Linjie Su, Bohong Li, Dongyu Zhao, Chuanli Qin and Zheng Jin
The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor.
Abstract
Purpose
The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor.
Design/methodology/approach
In this study, the specific capacitance of ACF was significantly increased by using the phenolic resin microspheres and melamine as modifiers to prepare modified PAN-based activated carbon fibers (MACFs) via electrospinning, pre-oxidation and carbonization. The symmetrical supercapacitor (using MACF as electrode) and hybrid supercapacitor (using MACF and activated carbon as electrodes) were tested in term of electrochemical properties by cyclic voltammetry, AC impedance and cycle stability test.
Findings
It was found that the specific capacitance value of the modified fibers were increased to 167 Fg-1 by adding modifiers (i.e. 20 wt.% microspheres and 15 wt.% melamine) compared to that of unmodified fibers (86.17 Fg-1). Specific capacitance of modified electrode material had little degradation over 10,000 cycles. This result can be attributed to that the modifiers embedded into the fibers changed the original morphology and enhanced the specific surface area of the fibers.
Originality/value
The modified ACFs in our study had high specific surface area and significantly high specific capacitance, which can be applied as efficient and environmental absorbent, and advanced electrode material of supercapacitor.
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Keywords
Dongyu Zhao, Shuhong Wang, Jie Wu, Xuduo Bai and Qingquan Lei
The purpose of this paper is to study a new method with which multi‐walled carbon nanotubes (MWNTs) can be dispersed and aligned in low density polyethylene (LDPE) for improving…
Abstract
Purpose
The purpose of this paper is to study a new method with which multi‐walled carbon nanotubes (MWNTs) can be dispersed and aligned in low density polyethylene (LDPE) for improving its mechanical properties.
Design/methodology/approach
Dispersion and alignment of MWNTs in LDPE matrix are enhanced by ultrasonic vibration, solution casting and melt mixing and flow moulding method. The properties of the composite are characterised using scanning electron microscopy, tensile testing machine and the Izod impact testing machine.
Findings
It is found that MWNTs in LDPE achieve some dispersion and alignment resulting in improvement in LDPE's strength and toughness.
Practical implications
Polymer/CNTs nanocomposites are expected to have good process ability of the polymers and high mechanical and functional properties of the CNTs. Enhancing dispersion and alignment of MWNTs in the polymer matrix will promote and expand the applications and development of polymer/MWNTs nanocomposites.
Originality/value
The method that enhances MWNTs dispersion and alignment in LDPE matrix provides a new way for alignment of other CNTs in polymer matrix.
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Keywords
Xiaoming Zhang, Huilin Chen, Yanqin Ruan, Dongyu Pan and Chongchong Zhao
With the rapid development of materials informatics and the Semantic Web, the semantic-driven solution has emerged to improve traditional query technology, which is hard to…
Abstract
Purpose
With the rapid development of materials informatics and the Semantic Web, the semantic-driven solution has emerged to improve traditional query technology, which is hard to discover implicit knowledge from materials data. However, it is a nontrivial thing for materials scientists to construct a semantic query, and the query results are usually presented in RDF/XML format which is not convenient for users to understand. This paper aims to propose an approach to construct semantic query and visualize the query results for metallic materials domain.
Design/methodology/approach
The authors design a query builder to generate SPARQL query statements automatically based on domain ontology and query conditions inputted by users. Moreover, a semantic visualization model is defined based on the materials science tetrahedron to support the visualization of query results in an intuitive, dynamic and interactive way.
Findings
Based on the Semantic Web technology, the authors design an automatic semantic query builder to help domain experts write the normative semantic query statements quickly and simply, as well as a prototype (named MatViz) is developed to visually show query results, which could help experts discover implicit knowledge from materials data. Moreover, the experiments demonstrate that the proposed system in this paper can rapidly and effectively return visualized query results over the metallic materials data set.
Originality/value
This paper mainly discusses an approach to support semantic query and visualization of metallic materials data. The implementation of MatViz will be a meaningful work for the research of metal materials data integration.
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Keywords
Xiaoming Zhang, Kai Li, Chongchong Zhao and Dongyu Pan
With the increasing spread of ontologies in various domains, units have gradually become an essential part of ontologies and units ontologies have been developed to offer a better…
Abstract
Purpose
With the increasing spread of ontologies in various domains, units have gradually become an essential part of ontologies and units ontologies have been developed to offer a better expression ability for the practical usage. From the perspectives of architecture, comparison and reuse, the purpose of this paper is to provide a comprehensive survey on four mainstream units ontologies: quantity-unit-dimension-type, quantities, units, dimensions and values, ontology of units of measure and units ontology (UO) of the open biomedical ontologies, in order to address well the state of the art and the reuse strategies of the UO.
