Search results

The purpose of this paper is to study the effects of finite wall thickness on the natural convection and entropy generation in a square cavity filled with Al₂O₃–water nanofluid in the presence of bottom heat source.

The moving isothermal heater was placed on the bottom solid wall. The vertical walls (left and right walls) were fully maintained at low temperatures. The rest of the bottom solid wall along with the top horizontal wall was kept adiabatic. The boundaries of the domain are assumed to be impermeable; the fluid within the cavity is a water-based nanofluid having Al₂O₃ nanoparticles. The Boussinesq approximation is applicable. The dimensionless governing equations subject to the selected boundary conditions are solved using the finite difference method. The current proposed numerical method is proven excellent through comparisons with the existing experimental and numerical published studies.

Numerical results were demonstrated graphically in several forms including streamlines, isotherms and local entropy generation, as well as the local and average Nusselt numbers. The results reveal that the thermal conductivity and thickness of the solid wall are important control parameters for optimization of heat transfer and Bejan number within the partially heated square cavity.

According to the past research studies mentioned above and to the best of the authors’ knowledge, the gap regarding the problem with entropy generation analysis and natural convection in partially heated square cavity has yet to be filled. Because of this, this study aims to investigate the entropy generation analysis as well as the natural convection in nanofluid-filled square cavity which was heated partially. A square cavity with an isothermal heater located on the bottom solid horizontal wall of the cavity and partly cold sidewalls are essential problems in thermal processing applications. Hence, the authors believe that this present work will be a valuable contribution in improving the thermal performance.

This paper aims to study analytically and numerically the problem of transient natural convection heat transfer in a trapezoidal cavity with spatial side-wall temperature variation.

The governing equations subject to the initial and boundary conditions are solved numerically by the finite difference scheme consisting of the alternating direction implicit method and the tri-diagonal matrix algorithm. The left sloping wall of the cavity is heated to non-uniform temperature, and the right sloping wall is maintained at a constant cold temperature, while the horizontal walls are kept adiabatic.

It is shown that the heat transfer rate increases in non-uniform heating increments, whereby low wave number values are more affected by the convection. The best heat transfer enhancement results from larger side wall inclination angle; however, trapezoidal cavities require longer time compared to that of square to reach steady state.

The study of natural convection heat transfer in a trapezoidal cavity filled with nanofluid and heated by spatial side-wall temperature has not yet been undertaken. Thus, the authors of the present study believe that this work is valuable.

The aim of this study is to investigate the effects of two-phase nanofluid model on mixed convection in a double lid-driven square cavity in the presence of a magnetic field. The authors believe that this work is a good contribution for improving the thermal performance and the heat transfer enhancement in some engineering instruments.

The current work investigates the problem of mixed convection heat transfer in a double lid-driven square cavity in the presence of magnetic field. The used cavity is filled with water-Al₂O₃ nanofluid based on Buongiorno’s two-phase model. The bottom horizontal wall is maintained at a constant high temperature and moves to the left/right, while the top horizontal wall is maintained at a constant low temperature and moves to the right/left. The left and right vertical walls are thermally insulated. The dimensionless governing equations are solved numerically using the Galerkin weighted residual finite element method.

The obtained results show that the heat transfer rate enhances with an increment of Reynolds number or a reduction of Hartmann number. In addition, effects of thermophoresis and Brownian motion play a significant role in the growth of convection heat transfer.

According to above-mentioned studies and to the authors’ best knowledge, there has no study reported the MHD mixed convection heat transfer in a double lid-driven cavity using the two-phase nanofluid model. Thus, the authors of the present study believe that this work is valuable. Therefore, the aim of this comprehensive numerical study is to investigate the effects of two-phase nanofluid model on mixed convection in a double lid-driven square cavity in the presence of a magnetic field. The authors believe that this work is a good contribution for improving the thermal performance and the heat transfer enhancement in some engineering instruments.

This paper aims to investigate the fluid structure interaction analysis of conjugate natural convection in a square containing internal solid cylinder and flexible right wall.

The right wall of the cavity is flexible, which can be deformed due to the interaction with the natural convection flow in the cavity. The top and bottom walls of the cavity are insulated while the right wall is cold and the left wall is partially heated. The governing equations for heat, flow and elastic wall, as well as the grid deformation are written in Arbitrary Lagrangian–Eulerian formulation. The governing equations along with their boundary conditions are solved using the finite element method.

The results of the present study show that the presence of the solid cylinder strongly affects the transient solution at the initial times. The natural convection flow changes the shape of the flexible right wall of the cavity into S shape wall due to the interaction of the flow and the structure. It is found that the increase of the flexibility of the right wall increases the average Nusselt number of the hot wall up to 2 per cent.

To the best of the authors' knowledge, the unsteady natural convection in an enclosure having a flexible wall and inner solid cylinder has never been reported before.

The purpose of this paper is to study problem of conjugate MHD natural convection of Al₂O₃-water nanofluid in a square cavity with conductive inner block using Buongiorno’s two-phase model numerically.

