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A New Algorithm for a Condenser Design for Large-Scale Nuclear Power Plants in Tropical Region

Journal of Thermal Science 2020年第5期29卷 1370-1389页

作者： khan Abid Hossain islam md.shafiqul Department of Industrial and Production Engineering Jashore University of Science and TechnologyJashore 7408Bangladesh Department of Nuclear Engineering University of DhakaDhaka 1000Bangladesh

This work presents a new velocity search algorithm for designing a condenser of a 1200 MWe large-scale nuclear power plant situated in tropical *** this,the condenser pressure was considered in the range of 7.5-15 kPa while its tube inner diameter was taken as 28 mm with 1 mm tube wall *** longitudinal and transverse condensers with multiple shell tanks and varied shell tank lengths from 8-14 m have been considered in this *** different tertiary coolant temperature rises were chosen as 4°C,8°C and 12°C by considering tropical region average reservoir water temperature range of 28°C to 32°C during *** of tertiary coolant was kept within 0.75-1.5 m/s to ensure sufficient turbulence to avoid erosion-corrosion of the *** simulation has been employed to obtain tube-side pressure drop and convection heat transfer coefficient directly from tertiary coolant inlet velocity using κ-ω turbulent flow model.A new iterative“Velocity-search algorithm”has been developed that focuses on finding the correct tertiary coolant velocity instead of overall heat transfer *** revealed that velocity-search algorithm yielded very close to the important physical and thermal parameters of condenser compared to the existing design data in large scale nuclear power ***-search algorithm has given less number of condenser design physical parameters that meets the velocity acceptance criteria for longitudinal condenser compared to the transverse ***,velocity-search algorithm is found to be more reliable,robust,and consistent for condenser design compared to the conventional design algorithm used in Log-Mean Temperature Difference method.

关键词： nuclear power plant vacuum condenser velocity-search algorithm tropical region

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Prediction of Turbulent Flow Structure in a Fully Developed Rib-Roughened Narrow Rectangular Channel

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Journal of Thermal Science 2009年第2期18卷 126-136页

作者： md.shafiqul islam M.Kaminaga R.Hino M.Monde Atomic Energy Research Establishment Japan Atomic Energy Agency (JAEA) Department of Mechanical Engineering Saga University

Fully developed turbulent water-flow structure over one-side repeated-ribs in narrow two-dimensional rectangular channels was investigated experimentally by Particle Image Velocimetry （PIV） and analytically by the standard k-ε and nonlinear k-ε turbulent models. Two rib-pitch to height ratios （p/k） of 10 and 20 were investigated while the rib height was held constant at 4 mm. The rib height-to-channel equivalent diameter ratio （k/De） was 0.1. The streamwise mean velocity and turbulent kinetic energy distributions at six selected axial stations from the center rib for the two Reynolds number （Re） of 7,000 and 20,000 were obtained and compared with the predicted one. The performance ability in predicting separating and reattaching turbulent water-flow between the standard K-ε and nonlinear k-ε models had yielded no clear conclusion. A large-scale turbulent eddy was generated by the rib promoter and then propagated into the mainstream flow, which led to the deformation of the velocity profile. The turbulent kinetic energy was increased about two times higher at p/k = 20 than that at p/k =10 under the two Reynolds numbers. The effect of the p/k value and the Reynolds number （Re） on reattachment length （XR） was investigated and showed that the p/k and Re had no significant effect on the reattachment length beyond a critical value of Re = 15,000 where XR was found to be approximately 4 times of the rib height under water-flow condition.

关键词： Turbulent water-flow structure repeated-ribs narrow rectangular channels two-dimensional analysis reattachment length

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Annual pattern of zooplankton communities and their environmental response in a subtropical maritime channel system in the northern Bay of Bengal, Bangladesh

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Acta Oceanologica Sinica 2018年第8期37卷 65-73页

作者： ABDULLAH Al Mamun ALAM md.Didarul AKHTAR Aysha XU Henglong islam md.shafiqul MUSTAFA KAMAL Abu Hena UDDIN M Muslem ALAM md.Wahidul Laboratory of Microbial Ecology Ocean University of China Faculty of Marine Sciences and Fisheries University of Chittagong Department of Animal Science and Fishery Faculty of Agriculture and Food Sciences Universiti Putra Malaysia Campus Bintulu

