Search results
1 – 10 of 219Yong Li, Yingchun Zhang, Gongnan Xie and Bengt Ake Sunden
This paper aims to comprehensively clarify the research status of thermal transport of supercritical aviation kerosene, with particular interests in the effect of cracking on heat…
Abstract
Purpose
This paper aims to comprehensively clarify the research status of thermal transport of supercritical aviation kerosene, with particular interests in the effect of cracking on heat transfer.
Design/methodology/approach
A brief review of current research on supercritical aviation kerosene is presented in views of the surrogate model of hydrocarbon fuels, chemical cracking mechanism of hydrocarbon fuels, thermo-physical properties of hydrocarbon fuels, turbulence models, flow characteristics and thermal performances, which indicates that more efforts need to be directed into these topics. Therefore, supercritical thermal transport of n-decane is then computationally investigated in the condition of thermal pyrolysis, while the ASPEN HYSYS gives the properties of n-decane and pyrolysis products. In addition, the one-step chemical cracking mechanism and SST k-ω turbulence model are applied with relatively high precision.
Findings
The existing surrogate models of aviation kerosene are limited to a specific scope of application and their thermo-physical properties deviate from the experimental data. The turbulence models used to implement numerical simulation should be studied to further improve the prediction accuracy. The thermal-induced acceleration is driven by the drastic density change, which is caused by the production of small molecules. The wall temperature of the combustion chamber can be effectively reduced by this behavior, i.e. the phenomenon of heat transfer deterioration can be attenuated or suppressed by thermal pyrolysis.
Originality/value
The issues in numerical studies of supercritical aviation kerosene are clearly revealed, and the conjugation mechanism between thermal pyrolysis and convective heat transfer is initially presented.
Details
Keywords
Shruti Garg, Rahul Kumar Patro, Soumyajit Behera, Neha Prerna Tigga and Ranjita Pandey
The purpose of this study is to propose an alternative efficient 3D emotion recognition model for variable-length electroencephalogram (EEG) data.
Abstract
Purpose
The purpose of this study is to propose an alternative efficient 3D emotion recognition model for variable-length electroencephalogram (EEG) data.
Design/methodology/approach
Classical AMIGOS data set which comprises of multimodal records of varying lengths on mood, personality and other physiological aspects on emotional response is used for empirical assessment of the proposed overlapping sliding window (OSW) modelling framework. Two features are extracted using Fourier and Wavelet transforms: normalised band power (NBP) and normalised wavelet energy (NWE), respectively. The arousal, valence and dominance (AVD) emotions are predicted using one-dimension (1D) and two-dimensional (2D) convolution neural network (CNN) for both single and combined features.
Findings
The two-dimensional convolution neural network (2D CNN) outcomes on EEG signals of AMIGOS data set are observed to yield the highest accuracy, that is 96.63%, 95.87% and 96.30% for AVD, respectively, which is evidenced to be at least 6% higher as compared to the other available competitive approaches.
Originality/value
The present work is focussed on the less explored, complex AMIGOS (2018) data set which is imbalanced and of variable length. EEG emotion recognition-based work is widely available on simpler data sets. The following are the challenges of the AMIGOS data set addressed in the present work: handling of tensor form data; proposing an efficient method for generating sufficient equal-length samples corresponding to imbalanced and variable-length data.; selecting a suitable machine learning/deep learning model; improving the accuracy of the applied model.
Details
Keywords
Yong Chen, Zhixian Zhan and Wei Zhang
As the strategy of 5G new infrastructure is deployed and advanced, 5G-R becomes the primary technical system for future mobile communication of China’s railway. V2V communication…
Abstract
Purpose
As the strategy of 5G new infrastructure is deployed and advanced, 5G-R becomes the primary technical system for future mobile communication of China’s railway. V2V communication is also an important application scenario of 5G communication systems on high-speed railways, so time synchronization between vehicles is critical for train control systems to be real-time and safe. How to improve the time synchronization performance in V2V communication is crucial to ensure the operational safety and efficiency of high-speed railways.
