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Article
Publication date: 20 September 2011

A.B. Mahmud Hasan, M.A. Wahab and S.M. Guo

The purpose of this paper is to present the results of analysis of the transport gases and liquid water between the gas diffusion layer (GDL) and gas flow channel (GFC) of…

Abstract

Purpose

The purpose of this paper is to present the results of analysis of the transport gases and liquid water between the gas diffusion layer (GDL) and gas flow channel (GFC) of proton exchange membrane fuel cells (PEMFCs). These results are then used to describe the effects of the GDL‐GFC interfacial conditions on the general performance of PEMFCs.

Design/methodology/approach

This analysis utilizes finite element analysis commercial codes to illustrate the transport of fluids. The gas transport data obtained from the solution are compared with the established works of others. The liquid transport processes are modeled using the Darcy equation coupled with a saturation‐capillary pressure function (the Leverett function) and assuming no phase change. In addition, the boundary conditions for the liquid transport equation are varied in order to show the extent of non‐uniformities at the GDL‐GFC interface.

Findings

Analysis shows that water dispersion from the GDL‐GFC interface extends across the GDL to its other side, and eventually reduces the performance of the PEMFC.

Research limitations/implications

It is well known that CFD simulation of fuel cells is, in general, still facing significant challenges due to the limited understanding of the complex physical and chemical processes existing within the fuel cell. The model is now under further development to improve its capabilities and undergoing further validations.

Practical implications

The simulations can provide detailed information on some of the key fluid dynamics, physical and chemical/electro‐chemical processes that exist in liquid dispersion at the interface of GDL‐GFC in fuel cells which are critical for fuel cell design and optimization.

Originality/value

The simulation can be used to understand liquid dispersion at the interface of GDL‐GFC and provide and alternative to experimental investigations in order to improve the performance of fuel cell.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 21 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 12 September 2018

Shian Li and Bengt Ake Sunden

The purpose of this paper is to investigate the thermal performance of the cooling plates with conventional straight channel and wavy channel designs.

Abstract

Purpose

The purpose of this paper is to investigate the thermal performance of the cooling plates with conventional straight channel and wavy channel designs.

Design/methodology/approach

A three-dimensional model involving coupled fluid flow and heat transfer processes is developed to study the thermal performance of the cooling plates. The effects of wavelength and amplitude on the cooling performance are also studied. In addition, two novel wavy channels with varying wavelength are proposed and investigated.

Findings

The simulated results are compared in terms of pressure drop, average temperature, maximum surface temperature, temperature difference between the maximum temperature and minimum temperature and surface temperature uniformity index. It is concluded that the cooling performance is significantly improved by the wavy channel.

Practical implications

The current study can improve the understanding of transport characterization of the cooling plates with wavy channel design and provide guidelines for the design of cooling plates.

Originality/value

The design of cooling plates with wavy channels can be used in proton exchange membrane fuel cells to improve the cooling performance.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 10 July 2019

Zhenxiao Chen, Derek Ingham, Mohammed Ismail, Lin Ma, Kevin J. Hughes and Mohamed Pourkashanian

The purpose of this paper is to investigate the effects of hydrogen humidity on the performance of air-breathing proton exchange membrane (PEM) fuel cells.

Abstract

Purpose

The purpose of this paper is to investigate the effects of hydrogen humidity on the performance of air-breathing proton exchange membrane (PEM) fuel cells.

Design/methodology/approach

An efficient mathematical model for air-breathing PEM fuel cells has been built in MATLAB. The sensitivity of the fuel cell performance to the heat transfer coefficient is investigated first. The effect of hydrogen humidity is also studied. In addition, under different hydrogen humidities, the most appropriate thickness of the gas diffusion layer (GDL) is investigated.

