Xiaohu Wen, Xiangkang Cao, Xiao-ze Ma, Zefan Zhang and Zehua Dong
The purpose of this paper was to prepare a ternary hierarchical rough particle to accelerate the anti-corrosive design for coastal concrete infrastructures.
Abstract
Purpose
The purpose of this paper was to prepare a ternary hierarchical rough particle to accelerate the anti-corrosive design for coastal concrete infrastructures.
Design/methodology/approach
A kind of micro-nano hydrophobic ternary microparticles was fabricated from SiO2/halloysite nanotubes (HNTs) and recycled concrete powders (RCPs), which was then mixed with sodium silicate and silane to form an inorganic slurry. The slurry was further sprayed on the concrete surface to construct a superhydrophobic coating (SHC). Transmission electron microscopy and energy-dispersive X-ray spectroscopy mappings demonstrate that the nano-sized SiO2 has been grafted on the sub-micron HNTs and then further adhered to the surface of micro-sized RCP, forming a kind of superhydrophobic particles (SiO2/HNTs@RCP) featured of abundant micro-nano hierarchical structures.
Findings
The SHC surface presents excellent superhydrophobicity with the water contact angle >156°. Electrochemical tests indicate that the corrosion rate of mild steel rebar in coated concrete reduces three-order magnitudes relative to the uncoated one in 3.5% NaCl solution. Water uptake and chloride ion (Cl-) diffusion tests show that the SHC exhibits high H2O and Cl- ions barrier properties thanks to the pore-sealing and water-repellence properties of SiO2/HNTs@RCP particles. Furthermore, the SHC possesses considerable mechanical durability and outstanding self-cleaning ability.
Originality/value
SHC inhibits water uptake, Cl- diffusion and rebar corrosion of concrete, which will promote the sustainable application of concrete waste in anti-corrosive concrete projects.
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Xiaojing Wei, Jue Wang, Xin Shi, Feng Zhou, Duolong Gao, Xiaohu Wen and Xiankang Zhong
This paper aims to discover a highly efficient corrosion inhibitor for 45# steel in hydrochloric acid solution and reveal the mechanism of inhibitors.
Abstract
Purpose
This paper aims to discover a highly efficient corrosion inhibitor for 45# steel in hydrochloric acid solution and reveal the mechanism of inhibitors.
Design/methodology/approach
In this paper, electrochemical measurements, weight loss measurements, surface characterization and theoretical calculation are used to evaluate the inhibition performance and reveal the mechanism of inhibitors.
Findings
Results show that didecyl dimethyl ammonium chloride (DDAC), especially in combination with dodecane phenol plyoxyethylene, could provide a good protection performance for the carbon steel in hydrochloric acid. The N atoms and long alkyl chains in DDAC molecular structure play the vital role.
Originality/value
Usually, DDAC is used as the compound chemical disinfectant in oilfield sterilization, medicine and health. However, to the best of the authors’ knowledge, no study has shown that it can mitigate the corrosion of carbon steels in HCl solution.
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Qiulin Niu, Xiaohu Zheng, Ming Chen and Weiwei Ming
Titanium alloy has the excellent performance and been widely utilized in aeroengine and airframe manufacture. However, improving the understanding of all aspects of titanium alloy…
Abstract
Purpose
Titanium alloy has the excellent performance and been widely utilized in aeroengine and airframe manufacture. However, improving the understanding of all aspects of titanium alloy is necessary. The purpose of this paper is to investigate the tribological properties of two typical titanium alloys against tungsten carbide under dry friction.
Design/methodology/approach
Reciprocating ball-disc friction tests were carried out at room temperature in different loading without lubricant to investigate the friction properties of TA19/WC-Co and TC18/WC-Co friction pairs. The influence of the load on the friction coefficient and friction force was analyzed. The worn surfaces of TA19 and TC18 specimens were observed by the digital microscopy and scanning electron microscopy (SEM). And the wear mechanism was discussed.
Findings
The results show that the friction coefficients decreased with the increase in the normal load. However, the reduction in the friction coefficient for the TC18 alloy was less than that for the TA19 alloy. The dynamic friction forces with time were not quite coincident with the variation trend of the friction coefficients during the sliding friction. The results observed by the SEM and EDS revealed that several grooving were the main type of frictional wear causing the surfaces of the TA19 and TC18 alloys.
Originality/value
It is shown in the paper that the tribological property of TA19 alloy was better than that of TC18 when sliding against tungsten carbide under the dry friction conditions. The main types of damage to the TA19/WC-Co friction pair were the ploughing, the delamination fatigue associate with abrasive wear and some diffusive wear. The ploughing and abrasion were the main wear mechanisms for the surface of TC18 alloy.
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Xiaohu Deng, Mengyao Fu, Shasha Deng, Chee-Wee Tan and Zhibin Jiang
Contemporary focus on infections and deaths in the event of pandemics may distract health institutions and medical practitioners from the psychosocial consequences of the…
Abstract
Purpose
Contemporary focus on infections and deaths in the event of pandemics may distract health institutions and medical practitioners from the psychosocial consequences of the outbreak in individuals. In light of the devastation, persistency and scarcity of pandemics, it is imperative to delve into individuals' psychological state and self-preservation instincts when confronted with the environmental danger arising from pandemic conditions and the environmental restrictions being imposed.
