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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.

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.

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.

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.

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.

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.

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.

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°).

Thinking and deciding about the future of the city as a combination of complex and uncertain systems is extremely difficult. This complexity, uncertainty and difficulty will be increased when our thoughts and decisions address the city’s long-term future. Considering these issues, the need for future thinking and alternate thinking in the process of urban management and planning becomes even more necessary. The purpose of this paper is to identify and explain the alternate futures of Tehran.

For this purpose, this study have tried to study alternate future images of Tehran in an archetypal form of “growth, collapse, disciplined society and transformed society” using “Dator’s Four Generic Alternate Futures” method.

These alternate futures, after identifying their key trends and drivers, have been narrated in the form of four scenarios called: “capital business center,” “crossing the fate of ray,” “Tehran family” and “Tehran investigators.” Increasing the authority and responsibility of the local governance, modification of Tehran urban management model and development of voluntary cooperation and democratic participation, are among the policy recommendations made on the basis of these images.

Achieving these images in parallel with identifying the most important challenges and opportunities in alternate futures will provide the basis for policy-making in Tehran’s future urban governance. It can be a creative model for developing future images for other cities.

The purpose of this paper is to investigate the effects of news shocks on monetary policies using the dynamic stochastic general equilibrium (DSGE) model. To this end, two kinds of news shocks (known as technology and consumer preferences) are defined according to Khan and Tsoukalas’ (2012) approach.

In order to construct and simulate the DSGE model to approaching the real conditions in a case study, consumption habits in the utility function were concerned based on the assumption of the zero-value obtained from multiplying the inflation by the real interest rate in the Fisher’s equation, whereas the real interest rates in the long run were appointed as negative remark in simulating the monetary policy models. The estimation and simulation results for the research models indicated that monetary policies using the interest rate instrument identified the news shocks less frequently than monetary policies using the monetary base instrument.

The approximate value of the social loss function in the optimal commitment and discretionary monetary policies suggests that the optimal commitment policy is estimated to be lower in both cases. Due to value of the social loss function in optimal monetary policies with nominal interest rate instrument in the presence of news shocks, this could be claimed that monetary policy with interest rate instrument is more appropriate than the monetary policy with a monetary base instrument.

The approximate value of the social loss function in the optimal commitment and discretionary monetary policies suggests that the optimal commitment policy is estimated to be lower in both cases.

The purpose of this paper is to elucidate the performance discrepancies between shariah-compliant and non-shariah-compliant exchange-traded funds (ETFs), aiming to enrich the academic and practical understanding of Islamic finance‘s nuances in the ETF sector.

Initiating with a broad literature review to cement a theoretical backdrop on Islamic investment principles and the mechanics of shariah-compliant ETFs, the research progresses to devise a comparative analytical framework. This framework focuses on assessing ETF performance through metrics like net asset value returns and volatility, specifically analyzing Blackrock ETFs to draw distinctions in portfolio outcomes and asset compositions.

The examination highlights discernible variances in portfolio performance between shariah-compliant and their conventional counterparts, presenting instances where shariah-compliant ETFs, such as ISUS from Blackrock, deliver competitive returns despite their generally lower net assets compared to conventional ETFs like VUSA from Vanguard. Moreover, the ISUS ETF‘s holdings investigation revealed discrepancies with AAOIFI standards, questioning its strict Shariah compliance and adding depth to the analysis of Islamic financial instruments‘ integrity.

This paper significantly advances the scholarly dialogue on Islamic financial practices within the ETF landscape, providing empirical evidence of performance differentials and compliance intricacies. While prior research has touched upon Islamic investing, this study pioneers a detailed comparative scrutiny, equipped with a novel methodological approach, to dissect the shariah-compliant ETFs‘ operational and ethical frameworks, offering invaluable insights for investors, financial analysts and Islamic finance scholars.

This study aims to examine the potential of Sharia status as ex ante information to signal the quality of an issuing firm by improving the decision-making process of potential investors when assessing initial public offerings (IPOs) in an environment where information asymmetry is pronounced. Potential investors face challenges in evaluating and determining the true value of IPO issues, which inherently influences their decision-making. Consequently, this results in pronounced price fluctuations in IPO shares, leading to higher underpricing.