Findings

The heat transfer coefficient dictates the performance limiting mode of the air-breathing PEM fuel cell, the modelled air-breathing fuel cell is limited by the dry-out of the membrane at high current densities. The performance of the fuel cell is mainly influenced by the hydrogen humidity. Besides, an optimal cathode GDL and relatively thinner anode GDL are favoured to achieve a good performance of the fuel cell.

Practical implications

The current study improves the understanding of the effect of the hydrogen humidity in air-breathing fuel cells and this new model can be used to investigate different component properties in real designs.

Originality/value

The hydrogen relative humidity and the GDL thickness can be controlled to improve the performance of air-breathing fuel cells.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 March 2022

K. M. Faridul Hasan, Haona Wang, Sakil Mahmud, Ashraful Islam, Md. Ahsan Habib and Cao Genyang

Functionalization of organic cotton fabrics (OCFs) by in situ deposition of chitosan reduced-stabilized silver nanoparticles (AgNPs). No other toxic chemicals used to…

Abstract

Purpose

Functionalization of organic cotton fabrics (OCFs) by in situ deposition of chitosan reduced-stabilized silver nanoparticles (AgNPs). No other toxic chemicals used to warrant an ecofriendly synthesis protocol. Human toxicity of silver systematically avoided to use as textile clothing. Primary colors (nearly-red, yellow and blue) were imparted on OCFs via localized surface plasmon resonance (LSPR) of AgNPs. Decent mechanical properties and laundering durability in terms of antibacterial/fastness test improved mechanical properties.

Design/methodology/approach

Silver nanoparticles can be synthesized by using silver nitrate along with commercially available chitosan. Due to the surface LSPR property of silver nanoparticles, it exhibits versatile colors depending on the synthesizing procedures. The coloration occurs due to the electrostatic interaction between the AgNPs and chitosan-treated OCF. The nanotreated fabrics provide excellent mechanical properties with improved antibacterial effects.

Findings

X-ray fluorescence (XRF) analysis quantifies the developed materials in the substrates. Scanning electron microscopy (SEM) characterization indicates the appearance and morphologies of silver nanoparticles into the fabric surface after the coloration process. It proves that the treated cotton knit fabric exhibits the LSPR optical features of AgNPs. The antibacterial and mechanical properties confirm the improved functionality of products.

Originality/value

Improved mechanical properties, antibacterial performances and coloration effects on organic cotton substrates in terms of chitosan-mediated nanosilver are not yet studied.

Details

International Journal of Clothing Science and Technology, vol. 34 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 1 June 2017

Özlem Atalan and Hasan Şahan Arel

Commercial areas and bedestens (covered bazaars) are important public areas in Turkish cities and towns. These areas and buildings are essential in that they contribute…

Abstract

Commercial areas and bedestens (covered bazaars) are important public areas in Turkish cities and towns. These areas and buildings are essential in that they contribute vital economic and social characteristics to Turkish cities and towns. In the Ottoman period, these commercial areas, alongside inns, baths, mosques, and stores, were engaged in trading and manufacturing and formed a central part of life for the residents. The number of bedestens in a given city was dependent on the size of the city or town. All social, administrative, and economic activities were organized within these bedestens. Commercial structures, in which the bedestens are located, with different functions, such as arasta, inns, markets, covered markets, and stores, are the main components of the commercial districts. These structures were built by the order of the Sultan for the purpose of reviving and providing direction to the economic life of the city or town. One of the key components of these commercial structures was the bedestens. In terms of Turkish culture, a bedesten can be defined as the heart of the commercial district. Although these structures were built to sell textiles, they later functioned as places where antiques and/or valuable goods were also sold. Bedestens were usually a unique type of structure, with masonry masses between wooden stores located in the middle of the trade center of the city or town. The top of the bedesten, which was usually built as one storey and rectangular in shape, had a domed roof covered with lead. In this study, spatial analyses of these important architectural elements were conducted in terms of city planning, folk culture and commercial life. The bedestens selected for the study were those in historical cities located at major commercial road axes from the Ottoman period. The bedestens in these historical cities were examined, within the context of their planning, and assessments were made. The relations that these structures have with each other in general, and their common and different features, were also investigated.

