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Article
Publication date: 23 October 2018

Feng Liu, Shaoai Xie, Yan Wang, Jianjun Yu and Qinghua Meng

The titania (titanium dioxide) is one of the important functional additives in the photosensitive resin and encounters the problem of stabilization in the photosensitive resin for…

236

Abstract

Purpose

The titania (titanium dioxide) is one of the important functional additives in the photosensitive resin and encounters the problem of stabilization in the photosensitive resin for 3D printing. This study aims to achieve enhancement in stabilization by preparation of the polymerizable titania and in situ laser-induced crystallization during 3D printing.

Design/methodology/approach

A type of polymerizable titania (AAEM@TiO2) was designed and prepared from tetrabutyl titanate (TBT) and 2-(acetoacetoxy)ethyl methacrylate (AAEM) via the sol–gel process, which was characterized by Fourier-transform infrared (FTIR) spectra, ultraviolet–visible (UV-Vis) spectra, surface bonding efficiency (SBE) and settling height (H). AAEM acted on both bonding to the titania and polymerization with the monomer in resin for stabilization. The polymerizable titania could be converted to the pigmented titania by means of laser-induced crystallization. The photosensitive resin was then formulated on the basis of optimization and used in a stereolithography apparatus (SLA) for 3D printing.

Findings

The stabilization effect of AAEM on TiO2 was achieved and the mechanism of competition in the light-consuming reactions during photocuring was proposed. The ratio of nAAEM/nTBT in AAEM@TiO2, the concentration of AAEM@TiO2 and photoinitiator (PI) used in the photosensitive resin were optimized. The anatase crystal form was indicated by X-ray diffraction (XRD) and clustering of nanocrystals was revealed by scanning electron microscopy (SEM) after SLA 3D printing.

Originality/value

This investigation provides a novel method of pigmentation by preparation of the polymerizable titania and in situ laser-induced crystallization for SLA 3D printing.

Details

Rapid Prototyping Journal, vol. 24 no. 9
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 11 April 2021

Yifan Xu, Xiang Gu, Qinghua Meng, Bin Wang and Jun Fan

This paper aims to show a series of hydrogels with adjustable mechanical properties, which can be cured quickly with visible light. The hydrogel is prepared conveniently with…

458

Abstract

Purpose

This paper aims to show a series of hydrogels with adjustable mechanical properties, which can be cured quickly with visible light. The hydrogel is prepared conveniently with hydroxyethyl acrylate, cross-linker, gelatin and photoinitiator, and can be printed into certain 3D patterns with the direct ink write (DIW) 3D printer designed and developed by the research group.

Design/methodology/approach

In this paper, the authors designed a composite sensitization initiation system that is suitable for hydrogels. The concentration of photoinitiator, gelatin and cross-linker was studied to optimize the curing efficiency and adjust the mechanical properties. A DIW 3D printer was designed for the printing of hydrogel. Pre-gel solution was loaded into printer for printing into established models. The models were made and sliced with software.

Findings

The hydrogels can be cured efficiently with 405-nm visible light. While adding various content of gelatin and cross-linker, the mechanical properties of hydrogels show from soft and fragile (elastic modulus of 121.18 kPa and work of tension of 218.11 kJ·m−3) to rigid and tough (elastic modulus of 505.15 kPa and work of tension of 969.00 kJ·m−3). The hydrogels have high capacity of water absorption. With the DIW 3D printer, pre-gel hydrogel solution can be printed into objects with certain dimension.

Originality/value

In this work, a composite sensitization initiation system was designed, and fast curing hydrogels with adjustable mechanical properties had been prepared conveniently, which has high equilibrium water content and 3D printability with the DIW 3D printer.

Details

Rapid Prototyping Journal, vol. 27 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 3 July 2023

Zimin Li, Zilong Zhu, Jianqiu Wang, Meng Wang, Ting Hou, Qinghua Li and Pei Yu

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…

105

Abstract

Purpose

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.

Design/methodology/approach

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.

Findings

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.

Research limitations/implications

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.

Originality/value

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.

