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The inhibition efficiency of sodium gluconate (SG) in controlling corrosion of carbon steel immersed in the environment containing 60 ppm Cl^– has been evaluated in the presence and absence of Zn²⁺ by weight loss method. SG and Zn²⁺ show a synergistic effect. The protective film has been analysed by FTIR and fluorescence spectra. The protective film consists of Fe²⁺‐gluconate complex and Zn(OH)₂. The film is found to be UV‐fluorescent. The IE of the SG‐Zn²⁺ system increases in the presence of Na₂SO₄; but decreases in the presence of Na₂SO₃ and also in the presence of N‐cetyl‐N,N,N‐trimethyl ammonium bromide. This study reveals that the transporting phenomenon plays a larger role than the scavenging of dissolved oxygen.

To evaluate the inhibition efficiency (IE) of polyvinyl alcohol (PVA) in controlling the corrosion of carbon steel immersed in neutral aqueous solutions containing 60 ppm of Cl⁻, in the absence and presence of Zn²⁺. To investigate the influence of sodium sulphite (Na₂SO₃), sodium dodecyl sulphate (SDS), pH and duration of immersion on the IE of PVA‐Zn²⁺ system. To analyse the protective film formed on the metal surface.

The IE has been evaluated by weight loss method. The protective film was analysed by FTIR and fluorescence spectra.

A formulation consisting of 100 ppm of PVA and 75 ppm of Zn²⁺ offered 81 per cent IE to carbon steel immersed in a solution containing 60 ppm of Cl⁻. A synergistic effect on inhibition of a combination of PVA and Zn²⁺ was observed during the tests. The protective film consisted of the Fe²⁺‐PVA complex and Zn(OH)₂. It was found to be UV‐fluorescent. When SDS was added to the PVA‐Zn²⁺ system, the mixture showed maximum IE at the critical micelle concentration (200 ppm) of SDS (an anionic surfactant). The oxygen‐scavenging effect of Na₂SO₃ increased as the concentration of Na₂SO₃ was increased. At lower concentrations of Na₂SO₃, the transport of the inhibitors played a more major role than did the removal of dissolved oxygen. As the pH value was increased, the IE of the PVA‐Zn²⁺ system decreased. As the duration of immersion was increased, the IE was observed to decrease.

Electrochemical studies such as polarization and AC impedance spectra will enlighten more on the mechanistic aspects of corrosion inhibition.

If this study is carried out at high temperature under simulated conditions, the findings may find applications in cooling water systems.

The role of transport of inhibitors towards the metal surface from the bulk of the solution, formation of micelles by surfactants, removal of dissolved oxygen by oxygen scavenger, competition between formation of insoluble iron‐inhibitor complex on metal surface and formation of soluble iron chloride in influencing the inhibitive property has been investigated. The protective film was analysed by FTIR spectra and fluorescence spectra.

This paper aims to evaluate the corrosion inhibition capacities of synthesized compounds 1-(2-pyridinyl)-2-(o, m-, p-hydroxyphenyl) benzimidazoles in API 5L X52 steel/HCl 1M corrosion system.

Electrochemical impedance spectroscopy technique was used.

The studies determined that under stagnant conditions, the durability and efficiency were maintained over 80 per cent for up to 500 h of immersion, while the residence time started to decrease after 150 h at the best inhibitor concentration (150 ppm).

This work may help to attenuate corrosion problems in the petroleum industry.

It is the first time that 1-(2-pyridiniy)-2-(o-, m-, p-hydroxyphenyl) benzimidazoles were evaluated as corrosion inhibitors.

Phosphonates have shown synergistic effects in combination with Zn²⁺ ions in controlling the corrosion of carbon steel immersed in neutral aqueous environments containing 60‐ppm Cl^‐. The role of phosphonates in the presence of Zn²⁺ ions has been investigated by polarisation tests and weight loss results. It was observed that the phosphonates functioned as transporters of Zn²⁺ ions from the bulk of the solution towards the metal surface. The phosphonate‐Zn²⁺ bond is sufficiently strong to carry Zn²⁺ ions from the bulk solution towards the metal surface, but is weak enough for them to break to form a phosphonate‐Fe²⁺ bond at anodic sites on the metal surface. Inhibition efficiency increases when the phosphonate‐Zn²⁺ complex remains in solution in soluble form. Inhibition efficiency decreased when the phosphonate‐Zn²⁺ complex was precipitated in the bulk of the solution.

