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A monodisperse-aerosol generation system： Design, fabrication and performance

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Particuology 2017年第5期15卷 118-125页

作者： Amit md. Estiaque arefin M.H. Masud Mohammad U.H. Joardder md. Shamim Akhter Department of Mechanical Engineering Rajshahi University of Engineering and Technology Rajshahi Bangladesh

Monodisperse aerosols are essential in many applications, such as filter testing, aerosol instrument calibration, and experiments for validating models. This paper describes the design principle, construction, and performance of a monodisperse-aerosol generation system that comprises an atomizer, virtual impactor, microcontroller-based isokinetic probe, wind tunnel, and velocity measurement device. The size distribution of the produced monodisperse aerosols was determined by an optical particle counter. The effects of atomizer characteristics, the rates of minor and major flow, and solution criteria were investigated. It was found that all these parameters affect the generation of monodisperse aerosol. Finally, the expected geometric standard deviation （〈1.25） of monodisperse aerosol particles was obtained with the most suitable atomizer for 10% oleic acid in ethyl alcohol solution with 5%-15% minor flow, where the ratio between the nozzle-to-probe distance and acceleration-nozzle-exit diameter was 0.66. The con- structed monodisperse-aerosol-generation system can be used for instrumental calibration and aerosol research.

关键词： Aerosol generation Monodisperse Design Sampling Counting

Performance analysis of a novel integrated photovoltaic-thermal system by top-surface forced circulation of water

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Clean Energy 2020年第4期4卷 316-327页

作者： md.Arman arefin Mohammad Towhidul Islam Mohammad Zunaed Khodadad Mostakim Department of Mechanical Engineering Rajshahi University of Engineering&TechnologyRajshahi-6204Bangladesh

Almost 80-90%of energy is wasted as heat(provides no value)in a photovoltaic(PV)*** integrated photovoltaic-thermal(PVT)system can utilize this energy and produce electricity *** this research,through energy and exergy analysis,a novel design and methodology of a PVT system are studied and *** the common methods,here the collector is located outside the PV panel and connected with *** passes over the top of the panel and then is forced to the collector by a *** effects of different water-mass flow rates on the PV panel and collector,individual and overall efficiency,mass loss,exergetic efficiency are examined *** show that the overall efficiency of the system is around five times higher than the individual PV-panel *** forced circulation of water dropped the panel temperature and increased the panel efficiency by 0.8-1%and exergy by 0.6-1%,where the overall energy efficiency was~81%.

关键词： integrated photovoltaic-thermal forced cooling energy analysis exergy analysis flat-plate collector

A Numerical Simulation of Air Flow in the Human Respiratory System Based on Lung Model

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Journal of Applied Mathematics and Physics 2023年第8期11卷 2205-2215页

作者： md. Kamrul Hasan Mahtab U. Ahmmed md. Samsul arefin Department of Mathematics Khulna University of Engineering and Technology Khulna Bangladesh Department of Mathematics Jahangirnagar University Dhaka Bangladesh

The lung is an important organ that takes part in the gas exchange process. In the study of gas transport and exchange in the human respiratory system, the complicated process of advection and diffusion (AD) in airways of human lungs is considered. The basis of a lumped parameter model or a transport equation is modeled during the inspiration process, when oxygen enters into the human lung channel. The quantitative measurements of oxygen are detached and the model equation is solved numerically by explicit finite difference schemes. Numerical simulations were made for natural breathing conditions or normal breathing conditions. The respiratory flow results for the resting conditions are found strongly dependent on the AD effect with some contribution of the unsteadiness effect. The contour of the flow rate region is labeled and AD effects are compared with the variation of small intervals of time for a constant velocity when breathing is interrupted for a negligible moment.

关键词： Lumped Model Lumped Model Channel Mass Flow Rate Ideal Law of Gas 2D Advection Diffusion Equation Finite Difference Scheme

Time delay of the appearance of a new strain can affect vaccination behavior and disease dynamics:An evolutionary explanation

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Infectious Disease Modelling 2023年第3期8卷 656-671页

作者： md.Mamun-Ur-Rashid Khan md.Rajib arefin Jun Tanimoto Interdisciplinary Graduate School of Engineering Sciences Kyushu UniversityKasuga-koenKasuga-shiFukuoka816-8580Japan Faculty of Engineering Sciences Kyushu UniversityKasuga-koenKasuga-shiFukuoka816-8580Japan Department of Mathematics University of DhakaDhaka1000Bangladesh

The emergence of a novel strain during a pandemic,like the current COVID-19,is a major concern to the healthcare *** most effective strategy to control this type of pandemic is *** previous studies suggest that the existing vaccine may not be fully effective against the new ***,the new strain's late arrival has a significant impact on the disease dynamics and vaccine *** on these issues,this study presents a two-strain epidemic model in which the new strain appears with a time *** considered two vaccination provisions,namely preinfection and post-infection vaccinations,which are governed by human behavioral *** such a framework,individuals have the option to commit vaccination before being infected with the first ***,people who forgo vaccination and become infected with the first train have the chance to be vaccinated(after recovery)in an attempt to avoid infection from the second ***,a second strain can infect vaccinated and unvaccinated *** may have additional opportunities to be vaccinated and to protect themselves from the second strain due to the time *** the cost of the vaccine,the severity of the new strain,and the vaccine's effectiveness,our results indicated that delaying the second strain decreases the peak size of the infected ***,by estimating the social efficiency deficit,we discovered that the social dilemma for receiving immunization decreases with the delay in the arrival of the second strain.

