Yanfei Yang, Xiaobo Wang, Sen Mei, Xing Zhu, Shiqiang Chen, Peng Xiong, Zhihai Hu, Kun Xiong and Dong Song Yuan
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Abstract
Purpose
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Design/methodology/approach
BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope.
Findings
It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent.
Originality/value
This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.
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Keywords
Yiwen Li, Zhihai Dong, Junyan Miao, Huifang Liu, Aleksandr Babkin and Yunlong Chang
This paper aims to anticipate the possible development direction of WAAM. For large-scale and complex components, the material loss and cycle time of wire arc additive…
Abstract
Purpose
This paper aims to anticipate the possible development direction of WAAM. For large-scale and complex components, the material loss and cycle time of wire arc additive manufacturing (WAAM) are lower than those of conventional manufacturing. However, the high-precision WAAM currently requires longer cycle times for correcting dimensional errors. Therefore, new technologies need to be developed to achieve high-precision and high-efficiency WAAM.
Design/methodology/approach
This paper analyses the innovations in high-precision WAAM in the past five years from a mechanistic point of view.
Findings
Controlling heat to improve precision is an effective method. Methods of heat control include reducing the amount of heat entering the deposited interlayer or transferring the accumulated heat out of the interlayer in time. Based on this, an effective and highly precise WAAM is achievable in combination with multi-scale sensors and a complete expert system.
Originality/value
Therefore, a development direction for intelligent WAAM is proposed. Using the optimised process parameters based on machine learning, adjusting the parameters according to the sensors’ in-process feedback, achieving heat control and high precision manufacturing.
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Keywords
Shaoyi Liu, Song Xue, Peiyuan Lian, Jianlun Huang, Zhihai Wang, Lihao Ping and Congsi Wang
The conventional design method relies on a priori knowledge, which limits the rapid and efficient development of electronic packaging structures. The purpose of this study is to…
Abstract
Purpose
The conventional design method relies on a priori knowledge, which limits the rapid and efficient development of electronic packaging structures. The purpose of this study is to propose a hybrid method of data-driven inverse design, which couples adaptive surrogate model technology with optimization algorithm to to enable an efficient and accurate inverse design of electronic packaging structures.
Design/methodology/approach
The multisurrogate accumulative local error-based ensemble forward prediction model is proposed to predict the performance properties of the packaging structure. As the forward prediction model is adaptive, it can identify respond to sensitive regions of design space and sample more design points in those regions, getting the trade-off between accuracy and computation resources. In addition, the forward prediction model uses the average ensemble method to mitigate the accuracy degradation caused by poor individual surrogate performance. The Particle Swarm Optimization algorithm is then coupled with the forward prediction model for the inverse design of the electronic packaging structure.
Findings
Benchmark testing demonstrated the superior approximate performance of the proposed ensemble model. Two engineering cases have shown that using the proposed method for inverse design has significant computational savings while ensuring design accuracy. In addition, the proposed method is capable of outputting multiple structure parameters according to the expected performance and can design the packaging structure based on its extreme performance.
Originality/value
Because of its data-driven nature, the inverse design method proposed also has potential applications in other scientific fields related to optimization and inverse design.
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Keywords
Zhihai Yang, Ning Yin, Amin William Mugera and Yumeng Wang
This paper analysed survey data of 715 rice-producing households in China to assess the determinants of adoption of five mutually exclusive soil conservation practices (SCPs) and…
Abstract
Purpose
This paper analysed survey data of 715 rice-producing households in China to assess the determinants of adoption of five mutually exclusive soil conservation practices (SCPs) and their impact on rice yield and chemical fertiliser use.
Design/methodology/approach
The multinomial endogenous treatment effects model was used to account for selection bias and endogeneity arising from both observed and unobserved heterogeneity.
Findings
Farms that adopted SCPs as a package experienced an increase in rice yield and decrease in chemical fertiliser use. Adoption of SCPs as a package led to a 12.0% increase in yield and 15.2% decrease in chemical fertiliser use; these results have policy implications for the non-point source pollution control in the agricultural sector. In contrast, adoption of straw retention only significantly reduced yield by 4.9% and increased chemical fertiliser use by 18.1%.
Originality/value
The authors evaluate and compare multi-type of SCPs, such as straw retention, deep tillage and use of organic fertiliser, separately or in combination, and their impacts on smallholder farmers’ rice yield and chemical fertiliser usage.
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Junsong Jia, Zhihai Gong, Chundi Chen, Huiyong Jian and Dongming Xie
This paper aims to provide a typical example of accounting for the carbon dioxide equivalent (CO2e) in underdeveloped cities, especially for the Poyang Lake area in China. The…
Abstract
Purpose
This paper aims to provide a typical example of accounting for the carbon dioxide equivalent (CO2e) in underdeveloped cities, especially for the Poyang Lake area in China. The accounting can increase public understanding and trust in climate mitigation strategies by showing more detailed data.
