Search results

The purpose of this study is to investigate the natural convection characteristics of a reacting hybrid nanofluid in an open porous cavity bounded by vertical wavy walls subject to an inclined magnetic field.

The physical domain of the problem is constructed using coordinate transformations, and the equations are transformed accordingly. The resulting equations are then solved using finite difference method. Numerical results for the streamlines, isotherms and isoconcentration are illustrated with varying relevant parameters.

Whatever the values of parameters, streamlines have two counter-rotating cells, and their intensities are the highest near the open end. Moreover, the maximum temperature and the minimum concentration are obtained in close proximity to the open end. The strength of streamlines is increased with increasing Rayleigh number, Frank-Kamenetskii number and Darcy number, whereas it is decreased with the increment of volume fractions of nanoparticles.

The limitations of this study are that the model is suitable for thermal equilibrium cases and constant thermo-physical properties, while the results can predict two-dimensional flow behaviors.

To the best of the authors’ knowledge, there is no study on the natural convection induced by a chemical reaction in an open cavity bounded by vertical wavy walls. The findings might be used to gather knowledge about the flow, energy and reactant distributions in an open space containing a chemical reaction.

This study aims to numerically scrutinize the entropy generation minimization and mixed convective heat transfer of multi-walled carbon nanotubes–Fe₃O₄/water hybrid nanofluid flow in a lid-driven square enclosure with heat generation in the presence of a porous layer on inner surfaces, considering local thermal non-equilibrium (LTNE) approach and the non-Darcy flow model.

The dimensionless governing equations for hybrid nanofluid and solid phases are solved by applying the finite volume method and semi-implicit method for pressure-linked equations algorithm.

The roles of the internal heat generation in the porous layer, LTNE model and nanoparticles volume fraction on mixed convection phenomenon and entropy generation are introduced for lid-driven cavity hybrid nanofluid flow. Based on the investigation of entropy generation and heat transfer, the minimum total entropy generation and average Nusselt numbers are found at 1 ≤ Ri ≤ 10 where the effect of the forced and free convection flow directions being opposite each other is very significant. When considering various nanoparticle volume fractions, it becomes evident that the minimum entropy generation occurs in the case of φ = 0.1%. The outcomes of LTNE number reveal the operating parameters in which thermal equilibrium occurs between hybrid nanofluid and solid phases.

The analysis of entropy generation under various shear and buoyancy forces plays a significant role in the suitable thermal design and optimization of mixed convective heat transfer applications. This research significantly contributes to the optimization of design and the advancement of innovative solutions across diverse engineering disciplines, such as packed-bed thermal energy storage and thermal insulation.

This paper’s main aim is to check the mediating effect of supply chain memory in the relationship between using digital technologies and both supply chain resilience and robustness. In addition, the impact of the COVID-19 disruption was tested as a moderator of the impact of supply chain memory on supply chain resilience and robustness.

Altogether, 257 supply chain managers answered the questionnaire, and data were analysed through structural equation modelling.

This paper contributes to theory and practice by demonstrating that the experience, familiarity and knowledge to deal with disruptions partially mediate the relationship between digital technologies, resilience and robustness. Moreover, our results show that memory is less efficient for the supply chain to maintain an acceptable level of performance in case of a new extreme disruptive event like COVID-19. The full model was able to explain 36.90% of supply chain memory, 41.58% of supply chain resilience and 46.21% of supply chain robustness.

The study helps to understand how to develop supply chain memory, positioning digital technologies as an antecedent of it. The impact of supply chain memory on supply chain resilience and robustness is proved. Knowledge about the impact of industry 4.0 technologies on disruption management is quantitatively improved. It demonstrates that digital technologies impact resilience and robustness mainly through supply chain memory. The study proves that supply chain memory is less efficient for the chain remains effective when a non-routine disruptive event occurs, but it is still imperative to recover from it.

A porous cavity flow field generates entropy owing to energy and momentum exchange within the fluid and at solid barriers. The heat transport and viscosity effects on fluid and solid walls irreversibly generate entropy. This numerical study aims to investigate convective heat transfer together with entropy generation in a partially heated wavy porous cavity filled with a hybrid nanofluid.

The governing equations are nondimensionalized and the domain is transformed into a unit square. A second-order finite difference method is used to have numerical solutions to nondimensional unknowns such as stream function and temperature. This numerical computation is conducted to explore a wide range of regulating parameters, e.g. hybrid nano-particle volume fraction (σ = 0.1%, 0.33%, 0.75%, 1%, 2%), Rayleigh–Darcy number (Ra = 10, 10², 10³), dimensionless length of the heat source (ϵ = 0.25, 0.50,1.0) and amplitude of the wave (a = 0.05, 0.10, 0.15) for a number of undulations (N = 1, 3) per unit length.

A thorough analysis is conducted to analyze the effect of multiple factors such as thermal convective forces, heat source, surface corrugation factors, nanofluid volume fraction and other parameters on entropy generation. The flow and temperature fields are studied through streamlines and isotherms. The average Bejan number suggested that entropy generation is entirely dominated by irreversibility due to heat transport at Ra = 10, and the irreversibility due to the viscosity effect is severe at Ra = 10³, but the increment in s augments irreversibility due to the viscosity effect over the heat transport at Ra = 10².

