Ahsanullah University of Science and Technology

Dhaka, Bangladesh

Ahsanullah University of Science and Technology is a Private Technical University located in Dhaka, Bangladesh. This is one of the leading private universities in Bangladesh. The University was founded by the Dhaka Ahsania Mission in 1995. Dhaka Ahsania Mission is a non-profit voluntary organization in Bangladesh. The Mission was established in 1958 by Khan Bahadur Ahsanullah.It maintains close collaboration with the International Association of Universities , University Grants Commission , Bangladesh and many other National and International Education Institutions and Professional bodies. Ranking:World rank 9215. Wikipedia.

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Saeed T.,Ahsanullah University of Science and Technology | Sun G.,James Cook University
Bioresource Technology | Year: 2013

This paper reports the pollutant removal efficiencies of two lab-scale hybrid wetland systems treating a textile wastewater. The two systems had identical configurations, each consisting of a vertical flow (VF) and a horizontal flow (HF) wetland that were filled with organic sugarcane bagasse and sylhet sand as the main media. The systems were operated under high hydraulic loading (HL) (566-5660mm/d), and inorganic nitrogen (254-508gN/m2d) and organics loadings (9840-19680g COD/m2d and 2154-4307g BOD5/m2d). Simultaneous removals of BOD5 (74-79%) and ammonia (59-66%) were obtained in the first stage VF wetlands, demonstrating the efficiency of the media for oxygen transfer to cope with the high pollutant loads. The organic carbon (C) content of sugarcane bagasse facilitated denitrification in the VF wetlands. Second stage HF wetlands provided efficient color removal under predominantly anaerobic condition. Overall, the wetland systems showed stable removal performances under high, and unsteady, pollutant loadings. © 2012 Elsevier Ltd.

Saeed T.,Ahsanullah University of Science and Technology | Afrin R.,Ahsanullah University of Science and Technology | Muyeed A.A.,Ahsanullah University of Science and Technology | Sun G.,James Cook University
Chemosphere | Year: 2012

This paper reports the pollutant removal performances of a hybrid wetland system in Bangladesh for the treatment of a tannery wastewater. The system consisted of three treatment stages: a subsurface vertical flow (VF) wetland, followed by a horizontal flow (HF) and a VF wetland. The wetlands were planted with common reed (Phragmites australis), but employed different media, including organic coco-peat, cupola slag and pea gravel. In the first stage, experimental results demonstrated significant removal of ammonia (52%), nitrate (54%), BOD (78%), and COD (56%) under high organics loading rate (690gCODm-2d-1); simultaneous nitrification, denitrification, and organics degradation were attributed to the unique characteristics of the coco-peat media, which allowed greater atmospheric oxygen transfer for nitrification and organic degradation, and supply of organic carbon for denitrification. The second stage HF wetland produced an average PO4 removal of 61%, primarily due to adsorption by the iron-rich cupola slag media. In the third treatment stage, which was filled with gravel media, further BOD removal (78%) from the tannery wastewater depleted organic carbon, causing the accumulation of NO3 in the wastewater. Overall, the average percentage removals of NH3-N, NO3-N, BOD, COD, and PO4 were 86%, 50%, 98%, 98% and 87%, respectively, across the whole hybrid system. The results provided a strong evidence to support widespread research and application of the constructed wetland as a low-cost, energy-efficient, wastewater treatment technology in Bangladesh. © 2012 Elsevier Ltd.

Islam M.T.,Ahsanullah University of Science and Technology
Clean Technologies and Environmental Policy | Year: 2016

An attempt has been taken to reformulate the dyeing process of cotton fabric with the aim of reducing the environmental pollution with economic advantages by the substitution of harmful chemical auxiliaries with ethanol at low concentration. The results were studied in comparison with the standard conventional recipe, and a favorable effect of alcohol addition, at 1-3 g/L, on the dye uptake, equilibrium time of isothermal dyeing was achieved in laboratory scale. Fastness properties and dyeing levelness were also compared. Color fastness to wash and rubbing were found to be unaffected with better levelness of dyeing by the introduction of ethanol in the reactive dyeing recipe of cotton. Ethanol replaced dyeing auxiliaries successfully by serving the function of both wetting and leveling agent where it is readily biodegradable, and hence, this process becomes eco-friendly. Finally, environmental and economic issues arising from chemical substitution of dyeing additives with ethanol were considered, and environmental advantages and cost saving due to the application of ethanol in comparison with dyeing auxiliaries were brought to light. © 2015 Springer-Verlag Berlin Heidelberg.

Hossain M.S.,Ahsanullah University of Science and Technology | Alim M.A.,Bangladesh University of Engineering and Technology
International Journal of Heat and Mass Transfer | Year: 2014

The paper is connected to investigate numerical simulation of two-dimensional laminar steady-state on MHD free convection within trapezoidal cavity with non-uniformly heated bottom wall. The cavity consists of non-uniformly heated bottom wall, insulated top wall and isothermal side walls with inclination angles. Heat flow patterns in the presence of free convection within trapezoidal enclosures have been analyzed with heatlines concept. The fluid is concerned for the wide range of Rayleigh number (Ra) from 10 3 to 107 and Prandtl number (Pr) from 0.026, 0.7, 1000 with various tilt angles Φ = 45, 30 and 0 (square). The physical problems are represented by non-dimensional governing equations along with the corresponding boundary conditions and discretized by using Galerkin weighted residual method of finite element formulation. Results are presented in terms of streamlines, isotherms, local Nusselt number along distance and average Nusselt number along Rayleigh number, Ra for non-uniform heating of the bottom wall, governing parameters namely, Prandtl number Pr, and at the three values of Rayleigh number Ra, varying from 103 to 107, covering free convection dominated regimes. It is shown that the average and local Nusselt number at the non-uniform heating of bottom wall of the cavity is depending on the dimensionless parameters and also tilts angles. © 2013 Published by Elsevier Ltd. All rights reserved.

