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

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

作者： KHAN Abid Hossain islam m..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

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 m..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

Age at first marriage and its relation to fertility in Bangladesh

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Chinese Journal of Population,Resources and Environment 2013年第3期11卷 227-235页

作者： mosammat Zamilun Nahar mohammad Salim Zahangir S.m.shafiqul islam Department of Statistics University of Chittagong Department of Business Administration International Islamic University Chittagong

The 2007 Bangladesh Demographic and Health Survey(BDHS)data are exploited to examine the effects of socioeconomic and demographic factors on age at first marriage linkage to reproductive behavior of Bangladeshi *** mean age at first marriage of women is found to be 15.48 *** logistic regression technique shows that place of residence,religion,region,wealth index,education,and occupation are significantly important factors for determining age at first *** relationship between marriage and fertility suggests that women who marry at a younger age produce more children than women who marry *** of this study show that if the age at first marriage of adolescents is increased by 1 year,the age at first birth is postponed by 0.728 *** the increase in age at first marriage,the fecundability of women sharply rises,whereas the proportion of temporary sterility *** there is a positive association between age at first marriage and age-specific marital fertility rates,the total parity per woman at the end of the reproductive period is expected to reduce by 0.196 for each 1-year delayed marriage.

关键词： age at first marriage age at first birth fertility multivariate logistic regression life table analysis

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 m..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

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

Performance Analysis of Optical Wireless Communication System Employing Neuro-Fuzzy Based Spot-Diffusing Techniques

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Communications and Network 2013年第3期5卷 260-265页

作者： Shamim Al mamun m. Shamim Kaiser muhammad R Ahmed md. shafiqul islam md. Imdadul islam Department of Computer Science of Engineering Jahangirnagar University Savar Bangladesh Department of Physics Jahangirnagar University Savar Bangladesh Institute of Information Technology Jahangirnagar University Savar Bangladesh School of Information Technology & Engineering University of Canberra Australia

The spot-diffusing technique provides better performance compared to conventional diffuse system for indoor optical-wireless communication (OWC) system. In this paper, the performance of an OW spot-diffusing communication system using Neuro-Fuzzy (NF) adaptive multi-beam transmitter configuration has been proposed. The multi-beam transmitter generates multiple spots pointed in different directions, hence, forming a matrix of diffusing spots based on position of the receiver and receiver mobility. Regardless of the position of the transmitter and receiver, NF controller target the spots adaptively at the best locations and allocates optimal power to the spots and beam angle are adapted in order to achieve better signal-to-noise plus interference ratio (SNIR). maximum ratio combining (mRC) is used in the imaging receiver. The proposed OW spot-diffusing communication system is compared with other spot-beam diffusion methods proposed in literature. Performance evaluation revels that the proposed NF based OW spot-diffusing communication system outperforms other spot-beam diffusion methods.

关键词： Optical-wireless Communication Spot Diffusion Technique Neuro-fuzzy Imaging Receiver Adaptive Power Allocation

Status of multielement in water of the river Buriganga, Bangladesh: Aquatic chemistry of metal ions in polluted river water

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Emerging Contaminants 2021年第1期7卷 99-115页

作者： Aklima Nargis Ahsan Habib Harun-Or-Rashid Halima Binte Harun m..shafiqul islam Sarker Rong Jin Guorui Liu Wenbin Liu A.N.m.Al-Razee Kai Chen minggang Cai Coastal and Ocean management Institute Xiamen UniversityXiamenPR China Department of Chemistry University of DhakaDhaka1000Bangladesh Central Chemical Laboratory Department of Narcotics ControlMinistry of Home AffairsDhaka1204Bangladesh Sate Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental ScienecsChinese Academy of SciencesBeijing100085PR China Department of Analytical Chemistry&Environmental Science Training Institute for Chemical IndustriesPolashBangladesh

The peripheral rivers of Dhaka city became highly polluted because of industrialization and urbanization to a greater extent in the last few ***,an attempt has been taken to measure 48 elements in water of the river Buriganga using the ICP-mS method for the first ***,it could be the reference values for future research in *** of the 48 elements,the following metals are given more attention because of their detrimental effects on living organisms and for discussing their aquatic chemistry in polluted water body:Be,Na,Al,Cr,mn,Fe,Ni,Cu,Zn,Cd,Ba,Hg,Pb,Bi and *** revealed that metals’concentrations in water in the monsoon were less than that of the winter,however,Cr and Fe were found at below detection limits in the winter that is *** parameters of the river water such as pH,dissolved oxygen play vital roles for hydrolysis reactions in the stagnant water *** products of metal ions having low values of solubility products(K sp),for example,iron(III)hydroxide,chromium(III)hydroxide,phase out through precipitation *** study also detects and quantifies total concentrations of Hg and U in water of the river Buriganga for the first *** and correlation matrix results provided potential sources of the relevant *** of hydrolysis and precipitation reactions for metal ions in the polluted river water are also discussed.

