Zhenhan Yao, Xiaoping Zheng, Han Yuan and Jinlong Feng
Based on the error analysis, the authors proposed a new kind of high accuracy boundary element method (BEM) (HABEM), and for the large-scale problems, the fast algorithm, such as…
Abstract
Purpose
Based on the error analysis, the authors proposed a new kind of high accuracy boundary element method (BEM) (HABEM), and for the large-scale problems, the fast algorithm, such as adaptive cross approximation (ACA) with generalized minimal residual (GMRES) is introduced to develop the high performance BEM (HPBEM). It is found that for slender beams, the stress analysis using iterative solver GMRES will difficult to converge. For the analysis of slender beams and thin structures, to enhance the efficiency of GMRES solver becomes a key problem in the development of the HPBEM. The purpose of this paper is study on the preconditioning method to solve this convergence problem, and it is started from the 2D BE analysis of slender beams.
Design/methodology/approach
The conventional sparse approximate inverse (SAI) based on adjacent nodes is modified to that based on adjacent nodes along the boundary line. In addition, the authors proposed a dual node variable merging (DNVM) preprocessing for slender thin-plate beams. As benchmark problems, the pure bending of thin-plate beam and the local stress analysis (LSA) of real thin-plate cantilever beam are applied to verify the effect of these two preconditioning method.
Findings
For the LSA of real thin-plate cantilever beams, as GMRES (m) without preconditioning applied, it is difficult to converge provided the length to height ratio greater than 50. Even with the preconditioner SAI or DNVM, it is also difficult to obtain the converged results. For the slender real beams, the iteration of GMRES (m) with SAI or DNVM stopped at wrong deformation state, and the computation failed. By changing zero initial solution to the analytical displacement solution of conventional beam theory, GMRES (m) with SAI or DNVM will not be stopped at wrong deformation state, but the stress error is still difficult to converge. However, by GMRES (m) combined with both SAI and DNVM preconditioning, the computation efficiency enhanced significantly.
Originality/value
This paper presents two preconditioners: DNVM and a modified SAI based on adjacent nodes along the boundary line of slender thin-plate beam. In the LSA, by using GMRES (m) combined with both DNVM and SAI, the computation efficiency enhanced significantly. It provides a reference for the further development of the 3D HPBEM in the LSA of real beam, plate and shell structures.
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Ying Lv, Jinlong Feng, Guangbin Wang and Hua Li
This study aims to improve the maneuverability and stability of four-wheel chassis in a small paddy field; a front axle swing steering four-wheel chassis with optimal steering is…
Abstract
Purpose
This study aims to improve the maneuverability and stability of four-wheel chassis in a small paddy field; a front axle swing steering four-wheel chassis with optimal steering is designed.
Design/methodology/approach
When turning, the front inner wheel stops and the rear inner wheel is in the following state. The hydraulic drive system of the walking wheel adopts a driving mode in which two front-wheel motors are connected in series and two rear wheel motors in parallel. The chassis uses a combination of a gasoline engine with a water cooling system, a CVT continuously variable transmission and a hydraulic drive system to increase the control capability. The front axle rotary chassis adopts a step-less variable speed engine and a hydraulic control system to solve the hydraulic stability of the chassis in uphill and downhill conditions so as to effectively control the over-speed of the wheel-side drive motors. Through the quadratic orthogonal rotation combination design test, the mathematical models of uphill and downhill front-wheel pressures and test factors are established.
Findings
The results show that the chassis stability is optimal when the back pressure is 0.5 MPa, and the rotating slope is 4°. The uphill and downhill pressures of the front wheels are 2.38 MPa and 1.5 MPa, respectively.
Originality/value
The influence of external changes on the pressure of hydraulic motors is studied through experiments, which lays the foundation for further research.
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Yongming Wang, Jinlong Wang, Qi Zhou, Sai Feng and Xiaomin Wang
This study aims to address the issues of limited pipe diameter adaptability and low inspection efficiency of current pipeline inspection robots, a new type of pipeline inspection…
Abstract
Purpose
This study aims to address the issues of limited pipe diameter adaptability and low inspection efficiency of current pipeline inspection robots, a new type of pipeline inspection robot capable of adapting to various pipe diameters was designed.
Design/methodology/approach
The diameter-changing mechanism uses a multilink elastic telescopic structure consisting of telescopic rods, connecting rods and wheel frames, driven by a single motor with a helical drive scheme. A geometric model of the position relationships of the hinge points was established based on the two extreme positions of the diameter-changing mechanism.
Findings
A pipeline inspection robot was designed using a simple linkage agency, which significantly reduced the weight of the robot and enhanced its adaptive pipe diameter ability. The analysis determined that the robot could accommodate pipe diameters ranging from 332 mm to 438 mm. A static equilibrium equation was established for the robot in the hovering state, and the minimum pressing force of the wheels against the pipe wall was determined to be 36.68 N. After experimental testing, the robots could successfully pass a height of 15 mm, demonstrating the good obstacle capacity of the robot.
