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Article
Publication date: 22 March 2021

Z.B. Xing, Xingchao Han, Hanbing Ke, Q.G. Zhang, Zhiping Zhang, Huijin Xu and Fuqiang Wang

A combination of highly conductive porous media and nanofluids is an efficient way for improving thermal performance of relevant applications. For precisely predicting the…

Abstract

Purpose

A combination of highly conductive porous media and nanofluids is an efficient way for improving thermal performance of relevant applications. For precisely predicting the flow and thermal transport of nanofluids in porous media, the purpose of this paper is to explore the inter-phase coupling numerical methods.

Design/methodology/approach

Based on the lattice Boltzmann (LB) method, this study combines the convective flow, non-equilibrium thermal transport and phase interactions of nanofluids in porous matrix and proposes a new multi-phase LB model. The micro-scale momentum and heat interactions are especially analyzed for nanoparticles, base fluid and solid matrix. A set of three-phase LB equations for the flow/thermal coupling of base fluid, nanoparticles and solid matrix is established.

Findings

Distributions of nanoparticles, velocities for nanoparticles and the base fluid, temperatures for three phases and interaction forces are analyzed in detail. Influences of parameters on the nanofluid convection in the porous matrix are examined. Thermal resistance of nanofluid convective transport in porous structures are comprehensively discussed with the models of multi-phases. Results show that the Rayleigh number and the Darcy number have significant influences on the convective characteristics. The result with the three-phase model is mildly larger than that with the local thermal non-equilibrium model.

Originality/value

This paper first creates the multi-phase theoretical model for the complex coupling process of nanofluids in porous structures, which is useful for researchers and technicians in fields of thermal science and computational fluid dynamics.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 8 February 2021

Ibrahim A. Amar, Jawaher O. Asser, Amina S. Mady, Mabroukah S. Abdulqadir, Fatima A. Altohami, Abubaker A. Sharif and Ihssin A. Abdalsamed

The main purpose of this paper is to investigate the adsorption properties of CoFe1.9Mo0.1O4 magnetic nanoparticles (CFMo MNPs) using, anionic dye “congo red (CR)” as a…

Abstract

Purpose

The main purpose of this paper is to investigate the adsorption properties of CoFe1.9Mo0.1O4 magnetic nanoparticles (CFMo MNPs) using, anionic dye “congo red (CR)” as a model of water pollutants.

Design/methodology/approach

The magnetic nano-adsorbent was synthesized via sol-gel process. Different techniques including; Fourier transform infrared spectroscopy, point of zero charge, scanning electron microscope and X-ray powder diffraction were used to characterize the prepared adsorbent. Adsorption experiments were conducted in batch mode under various conditions (contact time, shaking speed, initial dye concentration, initial solution pH, solution temperature and adsorbent amount) to investigate the adsorption capability of CFMo MNPs for CR.

Findings

The results showed that, CFMo MNPs could successfully remove more than 90% of CR dye within 20 min. Adsorption kinetics and isotherms were better described using pseudo-second-order (PSO) and Langmuir models, respectively. The maximum adsorbed amount (qmax) of CR dye was 135.14 mg/g. The adsorption process was found to be endothermic and spontaneous in nature as demonstrated by the thermodynamics ( ΔGo, ΔHoand ΔSo).

Practical implications

This study provided a good example of using an easily separated magnetic nano-adsorbent for fast removal of a very toxic organic pollutant, congo red, from the aquatic environment

Originality/value

The employment of Mo-doped cobalt ferrite for the first time for removing hazardous anionic dyes such as congo red from their aqueous solutions.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 12 March 2020

Shekhar Srivastava, Rajiv Kumar Garg, Vishal S. Sharma, Noe Gaudencio Alba-Baena, Anish Sachdeva, Ramesh Chand and Sehijpal Singh

This paper aims to present a systematic approach in the literature survey related to metal additive manufacturing (AM) processes and its multi-physics continuum modelling…

Abstract

Purpose

This paper aims to present a systematic approach in the literature survey related to metal additive manufacturing (AM) processes and its multi-physics continuum modelling approach for its better understanding.

