Yong Lu, Wei Zhang, Yuan‐yang Zhao, Zhi‐zhong Wang and Peng‐cheng Shu
The balanced vane pump is a common transmission component in hydraulic systems. Since the physicochemical properties of water and seawater are different from that of mineral oil…
Abstract
Purpose
The balanced vane pump is a common transmission component in hydraulic systems. Since the physicochemical properties of water and seawater are different from that of mineral oil, some problems can occur, for instance, poor lubrication, more leakage, and more corrosion. The paper aims to demonstrate the technical feasibility for the water hydraulic vane pump.
Design/methodology/approach
The material combinations were selected based on related research in literature. The volumetric efficiency and suction performance were measured in the current experiment. The relations between gap clearances and leakage flow, the contact and the friction forces between a vane tip and a cam contour were simulated based on mathematic models.
Findings
The soft‐hard material combinations in the prototype pump show preferable friction characteristics during tests. The axial clearances are the main channels of leakage flow. Pin type vane pump can reduce the contact force of the vane tip.
Originality/value
This paper outlines some key problems of the water hydraulic vane pump, such as the friction pair material,the structure, and the contact force of the vane tip by means of testing the basic performance of pump and mathematic model.
Details
Keywords
Rongrong Shi, Qiaoyi Yin, Yang Yuan, Fujun Lai and Xin (Robert) Luo
Based on signaling theory, this paper aims to explore the impact of supply chain transparency (SCT) on firms' bank loan (BL) and supply chain financing (SCF) in the context of…
Abstract
Purpose
Based on signaling theory, this paper aims to explore the impact of supply chain transparency (SCT) on firms' bank loan (BL) and supply chain financing (SCF) in the context of voluntary disclosure of supplier and customer lists.
Design/methodology/approach
Based on panel data collected from Chinese-listed firms between 2012 and 2021, fixed-effect models and a series of robustness checks are used to test the predictions.
Findings
First, improving SCT by disclosing major suppliers and customers promotes BL but inhibits SCF. Specifically, customer transparency (CT) is more influential in SCF than supplier transparency (ST). Second, supplier concentration (SC) weakens SCT’s positive impact on BL while reducing its negative impact on SCF. Third, customer concentration (CC) strengthens the positive impact of SCT on BL but intensifies its negative impact on SCF. Last, these findings are basically more pronounced in highly competitive industries.
Originality/value
This study contributes to the SCT literature by investigating the under-explored practice of supply chain list disclosure and revealing its dual impact on firms' access to financing offerings (i.e. BL and SCF) based on signaling theory. Additionally, it expands the understanding of the boundary conditions affecting the relationship between SCT and firm financing, focusing on supply chain concentration. Moreover, it advances signaling theory by exploring how financing providers interpret the SCT signal and enriches the understanding of BL and SCF antecedents from a supply chain perspective.
Details
Keywords
Yang Yuan and Haibin Duan
The purpose of this paper is to develop a novel active disturbance rejection attitude controller for quadrotors and propose a controller parameters identification approach to…
Abstract
Purpose
The purpose of this paper is to develop a novel active disturbance rejection attitude controller for quadrotors and propose a controller parameters identification approach to obtain better control results.
Design/methodology/approach
Aiming at the problem that quadrotor is susceptible to disturbance in outdoor flight, the improved active disturbance rejection control (IADRC) is applied to design attitude controller. To overcome the difficulty that adjusting the parameters of IADRC controller manually is complex, paired coevolution pigeon-inspired optimization (PCPIO) algorithm is used to optimize the control parameters.
Findings
The IADRC, where nonlinear state error feedback control law is replaced by non-singular fast terminal sliding mode control law and a third-order tracking differentiator is designed for second derivative of the state, has higher control accuracy and better robustness than ADRC. The improved PIO algorithm based on evolutionary mechanism, named PCPIO, is proposed. The optimal parameters of ADRC controller are found by PCPIO with the optimization criterion of integral of time-weighted absolute value of the error. The effectiveness of the proposed method is verified by a series of simulation experiments.
Practical implications
IADRC can improve the accuracy of attitude control of quadrotor and resist external interference more effectively. The proposed PCPIO algorithm can be easily applied to practice and can help the design of the quadrotor control system.
Originality/value
An improved active disturbance rejection controller is designed for quadrotor attitude control, and a hybrid model of PIO and evolution mechanism is proposed for parameters identification of the controller.
Details
Keywords
Qingyao Wan, Yang Yuan and Fujun Lai
The purpose of this paper is to explore how external pressures, internal capability and transaction attributes of logistics outsourcing synergically influence the extent of…
Abstract
Purpose
The purpose of this paper is to explore how external pressures, internal capability and transaction attributes of logistics outsourcing synergically influence the extent of asset-based and non-asset-based logistics outsourcing.
