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The fully developed laminar mixed convection flow in inclined tubes subject to axially and circumferentially uniform heat flux has been studied numerically for a Boussinesq fluid. Dual solutions characterized by a two‐ and a four‐vortex secondary flow structure in a cross‐section normal to the tube’s longitudinal axis have been found for different combinations of the Grashof number Gr and of the tube inclination α for all Prandtl numbers between 0.7 and 7. In the two‐parameter space defined by Gr and α dual solutions occur: at a given α, if the Grashof number exceeds a critical value Gr_ℓ (for horizontal tubes Gr_ℓ is approximately 5.5 × 10⁵, 1.7 × 10⁵ and 1.7 × 10⁴ respectively for Pr = 0.7, 7 and 70); at a given Gr, if the tube inclination is below a critical value α_c (for Gr = 10⁶ this critical angle is approximately 62.5° and 83.5° respectively for Pr = 0.7 and 7). Numerical experiments carried out for developing flows indicate that the two‐vortex solution is the only stable flow structure.

The effects of tube inclination and Grashof number on the fully developed hydrodynamic and thermal fields are investigated numerically for laminar ascending flow of air and water in uniformly heated circular tubes. The effects of the buoyancy induced secondary flow on the hydrodynamic and thermal fields are complex and strongly dependent on the Grashof number, the Prandtl number and the tube inclination. The influence of these parameters on the intensity of the secondary flow, on the distortion of the axial velocity profile and of the temperature field from the corresponding distributions for pure forced flow, as well as on the circumferential variation of the local shear stress and of the local Nusselt number are analysed. The average shear stress is higher than for pure forced flow and it increases with both the tube inclination and with the Grashof number. The average Nusselt number is higher than for pure forced flow and increases with the Grashof number. For a given fluid and Grashof number there exists an optimum tube inclination which maximizes the average Nusselt number. Correlations for the average Nusselt number in terms of Gr and Pr are presented for four different tube inclinations.

The aim is to study the conjugate problem of developing laminar mixed convection flow and heat transfer of water‐Al₂O₃ nanofluid inside an inclined tube submitted to a uniform wall heat flux.

The set of non‐linear, coupled and fully elliptic governing equations has been solved using a “finite‐control‐volume” numerical method, the classical power‐law scheme for computing heat and momentum fluxes staggered and non uniform grids for spatial discretization of various regions of the tube.

Numerical results have shown that the presence of nanoparticles slightly intensifies the secondary flow due to buoyancy, in particular in the developing region. It also increases the average Nusselt number and decreases slightly the product ReC_f with respect to those of water. For the horizontal inclination, two new correlations have been proposed to calculate these two variables in the fully developed region, for Grashof number ranging from 10³ to 10⁵ and particle volume concentrations up to 7 per cent.

The results of this study can be employed for various practical heat transfer and thermal applications using nanofluids.

The present study constitutes an original contribution to the knowledge of nanofluid thermal behaviour.

The purpose of this paper is to examine the relationship between operational risk management and customer complaints. It also determines whether product complexity moderates the relationship between the operational risk management and customer complaints.

This study utilizes a quantitative method: quantitative data were collected using a questionnaire. The population of this study is 1,845 local conventional bank branches based in Malaysia.

The findings revealed that components of operational risk management, namely practice of hazard identification and formulation of implementation of risk control, have negative and significant relationships with customer complaints. Empirical evidence confirmed the moderating effects of product complexity on the relationship between operational risk management and customer complaints.

From the perspective of developing countries, the main contribution of this study is the elucidation of the effect of operational risk management on customer complaints in commercial banks in Malaysia. This study confirmed the usability of the resource-based view theory in the banking industry, as well as operational risk management as a bank resource.

To determine the axial evolution of the hydrodynamic and the thermal fields for mixed convection in inclined tubes and to investigate the presence of flow reversal.

The elliptical, coupled, steady state, three‐dimensional governing partial differential equations for heated ascending laminar mixed convection in an inclined isothermal tube were solved numerically using a finite volume staggered grid approach.

The axial evolution of the velocity profiles and fluid temperatures show that upstream diffusion has an important effect near the inlet of the heating region. As a result, both the wall shear stress and the Nusselt number are affected upstream of the heating zone. Flow reversal occurs of GF≥9 × 10⁵. The shape and size of the region with negative velocities depends strongly on the value of the Grashof number. The effect of the Grashof number on the axial evolution of the wall shear stress and the Nusselt number is shown to be very important in the region of developing flow.

The results have been calculated for one Reynolds number (Re=100), a single fluid (air) and one tube inclination (45°).

Further results of this type can be mapped and would be useful for heat exchanger design.

This is the first time that flow reversal has been calculated numerically for inclined tubes. Most previous studies concern horizontal or vertical tubes and use axially parabolic equations which are easier to solve but can not calculate the flow field in the region with backflow.

The purpose of this paper is to present methods for assessing and mapping the complexity of products and their assembly. In cases of complexity of assembly it is important to consider and model at the product design stages when only data about individual parts/products and their assembly attributes are known. Assessing the complexity of assembly systems, based on the attributes of their components, is an essential step towards designing them for the least complexity.