Design/methodology/approach

A systematic review of the literature available in the area of continuum modelling practices adopted for the powder bed fusion (PBF) AM processes for the deposition of powder layer over the substrate along with quantification of residual stress and distortion. Discrete element method (DEM) and finite element method (FEM) approaches have been reviewed for the deposition of powder layer and thermo-mechanical modelling, respectively. Further, thermo-mechanical modelling adopted for the PBF AM process have been discussed in detail with its constituents. Finally, on the basis of prediction through thermo-mechanical models and experimental validation, distortion mitigation/minimisation techniques applied in PBF AM processes have been reviewed to provide a future direction in the field.

Findings

The findings of this paper are the future directions for the implementation and modification of the continuum modelling approaches applied to PBF AM processes. On the basis of the extensive review in the domain, gaps are recommended for future work for the betterment of modelling approach.

Research limitations/implications

This paper is limited to review only the modelling approach adopted by the PBF AM processes, i.e. modelling techniques (DEM approach) used for the deposition of powder layer and macro-models at process scale for the prediction of residual stress and distortion in the component. Modelling of microstructure and grain growth has not been included in this paper.

Originality/value

This paper presents an extensive review of the FEM approach adopted for the prediction of residual stress and distortion in the PBF AM processes which sets the platform for the development of distortion mitigation techniques. An extensive review of distortion mitigation techniques has been presented in the last section of the paper, which has not been reviewed yet.

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Article
Publication date: 19 June 2019

Xixing Li, Baigang Du, Yibing Li and Kejia Zhuang

In practical workshop production process, there are many production emergencies, e.g. new manufacturing tasks, facilities failure and tasks change. On one hand, it results…

Abstract

Purpose

In practical workshop production process, there are many production emergencies, e.g. new manufacturing tasks, facilities failure and tasks change. On one hand, it results in poor timeliness and reliability of real-time production data collection, acquisition and transmission; on the other hand, it increases the difficulty of real-time data tracking and monitoring. This paper aims to develop a novel RFID-based tracking and monitoring approach of real-time data in production workshop (TMrfid) to solve them.

Design/methodology/approach

At first, a three-layer model of real-time data based on RFID has been constructed, which contains RFID-based integrated acquisition center; “RFID & Cloud-service-rules”-based calculation and analysis center; and “RFID & Ontology-knowledge-base”-based monitoring and scheduling center. Then, a targeted analysis and evaluation method of TMrfid with feasibility, quality and performance has been proposed. Finally, a prototype platform of a textile machinery manufacturing enterprise has been built to verify the effective of TMrfid.

Findings

The effectiveness of TMrfid is verified by applying two groups of actual experimental data from the case enterprise, the results show that TMrfid can promote the efficiency, reliability and feasibility of tacking and monitoring of real-time data in production workshop.

Originality/value

RFID-based tracking and monitoring approach of real-time data in production workshop has been developed to solve the data information transmission and sharing problem. Three analysis and evaluation approaches have been introduced to solve the un-standardized evaluation problem of RFID application. A prototype platform of a textile machinery manufacturing enterprise has been constructed.

Details

Assembly Automation, vol. 39 no. 4
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 6 September 2018

Zhen Hong, C.K.M. Lee and Linda Zhang

The purpose of this paper is twofold, first providing researchers with an overview about the uncertainties occurred in procurement including applicable approaches for…

Abstract

Purpose

The purpose of this paper is twofold, first providing researchers with an overview about the uncertainties occurred in procurement including applicable approaches for analyzing different uncertain scenarios, and second proposing directions to inspire future research by identifying research gaps.

Design/methodology/approach

Papers related to supply chain risk management and procurement risk management (PRM) from 1995–2017 in several major databases are extracted by keywords and then further filtered based on the relevance to the topic, number of citations and publication year. A total of over 156 papers are selected. Definitions and current approaches related to procurement risks management are reviewed.

Findings

Five main risks in procurement process are identified. Apart from summarizing current strategies, suggestions are provided to facilitate strategy selection to handle procurement risks. Seven major future challenges and implications related PRM and different uncertainties are also indicated in this paper.

Research limitations/implications

Procurement decisions making under uncertainty has attracted considerable attention from researchers and practitioners. Despite the increasing awareness for risk management for supply chain, no detail and holistic review paper studied on procurement uncertainty. Managing procurement risk not only need to mitigate the risk of price and lead time, but also need to have sophisticated analysis techniques in supply and demand uncertainty.

