Khairunnahar Suchana and Md. Mamun Molla
The present numerical investigation examines the magnetohydrodynamic (MHD) double diffusion natural convection of power-law non-Newtonian nano-encapsulated phase change materials…
Abstract
Purpose
The present numerical investigation examines the magnetohydrodynamic (MHD) double diffusion natural convection of power-law non-Newtonian nano-encapsulated phase change materials (NEPCMs) in a trapezoidal cavity.
Design/methodology/approach
The governing Navier-Stokes, energy and concentration equations based on the Cartesian curvilinear coordinates are solved using the collocated grid arrangement’s finite volume method. The in-house FORTRAN code is validated with the different benchmark problems. The NEPCM nanoparticles consist of a core-shell structure with Phase Change Material (PCM) at the core. The enclosure, shaped as a trapezoidal hollow, features a warmed (Th) left wall and a cold (Tc) right wall. Various parameters are considered, including the power law index (0.6 ≤ n ≤ 1.4), Hartmann number (0 ≤ Ha ≤ 30), Rayleigh number (104 ≤ Ra ≤ 105) and fixed variables such as buoyancy ratio (Br = 0.8), Prandtl number (Pr = 6.2), Lewis number (Le = 5), fusion temperature (Θf = 0.5) and volume fraction (ϕ = 0.04).
Findings
The findings indicate a decrease in local Nusselt (Nu) and Sherwood (Sh) numbers with increasing Hartmann numbers (Ha). Additionally, for a shear-thinning fluid (n = 0.6) results in the maximum local Nu and Sh values. As the Rayleigh number (Ra) increases from 104 to 105, the structured vortex in the streamline pattern is disturbed. Furthermore, for different Ra values, an increase in n from 0.6 to 1.4 leads to a 67.43% to 76.88% decrease in average Nu and a 70% to 77% decrease in average Sh.
Research limitations/implications
This research is for two-dimensioal laminar flow only.
Practical implications
PCMs represent a class of practical substances that behave as a function of temperature and have the innate ability to absorb, release and store heated energy in the form of hidden fusion enthalpy, or heat. They are valuable in these systems as they can store significant energy at a relatively constant temperature through their latent heat phase change.
Originality/value
As per the literature review and the authors’ understanding, an examination has never been conducted on MHD double diffusion natural convection of power-law non-Newtonian NEPCMs within a trapezoidal enclosure. The current work is innovative since it combines NEPCMs with the effect of magnetic field Double diffusion Natural Convection of power-law non-Newtonian NEPCMs in a Trapezoidal enclosure. This outcome can be used to improve thermal management in energy storage systems, increasing safety and effectiveness.
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Mamun Molla, Suvash C. Saha and M.A.I. Khan
The purpose of this paper is to discuss, with numerical simulations, magnetohydrodynamic (MHD) natural convection laminar flow from an isothermal horizontal circular cylinder…
Abstract
Purpose
The purpose of this paper is to discuss, with numerical simulations, magnetohydrodynamic (MHD) natural convection laminar flow from an isothermal horizontal circular cylinder immersed in a fluid with viscosity proportional to a linear function of temperature.
Design/methodology/approach
The governing boundary layer equations are transformed into a non‐dimensional form and the resulting nonlinear system of partial differential equations are reduced to convenient form, which are solved numerically by two very efficient methods: implicit finite difference method together with Keller box scheme; and direct numerical scheme.
Findings
Numerical results are presented by velocity and temperature distributions of the fluid as well as heat transfer characteristics, namely the shearing stress and the local heat transfer rate in terms of the local skin‐friction coefficient and the local Nusselt number for a wide range of MHD parameter, viscosity‐variation parameter and viscous dissipation parameter.
Originality/value
MHD flow in this geometry with temperature dependent viscosity is absent in the literature. IN this paper, the results obtained from the numerical simulations have been verified by two methodologies.
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To investigate the effects of chemical reaction on natural convection heat and mass transfer from a sphere with temperature dependent viscosity.
Abstract
Purpose
To investigate the effects of chemical reaction on natural convection heat and mass transfer from a sphere with temperature dependent viscosity.
Design/methodology/approach
The governing boundary layer equations are transformed into a non‐dimensional form and the resulting nonlinear system of partial differential equations are reduced to local non‐similarity boundary layer equations, which are solved numerically by very efficient implicit finite difference method together with Keller box scheme.
Findings
The effects of chemical reaction, the skin‐friction coefficients, surface heat transfer rates, velocity and concentration distribution decrease as well as the mass transfer rates and temperature distribution increase within the boundary layer.
Research limitations/implications
The investigation is valid for steady two‐dimensional laminar flow. The concentration of the reactant is maintained at a constant value and the sphere is isothermal. An extension to unsteady flow with temperature dependent thermal conductivity is left for future work.
Originality/value
This result provides guidance to engineers about heat and mass transfer with the effects of chemical reaction from isothermal spherical surface.
