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MOVPE Growth of In_xGa_(1-x)N(x～0.4) and Fabrication of Homo-junction Solar Cells

Journal of Materials Science & Technology 2013年第2期29卷 128-136页

作者： md. Rafiqul islam md. Rejvi Kaysir md. jahirul islam A. Hashimoto A. Yamamoto Department of Electrical and Electronic Engineering KUETKhulna 9203 Bangladesh Graduate School of Engineering University of Fukui 3-9-1 BunkyoFukui 910-8507 Japan

The metal organic vapor phase epitaxy （MOVPE） growth of indium gallium nitride （InGaN） has been discussed in detail towards the fabrication of solar cell. The InGaN film with In contents up to 0.4 are successfully grown by controlling the fundamental growth parameters such as the precursor gas flow rates, temperature etc. The formation of metallic In originates from the higher value （0.74） of trimethylindium/ （trimethylindium ＋ triethylgallium）（TMI/（TMI ＋ TEG）） molar ratio with low （4100） V/lll weight molar ratio while the lower value （0.2） of TMI/（TMI ＋ TEG） causes the phase separation. It is also necessary to control the growth rate and epitaxial film thickness to suppress the phase separation in the material. The crystalline quality of grown films is studied and it is found to be markedly deteriorated with increasing In content. The lattice parameters as well as the thermal expansion coefficient mismatch between GaN template and InGaN epi-layer are primarily considered as the reasons to deteriorate the film quality for higher In content. By using Ino.16Ga0.84N films, an n＋-p homo-junction structure is fabricated on 0.65 μm GaN template. For such a device, the response to the light illumination （AM 1.5） is observed with an open circuit voltage of 1.4 V and the short circuit current density of 0.25 mA/cm2. To improve the performance as well as increase solar photon capturing, the device is further fabricated on thick GaN template with higher In content. The In0.25Ga0.75N n＋-p junction solar cell is found better performance with an open circuit voltage of 1.5 V and the short circuit current density of 0.5 mA/cm2. This is the InGaN p-n homo-junction solar cell with the highest In content ever reported by MOVPE.

关键词： InGaN Metal organic vapor phase epitaxy (MOVPE) Growth Film quality Doping p-n junction

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Forest-based betel leaf and betel nut farming of the Khasia indigenous People in Bangladesh: approach to biodiversity conservation in Lawachara National Park(LNP)

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Journal of Forestry Research 2014年第2期25卷 419-427页

作者： md. jahirul islam Tapan Kumar Nath Bangladesh Planning Commission Institute of Forestry and Environmental Sciences University of Chittagong

An exploratory survey was conducted among the Khasia living in Lawachara National Parkt （LNP） to investigate their depend- ency on the protected area （PA） for livelihoods, betel leaf hill farming, traditional forest conservation and perceptions of the PA, Field data were collected by interviewing 48 household heads from two villages （punjis） located inside the LNP and visiting their farms.： The economy of the Khasia was forest-based. They were largely dependent on betel leaf hill farming in LNP and nearly 71% of their mean annual income was de- rived from this irrespective of farmer category. On average, about 14% of the incomes of the poorer farmers came from forest produce followed by 10% and 6% for medium and rich farmers respectively. Hills and forests were the foundations of their lives and livelihoods, and LNP was the life-blood of Khasia survival. As a sustainable production system, this farming practice plays a vital role in conserving biodiversity in LNP and might be replicated elsewhere.