Details

Anti-Corrosion Methods and Materials, vol. 70 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 28 August 2024

Lu Yiling, Qinghua He, Ge Wang, Xiaopeng Deng and Jingxiao Zhang

Given the heavy pollution feature of the construction industry, construction corporations need to adopt an effective environmental governance strategy. The quality and quantity of…

53

Abstract

Purpose

Given the heavy pollution feature of the construction industry, construction corporations need to adopt an effective environmental governance strategy. The quality and quantity of environmental information disclosure (EID) implementation, as an essential part of a corporate environmental governance strategy, is impacted by the characteristics of the top management team (TMT). This paper aims to analyze the relationship between the demographic characteristics of the TMT (i.e. gender, age, tenure, educational level, and duality) and corporate EID.

Design/methodology/approach

Using data from listed construction corporations generated between 2014 to 2018 in China, this study employs the Tobit regression model to test the research hypotheses. Also, this study applies a novel analytical approach, necessary condition analysis (NCA), to conduct a series of additional tests.

Findings

The results reveal that tenure and educational level are significantly and positively related to EID, while gender, age, and duality in the executive role are not significantly related to EID. When considering the TMT size as a moderator, the TMT age is positively related to the corporate EID, and the size of the TMT acts as a moderator to weaken the positive effect of the TMT age on the EID. The NCA results show that TMT gender, age, tenure, and educational level are necessary when the levels of EID exceed 40%.

Originality/value

Our findings suggest that TMT characteristics have a relatively significant effect on corporate EID levels, which extends EID research to the construction industry. Corporate planners can endeavor to shape TMT characteristics to improve EID levels. The results of NCA provide insights into what TMT characteristics construction corporations need to satisfy in their pursuit of transparent EID, as well as the levels at which these characteristics are desired.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 29 November 2011

Qinghua Zhu, Jia Tina Du, Fei Meng, Kewen Wu and Xiaoling Sun

The purpose of this study is to develop an evaluation criteria system for search engines using the Delphi method and the analytic hierarchy process, and to conduct an empirical…

1180

Abstract

Purpose

The purpose of this study is to develop an evaluation criteria system for search engines using the Delphi method and the analytic hierarchy process, and to conduct an empirical study on Chinese search engines to verify it. This is because the evaluation criteria in current research rarely considers expert opinions and experience, and seldom calculates the weight of each criterion by quantitative methods.

Design/methodology/approach

Expert investigation of the web‐based Delphi method was employed to develop the evaluation criteria, and the analytic hierarchy process based on an exponential scale was adopted to calculate the weight of each criterion. An empirical study was designed to test the evaluation criteria system. A total of 12 study participants were invited to evaluate six popular Chinese search engines by means of e‐mail questionnaires. All the calculation processes were executed automatically by Java programming.

Findings

The indexing structure and search method were the core criteria for evaluating the search engines. Google (using simplified Chinese characters) achieved the best performance among the six typical Chinese search engines.

Originality/value

The criteria for search engine evaluation were determined and weighted by the web‐based Delphi method and the analytic hierarchy process based on an exponential scale.

Details

Online Information Review, vol. 35 no. 6
Type: Research Article
ISSN: 1468-4527

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Article
Publication date: 17 May 2024

Xiaoyan Chen, Weina Zhu, Yajiao Chen and Qinghua He

The development and evolution of stakeholder collaborative innovation in megaprojects is impacted by various influencing factors. The effect of influencing factors on…

263

Abstract

Purpose

The development and evolution of stakeholder collaborative innovation in megaprojects is impacted by various influencing factors. The effect of influencing factors on collaborative innovation performance (CIP) in megaprojects is not a simplistic linear relationship but an iterative and non-linear relationship that requires a dynamic perspective to analyze. Therefore, this paper adopts the system dynamic (SD) approach to investigate the dynamic and interactive relationships between the CIP and the influencing factors.

Design/methodology/approach

The study first develops a research framework with the system boundary of “CIP system – organizational collaboration subsystem – knowledge collaboration subsystem – strategic collaboration subsystem”. Then, the causal relationship model, the stock-flow model, and the mathematical equations were determined based on the literature review and the expert interviews. Finally, five performance improvement scenarios were designed according to the practice context of CIP in megaprojects, and simulations were performed using the Vensim PLE software to investigate the CIP from a dynamic perspective.

Findings

The findings reveal that the effect of different influencing factors on CIP grows non-linearly, with the cumulative effect becoming more pronounced as time advances. The incentive mechanism has the most significant effect, and the combined effect of multiple influencing factors has a highly significant facilitating effect on improving CIP. Strategic collaboration, organizational collaboration and knowledge collaboration are mutually conditional and reinforcing with each other, which ultimately promotes the improvement of CIP.