Originality/value

The contribution of this review paper is to discuss the implications of the research findings and provides insight about future research. A novel research framework is introduced as reference guide for researchers to apply innovative approach of operations research to resolve the procurements uncertainty problems.

Details

Industrial Management & Data Systems, vol. 118 no. 7
Type: Research Article
ISSN: 0263-5577

Keywords

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Article
Publication date: 28 April 2020

Jiang-Tao Wang, Shufen Zhang, Chia-Huei Wu, Jian-Jun Yu, Chang-Bin Chen and Sang-Bing Tsai

This study aims to provide a time- and price-sensitive market strategy for merchants to handle the markdown price strategy. The market demand for perishable products is…

Abstract

Purpose

This study aims to provide a time- and price-sensitive market strategy for merchants to handle the markdown price strategy. The market demand for perishable products is usually price – and quality (freshness) – sensitive. The proper handling of markdown-price strategies can help merchants enhance competitiveness and maximize operational performance.

Design/methodology/approach

A markdown strategy consisting of price and markdown time was developed to explore the properties of market strategies based on the dynamic quality evaluation. The strategy considers multiple price discounts and multiple markdown times. The optimal price decisions in each stage and the optimal markdown times were derived during the selling season.

Findings

The results showed the following. A retailer always raises the initial price if it wants to adopt multiple price-markdown strategies. A high initial price may lead to a high inventory at the early stage and bring the next price reduction in advance. Large price discounts can be used to reduce the inventory later. The higher the previous price, the shorter the interval between the next price reduction. The markdown strategies showed that the regular discount as a new business model is not the best pricing model for perishable products. A time- and price-sensitive strategy, however, can increase operational performance and provide new insights for perishable products.

Originality/value

The results showed the following. A retailer always raises the initial price if it wants to adopt multiple price-markdown strategies. A high initial price may lead to a high inventory at the early stage and bring the next price reduction in advance. Large price discounts can be used to reduce the inventory later. The higher the previous price, the shorter the interval between the next price reduction. The markdown strategies showed that the regular discount as a new business model is not the best pricing model for perishable products. A time- and price-sensitive strategy, however, can increase operational performance and provide new insights for perishable products.

Details

Kybernetes, vol. 50 no. 1
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 18 February 2019

Yang Liu, Hao Zhang, Lingen Wang, Xuejun Fan, Guoqi Zhang and F. Sun

Crack and stress distribution on dies are key issues for the pressure-assisted sintering bonding of power modules. The purpose of this research is to build a relationship…

Abstract

Purpose

Crack and stress distribution on dies are key issues for the pressure-assisted sintering bonding of power modules. The purpose of this research is to build a relationship among stress distributions, sintering sequences and sintering pressures during the sintering processes.

Design/methodology/approach

Three sintering sequences, S(a), S(b) and S(c), have been designed for the double-side assembly of power module in this paper. Experiments and finite element method (FEM) analysis are conducted to investigate the crack and stress distribution.

Findings

The sintering sequence had significant effects on the crack generation in the chips during the sintering process under 30-MPa pressure. The simulation results revealed that the module sintered by S(a) showed lower chip stress than those by the other two sintering sequences under 30 MPa. In contrast, the chip stress is the highest when the sintering sequence follows S(b). The simulation results explained the crack generation and prolongation in the experiments. S(a) was recommended as the best sintering sequence because of the lowest chip stress and highest yield rate.

Originality/value

This study investigated the stress distributions of the double-side sintered power modules under different sintering pressures. Based on the results of experiments and FEM analysis, the best sintering sequence design is provided under various sintering pressures.

Details

Soldering & Surface Mount Technology, vol. 31 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 1 September 2016

Qin Yan and Yin Pan

Planning for underground spaces has become an effective way to use central areas in cities given the steady economic growth in China. The development of underground spaces…

Abstract

Planning for underground spaces has become an effective way to use central areas in cities given the steady economic growth in China. The development of underground spaces in mountainous cities has satisfied the needs of the diversification of the city commercial areas and pedestrian movement. Safety issues exist because these underground spaces were originally used for civil air defense. This study was based on the underground commercial street in Chongqing, which is a typical mountainous city. Based on the results of combined fieldwork and survey, this paper summarized current safety issues, which include the not-fully-open exit, the imbalanced exit location, blocked evacuation routes, and the poor awareness of the potential safety issues. This paper proposed a framework of the safety factors for the underground space and synopsized prevention strategies that are specific to potential disasters in the underground environment. The framework comprises ensuring that the exits are fully open, the underground corridors are kept unblocked, the open space on the street is increased for disaster prevention, and equipment security is maintained and managed. At last, This paper summarized disaster prevention strategies, which include ensuring unimpeded exits, balancing the locations of the exits, avoiding blocks, increasing the disaster prevention square area in the underground space, maintaining and managing the security of the equipment.

