This paper provides a self-contained introduction to the mathematical aspects of the topological derivative.
Abstract
Purpose
This paper provides a self-contained introduction to the mathematical aspects of the topological derivative.
Design/methodology/approach
Full justifications are given on simple model problems following a modern approach based on the averaged adjoint state technique. Extensions are discussed in relation with the literature on the field.
Findings
Closed expressions of topological derivatives are obtained and commented.
Originality/value
Several cases are covered in a unified and didactic presentation. Some elements of proof are novel.
Details
Keywords
Deborah N. Brewis and Sarah Taylor Silverwood
Annotation is a practice that is familiar to many of us, and yet it is a practice so natural that it is hard to pin down its characteristics, to find where its edges are, and…
Abstract
Annotation is a practice that is familiar to many of us, and yet it is a practice so natural that it is hard to pin down its characteristics, to find where its edges are, and identify what it does for us. In this piece, we use reflections on the practices of annotation in four fields of work: academia, software engineering, medical sonography and visual art as a point of departure to theorise annotation as a set of practices that bridge reading, writing and thinking. We think about annotation being performative and consider what and how it brings into being. Revealing hidden practices in our working lives, such as annotation, helps us to understand how knowledge comes to be created, disseminated, legitimated and popularised. To this end, we make the practices of annotation involved in writing the present piece visible in an effort to write differently in management and organisation studies, unpicking and exposing it as ever dialogical and unfinished.
Details
Keywords
J. Batina, M. Batchi, S. Blancher, R. Creff and C. Amrouche
The purpose of this paper is to analyse the convective heat transfer of an unsteady pulsed, laminar, incompressible flow in axisymmetric tubes with periodic sections. The flow is…
Abstract
Purpose
The purpose of this paper is to analyse the convective heat transfer of an unsteady pulsed, laminar, incompressible flow in axisymmetric tubes with periodic sections. The flow is supposed to be developing dynamically and thermally from the duct inlet. The wall is heated at constant and uniform temperature.
Design/methodology/approach
The problem is written with classical homogeneous boundary conditions. We use a shift operator to impose non‐homogeneous boundary conditions. Consequently, this method introduces source terms in the Galerkin formulation. The momentum equations and the energy equation which govern this problem are numerically solved in space by a spectral Galerkin method especially oriented to this situation. A Crank‐Nicolson scheme permits the resolution in time.
Findings
From the temperature field, the heat transfer phenomenon is presented, discussed and compared to those obtained in straight cylindrical pipes. This study showed the existence of zones of dead fluid that locally have a negative influence on heat transfer. Substantial modifications of the thermal convective heat transfer are highlighted at the entry and the minimum duct sections.
Practical implications
Pulsated flows in axisymmetric geometries can be applied to medical industries, mechanical engineering and technological processes.
Originality/value
One of the original features of this study is the choice of Chebyshev polynomials basis in both axial and radial directions for spectral methods, combined with the use of a shift operator to satisfy non‐homogeneous boundary conditions.
Details
Keywords
Asha Shivappa Kotnurkar and Deepa C. Katagi
The current paper investigates the bioconvective third-grade nanofluid flow containing gyrotactic organisms with Copper-blood nanoparticles in permeable walls.
Abstract
Purpose
The current paper investigates the bioconvective third-grade nanofluid flow containing gyrotactic organisms with Copper-blood nanoparticles in permeable walls.
Design/methodology/approach
The equations governing the flow are solved by adopting the Adomian decomposition method.
Findings
The results show that the biconvection Peclet number decreases the density of motile microorganisms, and the Rayleigh number also decreases the velocity profile.
Practical implications
The present study can be applied to design the higher generation microsystems.
Originality/value
To the best of the authors’ knowledge, no such investigation has been carried out in the literature.
Details
Keywords
Maria Hvid Dille and Mie Plotnikof
While recent theoretical discussions around discourse–material relationality have facilitated important conceptual and analytical advancements within the broader field of CMS…
Abstract
Purpose
While recent theoretical discussions around discourse–material relationality have facilitated important conceptual and analytical advancements within the broader field of CMS, less progress has been made methodologically with regard to innovating empirical methods and data modes. Therefore, the purpose of this article is to contribute to strengthening the methodological focus in the literature when grappling with the relationality of discourse–materiality and co-constitution. This includes a method-retooling framework inspired by new materialism.
Design/methodology/approach
In this article, the authors engage at the methodological level by developing a method-retooling framework that combines insights from organizational discourse studies and new materialist thinking. This framework enables a retooling of existing methods to become sensitive to multimodality and offers two concrete examples that were developed during fieldwork for a multi-sited and multi-method case study in 2018.