关键词： hydrolysis winter river

Radiological Concentration Distribution of <sup>134</sup>Cs and <sup>137</sup>Cs Due to a Hypothetical Accident of TRIGA Research Reactor

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World Journal of Nuclear Science and Technology 2021年第3期11卷 119-131页

作者： Arif Jahan Sarawer m. Ajijul Hoq m. Abu Khaer m..shafiqul islam m. mominur Rahman m. Tareque Chowdhury m. mizanur Rahman Department of Physics Jahangirnagar University of Bangladesh Dhaka Bangladesh Institute of Energy Science Atomic Energy Research Establishment Bangladesh Atomic Energy Commission Dhaka Bangladesh

The assessment of the radiological concentration of 134Cs and 137Cs owing to hypothetical accident of TRIGA mark-II research Reactor at AERE, Savar, Bangladesh is presented here in this work. The concentration of 134Cs and 137Cs was estimated in different pathways consisting of the ingestion of plants, milk, and meat. The highest air concentration has been determined at 65 m distance from the core of the reactor. The maximum concentration passed off without delay simply after the accident in various directions. Local meteorological information such as average wind velocity and wind frequency were analyzed. Considering all directions, the highest concentration has been observed in the “S” direction. The concentrations of 134Cs and 137Cs were determined in ground, vegetation, milk and meat. The concentration of 137Cs is investigated to be higher than the 134Cs. The concentration of 134Cs and 137Cs was found to be lower in vegetation, milk, and meat than that of ground concentration. Overall, in this study, the concentration in meat has been investigated to be lower. In case of a reactor accident, the concentration assessment due to the ingestion of vegetables, milk, and meat will be a valuable guide for insuring radiological protection across the research reactor at AERE, Savar, Bangladesh.

关键词： Concentration Hypothetical Accident Pathway Radiological Protection TRIGA mark-II

超声振动对5A06铝合金自冲铆接头静力学性能影响

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材料科学与工艺 2023年第2期31卷 44-49页

作者：霍小乐赵伦许龙周光平蔡景 shafiqul islam 郭子鑫林森中国计量大学理学院杭州310018 深圳职业技术学院智能制造技术研究院广东深圳5180553 瑞典布京理工大学机械工程学院卡尔斯克鲁纳37179

自冲铆接工艺作为一种性能优异、绿色、高效的连接新技术,可实现同种、异种和多层轻合金薄板材料的连接,广泛应用于新能源汽车等领域,成为实现车身轻量化的关键技术之一。但由于自冲铆接头是典型的紧密连接构件,在交变应力或振动作用下... 详细信息

自冲铆接工艺作为一种性能优异、绿色、高效的连接新技术,可实现同种、异种和多层轻合金薄板材料的连接,广泛应用于新能源汽车等领域,成为实现车身轻量化的关键技术之一。但由于自冲铆接头是典型的紧密连接构件,在交变应力或振动作用下,易发生微动损伤,致使接头提前疲劳失效。本文选用5A06铝合金薄板材料,分别进行自冲铆接和不同超声焊接工具头下的超声自冲铆复合连接试验,基于拉伸-剪切和电子显微镜测试,研究超声振动对5A06铝合金自冲铆接头静力学性能的影响。研究表明:超声振动可有效提高自冲铆接头的静力学性能;超声金属焊接与自冲铆接复合连接时会在板材之间形成固相焊接,这是提高复合接头力学性能的根本原因;超声金属焊接头的焊接面积影响自冲铆接头的力学性能,焊接面积较大时超声固相焊的程度较高;超声焊接会使铆钉温度升高,一定程度影响接头稳定性。

关键词：超声振动自冲铆接 5A06 静力学性能轻量化