关键词： Vaccination Behavior dynamics Two-strain epidemic Time delay Social efficiency deficit

Modified EDMONDS-KARP Algorithm to Solve Maximum Flow Problems

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Open Journal of Applied Sciences 2016年第2期6卷 131-140页

作者： Kalyan Kumar Mallick Aminur Rahman Khan Mollah Mesbahuddin Ahmed md. Shamsul arefin md. Sharif Uddin Department of Mathematics University of Development Alternative (UODA) Dhaka Bangladesh Department of Mathematics Jahangirnagar University Savar Dhaka Bangladesh Department of Computer Science and Engineering University of Development Alternative (UODA) Dhaka Bangladesh

Maximum Flow Problem (MFP) discusses the maximum amount of flow that can be sent from the source to sink. Edmonds-Karp algorithm is the modified version of Ford-Fulkerson algorithm to solve the MFP. This paper presents some modifications of Edmonds-Karp algorithm for solving MFP. Solution of MFP has also been illustrated by using the proposed algorithm to justify the usefulness of proposed method.

关键词： Maximum Flow Maximum Flow Problem Breadth First Search Augmenting Path Residual Network

Analytical behavior of weakly dispersive surface and internal waves in the ocean

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Journal of Ocean Engineering and Science 2022年第4期7卷 305-312页

作者： Mohammad Asif arefin md.Abu Saeed M.Ali Akbar M.Hafiz Uddin Department of Mathematics Jashore University of Science and TechnologyJashore7408Bangladesh Department of Applied Mathematics University of RajshahiRajshahi6205Bangladesh

The(2+1)-dimensional interaction of a Riemann wave propagating along the y-axis with a long wave along the x-axis is described by the space-time fractional Calogero-Degasperis(CD)and fractional poten-tial Kadomstev-Petviashvili(PKP)*** can be modeled according to the Hamiltonian structure,the lax pair with the non-isospectral problem,and the pain level *** proposed equations are widely used in beachfront ocean and coastal engineering to describe the propagation of shallow-water waves,demonstrate the propagation of waves in dissipative and nonlinear media,and reveal the propagation of waves in dissipative and nonlinear *** this paper,we have established further exact solutions to the nonlinear fractional partial differential equation(NLFPDEs),namely the space-time fractional CD and fractional PKP equations using the modified Rieman-Liouville fractional derivative of Jumarie through the two variable(G/G,1/G)-expansion *** far as trigonometric,hyperbolic,and rational function so-lutions containing parameters are concerned,solutions are acquired when unique characteristics are as-signed to the ***,the solitary wave solutions are generated from the solutions of the traveling *** is important to observe that this method is a realistic,convenient,well-organized,and ground-breaking strategy for solving various types of NLFPDEs.

关键词： Two variable(G/G,1/G)-expansion method Exact solution Traveling wave solutions Solitary wave solutions The space-time fractional CD equation The space-time fractional PKP equation

Competitiveness of Winter Rice Varieties against Weed under Dry Direct Seeded Conditions

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Agricultural Sciences 2017年第12期8卷 1415-1438页

作者： A. N. M. Atikur Rahman A. K. M. Mominul Islam md. Altamas arefin md. Rashedur Rahman md. Parvez Anwar Weed Management Laboratory Department of Agronomy Bangladesh Agricultural University Mymensingh Bangladesh Department of Agronomy Bangladesh Agricultural University Mymensingh Bangladesh

Aerobic rice or dry direct seeded rice is highly vulnerable to weeds because of lack of “head start” over weeds and standing water layer to suppress weeds. The risks of chemical control and the huge cost involvement in mechanical control demand an eco-friendly and cost-effective integrated weed management. Weed competitive rice cultivar may be considered as a viable tool for integrated weed management. In these circumstances, an experiment was designed to evaluate weed competitiveness of some selected winter rice varieties under aerobic soil conditions. The study was conducted during dry season (February to June) 2016 at the Agronomy Field Laboratory and Weed Management Laboratory, Bangladesh Agricultural University, Mymensingh. Fourteen rice varieties namely, BRRI dhan28, BRRI dhan29, BRRI dhan47, BRRI dhan50, BRRI dhan55, BRRI dhan58, BRRI dhan59, BRRI dhan67, Binadhan-5, Binadhan-6, Binadhan-8, Binadhan-10, BRRI hybrid dhan3 and Agrodhan-14 were grown under weedy and weed-free conditions. Plots with no rice were also maintained to observe the natural growth of weed in absence of rice. The experiment was conducted with split-plot design with three replications. Weeding regime was allocated in main plot and rice variety was allocated in sub-plot. Results showed that rice varieties varied widely in their yield performances and weed competitiveness. Among rice varieties, BRRI dhan59 allowed the minimum weed growth (19.2 g m-2) while Binadhan-5 allowed the maximum weed growth (62.8 g m-2). Grain yield ranged from 1.85 t ha-1 (BRRI dhan55) to 3.92 t ha-1 (Binadhan-5) under weed-free condition and between 0.41 t ha-1 (BRRI dhan55) and 2.06 t ha-1 (BRRI dhan59) under weedy condition. Weed inflicted relative yield loss ranged from 43.4% to 82.1% among the varieties. BRRI dhan59 allowed the least yield penalty (43.4%) while Binadhan-5 had the maximum yield penalty (82.1%) due to weed competition. Although Binadhan-5 is the most productive variety (3.92 t ha-1) for aerobic