关键词： Bangladesh indigenous people Khasia livelihoods betel leaf fanning protected area management

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Ethno-medicinal plants use by the Manipuri tribal community in Bangladesh

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Journal of Forestry Research 2010年第1期21卷 85-92,I0003,I0004页

作者： Parvez Rana Shawkat islam Sohel Sayma Akhter jahirul islam Department of Forestry and Environmental Science Shahjalal University of Science and Technology National Graduate Institute for Policy Studies

An ethno-medicinal investigation was conducted to understand the traditional knowledge of medicinal plants being used by the Maninuri tribe in Bangladesh. The present study was done through structured questionnaires in consultations with the tribal practitioners. A total 32 plant species belonging to 26 families and 29 genera were found to use for Curing 37 ailments. Results show that the use of aboveground plant parts was higher （86%） than the underground plant parts （14%）. Leaf was used in the majority of cases for medicinal preparation （17 species） followed by bark, fruit, root/rhizome, whole plant, seed and flower. Among the 32 plant species, they were mainly used to treat dysentery （10 species）, followed by fever and rheumatism （5 species each）; asthma, constipation, wounds and skin diseases （4 species each）; cold ailments, cough and diarrhea （3 species each）. The study revealed that 72% plant species investigated were used to cure more than one ailment. About 75% medicinal plants were taken orally followed by externally （9%） and both orally and externally （16%）. The study thus underscores the potentials of the ethno-botanical research and the need for the documentation of indigenous healthcare knowledge pertaining to the medicinal plant utilization for the greater benefit of mankind.

关键词： Bangladesh indigenous healthcare practice Manipur tribe medicinal plants

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Electrical Load Forecasting Using Fuzzy System

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Journal of Computer and Communications 2019年第9期7卷 27-37页

作者： Mahir Faysal md. jahirul islam md. Mohiuddin Murad md. Imd.dul islam M. Ruhul Amin Department of Electronics and Communications Engineering East West University Dhaka Bangladesh Department of Computer Science and Engineering Jahangirnagar University Savar Bangladesh Deparment of Mathematical and Physical Sciences East West University Dhaka Bangladesh

To cope with the demand and supply of electrical load of an interconnected power system of a country, we need to forecast its demand in advance. In this paper, we use a fuzzy system to forecast electrical load on short-term basis. Here, we consider temperature, humidity, seasons of a year and time segments of a day as the parameters, which govern the demand of electrical load. For each of the parameter, we use several membership functions (MFs) and then apply the Mamd.ni rule on MFs and the output is determined by using the centroid method. Finally, the surface plot reveals the real scenario of the load demand. The difference between actual load and the output of the fuzzy system is found as +1.65% to -13.76%. The concept of the paper can be applied in interconnected power system of Bangladesh to reduce power loss, especially when generation is higher than the demand.

关键词： Defuzzification Fuzzy Inference Centroid Method Surface Plot APE

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Effect of the antenna slot numbers and position on the performance of microwave ablation

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Medicine in Novel Technology and Devices 2023年第4期20卷 105-113页

作者： Sabiha Binte Aziz md.Rejvi Kaysir md.jahirul islam Torikul islam Mahmudur Rahman Department of Biomedical Engineering(BME) Khulna University of Engineering&TechnologyKhulna-9230Bangladesh Photonics Research Group Department of EEEKhulna University of Engineering&TechnologyKhulna-9230Bangladesh Department of Electrical and Computer Engineering Waterloo Institute for NanotechnologyUniversity of Waterloo200 University AveWaterlooONCanada Department of Biomedical Engineering(BME) New Jersey Institute of TechnologyNewarkNJUSA Department of Electrical and Electronic Engineering Dhaka University of Engineering&TechnologyGazipur 1707Bangladesh

Microwave ablation(MWA)is a type of thermal ablation used for cancer treatment in interventional *** induce localized tissue heating MWA employs electromagnetic waves within the microwave energy spectrum,which is done by the precisely designed *** study substantially emphasizes the design and performance ameliorating of slot(both single and double)antennae and compares the results with conventional monopole antennae in terms of temperature distribution,specific absorption ratio(SAR),and thermal tissue damage *** simulation has been done in COMSOL by solving the Bioheat equation along with Maxwell electromagnetic equations using the finite element *** simulation results reveal that the double-slot antenna has the most accurate and directional heat dissipation for liver tumors as well as the highest tissue damage rate and *** highest SAR was found to be 3500 W/kg and 3350 W/kg at the implant depth of 61 mm and 63 mm for double and single-slot antennae,*** addition,the fastest tissue damage occurred near the upper slot of the double-slot *** study helps to understand the basic design parameters for enhancing single and doubleslot antennae performance.

