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1 – 10 of over 1000Fei Xu, Zheng Wang, Wei Hu, Caihao Yang, Xiaolong Li, Yaning Zhang, Bingxi Li and Gongnan Xie
The purpose of this paper is to develop a coupled lattice Boltzmann model for the simulation of the freezing process in unsaturated porous media.
Abstract
Purpose
The purpose of this paper is to develop a coupled lattice Boltzmann model for the simulation of the freezing process in unsaturated porous media.
Design/methodology/approach
In the developed model, the porous structure with complexity and disorder was generated by using a stochastic growth method, and then the Shan-Chen multiphase model and enthalpy-based phase change model were coupled by introducing a freezing interface force to describe the variation of phase interface. The pore size of porous media in freezing process was considered as an influential factor to phase transition temperature, and the variation of the interfacial force formed with phase change on the interface was described.
Findings
The larger porosity (0.2 and 0.8) will enlarge the unfrozen area from 42 mm to 70 mm, and the rest space of porous medium was occupied by the solid particles. The larger specific surface area (0.168 and 0.315) has a more fluctuated volume fraction distribution.
Originality/value
The concept of interfacial force was first introduced in the solid–liquid phase transition to describe the freezing process of frozen soil, enabling the formulation of a distribution equation based on enthalpy to depict the changes in the water film. The increased interfacial force serves to diminish ice formation and effectively absorb air during the freezing process. A greater surface area enhances the ability to counteract liquid migration.
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Chang Liu, Shiwu Yang, Yixuan Yang, Hefei Cao and Shanghe Liu
In the continuous development of high-speed railways, ensuring the safety of the operation control system is crucial. Electromagnetic interference (EMI) faults in signaling…
Abstract
Purpose
In the continuous development of high-speed railways, ensuring the safety of the operation control system is crucial. Electromagnetic interference (EMI) faults in signaling equipment may cause transportation interruptions, delays and even threaten the safety of train operations. Exploring the impact of disturbances on signaling equipment and establishing evaluation methods for the correlation between EMI and safety is urgently needed.
Design/methodology/approach
This paper elaborates on the necessity and significance of studying the impact of EMI as an unavoidable and widespread risk factor in the external environment of high-speed railway operations and continuous development. The current status of research methods and achievements from the perspectives of standard systems, reliability analysis and safety assessment are examined layer by layer. Additionally, it provides prospects for innovative ideas for exploring the quantitative correlation between EMI and signaling safety.
Findings
Despite certain innovative achievements in both domestic and international standard systems and related research for ensuring and evaluating railway signaling safety, there’s a lack of quantitative and strategic research on the degradation of safety performance in signaling equipment due to EMI. A quantitative correlation between EMI and safety has yet to be established. On this basis, this paper proposes considerations for research methods pertaining to the correlation between EMI and safety.
Originality/value
This paper overviews a series of methods and outcomes derived from domestic and international studies regarding railway signaling safety, encompassing standard systems, reliability analysis and safety assessment. Recognizing the necessity for quantitatively describing and predicting the impact of EMI on high-speed railway signaling safety, an innovative approach using risk assessment techniques as a bridge to establish the correlation between EMI and signaling safety is proposed.
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Yuanwen Han, Jiang Shen, Xuwei Zhu, Bang An and Xueying Bao
This study aims to develop an interface management risk interaction modeling and analysis methodology applicable to complex systems in high-speed rail construction projects…
Abstract
Purpose
This study aims to develop an interface management risk interaction modeling and analysis methodology applicable to complex systems in high-speed rail construction projects, reveal the interaction mechanism of interface management risk and provide theoretical support for project managers to develop appropriate interface management risk response strategies.
Design/methodology/approach
This paper introduces the association rule mining technique to improve the complex network modeling method. Taking China as an example, based on the stakeholder perspective, the risk factors and significant accident types of interface management of high-speed rail construction projects are systematically identified, and a database is established. Then, the Apriori algorithm is used to mine and analyze the strong association rules among the factors in the database, construct the complex network, and analyze its topological characteristics to reveal the interaction mechanism of the interface management risk of high-speed rail construction projects.
