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Article
Publication date: 9 April 2021

Cheng Zhang, Cheng Peng, Jin Huang, Yanchun Zhao, Guangsheng Huang, Liang Wu, Guangang Wang and Hua Zhang

The influence of Zn concentration on microstructure and corrosion performance of the Mg–xZn alloys microalloyed with Ca and Ce was investigated through optic microscopy…

Abstract

Purpose

The influence of Zn concentration on microstructure and corrosion performance of the Mg–xZn alloys microalloyed with Ca and Ce was investigated through optic microscopy, scanning electron microscopy, hydrogen evolution, dynamic polarization and electrochemical impedance spectroscopy experiments.

Design/methodology/approach

In this paper, Mg–xZn alloys (x = 0.5∼2.0 Wt.%) microalloyed with Ca and Ce (0.2 Wt.% each) were prepared.

Findings

As the increase of Zn concentration, the number of second phase particles (Mg-Zn-Ca, Mg-Zn-Ce and Mg-Ce phases) increased, and when the Zn concentration increased to 2.0 Wt.%, the new second phase Mg-Zn phase was precipitated.

Originality/value

The influence of Zn concentration on corrosion mechanism of Mg-xZn alloys microalloyed with Ca and Ce was revealed. Increasing of the Zn concentration resulted in the intensification of galvanic corrosion. When Zn concentration was 0.5 Wt.%, the alloy showed the lowest corrosion rate (0.61 mm y-1), which was about 1/2 of that of Mg-2.0Zn-0.2Ca-0.2Ce alloy.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 5 September 2020

Cheng Zhang and Zehao Ye

Owing to the consumption of considerable resources in developing physical pipe prediction models and the fact that the statistical models cannot fit the failure records…

Abstract

Purpose

Owing to the consumption of considerable resources in developing physical pipe prediction models and the fact that the statistical models cannot fit the failure records perfectly, the purpose of this paper is to use data mining method to analyze and predict the risks of water pipe failure via considering attributes and location of pipes in historical failure records. One of the Automatized Machine Learning (AutoML) methods, tree-based pipeline optimization technique (TPOT) was used as the key data mining technique in this research.

Design/methodology/approach

By considering pipeline attributes, environmental factors and historical pipeline broke/breaks records, a water pipeline failure prediction method is proposed in this research. Regression analysis, genetic algorithm, machine learning, data mining approaches are used to analyze and predict the probability of pipeline failure. TPOT was used as the key data mining technique. A case study was carried out in a specific area in China to investigate the relationships between pipeline broke/breaks and relevant parameters, such as pipeline age, materials, diameter, pipeline density and so on.

Findings

By integrating the prediction models for individual pipelines and small research regions, a prediction model is developed to describe the probability of water pipe failures and validated by real data. A high fitting degree is achieved, which means a good potential of using the proposed method in reality as a guideline for identifying areas with high risks and taking proactive measures and optimizing the resources allocation for water supply companies.

Originality/value

Different models are developed to have better prediction on regional or individual pipeline. A comparison between the predicted values with real records has shown that a preliminary model has a good potential in predicting the future failure risks.

Details

Facilities, vol. 39 no. 1/2
Type: Research Article
ISSN: 0263-2772

Keywords

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Article
Publication date: 3 January 2018

Cheng Zhang, Kee Cheok Cheong and Rajah Rasiah

This study aimed at investigating the influence of corporate governance on firm risk during the Chinese state enterprise reform. The purposes of this study are to examine…

Abstract

Purpose

This study aimed at investigating the influence of corporate governance on firm risk during the Chinese state enterprise reform. The purposes of this study are to examine the effects of board independence, state ownership and other governance variables on firm risk and to check the influence of controlling shareholder types on firm risk.

Design/methodology/approach

This study uses the dynamic and static panel model to estimate the effects of board independence, state ownership and other governance factors on return volatility. To examine the influence of controlling shareholder types on corporate risk-taking, this study further used the treatment effect model (or sample selection model) to analyze the effect of private, state-owned enterprise (SOE) entity, central government and local government controls on corporate risk-taking.

Findings

It was found that the enforcement of board independence significantly increases firm risk. The strategy of decentralizing state enterprises (from central government to local government) is a good way to achieve stable stock returns.

Originality value

This study contributes to existing knowledge in several ways. First, it focused on independent directors rather than on the size of the corporate board. Second, it highlighted the impacts of state ownership and control on corporate risk. Instead of treating all types of state ownership as homogenous, SOEs are further classified into directly controlled and indirectly controlled, in line with prior studies.

