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Because the local Re numbers, ratio of inertia to viscous forces, are not same at different regions of the enclosures, the present study aims to deal with the influences of using the turbulent/transition models on numerical results of the natural convection and flow field within a trapezoidal enclosure.

The three-dimensional (3D) trapezoidal enclosure with different inclined side walls of 75, 90 and 105 degrees are considered, where the side walls are heated and cooled at Ra = 1.5 × 10⁹ for all cases. The turbulent models of the k-ε-RNG, k- ω-shear-stress transport (SST) and the newly developed transition/turbulent model of Re_θ-γ-transition SST are utilized to analyze the fluid flow and heat transfer characteristics within the enclosure and compared their results with validated results.

Comprehensive comparisons have been carried out for all cases in terms of flow and temperature fields, as well as turbulent quantities, such as turbulent kinetic energy and turbulent viscosity ratio. Furthermore, the velocity and thermal boundary layers have been investigated, and the approximate transition regions for laminar, transitional and turbulent regimes have been determined. Finally, the heat transfer coefficient and skin friction coefficient values have been presented and compared in terms of different turbulent models and configurations. The results show that the transition/turbulence model has better prediction for the flow and heat fields than fully turbulent models, especially for local parameters for all abovementioned governing parameters.

The originality of this work is to analyze the 3D turbulent/transitional natural convection with different turbulence/transition models in a trapezoidal enclosure.

The purpose of this paper is to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with two immiscible fluids of nanofluid and air.

One surface of the enclosure is jagged and another one is smooth. The finite volume approach is applied for computation. There are two partially side heaters. Furthermore, the Navier–Stokes equations and entropy generation formulation are solved in the 3D form.

The effects of different governing parameters, such as the jagged surface (JR=0, 0.02, 0.04, 0.08, 0.12 and 0.16), Rayleigh number (10³⩽Ra⩽10⁶) and solid volume fraction of nanofluid (φ=1, 1.5, 2 vol%), on the fluid flow, temperature field, Nusselt number, volumetric entropy generation and Bejan number are presented, comprehensively. The results indicate that the average Nusselt number increases with the increase in the Rayleigh number and solid volume fraction of nanofluid. Moreover, the flow structure is significantly affected by the jagged surface.

The originality of this work is to analyze the natural-convection fluid flow and heat transfer under the influence of jagged surfaces of electrodes in high-current lead–acid batteries.

The nanofluid flow and heat transfer within a heat exchanger, with different thermal arrangements of internal active bodies, are investigated.

For the numerical simulations, the lattice Boltzmann method is utilized. The KKL model is used to predict the dynamic viscosity of CuO-water nanofluid. Furthermore, the Brownian method is taken account using this model. The influence of shapes of nanoparticles on the heat transfer performance is considered.

The results show that the platelet nanoparticles render higher average Nusselt number showing better heat transfer performance. In order to perform comprehensive analysis, the heatline visualization, local and total entropy generation, local and average Nusselt variation are employed.

The originality of this work is carrying out a comprehensive investigation of nanofluid flow and heat transfer during natural convection using lattice Boltzmann method and employing second law analysis and heatline visualization.

This study is aimed at scrutinizing the moderating influence of disruption orientation (DO) on the nexus between government support (GS) and the multidimensional performance of small and medium-sized enterprises (SMEs) through the COVID-19 turbulence.

A cross-sectional survey design was engaged for data collection using structured hand-delivered questionnaires. Partial least square structural equation modeling was used to test the hypothesized relationships based on a sample response of 170 SMEs from Kano, Nigeria.

GS has no direct impact on both financial performance (FP) and non-financial performance (NFP) of SMEs in Nigeria during the COVID-19 crisis. However, DO demonstrates a constructive direct significant influence on the SMEs’ FP and NFP. Additionally, DO positively moderates the relationship between GS and the FP and NFP.

The findings implied that GS could not solitarily make an impact on SMEs’ FP and NFP during crises. Nevertheless, DO is imperative in revitalizing the impact of GS on both performance dimensions of SMEs during disruptions. Consequently, policymakers should consider DO as a precondition for SMEs access to GS, if SMEs performance is the target for improvement.