The purpose of this paper is to investigate the effect of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and blended formulations on the corrosion inhibition of aluminium in HCl solutions at 30-60°C and to study the mechanism of action.

The inhibitive effect of the homopolymers and polymer blend was assessed using weight loss and hydrogen evolution methods at 30 and 60°C. The morphology of the corroding aluminium surface without and with the additives was visualized using atomic force microscopy. The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition and type of adsorption.

Results obtained show that inhibition efficiency (η%) increases with increase in concentration of the polymers but decreases with increase in temperature. The inhibition efficiency of the homopolymers and their blends decreased with rise in temperature. Inhibition efficiency was found to be synergistically enhanced on blending the two homopolymers with highest inhibition efficiency obtained for (PEG:PVP) blending ratio of 1:3. The phenomenon of physical adsorption is proposed from the trend of inhibition efficiency with temperature.

The mechanistic aspect of the corrosion inhibition can be better understood using electrochemical studies such as potentiodynamic polarization and electrochemical impedance spectroscopy.

Studies involving the use of polymer blends/mixtures as corrosion inhibitor for metals in corrosive environments are scarce. The results suggest that the mixture could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the use of polymer–polymer mixtures to control acid-induced corrosion of metal.

This paper aims to evaluate the inhibition efficiency (IE) of oxalate ions in controlling corrosion of aluminum at pH 10.

The IE has been determined by the classical weight loss method. The corrosion behavior of aluminum was investigated by using potentiodynamic polarization and electrochemical impedance measurements. Ultra violet (UV)-visible and Fluorescence spectra have been used to analyze the film formed on the aluminum surface after immersion.

The maximum IE was 88 per cent, which was offered by a mixture of 250 ppm oxalate ions and 50 ppm [Zn²⁺]. Potentiodynamic polarization data revealed that the protective film was formed on the metal surface. UV-visible and Fluorescence spectra indicated the presence of Al³⁺−oxalate complex in the protective film formed on aluminum substrate after immersion in [OX]/[Zn²⁺] solution.

The findings of this work shed more light on the corrosion inhibition of aluminum by oxalate self-assembling monolayers.

The re-use of good design solutions is a key source of evidence and knowledge in the design of healthcare buildings. However, due to the unique nature of healthcare built environments, the critical application of this evidence is of paramount importance. The purpose of this paper is to investigate the features of such critical application and identify the aspects that need to be considered during the re-use of good designs.

Data from three case studies of hospital designs in the UK were used to explore the processes behind the adaption and re-use of design solutions during the design of healthcare buildings. Data were thematically analysed to distinguish the aspects that should be carefully compared and contrasted during design re-use.

Existing designs of healthcare buildings should be captured and evaluated along with: patient demographics, care models of the hospital, other local departmental needs and facility operational aspects in order to ensure the effectiveness of re-use. In addition, properly introducing the design to the users is also a part of successful design re-use.

The findings of this research were integrated into a framework to support healthcare designers on the effective re-use of good designs. This data-driven framework could be validated further with design practitioners. Further, this research relied on memory recall of the interviewees and the accuracy and completeness of documentary records.

This research provides details of how healthcare built environment designs are embedded in project-unique circumstances. The results could therefore be used to develop meaningful and informative evaluation mechanisms for new and re-used healthcare building design features.

This research extends the understanding of the critical application of healthcare design evidence, by explaining how healthcare design solutions should be evaluated during the design process.

The purpose of this paper is to develop an effective method for predicting the dynamic ultimate bearing capacity of porous plates, and to analyse the influence of various geometric and boundary parameters on the ultimate bearing capacity of the plates.