Design/methodology/approach
An architecture of units ontologies is presented, in which the relations between key factors (i.e. units of measure, quantity and dimension) are discussed. The criteria for comparing units ontologies are developed from the perspectives of organizational structure, pattern design and application scenario. Then, the authors compare four typical units ontologies based on the proposed comparison criteria. Furthermore, how to reuse these units ontologies is discussed in materials science domain by utilizing two reuse strategies of partial reference and complete reference.
Findings
Units ontologies have attracted high attention in the scientific domain. Based on the comparison of four popular units ontologies, this paper finds that different units ontologies have different design features from the perspectives of basis structure, units conversion and axioms design; a UO is better to be applied to the application areas that satisfy its design features; and many challenges remain to be done in the future research of the UO.
Originality/value
This paper makes an extensive review on units ontologies, by defining the comparison criteria and discussing the reuse strategies in the materials domain. Based on this investigation, guidelines are summarized for the selection and reuse of units ontologies.
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Zhou Su, Xiangwang Kong, Tao He, Dongyu Wu, Jingjing Wu and Shaohe Zhang
Material extrusion technology is considered to be an effective way to realize the accurate and integrated manufacturing of high-performance metal diamond tools with complex…
Abstract
Purpose
Material extrusion technology is considered to be an effective way to realize the accurate and integrated manufacturing of high-performance metal diamond tools with complex structures. The present work aims to report the G4 binder that can be used to create metal composite filament loading high concentrations of large diamond particles through comparative experiments.
Design/methodology/approach
The quality of filaments was evaluated by surface topography observation and porosity measurement. And the printability of filaments was further studied by the tensile test, rheological test, shear analysis and printing test.
Findings
The results show that the G4 binder exhibits the best capacity for loading diamonds among G1–G4. The L4 filament created with G4 has no defects such as pores, cracks and patterns on the surface and section, and has the lowest porosity, which is about 1/3 of the L1. Therefore, the diamond-containing composite filament based on G4 binder exhibits the best quality. On the other hand, the results of the tensile test of L5–L8 filaments reveal that as the diamond content increases from 10% to 30%, the tensile strength of the filament decreases by 29.52%, and the retention force coefficient decreases by 15.74%. This can be attributed to the formation of inefficient bonding areas of the clustered diamond particles inside the composite filament, which also leads to a weakening of the shear strength. Despite this, the results of the printing test show that the diamond-containing composite filament based on the G4 binder has reliable printability.
Originality/value
Therefore, the G4 binder is considered to solve the most critical first challenge in the development of diamond-containing filament.
Details
Keywords
Gangling Hou, Yu Liu, Meng Li, Menghan Sun, Feng Sun, Xiuyun Zhu, Rong Pan and Dongyu Zhang
In recent years, a new type of double-layered containment structure of nuclear power plant has been built in China, named ACP1000 NNP. This paper aims to propose a new method to…
Abstract
Purpose
In recent years, a new type of double-layered containment structure of nuclear power plant has been built in China, named ACP1000 NNP. This paper aims to propose a new method to mitigate the seismic responses of this type of the structure.
Design/methodology/approach
The new base isolation structure (BIS)- tuned mass damper (TMD) structure was proposed and implemented only by modifying the connection between various components of NPPs, and the application of this concept design in ACP1000 was skillfully realized.
Findings
The new structure adopts the combination of structural form and function, adopts appropriate amplification of the seismic response of the secondary component, possesses advantages in explicit damping mechanism, good damping effect, robustness of seismic structures, simple implementation process, etc., and meets the special seismic safety requirements of the NPPs.
Originality/value
This seismic and hazard mitigation and BIS-TMD structure can avoid the risk of ACP1000 accidents caused by horizontal earthquakes.
Details
Keywords
Yi liu, Ping Li, Boqing Feng, Peifen Pan, Xueying Wang and Qiliang Zhao
This paper analyzes the application of digital twin technology in the field of intelligent operation and maintenance of high-speed railway infrastructure from the perspective of…
Abstract
Purpose
This paper analyzes the application of digital twin technology in the field of intelligent operation and maintenance of high-speed railway infrastructure from the perspective of top-level design.
Design/methodology/approach
This paper provides a comprehensive overview of the definition, connotations, characteristics and key technologies of digital twin technology. It also conducts a thorough analysis of the current state of digital twin applications, with a particular focus on the overall requirements for intelligent operation and maintenance of high-speed railway infrastructure. Using the Jinan Yellow River Bridge on the Beijing–Shanghai high-speed railway as a case study, the paper details the construction process of the twin system from the perspectives of system architecture, theoretical definition, model construction and platform design.
