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This paper aims to conduct numerical simulations to investigate steady-state laminar Rayleigh–Bénard convection of yield stress fluids obeying Bingham model in rectangular cross-sectional cylindrical annular enclosures. In this investigation, axisymmetric simulations have been carried out for nominal Rayleigh number range Ra = 10³ to 10⁵, aspect ratio range AR = 0.25 to 4 (i.e. AR = H/L where H is the enclosure height and L is the difference between outer and inner radii) and normalised inner radius range r_i/L = 0 to 16 (where r_i is internal cylinder radius) for a nominal representative Prandtl number Pr = 500. Both constant wall temperature (CWT) and constant wall heat flux (CWHF) boundary conditions have been considered for differentially heated horizontal walls to analyse the effects of wall boundary condition.

The bi-viscosity Bingham model is used to mimic Bingham fluids for Rayleigh–Bénard convection of Bingham fluids in vertical cylindrical annuli. The conservation equations of mass, momentum and energy have been solved in a coupled manner using the finite volume method where a second-order central differencing scheme is used for the diffusive terms and a second-order up-wind scheme is used for the convective terms. The well-known semi-implicit method for pressure-linked equations algorithm is used for the coupling of the pressure and velocity.

It is found that the convective transport strengthens (weakens) with an increase in Ra (AR) for both Newtonian (i.e. Bn = 0) and Bingham fluids, regardless of the boundary conditions. Moreover, the strength of convection is stronger in the CWT configuration than that is for CWHF boundary condition due to higher temperature difference between horizontal walls for both Newtonian (i.e. Bn = 0) and Bingham fluids. The mean Nusselt number Nūcy does not show a monotonic increase with increasing Ra for AR = 1 and r_i/L = 4 because of the change in flow pattern (i.e. number of convection rolls/cells) in the CWT boundary condition, whereas a monotonic increase of Nūcy with increasing Ra is obtained for the CWHF configuration. In addition, Nūcy increases with increasing r_i/L and asymptotically approaches the corresponding value obtained for rectangular enclosures (r_i/L → ∞) for both CWT and CWHF boundary conditions for large values of r_i/L. It is also found that both the flow pattern and the mean Nusselt number Nūcy are dependent on the initial conditions for Bingham fluid cases, as hysteresis is evident for AR = 1 for both CWT and CWHF boundary conditions.

Finally, the numerical findings have been used to propose a correlation for Nūcy in the range of 0.25 ≤ r_i/L ≤ 16, 0.25 ≤ AR ≤ 2 and 5 × 10⁴ ≤ Ra ≤ 10⁵ for the CWHF configuration.

Among the several sub‐themes for this Special Issue this paper aims to deal, broadly, with the Hindu view of economics and allied matters.

The approach is a conceptual one that highlights a few crucial aspects of the “positive” flank of Hinduism vis‐à‐vis its “normative” dimension. Researchers, thinkers, scholars and, above all, some important but ignored realizers of Hindu psycho‐philosophy, have been dug into for materials comprising the paper.

The findings clearly show that the amazing sustainability of Bharat's (i.e. India's) socio‐economic processes, structures and systems, despite the tortures of history visiting her, can be explained by her abiding fidelity to the eternal as the basis of the temporal. This is the very foundation of the sacro‐secular character of Hindu culture.

The expected impact is long‐term through deep‐structure germination on a wide tract. Hurried practical application in tiny fractions is not intended as this will be premature and superficial.

The contents of this paper are meant to generate a holistic and respectful orientation to the forging of constructive links between culture and economics in the context of Hinduism.

The purpose of this study is to perform a detailed review on the numerical modeling of multiphase and multicomponent flows in microfluidic system using phase-field method. The phase-field method is of emerging importance in numerical computation of transport phenomena involving multiple phases and/or components. This method is not only used to model interfacial phenomena typical to multiphase flows encountered in engineering and nature but also turns out to be a promising tool in modeling the dynamics of complex fluid-fluid interfaces encountered in physiological systems such as dynamics of vesicles and red blood cells). Intrinsically, a priori unknown topological evolution of interfaces offers to be the most concerning challenge toward accurate modeling of moving boundary problems. However, the numerical difficulties can be tackled simultaneously with numerical convenience and thermodynamic rigor in the paradigm of the phase field method.

