K.B. Dada and E. Momoniat
The purpose of this paper is to derive a dynamic equation for modelling the behaviour of smectic‐C liquid crystals under the effect of an electric field.
Abstract
Purpose
The purpose of this paper is to derive a dynamic equation for modelling the behaviour of smectic‐C liquid crystals under the effect of an electric field.
Design/methodology/approach
The model equation is solved using a finite difference approximation, method of lines and pseudo‐spectral methods. The solutions are compared for accuracy and efficiency. Comparison is made of the efficiency of finite differences, method of lines and pseudo‐spectral methods.
Findings
The Fourier pseudo‐spectral method is shown to be the most efficient approach.
Originality/value
This work is original; a computational comparison of numerical schemes applied to liquid crystals has not been found in the literature.
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Moses Sunday Dada and Cletus Onwubuoya
The purpose of this paper is to consider heat and mass transfer on magnetohydrodynamics (MHD) Williamson fluid flow over a slendering stretching sheet with variable thickness in…
Abstract
Purpose
The purpose of this paper is to consider heat and mass transfer on magnetohydrodynamics (MHD) Williamson fluid flow over a slendering stretching sheet with variable thickness in the presence of radiation and chemical reaction. All pertinent flow parameters are discussed and their influence on the hydrodynamics, thermal and concentration boundary layer are presented with the aid of the diagram.
Design/methodology/approach
The governing partial differential equations are reduced into a system of ordinary differential equations with the help of suitable similarity variables. A discrete version of the homotopy analysis method (HAM) called the spectral homotopy analysis method (SHAM) was used to solve the transformed equations. SHAM is efficient, and it converges faster than the HAM. The SHAM provides flexibility when solving linear ordinary differential equations with the use of the Chebyshev spectral collocation method.
Findings
The findings revealed that an increase in the variable thermal conductivity hike the temperature and the thermal boundary layer thickness, whereas the reverse is the case for velocity close to the wall.
Originality/value
The uniqueness of this paper is the exploration of combined effects of heat and mass transfer on MHD Williamson fluid flow over a slendering stretching sheet. The Williamson fluid term in the momentum equation is expressed as a linear function and the viscosity and thermal conductivity are considered to vary in the boundary layer.
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James Temitope Dada, Folorunsho M. Ajide and Marina Arnaut
The purpose of this examine the impact of income inequality and shadow economy on environmental degradation given the growing income inequality, shadow economy and ecological…
Abstract
Purpose
The purpose of this examine the impact of income inequality and shadow economy on environmental degradation given the growing income inequality, shadow economy and ecological degradation in developing countries. Thus, this study is motivated to offer empirical insight into how income inequality and shadow economy influence the environment in African countries.
Design/methodology/approach
Data from 29 countries in Africa between 2000 and 2017 were used, while the novel method of moments quantile regression of Machado and Silva (2019) and Dumitrescu and Hurlin (D-H) (2012) granger causality is used as the estimation techniques.
Findings
The results established the presence of cross-sectional dependence and slope heterogeneity in the panel, while Westerlund panel cointegration confirmed the long-run cointegration among the variables. The results from the quantile regression suggest that income inequality increases environmental degradation from the 5th to the 30th quantiles, while from the 70th quantiles, income inequality reduces ecological degradation. The shadow economy negatively influences environmental degradation across the quantiles, strengthening environmental quality. Per capita income (economic growth) and financial development positively impact environmental degradation throughout the quantiles. However, urbanization reduces environmental degradation from 60th to 95th quantiles. The D-H causality established a two-way relationship between income inequality and environmental degradation, while one-way from shadow economy, per capita income and urbanization to environmental degradation were established.
Originality/value
This study provides fresh insights into the nexus between shadow economy and environmental quality in the presence of higher levels of income inequality for the case of African region. The study applies quantile analysis via moment proposed by Machado and Silva (2019). This technique shows that the impact of income inequality and shadow economy on environmental degradation is heterogeneous across the quantiles of ecological footprints in Africa.
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Tianzhuo Liu, WangBo Liu and Feng Yang
Based on the traditional buyback model, this paper aims to propose a new buyback method – the variable buyback contract – to solve the serious inventory backlog in the current…
Abstract
Purpose
Based on the traditional buyback model, this paper aims to propose a new buyback method – the variable buyback contract – to solve the serious inventory backlog in the current economic situation.
Design/methodology/approach
In this paper, the authors further study the buyback problem in a two-level supply chain with uncertain demand. Such a problem can be found in many research papers, which also use the Stackelberg game model. They put forward many factors that affect the buyback price, including risk preference, random arrival of consumers, etc. Different from the existing research, the authors propose another factor that may affect supply chain buyback – the retailer's remaining inventory to study the buyback contract.