Details

Corporate Governance: The International Journal of Business in Society, vol. 18 no. 2
Type: Research Article
ISSN: 1472-0701

Keywords

Open Access
Article
Publication date: 20 October 2021

Kun-cheng Zhang, Xin-chang Guo, Shi-zheng Tian, Qi Cui, Mao-chong Shi and Pei-fang Guo

Many experts suggest that the human being explore marine resources and marine new energy sources to alleviate the shortage of land resources and the ecological…

Abstract

Purpose

Many experts suggest that the human being explore marine resources and marine new energy sources to alleviate the shortage of land resources and the ecological degradation. However, island coastal zones are considered to be fragile ecosystems; their geographical location and natural characteristics, their biodiversity and associated ecosystems, and their exposure to diverse land and sea conditions all make them highly vulnerable to environmental changes and human activities. Therefore, it is necessary to achieve the goals of environmental protection and sustainable development on the basis of a comprehensive evaluation and understanding of islands.

Design/methodology/approach

Due to the importance of island groups, this paper conducts evaluation studies on them. Using the Delphi, AHP and TOPSIS methods, this study evaluated quantitatively the comprehensive development level and comprehensive development potential of island groups in terms of resources, natural environment, economy and society. Innovatively using them as two subsystems, the present study combined the coupling coordination model and the obstacle factor calculation method.

Findings

The prospective index of comprehensive development was applied to the Changdao Island Group in Yantai, Shandong Province as an example, and the final evaluation revealed that the comprehensive development prospect of this island group had an upward trend from 2010 to 2017. Future efforts should be made to improve its economic and social conditions and economic development status, apart from promoting its comprehensive development by improving human resources management, increasing the GDP growth rate, and improving fresh water and electricity supply.

Originality/value

This study takes the integrated development level of the island and the integrated development potential of the island as two subsystems, and the innovative application of the coupling coordination degree model is used to calculate the integrated development index of the island to understand the development status of the island area. On the basis of this model, the obstacle factor identification method is designed to identify the main obstacle factors, and on the basis of evaluation and identification, specific measures to ensure the sustainable development of the island area are effectively proposed.

Details

Marine Economics and Management, vol. 4 no. 2
Type: Research Article
ISSN: 2516-158X

Keywords

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Book part
Publication date: 14 October 2019

Sameer Mathur and Ashish Dubey

This paper identifies and models the effect of eight attributes that influence hotel room rents in India. These attributes are conceptually grouped into three factors: (1…

Abstract

This paper identifies and models the effect of eight attributes that influence hotel room rents in India. These attributes are conceptually grouped into three factors: (1) site factors including the presence or absence of a “swimming pool,” “free breakfast,” and the “hotel capacity”; (2) situational factors including, “distance from the airport,” “weekend/weekday,” “city population,” “cost of living”; and (3) a reputation factor indicated by “star rating.” Our regression model uses secondary data collected from a hotel booking website for 570 hotels across 18 cities of India. The results indicate that six out of these eight variables namely, presence of swimming pool, free breakfast, hotel capacity, distance from the airport, city population, and hotel star rating have a significant impact on hotel room rents in India.

Details

Advances in Hospitality and Leisure
Type: Book
ISBN: 978-1-83867-956-9

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Article
Publication date: 9 December 2019

Cheng Zhang, Liang Wu, Zilong Zhao, Guangsheng Huang, Bin Jiang, A. Atrens and Fusheng Pan

This paper aims to investigate microstructure, corrosion behavior and mechanical properties of Mg-4Li and Mg-4Li-3Al.

Abstract

Purpose

This paper aims to investigate microstructure, corrosion behavior and mechanical properties of Mg-4Li and Mg-4Li-3Al.

Design/methodology/approach

The microstructure was characterized by using scanning electron microscopy and electron backscatter diffraction. The corrosion behaviors were measured by hydrogen evolution and potentiodynamic polarization tests. The mechanical properties were evaluated by tensile tests.

Findings

The addition of Al results in the precipitation of some Mg-Al phase and Al3Li phase particles, and the formation of some fine recrystallized grains.

Originality/value

Mg-4Li-3Al showed a higher corrosion rate than that of Mg-4Li, attributed to the precipitate particles in Mg-4Li-3Al causing microgalvanic corrosion and the change of grain orientation. The addition of 3 Wt. per cent Al increased the tensile strength by solid solution strengthening, precipitation strengthening, refinement strengthening and texture strengthening, whilst the elongation decreased by almost half.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 July 2014

Shujuan Hou, Zhidan Zhang, Xujing Yang, Hanfeng Yin and Qing Li

The purpose of this paper is to optimize a new thin-walled cellular configurations with crashworthiness criteria, so as to improve the crashworthiness of components of a…

Abstract

Purpose

The purpose of this paper is to optimize a new thin-walled cellular configurations with crashworthiness criteria, so as to improve the crashworthiness of components of a vehicle body.