Findings
Digital twin technology can play an important role in the whole life cycle management, fault prediction and condition monitoring in the field of high-speed rail operation and maintenance. Digital twin technology is of great significance to improve the intelligent level of high-speed railway operation and management.
Originality/value
This paper systematically summarizes the main components of digital twin railway. The general framework of the digital twin bridge is given, and its application in the field of intelligent operation and maintenance is prospected.
Details
Keywords
Xia Wang, Hong Ren, Weiguang Cai, Yan Liu and Lizi Luo
Green building (GB) has been actively promoted in many countries, but it has not become the mainstream in Chinese construction industry due to various reasons. This paper aims to…
Abstract
Green building (GB) has been actively promoted in many countries, but it has not become the mainstream in Chinese construction industry due to various reasons. This paper aims to investigate the major driving factors for the development of GB with reference of the Chinese construction market. Twenty-one factors influencing the development of GB were identified through a literature review, questionnaire survey, and face-to-face interview with professionals in the construction industry. Structural equation model was established to identify the critical driving path and three critical factors hierarchies. The result of model analysis also verifies the theoretical hypotheses that government body is the biggest motivation for the development of GB, and the path coefficient is high. The results demonstrate the necessity for the formulation of incentive policies and power of GB propaganda. We identify distinct government and market effects and then induce a government-led GB development path. These findings provide a valuable reference for government body aiming at promoting GB in the construction industry to put forward relevant policies and incentives and for the market body to understand the major driving factors and path when making decisions.
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Keywords
Ting Li, Jinsheng Zhang, Shicheng Wang, Dongyu Li, Zhifeng Lv and Jiangjun Jiang
This study aims to find a novel solution to the calibration of three-axis magnetometers to suppress errors of sensors. The nature of the calibration process is parameter…
Abstract
Purpose
This study aims to find a novel solution to the calibration of three-axis magnetometers to suppress errors of sensors. The nature of the calibration process is parameter estimation and hence the purpose of the paper is to calculate the error parameters and eliminate sensor errors and obtain the true value of the pure magnetic field.
Design/methodology/approach
The paper puts forward a calibration method using an alternative iteration looping optimization (AILO) to estimate the parameters. The proposed method divided the parameters to be estimated into two parts: a portion less than one and the other greater than one. Parameters with different orders of magnitude are calculated respectively, which let one part to be a known quantity and the other part is derived by the known quantity; the derived quantity is used to calculate the known quantity again, and looping iteration multiple times until the iteration termination condition is satisfied.
Findings
The simulation and experimental results indicate that the calibration accuracy is improved at least by two orders by the proposed method compared to the two-step method and the linear decreasing weight particle swarm optimization (LDW-PSO) algorithm which proves the validity of the proposed method.
Practical implications
The proposed method can improve the calibration accuracy of total magnetic field, which provides a reference to the calibration of three-axis magnetometers.
Originality/value
A calibration method based on the AILO is proposed in this paper, which is used to improve the calibration accuracy of the three-axis magnetometer.
Details
Keywords
Yongqiang Lu and Li Ma
Construction project team members’ job burnout damages the physical health of members and also have a negative effect on project performance. This study primarily aims to…
Abstract
Purpose
Construction project team members’ job burnout damages the physical health of members and also have a negative effect on project performance. This study primarily aims to empirically examine the relationship between coaching project managers (CPMs) and team members’ job burnout. Moreover, this research examines the cross-level mediating effect of team caring ethical climate and team members’ team-based self-esteem (TBSE) on the relationship between the two aspects.
Design/methodology/approach
This study uses conservation of resources theory as basis to construct a cross-level research model of the effect of CPMs on team members’ job burnout. Thereafter, regression analysis was performed on a sample of 431 team members from 83 teams.
Findings
According to the empirical results, the authors found that, in construction project teams, first, CPMs were negatively correlated with team members’ job burnout and positively correlated with caring ethical climate and team members’ TBSE. Second, caring ethical climate and team members’ TBSE played a cross-level mediating role between CPMs and team members’ job burnout. In addition, caring ethical climate played a cross-level moderating role in the negative relationship between team members’ TBSE and job burnout.
Originality/value
This study introduces coaching leadership, an important leadership type, into the research background of construction project teams, thereby theoretically enriching the research on construction project team leadership. Moreover, by further expanding the research on the consequences of coaching leadership to the field of job burnout, this study also enriches the theoretical results of the research on the consequences of coaching leadership.