Findings
Based on the framework for retooling methods for multimodality, two illustrations are offered. These include retooling interviews by employing multimodal vignettes and retooling observations by using multimodal mappings. They are unfolded and discussed regarding their appropriation of discourse–material relationality.
Originality/value
This paper includes original research and method developments – adding a critical focus on the methodological aspects and potential advancements that are necessary in the wake of the ongoing debates around discourse–materiality across CMS and specifically within studies of organizational discourse and CCO. By suggesting a framework, the authors stimulate methodological explorations and contribute to furthering method developments that are equal to the rich conceptual progress made within the field.
Details
Keywords
Jean Batina, Serge Blancher and Tarik Kouskou
Mathematical and numerical models are developed to study the melting of a Phase Change Material (PCM) inside a 2D cavity. The bottom of the cell is heated at constant and uniform…
Abstract
Purpose
Mathematical and numerical models are developed to study the melting of a Phase Change Material (PCM) inside a 2D cavity. The bottom of the cell is heated at constant and uniform temperature or heat flux, assuming that the rest of the cavity is completely adiabatic. The paper used suitable numerical methods to follow the interface temporal evolution with a good accuracy. The purpose of this paper is to show how the evolution of the latent energy absorbed to melt the PCM depends on the temperature imposed on the lower wall of the cavity.
Design/methodology/approach
The problem is written with non-homogeneous boundary conditions. Momentum and energy equations are numerically solved in space by a spectral collocation method especially oriented to this situation. A Crank-Nicolson scheme permits the resolution in time.
Findings
The results clearly show the evolution of multicellular regime during the process of fusion and the kinetics of phase change depends on the boundary condition imposed on the bottom cell wall. Thus the charge and discharge processes in energy storage cells can be controlled by varying the temperature in the cell PCM. Substantial modifications of the thermal convective heat and mass transfer are highlighted during the transient regime. This model is particularly suitable to follow with a good accuracy the evolution of the solid/liquid interface in the process of storage/release energy.
Research limitations/implications
The time-dependent physical properties that induce non-linear coupled unsteady terms in Navier-Stokes and energy equations are not taken into account in the present model. The present model is actually extended to these coupled situations. This problem requires smoother geometries. One can try to palliate this disadvantage by constructing smoother approximations of non-smooth geometries. The augmentation of polynomials developments orders increases strongly the computing time. When the external heat flux or temperature imposed at the PCM is much greater than the temperature of the PCM fusion, one must choose carefully some data to assume the algorithms convergence.
Practical implications
Among the areas where this work can be used, are: buildings where the PCM are used in insulation and passive cooling; thermal energy storage, the PCM stores energy by changing phase, solid to liquid (fusion); cooling and transport of foodstuffs or pharmaceutical or medical sensitive products, the PCM is used in the food industry, pharmaceutical and medical, to minimize temperature variations of food, drug or sensitive materials; and the textile industry, PCM materials in the textile industry are used in microcapsules placed inside textile fibres. The PCM intervene to regulate heat transfer between the body and the outside.
Originality/value
The paper's originality is reflected in the precision of its results, due to the use of a high-accuracy numerical approximation based on collocation spectral methods, and the choice of Chebyshev polynomials basis in both axial and radial directions.
Details
Keywords
Ahmed Khadhraoui and Cherif Adnen
The purpose of this study is to present a new approach of a hydrogen-based green energy supply system intended for powering electric vehicles using fuel cells (FCs) and suitable…
Abstract
Purpose
The purpose of this study is to present a new approach of a hydrogen-based green energy supply system intended for powering electric vehicles using fuel cells (FCs) and suitable for sustainable urban automobile transportations.
Design/methodology/approach
To resolve the problems with current electric vehicles, which are cost, autonomy and charging infrastructure, the authors have developed in this study a new prototype which uses an autonomous hydrogen production system, embedded in the vehicle and assisted by a photovoltaic source and ion-lithium batteries. The on-board produced hydrogen is then used by a reversible FC (PEMFC) to generate electricity to power the vehicle engine.
Findings
The obtained results demonstrated that the FC could provide approximately 70% of the required current once the vehicle was in motion, with the remaining 30% supplied by the battery. The carbon dioxide (CO2) emissions were reduced of 98%.
Research limitations/implications
A most vehicles use an internal combustion engine causing serious air pollution and the inability to meet new clean energy standards with zero CO2 emissions. In this same context, hybrid vehicles produce at least 80 g of CO2 every km, which is much higher than the Kyoto, Copenhagen and Paris COP21 policies.
Social implications
This study will help to create the best ecological ecosystem with low greenhouse emissions.