Design/methodology/approach

ANSYS Parametric Design Language is used to create the parameterized models so that the design variables can be changed conveniently. Moreover, the surrogate technique, namely response surface method, is adopted for fitting objective and constraint functions. The factorial design and D-optimal criterion are employed to screen active parameters for constructing the response functions of the specific energy absorption and the peak crushing force. Finally, sequential quadratic programming-NLPQL is utilized to solve the design optimization problem of the new cellular configurations filled with multi-cell circular tubes under the axial crushing loading.

Findings

Two kinds of distribution modes of the cellular configurations are first investigated, which are in an orthogonal way and in a diamond fashion. After comparing the optimized configurations of the rectangular distribution with the annular distribution of the multi-cell fillers, it is found that the orthogonal way seems better in the aspects of crashworthiness than the diamond fashion.

Originality/value

The two new thin-walled cellular configuration are studied and optimized with the crashworthiness criteria. Study on the new cellular configurations is very valuable for improving the crashworthiness of components of a vehicle body. Meanwhile, the factorial design and the factor screening are adopted in the process of the crashworthiness optimization of the new thin-walled cellular configurations.

Details

Engineering Computations, vol. 31 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 18 August 2021

Chuanbo Zheng, Cheng Zhang, Xiao Yong Wang and Jie Gu

Duplex stainless steel is composed of equal amounts of austenite and ferrite, which has excellent corrosion resistance and strength. However, after the metal was welded…

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Abstract

Purpose

Duplex stainless steel is composed of equal amounts of austenite and ferrite, which has excellent corrosion resistance and strength. However, after the metal was welded, the ratio of austenite and ferrite in the joint is unbalanced, and secondary phase precipitates are produced, which is also an important cause of pitting corrosion in the joint.

Design/methodology/approach

This paper aims to study the mechanical and corrosion behavior of welded joints, by adjusting the welding parameters of laser hybrid welding, dual heat sources are used to weld 2205 duplex stainless steel. The two-phase content of different parts of the welded joint is measured to study the influence of the ratio of the two-phase on the mechanical and corrosion properties of the joint.

Findings

The ratio of austenite and ferrite in different welded joints has an obvious difference, and from top to bottom, the austenite content decreased gradually, and the ferrite content increased gradually. The harmful phases are precipitated in the middle and lower part of the joint. The strength of welded joints is slightly lower than that of base metal. At the same time, the fracture analysis shows that some ferrite phases are affected by the precipitate in the grain and produce quasi-cleavage fracture. The corrosion results show that the corrosion resistance of the welded joints is lower than that of the base metal, and the concentration of chloride ions affects the corrosion resistance.

Originality/value

In this paper, the authors use the influence of different welding processes on the two-phase ratio of the joint to further study the influence of the microstructure on the corrosion resistance and mechanical properties of the weld.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 19 August 2019

Hualiang Huang and Furong Bu

The purpose of this study is to provide a theoretical basis for the study of the galvanic corrosion mechanism of copper coupled silver-coating under a thin electrolyte…

Abstract

Purpose

The purpose of this study is to provide a theoretical basis for the study of the galvanic corrosion mechanism of copper coupled silver-coating under a thin electrolyte layer in electronic systems.

Design/methodology/approach

Electrochemical measurements and surface characterizations.

Findings

The results indicate that the potential difference between copper and silver electrodes first quickly increases, and then reaches a relatively stable and large value with the extension of the immersion time. With the significant increase in the cathode/anode area ratio in electronic systems, the area ratio effect obviously accelerates the corrosion of copper due to the remarkable promotion of the cathode process. For a large cathode/anode area ratio, the galvanic current density always maintains a large value and exhibits an increasing trend with the extension of the immersion time, which is attributed that the area ratio effect reduces the protection of corrosion products. For the same area of cathode and anode, the galvanic current density always maintains a small value with the extension of the immersion time due to a low galvanic effect and protective corrosion products.

Practical implications

This work provides some information for the establishment of reliably protective measures for electronic systems in service.

Social implications

This work not only provides some information for the establishment of reliably protective measures for electronic systems in service, but also provides a theoretical basis for the selection of metal materials in microelectronic systems.

Originality/value

This work provides not only a theoretical basis for the study of the galvanic corrosion mechanism of Cu/Ag under a thin electrolyte layer, but also provides some information for the establishment of reliably protective measures for electronic systems in service.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Abstract

Details

Globalization, Political Economy, Business and Society in Pandemic Times
Type: Book
ISBN: 978-1-80071-792-3

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