Findings
First, the authors found that under the variable buyback contract, there is an optimal retail price, wholesale price and an optimal range of parameter settings for the buyback price. Second, the proposed Pareto-optimal solution for system improvement can achieve supply chain coordination. Third, under some conditions, the variable buyback contract is better than the wholesale price contract and fixed-price buyback contract.
Originality/value
First, this is the first paper to discuss to measure the buyback price with the retailer's remaining inventory. Second, the proposed buyback contract can help decision-makers to choose the optimal improvement strategies. Third, this contract has a certain practical significance, which can effectively alleviate the current inventory backlog problem.
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Information and communications technology (ICT) offers enormous opportunities for individuals, businesses and society. The application of ICT is equally important to economic and…
Abstract
Information and communications technology (ICT) offers enormous opportunities for individuals, businesses and society. The application of ICT is equally important to economic and non-economic activities. Researchers have increasingly focused on the adoption and use of ICT by small and medium enterprises (SMEs) as the economic development of a country is largely dependent on them. Following the success of ICT utilisation in SMEs in developed countries, many developing countries are looking to utilise the potential of the technology to develop SMEs. Past studies have shown that the contribution of ICT to the performance of SMEs is not clear and certain. Thus, it is crucial to determine the effectiveness of ICT in generating firm performance since this has implications for SMEs’ expenditure on the technology. This research examines the diffusion of ICT among SMEs with respect to the typical stages from innovation adoption to post-adoption, by analysing the actual usage of ICT and value creation. The mediating effects of integration and utilisation on SME performance are also studied. Grounded in the innovation diffusion literature, institutional theory and resource-based theory, this study has developed a comprehensive integrated research model focused on the research objectives. Following a positivist research paradigm, this study employs a mixed-method research approach. A preliminary conceptual framework is developed through an extensive literature review and is refined by results from an in-depth field study. During the field study, a total of 11 SME owners or decision-makers were interviewed. The recorded interviews were transcribed and analysed using NVivo 10 to refine the model to develop the research hypotheses. The final research model is composed of 30 first-order and five higher-order constructs which involve both reflective and formative measures. Partial least squares-based structural equation modelling (PLS-SEM) is employed to test the theoretical model with a cross-sectional data set of 282 SMEs in Bangladesh. Survey data were collected using a structured questionnaire issued to SMEs selected by applying a stratified random sampling technique. The structural equation modelling utilises a two-step procedure of data analysis. Prior to estimating the structural model, the measurement model is examined for construct validity of the study variables (i.e. convergent and discriminant validity).
The estimates show cognitive evaluation as an important antecedent for expectation which is shaped primarily by the entrepreneurs’ beliefs (perception) and also influenced by the owners’ innovativeness and culture. Culture further influences expectation. The study finds that facilitating condition, environmental pressure and country readiness are important antecedents of expectation and ICT use. The results also reveal that integration and the degree of ICT utilisation significantly affect SMEs’ performance. Surprisingly, the findings do not reveal any significant impact of ICT usage on performance which apparently suggests the possibility of the ICT productivity paradox. However, the analysis finally proves the non-existence of the paradox by demonstrating the mediating role of ICT integration and degree of utilisation explain the influence of information technology (IT) usage on firm performance which is consistent with the resource-based theory. The results suggest that the use of ICT can enhance SMEs’ performance if the technology is integrated and properly utilised. SME owners or managers, interested stakeholders and policy makers may follow the study’s outcomes and focus on ICT integration and degree of utilisation with a view to attaining superior organisational performance.
This study urges concerned business enterprises and government to look at the environmental and cultural factors with a view to achieving ICT usage success in terms of enhanced firm performance. In particular, improving organisational practices and procedures by eliminating the traditional power distance inside organisations and implementing necessary rules and regulations are important actions for managing environmental and cultural uncertainties. The application of a Bengali user interface may help to ensure the productivity of ICT use by SMEs in Bangladesh. Establishing a favourable national technology infrastructure and legal environment may contribute positively to improving the overall situation. This study also suggests some changes and modifications in the country’s existing policies and strategies. The government and policy makers should undertake mass promotional programs to disseminate information about the various uses of computers and their contribution in developing better organisational performance. Organising specialised training programs for SME capacity building may succeed in attaining the motivation for SMEs to use ICT. Ensuring easy access to the technology by providing loans, grants and subsidies is important. Various stakeholders, partners and related organisations should come forward to support government policies and priorities in order to ensure the productive use of ICT among SMEs which finally will help to foster Bangladesh’s economic development.
