检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Acute Lymphoblastic Leukemia Presenting as Systemic Juvenile Idiopathic Arthritis: Experience from Bangladesh

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Rheumatology and Autoimmune Diseases 2024年第1期14卷 1-12页

作者： Manik Kumar Talukder Kamrul Laila md. Arif Hossain md. shafiqul islam md. Zahidul islam Kalyan Benjamin Gomes Mujammel Haque md. Mahbubul islam md. Imnul islam Department of Paediatrics Bangabandhu Sheikh Mujib Medical University Dhaka Bangladesh Health Services Dhaka Bangladesh NICVD Dhaka Bangladesh

Background: Acute lymphoblastic leukemia (ALL), the most common paediatric malignancy, is a heterogeneous hematologic disease. ALL patients may present with isolated and persistent osteo-articular complaints, lower incidence of hepatomegaly, splenomegaly or lymphadenopathy without clear laboratory features, and misdiagnosed as systemic juvenile idiopathic arthritis (sJIA). Methods: This was a single center cross sectional study over a period of 4 years. Clinic laboratory profiles of 39 ALL children were compared with 39 age and sex-matched sJIA cases. Result: Among 39 ALL patients 89.7% were initially misdiagnosed as sJIA upon clinical presentation. Majority (66.7%) of ALL patients had oligo-articular joint involvement. In sJIA, small joints of the hands were most commonly involved. The total WBC count was significantly higher in ALL patients (p-value 0.0065). CRP and LDH values between the two groups showed significant differences (p-value 0.00006 and 0.00001 respectively). Conclusion: The presentation of leukemia with arthralgia or arthritis makes the diagnosis difficult for the physicians. The diagnosis of sJIA must be made with caution keeping the possibility of haematological malignancy in mind.

关键词： ALL sJIA Arthritis Arthralgia Musculoskeletal

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Quantifying River Bank Erosion and Accretion Patterns along the Gorai River in Kushtia, Bangladesh: A Geospatial Analysis Utilizing GIS and Remote Sensing Techniques

在线全文

学校读者我要写书评

暂无评论

Journal of Geographic Information System 2024年第1期16卷 70-88页

作者： Chisti Muzahid Samsunnahar Popy Rifat islam md. shafiqul Ahsan Emon md. Selim Reja md. Mustafizur Rahman Jubayer Hoque md. Golam Rabbani Saim Raiyan Department of Environmental Science and Disaster Management Bangabandhu Sheikh Mujibur Rahman Science and Technology University Dhaka Bangladesh

River bank erosion is a natural process that occurs when the water flow of a river exceeds the bank’s ability to withstand it. It is a common phenomenon that causes extensive land damage, displacement of people, loss of crops, and infrastructure damage. The Gorai River, situated on the right bank of the Ganges, is a significant branch of the river that flows into the Bay of Bengal via the Mathumati and Baleswar rivers. The erosion of the banks of the Gorai River in Kushtia district is not a recent occurrence. Local residents have been dealing with this issue for the past hundred years, and according to the elderly members of the community, the erosion has become more severe activities. Therefore, the main objective of this research is to quantify river bank erosion and accretion and bankline shifting from 2003 to 2022 using multi-temporal Landsat images data with GIS and remote sensing technique. Bank-line migration occurs as a result of the interplay and interconnectedness of various factors such as the degree of river-related processes such as erosion, transportation, and deposition, the amount of water in the river during the high season, the geological and soil makeup, and human intervention in the river. The results show that the highest eroded area was 4.6 square kilometers during the period of 2016 to 2019, while the highest accreted area was 7.12 square kilometers during the period of 2013 to 2016. However, the erosion and accretion values fluctuated from year to year.

关键词： Erosion and Accretion Geographic Information System (GIS) Remote Sensing Satellite Image Bankline Shifting

Rural Resilience: A Comprehensive Study on Water Supply, Sanitation, Disease Patterns, and Hygiene Practices in Munshiganj, Bangladesh

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Protection 2024年第1期15卷 63-75页

作者： Jubayer Hoque Rifat islam md. Mustafizur Rahman md. Golam Rabbani md. Selim Reja Saifur Rahman Soykat Saim Raiyan md. shafiqul Ahsan Emon Sakil Khan Department of Environmental Science and Disaster Management Bangabandhu Sheikh Mujibur Rahman Science and Technology University Gopalgnj Bangladesh Department of Political Science Bangabandhu Sheikh Mujibur Rahman Science and Technology University GopalgnjBangladesh Department of Statistics Bangabandhu Sheikh Mujibur Rahman Science and Technology University Gopalgnj Bangladesh

This research project investigates the current status of water supply, sanitation, and hygiene practices in Munshiganj District, Bangladesh. Data collection involved a structured questionnaire and a reconnaissance survey. Findings reveal that 30% of individuals rely on surface water (hand-tube wells, rivers, and ponds), prioritized as canal > river > pond, while 70% depend on groundwater (subterranean electric motor, deep tube-well). Drinking water is generally sufficient, with 95% reporting adequacy throughout the year. About 45% use hand tube-well water, 28% use deep tube-well water, and 11% use supply tap water for various purposes. Bathing trends include underground water through electric motor > pond > hand tube-well water > river, while for cooking, the order is underground water through electric motor > pond > hand tube-well water > river. Toilet water supply ranks as supply tap water > hand tube-well water > deep tube-well water. Although sanitation awareness is high, some lack knowledge of good hygiene practices. After defecating, handwashing methods include soap, ash, soil, or water. Children’s waste disposal varies, with some discarding it in open areas. Approximately 40% suffer from diseases like Diarrhoea due to unsafe water, primarily affecting children and elders. Training exists, but a significant portion lacks sanitation education. Dry skin or exposure to cold water may cause temporary irritation. Local government involvement in sanitation efforts is less active compared to non-governmental organizations. Results emphasize the need to enhance community awareness of safe water supplies and sanitation practices. .