Originality/value

This study uncovers the inherent pattern and the interactive dynamic mechanism of factors for improving CIP in the context of megaprojects. It enriches the theoretical research in the area of collaborative innovation in megaprojects and provides practical management strategies for improving CIP.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 4 November 2021

Guotao Yang, Yue Wang, Huibin Chang and Qinghua Chen

This study examines the relative efficiencies of anti-poverty policies implemented in 28 Chinese provinces.

409

Abstract

Purpose

This study examines the relative efficiencies of anti-poverty policies implemented in 28 Chinese provinces.

Design/methodology/approach

This study uses meta-frontier undesirable dynamic two-stage data envelopment analysis. The authors divide the poverty reduction process into two stages: agricultural production and poverty reduction. Public expenditure is the input for the second stage, and the population below the poverty line is the undesirable output. The authors compute the efficiencies (overall efficiency, efficiency of each stage and the efficiencies of individual inputs and outputs) using meta-frontier analysis for the 28 provinces.

Findings

The results show that: (1) a significant imbalance exists between the eastern and western regions in terms of input-output efficiencies; (2) the poverty reduction stage generally fared better than the agricultural production stage did. In particular, most provinces saw increases in poverty reduction efficiencies between 2013 and 2017; (3) the place-based poverty relief policies introduced in recent years are effective at reducing the poverty rate and reaching the government-set goals and (4) while disposable income has increased steadily over the past few years, income inequality has been exacerbated.

Research limitations/implications

The results show that: (1) a significant imbalance exists between the eastern and western regions in terms of input-output efficiencies; (2) the poverty reduction stage generally fared better than the agricultural production stage did. In particular, most provinces saw increases in poverty reduction efficiencies between 2013 and 2017; (3) the place-based poverty relief policies introduced in recent years are effective at reducing the poverty rate and reaching the government-set goals and (4) while disposable income has increased steadily over the past few years, income inequality has exacerbated.

Originality/value

A large amount of attention and public resources are devoted to fighting poverty and associated market failures in China. The extant literature focuses either on the agricultural production itself or the relationship between human capital and productivity levels. Making use of recent developments of the DEA method, the authors propose a new framework for evaluating the efficiencies of the poverty reduction process. Such a framework has the advantage of giving researchers and policymakers a more detailed diagnosis with regard to the components in the endeavor to eliminate poverty and providing useful information for policymakers to optimize public funds use. Methodologically, the framework is flexible enough to be employed for future research in similar appraisals, at different geographic and scale aggregation levels, for public projects including but not limited to poverty reduction.

Details

China Agricultural Economic Review, vol. 14 no. 2
Type: Research Article
ISSN: 1756-137X

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Article
Publication date: 12 August 2019

Lei Guo, Lien Zhu, Lei Ma, Jian Zhang, QiuYu Meng, Zheng Jin, Meihua Liu and Kai Zhao

The purpose of this paper is to prepare a spherical modifier-modified activated carbon fiber of high specific capacitance intended for electrode materials of supercapacitor.

118

Abstract

Purpose

The purpose of this paper is to prepare a spherical modifier-modified activated carbon fiber of high specific capacitance intended for electrode materials of supercapacitor.

Design/methodology/approach

In this study, phenolic-based microspheres are taken as modifiers to prepare PAN-based fiber composites by electrospinning, pre-oxidation and carbonization. Pearl-chain structures appear in RFC/ACF composites, and pure polyacrylonitrile fibers show a dense network. The shape and cross-linking degree are large. After the addition of the phenolic-based microspheres, the composite material exhibits a layered pearlite chain structure with a large porosity, and the RFC/ACF composite material is derived because of the existence of a large number of bead chain structures in the composite material. The density increases, the volume declines and the mass after being assembled into a supercapacitor as a positive electrode material decreases. The specific surface area of RFC/ACF composites is increased as compared to pure fibers. The increase in specific surface area could facilitate the diffusion of electrolyte ions in the material. Owing to the large number of bead chains, plenty of pore channels are provided for the diffusion of electrolyte ions, which is conducive to enhancing the electrochemical performance of the composite and improving the RFC/ACF composite and the specific capacitance of the material. The methods of electrochemical testing on symmetric supercapacitors (as positive electrodes) are three-electrode cyclic voltammetry, alternating current impedance and cycle stability.

