Lifang Wu, Zechao Liu, Yupeng Guan, Kejian Cui, Meng Jian, Yuanyuan Qin, Yandong Li, Feng Yang and Tianqin Yang
This paper aims to address the problem of uncertain product quality in digital light processing (DLP) three-dimensional (3D) printing, a scheme is proposed to qualitatively…
Abstract
Purpose
This paper aims to address the problem of uncertain product quality in digital light processing (DLP) three-dimensional (3D) printing, a scheme is proposed to qualitatively estimate whether a layer is printed with the qualified quality or not cured .
Design/methodology/approach
A thermochromic pigment whose color fades at 45°C is prepared as the indicator and it is mixed with the resin. A visual surveillance framework is proposed to monitor the visual variation in a period of the entire curing process. The exposure region is divided into 30 × 30 sub-regions; gray-level variation curves (curing curves) in all sub-regions are classified as normal or abnormal and a corresponding printing control strategy is designed to improve the percentage of qualified printed objects.
Findings
The temperature variation caused by the releasing reaction heat on the exposure surface is consistent in different regions under the homogenized light intensity. The temperature in depth begins to rise at different times. The temperature in the regions near the light source rises earlier, and that far from the light source rises later. Thus, the color of resin mixed with the thermochromic pigment fades gradually over a period of the entire solidification process. The color variation in the regions with defects of bubbles, insufficient material filling, etc., is much different from that in the normal curing regions.
Originality/value
A temperature-sensitive organic chromatic chemical pigment is prepared to present the visual variation over a period of the entire curing process. A novel 3D printing scheme with visual surveillance is proposed to monitor the layer-wise curing quality and to timely stop the possible unqualified printing resulted from bubbles, insufficient material filling, etc.
Details
Keywords
Wei Wei, Jun Chang, Qingjie Huang, Qiang Wang, Yuanyuan Liu and Zengguang Qin
As measurement results of optical gas sensors are constantly affected by the pressure of a target gas, approaches must be taken to modify the results. The purpose of this paper is…
Abstract
Purpose
As measurement results of optical gas sensors are constantly affected by the pressure of a target gas, approaches must be taken to modify the results. The purpose of this paper is to compare the traditional measurement method with the new measurement system. At the same time, measurement results of the two systems under different pressures are presented for comparison of the detection performance.
Design/methodology/approach
A theoretical model of line shape function and its impact on the measured results is presented, which is based on direct absorption and wavelength modulation spectroscopy (WMS) for gas concentration detection under different pressures. Methods of linear fitting and result modification have been illustrated and compared. A new testing system with the result modification method used for water vapor concentration detection under different pressures between 1 and 7 atm is applied. With an additional pressure sensor placed in the gas cell and calibration performed, relationships between the amplitude of the second harmonic and concentration of the target gas under different pressures can be obtained.
Findings
Amplitude detection can be used for concentration detection regardless of the change in pressure for the method of direct absorption. Although, WMS with second harmonic detection is not enough. Two methods are presented and compared with WMS under different pressures. Moreover, the result modification method shows better performance as computation is significantly reduced.
Originality/value
The comparison between linear fitting and the result modification method with WMS under different pressures is firstly presented. At the same time, a new testing system with better performance for water vapor concentration detection under different pressures is presented as well.
Details
Keywords
Yuanyuan Guo, Yilang Chen, Antonio Usai, Liang Wu and Wu Qin
Multinational small-to-medium-sized enterprises (SMEs) are increasingly participating in cross-border digital platforms – especially amid the COVID-19 pandemic. Accordingly…
Abstract
Purpose
Multinational small-to-medium-sized enterprises (SMEs) are increasingly participating in cross-border digital platforms – especially amid the COVID-19 pandemic. Accordingly, knowledge integration (KI) has become more and more important. In fact, it has been deemed by many as the key to organizational resilience. Given this burgeoning phenomenon, this study aims to explore a path for improving the resilience of multinational SMEs. Through this process, this study also finds a relationship between the KI processes associated with adopting global digital platforms and the resiliency of local–global businesses. Hence, in part, this paper also explores the effectiveness of all these mechanisms.
Design/methodology/approach
This study used the stepwise regression method in Stata 16.0 to analyze the direct effects of both horizontal and vertical KI processes on the resilience of local–global businesses. Additionally, t-tests were also used to compare the differences in coefficients between the mechanisms. The sample analyzed comprised data on multinational manufacturing SMEs in the Yangtze River Delta region of China who are using global digital platforms.
Findings
The KI processes of these firms, both horizontal and vertical, positively correlate to resilience. Horizontal KI processes more efficiently increase the resilience of global businesses, whereas vertical processes more efficiently increase the resilience of local businesses.
Originality/value
First, this study provides insights into how multinational SMEs can improve their resilience in a crisis. In addition to adding to the knowledge of KI processes, this expands the KM literature on pandemics. Second, by creating two KI processes based on global digital platforms and discussing their influence on resilience, this research deepens the understanding of affordance in the KM literature. Third, focusing on the KI research stream, the results shed light on how KI processes might occur and how firms develop their KI processes.
