检索结果-南通市图书馆

Seasonal influence of freshwater discharge on spatio-temporal variations in primary productivity, sea surface temperature, and euphotic zone depth in the northern Bay of Bengal

引用

Acta Oceanologica Sinica 2024年第6期43卷 1-14页

作者： Hafez Ahmad Felix Jose md.simul bhuyan md.Nazrul Islam Padmanava Dash Geosystems Research Institute/Department of Geosciences Mississippi State UniversityStarkville 39759USA Department of Oceanography University of ChittagongChittagong 4331Bangladesh Department of Marine&Earth Sciences Florida Gulf Coast UniversityFort Myers 33965USA Bangladesh Oceanographic Research Institute Cox’s Bazar 4730Bangladesh Faculty of Marine Sciences&Fisheries Institute of Marine SciencesUniversity of ChittagongChittagong 4331Bangladesh Department of Geography and Environment Jahangirnagar UniversityDhaka 1342Bangladesh Department of Geosciences Mississippi State UniversityStarkville 39759USA

Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on ***-temporal variability of net primary productivity(NPP),sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),and euphotic zone depth(EZD) in the northern B ay of Bengal(BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to *** compare the NPP distribution between the coastal zones and open BoB,the study area was divided into five zones(Z1-Z5).Results suggest that most productive zones Z2 and Zl are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient *** Z1-Z5,the NPP ranges from 5 315.38 mg/(m^(2)·d) to 346.7 mg/(m^(2)·d)(carbon,since then the same).The highest monthly average NPP of 5 315.38 mg/(m^(2)·d) in February and 5 039.36 mg/(m^(2)·d) in June were observed from Z2,while the lowest monthly average of 346.72 mg/(m^(2)·d) was observed in March from Z4,which is an oceanic *** values vary from 6-154 m for the study area,and it has an inverse correlation with NPP *** is deeper during the summer season and shallower during the wintertime,with a corresponding increase in *** the year,monthly SST shows slight fluctuation for the entire study area,and statistical analysis shows a significant correlation among NPP,and EZD,overall positive between NPP and MLD,whereas no significant correlation among SSS,and SST for the northern ***-term trends in SST and productivity were significantly po sitive in head bay zones but negatively productive in the open *** findings in this study on the distribution of NPP,SST,SSS,MLD,and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to clim

关键词： chlorophyll a sea surface temperature euphotic zone depth primary productivity Ganges-Brahmaputra ocean color Bay of Bengal monsoon

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effectiveness of hybrid ensemble machine learning models for landslide susceptibility analysis:Evidence from Shimla district of North-west Indian Himalayan region

引用

Journal of Mountain Science 2024年第7期21卷 2368-2393页

作者： SHARMA Aastha SAJJAD Haroon RAHAMAN md Hibjur SAHA Tamal Kanti bhuyan Nirsobha Department of Geography Faculty of SciencesJamia Millia IslamiaNew Delhi-110025India

The Indian Himalayan region is frequently experiencing climate change-induced ***,landslide susceptibility assessment assumes greater significance for lessening the impact of a landslide *** paper makes an attempt to assess landslide susceptibility in Shimla district of the northwest Indian Himalayan *** examined the effectiveness of random forest(RF),multilayer perceptron(MLP),sequential minimal optimization regression(SMOreg)and bagging ensemble(B-RF,BSMOreg,B-MLP)models.A landslide inventory map comprising 1052 locations of past landslide occurrences was classified into training(70%)and testing(30%)*** site-specific influencing factors were selected by employing a multicollinearity *** relationship between past landslide occurrences and influencing factors was established using the frequency ratio *** effectiveness of machine learning models was verified through performance *** landslide susceptibility maps were validated by the area under the receiver operating characteristic curves(ROC-AUC),accuracy,precision,recall and *** key performance metrics and map validation demonstrated that the BRF model(correlation coefficient:0.988,mean absolute error:0.010,root mean square error:0.058,relative absolute error:2.964,ROC-AUC:0.947,accuracy:0.778,precision:0.819,recall:0.917 and F-1 score:0.865)outperformed the single classifiers and other bagging ensemble models for landslide *** results show that the largest area was found under the very high susceptibility zone(33.87%),followed by the low(27.30%),high(20.68%)and moderate(18.16%)susceptibility *** factors,namely average annual rainfall,slope,lithology,soil texture and earthquake magnitude have been identified as the influencing factors for very high landslide *** texture,lineament density and elevation have been attributed to high and moderate ***,the study calls for devising suitable landslide mitig

关键词： Landslide susceptibility Site-specific factors Machine learning models Hybrid ensemble learning Geospatial techniques Himalayan region

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microplastic pollution:An emerging contaminant in aquaculture