Zooplankton plays an important role in aquatic food webs by fluxing of energy from primary producer to subsequent trophic levels in the food chain. The annual pattern of zooplankton communities and potential environmental drivers were studied in the Kohelia channel, Bangladesh from summer 2014 to spring *** were collected using net at a depth of 1 m. A total of 32 species belonged to 18 orders, 27 families and 15 taxonomic groups were identified. Of these species, 22 distributed in all four seasons of which 8 were dominant and highly contributing to the total communities. Species number peaked in summer next to winter and fall in spring while maximum abundance was in summer and minimum in spring. Multivariate analyses showed that there was a clear annual pattern in the zooplankton communities. Species diversity and evenness peaked in spring but fall in autumn while the high value of species richness was found in winter. Biological-environmental best matching（BIO-ENV） analyses conformed that community pattern of zooplankton was mainly driven by transparency salinity, and temperature individually or combined with water nutrients. These results demonstrate that annual pattern of the zooplankton community shaped by channel environmental factors in subtropical channel ecosystems, thus might be used for community-based subtropical coastal water bioassessment.

关键词： zooplankton trophic levels subtropical channel community structure multivariate approach

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Watering techniques and zero-valent iron biochar pH effects on As and Cd concentrations in rice rhizosphere soils,tissues and yield

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Journal of Environmental Sciences 2021年第2期33卷 144-157页

作者： md.shafiqul islam Yali Chen Liping Weng Jie Ma Zulqarnain Haider khan Zhongbin Liao Abdoul Salam Issiaka Abdoul Magid Yongtao Li Agro-Environmental Protection Institute/Key Laboratory for Environmental Factors Control of Agro Product Quality Safety Ministry of Agriculture and Rural AffairsTianjin 300191China College of Natural Resources and Environment South China Agricultural UniversityGuangzhou 510642China Chinese Academy of Agricutural Sciences Beijing 100081China Department of Soil Quality Wageningen Universit6700 AAWageningenNetherlands

Zero-valent iron amended biochar(ZVIB)has been proposed as a promising material in immobilizing heavy metals in paddy *** this study,the impacts of p H of ZVIB(p H 6.3 and p H 9.7)and watering management techniques(watering amount in the order of CON(control,5/72)>3/72>1-3/72>3/100>1/72,with 5/72,for example,representing irrigation given to 5 cm above soil surface in 72 hr regular interval)on As and Cd bioavailability for rice and its grain yield(Yield BR)were investigated in a pot *** rice As(As BR)content was irrelative to the watering treatments,while significantly decreased(>50%)with the addition of both ZVIB *** diminutions of brown rice Cd(Cd BR)content as well as the Yield BR were highly dependent on both the soil amendment materials’p H and watering *** all the watering treatments,3/72 treatment(15%less irrigation water than the CON)with ZVIB 6.3 amendment was the optimum fit for simultaneous reduction of As BR(50%)and Cd BR contents(19%)as well as for significant increment(12%)of the Yield *** high pH(9.7)ZVIB application could also efficiently decrease As and Cd contents in brown rice,it might risk grain yield lost if appropriate(e.g.3/72 in our study)watering management technique was not ***,ZVIB would be an environmentally friendly option as an amendment material with proper selection of watering management technique to utilize As and Cd co-contaminated arable soils safely for paddy cultivation.

关键词： Brown rice As Brown rice Cd Grain yield Paddy soils Water management Zero-valent iron biochar

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Source identification, contamination status and health risk assessment of heavy metals from road dusts in Dhaka, Bangladesh

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Journal of Environmental Sciences 2022年第11期34卷 159-174页

作者： Aklima Nargis Ahsan Habib md Nazrul islam Kai Chen md.shafiqul islam Sarker A N M Al-Razee Wenbin Liu Guorui Liu Minggang Cai Coastal and Ocean Management Institute&State Key laboratory of Marine Environmental Science Xiamen UniversityXiamen 361005China Department of Chemistry University of DhakaDhaka 1000Bangladesh Central Chemical Laboratory Department of Narcotics ControlMinistry of Home AffairsDhaka 1204Bangladesh Department of Analytical Chemistry&Environmental Science Training Institute for Chemical IndustriesPolashNarsingdi 1611Bangladesh State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

