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Open Access
Article
Publication date: 1 July 2021

Sarfaraz Kamangar, N. Ameer Ahamad, N. Nik-Ghazali, Ali E. Anqi, Ali Algahtani, C. Ahamed Saleel, Syed Javed, Vineet Tirth and T.M. Yunus Khan

Coronary artery disease (CAD) is reported as one of the most common sources of death all over the world. The presence of stenosis (plaque) in the coronary arteries results in the…

Abstract

Purpose

Coronary artery disease (CAD) is reported as one of the most common sources of death all over the world. The presence of stenosis (plaque) in the coronary arteries results in the restriction of blood supply, leading to myocardial infarction. The current study investigates the influence of multi stenosis on hemodynamic properties in a patient-specific left coronary artery.

Design/methodology/approach

A three-dimensional model of the patient-specific left coronary artery was reconstructed based on computed tomography (CT) scan images using MIMICS-20 software. The diseased model of the left coronary artery was investigated, having the narrowing of 90% and 70% of area stenosis (AS) at the left anterior descending (LAD) and left circumflex (LCX), respectively.

Findings

The results indicate that the upstream region of stenosis experiences very high pressure for 90% AS during the systolic period of the cardiac cycle. The pressure drops maximum as the flow travels into the stenotic zone, and the high flow velocities were observed across the 90% AS. The higher wall shear stresses occur at the stenosis region, and it increases with the increase in the flow rate. It is found that the maximum wall shear stress across 90% AS is at the highest risk for rupture. A recirculation region immediately after the stenosis results in the further development of stenosis.

Originality/value

The current study provides evidence that there is a strong effect of multi-stenosis on the blood flow in the left coronary artery.

Details

Frontiers in Engineering and Built Environment, vol. 1 no. 1
Type: Research Article
ISSN: 2634-2499

Keywords

Article
Publication date: 9 June 2021

Nur Husnina Saadun, Nurul Aini Jaafar, Md Faisal Md Basir, Ali Anqi and Mohammad Reza Safaei

The purpose of this study is to solve convective diffusion equation analytically by considering appropriate boundary conditions and using the Taylor-Aris method to determine the…

Abstract

Purpose

The purpose of this study is to solve convective diffusion equation analytically by considering appropriate boundary conditions and using the Taylor-Aris method to determine the solute concentration, the effective and relative axial diffusivities.

Design/methodology/approach

>An analysis has been conducted on how body acceleration affects the dispersion of a solute in blood flow, which is known as a Bingham fluid, within an artery. To solve the system of differential equations analytically while validating the target boundary conditions, the blood velocity is obtained.

Findings

The blood velocity is impacted by the presence of body acceleration, as well as the yield stress associated with Casson fluid and as such, the process of dispersing the solute is distracted. It graphically illustrates how the blood velocity and the process of solute dispersion are affected by various factors, including the amplitude and lead angle of body acceleration, the yield stress, the gradient of pressure and the Peclet number.

Originality/value

It is witnessed that the blood velocity, the solute concentration and also the effective and relative axial diffusivities experience a drop when either of the amplitude, lead angle or the yield stress rises.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 24 February 2021

Wu Zhao, Anqi Wang, Yun Chen and Wei Liu

Entrepreneurial ecosystem is a frontier issue in the field of enterprise strategy and entrepreneurship. As suggested by bottom of the pyramid (BOP) theory, entrepreneurs from base…

1317

Abstract

Purpose

Entrepreneurial ecosystem is a frontier issue in the field of enterprise strategy and entrepreneurship. As suggested by bottom of the pyramid (BOP) theory, entrepreneurs from base of the pyramid can gain the benefits of economic growth by obtaining equal entrepreneurial opportunities with appropriate support and motivation. However, theoretical framework to understand the ecosystem and help the people from the BOP to benefit from ecosystem is under-researched. Based on the investigation of the Taobao ecosystem case study, this paper developed a multi-layer framework to fill in the research gap.

