.

Corrosion inhibition of mild steel was investigated using electrochemical techniques. Untreated and inhibitor treated specimens were fully immersed in two test solutions, distilled water and the simulated solution of 2.0 wt.% NaCl and 1.0 wt.% Na2SO₄.

During full immersion in the simulated salt solution, sodium dihydrogen orthophosphate was not effective at all, resulting in even higher corrosion rates than that of the untreated specimens. Sodium benzoate was effective for three days only. Dicyclohexylamine nitrite was the most effective of them all, keeping its effectiveness for as much as 20 days. When the specimens were immersed in distilled water, all three inhibitors were effective during the 60 days of immersion while dicyclohexylamine nitrite and sodium benzoate treated specimens performed better than those treated with sodium dihydrogen orthophosphate.

The objective of this research was to investigate the performances of three inhibitors – sodium dihydrogen orthophosphate (inorganic) at 10 mM concentration, dicyclohexylamine nitrite (organic) and sodium benzoate (organic) at 100 mM concentration – in controlling the corrosion of local mild steel products fully immersed in two test solutions, distilled water and the simulated salt solution. All three inhibitors are film forming and anodic type inhibitors. According to the authors' literature review, this study is original and will add value to the studies of inhibition of steel corrosion under similar environments.

Endeavours to determine the physiological and perceptual responses to forearm cold water immersion as influenced by the use of an experimental fireproof carbonaceous insulation (ECI), Thinsulate (a commercial insulation), and Nomex flight gloves. The primary objective was to determine if ECI could provide adequate protection from cold water immersion while providing superior protection from fire. Physiological responses including rectal and skin temperatures to –1 degree C water were recorded. Perceptions of thermal discomfort and grip strength were also measured. The experimental carbonaceous insulation was able to provide better thermal protection as evidenced by significantly higher skin temperatures than the Thinsulate. Subjects perceived the Thinsulate gloves to be only slightly more comfortable than the ECI gloves. Both ECI and Thinsulate provided negligible loss of grip strength. The Nomex gloves provided virtually no thermal protection and substantial loss of grip strength post‐immersion.

The purpose of this paper is to study the inhibition of carbon steel corrosion under wet/dry conditions using electrochemical techniques.

Sodium dihydrogen orthophosphate, dicyclohexylamine nitrite and sodium benzoate were used as inhibitors in the investigation. Plain carbon steel specimens were treated with three different inhibitors for a set period of time. One group of the specimens was subjected to 60 wet/dry cycles whilst a second group was kept continuously immersed in distilled water during the same period. The corrosion rates of the specimens were determined by electrochemical methods at several intervals during corrosion.

The three inhibitors showed good performance during the whole 60 days of wet/dry cycling. Sodium dihydrogen orthophosphate was the best of the three, giving the lowest corrosion rates. However, during full immersion tests in distilled water, specimens that had been treated with dicyclohexylamine nitrite and sodium benzoate performed better than did those treated with sodium dihydrogen orthophosphate. Moreover, the corrosion rates were significantly higher in the case of wet/dry cycling due to differential aeration created through partial immersion, which was a consequence of the wet and dry cycling process.

This study showed the beneficial effect of inhibitors in slowing down the corrosion of steel. Furthermore, wet/dry cycling of steel samples in the laboratory produced corrosion rates that were comparable to those measured under actual outdoor conditions.

The purpose of this paper is to study the corrosion of the coupling of two different types of stainless steel, austenitic and ferritic, used in the fabrication of water reservoirs in the solar energy industry.

Potentiodynamic polarization and gravimetric immersion tests were used to evaluate corrosion of the coupling of two different types of stainless steel, austenitic and ferritic.

The galvanic corrosion was not significant in the case of the coupling of AISI 304 and 444 steels. The difference of the open circuit potentials obtained for the AISI 304 and AISI 444 steels was 28 mV for the polished samples. The galvanic current density (i_g) was 55 nA/cm². The corrosion observed in the stainless steel couple was in the weld area.

The methodology used is adequate to evaluate generalized galvanic corrosion. The problem of the corrosion in the coupling of the stainless steels is a problem of localized corrosion and the observed 28 mV potential difference was lower than the dispersion of results usually obtained from readings of corrosion potentials in electrochemical cells.

The use of two different types of steel in contact with each other may lead to galvanic corrosion, and the welding of steel pieces may lead to several corrosion problems. Since the boiler may be used in different countries, subject to a great diversity of water quality, corrosion may be a significant problem.

Literature data of the AISI 444 steel corrosion behaviour are still scarce. The coupling of two different stainless steels (AISI 304 and 444) in the water reservoir manufacturing was a necessary requirement of the solar energy industry. The manufacturers of boilers must evaluate and quantify the corrosion processes, which occur in the equipment used in the solar energy industry. As the solar energy industry has matured in the last ten years, the corrosion of this equipment may be a significant problem in due course.

This paper aims to analyse the coating behaviour in corrosion environment as well as to evaluate the best percentage amount of copper oxide and copper needed for organic coating in order to prevent the corrosion degradation. Electrochemical impedance spectroscopy (EIS) studies have been conducted in order to evaluate the corrosion performance of polyester-epoxy-copper oxide and polyester-epoxy-copper coating systems.

The availability of this modem instruments is used to obtain impedance data as well as computer programs to interpret the results that made the technique popular. In addition, EIS is well suited to the study of polymer-coated metals.

The results showed that samples containing 25 weight per cent of copper oxide and copper (90P25CuO and 90P25Cu) obtained the excellent corrosion properties from the first day up to 30 days of NaCl immersion. The highest corrosion resistance values obtained by 90P25CuO and 90P25Cu on the 30th day were 7.107 × 108 O and 5.701 × 108 O, respectively, with lower double layer capacitance of 1.407 × 10⁻⁹ Farad and 3.935 × 10⁻⁹ Farad, respectively. Moreover, the water uptake gained by these two coating samples was the lowest at the end of immersion, which was 0.0084 for 90P25CuO and 0.1592 for 90P25Cu, showing that the sample has good corrosion performance.

This paper discussed on the highest corrosion resistance, double layer capacitance and the water uptake of the copper (Cu) and copper oxide (CuO) coating system obtained from the EIS measurements.

An investigation of the behaviour of a soluble resin coating on a steel substrate was carried out by open circuit potential and electrochemical techniques. Exposure conditions were with artificial sea‐water and natural sea‐water. The anticorrosion properties of the soluble resin material and its protection of the steel panel from marine corrosion were estimated by comparison with the untreated steel. The weight effect of the film coating and the temperature of the media were also studied.