Patrice Peyre, Neila Hfaiedh, Hongbin Song, Vincent Ji, Vincent Vignal, Wilfrid Seiler and Stephane Branly
The purpose of this paper is to conduct a comparative study of the surface modifications induced by two different lasers on a 2050‐T8 aluminum alloy, with a specific consideration…
Abstract
Purpose
The purpose of this paper is to conduct a comparative study of the surface modifications induced by two different lasers on a 2050‐T8 aluminum alloy, with a specific consideration of residual stress and work‐hardening levels.
Design/methodology/approach
Two lasers have been used for Laser shock peening (LSP) treatment in water‐confined regime: a Continuum Powerlite Plus laser, operating at 0.532 mm with 9 ns laser pulses, and near 1.5mm spot diameters; a new generation Gaia‐R Thales laser delivering 10 J‐10 ns impacts, with 4‐6mm homogeneous laser spots at 1.06 mm. Surface deformation, work‐hardening levels and residual stresses were analyzed for both LSP conditions. Residual stresses were compared with numerical simulations using a 3D finite element (FE) model, starting with the validation of surface deformations induced by a single laser impact.
Findings
Similar surface deformations and work‐hardening levels, but relatively lower residual stresses were obtained with the new large 4‐6 mm impact configuration. This was attributed to a reduced number of local cyclic loadings (2) compared with the small impact configuration (4). Additionally, more anisotropic stresses were obtained with small impacts. FE simulations using Johnson‐Cook's material' behavior were shown to simulate accurately surface deformations, but to overestimate maximum stress levels.
Research limitations/implications
This work should provide LSP workers a better understanding of the possible benefits from the different LSP configurations currently co‐existing: using small (<2 mm) impacts at high‐cadency rates or large ones (>4‐5 mm). Moreover, experimental results and simulated data had never been presented on 2050‐T8 Al alloy.
Originality/value
An experimental (and numerical) comparison using two distinct laser sources for LSP, has never been presented before. This preliminary work should help LSP workers to choose adequate sources.
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Xiaobing Fan, Bingli Pan, Hongyu Liu, Shuang Zhao, Xiaofan Ding, Haoyu Gao, Bing Han and Hongbin Liu
This paper aims to prepare an oil-impregnated porous polytetrafluoroethylene (PTFE) composite with advanced tribological properties using citric acid as a novel pore-forming agent.
Abstract
Purpose
This paper aims to prepare an oil-impregnated porous polytetrafluoroethylene (PTFE) composite with advanced tribological properties using citric acid as a novel pore-forming agent.
Design/methodology/approach
Citric acid (CA) was used to form pores in PTFE, and then oil-impregnated PTFE composites were prepared. The pore-forming efficiency of CA was evaluated. The possible mechanism of lubrication was proposed according to the tribological properties.
Findings
The results show CA is an efficient pore-forming agent and completely removed, and the porosity of the PTFE increases with the increase of the CA content. The oil-impregnated porous PTFE exhibits an excellent tribological performance, an increased wear resistance of 77.29% was realized in comparison with neat PTFE.
Originality/value
This study enhances understanding of the lubrication mechanism of oil-impregnated porous polymers and guides for their tribological applications.
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Xuening Fei, Yuanyuan Li, Shuai Li, Lingyun Cao, Dajie Xing, Bingyang Cheng, Meitong Li and Hongbin Zhao
This study aims to realize the multipurpose use of inorganic materials in adsorption treatment of pigment wastewater and preparation of core-modified Color Index Pigment Red 57:1…
Abstract
Purpose
This study aims to realize the multipurpose use of inorganic materials in adsorption treatment of pigment wastewater and preparation of core-modified Color Index Pigment Red 57:1 (C.I. Pigment Red 57:1, PR 57:1).
Design/methodology/approach
In this paper, the inorganic materials (sepiolite and SiO2·nH2O) were used in both PR 57:1 production wastewater treatment and its core-modification. The inorganic material firstly adsorbed 3-hydroxy-2-naphthoic acid (bon acid) in the pigment wastewater to reduce chemical oxygen demand. Then, the inorganic material adsorbed with bon acid was reused to prepare core-modified PR 57:1.
Findings
In the pigment wastewater adsorption experiment, it was found that under pH = 3, the adsorption percentage of bon acid by inorganic material can reached up to 46.00%. The pigment characterization results showed that the core-modified PR 57:1 had a core-shell structure. Under UV light irradiation for 1 h, the core-modified PR 57:1 prepared with sepiolite and SiO2·nH2O showed total color difference ΔE value of 1.43 and 2.05, respectively, which was lower than that of unmodified PR 57:1 (ΔE = 2.89). In addition, the transmittance of pigment water suspension test results showed that the core-modified PR 57:1 showed better water dispersibility.
Originality/value
This paper attempts to develop a synergistic strategy based on the multipurpose use of inorganic materials in adsorption treatment of pigment wastewater and preparation of core-modified PR 57:1.
