Wei-Chao Yang, Guo-Zhi Li, E Deng, De-Hui Ouyang and Zhi-Peng Lu
Sustainable urban rail transit requires noise barriers. However, these barriers’ durability varies due to the differing aerodynamic impacts they experience. The purpose of this…
Abstract
Purpose
Sustainable urban rail transit requires noise barriers. However, these barriers’ durability varies due to the differing aerodynamic impacts they experience. The purpose of this paper is to investigate the aerodynamic discrepancies of trains when they meet within two types of rectangular noise barriers: fully enclosed (FERNB) and semi-enclosed with vertical plates (SERNBVB). The research also considers the sensitivity of the scale ratio in these scenarios.
Design/methodology/approach
A 1:16 scaled moving model test analyzed spatiotemporal patterns and discrepancies in aerodynamic pressures during train meetings. Three-dimensional computational fluid dynamics models, with scale ratios of 1:1, 1:8 and 1:16, used the improved delayed detached eddy simulation turbulence model and slip grid technique. Comparing scale ratios on aerodynamic pressure discrepancies between the two types of noise barriers and revealing the flow field mechanism were done. The goal is to establish the relationship between aerodynamic pressure at scale and in full scale.
Findings
The aerodynamic pressure on SERNBVB is influenced by the train’s head and tail waves, whereas for FERNB, it is affected by pressure wave and head-tail waves. Notably, SERNBVB's aerodynamic pressure is more sensitive to changes in scale ratio. As the scale ratio decreases, the aerodynamic pressure on the noise barrier gradually increases.
Originality/value
A train-meeting moving model test is conducted within the noise barrier. Comparison of aerodynamic discrepancies during train meets between two types of rectangular noise barriers and the relationship between the scale and the full scale are established considering the modeling scale ratio.
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M. Mahruf C. Shohel, Md. Ashrafuzzaman, Arif Mahmud, Farhan Azim and Md. Shahadat Hossain Khan
The COVID-19 pandemic has dramatically transformed higher education policy and practices across the globe, including Bangladesh. Higher education institutions (HEIs) were forced…
Abstract
The COVID-19 pandemic has dramatically transformed higher education policy and practices across the globe, including Bangladesh. Higher education institutions (HEIs) were forced to deliver teaching and learning online. This chapter discusses the impact of the COVID-19 pandemic on teaching and learning practice in higher education in Bangladesh and highlights the cultural transformation of policy and practice. In addition, it proposes future directions on how to be prepared and addresses the challenges of emergencies and draws implications of the findings beyond the national context. In the beginning of the pandemic, most universities in Bangladesh had to initially shut down their operations without offering any alternatives. However, a number of universities gradually rolled out some online teaching and learning activities as the lockdowns kept extending. A large portion of the HEIs struggled to continue their online teaching and learning due to the lack of resources, i.e., devices, technological skills and training, lack of policy, negative mindset, poor network infrastructure, and high cost of internet. This unprecedented situation ushered in by the pandemic showed the lack of preparedness and below-par capacity to respond to emergencies for the continuation of higher education in Bangladesh. Furthermore, it highlighted that improving the higher education sector requires tremendous effort from the government, researchers, policymakers, practitioners, the universities, and other industries directly or indirectly related to the sector.
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Shyh-Shiuh Chen, Chao Ou-Yang and Tzu-Chuan Chou
The purpose of this paper is to conceptualize how information technology (IT) enables supply chain (SC) network capabilities, which is to capitalize on SC’s existing set of…
Abstract
Purpose
The purpose of this paper is to conceptualize how information technology (IT) enables supply chain (SC) network capabilities, which is to capitalize on SC’s existing set of resources and, at the same time, manage new combinations of SC resources to meet future market needs. The paper also develops SCM framework associated with IT-enabled SC network capabilities.
Design/methodology/approach
Through a case study of a leading Taiwanese petrochemical corporation, qualitative data were gathered on the IT-related SC management practices, in terms of network resource mobilizing and adaptive co-management arrangements to enable SC network capability. This research is based primarily on the interviews of the case company, supplemented by archived documents, published books, and in-depth observations.
Findings
Based on the evidence from the case, this study inductively develops a model that includes the operating processes with IT-enabled activities to achieve ambidextrous SC network capability, and the relevant framework functions in network resources and co-management activities include information co-governance, information interoperability, community engagement strategy, cyber-physical dexterity, and control enactment, which lead the SC alliances improvements for dynamic environmental changes.
Practical implications
Practitioners may derive strategies and tactics from the current findings to help them implement innovative information technologies and setup SC framework, during SC network capability development, to achieve SC’s sustainable competence in a dynamic market.