The goal of this paper is to propose a generalized constrained differential quadrature method to investigate the dynamic ultimate bearing capacity of perforated plates with elastically restrained edges in which the perforated plate is modelled as the assembly of continuous plate elements using the penalty function method.

The effects of size and location of the cut-out, aspect ratio of the cut-out, elastic restrained edge stiffness and compression–shear load on the dynamic ultimate bearing capacity of plates are examined and discussed in detail.

A fast method for calculating the dynamic ultimate bearing capacity of perforated plate structures was proposed, and the influence of various geometric and boundary parameters on their ultimate bearing capacity was discussed, which is of great significance for the initial design of engineering structures.

Stiffened plates have been widely used in civil, marine, aerospace engineering. As a kind of thin-walled structure operating in complex environment, stiffened plates mostly undergo a variety of dynamic loads, which may sometimes result in large-amplitude vibration. Additionally, initial stresses and geometric imperfections are widespread in this type of structure. Furthermore, it is universally known that initial stresses and geometric imperfections may affect mechanical behavior of structures severely, particularly in dynamic analysis. Thus, the purpose of this paper is to study the stress variation rule of a stiffened plate during large-amplitude vibration considering initial stresses and geometric imperfections.

The initial stresses are represented in the form of initial bending moments applying to the stiffened plate, while the initial geometric imperfections are considered by means of trigonometric series, and they are assumed existing in the plate along the z-direction exclusively. Then, the dynamic equilibrium equations of the stiffened plate are established using Lagrange’s equation as well as aforementioned conditions. The nonlinear differential equations of motion are simplified as a two-degree-of-freedom system by considering 1:2 and 1:3 internal resonances, respectively, and the multiscale method is applied to solve the equations.

The influence of initial stresses on the plate, stresses during internal resonance is remarkable, while that is moderate for initial geometric imperfections. (Upon considering the existence of initial stresses or geometric imperfections, the stresses of motivated modes are less than the primary mode for both and internal resonances). The influence of bidirectional initial stresses on the plate’s stresses during internal resonance is more remarkable than that of unidirectional initial stresses. The coupled vibration in 1%3A2 internal resonance is fiercer than that in internal resonance.

Stiffened plates are widely used in engineering structures. However, as a type of thin-walled structure, stiffened plates vibrate with large amplitude in most cases owning to their complicated operation circumstance. In addition, stiffened plates usually contain initial stresses and geometric imperfections, which may result in the variation of their mechanical behavior, especially dynamical behavior. Based on the above consideration, this paper studies the nonlinear dynamical behavior of stiffened plates with initial stresses and geometrical imperfections under different internal resonances, which is the originality of this work. Furthermore, the research findings can provide references for engineering design and application.

The purpose of this study is to analyze from multiple perspectives, so as to form an effective massive open online course (MOOC)personalized recommendation method to help learners efficiently obtain MOOC resources.

This study introduced ontology construction technology and a new semantic association algorithm to form a new MOOC resource personalized recommendation idea. On the one hand, by constructing a learner model and a MOOC resource ontology model, based on the learner’s characteristics, the learner’s MOOC resource learning preference is predicted, and a recommendation list is formed. On the other hand, the semantic association algorithm is used to calculate the correlation between the MOOC resources to be recommended and the learners’ rated resources and predict the learner’s learning preferences to form a recommendation list. Finally, the two recommendation lists were comprehensively analyzed to form the final MOOC resource personalized recommendation list.

The semantic association algorithm based on hierarchical correlation analysis and attribute correlation analysis introduced in this study can effectively analyze the semantic similarity between MOOC resources. The hybrid recommendation method that introduces ontology construction technology and performs semantic association analysis can effectively realize the personalized recommendation of MOOC resources.

This study has formed an effective method for personalized recommendation of MOOC resources, solved the problems existing in the personalized recommendation that is, the recommendation relies on the learner’s rating of the resource, the recommendation is specialized, and the knowledge structure of the recommended resource is static, and provides a new idea for connecting MOOC learners and resources.