This paper presents a mapping method between the complexity of products and their variants and complexity of the system needed to assemble them. A method has also been developed to assess and compare the complexity of assembly systems based on the characteristics of their physical components for comparison and re‐design to reduce complexity.

The complexity dependency matrix estimates the average assembly equipment complexity for a certain product based on the interactions between parts handling, insertion and assembly attributes and assembly system functions. An automobile engine piston, domestic appliance drive, car fan motor and a three‐pin electric power plug products were used to demonstrate the application of the developed methodology.

The developed methods can be used by products and assembly systems designers to identify and alleviate major sources of complexity.

The purpose of this paper is to study the influence of magnetic field on entropy generation and natural convection inside an enclosure filled with a hybrid nanofluid and having a conducting wavy solid block. Also, the effect of fluid–solid thermal conductivity ratio is investigated.

The governing equations that are formulated in the dimensionless form are discretized via finite volume method. The velocity–pressure coupling is assured by the SIMPLE algorithm. Heat transfer balance is used to verify the convergence. The validation of the numerical results was performed by comparing qualitatively and quantitatively the results with previously published investigations.

The results indicate that the magnetic field and the conductivity ratio of the wavy solid block can significantly affect the dynamic and thermal field and, consequently, the heat transfer rate and entropy generation because of heat transfer, fluid friction and magnetic force.

To the best of the authors’ knowledge, the present numerical study is the first attempt to use hybrid nanofluid for studying the entropy generation because of magnetohydrodynamic natural convective flow in a square cavity with the presence of a wavy circular conductive cylinder. Irreversibilities due to magnetic effect are taken into account. The effect of fluid–solid thermal conductivity ratio is considered.

Upward mixed convection flow of air in a uniformly heated vertical tube was studied numerically using the three‐dimensional elliptic conservation equations and the Launder and Sharma low Reynolds number k–ε turbulence model. For Re=1,000 the fully developed flow field undergoes two transitions as the Grashof number increases: thus, this flow field is laminar for Gr<8×10⁶, turbulent for 8×10⁶<Gr<5×10⁷ and again laminar for Gr>5×10⁷. In the entry region, turbulent kinetic energy decays monotonically for Gr≤3×10⁶ and Gr≥7.1×10⁷. For Gr between these two values it initially increases from the imposed inlet condition and then decreases towards its calculated fully developed value. The mean velocity profiles as well as the axial evolution of the skin friction coefficient are presented for representative values of Gr.

The aim of this article is to present the results of a parametric analysis of the entropy generation due to mixed convection in the entry‐developing region between two differentially heated isothermal vertical plates.

The entropy generation was estimated via a numerical solution of the mass, momentum and energy conservation equations governing the flow and heat transfer in the vertical channel between the two parallel plates. The resultant temperature and velocity profiles were used to estimate the entropy generation and other heat transfer parameters over a wide range of the operating parameters. The investigated parameters include the buoyancy parameter (Gr/Re), Eckert number (Ec), Reynolds number (Re), Prandtl number (Pr) and the ratio of the dimensionless temperature of the two plates (θ_T).

The optimum values of the buoyancy parameter (Gr/Re) optimum at which the entropy generation assumes its minimum for the problem under consideration have been obtained numerically and presented over a wide range of the other operating parameters. The effect of the other operating parameters on the entropy generation is presented and discussed as well.

The results of this investigation are limited to the geometry of vertical channel parallel plates under isothermal boundary conditions. However, the concept of minimization of entropy generation via controlling the buoyancy parameter is applicable for any other geometry under any other thermal boundary conditions.

The results presented in this paper can be used for optimum designs of heat transfer equipment based on the principle of entropy generation minimization with particular focus on the optimum design of plate and frame heat exchanger and the optimization of electronic packages and stacked packaging of laminar‐convection‐cooled printed circuits.

This paper introduces the entropy generation minimization via controlling the operating parameters and clearly identifies the optimum buoyancy parameter (Gr/Re) at which entropy generation assumes its minimum under different operating conditions.

This study aims to investigate the relationship between building smart factories in manufacturing small- and medium-sized enterprises (SMEs) and firm performance and the moderating effect according to product complexity and company size.

Data were collected from 206 companies selected in the list of SMEs, which had built smart factories, provided by the Smart Manufacturing Innovation Center in Korea. The collected data were analyzed using structural equation modeling (SEM) technique.

First, production automation and big data utilization are associated positively with productivity, but not significantly with export performance. Second, supply chain integration is associated positively with both productivity and export performance. Third, product complexity moderates negatively the relationship of productivity with each of production automation, big data utilization and supply chain integration while moderating positively the relationship between supply chain integration and export performance. Finally, company size does not moderate significantly the relationship between productivity or export performance with any of production automation, big data utilization and supply chain integration.

This study contributes theoretically to literature by demonstrating the usefulness of building smart factories and suggesting how SMEs build a smart factory to enhance productivity and export performance from a business perspective. Moreover, this study contributes practically by proposing that SMEs should put priority on supply chain integration over production automation and big data utilization and execute different strategies of building smart factories depending on product complexity.