Man Zhang, Liangping Xia, Suihu Dang, Lifang Shi, Axiu Cao and Chunlei Du
The pressure sensors can convert external pressure or mechanical deformation into electrical power and signal, which cannot only detect pressure or strain changes but also harvest…
Abstract
Purpose
The pressure sensors can convert external pressure or mechanical deformation into electrical power and signal, which cannot only detect pressure or strain changes but also harvest energy as a self-powered sensor. This study aims to develop a self-powered flexible pressure sensor based on regular nanopatterned polymer films.
Design/methodology/approach
In this paper, the self-powered flexible pressure sensor is mainly composed of two nanopatterned polymer films and one conductive electrode layer between them, which is a sandwich structure. The regular nanostructures increase the film roughness and contact area to enhance the friction effect. To enhance the performance of the pressure sensor, different nanostructures on soft polymer sensitive layers are fabricated using UV nanoimprint lithography to generate more triboelectric charges.
Findings
Finally, the self-powered flexible pressure sensor is prepared, which consists of sub-200 nm resolution regular nanostructures on the surface of the elastic layer and an indium tin oxide electrode thin film. By converting the friction mechanical energy into electrical power, a maximum power of 423.8 mW/m2 and the sensitivity of 0.8 V/kPa at a frequency of 5 Hz are obtained, which proves the excellent sensing performance of the sensor.
Originality/value
The acquired electrical power and pressure signal by the sensor would be processed in the signal process circuit, which is capable of immediately and sustainably driving the highly integrated self-powered sensor system. Results of the experiments show that this new pressure sensor is a potential method for personal pressure monitoring, featured as being wearable, cost-effective, non-invasive and user-friendly.
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Ye Su, Ye Yutang, Xie Yu, Yi Maoli, Zhang Jing, Luo Ying and Du Chunlei
– This paper aims to solve the issue of target positioning in auto stiffener bonder (ASB) systems for flexible printed circuits.
Abstract
Purpose
This paper aims to solve the issue of target positioning in auto stiffener bonder (ASB) systems for flexible printed circuits.
Design/methodology/approach
The proposed approach uses Phong’s bidirectional reflectance distribution function (BRDF) model to simulate the reflection of light off a target in ASB systems to predict the current pose of the target based on image brightness, update the template, decrease the initial errors in the template and narrow down the search range.
Findings
The experimental results indicate that the proposed approach can predict the inclination angle of the target with precision, presenting angle prediction errors of less than three degrees. Furthermore, with larger inclined angles, the overall matching errors were less than 1.5 pixels. Comparisons with the unmodified matching algorithm revealed that the proposed approach resulted in 65 per cent less calculation time for the algorithm and 14 per cent higher overall work efficiency in the ASB system.
Originality/value
The edge-based perspective shape matching algorithm was modified using the Phong BRDF model and enhanced algorithm efficiency with the target pose prediction method while ensuring the precision and robustness of the system. The proposed approach has high potential value and can be expanded to recognition systems for objects with varying inclination angles and highly reflective surfaces.
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Chunlei Shao, Zhongyuan Zhang and Jianfeng Zhou
The purpose of this paper is to accurately predict the cavitation performance of a cryogenic pump and reveal the influence of the inlet pressure, the surface roughness and the…
Abstract
Purpose
The purpose of this paper is to accurately predict the cavitation performance of a cryogenic pump and reveal the influence of the inlet pressure, the surface roughness and the flow rate on the cavitation performance.
Design/methodology/approach
Firstly, the Zwart cavitation model was modified by considering the thermodynamic effect. Secondly, the feasibility of the modified model was validated by the cavitation test of a hydrofoil. Thirdly, the effects of the inlet pressure, the surface roughness and the flow rate on cavitation flow in the cryogenic pump were studied by using the modified cavitation model.
Findings
The modified cavitation model can predict the cavitation performance of the cryogenic pump more accurately than the Zwart cavitation model. The thermodynamic effect inhibits cavitation development to a certain extent. The higher the vapor volume fraction, the lower the pressure and the lower the temperature. At the initial stage of the cavitation, the head increases first and then decreases with the increase of the roughness. When the cavitation develops to a certain degree, the head decreases with the increase of the roughness. With the decrease of the flow rate, the hydraulic loss increases and the cavitation at the impeller intensifies.
Originality/value
A cavitation model considering the thermodynamic effect is proposed. The mechanism of the influence of the roughness on the performance of the cryogenic pump is revealed from two aspects. Taking the hydraulic loss as a bridge, the relationships among flow rates, vapor volume fractions, streamlines, temperatures and pressures are established.
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Zhimin Cao, Wenjun Zong, Junjie Zhang, Chunlei He, Jiaohu Huang, Wei Liu and Zhiyong Wei
This paper aims to reveal the tribochemical reaction mechanism on the nano-cutting interface between HMX crystal and diamond tool.
Abstract
Purpose
This paper aims to reveal the tribochemical reaction mechanism on the nano-cutting interface between HMX crystal and diamond tool.
Design/methodology/approach
Molecular dynamics simulation of HMX crystal nano-cutting by the reactive force field is carried out in this paper. The affinity of activated atoms and friction damage at the different interface have been well identified by comparing two cutting systems with diamond tool or indenter. The analyses of reaction kinetics, decomposition products and reaction pathways are performed to reveal the underlying atomistic origins of tribocatalytic reaction on the nano-cutting interface.