Design/methodology/approach
This paper proposed a time synchronization method based on model predictive control (MPC) for V2V communication. Firstly, a synchronous clock for V2V communication was modeled based on the fifth generation mobile communication-railway (5G-R) system. Secondly, an observation equation was introduced according to the phase and frequency offsets between synchronous clocks of two adjacent vehicles to construct an MPC-based space model of clock states of the adjacent vehicles. Finally, the optimal clock offset was solved through multistep prediction, rolling optimization and other control methods, and time synchronization in different V2V communication scenarios based on the 5G-R system was realized through negative feedback correction.
Findings
The results of simulation tests conducted with and without a repeater, respectively, show that the proposed method can realize time synchronization of V2V communication in both scenarios. Compared with other methods, the proposed method has faster convergence speed and higher synchronization precision regardless of whether there is a repeater or not.
Originality/value
This paper proposed an MPC-based time synchronization method for V2V communication under 5G-R. Through the construction of MPC controllers for clocks of adjacent vehicles, time synchronization was realized for V2V communication under 5G-R by using control means such as multistep prediction, rolling optimization, and feedback correction. In view of the problems of low synchronization precision and slow convergence speed caused by packet loss with existing synchronization methods, the observer equation was introduced to estimate the clock state of the adjacent vehicles in case of packet loss, which reduces the impact of clock error caused by packet loss in the synchronization process and improves the synchronization precision of V2V communication. The research results provide some theoretical references for V2V synchronous wireless communication under 5G-R technology.
Details
Keywords
Zhou Shi, Jiachang Gu, Yongcong Zhou and Ying Zhang
This study aims to research the development trend, research status, research results and existing problems of the steel–concrete composite joint of railway long-span hybrid girder…
Abstract
Purpose
This study aims to research the development trend, research status, research results and existing problems of the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge.
Design/methodology/approach
Based on the investigation and analysis of the development history, structure form, structural parameters, stress characteristics, shear connector stress state, force transmission mechanism, and fatigue performance, aiming at the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge, the development trend, research status, research results and existing problems are expounded.
Findings
The shear-compression composite joint has become the main form in practice, featuring shortened length and simplified structure. The length of composite joints between 1.5 and 3.0 m has no significant effect on the stress and force transmission laws of the main girder. The reasonable thickness of the bearing plate is 40–70 mm. The calculation theory and simplified calculation formula of the overall bearing capacity, the nonuniformity and distribution laws of the shear connector, the force transferring ratio of steel and concrete components, the fatigue failure mechanism and structural parameters effects are the focus of the research study.
Originality/value
This study puts forward some suggestions and prospects for the structural design and theoretical research of the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge.
Details
Keywords
The study aims to provide a basis for the effective use of safety-related information data and a quantitative assessment way for the occurrence probability of the safety risk such…
Abstract
Purpose
The study aims to provide a basis for the effective use of safety-related information data and a quantitative assessment way for the occurrence probability of the safety risk such as the fatigue fracture of the key components.
Design/methodology/approach
The fatigue crack growth rate is of dispersion, which is often used to accurately describe with probability density. In view of the external dispersion caused by the load, a simple and applicable probability expression of fatigue crack growth rate is adopted based on the fatigue growth theory. Considering the isolation among the pairs of crack length a and crack formation time t (a∼t data) obtained from same kind of structural parts, a statistical analysis approach of t distribution is proposed, which divides the crack length in several segments. Furthermore, according to the compatibility criterion of crack growth, that is, there is statistical development correspondence among a∼t data, the probability model of crack growth rate is established.
Findings
The results show that the crack growth rate in the stable growth stage can be approximately expressed by the crack growth control curve da/dt = Q•a, and the probability density of the crack growth parameter Q represents the external dispersion; t follows two-parameter Weibull distribution in certain a values.
Originality/value
The probability density f(Q) can be estimated by using the probability model of crack growth rate, and a calculation example shows that the estimation method is effective and practical.
Details
Keywords
Md. Rabiul Awal, Md. Shakhawat Hossain, Tahmina Akter Arzin, Md. Imran Sheikh and Md. Enamul Haque
Online shopping around the world is growing exponentially, especially during the COVID-19 pandemic. This study aims to examine how an online customer's purchasing experience…
Abstract
Purpose
Online shopping around the world is growing exponentially, especially during the COVID-19 pandemic. This study aims to examine how an online customer's purchasing experience influences his/her buying intention and willingness to believe in fraud news, as well as the ripple impact of satisfaction and trust, with gender as a moderator in an emerging economy during COVID-19.