Originality/value
This concept offers many advantages, such as increased range, reduced recharge time, increasing the system autonomy and no CO2 emissions, which contribute to reducing air pollution, regulation with CE protocols and moving toward cleaner and more sustainable mobility.
Details
Keywords
Jiaquan Yang, Jinyu Fang and Jiafu Su
This paper aims to identify the conditions under which encroachment is a viable strategy for a manufacturer to gain competitive advantage and achieve higher profitability in the…
Abstract
Purpose
This paper aims to identify the conditions under which encroachment is a viable strategy for a manufacturer to gain competitive advantage and achieve higher profitability in the presence of the store-brand.
Design/methodology/approach
This paper proposes game-theoretic models in a two-echelon supply chain consisting of a manufacturer (him) and a retailer (her), in which he distributes his national brand through the retailer, and endogenously determines whether to establish a new direct sales channel to sell the national brand when the retailer introduces her store-brand.
Findings
Analytical results show that the bar for the manufacturer to encroach the end market in the presence of the store-brand is always higher than that for him to encroach in the absence of the store-brand. Although incurring channel competition, encroaching with the national brand in the presence of the retailer's store-brand can lead to either a win-lose or win-win result for the manufacturer and the retailer. Numerical studies claim that, higher brand substitution can push down the retailer's enthusiasm to introduce her new brand. Counterintuitively, when the retailer introduces her store-brand, higher brand substitution does not necessarily push up the manufacturer's enthusiasm to respond with national-brand encroachment. When consumer preferences for the two brands are heterogeneous, a higher consumer preference for the retailer's store-brand results in the retailer's higher enthusiasm to introduce her store-brand and the manufacturer's lower enthusiasm to encroach with his national brand.
Originality/value
This study can help researchers to better understand the retailer's store-brand introduction, manufacturer encroachment and their interaction theoretically, and further provide decision support for enterprises to choose brand and channel strategies in practice.
Details
Keywords
The purpose of this paper is to investigate the impact of wholesale price discrimination by a manufacturer in a retailer–e-tailer dual-channel supply chain for different product…
Abstract
Purpose
The purpose of this paper is to investigate the impact of wholesale price discrimination by a manufacturer in a retailer–e-tailer dual-channel supply chain for different product categories based on their online channel preference.
Design/methodology/approach
This paper considers a dual-channel supply chain comprising of a retailer and an e-tailer engaged in competition. Game-theoretic models are developed to model the competition between the retailer and e-tailer and to derive their optimal price, optimal order quantity and optimal profit under (1) equal wholesale price strategy and (2) discriminatory wholesale price strategy. Further, a numerical example was employed to quantify the results and to capture the variation with respect to online channel preference of the product.
Findings
It is beneficial for the manufacturer to adopt a discriminatory wholesale price strategy for products having both high online channel preference and low online channel preference. However, equal wholesale price strategy is beneficial for the e-tailer and the retailer in the case of products having high online channel preference and in the case of products having low online channel preference, respectively.
Practical implications
The study helps the manufacturers to maximize their profit by adopting the right wholesale price strategy considering the online channel preference of the product when the manufacturers are supplying to heterogeneous retailers.
Originality/value
There is scant literature on the wholesale price strategy of the manufacturer considering the heterogeneous downstream retailers. This paper contributes the literature by bridging this gap. In addition, the study establishes a link between the wholesale price strategy and online channel preference of the product.
Details
Keywords
Pratima Jeetah, Yasser M Chuttur, Neetish Hurry, K Tahalooa and Danraz Seebun
Mauritius is a Small Island Development State (SIDS) with limited resources, and it has been witnessed that many containers used for storing household and industrial products are…
Abstract
Mauritius is a Small Island Development State (SIDS) with limited resources, and it has been witnessed that many containers used for storing household and industrial products are made from plastic. When discarded as waste, those plastic containers pose a serious environmental and economic challenge for Mauritius. Moreover, landfill space is getting increasingly scarce, and plastic waste is contaminating both land and water. Therefore, it is of the utmost necessity to develop solutions for Mauritius' plastic wastes. Due to its abundance and accessibility, plastic waste is a promising material for recycling and energy production. One potential solution is the use of machine learning and artificial intelligence (AI) to predict household plastic consumption, allowing policymakers to design effective strategies and initiatives to reduce plastic waste. Such information is a critical component to be able to efficiently plan for the collection and routing of trucks when collecting recyclable plastics. The development of new strategies for the recycling of plastic waste and development of new industry can address the import and export potential of the country to achieve self-sustainability as well as contribute to reduction in plastic pollution and amount of waste landfilled. These plastics can thereafter be used effectively for recycling and for the making of 3D printing filaments which fall under the SDGs 9 (Industry, Innovation and Infrastructure) and 12 (Responsible consumption and production).