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Mahfuz Ashraf, Helena Grunfeld, Md. Rakibul Hoque and Khorshed Alam
Information and communication technologies (ICTs) have received much attention as a tool for development for several decades. One way in which ICTs were introduced in developing…
Abstract
Purpose
Information and communication technologies (ICTs) have received much attention as a tool for development for several decades. One way in which ICTs were introduced in developing countries, particularly prior to the advent of smartphones, was through shared access and information centres. Many of these were established as pilots, but were unable to operate without external funding and were often declared failures. And some of them probably were, particularly those that focussed exclusively on ICT as a technology, rather than on how the centres could contribute to improving livelihoods. The purpose of this paper is to explore how some centres, namely “Bangladesh Rural Advancement Committee (BRAC) Gonokendra” in three villages of Bangladesh, influenced socio-economic development.
Design/methodology/approach
This study was informed by the Heeks and Molla’s extended information chain model and Sen’s “development as freedom”. The field study was undertaken in three BRAC Gonokendras located in different villages in rural Bangladesh.
Findings
While the authors found that the centres contributed to socio-economic development, this contribution was limited by social constraints, hindering the well-being of individuals and families. Addressing social constraints thus remains a challenge in order for ICTs to contribute to development.
Originality/value
The extended framework to investigate ICT-led socio-economic development implies that ICT as a catalyst can promote development at micro/community level only by simultaneously addressing social constraints.
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Risk factors for population relocation as a result of severe catastrophes are increasing on a global scale. The frequency of catastrophic weather events is rising, infrastructure…
Abstract
Risk factors for population relocation as a result of severe catastrophes are increasing on a global scale. The frequency of catastrophic weather events is rising, infrastructure is getting older, the population is expanding, and urbanization is increasing. This study explores the influencing factors of livelihood, vulnerability, and livelihood resilience of climate-induced displaced people in developing countries, particularly in South Asia. A mixed-method approach comprising a systematic review and a narrative review has been applied in this study. A systematic review guided by PRISMA has been used to identify the relevant documents and the extracted information has been described through a narrative review approach. This study reveals that climate-induced displaced people are generally vulnerable to maintaining their livelihood, but there are a few exceptional cases where displaced people could diversify their livelihood strategies. The major influencing factors of their livelihoods are riverbank erosion, loss of assets and properties, food insecurity, seasonal hunger, low access to finance, and low job opportunity. This study argues that climate-displaced people have a long struggle to enhance their livelihood resilience, but it is a challenging task for them, particularly at the household level. The major influencing indicators under adaptive, absorptive, and transformative capacities of livelihood resilience are income and food access, agricultural and non-agricultural assets, sensitivity, climate variability and hazards, basic services, social safety nets, and institutional participation. Appropriate governance in the structural and non-structural transformation of livelihood capitals can enhance the livelihood resilience of climate-induced displaced households. In the case of Bangladesh, the coastal and Riverine Island communities are the key victims of climate-induced hazards, so they migrated frequently to reduce their vulnerability and enhance livelihood resilience. The study recommends ensuring transparency and accountability, proper coordination among stakeholders for promoting the resettlement, disaster-resilient housing and infrastructure, and Khas land (government-owned land) to the displaced people can enhance their livelihood resilience.
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Nazamul Hoque, Mahi Uddin, Mohammad Tazul Islam, Abdullahil Mamun, Mohammad Nazim Uddin, Afzal Ahmad and Md Thowhidul Islam
This study looked into the scope of integrating the aspirations of zakah and corporate social responsibility (CSR) to counter poverty, inequity, illiteracy, malnutrition and…
Abstract
Purpose
This study looked into the scope of integrating the aspirations of zakah and corporate social responsibility (CSR) to counter poverty, inequity, illiteracy, malnutrition and environmental pollution to ensure peace, happiness, prosperity and sustainability as envisaged in sustainable development goals (SDGs).
Design/methodology/approach
This is a qualitative research study conducted using both primary and secondary data. Primary data were collected from 29 business enterprises in Bangladesh employing a semi-structured interview protocol. The secondary data were collected through content analysis of annual reports, websites and CSR publications of sample organizations. Finally, collected qualitative data have been analyzed thematically following the due procedures to address the research questions.
Findings
The findings reveal that integration of the aspirations of zakah and CSR is a convenient and wholehearted approach for entrepreneurs resulting in pursuing SDGs. In addition, business entrepreneurs in Bangladesh consider such practices as killing two birds with one stone because this approach warrants performing both religious and social obligations simultaneously. Interestingly, the study explores that shariah compliance acts as a guiding force for selecting well-being-oriented projects in zakah-funded CSR resulting in pursuing the priority goals – No Poverty (1), Zero Hunger (2) – of SDGs, thereby addressing some of the most critical issues of emerging economies such as Bangladesh.
Practical implications
The findings of this research can be used as a guide to incorporate the spirit and principle of zakah into the CSR programs aimed at pursuing SDGs mainly in Muslim countries representing one-fourth of the world population.
