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1 – 10 of over 1000Michele Chiumenti, Xin Lin, Miguel Cervera, Wei Lei, Yuxiang Zheng and Weidong Huang
This paper aims to address the numerical simulation of additive manufacturing (AM) processes. The numerical results are compared with the experimental campaign carried out at…
Abstract
Purpose
This paper aims to address the numerical simulation of additive manufacturing (AM) processes. The numerical results are compared with the experimental campaign carried out at State Key Laboratory of Solidification Processing laboratories, where a laser solid forming machine, also referred to as laser engineered net shaping, is used to fabricate metal parts directly from computer-aided design models. Ti-6Al-4V metal powder is injected into the molten pool created by a focused, high-energy laser beam and a layer of added material is sinterized according to the laser scanning pattern specified by the user.
Design/methodology/approach
The numerical model adopts an apropos finite element (FE) activation technology, which reproduces the same scanning pattern set for the numerical control system of the AM machine. This consists of a complex sequence of polylines, used to define the contour of the component, and hatches patterns to fill the inner section. The full sequence is given through the common layer interface format, a standard format for different manufacturing processes such as rapid prototyping, shape metal deposition or machining processes, among others. The result is a layer-by-layer metal deposition which can be used to build-up complex structures for components such as turbine blades, aircraft stiffeners, cooling systems or medical implants, among others.
Findings
Ad hoc FE framework for the numerical simulation of the AM process by metal deposition is introduced. Description of the calibration procedure adopted is presented.
Originality/value
The objectives of this paper are twofold: firstly, this work is intended to calibrate the software for the numerical simulation of the AM process, to achieve high accuracy. Secondly, the sensitivity of the numerical model to the process parameters and modeling data is analyzed.
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Haibin Geng, Jinglong Li, Jiangtao Xiong, Xin Lin, Dan Huang and Fusheng Zhang
As known, the wire and arc additive manufacture technique can achieve stable process control, which is represented with periodic surface waviness, when using empirical methods or…
Abstract
Purpose
As known, the wire and arc additive manufacture technique can achieve stable process control, which is represented with periodic surface waviness, when using empirical methods or feedback control system. But it is usually a tedious work to further reduce it using trial and error method. The purpose of this paper is to unveil the formation mechanism of surface waviness and develop a method to diminish it.
Design/methodology/approach
Two forming mechanisms, wetting and spreading and remelting, are unveiled by cross-section observation. A discriminant is established to differentiate which mechanism is valid to dominate the forming process under the given process parameters.
Findings
Finally, a theoretical method is developed to optimize surface waviness, even forming a smooth surface by establishing a matching relation between heat input (line energy) and materials input (the ratio of wire feed speed to travel speed).
Originality/value
Formation mechanisms are revealed by observing cross-section morphology. A discriminant is established to differentiate which mechanism is valid to dominate the forming process under the given process parameters. A mathematical model is developed to optimize surface waviness, even forming a smooth surface through establishing a matching relation between heat input (line energy) and materials input (the ratio of wire feed speed to travel speed).
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Qian Hu, Xin Lin, Shuguang Han and Lei Li
The purpose of this paper is to explore different tagging behaviours between Chinese and Americans by analysing the movie tags, and explore the feasibility of applying cultural…
Abstract
Purpose
The purpose of this paper is to explore different tagging behaviours between Chinese and Americans by analysing the movie tags, and explore the feasibility of applying cultural differences to tag recommendations.
Design/methodology/approach
This paper introduced hypotheses based on several well-established psychological theories and tested them with social tags for the same movies generated by Chinese and Americans. And to prove the utility of the cultural factor consideration, this paper conducted a cross-cultural tag recommendation experiment.
Findings
The results show that compared with Americans, Chinese users tend to add more tags about movies’ background information (e.g. release year) and global contextual characteristics (e.g. genre); they also prefer to add tags about production countries and factual tags, and cultural factors can be applied for recommending more accurate tags.
Research limitations/implications
Other reasons for tagging differences beyond cultural factors have not be explored. Tags for some sample movies in MovieLens might be unstable, as they had been tagged by a small scale of users; as a result, the tags’ type distribution might be influenced.
Practical implications
The results and conclusion of this study will be beneficial for the cross-cultural applications of social tags and mining users’ interests based on tags.
Originality/value
This paper provided a deeper investigation of the cross-cultural effect in people’s social tagging behaviours from cognitive perspective, and an empirical analysis has been performed to explore proper approaches of incorporating cultural differences for tag recommendation.
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Yingjie Zhang, Wentao Yan, Geok Soon Hong, Jerry Fuh Hsi Fuh, Di Wang, Xin Lin and Dongsen Ye
This study aims to develop a data fusion method for powder-bed fusion (PBF) process monitoring based on process image information. The data fusion method can help improve process…
Abstract
Purpose
This study aims to develop a data fusion method for powder-bed fusion (PBF) process monitoring based on process image information. The data fusion method can help improve process condition identification performance, which can provide guidance for further PBF process monitoring and control system development.