In this study, concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined in road dusts collected from different locations in Dhaka to assess source, contamination status and health risk. Energy-dispersive X-ray fluorescence spectroscopy and energy-dispersive X-ray spectroscopy were used to determine Cr, Mn, Ni, Cu, Zn, Cd and Pb and their mean concentrations were 162.27 ± 29.46, 721.18 ± 180.14, 35.65 ± 12.55, 104.56 ± 128.33, 515.32 ± 321.90,BDL, and 342.82 ± 591.20 mg/kg, respectively. Among the heavy metals, highest concentrations of Cu, Zn and Pb were found at urban sites-7(municipal waste dumping) and 8(medical waste incineration). Highest concentration of Cr followed by Cu and Zn was found at site-5(Tejgaon, urban). Principal component analysis revealed that anthropogenic activities are the potential sources for Cr, Ni, Cu, Zn and Pb while earth crust for Mn. Pollution index and pollution load index results suggested that all the sites were contaminated and/or degraded by Cr, Cu, Zn and Pb except sites-9(urban), 10(sub-urban), 11(rural) while sites-7 and 8(urban) were extremely degraded. For noncarcinogenic health risk, hazard quotient values for dermal were higher compared to that of inhalation/ingestion. Though hazard index values were less than 1 at all the sites, these were at least one order of magnitude higher for children group than that of adult group, thus the children group may face more noncarcinogenic health risk at sites -7 and 8. Values of incremental lifetime cancer risk were from 10to 10showed no carcinogenic health risk by road dusts contaminated with the heavy metals.

关键词： Heavy metal Road dust Dhaka Principal component analysis Pollution status Health risk assessment

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Legendre-Weighted Residual Methods for System of Fractional Order Differential Equations

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Journal of Applied Mathematics and Physics 2024年第9期12卷 3163-3184页

作者： Umme Ruman md. shafiqul islam Department of Computer Science & Engineering Green University of Bangladesh Dhaka Bangladesh Department of Applied Mathematics University of Dhaka Dhaka Bangladesh

The numerical approach for finding the solution of fractional order systems of boundary value problems (BPVs) is derived in this paper. The implementation of the weighted residuals such as Galerkin, Least Square, and Collocation methods are included for solving fractional order differential equations, which is broadened to acquire the approximate solutions of fractional order systems with differentiable polynomials, namely Legendre polynomials, as basis functions. The algorithm of the residual formulations of matrix form can be coded efficiently. The interpretation of Caputo fractional derivatives is employed here. We have demonstrated these methods numerically through a few examples of linear and nonlinear BVPs. The results in absolute errors show that the present method efficiently finds the numerical solutions of fractional order systems of differential equations.

关键词： Fractional Differential Equations System of Fractional Order BVPs Weighted Residual Methods Modified Legendre Polynomials

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Galerkin-Bernstein Approximations for the System of Third-Order Nonlinear Boundary Value Problems

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Journal of Applied Mathematics and Physics 2024年第6期12卷 2083-2101页

作者： Snigdha Dhar md. shafiqul islam Department of Applied Mathematics University of Dhaka Dhaka Bangladesh

This paper is devoted to find the numerical solutions of one dimensional general nonlinear system of third-order boundary value problems (BVPs) for the pair of functions using Galerkin weighted residual method. We derive mathematical formulations in matrix form, in detail, by exploiting Bernstein polynomials as basis functions. A reasonable accuracy is found when the proposed method is used on few examples. At the end of the study, a comparison is made between the approximate and exact solutions, and also with the solutions of the existing methods. Our results converge monotonically to the exact solutions. In addition, we show that the derived formulations may be applicable by reducing higher order complicated BVP into a lower order system of BVPs, and the performance of the numerical solutions is satisfactory. .

关键词： System of Third-Order BVP Galerkin Method Bernstein Polynomials Nonlinear BVP Higher-Order BVP

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Physico-chemical parameters for the assembly of moxifloxacin hydrochloride and cetyltrimethylammonium chloride mixture in aqueous and alcoholic media

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Chinese Journal of Chemical Engineering 2023年第5期57卷 280-289页

作者： Arnop Dutta md.Tuhinur R.Joy Sk.md.Ali Ahsan Mansour K.Gatasheh Dileep Kumar Malik Abdul Rub md.Anamul Hoque Mohammad Majibur Rahman Nasrul Hoda D.M.shafiqul islam Department of Chemistry Jahangirnagar UniversitySavarDhaka 1342Bangladesh Department of Chemistry Jashore University of Science and TechnologyJashore 7408Bangladesh Department of Biochemistry College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia Laboratory for Chemical Computation and Modeling Institute for Computational Science and Artificial IntelligenceVan Lang UniversityHo Chi Minh CityViet Nam Faculty of Applied Technology Van Lang UniversityHo Chi Minh CityViet Nam Center of Excellence for Advanced Materials Research King Abdulaziz UniversityJeddah 21589Saudi Arabia Chemistry Department Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Department of Environmental Sciences Jahangirnagar UniversitySavarDhaka 1342Bangladesh Department of Neurology Henry Ford Health SystemDetroitMI 48292USA