Design/methodology/approach

This research adopts case study methodology for several reasons. First, case study methodology fits the explorative nature of this research to understand “what” and “how” a phenomenon happened (Yin, 2017). Second, case study research design can specify gaps or holes in existing theory with the ultimate goal of advancing theoretical explanations (Ridder, 2016). And third, it can provide researchers with contextual richness (Davison and Martinsons, 2016; Spigel, 2017).

Findings

Based on the literature review of the entrepreneurial ecosystem and the theory of the BOP, the initial framework of the inclusive entrepreneurial ecosystem is proposed. And then, based on the investigation of the Taobao village which is the typical inclusive entrepreneurial ecosystem, this paper explored how the inclusive entrepreneurial ecosystem emerges, develops and realises the co-creation between multiple actors. The emergence of Taobao village entrepreneurial ecosystem is because of the fact that ICT empowers BOP entrepreneurs. The development of entrepreneurial ecosystem presents a point-line-plane diffusion path, and co-creation to enhance inclusive entrepreneurship is realised by interaction and cooperation within social networks and integration of resources. Then, the framework of inclusive entrepreneurial ecosystem is further modified.

Research limitations/implications

The complexity of entrepreneurial ecosystem facing BOP poses a major challenge to its actual operation. Therefore, it is necessary to study the driving factors of inclusive entrepreneurial ecosystems. In particular, ecosystem is a purposeful collaborative network of dynamic interactive systems, which has a set of changing dependencies in a given context. Research is still limited on socioeconomic actors’ interaction with each other in each stage to promote the evolution of entrepreneurial ecosystem. The extent to which they are intentionally designed or organically produced is still unclear, which is recommended for future study in this field.

Practical implications

It provides theoretical understanding on how to successfully form sustainable entrepreneurial ecosystem by integrating BOP entrepreneurs in value chain. The successful experience of Taobao village can provide contributions and implications for the management in practice. On the one hand, this can provide theoretical guidance for other countries and regions to build inclusive entrepreneurship ecosystems and help them to check and fill the gaps and build inclusive entrepreneurship ecosystems based on their local characteristics. On the other hand, this study provides theoretical guidance for solving the problem of poverty at the BOP, transforming the poor from the objects of help to successful entrepreneurs and thus realising regional sustainable development.

Originality/value

The significance of this study is to provide theoretical understanding on how to successfully form entrepreneurial ecosystem by practical investigation of entrepreneurial “habitat” at the BOP.

Details

Chinese Management Studies, vol. 15 no. 3
Type: Research Article
ISSN: 1750-614X

Keywords

Open Access
Article
Publication date: 25 June 2019

Anqi Xiong and Ali N. Akansu

Transaction cost becomes significant when one holds many securities in a large portfolio where capital allocations are frequently rebalanced due to variations in non-stationary…

Abstract

Purpose

Transaction cost becomes significant when one holds many securities in a large portfolio where capital allocations are frequently rebalanced due to variations in non-stationary statistical characteristics of the asset returns. The purpose of this paper is to employ a sparsing method to sparse the eigenportfolios, so that the transaction cost can be reduced and without any loss of its performance.

Design/methodology/approach

In this paper, the authors have designed pdf-optimized mid-tread Lloyd-Max quantizers based on the distribution of each eigenportfolio, and then employed them to sparse the eigenportfolios, so those small size orders may usually be ignored (sparsed), as the result, the trading costs have been reduced.

Findings

The authors find that the sparsing technique addressed in this paper is methodic, easy to implement for large size portfolios and it offers significant reduction in transaction cost without any loss of performance.

Originality/value

In this paper, the authors investigated the performance the sparsed eigenportfolios of stock returns in S&P500 Index. It is shown that the sparsing method is simple to implement and it provides high levels of sparsity without causing PNL loss. Therefore, transaction cost of managing a large size portfolio is reduced by employing such an efficient sparsity method.