Design/methodology/approach
Design of reliable process monitoring systems is an essential approach to solve PBF built quality. A data fusion framework based on support vector machine (SVM), convolutional neural network (CNN) and Dempster-Shafer (D-S) evidence theory are proposed in the study. The process images which include the information of melt pool, plume and spatters were acquired by a high-speed camera. The features were extracted based on an appropriate image processing method. The three feature vectors corresponding to the three objects, respectively, were used as the inputs of SVM classifiers for process condition identification. Moreover, raw images were also used as the input of a CNN classifier for process condition identification. Then, the information fusion of the three SVM classifiers and the CNN classifier by an improved D-S evidence theory was studied.
Findings
The results demonstrate that the sensitivity of information sources is different for different condition identification. The feature fusion based on D-S evidence theory can improve the classification performance, with feature fusion and classifier fusion, the accuracy of condition identification is improved more than 20%.
Originality/value
An improved D-S evidence theory is proposed for PBF process data fusion monitoring, which is promising for the development of reliable PBF process monitoring systems.
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Zhi Zhou, Xiangming Mu and Xin Lin
This paper aims to propose a novel approach to constructing an economic taxonomy that demonstrates the complex relationships between firms, which are not fully revealed by…
Abstract
Purpose
This paper aims to propose a novel approach to constructing an economic taxonomy that demonstrates the complex relationships between firms, which are not fully revealed by traditional industry classification systems such as the NAICS or ICB.
Design/methodology/approach
Based on narrative economic theory, data from CNBC news reports between 01/01/2019 and 03/27/2019 regarding four selected firms, namely, Walmart, Amazon, Netflix and Boeing, were analyzed and coded as the basis to guide the construction of a firm-to-firm relationship taxonomy.
Findings
The relationships between firms are more complex than the simple relationships defined by the traditional classification systems with yes or no in terms of production process (NAICS) or major profit resource (ICB). Based on the sample firms, the authors proposed a four-layer hierarchical taxonomy framework that quantitatively reveals the inherent contradictory relationships between firms, which the authors defined as competition vs consistency. The proposed taxonomy framework is sufficiently flexible to accommodate complex relationships between firms, and it is also adaptable to new information. Under both the competition and consistency categories in the taxonomy model, more detailed subcategories are further coded into two more layers quantitatively to represent the firms' nuanced relationships.
Originality/value
This study provides a novel atheoretical approach to reveal complex firm relationships utilizing narrative text data gathered from news media. The framework of the firm relationship taxonomy constructed in this study provides an alternative and supplementary approach to the classical industry classification systems that can quantitatively specify comprehensive and dynamic connections between firms.
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Owing to the importance of the investment behavior in China, the purpose of this paper is to find the influence of executive network and government governance on investment…
Abstract
Purpose
Owing to the importance of the investment behavior in China, the purpose of this paper is to find the influence of executive network and government governance on investment efficiency.
Design/methodology/approach
The paper use China’s listed companies as sample to make an investment efficiency determinant model.
Findings
In this article, the authors find that larger executive network and higher government governance will lead to more corporate investment efficient. Furthermore, the informal institution – executive network, is not only an effective way to alleviate financing constraints, but also can solve underinvestment problem. While the improvement of local government governance can provide institutional protection, it will also be more conducive to restrain overinvestment behavior.
Research limitations/implications
The authors have not explored conduction path. Especially, the authors have not examined whether information spillover effect or the release of resources constraints in executive network plays a more important role to ease investment insufficient.
Originality/value
Under the Chinese circumstance, relationship governance can not only promote companies to improve investment efficiency, but also provide an important guarantee for sustained macroeconomic growth.
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Xian Xin, Tun Lin, Xiaoyun Liu, Guanghua Wan and Yongsheng Zhang
The impacts of climate change on agricultural production in the People’s Republic of China’s (PRC) are significant, and differ across regions and crops. The substantial regional…
Abstract
Purpose
The impacts of climate change on agricultural production in the People’s Republic of China’s (PRC) are significant, and differ across regions and crops. The substantial regional differences will induce changes in agricultural interregional trade pattern. The purpose of this paper is to investigate the climate change impacts on China’s agricultural interregional trade pattern.
Design/methodology/approach
The paper will use the computable general equilibrium (CGE) model to assess the impacts of climate change on the PRC’s agricultural interregional trade flows. The CGE model consists of seven Chinese regions and the rest of the world and six commodities.