The phase-field method replaces the macroscopically sharp interfaces separating the fluids by a diffuse transition layer where the interfacial forces are smoothly distributed. As against the moving mesh methods (Lagrangian) for the explicit tracking of interfaces, the phase-field method implicitly captures the same through the evolution of a phase-field function (Eulerian). In contrast to the deployment of an artificially smoothing function for the interface as used in the volume of a fluid or level set method, however, the phase-field method uses mixing free energy for describing the interface. This needs the consideration of an additional equation for an order parameter. The dynamic evolution of the system (equation for order parameter) can be described by Allen–Cahn or Cahn–Hilliard formulation, which couples with the Navier–Stokes equation with the aid of a forcing function that depends on the chemical potential and the gradient of the order parameter.

In this review, first, the authors discuss the broad motivation and the fundamental theoretical foundation associated with phase-field modeling from the perspective of computational microfluidics. They subsequently pinpoint the outstanding numerical challenges, including estimations of the model-free parameters. They outline some numerical examples, including electrohydrodynamic flows, to demonstrate the efficacy of the method. Finally, they pinpoint various emerging issues and futuristic perspectives connecting the phase-field method and computational microfluidics.

This paper gives unique perspectives to future directions of research on this topic.

This paper presents both conceptual insights and practical examples about spiritually transformed leadership. The Yoga‐Vedanta spiritual model is its anchor. Some profound Western thinkers, besides Indian realizers, have provided clues relevant to this approach. This paper explores a much wider vista for transformational leadership beyond business success or political strategy. Transformed leaders are the cause, transformation of followers the effect.

In this study, workplace spirituality is discussed in the context of remote work and the COVID-19 pandemic. First, the focus is on the changes in the meaning and function of employees in the organization during the evolutionary process of industrialization and management paradigms. Afterward, conceptual frameworks for spirituality and workplace spirituality are presented, and in the last section, academic studies that deal with workplace spirituality with distance or hybrid work arrangements are included. Early studies offer insights and recommendations on conceptualizing, developing, and managing workplace spirituality. They all emphasize that spirituality is necessary for remote work as a tool to overcome stress and mental health problems and increase employee well-being. Unfortunately, the remote work and workplace spirituality literature is relatively narrow and needs to be expanded.

From the solution of full Navier—Stokes and energy equations, the development of the flow field and heat transfer characteristics in a radial jet reattachment flow have been analysed. The influence of Reynolds number of re‐attachment length for the case of steady laminar flows has been determined. However, beyond a Reynolds number of 250, the flow field becomes unsteady and has been found to have a periodic nature. This periodic flow has been found to persist up to a Reynolds number of 750. The periodicity has been characterized by the Strouhal number which shows a slight but continuous variation with Reynolds number around a value of 0.12. The point of maximum heat transfer is within the re‐attachment zone in the range of Reynolds numbers studied.

The study aims to propose a conceptual Bhartiya (Indian) model of workplace spirituality (WPS) in non-profit organisations (NPOs) in the context of burnout and resilience by synthesising the concepts of the east and the west. The researchers have kept an open approach by exploring various dimensions of WPS by reviewing the extant literature of both the east and the west. The researchers delved into Bhartiya (Indian) scriptures to identify the concepts that have similarity with the dimensions of WPS so that it may further assist in facilitating those dimensions in NPOs. Furthermore, to propose a conceptual Bhartiya model for NPOs, the researchers synthesised the literature pool of Bhartiya studies on WPS. They examined how WPS decreases burnout and leads to resilience. The study’s findings reveal that concepts from Bhartiya scriptures such as Karm Yog (Nishkam Karm, self-abnegation, swadharm), parasparam bhavayantaha, loksangrah, daivi sampat and kritagyata are instrumental in facilitating the constructs of WPS. Meaningful work is facilitated through karm yog; sense of community is facilitated through parasparam bhavayantaha and loksangrah; and alignment with organisational values is facilitated through daivi sampat and kritagyata. The findings further suggest that WPS is an antidote to burnout and an enabler of resilience.