Findings
The results show that the network is both scale-free and small-world, implying that construction accidents are not random events but rather the result of strong interactions between numerous interface management risks. Contractors, technical interfaces, mechanical equipment, and environmental factors are the primary direct causal factors of accidents, while owners and designers are essential indirect causal factors. The global importance of stakeholders such as owners, designers, and supervisors rises significantly after considering the indirect correlations between factors. This theoretically explains the need to consider the interactions between interface management risks.
Originality/value
The interaction mechanism between interface management risks is unclear, which is an essential factor influencing the decision of risk response measures. This study proposes a new methodology for analyzing interface management risk response strategies that incorporate quantitative analysis methods and considers the interaction of interface management risks.
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Dat Van Truong, Song Thanh Quynh Le and Huong Mai Bui
Kapok was well-known for its oleophilic properties, but its mechanical properties and morphology impeded it from forming suitable absorbent materials. This study aims to…
Abstract
Purpose
Kapok was well-known for its oleophilic properties, but its mechanical properties and morphology impeded it from forming suitable absorbent materials. This study aims to demonstrate the process of creating an oil-absorbent web from a blend of treated kapok and polypropylene fibers.
Design/methodology/approach
Kapok fibers were separated from dried fruits, then the wax was removed with an HCl solution at different concentrations. The morphological and structural changes of these fibers were investigated using scanning electron microscopy images. The blending ratios of kapok and polypropylene fibers were 60/40, 70/30 and 80/20, respectively. The fiber blends were fed to a laboratory carding machine to form a web and then consolidated using the heat press technique. The absorption behavior of the formed web was evaluated regarding oil absorption capacity and oil retention capacity according to ASTM 726.
Findings
The results showed that the HCl concentration of 1.0% (wt%) gave the highest wax removal efficiency without damaging the kapok fibers. This study found that oil absorbency is influenced by the fiber blending ratio, web tensile strength and elongation, porosity, oil type and environmental conditions. The oil-absorbency of the web can be re-used for at least 20 cycles.
Research limitations/implications
This study only looked at three types of oils: diesel, kerosene and vegetable oils.
Practical implications
When the problem of oil spills in rivers and seas is growing and causing serious environmental and economic consequences, using physical methods to recover oil spills is the most effective solution.
Originality/value
This research adds to the possibility of using kapok fiber in the form of a web of non-woven fabric for practical purposes.
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Yuting Lu, Wanwan Fu, hao Ren, Shifang Wu, Jiesheng Liu and Hao Peng
The purpose of this paper is to develop a high-performance composite emulsion cement waterproof coating. The coating has excellent durability and is effective in protecting cement…
Abstract
Purpose
The purpose of this paper is to develop a high-performance composite emulsion cement waterproof coating. The coating has excellent durability and is effective in protecting cement mortar substrates from harmful ions.
Design/methodology/approach
The polymer cement waterproof coatings with different emulsion compounding ratios were tested for mechanical properties and water resistance after alkali immersion, water immersion, thermal aging and UV aging, and the coatings were analyzed by infrared spectroscopy after aging to evaluate its durability. Meanwhile, the coating that presents favorable durability was applied to cement mortar test blocks. The protective effect of the coating on the test blocks was tested by immersion method, and X-ray diffraction analysis was performed on the eroded test blocks.
Findings
The coating with neoprene latex/acrylate latex weight ratio of 90/10 presents favorable durability and has superior overall performance. Besides, when it is applied to cement mortar blocks, the coatings effectively reduced the erosive effect of harmful ions on cement mortar blocks, resulting in much lower mass change ratios and less internal structural damage of the blocks significantly.
Originality/value
The obtained coating will be of great application potential for use in building waterproofing construction. Moreover, the coating can practically prevent chloride ions and sulfate ions from penetrating cement-based materials.