Findings

The specific capacitance value of the composite material was found to be 389.2 F/g, and the specific capacitance of the electrode operating at a higher current density of 20 mA/cm2 was 11.87 F/g (the amount of the microsphere modifier added was 0.3 g). Using this material as a positive electrode to assemble into asymmetrical supercapacitor, after 2,000 cycles, the specific capacitance retention rate was 87.46 per cent, indicating excellent cycle stability performance. This result can be attributed to the fact that the modifier embedded in the fiber changes the porosity between the fibers, while improving the utilization of the carbon fibers and making it easier for electrolyte ions to enter the interior of the composites, thereby increasing the capacitance of the composites.

Originality/value

The modified PAN-based activated carbon fibers in the study had high specific surface area and significantly high specific capacitance, which makes it applicable as an efficient and environment-friendly absorbent, as well as an advanced electrode material for supercapacitor.

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Article
Publication date: 22 December 2020

Tianyu Ma, Zhuofu Wang, Miroslaw Jan Skibniewski, Jiyong Ding, Ge Wang and Qinghua He

This research aims to analyzes how megaproject top managers engaged in stewardship behaviors. Studying megaprojects from the micro-foundations rooted in individual action and…

713

Abstract

Purpose

This research aims to analyzes how megaproject top managers engaged in stewardship behaviors. Studying megaprojects from the micro-foundations rooted in individual action and interaction, this research examines the gaps between literature and top managers' positive behavior to challenge the current theoretical underpinnings of megaproject governance research and practice.

Design/methodology/approach

An extensive literature review was performed in the initial phase. Then, a case study of South-to-North Water Diversion project was conducted based on following this project and on access to its top executives. Data was collected from multiple sources and analyzed by Nvivo (version 12). Further analysis was then carried out in two stages to identify megaproject stewardship behavior and related governance patterns.

Findings

Results show that stewardship behavior is prevalently existing and is possibly to be identified through psychological, situational, relational dimensions. Also, 16 factors have been found to describe the precise nature of megaproject stewardship behavior. Further explorative findings were discussed from three perspectives: possible theoretical development, self-actualization motivation and temporalities of megaprojects.

Originality/value

Building upon the ideas on how to extend steward theory towards project field, this research conducts a first exploration of stewardship behavior in megaprojects. This study contributes to complement the research into top-level organizational behavior in megaprojects, and it provides helpful implications for how to govern top managers in the following megaprojects with the cooperative spirit that can be valued by megaproject stakeholders.

Details

Engineering, Construction and Architectural Management, vol. 28 no. 9
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 16 May 2019

Qinghua He, Ting Wang, Albert P.C. Chan, Hanzhang Li and Yangxue Chen

The purpose of this paper is to review the existing literature on project success in academic journals, specifically within the context of construction engineering and management…

1303

Abstract

Purpose

The purpose of this paper is to review the existing literature on project success in academic journals, specifically within the context of construction engineering and management (CEM). It also aims to provide a holistic picture of existing research and to identify research implications in this specific area.

Design/methodology/approach

The paper is an extensive literature review of a total of 164 peer-reviewed journal papers between 2007 and 2017, using a mixed bibliographic and bibliometric method that considers annual circulation, institutional and regional contributions, author contributions, citations, categories of research methods and keywords networking.

Findings

There has been an increasing research interest in CEM project success. The largest number of published studies targets the developed regions, especially in Hong Kong, whereas the papers related to the developing economies remain weak. Questionnaire, interview and case study have comprised the main data collection methods, and descriptive data analysis was performed in most of the case/field studies. The subtopic related to the critical success factors (CSFs) is considered as the most popular in the keywords network in the targeted research area. Four implications, namely, megaproject success, project success in developing countries, relationships between CSFs and success outcomes, and the influence of human factors are highlighted in future research.

Originality/value

This paper departs from earlier research by using a mixed bibliographic and bibliometric method, especially facilitating to analyze and illustrate the interlinkages between keywords effectively. Additionally, it provides a clear picture of the existing literature on CEM project success, which contributes to insights for successful construction project management. Finally, the holistic analysis identifies gaps in the body of knowledge, revealing avenues for future research.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 8
Type: Research Article
ISSN: 0969-9988

Keywords

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