Details

Open House International, vol. 42 no. 2
Type: Research Article
ISSN: 0168-2601

Keywords

Article
Publication date: 2 July 2018

Kazi Mahmud Hasan, S.H. Shah Newaz and Md. Shamim Ahsan

The purpose of this paper is to demonstrate the development of an aircraft-type autonomous portable drone suitable for surveillance and disaster management. The drone is…

Abstract

Purpose

The purpose of this paper is to demonstrate the development of an aircraft-type autonomous portable drone suitable for surveillance and disaster management. The drone is capable of flying at a maximum speed of 76 km/h. This portable drone comprises five distinct parts those are easily installable within several minutes and can be fit in a small portable kit. The drone consists of a ballistic recovery system, allowing the drone landing vertically. The integrated high-definition camera sends real-time video stream of desired area to the ground control station. In addition, the drone is capable of carrying ~1.8 kg of payload.

Design/methodology/approach

In order to design and develop the portable drone, the authors sub-divided the research activities in six fundamental steps: survey of the current drone technologies, design the system architecture of the drone, simulation and modeling of various modules of the drone, development of various modules of the drone and their performance analysis, integration of various modules of the drone, and real-life performance analysis and finalization.

Findings

Experimental results: the cruise speed of the drone was in the range between 45 and 62 km/h. The drone was capable of landing vertically using the ballistic recovery system attached with it. On the contrary, the drone can transmit real-time video to the ground control station and, thus, suitable for surveillance. The audio system of the drone can be used for announcement of emergency messages. The drone can carry 1.8 kg of payload and can be used during disaster management. The drone parts are installed within 10 min and fit in a small carrying box.

Practical implications

The autonomous aircraft-type portable drone has a wide range of applications including surveillance, traffic jam monitoring and disaster management.

Social implications

The cost of the cost-effective drone is within $700 and creates opportunities for the deployment in the least developed countries.

Originality/value

The autonomous aircraft-type portable drone along with the ballistic recovery system were designed and developed by the authors using their won technology.

Details

International Journal of Intelligent Unmanned Systems, vol. 6 no. 3
Type: Research Article
ISSN: 2049-6427

Keywords

Article
Publication date: 14 December 2020

Hasan Mahmud Reza, Towhid Hasan, Marjia Sultana and Md. Omar Faruque

Diabetes mellitus is becoming a growing concern worldwide. Hence, the purpose of this study is to assess the magnitude of poor glycemic control and to identify the…

Abstract

Purpose

Diabetes mellitus is becoming a growing concern worldwide. Hence, the purpose of this study is to assess the magnitude of poor glycemic control and to identify the determinants of poor glycemic control among diabetic patients attending a tertiary care hospital in Bangladesh.

Design/methodology/approach

This cross-sectional study was conducted among 732 diabetes patients seeking care at the outpatient department of Bangladesh Institute of Health Sciences Hospital, Dhaka, Bangladesh. Information, including glycemic status, was collected from patients’ medical records using a structured questionnaire.

Findings

About 87.6% of the patients were found to have poor glycemic control (glycosylated hemoglobin = 7%). Variables that were significant in bivariate analysis were put into a multivariate model where the factors associated with poor glycemic control were patients aged 41–60 years (odds ratio (OR)=2.26; 95% confidence interval (CI): 1.19–4.32, p = 0.013), suffering from diabetes for > 7 years (OR = 1.84; 95% CI: 1.12–2.99, p = 0.015), using insulin (OR = 2.34; 95% CI: 1.23–4.47; p = 0.010) or diet alone (OR = 0.20; 95% CI: 0.05–0.80, p = 0.023) as a type of diabetes treatment and proper use of medicine (OR = 0.37; 95% CI: 0.17–0.82, p = 0.015).