Rhaman M.M.,Ahsanullah University of Science and Technology
International Journal of Renewable Energy Research | Year: 2013

Bangladesh is the 7th largest population (164.4 Million) and 12th density of population (1034/km2) country in the world. Bangladesh is one of the most electric deprived countries. Electric energy protection is performed of decreasing the quantity of energy used in day by day. Bangladesh is a developing country, so their demand of electricity increases tremendously. Energy preservation is the result of financial capital increase of the country and also increases the environmental values. In Bangladesh maximum electric energy generated by Fossil Fuel, Gas, Coal, which is created air and water pollution and also negative impact on global calamity. That's why the peoples are focus on renewable energy generation system. Non renewable energy source like Fuel, Gas, Coal are limited and it is important to reserve this sources for our future generation. There is large prospective for renewable energy source in Bangladesh, currently their contribution to the electric supply remaining insignificant compare to our total supply (1% only). The main objective of this research paper is to develop an alternative energy generation technique such as "Hybrid Renewable Energy System (HRES)" for sustainable future. When HRES is used in remote area, diesel generator will be coupled with the system for reliability. In this paper, I analyzed 'Wind + Diesel-Generator + Battery', 'Photovoltaic (PV) + Diesel-Generator + Battery' and 'Wind + Photovoltaic (PV) + Diesel-Generator + Battery' HRES is very much essential and useful for rural and isolated Island areas of Bangladesh.

Rahman M.Z.,Ahsanullah University of Science and Technology
Renewable and Sustainable Energy Reviews | Year: 2014

This paper discussed advances in several suitable passivation schemes and emitter optimization techniques available up to date. c-Si endowed with numerous crystal defects and impurities which are responsible for lower efficiency of solar cells made out of it. The surface passivations and emitter formations are the two inevitable processes to upgrade the solar cells efficiency by circumventing several induced effects due to associated crystal defects and impurities of c-Si. This work will act as a common place for the solar cell researchers, engineers and for the students to get the very recent results of surface passivation and emitter optimization techniques practiced both in the industries and R&D laboratories over the world. Key issues here to be considered while agglomerating the relevant information for each process step are the cost-effectiveness, added complexity, additional benefits, reliability, and efficiency potential. © 2013 Elsevier Ltd.

Rahman M.Z.,Ahsanullah University of Science and Technology
Renewable and Sustainable Energy Reviews | Year: 2012

The aims of this paper are to demonstrate a critical review of the multitude of progress in solar PV research and applications in Bangladesh since its inception in 1996 till 2010. Our studies show that Bangladesh has been experiencing an accelerated shift towards solar PV to meet the gap between demand and supply of electricity along with conventional electricity generation. Despite the present generation of electricity from solar PV is 15-20 MW, both public and private sectors have started several solar PV projects to generate several hundred of MW by the upcoming years. This paper has also tried to identify the critical barriers for widespread dissemination of solar PV in Bangladesh and has discussed possible ways to overcome those barriers as well. © 2011 Elsevier Ltd. All rights reserved.

Rahman M.Z.,Ahsanullah University of Science and Technology
International Journal of Renewable Energy Research | Year: 2012

This paper presents the qualitative analysis of the variation of effective lifetime of minority carriers in p-type Si solar cell due to different recombination mechanisms associated with it. There is a direct relation between the minority carrier lifetime and the solar cell efficiency. The higher lifetime of minority carrier results in increased conversion efficiency of silicon solar cell. As silicon wafers are endowed with different crystal defects and grain boundaries, a reduced minority carrier lifetime is observed for both bulk and surface recombination processes that occur through these defects. A detailed knowledge of the role of recombination processes on carrier lifetime will facilitate the design of high efficiency solar cell.

Baki A.K.M.,Ahsanullah University of Science and Technology
IEEE Transactions on Smart Grid | Year: 2014

Data refreshment rate of a present power system is relatively slow and in some cases this slow refreshment rate may not be capable of providing information about dynamic state of power system devices. The use of multi protocol label switching based technique is one option to overcome this problem. A cost effective and simpler detection device is needed for condition monitoring and integrating the sensor signals into the smart grid monitoring system. Remote and on-line monitoring of ultra wide band partial discharge signal in a switch-yard is a new concept in smart grid technology that will help avoid damage of switchyard devices. It is possible to convert the radio frequency partial discharge signal into an equivalent milli-volt or milli-ampere output for remote or centralized monitoring of switchyard devices. Multi Protocol Label Switching based data transfer rate is faster than the conventional data transfer system of a power grid. In this paper a new and technically better method of on-line radio frequency partial discharge monitoring from a remote smart grid control room through multi protocol label switching is discussed. © 2010-2012 IEEE.

Khan M.H.R.,Ahsanullah University of Science and Technology | Hossain A.K.M.A.,Bangladesh University of Engineering and Technology
Journal of Magnetism and Magnetic Materials | Year: 2012

A series of polycrystalline ferrites having nominal chemical composition Co0.50-xMnxZn0.5Fe2O4 (0

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