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1 – 10 of 24Effiezal Aswadi Abdul Wahab, Anwar Allah Pitchay and Ruhani Ali
The purpose of this paper is to examine the relationship between Bumiputra (in reference to Malay indigenous race) directors, a proxy for culture and analysts forecast. In…
Abstract
Purpose
The purpose of this paper is to examine the relationship between Bumiputra (in reference to Malay indigenous race) directors, a proxy for culture and analysts forecast. In addition, the study investigates whether corporate governance affects that relationship.
Design/methodology/approach
The sample of this study is based on 664 firm-year observations from 193 firms during the 1999-2009 periods. The authors employ a panel least square regression with both period and industry fixed effects. The authors retrieved of analyst data from the Institutional Broker Estimate System (I/B/E/S) database while the authors hand collected the corporate governance variables. The remaining data were collected from Compustat Global.
Findings
The authors find a positive relationship between the proxy of culture, Bumiputra directors and analysts forecast error suggesting that cultural values influences the level of information in the Malaysian capital market.
Research limitations/implications
The research is dependent on the data availability from I/B/E/S database.
Originality/value
The authors extend the work of Haniffa and Cooke (2002) in investigating how cultural values influence the capital market. In addition, this is the first study that investigates culture values and the analysts forecast.
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Fatima Ruhani and Mohd Zukime Mat Junoh
This study aims to find the relationship of stock market returns and selected financial market variables (market capitalization, earnings per share, price-earnings multiples…
Abstract
Purpose
This study aims to find the relationship of stock market returns and selected financial market variables (market capitalization, earnings per share, price-earnings multiples, dividend yield and trading volume) of Malaysia grounded by the arbitrage pricing theories.
Design/methodology/approach
This study empirically examines the effects of selected financial market variables on stock market returns using 64 companies listed in Malaysia's stock market with data spanning from 2005 to 2018. A systematic empirical study based on the Generalized Method of Moments following Arellano and Bond (1991) has been taken to estimate the effect.
Findings
The regression result of the financial market variables and stock market return shows that, except for trading volume, all selected financial market variables play significant roles in the stock market returns. Furthermore, market capitalization, earnings per share, price-earnings ratio, dividend yield and trading volume have a positive impact on stock market returns.
Research limitations/implications
The outcome of this study can contribute by helping domestic and global investors devise strategies to minimize their risks. Also, policy administrators can use the outcomes of this study to inform the micro- and macro-level policy formulation.
Originality/value
This study will contribute to filling the gap in knowledge concerning the new release of factors affecting the stock market returns of Malaysia.
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Syed Alamdar Ali Shah, Bayu Arie Fianto, Batool Imtiaz, Raditya Sukmana and Rafiatul Adlin Hj Mohd Ruslan
The purpose of this paper is to perform Shariah review of Brownian motion that is used for prediction of Islamic stock prices and their volatility.
Abstract
Purpose
The purpose of this paper is to perform Shariah review of Brownian motion that is used for prediction of Islamic stock prices and their volatility.
Design/methodology/approach
It uses the Shariah compliant development model guidelines to review the Brownian motion and its applications.
Findings
The model of Brownian motion does not involve any variable that renders it non-Shariah compliant; neither all applications of Brownian motion are Shariah compliant. Because the model is based on stochastic properties that involve randomness, therefore the issue of gharar takes the utmost important to handle in the applications of the model. The results need to be analyzed strictly in accordance with the Shariah whether they create any element of gharar or uncertainty in case of expected price and volatility estimates.
Research limitations/implications
The research suffers from the limitation that it analyses only one model of physics, i.e. Brownian motion model from Shariah perspective.
Practical implications
The research opens an area for Shariah analysis of results generated from the application of advanced models of physics on matters related to Islamic financial markets.
Originality/value
The originality of this study stems from the fact that to the best of the authors’ knowledge, it is the first study that extends Shariah guidelines into Financial physics for making the foundations of Islamic econophysics.