Due to several unique characteristics, such as high tensile strength, low extensibility, high frictional resistance, biodegradability, eco-friendliness and cheapness, Jute ranks second just after cotton with respect to its worldwide consumption and production. To overcome the difficulties of the existing Jute grading procedure, this paper aims to focus on the application of decision-making trial and evaluation laboratory (DEMATEL) and multi-attributive border approximation area comparison (MABAC) methods for evaluation of 10 Tossa Jute fiber lots based on strength, defects, root content, color, fineness and bulk density properties.

The DEMATEL method divides all the six physical properties of Jute fiber into cause and effect groups. The most influencing property is also identified. On the other hand, the considered Jute fiber lots are ranked using MABAC method along with the identification of the strengths and weaknesses of each of them.

This combined approach would provide a more scientific and realistic way of Jute grading and evaluation based on various properties of the considered Jute fiber lots. The positions of the superior and the inferior Jute lots perfectly match with those as identified by the earlier researchers.

It is concluded that the adopted combined decision-making tool can be effectively applied for grading and evaluation of other natural fibers with diverse heterogeneous physical properties.

In most developing countries riveting, upset forging and punching operations among others are performed using manual hammering technique. The use of the manual method increases production time and reduces efficiency. The use of the manual approach is predominantly due to the high cost of imported automated hammering machines (AHM) which the majority of the end-users are incapable of acquiring. The purpose of this paper, therefore, is to produce an AHM that is affordable using an effective material selection methodology in the design and fabrication process.

The material selection methodology proposed is the fuzzy multi-objective optimisation on the basis of the ratio analysis (MOORA) method. The tool was used to evaluate and determine the optimum material for the major of the components of the AHM from amongst alternative materials while considering several decision criteria. A case study of the shaft was applied to demonstrate the suitability of the proposed technique. The AHM components design is then carried out and machine fabricated and tested to ascertain performance effectiveness.

The result of the fuzzy MOORA evaluation showed that alloy steel is the optimal material for the shaft. The fuzzy MOORA approach was compared with the fuzzy Vlsekriterijumska Optimizacija Ikompromisno Resenje (VIKOR) and fuzzy grey relational analysis (GRA) methods to validate the proposed method. The fuzzy MOORA method produces completely the same result with the fuzzy VIKOR and fuzzy GRA methods. The machine was then designed, constructed and tested and found to be effective for the purpose of the design.

This is significant as no such study has been published by any other researcher to the best of our knowledge in this area.

The purpose of this paper is to explore the manner in which the degree of substitutability between public and private health expenditures contributes towards the distribution of wealth and political economy outcomes in the long run.

An overlapping generations model with heterogeneous agents where a person’s probability of survival into old age is determined by a variable elasticity of substitution (VES) health production function with public and private expenditures as inputs is developed. Public expenditure on health is determined through a political economy process.

Analytical and numerical results reveal that higher substitutability between private and public expenditures at the aggregate level and a higher share of public spending in the production of health lead to higher long run wealth levels and lower inequality. In the political equilibrium, higher aggregate substitutability between public and private health expenditures is associated with more tax revenue allocated towards public health. For most parameter combinations, the political economy and welfare maximising proportions of tax revenue allocated towards public health care converge in the long run.

The paper is a theoretical investigation of how substitutability between public and private health expenditures affect transitional and long run macroeconomic outcomes. These results are amenable to further empirical investigation.

The findings indicate that policies to improve institutional aspects that yield higher substitutability between public and private health expenditures and returns to public health spending could lead to better long run economic outcomes.

The results provide a political economy explanation for the low investments in public health care in developing countries, where aggregate substitutability between public and private health expenditures is likely to be lower. Furthermore, comparing the political economy and welfare maximising paradigms broadens the scope of the framework developed herein to provide potential explanations for cross-country differences in health outcomes.

This paper adopts an innovative approach to exploring this issue of substitutability in health expenditures by introducing a VES health production function. In an environment where agents have heterogeneous wealth endowments, this specification enables a distinction to be made between substitutability of these expenditures at the aggregate and individual levels, which introduces a rich set of dynamics that feeds into long run outcomes and political economy results.