To the best of the authors’ knowledge, this numerical study, for the first time, analyzes the influence of surface corrugation on the entropy generation related to the cooling of a partial heat source by the convection of a hybrid nanofluid.

The objective of this study is to examine current business and management research on “Industry 4.0 base technologies” and “business models” to shed light on this vast literature and to point out future research agenda.

The authors conducted a bibliometric analysis of scientific publications based on 482 documents collected from the Scopus database and a co-citation analysis to provide an overview of business model studies related to Industry 4.0 base technologies. After that a qualitative analysis of the articles was also conducted to identify research trends and trajectories.

The results reveal the existence of five research themes: smart products (cluster 1); business model innovation (cluster 2); technological platforms (cluster 3); value creation and appropriation (cluster 4); and digital business models (cluster 5). A qualitative analysis of the articles was also conducted to identify research trends and trajectories.

First, the dataset was collected through Scopus. The authors are aware that other databases, such as Web of Science, can be used to deepen the focus of quantitative bibliometric analysis. Second, the authors based this analysis on the Industry 4.0 base technologies identified by Frank et al. (2019). The authors recognize that Industry 4.0 comprises other technologies beyond IoT, cloud computing, big data and analytics.

Drawing on these analyses, the authors submit a useful baseline for developing Industry 4.0 base technologies and considering their implications for business models.

In this paper, the authors focus their attention on the relationship between technologies underlying the fourth industrial revolution, identified by Frank et al. (2019), and the business model, with a particular focus on the developments that have occurred over the last decade and the authors performed a bibliometric analysis to consider all the burgeoning literature on the topic.

The purpose of the present article is to obtain the similarity solution for the shock wave generated by a piston propagating in a self-gravitating nonideal gas under the impact of azimuthal magnetic field for adiabatic and isothermal flows.

The Lie group theoretic method given by Sophus Lie is used to obtain the similarity solution in the present article.

Similarity solution with exponential law shock path is obtained for both ideal and nonideal gas cases. The effects on the flow variables, density ratio at the shock front and shock strength by the variation of the shock Cowling number, adiabatic index of the gas, gravitational parameter and nonidealness parameter are investigated. The shock strength decreases with an increase in the shock Cowling number, nonidealness parameter and adiabatic index, whereas the strength of the shock wave increases with an increase in gravitational parameter.

Propagation of shock wave with spherical geometry in a self-gravitating nonideal gas under the impact of azimuthal magnetic field for adiabatic and isothermal flows has not been studied by any author using the Lie group theoretic method.

Firms are increasingly required to make ethical choices when selecting suppliers for their supply chains, and the decisions often rest on individual purchasing managers within the firm. This study builds on the literature on ethical decision-making and the concept of decision frames to investigate the decision-making process of purchasing managers in financially distressed firms. Codes of Conduct (CoC) and how they are enforced (financial rewards and codified procedures for oversight) are studied in terms of their effectiveness in informing and guiding purchasing managers in their supplier selection decisions.

Four sequential experiments were conducted with a total of 648 purchasing managers from manufacturing firms.

The results indicate that purchasing managers in firms facing financial distress are more than four times more likely than purchasing managers in the control groups to select the less ethical supplier in favor of better operational performance. As a potential remedy, it is found that enforcing the firm's CoC help to counteract this tendency and increase ethical supplier selection decisions by 2.1- to 2.6-fold. However, CoC enforcement that invokes multiple conflicting decision frames simultaneously is more likely to impair than promote ethical supplier selection decisions, compared to situations where only one enforcement method is present.

These findings develop an improved understanding of purchasers' decision-making processes and shed light on how to effectively use CoCs to guide these decisions.

This research paper aims to investigate detailed relationships between market selection and product positioning decisions and their associated short- and long-term product performance outcomes in the context of the music category: a cultural goods industry with high amounts of product introductions. Market selection decisions are defined by the size, competitiveness and age of market subcategories within an overall product category. Positioning decisions include where a product’s attributes are located spatially in the category (periphery versus the market center), whether a product resides within a single subcategory or spans multiple ones and what brand strategy (single versus co-branding) is used.

Data are from multiple sources for the US music industry (aka product category) from 1958 to 2019 to empirically test the hypotheses: genres (rock, blues, etc.) correspond to subcategories; artists to brands; and songs to products. Regression analyses are used.

A complex set of nuanced results are generated and reported, finding that key marketing decisions drive short-term new product success differently and frequently in opposing ways than long-term success. Launching into very new, well-established or very competitive markets leads to the strongest long-term success, despite less attractive short-run prospects. Positioning a product away from the market center and spanning subcategories similarly poses short-run challenges, but long-run returns. Brand collaborations have reverse effects. Short-run product success is found, overall, to be difficult to predict even with strong data inputs, which has substantial implications for how firms should manage portfolios of products in cultural goods industries. Long-run product success is considerably more predictable after short-run success is observed and accounted for.

While managers and firms in cultural goods industries have long relied on intuition to manage market selection and product positioning decisions, this research tests the hypothesis that objective data inputs and empirical modeling can better predict short- and long-run success of launched products. Specific insights on which song characteristics may be associated with success are found – as are more generalizable, industry-level results. In addition, by distinguishing between short- and long-run success, a more complete picture on how key decisions holistically affect product performance emerges. Many market selection and product positioning decisions have differential impacts across these two frames of reference.