The research model is the first to integrate and empirically validate the moderating effect of DO on the GS and SME performance relationships during crises. The study particularly highlights the role of DO in SMEs during crises and the limited role of GS. This study, therefore, contributes theoretically to the disruption management and GS literature for SMEs.

Building on network theory, this study aims to examine how network resources and network knowledge utilization influence mobility within networks of knowledge workers. Specifically, it examines how the availability of resources in a network and knowledge utilization, in a period impacts the structure of the focal network in the following period.

The study uses data from the National Basketball Association to depict the mobility of knowledge workers in a network. Because of the nature of the dependent variable, the study used a conditional fixed-effects quasi-maximum-likelihood Poisson regression as an analytical methodology.

The study finds that network resources are partially significant in predicting knowledge workers’ mobility and that knowledge utilization of networks of knowledge workers in one period negatively affects networks’ structure in the following period.

The study advances our understanding of the knowledge workers’ mobility phenomenon by examining network-level factors that influence the mobility of knowledge workers. It addresses the issue from a different theoretical perspective that is rarely used in studies of knowledge workers, which mostly draw from the traditional human resource literature. Additionally, it contributes to the emerging literature of network dynamics by studying factors that affect network changes. The study also responds to the calls that advocate using sports data to examine organizational phenomena.

This paper aims to examine the synchronous and lagged relationships between CEOs' pay and the performance of a group of public companies that had won a very prestigious award: the Malcolm Baldrige National Quality Award (MBNQA).

This study uses three rates of return to represent firm performance: return on assets, return on equity and holding period return. Regression analysis is used to determine the direction of causality between CEO pay and firm performance and the existence of lagged relationship between them.

The findings indicate the existence of synchronous and lagged relationships between CEO pay and firm performance. However, the direction of causality is mainly from pay to performance, and not vice versa.

The results presented in this paper are limited by the small sample size of MBNQA winning companies. Although the award began in 1988, only a few companies won the award each year and many of them were not public companies. In addition, five companies won the award twice and one company won the award three times, which further reduces the sample size.

This paper finds the existence of synchronous and lagged relationships between CEO pay and firm performance for a group of quality companies.

Examines the construction of the funding formula, following the 1988 Education Act, used to determine the levels of devolved budgets in three English local education authorities (LEAs). Explains that, in each LEA, a team was formed to determine the funding formula. Also explains that, as most schools pre‐local management of schools (LMS) only kept aggregate records showing the cost of education at the levels of primary/secondary sectors rather than individual school level, the LMS teams faced serious problems in defining budget parameters, identifying cost elements and attributing costs to functions. More critically, points out that while the 1988 Education Act made it clear that the new budgeting system should be comprehensive in the sense of not merely reflecting past expenditure patterns but being based on perceived education needs, the LMS teams developed funding formulae which predominantly preserved the status quo established by historical expenditure patterns. Explores both the arguments and the mechanisms which each LMS team deployed in order to produce an incrementalist budgeting system and the constraints that operated on incrementalism.

This case study is most suitable for a target audience of graduate-level students in leadership and/or change management classes. It will help students to apply a change management model to an existing problem/change and analyze its applicability, recognize different leadership approaches in practice and assess their appropriateness in different contexts and present key findings and ideas in front of an audience.

This case study examines the leadership of Dr. Mahmoud Khattab, CEO of B.TECH, during the turbulent times of the 2011 Egyptian Revolution. B.TECH was founded in 1997 as a subsidiary of the Egyptian home appliances manufacturer Olympic Electric, to enter the retail market. The morning after January 28, 2011, the “Friday of Rage,” Khattab found the company’s stores looted and seized, and the employees panicked. The company leader was pressured to decide the next steps quickly. Everything was condensed into a dilemma of whether to keep the stores open but potentially risk employee trust and safety as well as the company’s assets – or close them but lose revenue, the ability to pay workers and the company’s market leader position. Students should also identify and reflect on the elements of leadership that contributed to a business success in a turbulent political environment. This case study highlights critical leadership and management decisions during an unexpected crisis that threatened the company’s operations and diversification efforts. Khattab acted almost instinctively, using the interpersonal and creative skills he had acquired while running a family business in his native Egypt and while occupying various leadership roles.

This case study is particularly suitable for classes on change management and leadership for university students at the graduate level.

Teaching notes are available for educators only.

CSS11: Strategy.