Details

Open House International, vol. 41 no. 3
Type: Research Article
ISSN: 0168-2601

Keywords

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Article
Publication date: 2 January 2019

Qinqin Li, Yujie Xiao, Yuzhuo Qiu, Xiaoling Xu and Caichun Chai

The purpose of this paper is to examine the impact of carbon permit allocation rules (grandfathering mechanism and benchmarking mechanism) on incentive contracts provided…

Abstract

Purpose

The purpose of this paper is to examine the impact of carbon permit allocation rules (grandfathering mechanism and benchmarking mechanism) on incentive contracts provided by the retailer to encourage the manufacturer to invest more in reducing carbon emissions.

Design/methodology/approach

The authors consider a two-echelon supply chain in which the retailer offers three contracts (wholesale price contract, cost-sharing contract and revenue-sharing contract) to the manufacturer. Based on the two carbon permit allocation rules, i.e. grandfathering mechanism and benchmarking mechanism, six scenarios are examined. The optimal price and carbon emission reduction decisions and members’ equilibrium profits under six scenarios are analyzed and compared.

Findings

The results suggest that the revenue-sharing contract can more effectively stimulate the manufacturer to reduce carbon emissions compared to the cost-sharing contract. The cost-sharing contract can help to achieve the highest environmental performance, whereas the implementation of revenue-sharing contract can attain the highest social welfare. The benchmarking mechanism is more effective for the government to prompt the manufacturer to produce low-carbon products than the grandfathering mechanism. Although a loose carbon policy can expand the total emissions, it can improve the social welfare.

Practical implications

These results can provide operational insights for the retailer in how to use incentive contract to encourage the manufacturer to curb carbon emissions and offer managerial insights for the government to make policy decisions on carbon permit allocation rules.

Originality/value

This paper contributes to the literature regarding to firm’s carbon emissions reduction decisions under cap-and-trade policy and highlights the importance of carbon permit allocation methods in curbing carbon emissions.

Details

Kybernetes, vol. 49 no. 4
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 3 August 2020

Yichen Qin, Hoi-Lam Ma, Felix T.S. Chan and Waqar Ahmed Khan

This paper aims to build a novel model and approach that assist an aircraft MRO procurement and overhaul management problems from the perspective of aircraft maintenance…

Abstract

Purpose

This paper aims to build a novel model and approach that assist an aircraft MRO procurement and overhaul management problems from the perspective of aircraft maintenance service provider, in order to ensure its smoothness maintenance activities implementation. The mathematical model utilizes the data related to warehouse inventory management, incoming customer service planning as well as risk forecast and control management at the decision-making stage, which facilitates to alleviate the negative impact of the uncertain maintenance demands on the MRO spare parts inventory management operations.

Design/methodology/approach

A stochastic model is proposed to formulate the problem to minimize the impact of uncertain maintenance demands, which provides flexible procurement and overhaul strategies. A Benders decomposition algorithm is proposed to solve large-scale problem instances given the structure of the mathematical model.

Findings

Compared with the default branch-and-bound algorithm, the computational results suggest that the proposed Benders decomposition algorithm increases convergence speed.

Research limitations/implications

The results among the same group of problem instances suggest the robustness of Benders decomposition in tackling instances with different number of stochastic scenarios involved.

Practical implications

Extending the proposed model and algorithm to a decision support system is possible, which utilizes the databases from enterprise's service planning and management information systems.

Originality/value

A novel decision-making model for the integrated rotable and expendable MRO spare parts planning problem under uncertain environment is developed, which is formulated as a two-stage stochastic programming model.

Details

Industrial Management & Data Systems, vol. 120 no. 9
Type: Research Article
ISSN: 0263-5577

Keywords

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