Design/methodology/approach
Guided by the self-preservation theory, the authors advance a research model to elucidate the moderated mediation effect of secondary traumatic stress on an individual's reactions when faced with environmental danger and restriction. The authors also consider the moderating influence of environmental restriction and media use diversity. The authors subsequently validated the research model via a survey with 2,016 respondents in China. The authors employed PLS-SEM to analyze the data and assess the hypothesized paths.
Findings
Analytical results revealed that secondary traumatic stress fully mediated the impact of environmental danger on external reliance but suppresses the mediating effects on internal reliance. The authors further confirmed that environmental restriction moderated the relationship between environmental danger and reliance. Furthermore, the authors attest to the moderating influence of media use diversity on the relationship between secondary traumatic stress and external reliance.
Originality/value
This study not only extends the theoretical lens of self-preservation to public health emergencies but also yields practical guidelines for coping with pandemics. Insights from this study can be harnessed to aid populations worldwide in coping and recovering from pandemics.
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Since the late 1970s, Chinese policymakers have implemented many policies to reform their country's administrative systems for the purpose of promoting economic development. In…
Abstract
Since the late 1970s, Chinese policymakers have implemented many policies to reform their country's administrative systems for the purpose of promoting economic development. In the area of public budgeting and finance, reform policies have been introduced to improve China's taxation system, budgeting system and intergovernmental fiscal relations. The implementation of these policies has resulted in many changes and improvement to China's society and has also created new challenges to China's future development. This symposium introduction provides a brief review of the development of reform policies and a summary of five articles that examine China's revenue system, public expenditure structure, budgeting control, incentive policy, and education finance.
Fatemeh Shaker, Arash Shahin and Saeed Jahanyan
This paper aims to develop a system dynamics (SD) model to identify causal relationships among the elements of failure modes and effects analysis (FMEA), i.e. failure modes…
Abstract
Purpose
This paper aims to develop a system dynamics (SD) model to identify causal relationships among the elements of failure modes and effects analysis (FMEA), i.e. failure modes, effects and causes.
Design/methodology/approach
A causal loop diagram (CLD) has been developed based on the results obtained from interdependencies and correlations analysis among the FMEA elements through applying the integrated approach of FMEA-quality function deployment (QFD) developed by Shaker et al. (2019). The proposed model was examined in a steel manufacturing company to identify and model the causes and effects relationships among failure modes, effects and causes of a roller-transmission system.
Findings
Findings indicated interactions among the most significant failure modes, effects and causes. Moreover, corrective actions defined to eliminate or relieve critical failure causes. Consequently, production costs decreased, and the production rate increased due to eliminated/decreased failure modes.
Practical implications
The application of CLD illustrates causal relationships among FMEA elements in a more effective way and results in a more precise recognition of the root causes of the potential failure modes and their easy elimination/decrease. Therefore, applying the proposed approach leads to a better analysis of the interactions among FMEA elements, decreased system's failure rate and increased system availability.
Originality/value
The literature review indicated a few studies on the application of SD methodology in the maintenance area, and no study was performed on the causal interactions among FMEA elements through an FMEA-QFD based SD approach. Although the interactions of these elements are significant and helpful in risks ranking, researchers fail to investigate them sufficiently.
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Michele Ciotti, Giampaolo Campana and Mattia Mele
This paper aims to present a survey concerning the accuracy of thermoplastic polymeric parts fabricated by additive manufacturing (AM). Based on the scientific literature, the aim…
Abstract
Purpose
This paper aims to present a survey concerning the accuracy of thermoplastic polymeric parts fabricated by additive manufacturing (AM). Based on the scientific literature, the aim is to provide an updated map of trends and gaps in this relevant research field. Several technologies and investigation methods are examined, thus giving an overview and analysis of the growing body of research.
Design/methodology/approach
Permutations of keywords, which concern materials, technologies and the accuracy of thermoplastic polymeric parts fabricated by AM, are used for a systematic search in peer-review databases. The selected articles are screened and ranked to identify those that are more relevant. A bibliometric analysis is performed based on investigated materials and applied technologies of published papers. Finally, each paper is categorised and discussed by considering the implemented research methods.
Findings
The interest in the accuracy of additively manufactured thermoplastics is increasing. The principal sources of inaccuracies are those shrinkages occurring during part solidification. The analysis of the research methods shows a predominance of empirical approaches. Due to the experimental context, those achievements have consequently limited applicability. Analytical and numerical models, which generally require huge computational costs when applied to complex products, are also numerous and are investigated in detail. Several articles deal with artificial intelligence tools and are gaining more and more attention.
Originality/value
The cross-technology survey on the accuracy issue highlights the common critical aspects of thermoplastics transformed by AM. An updated map of the recent research literature is achieved. The analysis shows the advantages and limitations of different research methods in this field, providing an overview of research trends and gaps.