Practical implications
This paper explores and proposes a new type of multilink elastic telescopic variable diameter pipeline inspection robot, which has the characteristics of strong adaptability and flexible operation, which makes it more competitive in the field of pipeline inspection robots and has great potential market value.
Originality/value
The robot is characterized by the innovative design of a multilink elastic telescopic structure and the use of a single motor to drive the wheel for spiral motion. On the basis of reducing the weight of the robot, it has good pipeline adaptability, climbing ability and obstacle-crossing ability.
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Jinlong Li, Dongmei Li, Feng Zhou, Dapeng Feng, Yanqiu Xia and Weimin Liu
The aim of this paper was to inhibit the serious corrosion of conventional ionic liquids, a series of new ionic liquids (ILs) containing the triazole functionality, as the…
Abstract
Purpose
The aim of this paper was to inhibit the serious corrosion of conventional ionic liquids, a series of new ionic liquids (ILs) containing the triazole functionality, as the anti-corrosion groups were synthesized in this work.
Design/methodology/approach
It is well known that nitrogen and sulfur containing organic compounds have been traditionally used as corrosion inhibitors. Among them, triazole derivatives are most often used as corrosion inhibitors. To alleviate the corrosion of the ILs and further improve the anti-wear property, the authors prepared a series of imidazolium ILs modified with the triazole functionality in the present study.
Findings
The corrosion behavior of the ILs was evaluated with the iron disk corrosion test and their tribological properties were investigated on an Optimol SRV IV oscillating friction and wear tester at elevated temperatures. The results showed that the ILs with the triazole functionality could effectively reduce the corrosion and exhibit a smaller friction coefficient and wear volume than the unmodified counterpart. The ILs containing the triazole functionality can be used as the single component anti-corrosion base oils even at elevated temperatures.
Originality/value
The results showed that the ILs with the triazole functionality could effectively reduce the corrosion and exhibit a smaller friction coefficient and wear volume than the unmodified counterpart. The ILs containing the triazole functionality can be used as the single component anti-corrosion base oils even at elevated temperatures.
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Li Dong, Jinlong Chen and Weipeng Wu
This study examines how maturity mismatch, a specific type of financial structure of firms, affects corporate outward foreign direct investment (OFDI).
Abstract
Purpose
This study examines how maturity mismatch, a specific type of financial structure of firms, affects corporate outward foreign direct investment (OFDI).
Design/methodology/approach
Using the number of newly established foreign subsidiaries in a given year as firm-level OFDI and utilizing data from Chinese listed firms between 2007 and 2022, we employ a negative binomial regression model to examine the impact of corporate maturity mismatch on the OFDI. We also make efforts to ensure the robustness of the result, such as employing an exogenous policy to establish a difference-in-difference model.
Findings
The empirical result indicates that maturity mismatch inhibits firms' OFDI. Additional test shows that maturity mismatch increases firms' financing costs and reduces firms' research and development (R&D) investment and that the negative impact of maturity mismatch on OFDI is predominantly observed in firms with high financial constraints and low R&D intensity, indicating that maturity mismatch may affect firms' OFDI through the financing cost channel and the R&D investment channel.
Originality/value
Corporate maturity mismatch is common in China and similar emerging markets. However, research on the economic consequences of maturity mismatch, especially its impact on firms' overseas expansions, is rare. This study establishes the relationship between corporate maturity mismatch and OFDI, contributes to the literature on the relationship between financial factors and OFDI, and provides policy implications for emerging market countries.
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Jinlong Li, Dapeng Feng, Yongmin Liang, Yanqiu Xia and Weimin Liu
The purpose of this paper is to synthesize a series of cyclophosphazene derivatives with better tribological properties.
Abstract
Purpose
The purpose of this paper is to synthesize a series of cyclophosphazene derivatives with better tribological properties.
Design/methodology/approach
To improve the adsorptivity to substrate, a series of cyclophosphazene derivatives substituted with ionic liquids were synthesized. The lubricity characteristics of phosphazene derivatives were evaluated on an Optimol SRV IV oscillating friction and wear tester. Scanning electron microscope and X‐ray photoelectron spectroscope analyses were conducted to examine the morphology and chemical composition of the wear scars and the possible tribochemical changes involved in the friction process.
Findings
Alkoxycyclophosphazene derivatives substituted with ionic liquids synthesized in the present work show better antiwear ability and load‐carrying capacity in steel‐steel contacts. The density of ion pairs plays an important role on tribological properties.
Research limitations/implications
The paper deals with only a limited compounds and steel‐steel contacts. The paper works on the subject progressively to explore more combinations for better tribological properties.
Practical implications
All the cyclophosphazene derivatives present better tribological performance and could be used as base oils, such as hard disk surface lubricants.
Originality/value
Ionic liquids are introduced to cyclophosphazene derivatives in this paper. This is a new method to improve the tribological properties of cyclophosphazene derivatives.