关键词： Microwave ablation(MWA) Finite element method(FEM) Liver tumor Microwave antenna Specific absorption rate(SAR)

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Simulation of Natural Convection Flow with Magneto-Hydrodynamics in a Wavy Top Enclosure with a Semi-Circular Heater

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Open Journal of Applied Sciences 2023年第4期13卷 591-603页

作者： Mohammad Mahfuzul islam md. Abdul Alim md. Mahmud Alam md. jahirul Haque Munshi Department of Mathematics Dhaka University of Engineering and Technology (DUET) Gazipur Bangladesh Department of Mathematics Bangladesh University of Engineering and Technology (BUET) Dhaka Bangladesh Department of Mathematics Hamdard University Bangladesh (HUB) Hamdard Nagar Gazaria Munshiganj Bangladesh

Natural convection flow in enclosure has different applications such as room ventilation, heat exchangers, the cooling system of a building etc. The Finite-Element method based on the Galerkin weighted residual approach is used to solve two-dimensional governing mass, momentum and energy-equations for natural convection flow in the presence of a magnetic field on a roof top with semi-circular heater. In the enclosure the horizontal lower wall was heated, the vertical two walls were adiabatic, inside the semi-circular heater, the wavy top wall cooled. The parameters Rayleigh number, Hartmann number and Prandtl number are considered. The effects of the Hartmann number and Rayleigh number on the streamlines, isotherms, velocity profiles and average Nusselt number are examined graphically. The local Nusselt number and the average Nusselt number of the heated portion of the enclosure with the semi-circular heater are presented in this paper. Finally, for the validation of the existing work, the current results are compared with published results and the auspicious agreement is achieved.

关键词： Natural Convection Magneto-Hydrodynamics (MHD) Finite Element Method (FEM) Wavy Enclosure Semi-Circular Heater

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Modeling of Mixed Convection in a Lid Driven Wavy Enclosure with Two Square Blocks Placed at Different Positions

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Journal of Applied Mathematics and Physics 2023年第12期11卷 3984-3999页

作者： Sree Pradip Kumer Sarker md. Mahmud Alam md. jahirul Haque Munshi Department of Mathematics Dhaka University of Engineering and Technology (DUET) Gazipur Bangladesh Department of Mathematics Hamdard University Bangladesh Munshigonj Bangladesh

The purpose of this paper is to investigate the simulation of mixed convection in a lid-driven wavy enclosure with blocks positioned at various positions. This study also examined the impact of the longitudinal position of the heated block on heat transfer enhancement. The Galerkin weighted residual finite element method is employed to computationally solve the governing equations of Navier-Stokes, thermal energy, and mass conservation. The enclosure consists of two square heated blocks strategically placed at different heights—firstly, one set is closer to the bottom surface;secondly, one set is nearer to the middle area and finally, one set is closer to the upper undulating surface of the enclosure. The wavy top wall’s thermal insulation, along with active heating of the bottom wall and blocks, generates a dynamic convective atmosphere. In addition, the left wall ascends as the right wall falls, causing the flow formed by the lid. The study investigates the impact of the Richardson number on many factors, such as streamlines, isotherms, dimensionless temperature, velocity profiles, and average Nusselt numbers. These impacts are depicted through graphical illustrations. In all instances, two counter-rotating eddies were generated within the cage. Higher rotating speed consistently leads to improved performance, irrespective of other characteristics. Furthermore, an ideal amalgamation of the regulating factors would lead to increased heat transmission.