Design/methodology/approach
Based on the data surveyed from 250 manufacturing companies in China, this study employed fuzzy-set qualitative comparative analysis (fsQCA) to deduce multiple configurations for logistics outsourcing decisions.
Findings
The results suggest that asset-based logistics outsourcing is primarily driven by external imitation pressures or internal demands for logistics technologies, while non-asset-based logistics outsourcing is mainly driven by the demands for external management-based logistics services. Asset specificity plays a positive role in promoting both asset-based and non-asset-based logistics outsourcing. The requirement for third-party logistics (3PL) management capability depends on the outsourcing types and outsourcing causes.
Practical implications
This study provides guidance to practitioners for them to make outsourcing decisions. It suggests that asset-based logistics outsourcing is more appropriate when there are high external imitation pressures or more internal logistics demands, while non-asset-based logistics outsourcing should be used only when a firm needs management-based logistics services. Besides, 3PL users are suggested to outsource their logistics when their 3PL providers are required to make specific investments. In addition, managers should carefully evaluate firms’ capabilities in managing outsourcing relationships.
Originality/value
Previous studies largely ignored the interaction effects of a set of factors on logistics outsourcing decisions, and to date, little research empirically examined how outsourcing is driven in terms of different types of outsourcing. Drawing on the institutional theory, dynamic capability view, and transaction cost theory and overarching under the complexity theory, this study examines how institutional, organizational and transactional factors interplay with each other to influence different types of logistics outsourcing (i.e. asset based and non-asset based). Methodologically, the configural analysis (i.e. fsQCA) is applied to explore complex causal configurations that drive logistics outsourcing.
Details
Keywords
Peng Cai, Chengpeng Xu, Fei Zheng, Jingfu Song and Gai Zhao
The purpose of this paper is to investigate the effect of lanthana (La2O3) on the mechanical and tribological properties of polyimide (PI).
Abstract
Purpose
The purpose of this paper is to investigate the effect of lanthana (La2O3) on the mechanical and tribological properties of polyimide (PI).
Design/methodology/approach
The mechanical and tribological properties of PI nanocomposites filled with La2O3 were studied by molecular dynamic simulations to explore the deep mechanisms from an atomic or molecular view.
Findings
The results showed that the hardness of the PI matrix increased after La2O3 modification with a decrease of 72.4% nanoindentation depth. Besides, the friction coefficient of PI decreased by 72.2% after filling La2O3, and the shear deformation was largely reduced under the same conditions. The adsorption effect of La2O3 on the PI molecular, which reduced the atomic relative concentration, velocity, interaction with counterpart Fe layer and the temperature rise in the frictional interface, contributed to the improvement of the mechanical and tribological performance.
Originality/value
This study reveals the friction and wear mechanism of PI composites filled with rare earth oxide at the nanoscale.
Details
Keywords
Jeng-Haur Horng, Shin-Yuh Chern, Chi-Lin Li and Yang-Yuan Chen
This paper aims to investigate the temperature and wear properties of vertical ball screws and to discuss the surface design of ball screws in industrial applications.
Abstract
Purpose
This paper aims to investigate the temperature and wear properties of vertical ball screws and to discuss the surface design of ball screws in industrial applications.
Design/methodology/approach
The energy equation of the screw surface considering the frictional heat was established to verify the surface temperature of the ball screw. X-ray diffraction was used to examine the micro-contact temperature between the ball and screw. Debris size and density were examined to investigate wear properties of ball screws and to study the relationship of wear debris and temperature.
Findings
First, the main energy source for the surface temperature of high speed vertical ball screws is derived from friction force between ball and screw. Second, the temperature rise between the ball and screw has great relevance with wear debris concentration. Third, the surface temperature of the screw is higher than between the nut and ball for high speed vertical ball screws due to high convection heat transfer. The contact temperature of the nut near the flange is smaller than that of the nut away from the flange end due to the high contact load and thermal conduction. Finally, correlation of particle size and surface roughness value for vertical ball screws was established, and its effects on contact temperature were studied. The theoretical analysis and experiments will help to characterize the design and manufacture of vertical ball screws.
Originality/value
The surface temperature and micro-contact temperature analytical model were established to study the ball screw design. Based on the surface-particle micro-contact temperature balance, the optimal range of surface roughness was designed for vertical ball screws, considering the wear debris and micro-contact temperature.
Details
Keywords
The paper aims to explore the factors that influence the risk perception. The moderating roles of purchase experience and purchase involvement are also investigated.
Abstract
Purpose
The paper aims to explore the factors that influence the risk perception. The moderating roles of purchase experience and purchase involvement are also investigated.