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Whilst professional learning communities (PLCs) have been widely explored at the school level, they have received less attention at the departmental level. The study takes the…
Abstract
Purpose
Whilst professional learning communities (PLCs) have been widely explored at the school level, they have received less attention at the departmental level. The study takes the variance between departments and the role of departmental teacher leaders into consideration, and the relationships amongst departmental-level PLC dimensions, two types of teacher leadership (TL) and individual teacher self-efficacy are investigated.
Design/methodology/approach
The sample consisted of 907 teachers from 81 departments in Chinese schools. The associations between the studied variables were explored through a multi-level analysis approach.
Findings
The results show that two specific characteristics of departmental PLCs, namely reflective dialogue (RD) and collective responsibility (CR), exhibit a positive correlation with individual teacher self-efficacy. Additionally, the findings indicate that teacher transformational leadership significantly predicts teacher self-efficacy, whereas teacher instructional leadership (IL) does not emerge as a significant predictor. These findings may be attributed to the contextual factors of Chinese teachers' collective work and the practice of teacher leaders.
Originality/value
This research contributes to the existing literature by addressing the variance between departments and uncovering the impacts of departmental PLC dimensions on individual teachers. Furthermore, two TL styles at the departmental level are differentiated, and their distinct influences on teacher self-efficacy are further analysed.
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Yu Wang, Daqing Zheng and Yulin Fang
The advancement of enterprise social networks (ESNs) facilitates information sharing but also presents the challenge of managing information boundaries. This study aims to explore…
Abstract
Purpose
The advancement of enterprise social networks (ESNs) facilitates information sharing but also presents the challenge of managing information boundaries. This study aims to explore the factors that influence the information-control behavior of ESN users when continuously sharing information.
Design/methodology/approach
This study specifies the information-control behaviors in the “wall posts” channel and applies communication privacy management (CPM) theory to analyze the effects of the individual-specific factor (disposition to value information), context-specific factors (work-relatedness and information richness) and risk-benefit ratio (public benefit and public risk). Data on actual information-control behaviors extracted from ESN logs are examined using multilevel mixed-effects logistic regression analysis.
Findings
The study's findings show the direct effects of the individual-specific factor, context-specific factors and risk-benefit ratio, highlighting interactions between the individual motivation factor and ESN context factors.
Originality/value
This study reshapes the relationship of CPM theory boundary rules in the ESN context, extending information-control research and providing insights into ESNs' information-control practices.
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Wang Zengqing, Zheng Yu Xie and Jiang Yiling
With the rapid development of railway-intelligent video technology, scene understanding is becoming more and more important. Semantic segmentation is a major part of scene…
Abstract
Purpose
With the rapid development of railway-intelligent video technology, scene understanding is becoming more and more important. Semantic segmentation is a major part of scene understanding. There is an urgent need for an algorithm with high accuracy and real-time to meet the current railway requirements for railway identification. In response to this demand, this paper aims to explore a variety of models, accurately locate and segment important railway signs based on the improved SegNeXt algorithm, supplement the railway safety protection system and improve the intelligent level of railway safety protection.
Design/methodology/approach
This paper studies the performance of existing models on RailSem19 and explores the defects of each model through performance so as to further explore an algorithm model dedicated to railway semantic segmentation. In this paper, the authors explore the optimal solution of SegNeXt model for railway scenes and achieve the purpose of this paper by improving the encoder and decoder structure.
Findings
This paper proposes an improved SegNeXt algorithm: first, it explores the performance of various models on railways, studies the problems of semantic segmentation on railways and then analyzes the specific problems. On the basis of retaining the original excellent MSCAN encoder of SegNeXt, multiscale information fusion is used to further extract detailed features such as multihead attention and mask, solving the problem of inaccurate segmentation of current objects by the original SegNeXt algorithm. The improved algorithm is of great significance for the segmentation and recognition of railway signs.