Article
Publication date: 22 July 2022

Lei Hou, Lu Guan, Yixin Zhou, Anqi Shen, Wei Wang, Ang Luo, Heng Lu and Jonathan J.H. Zhu

User-generated content (UGC) refers to semantic and behavioral traces created by users on various social media platforms. While several waves of platforms have come and gone, the…

Abstract

Purpose

User-generated content (UGC) refers to semantic and behavioral traces created by users on various social media platforms. While several waves of platforms have come and gone, the long-term sustainability of UGC activities has become a critical question that bears significance for theoretical understanding and social media practices.

Design/methodology/approach

Based on a large and lengthy dataset of both blogging and microblogging activities of the same set of users, a multistate survival analysis was applied to explore the patterns of users' staying, switching and multiplatforming behaviors, as well as the underlying driving factors.

Findings

UGC activities are generally unsustainable in the long run, and natural attrition is the primary reason, rather than competitive switching to new platforms. The availability of leisure time, expected gratification and previous experiences drive users' sustainability.

Originality/value

The authors adopted actual behavioral data from two generations of platforms instead of survey data on users' switching intentions. Four types of users are defined: loyal, switcher, multiplatformer and dropout. As measured by the transitions among the four states, the different sustainability behaviors are thereby studied via an integrated framework. These two originalities bridge gaps in the literature and offer new insights into exploring user sustainability in social media.

Open Access
Article
Publication date: 18 July 2019

Güler Aras

290

Abstract

Details

Journal of Capital Markets Studies, vol. 3 no. 1
Type: Research Article
ISSN: 2514-4774

Article
Publication date: 12 July 2024

Abdulaziz Alsenafi, Fares Alazemi and M. Nawaz

To improve the thermal performance of base fluid, nanoparticles of three types are dispersed in the base fluid. A novel theory of non-Fourier heat transfer is used for design and…

Abstract

Purpose

To improve the thermal performance of base fluid, nanoparticles of three types are dispersed in the base fluid. A novel theory of non-Fourier heat transfer is used for design and development of models. The thermal performance of sample fluids is compared to determine which types of combination of nanoparticles are the best for an optimized enhancement in thermal performance of fluids. This article aims to: (i) investigate the impact of nanoparticles on thermal performance; and (ii) implement the Galerkin finite element method (GFEM) to thermal problems.

Design/methodology/approach

The mathematical models are developed using novel non-Fourier heat flux theory, conservation laws of computational fluid dynamics (CFD) and no-slip thermal boundary conditions. The models are approximated using thermal boundary layer approximations, and transformed models are solved numerically using GFEM. A grid-sensitivity test is performed. The accuracy, correction and stability of solutions is ensured. The numerical method adopted for the calculations is validated with published data. Quantities of engineering interest, i.e. wall shear stress, wall mass flow rate and wall heat flux, are calculated and examined versus emerging rheological parameters and thermal relaxation time.

Findings

The thermal relaxation time measures the ability of a fluid to restore its original thermal state, called thermal equilibrium and therefore, simulations have shown that the thermal relaxation time associated with a mono nanofluid has the most substantial effect on the temperature of fluid, whereas a ternary nanofluid has the smallest thermal relaxation time. A ternary nanofluid has a wider thermal boundary thickness in comparison with base and di- and mono nanofluids. The wall heat flux (in the case of the ternary nanofluids) has the most significant value compared with the wall shear stresses for the mono and hybrid nanofluids. The wall heat and mass fluxes have the highest values for the case of non-Fourier heat and mass diffusion compared to the case of Fourier heat and mass transfer.