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Fupeng Cheng, Jinglong Cui, Shuai Xu, Hongyu Wang, Pengchao Zhang and Juncai Sun
The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange…
Abstract
Purpose
The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated.
Design/methodology/approach
In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement.
Findings
The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests.
Originality/value
The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.
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Peiran Gao, Yeming Gong, Jinlong Zhang, Hongyi Mao and Shan Liu
The purpose of this paper is to explore the joint effects of different types of IT resources and top management support. Especially, the authors attempt to mainly examine a…
Abstract
Purpose
The purpose of this paper is to explore the joint effects of different types of IT resources and top management support. Especially, the authors attempt to mainly examine a negative synergy or substitution relationship between IT infrastructure resources and CEO support, and a positive synergy or complementary relationship between IT human resources and CEO support among the large-sized enterprises.
Design/methodology/approach
A research model that integrates IT infrastructure resources, IT human resources, CEO support and the degree of usage of IT for business objectives (i.e. IT business spanning capability) is developed. Based on a sample of 112 large-sized enterprises, partial least squares is used to analyze the research model.
Findings
Whereas the positive moderating role of CEO support in the effectiveness of IT human resources is insignificant, CEO support and IT infrastructure resources have a substitution relationship in predicting IT business spanning capability. Furthermore, the results can explain under which conditions IT infrastructure resources insignificantly or significantly affect IT business spanning capability in large-sized enterprises. Specially, IT infrastructure resources significantly affect IT business spanning capability only when CEO support is low. Thus, in the presence of high CEO support, IT executives in large-sized enterprises should prioritize developing highly effective IT resources, such as IT human resources.
Originality/value
This paper highlights the joint effects of two critical IT resource types (i.e. IT infrastructure and IT human resources) and CEO support in the IT assimilation process among the large-sized enterprises, ultimately contributing to information systems theories and practices.
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Shan Liu, Fan Xia, Jinlong Zhang and Lin Wang
Although crowdsourcing has gained significant attention and is being used by numerous companies to develop new products and solve practical issues, the performance of…
Abstract
Purpose
Although crowdsourcing has gained significant attention and is being used by numerous companies to develop new products and solve practical issues, the performance of crowdsourcing is not optimistic. The purpose of this paper is to develop a validated risk profile of crowdsourcing and investigate the relationships among different types of risks and those between risks and performance in crowdsourcing.
Design/methodology/approach
Based on the quantitative data collected from 136 crowdsourcing participants in China, two dimensions (i.e. social system and technical system risks) and five sub-dimensions (i.e. crowdsourcer, relationship, crowdsourcee, complexity, and requirement) of crowdsourcing risks are developed and validated. A theoretical model that integrates crowdsourcing risks and performance is developed. The technique of partial least squares is employed to assess the measurement model and test the hypotheses.
Findings
The empirical evidence determines the positive association of social system risks with technical system risks, which in turn negatively affect crowdsourcing performance. Specifically, relationship risk is positively affected by crowdsourcer and crowdsourcee risks, and these risks positively affect requirement and complexity risks. However, requirement and complexity risks negatively affect crowdsourcing performance.
Originality/value
This study explores the interrelationship between various risks and the relationship between risk and performance in the context of crowdsourcing by integrating risk-based view with socio-technical theory. Systematic but different risk mitigation strategies should be designed in crowdsourcing to manage risks and enhance performance.
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Bin Chen, Yuan Wang, Shaoqing Cui, Jiansheng Xiang, John-Paul Latham and Jinlong Fu
Accurate presentation of the rock microstructure is critical to the grain-scale analysis of rock deformation and failure in numerical modelling. 3D granite microstructure…
Abstract
Purpose
Accurate presentation of the rock microstructure is critical to the grain-scale analysis of rock deformation and failure in numerical modelling. 3D granite microstructure modelling has only been used in limited studies with the mineral pattern often remaining poorly constructed. In this study, the authors developed a new approach for generating 2D and 3D granite microstructure models from a 2D image by combining a heterogeneous material reconstruction method (simulated annealing method) with Voronoi tessellation.
Design/methodology/approach
More specifically, the stochastic information in the 2D image is first extracted using the two-point correlation function (TPCF). Then an initial 2D or 3D Voronoi diagram with a random distribution of the minerals is generated and optimised using a simulated annealing method until the corresponding TPCF is consistent with that in the 2D image. The generated microstructure model accurately inherits the stochastic information (e.g. volume fraction and mineral pattern) from the 2D image. Lastly, the authors compared the topological characteristics and mechanical properties of the 2D and 3D reconstructed microstructure models with the model obtained by direct mapping from the 2D image of a real rock sample.
Findings
The good agreements between the mapped and reconstructed models indicate the accuracy of the reconstructed microstructure models on topological characteristics and mechanical properties.
Originality/value
The newly developed reconstruction method successfully transfers the mineral pattern from a granite sample into the 2D and 3D Voronoi-based microstructure models ready for use in grain-scale modelling.