An isothermal heater is placed on the left wall of the square cavity, while the right wall is maintained at a constant cold temperature. The horizontal top and bottom walls are kept adiabatic. The boundaries of the annulus are assumed to be impermeable, the fluid within the cavity is a water-based nanofluid having Al₂O₃ nanoparticles. The Boussinesq approximation is applicable. The governing equations subject to the boundary conditions are solved using the finite difference method.

Numerical results are presented graphically in the form of streamlines, isotherms and nanoparticles distributions as well as the local and average Nusselt numbers. The results show that the effect of the nanoparticles addition on the average Nusselt number is essential for low Rayleigh, high Hartmann and high values of length ratio when attenuated the convective flow.

According to exist studies and to the authors’ best knowledge, so far, there have been no studies of conjugate natural convection of Al₂O₃-water nanofluid in a square cavity with a conductive inner block using Buongiorno’s two-phase model with the effect of the magnetic field. Thus, the authors believe that this work is new and valuable. The aim of this study is to investigate the MHD natural convection of Al₂O₃-water nanofluid in a square cavity with conductive inner block using Buongiorno’s two-phase model.

This chapter explores the role and impact of adaptive thinking and transformational leadership in developing and leading an enabling culture that aligns with a school’s vision and mission. This chapter will also probe the varying dimensions that enable or inhibit a school culture and the tools needed to shape and maintain it including the challenges posed in the Middle East and North Africa (MENA) region. In this chapter, examples of adaptive challenges, data-driven instructions, and effective use of technology, will be referred to as one dimension of a culture that shows alignment or lack of it with the school’s vision and mission, the role and impact of transformative adaptive leadership on school’s overall culture, especially in the UAE, and MENA region. Finally, this chapter will examine the impact of adaptive and distributed leadership in leading a cultural change.

The purpose of this paper is to present possible strategic actions that aim to recover the value still remaining in industrial waste.

The research method is a multiple case study. The sample included six Brazilian companies of the footwear, metal-mechanics, pulp and paper, beverages, chemical and food industries. The study investigated the production process, waste generation, internal reuse, the destination of unused waste, difficulties and strategic challenges.

Possible strategies to recover the value remaining in industrial waste are increasing the internal reuse, developing new routes to other industries, reducing the waste generation, increasing the destination to cooperatives or recycling companies, which require studies to understand the legislation and agility in licensing and reducing the logistical cost of the destination.

The study relies on six case studies. Further research shall encompass an entire industry, starting with hypotheses derived from the cases.

The main barriers observed for reuse and recycling are uncertainties and ambiguities in the interpretation of legislation, the difficulty for the environmental licensing for recycling operations, excessive logistics costs for exploration opportunities and the lack of research to reduce the waste generation and to increase the internal reuse.

Waste managed by scavengers’ cooperatives can offer jobs to the people of vulnerable communities.

The study offers robust hypotheses to be tested in a survey on the capacity of a waste management strategy to create competitive advantage in the industry. The study establishes a relationship between waste management and three competitive enablers, compliance, corporate image and green market.

The purpose of this study is to describe cosmetics purchase behavior of young, educated Muslim females in Malaysia and to explore its relationship with certain potential antecedents.

This study uses a survey on a sample of female consumers from four higher education institutions in the urban area of Bangi Selangor, Malaysia. From their respective institutions, 150 respondents were selected through the purposive sampling method. Self-administered questionnaire has been used to gather information from the respondents. The survey data were analyzed using descriptive, t-test and correlation analyses to accomplish the study objectives.

The study indicates that millennial Muslim cosmetic purchase behavior falls under the “Limited Decision Making” classification. The classification is due to the pattern of pro-active behaviors exhibit through the information search for details about ingredients, halal clue, countries of origin, health safety guarantee and the benefits of the cosmetic products. Young, educated female consumers adore branded cosmetic items and show willingness to accept higher prices for the branded items. Despite brand consciousness, they demonstrate a relatively high concern on the halalness of the product. Based on the correlation analysis, all variables were found to be significant and the most significant of them was brand.

Millennial consumers are information technology savvy and have access to vast information about products. As a result, the findings reiterate that millennial consumers demonstrate different purchase behavior, which is worth exploring by future researchers. In addition, other latent antecedents such as religiosity and world view are worth including in future studies.

Cosmetic manufacturers and marketers must ensure that their products signal positive images to fit the expectations of young and educated Muslim consumers. Although brand conscious, such consumers demonstrate prudent behavior in terms of searching for halalan and toyyiban products.

This study adds value in the area of halal product marketing because of two unique focuses. First, it examines the purchase of cosmetic products, which are relatively understudied compared to halal food. Second, it considers the perspectives of educated Muslim millennials, who are expected to demonstrate more specific purchase behaviors than a generalized millennial group. Therefore, the originality of this study revolves around the consideration of these two aspects, which are relevant to contemporary business marketing discussions.