The aggregation behavior of the mixture of cetyltrimethylammonium chloride(CTAC), a cationic surfactant, and moxifloxacin hydrochloride(MFH), a fourth-generation fluoroquinolone antibiotic drug, has been studied using the conductivity technique in aqueous and alcoholic(EtOH, 1-PrOH, and 2-BuOH)media. The study was performed at several temperatures between 298.15 and 323.15 K at 5 K *** assembly has been characterized by evaluating the micellar parameters, such as the critical micelle concentration(CMC) and the counter ion binding(β), of the CTAC + MFH mixture. The values of the CMC for the assembly of the CTAC + MFH mixture were reliant on the composition of alcohols in the mixed solvents and the temperature. The CMC values of the CTAC + MFH mixture increased with increasing temperature;that is, assembly was delayed by increased temperature. The micellization of the CTAC + MFH mixed system was delayed in alcoholic media. The observed-ΔG0mvalues for the association of the CTAC + MFH mixed system demonstrated a spontaneous aggregation process under all study *** on the-ΔH^(0)_(m) and +ΔS^(0)_(m) values, the association of the CTAC + MFH mixture is exothermic and the interaction forces acting between the CTAC and MFH species are hydrophobic, ion–dipole, and electrostatic interactions. The transfer properties and enthalpy–entropy compensation were also assessed and described comprehensively.

关键词： Moxifloxacin hydrochloride drug Aggregation Alcohol Hydrophobic interaction Critical micelle concentration Thermodynamic properties

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Numerical Solutions of a Class of Second Order Boundary Value Problems on Using Bernoulli Polynomials

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Applied Mathematics 2011年第9期2卷 1059-1067页

作者： md. shafiqul islam Afroza Shirin 不详

The aim of this paper is to find the numerical solutions of the second order linear and nonlinear differential equations with Dirichlet, Neumann and Robin boundary conditions. We use the Bernoulli polynomials as linear combination to the approximate solutions of 2nd order boundary value problems. Here the Bernoulli polynomials over the interval [0,1] are chosen as trial functions so that care has been taken to satisfy the corresponding homogeneous form of the Dirichlet boundary conditions in the Galerkin weighted residual method. In addition to that the given differential equation over arbitrary finite domain [a,b] and the boundary conditions are converted into its equivalent form over the interval [0,1]. All the formulas are verified by considering numerical examples. The approximate solutions are compared with the exact solutions, and also with the solutions of the existing methods. A reliable good accuracy is obtained in all cases.

关键词： Galerkin Method Linear and Nonlinear BVP Bernoulli Polynomials

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孟加拉吉大港动物园恒河猕猴发生具有公共卫生重要性的结核病(英文)

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中国人兽共患病学报 2014年第9期30卷 909-912页

作者： md.shafiqul islam khan Farzana islam Rume md Mongur Morshed Chowdhury Mussammet Rasheda Begum md Robiul Karim Department of Food Microbiology Patuakhali Science and Technology University Patuakhali 8602 Bangladesh Department of Microbiology Patuakhali Science and Technology University Patuakhali 8602 Bangladesh Chittagong Zoo Chittagong 4225 Bangladesh Department of Agricultural Economics and Social Science Chittagong Veterinary and Animal Sciences University Chittagong 4225 Bangladesh 河南农业大学牧医工程学院寄生虫学研究室郑州450002

本调查自2012年7月至2012年9月在孟加拉吉大港动物园进行,确诊猴发生结核病。发病猴共46只,10至21月龄恒河猕猴表现出反应迟钝、明显消瘦的症状,皮内注射结核菌素,隔离检疫3天,仅有7只猴(15.22%)表现阳性结果。结核菌素阳性动物中,5只... 详细信息

本调查自2012年7月至2012年9月在孟加拉吉大港动物园进行,确诊猴发生结核病。发病猴共46只,10至21月龄恒河猕猴表现出反应迟钝、明显消瘦的症状,皮内注射结核菌素,隔离检疫3天,仅有7只猴(15.22%)表现阳性结果。结核菌素阳性动物中,5只在一个月内死亡,剖检检查在肺脏发现结核结节。肺脏样品萋尼氏抗酸染色和组织病理学检查,在染片中观察到抗酸染色的结核分枝杆菌,组织病理学观察到淋巴细胞、嗜中性白细胞和实质中高度增生的纤维组织围绕着上皮样巨噬细胞形成结核性肉芽肿,肺脏的肺泡壁增厚。上述检查结果证明猕猴发生结核病。

关键词：恒河猕猴结核病结核菌素组织病理学

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