Design/methodology/approach
Based on the underpinning of the stimulus-organism-behavior-consequence (SOBC) theory, the research model was developed, and collected data from 259 respondents using convenience samples technique. Next, the data were analyzed using partial least squares-based structural equation modeling (PLS-SEM), SPSS (Statistical Package for the Social Sciences) and Hayes Process Macro.
Findings
The study results confirmed that the online shopping experience (OSE) has positive impact on customers' satisfaction (CS), purchase intention (PI) and customer trust (CT); CS has positive effects on trust toward online shopping and their future product PI; future product PI significantly affects customers' propensity to believe and act on fraud news (PBAFN). The finding also states that gender moderates the relationships of CS to PI, OSE to PI and PI to PBAFN, but doesn't moderate the CT to PI relationship.
Originality/value
The study findings will assist policymakers and online vendors to win customers' hearts and minds' through confirming satisfaction, trust and a negative attitude toward fake news, which will lead to customer loyalty and the sustainable development of the industry. Finally, the limitations and future research directions are discussed.
Details
Keywords
Talat Islam, Saleha Sharif, Hafiz Fawad Ali and Saqib Jamil
Nurses' turnover intention has become a major issue in developing countries with high power distance cultures. Therefore, the authors attempt to investigate how turnover intention…
Abstract
Purpose
Nurses' turnover intention has become a major issue in developing countries with high power distance cultures. Therefore, the authors attempt to investigate how turnover intention among nurses' can be reduced through paternalistic leadership (PL). The authors further investigate the mediating role of job satisfaction between the associations of benevolent, moral and authoritarian dimensions of PL with turnover intention. Finally, the authors examined perceived organizational support (POS) as a conditional variable between job satisfaction and turnover intention.
Design/methodology/approach
The authors collected data from 374 nurses working in public and private hospitals of high power distance culture using a questionnaire-based survey on convenience basis.
Findings
Structural equation modeling confirms that benevolent and moral dimensions of PL positively affect nurses' job satisfaction which helps them reduce their turnover intention. While the authoritarian dimension of PL negatively affects job satisfaction to further enhance their turnover intention. In addition, the authors noted POS as a conditional variable to trigger the negative effect of job satisfaction on turnover intention.
Research limitations/implications
The authors used a cross-sectional design to collect responses and ensured the absence of common method variance through Harman's Single factor test.
Originality/value
This study identified the mechanism (job satisfaction and POS) through which benevolent, moral and authoritative dimensions of PL predict turnover intention among nurses working in high power distance culture.
研究目的
護士有離職意向,在擁有高權力距離文化的發展中國家,已成為一個重大的問題。因此,我們擬探討如何可以透過採用家長式領導、把護士離職的意欲減低,繼而研究工作滿足感,在離職意向與家長式領導中仁慈、道德和獨裁這三個層面的關係中所起的中介作用。最後,我們就組織支持感,作為是工作滿足感與離職意向之間的一個條件變數,進行了研究。
研究設計/方法/理念
本研究透過採用在便利的基礎上進行的問卷調查,從374名在高權力距離文化的公營和私營醫院內工作的護士取得數據,進行分析。
研究結果
結構方程模型證實了家長式領導中的仁慈和道德這兩個層面,會對可減低護士離職意欲的工作滿足感,產生積極的影響。家長式領導中的獨裁層面、則會對護士的工作滿足程度產生負面的影響,繼而增強其離職意欲。而且,我們確認了組織支持感是一個會增強工作滿足感與離職意向之間負相聯的條件變數。
研究的局限/啟示
我們以橫斷面的設計法來收集回應,並透過採用哈曼 (Harman) 的單因素檢定法,來確保共同方法變異不會存在。
研究的原創性/價值
本研究確定了一個 (工作滿足感與組織支持感) 機制,透過這機制,家長式領導中的仁慈、道德和獨裁這三個層面可預測於高權力距離文化工作的護士的離職意向。
Details
Keywords
Laura Kauppinen, Petteri Annunen and Harri Haapasalo
Industrialized construction has brought about expectations of improved productivity in the construction industry. However, the lack of a commonly accepted definition has created…
Abstract
Purpose
Industrialized construction has brought about expectations of improved productivity in the construction industry. However, the lack of a commonly accepted definition has created confusion regarding the types of development covered by the industrialized construction umbrella. These inconsistent definitions convoluted the discussion on this phenomenon. This study aims to clarify the definition of industrialized construction through a systematic literature review.