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Hongbin Mu, Qingdong Yan and Wei Wei
Traditional prediction of braking characteristics of vehicular hydrodynamic retarders is commonly conducted based on braking characteristics model of closed working chamber…
Abstract
Purpose
Traditional prediction of braking characteristics of vehicular hydrodynamic retarders is commonly conducted based on braking characteristics model of closed working chamber, namely, closed working chamber model (CWCM). In CWCM, inlet and outlet oil pressures and braking torque are considered to be independent of inlet and outlet flow rates. However, inlet and outlet flow rates can affect internal and external braking characteristics under actual working conditions. This study aims to establish a more accurate braking characteristics model of a hydrodynamic retarder under full oil-charging condition, and then the influence of varying inlet and outlet flow rates on oil pressures and braking torque is investigated in this paper.
Design/methodology/approach
A full flow passage of working chamber in a hydrodynamic retarder with inlet and outlets was established, and the reliability of numerical model was analyzed and validated. Pressure rise was introduced to describe the variation of inlet and outlet oil pressures. Then, on the basis of the validation, the CWCM was proposed at different rotor rotational speeds. The inlet and outlet oil pressures and braking torque were numerically computed at different inlet and outlet flow rates with Full Factorial Design experimental method. The results obtained were involved into establishing the braking characteristics model of open working chamber, namely, open working chamber model (OWCM), combined with Radial basis function approximation model. The OWCM with different inlet and outlet flow rates was analyzed and compared with CWCM.
Findings
The results show that inlet and outlet flow rates have obvious influence on the variation of inlet and outlet oil pressures in OWCM compared with CWCM. The outlet A pressure rise significantly changes with the inlet and outlet A flow rates, while the pressure rise of outlet B is mainly affected by the outlet B flow rate.
Originality/value
This paper presents an OWCM of hydrodynamic retarders under full oil-charging condition. The model takes into account the impact of oil inflowing and outflowing from the working chamber, which can provide a more accurate prediction of braking characteristics of hydrodynamic retarders.
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Hongbin Huang, Ran Li and Ya Bai
The purpose of this paper is to study the influence of investor sentiment on the supply of trade credit, and further explores the difference of the effect of investor sentiment on…
Abstract
Purpose
The purpose of this paper is to study the influence of investor sentiment on the supply of trade credit, and further explores the difference of the effect of investor sentiment on the supply of trade credit in the environment of strong market competition and weak market competition.
Design/methodology/approach
The authors use panel estimation techniques to examine the impact of investor sentiment in the Chinese securities market on the supply of corporate trade credit.
Findings
This paper finds that investor sentiment has positive impact on trade credit through three channels of motivation, willingness and ability. At the same time, this paper finds that investor sentiment has stronger impact on enterprises in strong market competition than enterprises in weak market competition.
Research limitations/implications
This paper expands the research on the influence of virtual economy on the real economy, analyzes the difference of the influence of investor sentiment on the supply of trade credit under different market competition conditions.
Practical implications
The paper perfects the mechanism of trade credit decision-making at this stage, and provides more evidence for the virtual economy to act on the real economy.
Social implications
This paper provides a theoretical basis for the government functional departments to use the investor sentiment to play a positive role in trade credit to improve the market competition and guide the development of China’s capital market in the direction of rationalization and health.
Originality/value
In combination with market competition environment and industry characteristics, this paper investigates external irrational factors and studies how investor sentiment affects trade credit supply.
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Hongbin Li, Nina Sun and Zhihao Wang
This study aims to improve the positioning accuracy of a large-scale parallel pose alignment mechanism by calibration and error compensation.
Abstract
Purpose
This study aims to improve the positioning accuracy of a large-scale parallel pose alignment mechanism by calibration and error compensation.
Design/methodology/approach
The dynamic modelling of the parallel pose alignment mechanism is achieved using the Newton Euler method. Combined with a deformation compatibility analysis, the support force at the spherical hinge and the friction of the follow-up prismatic pair are calculated. The deformation of the moving platform in multi-pose space is analysed by the integral method, and a corresponding deformation model is established. Based on the calculated support force, friction and deformation, the deformation error is analysed. Combined with the calculated deformation error, kinematics calibration and positioning error compensation are carried out.
Findings
The simulation results show that the deviation of structural error identification is decreased from 3.03 × 10–1 mm to 6.8 × 10–2 mm. The experimental results show that the maximum pose errors after compensation are reduced from 2.77 mm to 6.5 × 10–1° to 3.9 × 10–1 mm and 3.7 × 10–1°, which verifies the effectiveness of the proposed method.
Originality/value
This method can be used in the field of aircraft assembly for the calibration and error compensation of a large-scale parallel pose alignment mechanism based on positioners.
