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This paper aims to study the influence of NaNO₂ on the chemical composition of passivation film.

X-ray photoelectron spectroscopy and X-ray diffraction were selected to determine the composition of passivation film of steel bars in mortar. The specimens were exposed to the chloride solution, carbonation environment and the coupling effects of chloride solution and carbonation. The chemical composition and micro structures at 0 and 5 nm from the outer surface of the passivation film of steel bars were analyzed.

Results showed that the nitrite inhibitor improved the forming rate of the passivation film and increased the mass ratio of Fe₃O₄ to FeOOH on the surface of steel bars. The component of Fe₃O₄ at 5 nm of the steel passivation film was more than that at 0 nm. Sodium ferrite in the pore solution was easily hydrolyzed and then FeOOH was formed. Therefore, due to the nitrite inhibitor, a “double layer structure” of the passivation film was formed to prevent steels bars from corrosion.

This is original work and may help the researchers further understand the mechanism of rust resistance by nitrite inhibitor.

Based on clarifying the structural difference between jade fibre and general polyester fibre, this paper aims to study the dyeing properties and dyeing adsorption mechanism of jade fibre with disperse dye and cationic dye.

The chemical structure and microstructure of jade fibre were briefly explained comparing with ordinary polyester fibre. The dyeing rate curve and dyeing adsorption isotherm of disperse dyes and cationic dyes on jade fibre were, respectively, studied. The dyeing uptake, dyeing absorption mechanism, and the main dyeing process parameters were proposed.

Jade fibre can be dyed with cationic dye and disperse dye. The suitable exhaust dyeing process is 110°C and 40 minutes for disperse dye, 100°C and 60 minutes for cationic dye. The dyeing uptake on jade fibre with both disperse dyes or cationic dyes is much higher than that on general polyester fibre and acrylic fibre, and the dyeing adsorption mechanism belongs to the combination of Langmuir and Nernst adsorption for disperse dyes and Langmuir adsorption for cationic dyes. Comparing with ordinary polyester fibre, jade fibre has the advantage of low temperature dyeing and reduced effluent, as is significant to energy-saving and emission reduction.

Jade fibre is a new type of modified polyester fibre with the function of health protection and energy conservation. There are little technical data in the literature at present about the dyeing property of jade fibre.

Two corrosion inhibitors for closed cooling water systems, nitrite-based and mixture of nitrite and molybdate corrosion inhibitor, are often compared to each other. This study aims to optimize these two inhibitors in terms of concentration and pH for carbon steel protection, with insights into the double layer structure on surface and its impact on corrosion inhibition.

Electrochemical analysis including electrochemical impedance spectroscopy and potentiodynamic test are carried out for quick assessment of corrosion inhibition efficiency and optimization, which is confirmed by immersion test and microscopic analysis. The electronic properties of the surface film are analyzed through Mott–Schottky method which provides new insights into the inhibition mechanism and the role of each component in mixture inhibitor.

Mixture of nitrite and molybdate is shown to present higher inhibition efficiency, owning to the double layer structure. Nitrite alone can form a protective surface film, whereas molybdate leads to an n-type semiconductive film with lower donor density, hence giving rise to a better inhibition effect.

Surface after inhibitor treatment has been carefully characterized to the microscopic scale, implying the effect of micro-structure, chemical composition and electronic properties on the corrosion resistance. Inorganic corrosion inhibitors can be tuned to provide higher efficiency by careful design of surface film structure and composition.

Almost every study on corrosion inhibitor applies such method for quick assessment of corrosion inhibition effect. Mott–Schottky test is one of electrochemical methods that reveals the electronic properties of the surface film. Previous works have studied the surface layer mainly through X-ray photoelectron spectroscopy. This study provides another insight into the surface film treated by nitrite and molybdate through Mott–Schottky analysis, and relates this structure to the corrosion inhibition effect based on multiple analysis including electrochemistry, microscopic characterization, thermodynamics and interface chemistry.

The purpose of this paper is to point out the possibilities for friction welding of dissimilar steels which are used in various industries. In addition, friction welding is a welding method that is applied for executing the very responsible joints. This research is focused on friction and tribological processes in the friction plane of the two pieces during the welding.

The present study research has been conducted based on the experimental testing of cylindrical specimens and results are analyzed.

The austenite grain size is affected by several factors through the friction process phase and the compacting phase during the welding. The very fine grain is the consequence of the high degree of the plastic deformation of the near-the-contact layers even in the friction phase. The viscous layer, which is formed during the stable friction phase, is the area where the moving of matter occurs according to a very complex mechanism.