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Mahantesh M. Nandeppanavar, T. Srinivasulu and Shanker Bandari
The purpose of this paper is to study the flow, heat and mass transfer of MHD Casson nanofluid due to an inclined stretching sheet using similarity transformation, the governing…
Abstract
Purpose
The purpose of this paper is to study the flow, heat and mass transfer of MHD Casson nanofluid due to an inclined stretching sheet using similarity transformation, the governing PDE’S equations of flow, heat and mass transfer are converted into ODE’S. The resulting non-linear ODE’S are solved numerically using an implicit finite difference method, which is known as Kellor-box method. The effects of various governing parameters on velocity, temperature and concentration are plotted for both Newtonian and non-Newtonian cases. The numerical values of skin friction, Nusselt number and Sherwood number are calculated and tabulated in various tables for different values of physical parameters. It is noticed that the effect of angle of inclination enhances the temperature and concentration profile whereas velocity decreases. The temperature decreases due to the increase in the parametric values of Pr and Gr due to thickening in the boundary layer.
Design/methodology/approach
Numerical method is applied to find the results.
Findings
Flow and heat transfer analysis w.r.t various flow and temperature are analyzed for different values of the physical parameters.
Research limitations/implications
The numerical values of skin friction, Nusselt number and Sherwood number are calculated and tabulated in various tables for different values of physical parameters.
Practical implications
The study of the boundary layer flow, heat and mass transfer is important due to its applications in industries and many manufacturing processes such as aerodynamic extrusion of plastic sheets and cooling of metallic sheets in a cooling bath.
Originality/value
Here in this paper the authors have investigated the MHD boundary layer flow of a Casson nanofluid over an inclined stretching sheet along with the Newtonian nanofluid as a limited.
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Seyed Mohammad Mousavi, Omid Ali Akbari, Ghanbarali Sheikhzadeh, Ali Marzban, Davood Toghraie and Ali J. Chamkha
The purpose of this study is two phase modeling of Water/Cu nanofluid forced convection in different arrangements of elliptical tube banks in a two-dimensional space.
Abstract
Purpose
The purpose of this study is two phase modeling of Water/Cu nanofluid forced convection in different arrangements of elliptical tube banks in a two-dimensional space.
Design/methodology/approach
The arrangements of tube banks have been regarded as equal spacing triangle (ES), equilateral triangle (ET) and the rotated square (RS). The obtained results indicate that, among the investigated arrangements, the RS arrangement has the maximum value of heat transfer with cooling fluid. Also, the changes of Nusselt number and the local friction factor are under the influence of three main factors including volume fraction of slid nanoparticles, the changes of fluid velocity parameters on the curved surface of tube and flow separation after crossing from a specified angle of fluid rotation.
Findings
In Reynolds number of 250 and in all arrangements of the tube banks, the behavior of Nusselt number is almost the same and the separation of flow happens in almost 155-165 degrees from fluid rotation on surface. In RS arrangement, due to the strength of vortexes after fluid separation, better mixture is created and because of this reason, after the separation zone, the level of local Nusselt number graph enhances significantly.
Originality/value
In this research, the laminar and two-phase flow of Water/Cu nanofluid in tube banks with elliptical cross section has been numerically investigated in a two-dimensional space with different longitudinal arrangements. In this study, the effects of using nanofluid, different arrangements of tube banks and the elliptical cross section on heat transfer and cooling fluid flow among the tube banks of heat exchanger have been numerically simulated by using finite volume method.
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Ali Rahimi Gheynani, Omid Ali Akbari, Majid Zarringhalam, Gholamreza Ahmadi Sheikh Shabani, Abdulwahab A. Alnaqi, Marjan Goodarzi and Davood Toghraie
Although many studies have been conducted on the nanofluid flow in microtubes, this paper, for the first time, aims to investigate the effects of nanoparticle diameter and…
Abstract
Purpose
Although many studies have been conducted on the nanofluid flow in microtubes, this paper, for the first time, aims to investigate the effects of nanoparticle diameter and concentration on the velocity and temperature fields of turbulent non-Newtonian Carboxymethylcellulose (CMC)/copper oxide (CuO) nanofluid in a three-dimensional microtube. Modeling has been done using low- and high-Reynolds turbulent models. CMC/CuO was modeled using power law non-Newtonian model. The authors obtained interesting results, which can be helpful for engineers and researchers that work on cooling of electronic devices such as LED, VLSI circuits and MEMS, as well as similar devices.