Originality/value

The high prevalence of poor glycemic control among diabetic patients is evident; therefore, strategic management and proper attention focusing on the predictors of poor glycemic control are necessary to reduce the long-term complications of diabetes.

Details

Nutrition & Food Science , vol. 51 no. 6
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 3 May 2022

Md. Mahiuddin Sabbir, Tahsin Tabish Khan, Amit Das, Sharmin Akter and Md. Alamgir Hossain

End-of-life electronic products exchange (EEPE) program could be an effective approach to e-waste recycling that requires consumers' participation. Thus, it is highly…

Abstract

Purpose

End-of-life electronic products exchange (EEPE) program could be an effective approach to e-waste recycling that requires consumers' participation. Thus, it is highly recommended to study factors stirring consumer behavior with regard to EEPE programs, which is largely under-explored in the existing literature. Hence, grounding on the Theory of Planned Behavior (TPB) and Attitude-Behavior-Context (A-B-C) model, this study attempts to understand the determinants of consumers' EEPE intention by adding contextual and non-cognitive factors to the proposed research model.

Design/methodology/approach

Employing a purposive sampling technique, respondents were drawn from university students and general consumers of electronic products in a developing country. Factor analysis, structural equation modeling (SEM) and SPSS PROCESS were used to analyze the collected data.

Findings

Empirical results confirm that subjective norm has the strongest positive impact on EEPE intention. Following this, attitude toward EEPE and perceived behavioral control play positive mediating roles in determining EEPE intention. Moreover, government initiatives moderate the unsolicited “attitude–intention gap”.

Practical implications

Drawing on this study's outcomes, the study urges to form comprehensive awareness-building campaigns, rules and regulations regarding proper e-waste management, promote “exchange offer” programs and educational programs to encourage EEPE.

Originality/value

This study makes two fresh contributions to the extant literature. First, by coupling the TPB and A-B-C theory, this study showed that both attitude (i.e. attitude toward EEPE) and context (i.e. government initiatives) are essential in eliciting individual-level post-consumption pro-environmental behavior (PEB) (i.e. EEPE). Second, government initiatives elucidate the attitude–intention gap in the reverse logistics context, especially in developing countries.

Details

Asia-Pacific Journal of Business Administration, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1757-4323

Keywords

Article
Publication date: 18 April 2017

Ahmed Taha Al Ajlouni

This paper aims to develop an instrument that helps in managing liquidity. Liquidity is one of the most critical issues to be considered by the financial management of the…

Abstract

Purpose

This paper aims to develop an instrument that helps in managing liquidity. Liquidity is one of the most critical issues to be considered by the financial management of the business firms to meet its financial obligations. It is more vital for banks because of the liquid nature of its assets and liabilities, along with the fact that the confidence in the bank and degree of risk depends heavily on liquidity as an indicator of its wellbeing. Islamic banks (IBs) look at the liquidity issue from the same side as the traditional banks. IBs – the most apparent Islamic financial institution – suffered from the problem of not benefiting from the lender of last resort that Central Banks (CBs) offer to traditional banks because IBs cannot borrow from the CBs at interest. The experience of Institution(s) offering Islamic Financial Services[1] (IIFS) regarding the establishment of Islamic money markets did not show a tangible success instead of the early studies done by some scholars. In spite of the rich experience of some countries in creating new money market instruments or configuration of the interest-based ones according to Islamic - Sharī’ah[2], the designs of these instruments have many limitations in terms of their tradability and flexibility, restricting their use for open-market operations by CBs.

Design/methodology/approach

The purpose of calculating the time weighted debt units (TWDUs) is to find the equivalent amount of money that the supplier can borrow to the lender in the future for a maturity that differs from the first credit contract. It is a swap between an amount of credit for a particular period of time and another amount for another period. The scheme are called traditionally as reciprocal (mutual) loans, reciprocal (mutual) deposits, swapped conditional loans and “I lend you, provided you lend me” (Hammad, 2010). It is also well known in Pakistan as time multiple counter loan (TMCL), and known within some Arabic IBs as specks (Nomar = numbers) system. This contract will be called the reciprocal loans in the current paper.