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Fernando Rojas and Victor Leiva
The objective of this paper is to propose a methodology based on random demand inventory models and dependence structures for a set of raw materials, referred to as “components”…
Abstract
Purpose
The objective of this paper is to propose a methodology based on random demand inventory models and dependence structures for a set of raw materials, referred to as “components”, used by food services that produce food rations referred to as “menus”.
Design/methodology/approach
The contribution margins of food services that produce menus are optimised using random dependent demand inventory models. The statistical dependence between the demand for components and/or menus is incorporated into the model through the multivariate Gaussian (or normal) distribution. The contribution margins are optimised by using probabilistic inventory models for each component and stochastic programming with a differential evolution algorithm.
Findings
When compared to the non-optimised system previously used by the company, the (average) expected contribution margin increases by 18.32 per cent when using a continuous review inventory model for groceries and uniperiodic models for perishable components (optimised system).
Research limitations/implications
The multivariate modeling can be improved by using (a) other non-Gaussian (marginal) univariate probability distributions, by means of the copula method that considers more complex statistical dependence structures; (b) time-dependence, through autoregressive time-series structures and moving average; (c) random modelling of lead-time; and (d) demands for components with values equal to zero using zero-inflated or adjusted probability distribution.
Practical implications
Professional management of the supply chain allows the users to register data concerning component identification, demand, and stock levels to subsequently be used with the proposed methodology, which must be implemented computationally.
Originality/value
The proposed multivariate methodology allows it to describe demand dependence structures through inventory models applicable to components used to produce menus in food services.
Propuesta
Este trabajo propone una metodología basada en modelos de inventarios con demanda aleatoria y estructura de dependencia para un conjunto de materias primas, denominadas “componentes”, usadas por servicios de alimentación que producen raciones alimenticias denominadas “menús”.
Diseño/Metodología
Los margen de contribución de servicios de alimentación que producen menús son optimizados empleando modelos de inventarios con demandas aleatorias dependientes. La dependencia estadística entre demandas de componentes y/o menús es incorporada en el modelado mediante la distribución gaussiana (o normal) multivariada. La optimización de los márgenes de contribución se logra usando modelos de inventarios probabilísticos para cada componente y programación estocástica mediante el algoritmo de evolución diferencial.
Resultados
El margen de contribución esperado (promedio) aumenta en un 18,32% usando modelos de inventario de revisión continua para abarrotes y modelos uniperiódicos para componentes perecederos (sistema optimizado), en relación al sistema no optimizado usado anteriormente por la compañía.
Originalidad
La metodología multivariada propuesta permite describir estructuras de dependencia de la demanda mediante modelos de inventario aplicables a componentes usados para producir menús en servicios de alimentación.
Implicancias prácticas
Una administración profesional de la gestión de la cadena de suministros permite registrar datos de la identificación del componente, su demanda y sus niveles de stock para ser usados posteriormente con la metodología propuesta, la que debe estar implementada computacionalmente.
Limitaciones
El modelado multivariado puede ser mejorado (a) utilizando distribuciones probabilísticas univariadas (marginales) distintas a la gaussiana, mediante métodos de cópulas que recojan estructuras de dependencia estadística más complejas; (b) considerando demandas de componentes con valores iguales a cero, mediante distribuciones probabilísticas infladas en cero; (c) usando dependencia temporal, mediante estructuras de series de tiempo autorregresivas y de media móvil, y (d) modelando el lead-time en forma aleatoria.
Details
Keywords
- Contribution margins
- Multivariate distribution
- Optimization methods
- Probabilistic inventory models
- Statistical dependence
- dependencia estadística
- distribuciones multivariantes
- márgenes de contribución
- modelos de inventarios probabilísticos
- métodos de optimización
- modelos de inventarios probabilísticos
James Temitope Dada, Folorunsho M. Ajide and Mamdouh Abdulaziz Saleh Al-Faryan
Driven by the Sustainable Development Goals (goals 7, 8, 12 and 13), this study investigates the moderating role of financial development in the link between energy poverty and a…
Abstract
Purpose
Driven by the Sustainable Development Goals (goals 7, 8, 12 and 13), this study investigates the moderating role of financial development in the link between energy poverty and a sustainable environment in African nations.
Design/methodology/approach
Panel cointegration analysis, fully modified least squares, Driscoll and Kraay least squares and method of moments quantile regression were used as estimation techniques to examine the link between financial development, energy poverty and sustainable environment for 28 African nations. Energy poverty is measured using two proxies-access to clean energy and access to electricity, while the environment is gauged using ecological footprint.