Originality/value
Researchers and practitioners may obtain a more complete view of IT-enabled SC network capability development. The proposed model reveals that developing IT-enabled SC network capabilities is a dynamic process whereby an organization’s major SC managerial activities are divided into specific network resource mobilizing and adaptive co-management arrangements.
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Xiaojie Xu and Yun Zhang
Forecasts of commodity prices are vital issues to market participants and policy makers. Those of corn are of no exception, considering its strategic importance. In the present…
Abstract
Purpose
Forecasts of commodity prices are vital issues to market participants and policy makers. Those of corn are of no exception, considering its strategic importance. In the present study, the authors assess the forecast problem for the weekly wholesale price index of yellow corn in China during January 1, 2010–January 10, 2020 period.
Design/methodology/approach
The authors employ the nonlinear auto-regressive neural network as the forecast tool and evaluate forecast performance of different model settings over algorithms, delays, hidden neurons and data splitting ratios in arriving at the final model.
Findings
The final model is relatively simple and leads to accurate and stable results. Particularly, it generates relative root mean square errors of 1.05%, 1.08% and 1.03% for training, validation and testing, respectively.
Originality/value
Through the analysis, the study shows usefulness of the neural network technique for commodity price forecasts. The results might serve as technical forecasts on a standalone basis or be combined with other fundamental forecasts for perspectives of price trends and corresponding policy analysis.
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This paper aims to explore the feasibility of using web‐mining technology on learning object (LO) usage information to discover the LO relation pattern and provide valuable…
Abstract
Purpose
This paper aims to explore the feasibility of using web‐mining technology on learning object (LO) usage information to discover the LO relation pattern and provide valuable recommendations on related learning resources. Design/methodology/approach – This paper proposes three kinds of learning object relation patterns and gives a specific definition of each pattern based on analysing the learners' usage data stored in the learning object repository. These relation patterns can be used to make effective recommendations to learners.
Findings
LO usage data indicate the potential relation patterns between LOs. By using web‐mining technology on the usage data, it is possible to discover valuable relation patterns.
Originality/value
The authors propose a set of LO relation patterns and indicate how they are closely related to users' learning behaviour.
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Jiawang Zeng, Ming-Zhi Yang, Lei Zhang, Tongtong Lin, Sha Zhong and Yu Tao
The aerodynamic load caused by high-speed train operation may lead to severe vibration of the pedestrian bridge, thus causing great safety hazards. Therefore, this study aims to…
Abstract
Purpose
The aerodynamic load caused by high-speed train operation may lead to severe vibration of the pedestrian bridge, thus causing great safety hazards. Therefore, this study aims to investigate the aerodynamic loading characteristics of a pedestrian bridge when a high-speed train passes over the bridge, as well as to evaluate the vibration response of the aerodynamic loads on the bridge structure.
Design/methodology/approach
High-speed trains are operated at three different speeds. The aerodynamic pressure load characteristics of high-speed trains crossing a pedestrian bridge are investigated by combining a nonconstant numerical simulation method with a dynamic modeling test method, and the vibration response of the bridge is analyzed.
Findings
The results show that when a high-speed train passes through the pedestrian bridge, the pedestrian bridge interferes with the attenuation of the pressure around the train, so that the pressure spreads along the bridge bottom, and the maximum positive and negative pressure peaks appear in the center area of the bridge bottom, while the pressure fluctuations in the bridge entrance and exit areas are smaller and change more slowly, and the pressure attenuation of the bridge bottom perpendicular to the direction of the train’s operation is faster. In addition, the pressure fluctuation generated by the high-speed train will lead to a larger vertical response of the bridge structure in the mid-span position, and the main vibration frequency of the bridge structure ranges from 8 to 10 Hz, and the maximum value of the vertical deformation amplitude is located in the mid-span region of the bridge.
Originality/value
This paper analyzes the flow field distribution around the train and at the bottom of the bridge for the evolution of the flow field when the train passes through the bridge at high speed, and conducts a finite element dynamic analysis of the bridge structure to calculate the vibration response of the bridge when the train passes through at high speed, and to evaluate the comfort of the passengers passing through the high-speed railroad bridge.
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Jian Wei, XiaoYue Sun, Jing Tian and CaiHong Liu
This paper aims to study the impact of transient velocity changes on sealing performance during reciprocating sealing processes.
Abstract
Purpose
This paper aims to study the impact of transient velocity changes on sealing performance during reciprocating sealing processes.