Details
Keywords
Zhaoju Qin, Chenheng Yuan, Yanpeng Yuan and Yuanyuan Huang
A free-piston engine (FPE) is an unconventional engine that abandons the crank system. This paper aims to focus on a numerical simulation for the lubricating characteristics of…
Abstract
Purpose
A free-piston engine (FPE) is an unconventional engine that abandons the crank system. This paper aims to focus on a numerical simulation for the lubricating characteristics of piston rings in a single-piston hydraulic free-piston engine (HFPE).
Design/methodology/approach
A time-based numerical simulation program was built using Matlab to define the piston motion of the new engine. And a lubrication mode of piston rings was built which is based on the gas flow equation, hydrodynamic lubrication equation and the asperity contact equation. The piston motion and the lubrication model are coupled, and then the finite difference method is used to obtain the piston rings lubrication performances of the FPE. Meanwhile, the lubrication characteristics of the new engine were compared with those of a corresponding conventional crankshaft-driven engine.
Findings
The study results indicate that compared with the traditional engine, the expansion stroke of the HFPE is longer, and the compression stroke is shorter. Lubrication oil film of the new engine is thicker than the traditional engine during the initial stage of compression stroke and the final stage of the power stroke. The average friction force and power of the hydraulic free piston engine are slightly lower than those of the traditional engine, but the peak friction power of the FPE is significantly greater than that of the traditional engine. With an increase in load, the friction loss power and friction loss efficiency decrease, and with a decrease in equivalence ratio, the friction power loss reduces, but the friction loss efficiency decreases first and then increases.
Research limitations/implications
In this paper, only qualitative analysis was performed on the tribological difference between conventional crankshaft engine and HFPE, instead of a quantitative one.
Practical implications
This paper contributes to the tribological design method of HFPE.
Social implications
No social implications are available now, as the HFPE is under the development phase. However, the authors are positive that their work will be commercialized in the near future.
Originality/value
The main originality of the paper can be introduced as follows: the lubrication and friction characteristics of the new engine (HFPE) were investigated and revealed, which have not been studied before; the effect of the HFPE’s special piston motion on the tribological characteristics was considered in the lubrication simulation. The results show that compared with the traditional crankshaft engine, the new engine shows a different lubrication performance because of its free piston motion.
Details
Keywords
Yi Wu, Jiahui Wu and Yuanyuan Cai
This study aims to investigate whether brand positioning strategies influence individuals’ conformity in product choices and identifies the mediator and boundary condition of this…
Abstract
Purpose
This study aims to investigate whether brand positioning strategies influence individuals’ conformity in product choices and identifies the mediator and boundary condition of this relationship.
Design/methodology/approach
To test the hypotheses, three experiments were conducted, with data collected using an online platform.
Findings
The results indicate that local (vs global) brand positioning promotes consumers’ tendencies to conform in their product choice. Furthermore, this effect is sequentially driven by their perceived similarity with such positioning and the feeling of social connectedness. The influence of local (vs global) brand positioning on consumer conformity diminishes among consumers with a focus on similarity.
Originality/value
This study expands the consumer conformity literature by identifying a new antecedent of consumer conformity. It also introduces a novel downstream consequence of local (vs global) brand positioning on consumer behavior and provides a broader theoretical basis for understanding the psychological connotations underlying local (vs global) brands.
Details
Keywords
Yuanyuan Yin, Shengfeng Qin and Ray Holland
The purpose of this paper is to investigate how to measure collaborative design performance and, in turn, improve the final design output during a design process, with a clear…
Abstract
Purpose
The purpose of this paper is to investigate how to measure collaborative design performance and, in turn, improve the final design output during a design process, with a clear objective to develop a design performance measurement (DPM) matrix to measure design project team members' design collaboration performances.
Design/methodology/approach
The methodology adopted in this research uses critical literature reviews, in‐depth focus group interviews and a questionnaire survey.
Findings
The main finding of this study is a DPM matrix that addresses five DPM indicators: efficiency, effectiveness, collaboration, management skill, and innovation, and 25 detailed DPM criteria. It was found that decision‐making efficiency is the most important DPM criterion for collaborative design efficiency; plus delivering to the brief for effectiveness; clear team goal/objectives for collaboration; decision‐making ability for management skill; and competitive advantage for innovation.
Research limitations/implications
As the present study was focused on exploring DPM during a design process, some key DPM criteria which are not measurable during a design development process were not included in this study. The proposed multi‐feedback approach for DPM matrix implementation needs to be validated in future research.
Practical implications
The DPM matrix can be applied to support a design manager in measuring and improving collaborative design performance during a design process, by reviewing and modifying collaborative design development, identifying the design team strengths and weaknesses, improving team communication, and suggesting suitable responsive actions.
Originality/value
The major contribution of this study is the investigation and development of a DPM matrix to measure collaborative design performance during a design process.