This study uses a sample of 350 IPOs listed on the Kuala Lumpur Stock Exchange (KLSE) between 2004 and 2021 to examine the signaling role of Sharia-compliance status. A three-model approach is used to ensure that the study's objectives are met. The first model investigates the effect of Sharia status on underpricing to determine whether the main beneficiary of such a signal is the investor or the issuer. The second model examines the effect of Sharia status on investor demand to determine if such a signal influences prospective investors' investment decision-making processes. The third model inspects the effect of Sharia status on investor divergence of beliefs to measure the signal's ability to reduce information asymmetry within the Malaysian IPO market.

The Malaysian IPO market relies heavily on the fixed-price mechanism, which exacerbates high information asymmetry, affecting potential investors' behavior, asset price formation and return generation on the first day of listing. The study results indicate that Sharia status does not have any signaling role in the Malaysian IPO market. This is because investors in the Malaysian market are driven by ex ante information that helps unveil relevant information that leads to capital gains. Furthermore, most new issues in the Malaysian IPO market fall under Sharia status, diluting the relevance of such information for prospective investors in determining profitable investments.

The findings highlight the challenges faced by issuing firms in estimating market demand due to limited premarket insights and the difficulties prospective investors face in identifying the quality of issuing firms. Efforts to provide more information on investor demand can reduce uncertainty and facilitate more informed decision-making.

This research stands as one of the pioneering efforts to provide an empirical explanation of the potential signaling influence of Sharia status in an emerging IPO market.

This paper aims to investigate whether all the dimensions of institutional pressures matter for energy management (EM) of manufacturing small and medium enterprises using evidence from Uganda.

This study used a cross-sectional design using evidence from 195 manufacturing small and medium enterprises in Uganda. The study was conducted by administering a questionnaire to obtain quantitative data which were analyzed using Smart Partial Least Square Structural Equation Modeling.

The findings revealed that two dimensions of institutional pressures (coercive and mimetic) positively and significantly predict EM, unlike normative pressures. Notable is that coercive pressures contribute more to EM than mimetic pressures.

This study uses a quantitative design; thus, future studies through interviews would offer more knowledge on EM. The government should reinforce regulations to achieve sustainable energy for all communities. Additionally, governments and industry associations should pay attention to the critical pressures (coercive and mimetic) to step up EM. Moreso, enterprise managers should comprehend government regulations and peers’ actions for effective EM.

This study contributes to EM literature by using institutional theory to examine the contribution of individual dimensions of institutional pressures to EM from the context.

There is no uniform methodology adopted worldwide for Shariah equity screening. The purpose of this research paper is to suggest reforms required to improve Shariah screening methodologies used for equities using Dow Jones Islamic Market Index, which is the world’s first such methodology adopted.

This research uses a qualitative research methodology that goes beyond analysing secondary data on the subject matter. It includes conducting semi-structured interviews with selected subject matter experts to gain insights into the practical issues associated with existing Shariah screening methodologies. The aim is to identify areas for potential reforms that can be implemented in the future. By combining secondary data analysis with first-hand perspectives from experts, this research provides a comprehensive understanding of the challenges and opportunities in Shariah screening, contributing to the development of practical and effective reforms.

The study recommends the inclusion of additional filters in Shariah screening methodologies to promote stocks that are not only Shariah-compliant but also socially responsible. It suggests that while a certain level of Shariah non-compliance threshold may be tolerated during the initial screening stage, over time, this accepted threshold should gradually decrease. The ultimate goal is to achieve 0% thresholds for Shariah-compliant equities. By advocating for stricter criteria and a progressive reduction in non-compliance tolerance, the study highlights the importance of continuously improving and refining Shariah screening practices to ensure higher levels of compliance and alignment with Shariah principles.

It is anticipated that the findings of this research provides original insights and contributions to existing knowledge. It offers novel perspectives, innovative approaches and solutions to address specific areas in need of reform. By focusing on enhancing the effectiveness and standardisation of Shariah-compliant investment practices, the research brings fresh perspectives and adds value to the field. Its unique contribution lies in identifying and addressing emerging challenges and proposing improvements in Shariah screening methodologies.

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.

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.

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.

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.

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.

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.