Findings
The regression outcomes show that access to clean energy and electricity negatively impacts the ecological footprint across all the quantiles; hence, energy poverty increases environmental degradation. Financial development positively influences environmental degradation in the region at the upper quantiles. Similarly, the interactive term of energy poverty and financial development has a significant positive impact on ecological footprint; thus, the financial sector adds to energy poverty and environmental degradation. The results of other variables hint that per capita income and institutions worsen environmental quality while urbanisation strengthens the environment.
Originality/value
This study offers fresh insights into the moderating effect of financial development in the link between energy poverty and sustainable environment in African countries.
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James Temitope Dada, Titus Ayobami Ojeyinka and Mamdouh Abdulaziz Saleh Al-Faryan
This paper investigates the (a)symmetric effects of financial development in the presence of economic growth, energy consumption, urbanization and foreign direct investment on…
Abstract
Purpose
This paper investigates the (a)symmetric effects of financial development in the presence of economic growth, energy consumption, urbanization and foreign direct investment on environmental quality of South Africa between 1980 and 2017.
Design/methodology/approach
A robust measure of financial development is generated using banking institutions and non-banking institutions market-based financial development indicators, while environmental quality is measured using carbon footprint, non-carbon footprint and ecological footprint. The objectives of the study are captured using linear and non-linear autoregressive distributed lag.
Findings
The result from the symmetric analysis suggests that financial development stimulates carbon footprint and ecological footprint in the short run; however, financial development abates non-carbon footprint. In the long run, financial development has a significant negative effect on carbon footprint and ecological footprint. However, the asymmetric analysis established strong asymmetric effect in the short run, while no asymmetric effect is found in the long run. The short run asymmetric analysis reveals that positive shock in financial development increases carbon footprint and ecological footprint; however, positive changes in financial development reduce non-carbon footprint. Negative shocks in financial development, on the other hand, have a positive impact carbon footprint, non-carbon footprint and ecological footprint.
Practical implications
The study's outcome implies that the concept of “more finance, more growth” could also be applied to “more finance, better environment” in South Africa. The study offers vital policy suggestions for the realization of sustainable development in South Africa.
Originality/value
This empiric adds to the body of knowledge on the influence of financial development on various components of environmental quality (carbon footprint, non-carbon footprint and ecological footprint) in South Africa.
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Hannes Velt and Rudolf R. Sinkovics
This chapter offers a comprehensive review the literature on authentic leadership (AL). The authors employ a bibliometric approach to identify, classify, visualise and synthesise…
Abstract
This chapter offers a comprehensive review the literature on authentic leadership (AL). The authors employ a bibliometric approach to identify, classify, visualise and synthesise relevant scholarly publications and the work of a core group of interdisciplinary scholars who are key contributors to the research on AL. They review 264 journal articles, adopting a clustering technique to assess the central themes of AL scholarship. They identify five distinct thematic clusters: authenticity in the context of leadership; structure of AL; social perspectives on AL; dynamism of AL; and value perceptions of AL. Velt and Sinkovics assert that these clusters will help scholars of AL to understand the dominant streams in the literature and provide a foundation for future research.
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Braye Henry Koroye and Olufunmilola Lola Dada
This study examines how cultural factors associated with women in plural families in the Southern parts of Nigeria affect the women’s entrepreneurial behaviours in their family…
Abstract
This study examines how cultural factors associated with women in plural families in the Southern parts of Nigeria affect the women’s entrepreneurial behaviours in their family businesses – higher education institutions (HEIs). There have been studies on women entrepreneurship, and the associated barriers, in family firms. However, the non-existence of studies on how cultural factors may affect women’s entrepreneurial behaviours in polygamous family firms poses a research gap. We seek to address this in this study, by using the term polygamous family firms in order to make a clear distinction from the traditional family firms that saturate several European countries and eslewhere. This study aims to understand how culture affects women’s entrepreneurial behaviours in polygamous family firms. Specifically, it shows how family belief systems and shared cultural norms influence women’s entrepreneurial behaviours in these firms. In this vein, we employed the case study strategy and used interviews and observations in our data collection process. Although polygamy is considered repressive in some cultures, this study’s findings reveal that it is a natural practice in Nigeria and not a dying tradition. We contribute to the literature on family firms and female entrepreneurship by showing the cultural hindrances to women empowerment within the polygamous family firm context. We provide theoretical and practical implications as well as future research agenda to encourage more studies on women’s entrepreneurial behaviours in polygamous family firms.