Details
Keywords
Junbang Lan, Yuanyuan Huo, IpKin Anthony Wong and Bocong Yuan
Drawing on the person–supervisor fit theory, this study aims to adopts a dyadic and relational approach to investigate the congruence between the leader’s and the follower’s…
Abstract
Purpose
Drawing on the person–supervisor fit theory, this study aims to adopts a dyadic and relational approach to investigate the congruence between the leader’s and the follower’s learning goal orientation (LGO) on their leader–member exchange (LMX) quality and the follower’s innovation.
Design/methodology/approach
The participants were 213 frontline employees and their 69 immediate supervisors from a large five-star hotel in China. The authors analyze the multiple-wave data using the cross-level polynomial regression approach.
Findings
The results show that when the levels of LGO between the leader and the follower are congruent, follower innovation and LMX are higher; when the levels of LGO between the leader and the follower are incongruent, it hinders LMX but benefits follower’s innovation.
Research limitations/implications
This study implies that personality congruence and incongruence can be equally important in creating positive work outcomes, enriching the theoretical understanding and practical implications for promoting LMX and follower innovation in hospitality industry.
Originality/value
Prior research has identified the importance of employees’ LGO in promoting innovation. However, the fit between employees’ and their leaders’ LGO has not been investigated.
Details
Keywords
Yuanyuan Chen, Xiufeng He, Jia Xu, Lin Guo, Yanyan Lu and Rongchun Zhang
As one of the world's most productive ecosystems, ecological land plays an important role in regional and global environments. Utilizing advanced optical and synthetic aperture…
Abstract
Purpose
As one of the world's most productive ecosystems, ecological land plays an important role in regional and global environments. Utilizing advanced optical and synthetic aperture radar (SAR) data for land cover/land use research becomes increasingly popular. This research aims to investigate the complementarity of fully polarimetric SAR and optical imaging for ecological land classification in the eastern coastal area of China.
Design/methodology/approach
Four polarimetric decomposition methods, namely, H/Alpha, Yamaguchi3, VanZyl3 and Krogager, were applied to Advanced Land Observing Satellite (ALOS) SAR image for scattering parameter extraction. These parameters were merged with ALOS optical parameters for subsequent classification using the object-based quick, unbiased, efficient statistical tree decision tree method.
Findings
The experimental results indicate that an improved classification performance was obtained in the decision level when merging the two data sources. In fact, unlike classification using only optical images, the proposed approach allowed to distinguish ecological land with similar spectrum but different scattering. Moreover, unlike classification using only polarimetric information, the integration of polarimetric and optical data allows to accurately distinguish reed from artemisia and sand from salt field and therefore achieve a detailed classification of the coastal area characteristics.
Originality/value
This research proposed an integrated classification method for coastal ecological land with polarimetric SAR and optical data. The object-based and decision-level fusion enables effective ecological land classification in coastal area was verified.
Details
Keywords
Chunling Liang, Ting Zou, Yan Zhang, Yuanyuan Li and Ping Wang
This paper aims to design a composite, aiming to improve the static puncture resistance through polyurethane impregnated treatment with five concentration gradients.
Abstract
Purpose
This paper aims to design a composite, aiming to improve the static puncture resistance through polyurethane impregnated treatment with five concentration gradients.
Design/methodology/approach
The relationship between polyurethane concentration, the number of polyester nonwovens, component fiber type (filament or staple) and the static puncture resistance is explored respectively and elaborately.
Findings
This study provides a new perspective to design flexible composites with better static puncture resistance, feasible preparation process as well as low cost.
Originality/value
The results show that the static puncture resistance of nonwovens impregnated by polyurethane is improved obviously. Meanwhile the puncture strength-T of nonwovens increases first and then decreases with the increase of the number of layers, and the maximum puncture strength-T is found at 20 layers. Moreover, the composite with filaments illustrates better mechanical resistance.
Details
Keywords
Guoqin Gao, Jun Sun and Yuanyuan Cao
This paper aims to solve the problems of the synchronization between branches and the uncertainties such as joint friction, load variation and external interference of a hybrid…
Abstract
Purpose
This paper aims to solve the problems of the synchronization between branches and the uncertainties such as joint friction, load variation and external interference of a hybrid mechanism. The controller is used to improve the synchronization and robustness of the hybrid mechanism system and achieve both finite time convergence and chattering-free sliding mode.
Design/methodology/approach
First, the dynamic model of hybrid mechanism containing lumped uncertainties is formulated by the Lagrange method, and a composite error based on coupling synchronization error and the end-effector tracking error is set up in the task space. Then, by combining the finite time super twisting sliding mode control algorithm, a composite error-based finite time super twisting sliding mode synchronous control law is designed to make the end-effector tracking error and coupling synchronization error achieve better tracking performance and convergence performance. Finally, the Lyapunov stability of the control law and the finite-time convergence of the composite error are proved theoretically.
Findings
To verify the effectiveness of the proposed control method, simulations and experiments for the prototype system of the hybrid mechanism are conducted. The results show that the proposed control method can achieve better tracking performance and convergence performance.
Originality/value
This is a new innovation for a hybrid mechanism containing lumped uncertainties to improve the robustness, convergence performance, tracking performance and synchronization of the system.