关键词： Mixed Convection Lid-Driven Wavy Top Surface and Square Heated Blocks

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Antidiabetic Drugs in Combination with Hydroxychloroquine Improve Glycemic Control in Alloxan Induced Diabetic Rats

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Pharmacology & Pharmacy 2014年第7期5卷 725-735页

作者： Shaheda Zannah md. Saiful islam A. F. M. Towheedur Rahman md. Asaduzzaman Abdul Alim Al Bari Yusuf Ali Gazi jahirul islam A. H. M. Khurshid Alam Hazrat Ali Mamunur Rashid Department of Chemistry Khulna University of Engineering and Technology Khulna Bangladesh Department of Pharmacy University of Rajshahi Rajshahi Bangladesh

Worldwide prevalence of diabetes mellitus has become an issue of great concern in current decades. This life threatening disease is associated with worsening of glycemic control and progressive metabolic dysfunctions. Objective: Current study aimed to investigate the effect of hydroxychloroquine (HCQ) as an adjunct to glibenclamide or metformin on glycemic control in alloxan induced diabetic rats. Methods: HCQ was combined separately with two conventional anti-diabetic drugs;glibenclamide and metformin. At first, alloxan (120 mg/kg) induced diabetic rats were treated with single dose of metformin (850 mg/70 kg BW), glibenclamide (10 mg/70 kg BW) and HCQ (300 mg/70 kg BW) intraperitoneally once daily for two weeks. Then non fixed dose combinations of glibenclamide (5 mg/70 kg BW) with HCQ (150 mg/70 kg BW) and metformin (425 mg/70 kg BW) with HCQ (150 mg/70 kg BW) were injected along with those of the three drugs alone once daily for four weeks. Results: In alloxan induced diabetic rats, glibenclamide, metformin and their combination therapies reduced blood glucose level significantly but combination therapies are the most effective. Glibenclamide or metformin in combination with HCQ also significantly (P < 0.05) reduced the elevated levels of total cholesterol, triglycerides, and low density lipoprotein cholesterol (LDL-C) level and increased high density lipoprotein cholesterol (HDL-C) level. Moreover, HCQ potentiates the liver glycogen synthesis of metformin or glibenclamide. Conclusion: Outcomes of this investigation indicate that combination of glibenclamide or metformin with HCQ improves glycemic control and provides additional metabolic benefits, not achieved with either glibenclamide or metformin alone.

关键词： Diabetes Mellitus Glycemic Control HCQ Glibenclamide Metformin

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Hydrodynamic Mixed Convection in a Lid-Driven Hexagonal Cavity with Corner Heater

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American Journal of Computational Mathematics 2018年第3期8卷 245-258页

作者： M. jahirul Haque Munshi Golam Mostafa A. B. S. Manik Munsi md. Waliullah Department of Mathematics Hamdard University Bangladesh Munshiganj Bangladesh Department of Mathematics Jagannath University Dhaka Bangladesh

Hydrodynamic mixed convection in a lid-driven hexagonal cavity with corner heater is numerically simulated in this paper by employing finite element method. The working fluid is assigned as air with a Prandtl num-ber of 0.71 throughout the simulation. The left and right walls of the hex-agonal cavity are kept thermally insulated and the lid moves top to bottom at a constant speed U0. The top left and right walls of the enclosure are maintained at cold temperature Tc. The bottom right wall is considered with a corner heater whereas the bottom remaining part is adiabatic and inside the cavity a square shape heated block Th. The focus of the work is to investigate the effect of Hartmann number, Richardson number, Grashof number and Reynolds number on the fluid flow and heat transfer characteristics inside the enclosure. A set of graphical results is presented in terms of streamlines, isotherms, local Nusselt number, velocity profiles, temperature profiles and average Nusselt numbers. The results reveal that heat transfer rate increases with increasing Richardson number and Hartmann number. It is also observed that, Hartmann number is a good control parameter for heat transfer in fluid flow in hexagonal cavity.

关键词： Mixed Convection Lid-Driven Hexagonal Cavity Finite Element Method Square Block Corner Heater

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