Design/methodology/approach
The conceptual model is framed into the SOR (stimulus-organism-response) model, which was tested using data collected from the users of a leading group buying platform in China, with the help of LISREL.
Findings
The result indicates that both vendor- and intermediary-related factors exert negative yet significant influences on perceived risk. The relationships between vendor-related attributes and perceived risk are contingent on purchase involvement. The relationships between intermediary-related attributes and perceived risk are subject to purchase experience.
Originality/value
This study explores the moderating effects of purchase experience and purchase involvement based on the characteristics of group buying, demonstrating the differences from traditional online shopping.
Details
Keywords
Ziwen Gao, Steven F. Lehrer, Tian Xie and Xinyu Zhang
Motivated by empirical features that characterize cryptocurrency volatility data, the authors develop a forecasting strategy that can account for both model uncertainty and…
Abstract
Motivated by empirical features that characterize cryptocurrency volatility data, the authors develop a forecasting strategy that can account for both model uncertainty and heteroskedasticity of unknown form. The theoretical investigation establishes the asymptotic optimality of the proposed heteroskedastic model averaging heterogeneous autoregressive (H-MAHAR) estimator under mild conditions. The authors additionally examine the convergence rate of the estimated weights of the proposed H-MAHAR estimator. This analysis sheds new light on the asymptotic properties of the least squares model averaging estimator under alternative complicated data generating processes (DGPs). To examine the performance of the H-MAHAR estimator, the authors conduct an out-of-sample forecasting application involving 22 different cryptocurrency assets. The results emphasize the importance of accounting for both model uncertainty and heteroskedasticity in practice.
Details
Keywords
Emmanuel Posadas Paulino and Gladys Cuenca Esteban
The purpose of the study is to discover clusters or homogenous groups of work-from-home (WFH) Internet subscribers in the Philippines based on the attributes of speed, network…
Abstract
Purpose
The purpose of the study is to discover clusters or homogenous groups of work-from-home (WFH) Internet subscribers in the Philippines based on the attributes of speed, network quality, customer service, after-sales support, price, contract and value for money. Another objective is to determine if the formed clusters are related to the demographic profile.
Design/methodology/approach
A total of 275 internet subscribers from Metro Manila were surveyed. K-means cluster analysis using the Hartigan-Wong algorithm was performed on the data to generate the clusters.
Findings
Results generated four significant clusters, which were named service value expecters, average expecters, low expecters and high expecters. Most of the subscribers are under the high expecters, followed by the service value expecters. The age and income of the subscribers are the profile that can affect the formulation of clusters in the Internet service industry. Those people in the younger age groups can be seen as more demanding, while older people tend to be content with the Internet service. Counter-intuitively, people with higher income seem to be more easily satisfied with Internet service features, while those people with lower income seem to be more demanding. Educational attainment and the number of household members do not have a direct effect on the formulation of clusters of Internet subscribers.
Originality/value
This is the first study to use cluster analysis in identifying possible segments of WFH Internet subscribers based on Internet service attributes. Its value is the provision of market segments based on which can be the basis for formulating marketing strategies and policies for the telecommunications industry.
Details
Keywords
Nicola Cobelli and Emanuele Blasioli
The purpose of this study is to introduce new tools to develop a more precise and focused bibliometric analysis on the field of digitalization in healthcare management…
Abstract
Purpose
The purpose of this study is to introduce new tools to develop a more precise and focused bibliometric analysis on the field of digitalization in healthcare management. Furthermore, this study aims to provide an overview of the existing resources in healthcare management and education and other developing interdisciplinary fields.
Design/methodology/approach
This work uses bibliometric analysis to conduct a comprehensive review to map the use of the unified theory of acceptance and use of technology (UTAUT) and the unified theory of acceptance and use of technology 2 (UTAUT2) research models in healthcare academic studies. Bibliometric studies are considered an important tool to evaluate research studies and to gain a comprehensive view of the state of the art.
Findings
Although UTAUT dates to 2003, our bibliometric analysis reveals that only since 2016 has the model, together with UTAUT2 (2012), had relevant application in the literature. Nonetheless, studies have shown that UTAUT and UTAUT2 are particularly suitable for understanding the reasons that underlie the adoption and non-adoption choices of eHealth services. Further, this study highlights the lack of a multidisciplinary approach in the implementation of eHealth services. Equally significant is the fact that many studies have focused on the acceptance and the adoption of eHealth services by end users, whereas very few have focused on the level of acceptance of healthcare professionals.
Originality/value
To the best of the authors’ knowledge, this is the first study to conduct a bibliometric analysis of technology acceptance and adoption by using advanced tools that were conceived specifically for this purpose. In addition, the examination was not limited to a certain era and aimed to give a worldwide overview of eHealth service acceptance and adoption.