Design/methodology/approach
This systematic literature review was conducted according to PRISMA principles. Records were gathered from Scopus and Web of Science. Following the scientometric analysis, content analysis was conducted according to the template analysis approach.
Findings
The analysis of 121 articles revealed four main themes related to industrialized construction: 1) the construction concept, 2) construction methodologies, 3) systematization, rationalization and automatization and 4) societal and industrial change processes. Definitions of industrialized construction can be analyzed with seven clusters: 1) prefabrication, 2) standardization, 3) sector, 4) integration, 5) manufacturing practices, 6) technological investment and 7) none. Based on the content analysis, the proposed definition is: industrialized construction is the adoption of practices that minimize project-specific work in construction from the start of the design to the end of the building’s life cycle.
Originality/value
This study proposes a definition for industrialized construction following content analysis of broadly sampled literature. The proposed definition can provide a basis on which developments in the construction industry can be reflected.
Details
Keywords
Eveline Maria van Zeeland-van der Holst and Jörg Henseler
The concept of trust suffers from conceptual confusion. The current perspectives on trust within the B2B marketing domain could be visualised as a big box of which the borders are…
Abstract
Purpose
The concept of trust suffers from conceptual confusion. The current perspectives on trust within the B2B marketing domain could be visualised as a big box of which the borders are defined by the disciplines marketing, economics, psychology and sociology. The purpose of this paper is to enlarge the box by introducing neuroscientific insights on trust to the B2B marketing domain.
Design/methodology/approach
By a literature study on neuroscientific insights on trust, this paper examines how neuroscience can help to solve existing problems within trust research and how it can address problems that otherwise might not be considered.
Findings
The neural coordinates of trust not only show that trust entails cognitive and affective elements, but also that these elements are so intertwined that they cannot be completely separated. What can and should be separated are the concepts of trust and distrust: the neural coordinates of trust are clearly different from the neural coordinates of distrust. Furthermore, there are personal differences in the ease of trusting others, which are not only caused by previous experiences but also by differences in resting patterns of frontal electroencephalographic asymmetry and by differences in hormonal state.
Research limitations/implications
Specifically, the neural difference between trust and distrust might shape the future research agenda for trust research within industrial marketing. It is likely that the process of distrust goes quick, whereas trust comes more slow. This is reflected in the dual processing theory, which is seen as a paradigm shift in the psychology of reasoning.
Originality/value
New perspectives and directions for trust research are presented. The distinction between trust and distrust is connected to approach- and avoidance-motivated behaviour, which is highly relevant for deepening the studies on trust within industrial marketing.
Details
Keywords
Olusegun Emmanuel Akinwale and Uche C. Onokala
Crises are moments when citizens are beckoning on the political leaders for necessary action. As a president, one is expected to change the narratives during the pandemic that…
Abstract
Purpose
Crises are moments when citizens are beckoning on the political leaders for necessary action. As a president, one is expected to change the narratives during the pandemic that split the world. This analysis aimed at investigating the American government’s response to the critical crisis of COVID-19 and its policy implementation.
Design/methodology/approach
The study explored a case point method using a narrative and qualitative analysis to diagnose the USA’s response to the COVID-19 crisis. An exploratory approach was further adopted to finetune the case study report.
Findings
The analysis demonstrates that Trump’s power dynamics were weak in the USA and lacked crisis control even as the President that the entire nations of the world were looking up to. The case study report also showed that Trump did not possess the audacity of resilience to manage the crisis. The analysis provides us with how presidential leadership under Trump placed the USA in a state of colossal failure enmeshed with high rates of COVID-19 cases, deaths and unending incapacity to create a fundamental consensus in the fight against the COVID-19 pandemic today. This report shows Trump aged prolonged inability to drive governance mechanisms in the US and illustrated pockets of failures in decision analysis and information dissemination as a leader.
Originality/value
The study revealed how incompetent Trump was in responding to the crisis. This study has provided academia with an understanding of leadership dynamics and behaviour through a Nigerian scholar lens and a sociological perspective.
Details