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Junjian Lu, Hongbin Zhong and Fei Luo
The purpose of this research is as follows: DPP-BOH-PVA has been synthesized from 1,1′:3′,1″-terphenyl-5'-boronic acid (DPP-OH) and polyvinyl alcohol (PVA). The afterglow lifetime…
Abstract
Purpose
The purpose of this research is as follows: DPP-BOH-PVA has been synthesized from 1,1′:3′,1″-terphenyl-5'-boronic acid (DPP-OH) and polyvinyl alcohol (PVA). The afterglow lifetime of DPP-BOH-PVA was studied by changing contents of DPP-OH (1, 2 and 4 Wt.%). These films were characterized with Fourier transform infrared, X-ray diffraction as structural analysis and DSC as thermal analysis. Afterglow lifetimes were evaluated as time-resolved emission decay profile analysis. Fiber films of DPP-BOH-PVA-2-E have been prepared by electrospinning method with the diameter of 5 μm and afterglow life time of 2.1 s (@ 535 nm) under ambient conditions. Stimulus responsive properties with afterglow emission for fiber film were investigated.
Design/methodology/approach
During the synthesis of the polymer, modification was carried out using DPP-OH/PVA with a molar ratio of 1/4, under an alkalinity medium with ammonium hydroxide and with a temperature of 80°C.
Findings
XRD results indicate that DPP-BOH-PVA film had high crystallinity, which is crucial for preparing organic room temperature phosphorescence (RTP) materials.
Research limitations/implications
The reaction mixture must be stirred continuously. Temperature should be controlled to prevent the rapid evaporation of ammonium hydroxide.
Practical implications
This study provides technical information for the synthesis of multidimensional stimulation response RTP micron fiber thin film. The electrospinning technology may also promote the applications of the large areas of RTP films.
Social implications
This resin will be used for the multidimensional stimulation response RTP fiber thin film.
Originality/value
The diameter of fiber film of PP-BOH-PVA-2-E by electrospinning method was in the range of 5 μm, and its afterglow lifetime decayed to be 2.1 s.
Details
Keywords
Yi Xia, Yonglong Li, Hongbin Zang, Yanpian Mao, Haoran Wang and Jialong Li
A switching depth controller based on a variable buoyancy system (VBS) is proposed to improve the performance of small autonomous underwater vehicles (AUVs). First, the…
Abstract
Purpose
A switching depth controller based on a variable buoyancy system (VBS) is proposed to improve the performance of small autonomous underwater vehicles (AUVs). First, the requirements of VBS for small AUVs are analyzed. Second, a modular VBS with high extensibility and easy integration is proposed based on the concepts of generality and interchangeability. Subsequently, a depth-switching controller is proposed based on the modular VBS, which combines the best features of the linear active disturbance rejection controller and the nonlinear active disturbance rejection controller.
Design/methodology/approach
The controller design and endurance of tiny AUVs are challenging because of their low environmental adaptation, limited energy resources and nonlinear dynamics. Traditional and single linear controllers cannot solve these problems efficiently. Although the VBS can improve the endurance of AUVs, the current VBS is not extensible for small AUVs in terms of the differences in individuals and operating environments.
Findings
The switching controller’s performance was examined using simulation with water flow and external disturbances, and the controller’s performance was compared in pool experiments. The results show that switching controllers have greater effectiveness, disturbance rejection capability and robustness even in the face of various disturbances.
Practical implications
A high degree of standardization and integration of VBS significantly enhances the performance of small AUVs. This will help expand the market for small AUV applications.
Originality/value
This solution improves the extensibility of the VBS, making it easier to integrate into different models of small AUVs. The device enhances the endurance and maneuverability of the small AUVs by adjusting buoyancy and center of gravity for low-power hovering and pitch angle control.
Details
Keywords
Hongbin Huang, Yani Sun and Qingling Chu
The purpose of this paper is to investigate to what extent the amount, information source and the content of the microblog information disclosure of listed companies could impact…
Abstract
Purpose
The purpose of this paper is to investigate to what extent the amount, information source and the content of the microblog information disclosure of listed companies could impact on innovation from the perspective of financing constraints.
Design/methodology/approach
The propensity score matching (PSM) and two-stage least square (2SLS) are used in estimations to deal with the endogeneity problem.
Findings
Evidence shows that the amount of we-media information disclosure significantly drives the innovation of enterprises. The mechanism is that we-media information disclosure drives the innovation by easing the financing constraints and bringing funds to the R&D activities. Further research shows that only the original information can drive the innovation. In particular, the R&D information promotes the R&D input and innovation output more significantly.
Practical implications
The conclusion of this paper provides a reference for the listed companies to drive innovation with the help of we-media information disclosure, a new solution for the small and medium-sized listed companies in China which have difficulty in carrying out innovation activities due to financing constrains and also provides useful practical enlightenment for the government and the capital market regulatory authorities to issue relevant policies to regulate we-media information disclosure.
Originality/value
This paper introduces a new information disclosure channel--we-media into the research on influencing factors of innovation and discusses the influence of the amount, different sources and disclosure contents from we-media on enterprise innovation, which enriches the existing research on enterprise innovation influencing factors, providing a new perspective for driving enterprises to innovate.