Design/methodology/approach
Establish a model of transient mixed lubrication, solve the transient Reynolds equation, consider the effect of temperature rise at the seal interfaces, and determine the behavior of the seal interfaces, such as film thickness and fluid pressure. Evaluation with friction and leakage rate, calculate the variation of sealing performance with reciprocating velocity under different working conditions, and verify it through bench experiments.
Findings
Within a reciprocating stroke, the frictional force decreases with increasing velocity, and the frictional force of the outstroke is greater than that of the instroke; at the time of the stroke transition, the fluid pressure is smallest and the rough peak contact pressure is greatest. At present, the dynamic pressure effect of fluids is the largest, and the friction force also increases, which increases the risk of material wear and failure. Friction and leakage increase with increasing pressure and root mean square roughness. As temperature increases, friction increases and leakage decreases. In studying the performance variations of seal components through a reciprocating sealing experiment, it was found that the friction force decreases with increasing velocity, which is consistent with the calculated results and more similar to the calculated results considering the temperature rise.
Originality/value
This study provides a reference for the study of transient sealing performance.
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Xiuli Zhang, Wenkai Gao, Jian Cui, Yuankang Shen, Tao Huang, Gengyuan Gao and Jun Cao
Rubber-plastic double-layer bush water-lubricated bearings have demonstrated superior performance, while research on their vibration characteristics remains limited. This paper…
Abstract
Purpose
Rubber-plastic double-layer bush water-lubricated bearings have demonstrated superior performance, while research on their vibration characteristics remains limited. This paper aims to investigate the lubrication and vibration properties of these bearings by experiments and examine the effect of rubber-to-plastic bush thickness ratio on bearing performance.
Design/methodology/approach
A water-lubricated journal bearing test rig is constructed, and three bearings with different bush thickness ratios are fabricated. Bush deformation under various loads is measured, and the friction coefficient and axis trajectory under different operating conditions are tested. The vibration responses of the bearings under directional harmonic excitation are studied. The influences of rotational speed, load and rubber-to-plastic bush thickness ratio on the bearing’s lubrication and vibration properties are analyzed.
Findings
The friction coefficient of the bearing initially decreases rapidly and subsequently increases gradually as the rotational speed or load increases. The bearing with a thicker rubber bush shows lower displacement amplitudes in its axis trajectory. Under a 45° directed excitation, significant oscillations are observed in the vertical displacement, while the horizontal displacement remains stable. The damping effect of the bearing with a thicker rubber bush is more pronounced.
Originality/value
This paper present the influence of rubber-to-plastic bush thickness ratio on bearing lubrication and vibration performance. The results are valuable for the design of this type of bearing.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2024-0469/
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Mariya Shygun, Liubov Gutsalenko and Uliana Marchuk
Introduction: Today, with uncertainty and negative environmental and human health changes, achieving the global goals of sustainable development is becoming extremely important…
Abstract
Introduction: Today, with uncertainty and negative environmental and human health changes, achieving the global goals of sustainable development is becoming extremely important. The experience of reforming the medical sector in Ukraine can be helpful to the countries that are developing and implementing reform processes in the medical field to achieve the goals of sustainable development.
Purpose: Reformation processes are caused by changes in the medical sector financing model due to the introduction of state solidarity health insurance.
Methodology: The research shows changes in the role of the state and local authorities in the healthcare system. It also reveals how the medical reform creates conditions for attracting private investments, stimulating the financing of primary healthcare, and opening a self-financing secondary healthcare sector. Special features of the reform in Ukraine are the transformation healthcare facility management’s accounting and information support system and the transition from accounting and reporting standards for the public sector to accounting standards for the private sector.
Findings: The authors describe how introducing a two-tier electronic healthcare system (eHealth), which functions as a state central database and solutions of the medical information system, can provide comprehensive informatization of healthcare facilities and automation of medical and administrative workplaces.
Practical implications: The innovations introduced in Ukraine should create an environment for rationalizing medical healthcare and promote the effective functioning of public and private healthcare facilities.
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The purpose of this guest editorial is to introduce the papers in this special issue.
Abstract
Purpose
The purpose of this guest editorial is to introduce the papers in this special issue.
Design/methodology/approach
A brief introduction about the issue of web‐mining applications in e‐commerce and e‐services is provided, along with a summary of the main contributions of the papers that are included in the special issue.
Findings
The value of web‐mining techniques can be enhanced through applying them to real environments such as e‐commerce and e‐services. The research fields of web mining, e‐commerce and e‐services can also be expanded.
Originality/value
An overview of the special issue and related research is provided in this paper.