Findings

The current paper represents a blue print of suggested money market instrument (scheme) that is based on the idea of Al Qardh El Hasan (interest-free loan) – called TWDUs. This instrument does not promise any revenue for the supplier and no charge for the lender.

Research limitations/implications

The suggested model is known in traditional and contemporary writings of Islamic economists and - Sharī’ah scholars. It is accepted by many - Sharī’ah Boards in IBs (Merah, 2011) and was accepted by the Council of Islamic Ideology in Pakistan in 1980 through the TMCL. Despite that, it is still not discussed in depth by international - Sharī’ah boards as the International Islamic Fiqh Academy – in addition to the wide spread of opponent viewpoint that considers this contract as a kind of riba.

Originality/value

TWDUs is presumed to help IBs and other IIFS to add more flexibility in liquidity management in the side of risk management[3] (represented by the potential loss to IIFS arising from their inability either to meet their obligations or to fund increases in assets as they fall due without incurring unacceptable costs or losses) in addition to avoiding the case of hoarding surplus funds in the short term. Also, the suggested instrument will not be exclusive to IBs or IIFS; it can be developed to be used at a later stage by them as a mean of overdraft between IBs and their clients. Moreover, beside its viability to help in liquidity management for other firms in business sector (non-financial) or government agencies in liquidity management, TWDUs look for Islamic financial theory as an alternative to the traditional financial theory that is based on interest. Moreover, TWDUs is expected to play an important role in monetary policy in a totally Islamic financial system or even in a mixed one (Islamic and capitalistic).

Details

International Journal of Islamic and Middle Eastern Finance and Management, vol. 10 no. 1
Type: Research Article
ISSN: 1753-8394

Keywords

Article
Publication date: 26 March 2021

Mahmud Akhter Shareef, Yogesh Dwivedi, Jashim Uddin Ahmed, Uma Kumar and Rafeed Mahmud

This paper aims to address procurement, logistics management, inventory control and distribution of perishable items, i.e. vegetables, fruits, flowers and fishes, during…

Abstract

Purpose

This paper aims to address procurement, logistics management, inventory control and distribution of perishable items, i.e. vegetables, fruits, flowers and fishes, during the social isolation period of the Covid-19 era to identify conflicting interests among the channel members; present inventory and information sharing scenario; and reveal organizational dispute and existence of redundant, nonessential and corrupted members in the supply chain.

Design/methodology/approach

This study uses an exploratory investigation to evaluate the relations among the members of the supply chain of perishable food items. In this context, it is designed to investigate the field, observe the members of the existing supply chain from rural and remote places and capture their interviews to accomplish the objectives.

Findings

This study identified that although the supply chain of perishable food items is controlled truly by private parties, from a realistic view, the private–public partnership is essential where the government should play the coordinating role. In this context, continuous interaction, coordination and information sharing among the members to establish an optimum and scalable network and remove any redundant nodal points is a key success factor for managing an efficient supply chain.

Research limitations/implications

Theoretical and managerial implication of this research is enormous. The existence of functional and dysfunctional conflicts in the same supply network and how it can be detrimental to the performance of the members are exposed in this study, which can be an excellent source to be investigated. Practitioners and researchers can gain a greater understanding to identify the root causes of conflicts in the existing structural dynamics, shedding light on organizational interactions, power and group behavior during the Covid-19 era.

Originality/value

From the light of management and inter-organizational conflicts, this is a pioneer study that has detected the redundant channel members, their source of power and how their removal can present an optimum channel with group coherence and synergistic interest.

Details

The International Journal of Logistics Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0957-4093

Keywords

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