关键词： Aerobic Rice Rice-Weed Competition Dryland Farming Weed Pressure Weed Management

Wireless Body Area Network: An Overview and Various Applications

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Journal of Computer and Communications 2017年第7期5卷 53-64页

作者： md. Taslim arefin Mohammad Hanif Ali A. K. M. Fazlul Haque Department of Computer Science and Engineering Jahangirnagar University Dhaka Bangladesh Department of Electronics and Telecommunication Engineering Daffodil International University Dhaka Bangladesh

Over the past years a booming interest is comprehended in the field of wireless communication for the development of a monitoring system to observe human vital organs activities remotely. Wireless Body Area Network (WBAN) is such network that provides a continuous monitoring over or inside human body for a long period and can support transmission of real time traffic such as data, voice, video to observe the status of vital organs functionalities. In this paper an overview of WBAN technology and its requirements has been narrated. The aim of this paper was to offer a suitable and appropriate wireless technology for deploying WBAN. Several suitable short range wireless communication technologies that can be adopted in WBAN have also been discussed. Finally numerous applications in the field of medical and non-medical sectors using WBAN technology have been outlined.

关键词： WBAN WiFi Bluetooth ZigBee Monitoring Sensors WBAN Applications

Integrated Nutrient Management Improves Productivity and Quality of Sugarcane(Saccharum Officinarum L.)

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Phyton-International Journal of Experimental Botany 2022年第2期91卷 439-469页

作者： md.Shamsul arefin md.Ariful Islam md.Mokhlesur Rahman md.Abdul Alim Sabry Hassan Mahmoud F.K.Soliman Mohamed M.Hassan Rajan Bhatt Akbar Hossain Physiology and Sugar Chemistry Division Bangladesh Sugarcrop Research InstituteIshurdi6620Bangladesh On-Farm Research Division Bangladesh Agricultural Research InstitutePabna6600Bangladesh Department of Agricultural Chemistry Bangladesh Agricultural UniversityMymensingh2202Bangladesh Department of Food Technology and Rural Industries Bangladesh Agricultural UniversityMymensingh2202Bangladesh Department of Biology College of ScienceTaif UniversityTaif21944Saudi Arabia Nature Conservation Sector Egyptian Environmental Affairs AgencyCairo11728Egypt Regional Research Station Panjab Agricultural UniversityKapurthala144601India Bangladesh Wheat and Maize Research Institute Dinajpur5200Bangladesh

Sugarcane is one of the major important sugar yielding crops in *** an exhaustive crop,sugarcane removes a huge amount of plant nutrients from the ***,the combined use of organic and inorganic fertilizers can be a good approach to deal with nutrient depletion and promote sustainable crop production as well as improve soil ***,an attempt was made to identify the most fruitful and profitable integrated nutrient management on the aspects of growth,yield and quality of sugarcane in two consecutive growing *** treatments:T_(1)=Control,T_(2)=165:55:120:30:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(3)=Poultry Litter(PL)at 5 t ha^(−1)+95:51:87:9:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(4)=Cow Dung(CD)at 15 t ha^(−1)+36:52:60:17:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(5)=Press Mud(PM)at 15 t ha^(−1)+10:50:43:0:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(6)=Mustard Oil Cake(MOC)at 0.5 t ha^(−1)+140:54:115:25:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1)and T_(7)=GM(Green Manure)at 5 t ha^(−1)+140:53:100:28:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1)were used in this *** years data showed that treatment T_(3)produced the maximum amount of tillers,total dry matter yield,millable sugarcane,cane yield and sugar yield,followed by the T_(4)*** highest stalk heights were recorded in the T_(3)treatment,which was statistically similar to all other treatments except T_(1)and T_(2).The juice quality parameters viz.,brix and pol in cane were found significant in treatment T_(3)while the highest purity was obtained in the T_(7)*** the data of Jaggery(goor)quality parameters,the highest sucrose content,color transmittance,Jaggery(goor)recovery and the lowest ash content of Jaggery(goor)were observed in the T_(3)treatment,which was statistically similar to the T_(4)treatment in both *** highest cost of production was obtained from the T_(6)treatment while the highest gross return,net return and BCR were recorded in the T_(3)*** sig

关键词： Nutrient fertilizer growth physiology yield quality sugarcane