Design/methodology/approach
Present numerical simulation was performed with finite volume method. For obtaining higher accuracy in the numerical solving procedure, second-order upwind discretization and SIMPLEC algorithm were used. For all Reynolds numbers and volume fractions, a maximum residual of 10−6 is considered for saving computer memory usage and the time for the numerical solving procedure.
Findings
In constant Reynolds number and by decreasing the diameter of nanoparticles, the convection heat transfer coefficient increases. In Reynolds numbers of 2,500, 4,500 and 6,000, using nanoparticles with the diameter of 25 nm compared with 50 nm causes 0.34 per cent enhancement of convection heat transfer coefficient and Nusselt number. Also, in Reynolds number of 2,500, by increasing the concentration of nanoparticles with the diameter of 25 nm from 0.5 to 1 per cent, the average Nusselt number increases by almost 0.1 per cent. Similarly, In Reynolds numbers of 4,500 and 6,000, the average Nusselt number increases by 1.8 per cent.
Research limitations/implications
The numerical simulation was carried out for three nanoparticle diameters of 25, 50 and 100 nm with three Reynolds numbers of 2,500, 4,500 and 6,000. Constant heat flux is on the channel, and the inlet fluid becomes heated and exists from it.
Practical implications
The authors obtained interesting results, which can be helpful for engineers and researchers that work on cooling of electronic devices such as LED, VLSI circuits and MEMS, as well as similar devices.
Originality/value
This manuscript is an original work, has not been published and is not under consideration for publication elsewhere. About the competing interests, the authors declare that they have no competing interests.
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Mohammed Ayoub Ledhem and Warda Moussaoui
This paper aims to apply several data mining techniques for predicting the daily precision improvement of Jakarta Islamic Index (JKII) prices based on big data of symmetric…
Abstract
Purpose
This paper aims to apply several data mining techniques for predicting the daily precision improvement of Jakarta Islamic Index (JKII) prices based on big data of symmetric volatility in Indonesia’s Islamic stock market.
Design/methodology/approach
This research uses big data mining techniques to predict daily precision improvement of JKII prices by applying the AdaBoost, K-nearest neighbor, random forest and artificial neural networks. This research uses big data with symmetric volatility as inputs in the predicting model, whereas the closing prices of JKII were used as the target outputs of daily precision improvement. For choosing the optimal prediction performance according to the criteria of the lowest prediction errors, this research uses four metrics of mean absolute error, mean squared error, root mean squared error and R-squared.
Findings
The experimental results determine that the optimal technique for predicting the daily precision improvement of the JKII prices in Indonesia’s Islamic stock market is the AdaBoost technique, which generates the optimal predicting performance with the lowest prediction errors, and provides the optimum knowledge from the big data of symmetric volatility in Indonesia’s Islamic stock market. In addition, the random forest technique is also considered another robust technique in predicting the daily precision improvement of the JKII prices as it delivers closer values to the optimal performance of the AdaBoost technique.
Practical implications
This research is filling the literature gap of the absence of using big data mining techniques in the prediction process of Islamic stock markets by delivering new operational techniques for predicting the daily stock precision improvement. Also, it helps investors to manage the optimal portfolios and to decrease the risk of trading in global Islamic stock markets based on using big data mining of symmetric volatility.
Originality/value
This research is a pioneer in using big data mining of symmetric volatility in the prediction of an Islamic stock market index.
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Navid Ahmadi Cheloii, Omid Ali Akbari and Davood Toghraie
This study aims to numerically investigate the heat transfer and laminar forced and two-phase flow of Water/Cu nanofluid in a rectangular microchannel with oblique ribs with angle…
Abstract
Purpose
This study aims to numerically investigate the heat transfer and laminar forced and two-phase flow of Water/Cu nanofluid in a rectangular microchannel with oblique ribs with angle of attacks equal to 0-45°. This simulation was conducted in the range of Reynolds numbers of 5-120 in volume fractions of 0, 2 and 4 per cent of solid nanoparticles in three-dimensional space.
Design/methodology/approach
This study investigates the effect of the changes of angle of attack of rectangular rib on heat transfer and hydrodynamics of two-phase flow. This study was done in three-dimensional space and simulation was done with finite volume method. SIMPLEC algorithm and second-order discretization of equations were used to increase the accuracy of results. The usage of nanofluid, application of rips with different angles of attacks and using the two-phase mixture method is the distinction of this paper compared with other studies.