关键词： Water Supply Sanitation Practices Hygiene Awareness Groundwater Dependency Community Health Intervention

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

不同铜线芯直径超声波焊接头性能的研究

兵器材料科学与工程 2024年第5期47卷 8-12页

作者：沈中华张永祺赵伦龚涛梁召峰许龙周光平 md.shafiqul islam 广西高校先进制造与自动化技术重点实验室广西桂林541006 深圳职业技术大学超声技术研究所广东深圳518055 瑞典布京理工学院机械学院布莱金厄卡尔斯克鲁纳37179

对3种不同的线芯直径的10 mm双铜(Cu)导线接头进行超声波焊接试验。通过剥离试验、孔隙率计算、温度测量、扫描电子显微镜(SEM)研究分析了铜导线接头性能和失效形式。结果表明:线芯直径与接头抗剥离力正相关,线芯直径越粗接头力学性能... 详细信息

对3种不同的线芯直径的10 mm双铜(Cu)导线接头进行超声波焊接试验。通过剥离试验、孔隙率计算、温度测量、扫描电子显微镜(SEM)研究分析了铜导线接头性能和失效形式。结果表明:线芯直径与接头抗剥离力正相关,线芯直径越粗接头力学性能越好。两根线芯直径为0.1 mm导线焊接的接头抗剥离强度未达标,失效形式为结合面完全分离无线芯断裂。直径增至0.2 mm时,接头抗剥离强度均达到标准,失效形式变为结合面处线芯的韧性断裂。焊接时的峰值温度有效影响了接头孔隙率,但孔隙率并不能完全作为判断接头成型质量的依据,部分导线在高温下仅发生塑性变形,而未能实现原子键合。此外,通过观察接头剖面发现,焊接接头形成了外紧内松的结构,与压块接触的接头上侧和与焊头接触的接头下侧几乎无空隙,而接头中间内侧则存在大量空隙。

关键词：超声波焊接铜导线力学行为断口形貌

在线全文

学校读者我要写书评

暂无评论

镁-铝异种合金自冲铆接接头的力学性能

锻压技术 2024年第9期49卷 157-163+185页

作者：卢杰豪赵伦张俊凯雷乐李承旺刘高宇刘纪元 md.shafiqul islam 深圳职业技术大学超声技术研究所辽宁科技大学材料与冶金学院云南开放大学机电工程学院瑞典布京理工学院机械学院

镁合金材料在车身轻量化制造方面具有巨大的潜力和应用空间，选取不同厚度的AZ31B镁合金和5083铝合金薄板材料进行自冲铆接，并通过拉伸实验和扫描电镜分析接头的静力学性能及微观组织。结果表明：自冲铆接能实现对AZ31B镁合金和5083铝... 详细信息

镁合金材料在车身轻量化制造方面具有巨大的潜力和应用空间，选取不同厚度的AZ31B镁合金和5083铝合金薄板材料进行自冲铆接，并通过拉伸实验和扫描电镜分析接头的静力学性能及微观组织。结果表明：自冲铆接能实现对AZ31B镁合金和5083铝合金薄板的有效连接；板厚搭配均匀的自冲铆接接头的整体力学性能最优；镁板厚度较小的自冲铆接接头的失效形式均为上板断裂，其余两组自冲铆接接头的失效形式均为下板拉脱；3组不同镁板厚度组合的自冲铆接接头断口均呈脆性断裂形貌。

关键词：车身轻量化自冲铆接镁合金铝合金力学性能

超声波焊接能量对大直径线束-端子接头性能影响

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

应用声学 2024年第4期43卷 799-806页

作者：许龙洪宛璐赵伦李承旺雷乐张溟晨梁召峰周光平 md.shafiqul islam 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深圳518055 瑞典布京理工学院机械学院卡尔斯克鲁纳37179

线束与端子的连接技术在新能源汽车上的需求日益增大。传统连接方式存在耗能高、性能不稳定、产生污染等缺点,因此超声波焊接技术被推广应用到新能源汽车的线束连接上。该文以EVRP5平方屏蔽高压线为研究对象,采用单一变量法对线束进行... 详细信息

线束与端子的连接技术在新能源汽车上的需求日益增大。传统连接方式存在耗能高、性能不稳定、产生污染等缺点,因此超声波焊接技术被推广应用到新能源汽车的线束连接上。该文以EVRP5平方屏蔽高压线为研究对象,采用单一变量法对线束进行超声波焊接试验,以焊接能量为变量,通过力学性能测试、微观分析和超声波检测分析超声波的焊接机理。试验结果表明,当焊接能量为5 kJ时,接头抗拉力为2616 N;当焊接能量为11 kJ时,接头抗拉力提高至6650 N。在一定范围内,随着焊接能量的不断增大,接头由靠近工具头处和焊接界面处向内,由未连接状态到点连接、线连接、面连接最终逐渐形成原子间键合。

关键词：超声波焊接线束焊接能量力学性能