Research limitations/implications
The model constructed in this paper has advantages in the feature segmentation of distant small objects, but it still has the problem of segmentation fracture for the railway, which is not completely segmented. In addition, in the throat area, due to the complexity of the railway, the segmentation results are not accurate.
Social implications
The identification and segmentation of railway signs based on the improved SegNeXt algorithm in this paper is of great significance for the understanding of existing railway scenes, which can greatly improve the classification and recognition ability of railway small object features and can greatly improve the degree of railway security.
Originality/value
This article introduces an enhanced version of the SegNeXt algorithm, which aims to improve the accuracy of semantic segmentation on railways. The study begins by investigating the performance of different models in railway scenarios and identifying the challenges associated with semantic segmentation on this particular domain. To address these challenges, the proposed approach builds upon the strong foundation of the original SegNeXt algorithm, leveraging techniques such as multi-scale information fusion, multi-head attention, and masking to extract finer details and enhance feature representation. By doing so, the improved algorithm effectively resolves the issue of inaccurate object segmentation encountered in the original SegNeXt algorithm. This advancement holds significant importance for the accurate recognition and segmentation of railway signage.
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Abstract
Purpose
Social media's role in engaging participants in sports events, particularly during the pandemic, is acknowledged. However, previous studies often utilized sports events for diverse objectives but overlooked brand equity's influence on sports event development. And very limited research explores social media's impact on brand equity in esports events, despite its significance. Therefore, this study aims to explore how social media affects esports event brand equity and participants' satisfaction and engagement with social media through brand equity's influence.
Design/methodology/approach
The study focused on League of Legends World Championships (LOLWC) participants, who completed a self-judged questionnaire online. The questionnaire included demographic details and latent constructs. Data analysis involved two steps: exploratory factor analysis (EFA) to assess measurement scale validity and structural equation modeling (SEM) to study relationships between traits.
Findings
The results reveal that, within the esports event context, controlled communication exerts a meaningful and dual impact – both directly and indirectly – on the fundamental components of brand equity. This, in turn, serves as a catalyst for increasing participant contentment and their posting intention.
Originality/value
This study applies brand equity theories to the esports domain, exploring participant-based brand equity concepts, user behavior and the influence of social media communication on event branding and engagement. It also recommends strategies for event improvement, emphasizes controlled communication for brand equity and highlights marketing's role in brand awareness, association and participant satisfaction. Additionally, it suggests government regulation to address cyber violence during esports events.
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Jian Zheng, Renjing Liu, Ru Zhang and Hao Xu
In the context of virtual brand communities (VBCs), based on self-determination theory and organizational binary learning (OBL) theory, this study investigates the direct and…
Abstract
Purpose
In the context of virtual brand communities (VBCs), based on self-determination theory and organizational binary learning (OBL) theory, this study investigates the direct and indirect effects of various dimensions of consumer participation (CP) on firm innovation performance (FIP) and the mediating role of OBL. By introducing the perspective of knowledge absorptive capacity (KAC), this study examines the moderating effect of KAC on the relationship between OBL and TIP.
Design/methodology/approach
In this study, 751 samples are collected from Chinese firms, and stratified adjusted regression analysis is used to conduct empirical tests.
Findings
Information provision or co-creation directly affects FIP; the latter is more significant than the former, while social interaction does not directly affect FIP. Exploitative or exploratory learning plays a mediating role in the relationship between information provision or co-creation and FIP. In contrast, exploratory learning plays a mediating role in the relationship between social interaction and FIP. KAC has a positive moderating effect on the relationship between exploitative learning or exploratory learning and FIP. When the firm has a low KAC, the improvement of FIP through exploratory learning is slight.
Originality/value
In VBCs, this study tries to divide the dimensions of CP. It also clarifies the mediating effect of OBL on CP and FIP. In addition, it explores the moderating effect of KAC on OBL and FIP. The conclusions of this study provide theoretical support and practical inspiration for firms to use VBCs to improve FIP.
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