Findings
The HMX crystals only undergo damage and removal in the indenter cutting, while they appear to accelerate thermal decomposition in the diamond cutting. the C-O affinity is proved to be the intrinsic reason of the tribocatalytic reaction of the HMX-diamond cutting system. The reaction activation energy of the HMX crystals in the diamond cutting system is lower, resulting in a rapid increase in the decomposition degree. The free O atoms can induce the asymmetric ring-opening mode and change the decomposition pathways, which is the underlying atomistic origins of the thermal stability of the HMX-diamond cutting system.
Originality/value
This paper describes a method for analyzing the tribochemical behavior of HMX and diamond, which is beneficial to study the thermal stability in the nano-cutting of HMX.
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The aim of this study was to investigate the impact of the transactive memory system (TMS) on green innovation and examine the mediation role of the social network at all…
Abstract
Purpose
The aim of this study was to investigate the impact of the transactive memory system (TMS) on green innovation and examine the mediation role of the social network at all hierarchical levels.
Design/methodology/approach
Three hypotheses were examined by performing regression analyses on survey data from manufacturing firms in China. Especially, the nested sets of data from 389 individual observations nested in 53 work teams, including individual level and collective level have been investigated.
Findings
The study results show that the TMS has a positive effect on green innovation. Furthermore, the results indicate that at the team level, structure holes' mediation in this relationship is stronger than degree centrality; at the individual level, weak ties mediation in the relationship of specialization and green innovation is stronger than strong ties, conversely, strong ties mediation in the relationship of credibility and green innovation is stronger than weak ties.
Originality/value
This study expands previous research by highlighting the significance of multilevel social network elements in the context of the TMS and sustainable development and enriches the present research on green innovation.
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Saira Faisal, Shenela Naqvi, Muhammad Ali and Long Lin
Among various metal oxide nano particles, MgO NPs and ZnO nanoparticles (NPs) in particular are gaining increasing attention due to their multifunctional characteristics, low cost…
Abstract
Purpose
Among various metal oxide nano particles, MgO NPs and ZnO nanoparticles (NPs) in particular are gaining increasing attention due to their multifunctional characteristics, low cost and compatibility with textile materials. Each type of nanoparticle excels over others in certain properties. As such, it is often crucial to carry out comparative studies of NPs to identify the one showing higher efficiency/output for particular applications of textile products.
Design/methodology/approach
In the investigation reported in this paper, ZnO NPs and MgO NPs were synthesised via sol-gel technique and characterised. For comparative analysis, the synthesised NPs were evaluated for multiple properties using standard procedures before and after being applied on cotton fabrics by a dip-pad-dry-cure method.
Findings
XRD and FTIR analyses confirmed the successful synthesis of ZnO and MgO NPs. Homogeneous formation of desired NPs and their dense and uniform deposition on the cotton fibre surface were observed using SEM. ZnO NPs and MgO NPs coatings on cotton were observed to significantly enhance self-cleaning/stain removal properties achieving Grade 5 and Grade 4 categories, respectively. In terms of ultraviolet (UV) protection, ZnO or MgO NP coated fabrics showed UPF values of greater than 50, i.e. excellent in blocking UV rays. MgO NPs exhibited 20% cleaning efficiency in treating reactive dye wastewater against ZnO NPs which were 4% efficient in the same treatment, so MgO was more suitable for such type of treatments at low cost. Both NPs were able to impart multifunctionality to cotton fabrics as per requirement of the end products. However, ZnO NPs were better for stain removal from the fabrics while MgO NPs were appropriate for UV blocking.
Originality/value
It was therefore clear that multifunctional textile products could be developed by employing a single type of cost effective and efficient nano particles.
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Shuai Yang, Wenjie Zhao, Yongzhen Ke, Jiaying Liu and Yongjiang Xue
Due to the inability to directly apply an intra-oral image with esthetic restoration to restore tooth shape in the computer-aided design system, this paper aims to propose a…
Abstract
Purpose
Due to the inability to directly apply an intra-oral image with esthetic restoration to restore tooth shape in the computer-aided design system, this paper aims to propose a method that can use two-dimensional contours obtained from the image for the three-dimensional dental mesh model restoration.
Design/methodology/approach
First, intra-oral image and smiling image are taken from the patient, then teeth shapes of the images are designed based on esthetic restoration concepts and the pixel coordinates of the teeth’s contours are converted into the vertex coordinates in the three-dimensional space. Second, the dental mesh model is divided into three parts – active part, passive part and fixed part – based on the teeth’s contours of the mesh model. Third, the vertices from the teeth’s contours of the dental model are matched with ones from the intra-oral image and with the help of matching operation, the target coordinates of each vertex in the active part can be calculated. Finally, the Laplacian-based deformation algorithm and mesh smoothing algorithm are performed.
Findings
Benefitting from the proposed method, the dental mesh model with esthetic restoration can be quickly obtained based on the intra-oral image that is the result of doctor-patient communication. Experimental results show that the quality of restoration meets clinical needs, and the typical time cost of the method is approximately one second. So the method is both time-saving and user-friendly.
Originality/value
The method provides the possibility to design personalized dental esthetic restoration solutions rapidly.