The paper contains useful results from the area of conventional friction welding of dissimilar steels and it can be very useful to researchers and engineers who deal with similar problems.

Longitudinal facial cracks (LFC) are one of the major defects occurring in the continuous-casting stage of thin slab caster using funnel molds. Longitudinal cracks occur mainly owing to non-uniform cooling, varying thermal conductivity along mold length and use of high superheat during casting, improper casting powder characteristics. These defects are difficult to capture and are visible only in the final stages of a process or even at the customer end. Besides, there is a seasonality associated with this defect where defect intensity increases during the winter season. To address the issue, a model-based on data analytics is developed.

Around six-month data of steel manufacturing process is taken and around 60 data collection point is analyzed. The model uses different classification machine learning algorithms such as logistic regression, decision tree, ensemble methods of a decision tree, support vector machine and Naïve Bays (for different cut off level) to investigate data.

Proposed research framework shows that most of models give good results between cut off level 0.6–0.8 and random forest, gradient boosting for decision trees and support vector machine model performs better compared to other model.

Based on predictions of model steel manufacturing companies can identify the optimal operating range where this defect can be reduced.

An analytical approach to identify LFC defects provides objective models for reduction of LFC defects. By reducing LFC defects, quality of steel can be improved.

U.S.S.R. Oxygen and nitrogen in metallised surfaces. One of the most important considerations in the matter of extending the life of units or components under rolling friction conditions or corrosion is the use of different pseudo‐alloys on a steel base, and the chemical composition and nature of these ‘alloys,’ especially in the matter of oxygen and nitrogen content. Electro‐metallising is briefly described. The micro‐structure of a steel metallised pseudo‐alloy is shown and discussed. Characteristic features are porosity and heterogeneity, the former amounting to 10 to 15%. Methods of analysis, especially for oxygen and nitrogen, include anodic solution and separation of non‐metallic inclusions (including oxides) in powder form. Nitrogen content averaged 0.13% and oxygen 2.7% (without manganous oxide). An x‐ray study was made of the phase constitution of non‐metallic inclusions, with tabulated results and x‐ray photographs. Analyses of the pseudo‐alloys for carbon manganese, sulphur, phosphorus and silicon are also tabulated. —(L. V. Krasnichenko et al., Zh. prikl. Khim. (J. Appl. Chem.), 1958, (8), 1170–1174.)

Low-temperature plasma (LTP) has been increasingly employed for polymer surface modifications. In this paper, plasma gases of oxygen and argon were used for pre-treating polyester fabrics before conducting chemical silver plating, aiming to increase the amount of metal content and improve the performance of the polyester fabrics. After LTP pre-treatment, there was a thin plasma layer generation on the fabric surface which was in good contact with the fibre. Based on the observation of micro-structure using scanning electron microscopy (SEM), it was found that there was an increase in the amount of silver particles deposited on the fibre surface after the LTP pre-treatment. The surface observation implies that the LTP pre-treatment could enhance the hydrophilicity of fibre surface and help facilitate the absorption of silver particle layer to reach the necessary level of uniformity and adhesive strength.

Efficient numerical assessment of performance is particularly important in digital material design of porous materials. This study aims to present an up-scaled approach to virtually investigate permeation of fluids through a real porous filter membrane with a heterogeneous micro-structure.

The method of asymptotic homogenization is applied. The structural parameters of the micro-structure are directly obtained from structural equation modeling image analysis of a commercial filter membrane without fitting procedures. The simulation results are compared to permeation experiments of gaseous nitrogen and liquid water.

The authors found that variations in the pressure gradients across the membrane, resulting from the heterogeneity of pore structure, need to be considered. Remarkable agreement between simulations and experiments is observed.

Despite some research in the field of filtration, no studies on filter membranes have been published yet, although they represent a large segment of filtration technology.

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.

To improve the electrochemical corrosion resistance of cold sprayed Al coating.

A cold sprayed aluminum (Al) coating fabricated on S355 structural steel was oxidized using a micro arc oxidation (MAO). The electrochemical corrosion and impedance spectroscopy were tested to investigate its corrosion performance.

The MAO film is primarily α-Al₂O₃ and γ-Al₂O₃, which increases its density and surface quality. The corrosion potential is positively shifted by 0.2 V, and the electrochemical impedance is significantly increased.

A cold sprayed Al coating on S355 steel was first oxidized using a MAO. The effects of MAO on the microstructure of Al coating were investigated to analyze its electrochemical corrosion behavior.