Findings
The results of this research revealed that the changing angle of attack of ribs is an effective factor in heat transfer enhancement. On the other hand, the existence of rib on the internal surfaces of a microchannel increases friction coefficient. By increasing the volume fraction of nanoparticles, due to the augmentation of fluid density and viscosity, the pressure drop increases significantly. For all of the angle of attacks studied in this paper, the maximum rate of performance evaluation criterion has been obtained in Reynolds number of 30 and the minimum amount of performance evaluation criterion was been obtained in Reynolds numbers of 5 and 120.
Originality/value
Many studies have been done in the field of heat transfer in ribbed microchannel. In this paper, the laminar flow in the ribbed microchannel Water/Cu nanofluid in a rectangular microchannel by using two-phase mixture method is numerically investigated with different volume fractions (0-4 per cent), Reynolds numbers (5-120) and angle of attacks of rectangular rib in the indented microchannel (0-45°).
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Bijan Mohamadi, S. Ali Eftekhari and Davood Toghraie
The purpose of this paper is to investigate nonlinear vibrations of triple-walled carbon nanotubes buried within Pasternak foundation carrying viscous fluids.
Abstract
Purpose
The purpose of this paper is to investigate nonlinear vibrations of triple-walled carbon nanotubes buried within Pasternak foundation carrying viscous fluids.
Design/methodology/approach
Considering the geometry of nanotubes, the governing equations were initially derived using Timoshenko and modified couple stress theories and by taking into account Von-Karman expressions. Then, by determining boundary conditions, type of fluid motion, Knudsen number and, ultimately, fluid viscosity, the principal equation was solved using differential quadrature method, and linear and nonlinear nanotube frequencies were calculated.
Findings
The results indicated that natural frequency is decreased as the fluid velocity and aspect ratio increase. Moreover, as the aspect ratio is increased, the results converge for simple and fixed support boundary conditions, and the ratio of nonlinear to linear frequencies approaches. Natural frequency of vibrations and critical velocity increase as Pasternak coefficient and characteristic length increase. As indicated by the results, by assuming a non-uniform velocity for the fluid and a slip boundary condition at Kn = 0.05, reductions of 10.714 and 28.714% were observed in the critical velocity, respectively. Moreover, the ratio of nonlinear to linear base frequencies decreases as the Winkler and Pasternak coefficients, maximum deflection of the first wall and characteristic length are increased in couple stress theory.
Originality/value
This paper is a numerical investigation of nonlinear vibration analysis for triple-walled carbon nanotubes conveying viscous fluid.
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Vahid Jaferian, Davood Toghraie, Farzad Pourfattah, Omid Ali Akbari and Pouyan Talebizadehsardari
The purpose of this study is three-dimensional flow and heat transfer investigation of water/Al2O3 nanofluid inside a microchannel with different cross-sections in two-phase mode.
Abstract
Purpose
The purpose of this study is three-dimensional flow and heat transfer investigation of water/Al2O3 nanofluid inside a microchannel with different cross-sections in two-phase mode.
Design/methodology/approach
The effect of microchannel walls geometry (trapezoidal, sinusoidal and stepped microchannels) on flow characteristics and also changing circular cross section to trapezoidal cross section in laminar flow at Reynolds numbers of 50, 100, 300 and 600 were investigated. In this study, two-phase water/Al2O3 nanofluid is simulated by the mixture model, and the effect of volume fraction of nanoparticles on performance evaluation criterion (PEC) is studied. The accuracy of obtained results was compared with the experimental and numerical results of other similar papers.
Findings
Results show that in flow at lower Reynolds numbers, sinusoidal walls create a pressure drop in pure water flow which improves heat transfer to obtain PEC < 1. However, in sinusoidal and stepped microchannel with higher Reynolds numbers, PEC > 1. Results showed that the stepped microchannel had higher pressure drop, better thermal performance and higher PEC than other microchannels.
Originality/value
Review of previous studies showed that existing papers have not compared and investigated nanofluid in a two-phase mode in inhomogeneous circular, stepped and sinusoidal cross and trapezoidal cross-sections by considering the effect of changing channel shape, which is the aim of the present paper.
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