Originality/value
Integration of the aspirations of zakah and CSR is an innovative move and net addition to the literature on sustainability, CSR and zakah because Muslim business entrepreneurs will now conveniently be able to use the entrepreneurs' zakah money – readily available in each financial year – to fund the entrepreneurs' various CSR projects (within shariah framework) relating to poverty alleviation, humanitarian and disaster relief, health and sanitation and environmental conservation which will eventually contribute to pursuing various SDGs.
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Md. Wasiul Islam, Md. Mahfuz Ur Rahman and Shakil Ahmed
Visits to locations connected to historical atrocities, tragedy, suffering, or presumably dreadful events are referred to as “dark tourism”. While Bangladesh may not be widely…
Abstract
Visits to locations connected to historical atrocities, tragedy, suffering, or presumably dreadful events are referred to as “dark tourism”. While Bangladesh may not be widely known for dark tourism, several unexplored avenues may be of interest to those who engage in this type of unique and unconventional tourism experience. In addition to creating job opportunities and income generation in Bangladesh, it can achieve educational objectives, communicate with a broad audience, raise awareness of events of the past, and quench people's thirst for information, which can help them to comprehend a society. Though Bangladesh has several somber locations connected to tragic events including World War II, liberation war sites, mass killing sites, shipbreaking yards, Rohingya refugee camps, riots, and the mother language movement, traditional tourism predominates there. If managed responsibly, these varied resources, somber locations, and histories, some of which date back to 1800, could make Bangladesh a dark tourism destination. Although dark tourism in Bangladesh has the potential to contribute to historical awareness, preservation, educational opportunities, and socioeconomic development, it is yet unexplored due to a lack of knowledge, experience, policy, effective marketing, and some controversies. By approaching responsibly, Bangladesh can leverage its history to attract visitors' interests in exploring the darker aspects of the country's past. Hence, this chapter is designed to explore the status and potential significance, prospects, and challenges of dark tourism in Bangladesh. The findings will help policymakers, tourists, and other stakeholders to explore and enjoy enormous benefits from Bangladesh's untapped dark tourism opportunities.
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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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M. Hassanein, M. Abd El Rahm, H. M. Abd El Bary and H. Abd El-Wahab
This paper aims to study the physical and chemical characteristics of inkjet titanium dioxide inks for cotton fabric digital printing.
Abstract
Purpose
This paper aims to study the physical and chemical characteristics of inkjet titanium dioxide inks for cotton fabric digital printing.
Design/methodology/approach
Different dispersing agents through the reaction of glycerol monooleate and toluene diisocyanate were prepared and then performed by using three different polyols (succinic anhydride-modified polyethylene glycol PEG 600, EO/PO Polyether Monoamine and p-chloro aniline Polyether Monoamine), to obtain three different dispersing agents for water-based titanium dioxide inkjet inks. The prepared dispersants were characterized using FTIR to monitor the reaction progress. Then the prepared dispersants were formulated in titanium dioxide inkjet inks formulation and characterized by particle size, dynamic surface tension, transmission electron microscopy, viscosity and zeta potential against commercial dispersants. Also, the study was extended to evaluate the printed polyester by using the prepared inks according to washing and crock fastness.
Findings
The obtained results showed that p-chloro aniline Polyether Monoamine (J) and succinic anhydride modified polyethylene glycol PEG 600 (H) dispersants provided optimum performance as compared to commercial standards especially, particle size distribution data while EO/PO Polyether Monoamine based on dispersant was against and then failed with the wettability and dispersion stability tests.
Practical implications
These ink formulations could be used for printing on cotton fabric by DTG technique of printing and can be used for other types of fabrics.
Originality/value
The newly prepared ink formulation for digital textile printing based on synthesized polyurethane prepolymers has the potential to be promising in this type of printing inks, to prevent clogging of nozzles on the printhead and to improve the print quality on the textile fiber.
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Hossein Motahari-Nezhad, Maryam Shekofteh and Maryam Andalib-Kondori
This study aims to investigate the characteristics, as well as the purpose and posts of the COVID-19 Facebook groups.
Abstract
Purpose
This study aims to investigate the characteristics, as well as the purpose and posts of the COVID-19 Facebook groups.
Design/methodology/approach
A systematic search for COVID-19 Facebook groups was conducted on June 1, 2020. Characteristics of the groups were examined using descriptive statistics. Mann-Whitney test was used to study the differences between groups. The study of the most popular groups’ posts was also carried out using the content analysis method.
Findings
The groups had a combined membership of 2,729,061 users. A total of 147,885 posts were received. There were about approximately 60% public groups. A high percentage of the groups (86.5%) had descriptions. The results showed a significant relationship between the groups’ description status and the number of members (p-value = 0.016). The majority of COVID-19 Facebook groups (56%) were created to meet their members’ information needs. The highest number of studied posts were related to vaccination (35.2%), followed by curfew rules (19.6%) and symptoms (10.6%).
Originality/value
Translating these insights into policies and practices will put policymakers and health-care providers in a stronger position to make better use of Facebook groups to support and enhance public knowledge about COVID-19.