Findings
The results indicate that northwest, south, central, and northeast PRC will see increases in the outflows of agricultural products in 2030 and 2050. Conversely, outflows from east, north, and southwest PRC will decrease. Agricultural products handling and transportation facilities need to be repositioned to address the changes in agricultural trade flows.
Originality/value
Studies on the impacts of climate change on the PRC’s agriculture have been increasing. To the best of our knowledge, however, no previous studies have assessed the impacts of climate change on the PRC’s agricultural interregional trade flows. This paper aims to fill this gap in the literature.
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Jian‐Qiang Hu, Xin‐Lin Wang, Ge‐Lin Dai, Yi‐Wei Fei, Xian‐Yong Wei and Zhi‐Min Zong
Molybdenum dithiocarbamate (MoDDC) has good antiwear and friction‐reducing properties in lubricants, and can be protected against thermo‐oxidative degradation. However…
Abstract
Purpose
Molybdenum dithiocarbamate (MoDDC) has good antiwear and friction‐reducing properties in lubricants, and can be protected against thermo‐oxidative degradation. However, MoDDC‐containing lubricants may lose their ability to reduce friction over time, which may result from its concentration in oils below a critical concentration owing to oxidative degradation of MoDDC. Thus, in order to enhance the durability of the low friction performance of MoDDC, the paper aims to investigate good synergistic antioxidants with MoDDC.
Design/methodology/approach
The antioxidation properties of molybdenum dialkyldithiocarbamate (M 807) – and p,p‐dioctyldiphenylalmine (V 81) – or mixed octylated and butylated diphenylalmines (V 961)‐containing poly‐α‐olefin (PAO)‐derived lubricants were evaluated by differential scanning calorimetry (DSC) and modified penn state micro‐oxidation test (PMOT). DSC test measures incipient oxidation temperature (OT) and oxidation induction time (IT) of the lubricant at high temperatures and the oxidation stability of oil weight loss is measured by PMOT. Moreover, the oxidized samples were analyzed by Fourier transform infrared (FTIR) and electron spin resonance (ESR).
Findings
A DSC test shows that OT and IT of V 81‐ or V 961‐containing PAO were improved significantly by M 807 addition. A PMOT indicates that when combining with V 81 antioxidants, M 807 can also effectively reduce the increase in weight loss of PAO and deposits formed in oils. These results suggest that the M 807 shows a good antioxidative synergism with alkylated diphenylamine antioxidants. In addition, FTIR results from a PMOT confirm that the addition of M 807 can significantly enhance the oxidation IT of oils containing V 81 and inhibit formation of oxidation products including carbonyl bonds or hydroxyl group. ESR analysis from a PMOT indicates that M 807 may form stable radicals with arylamine by the coordination effect.
Originality/value
This paper provides simple and quick methods to evaluate synergistic antioxidation properties between different types of additives, and a mechanism of the inhibition involving a synergy was proposed. They can offer practical help in industrial applications and to an individual starting out on an academic career.
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This chapter examines the development of accounting thought and practices in China with the purpose of illustrating its relevance to current accounting policies and practices. The…
Abstract
This chapter examines the development of accounting thought and practices in China with the purpose of illustrating its relevance to current accounting policies and practices. The review indicates that changes in accounting in China did not usually occur completely and easily. Over the past three decades, while Chinese accounting has gradually moved toward the Anglo-American model, convergence has presented unique features in China. For example, the review suggests that the accounting reforms in China have been heavily government-driven and that uniform accounting systems still remain. Chinese regulators maintain a cautious attitude toward the application of fair value and professional judgment, which are essentially the center of the Anglo-American accounting system. Furthermore, Chinese accounting regulators have a different view of business combinations from the IASB and have developed alternative accounting methods for those transactions. China’s departure from IFRS reflects its politico-economic context and essentially challenges the IASB’s goal of achieving international accounting convergence. China’s approach to internationally acceptable practices is likely to have implications for the effectiveness of the imported ideas.
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Yin Pan and Tiejun Zhou
Due to the rapid urbanization in China, the living environment in urban areas improves considerably, while that in rural settlements does not improve remarkably, or even worsens…
Abstract
Due to the rapid urbanization in China, the living environment in urban areas improves considerably, while that in rural settlements does not improve remarkably, or even worsens. The purpose of the research is to propose an organizational approach to the improvement of the living environment in the poverty-stricken rural settlements and an architectural design pattern under a variety of requirements in the context of China’s rapid urbanization and socio-economic development in the redevelopment of rural settlements in Yongsheng Village, Lizhuang Town, Yibin City of Sichuan Province in Southwest China. In this redevelopment project, the architects, as the important third party, are not just architects in the traditional sense in that they are involved in the organizational process and architectural design throughout the whole project. The redevelopment project has been completed, and is aimed at providing a scientific redevelopment model and a design method for other rural residents by guiding them in the improvement of their living environment under a variety of restrictions.
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