Design/methodology/approach
The paper uses the “Global Protocol for Community-scale greenhouse gas emission inventories (GPC)” method, a worldwide comparable framework for calculating urban CO2e emission (CE). The empirical case is an underdeveloped city, Nanchang, in China.
Findings
The results show the total CE of Nanchang, containing the electricity CE of Scope 2, grew rapidly from 12.49 Mt in 1994 to 55.00 Mt in 2014, with the only recession caused by the global financial crisis in 2008. The biggest three contributors were industrial energy consumption, transportation and industrial processes, which contributed 44.71-72.06, 4.10-25.07 and 9.07-22.28 per cent, respectively, to the total CE. Almost always, more than 74.41 per cent of Nanchang’s CE was related to coal. When considering only the CEs from coal, oil and gas, these CEs per unit area of Nanchang were always greater than those of China and the world. Similarly, these CEs per gross domestic product of Nanchang were always bigger than those of the world. Thus, based on these conclusions, some specific countermeasures were recommended.
Originality/value
This paper argues that the CO2e accounting of underdeveloped cities by using the GPC framework should be promoted when designing climate mitigation policies. They can provide more scientific data to justify related countermeasures.
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Jianwen Yan, Kexin Zhang, Weiwei Zhu and Yu Fan
The purpose of this paper is to frame an empirical model with the priority of implementing soft critical successful factors (CSFs) of total quality management (TQM) in Chinese…
Abstract
Purpose
The purpose of this paper is to frame an empirical model with the priority of implementing soft critical successful factors (CSFs) of total quality management (TQM) in Chinese manufacturing companies.
Design/methodology/approach
In total, 23 hypotheses regarding the relationships among TQM factors and business results have been developed through literature review and are tested using the structural equation modelling (SEM). The data used in this study are collected from 228 manufacturing companies in the central area of China.
Findings
Of the 23 hypotheses, 11 were statistically significant, and according to the empirical results a conceptual framework complying to Chinese condition is constructed and discussed in the finding parts to group soft CSFs of TQM into different levels of importance.
Research limitations/implications
Researchers can use the framework to further study soft CSFs of TQM in detail, and extend it to explore their impact mechanism for a clearer and deeper understanding of the TQM.
Practical implications
The empirical framework for soft CSFs of TQM provides a new perspective for managers to implement the soft CSFs and optimise the quality management system of their manufacturing companies.
Originality/value
This research uses multiple, distinct indicators for each soft factor to test an elaborate SEM model of the relationships among them, according to the empirical results constructs a holistic framework classifying the importance level of soft CSFs of TQM, which is novel and subjected with Chinese condition and manufacturing characteristics.
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Khaled Mostafa, Mohamed Ramadan and Azza El-Sanabary
The purpose of this study is to investigate the authors' previously prepared and fully characterized poly (methacrylamide)-chitosan nanoparticles (CNPs) graft copolymer having…
Abstract
Purpose
The purpose of this study is to investigate the authors' previously prepared and fully characterized poly (methacrylamide)-chitosan nanoparticles (CNPs) graft copolymer having 50.2% graft yield with respect to flocculation efficiency for ferric laurate aqueous dispersions. This was done to compare the ability of the latter cheap, biodegradable and ecofriendly hybrid natural-synthetic polymeric substrate as a flocculant in comparison with higher cost, nonbiodegradable and harmful polyacrylamide as a well-known synthetic flocculant counterpart.
Design/methodology/approach
The graft copolymerization process was carried out at 450°Cfor 120 min using (1.0 g) CNPs, methacrylamide (1.5 g), 100 mmol/l potassium chromate and 80 mmol/l mandelic acid. Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis and specific viscosity were used to characterize and analyze the resultant copolymer. The flocculation efficiency was conferred in terms of transmittance % and weight removal %. The main factors influencing the flocculation process, such as flocculent dose, flocculation medium pH, stirring speed, flocculation temperature and grafting extent, were comprehensively discussed.
Findings
The flocculation efficiency of the prepared copolymers revealed the following findings: increased by increasing the flocculant dose, pH, temperature and stirring speed to a maximum values denoted at 30 ppm, 6.0, 30°C and 50 r/min, respectively, then decreased thereafter; increased by increasing the extent of grafting within the range studied; showed a comparable flocculation efficiency in comparison with polyacrylamide as a synthetic polymeric flocculent; and, finally, a preliminary bridging mechanism representing the attraction between the anionic suspended particles ferric laurate and cationic poly (MAam)-CNPs graft copolymer has been projected.
Originality/value
The advancement addressed here is undertaken with using the authors’ poly (MAam)-CNPs graft copolymers having different extent of grafting (a point which is not cited in the literature especially for the authors’ prepared copolymer) as a hybrid natural-synthetic polymeric substrate as a flocculant for ferric laurate aqueous dispersions in comparison with the high cost and nondegradable polyacrylamide synthetic flocculant.