Originality/value

An extensive literature review reveals that no study has considered thermal and concentration memory effects on transport mechanisms in fluids of cross-rheological liquid using novel theory of heat and mass [presented by Cattaneo (Cattaneo, 1958) and Christov (Christov, 2009)] so far. Moreover, the finite element method for coupled and nonlinear CFD problems has not been implemented so far. To the best of the authors’ knowledge for the first time, the dynamics of wall heat flow rate and mass flow rate under simultaneous effects of thermal and solute relaxation times, Ohmic dissipation and first-order chemical reactions are studied.

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

Article
Publication date: 14 July 2020

Mohd Seraj, Syed Mohd Yahya, Mohd Anas, Agung Sutrisno and Mohammad Asjad

In the present study, the thermal performance of engine radiator using conventional coolant and nanofluid is determined experimentally for the different flow rates. Further, the…

Abstract

Purpose

In the present study, the thermal performance of engine radiator using conventional coolant and nanofluid is determined experimentally for the different flow rates. Further, the study implemented the Integrated Taguchi-GRA-PCA for optimising the heat transfer performance.

Design/methodology/approach

Nanofluids were prepared by taking ethylene glycol and water (25:75 by volume) with volume fraction of 0.01, 0.03 and 0.05% of TiO2 nanopowder. Experimental Data were collected based on the design of experiments (DOE) L9 orthogonal array using Taguchi method. Statistical analysis via Grey relation analysis (GRA) and principal component analysis (PCA) were done to determine the role of experimental parameters on heat transfer coefficient and rate of heat transfer. Impact of three control factors, vol. % of TiO2 concentration (φ), flow rate (LPH), and sonication time (min) on the performance characteristics on heat transfer coefficient and ratio of heat transfer rate is analysed to get the best combination of the parameters involved.

Findings

Analysis revealed the importance of parameters on heat transfer coefficient and can be sorted in terms of contributions from higher to lower degree. Finally, ANOVA test has been conducted to validate the effect of process parameters. The major controllable parameter is φ (concentration), contributing about 32.74%, then flow rate contributing 32.5% and finally sonication time showing small contribution of 18.57%.

Originality/value

A grey relational analysis integrated with principal component analyses (PCA) are implemented to get the optimum heat transfer coefficient and ratio of heat transfer rate. The novelty of the work is to adopt and implement the Integrated Taguchi-GRA-PCA first time for the purpose of thermal performance analysis of engine nano-coolant for radiator.

Details

Grey Systems: Theory and Application, vol. 11 no. 1
Type: Research Article
ISSN: 2043-9377

Keywords

Article
Publication date: 12 April 2023

Agung Sutrisno, Cynthia Erlita Virgin Wuisang and Ade Yusupa

The regular occurrence of natural disasters elevates the need for an effective method to measure organizational preparedness in responding to the adverse impact of disasters. In…

Abstract

Purpose

The regular occurrence of natural disasters elevates the need for an effective method to measure organizational preparedness in responding to the adverse impact of disasters. In this context, this paper presents a new decision support model to assess organizational disaster preparedness using both subjective and objective disaster preparedness criteria in a multi-criteria decision-making context.

Design/methodology/approach

The statistical variance method is integrated with the proximity value index (PVI) technique to determine priority scores in order to rank organizational disaster readiness.

Findings

The results of applying the integrated model developed herein enable decision-makers to make informed decisions for assigning priority ranking of organizational disaster preparedness in a simpler and more efficient way.

Research limitations/implications

Human resource is the most impacting criterion affecting hospital preparedness in undertaking action to cure disaster victims.

Practical implications

This paper offers an exemplar of a simple and efficient decision-making process considering the subjectivity associated with decision-making as well as the objectivity of data used for determining the priority ranking of organizational disaster preparedness.

Originality/value

Integrating statistical variance method with the PVI technique is novel and it has not been presented in previous studies. In fact, this study is the first to integrate both methods for selecting the priority ranking of organizational disaster preparedness.

Details

International Journal of Emergency Services, vol. 12 no. 2
Type: Research Article
ISSN: 2047-0894

Keywords

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