引用

Aquaculture and Fisheries 2023年第6期8卷 603-616页

作者： Stanley Iheanacho Miracle Ogbu md.simul bhuyan Johnny Ogunji Department of Fisheries and Aquaculture Alex Ekwueme Federal UniversityNdufu Alike Ebonyi StateAbakalikiP.M.B.1010Nigeri Department of Biology Alex Ekwueme Federal UniversityNdufu Alike Ebonyi StateAbakalikiP.M.B.1010Nigeria Bangladesh Oceanographic Research Institute Cox’s Bazar4730Bangladesh

Aquaculture largely contributes to aquatic products and consequential dietary protein for many ***,just like every other food sector,is faced with enormous challenges such as unfavorable climatic events,environmental stressors and ***(MP)are emerging contaminants in aquaculture following their perturbing occurrence in cultured fish,fishmeal and *** MPs pathways into aquaculture facilities include wastewater,pipe-borne water,dilapidated aquaculture facilities,fish gears,and aquafeed stuff(fishmeal).Techniques for the digestion,identification and characterization of MPs are critical to understanding their pathways,bioavailability and bioaccumulation patterns in aquaculture *** impacts of MPs on cultured fish species are identified as impaired growth,oxidative stress,neurotoxicity,reproductive toxicity,immunotoxicity,embryotoxicity,and *** of MPs in tissues and biological systems have been evidenced in several cultured *** efforts cum strategies such as upgrade of wastewater treatment facilities,screening of inlet pond water,screening of aquafeed stuff,regular maintenance and repair of culture facilities,could be effective to eradicate MP contamination in ***,regulatory policy on the use of plastics is key to mitigating the impact of MPs and ensure cleaner and sustainable aquaculture.

关键词： Microplastics Aquaculture Sources Impact Mitigation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Seismic Performance Assessment of Reinforced Concrete Box Culverts under Near and Far Fault Seismic Ground Motion Records

引用

World Journal of Engineering and Technology 2022年第1期10卷 40-58页

作者： Lawali Moussa Laminou Wadslin Frenelus md Ratan Bhuiyan md Ibrahim bhuyan Department of Civil Engineering College of Civil Engineering and Architecture China Three Gorges University Yichang China Department of Hydraulic Engineering College of Hydraulic and Environmental Engineering China Three Gorges University Yichang China

Studying the critical response characteristics of reinforced concrete box culverts with diverse geometrical configurations under seismic excitations is a necessary step to develop a reasonable design method. In this work, numerical analysis and assessment of reinforced concrete box culverts for seismic loading in addition to standard static loading from dead and live loads is conducted, aiming to highlight the critical difference in the seismic performances between two and three cell box culverts under near and far-fault ground motion. The results show how and where the seismic loading alters the responses of seismic loading of the models including the effect on safety and failure. The geometrical configurations of the culvert combined with the loading scenarios also significantly influence the magnitude and distribution of the seismic responses. The findings of this work shed light on the critical role of the geometrical configurations and shaking event in the seismic responses of reinforced concrete box culverts and this procedure can be applied as seismic assessment method to any culvert shape, size, and material.

关键词： Box Culvert Seismic Loading Near-Fault Ground Motion Far-Fault Ground Motion Seismic Assessment

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Increasing yield and agronomic efficiency of boro rice(Oryza sativa)by fertigation with bed planting compared with conventional planting

引用

International Journal of Agricultural and Biological Engineering 2014年第5期7卷 34-47页

作者： md.Halim Mahmud bhuyan Most.Razina Ferdousi md.Toufiq Iqbal Department of Farm Machinery Chuadanga Technical School and CollegeChuadanga 7200Bangladesh Islamia Academy High School&Agriculture College BaghaRajshahi 6280Bangladesh Department of Agronomy and Agricultural Extension University of RajshahiRajshahi 6205Bangladesh

The fertigation technique with raised bed planting for transplanted boro(winter,irrigated)rice production is a research focus nowadays.A field experiment compared two cultivation methods:the fertigation technique within raised bed planting on boro rice,and fertilizer broadcasting in the conventional planting *** to conventional fertilizer broadcasting,results showed that the new fertigation technique in raised bed planting increased grain yield of transplanted boro rice by up to 17.04%.It yielded a greater number of panicles per square meter,a greater number of grains per panicle,higher 1000-grains weight,and better plant growth *** percentage and weed infestation were *** six percent of irrigation water and time for application could be *** use efficiency for grain and biomass production was *** agronomic efficiency of nitrogen(N)fertilizer was significantly *** study concluded that fertigation in raised bed planting for transplanted boro rice is a new approach with higher yield and higher fertilizer and water use efficiency than the existing agronomic practice in Bangladesh.

关键词： boro rice fertigation with bed planting de-nitrification water use efficiency harvest index irrigated water management

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

simulation of Heat Transfer in a Tubular Pipe Using Different Twisted Tape Inserts

引用

Open Journal of Fluid Dynamics 2017年第3期7卷 397-409页

作者： md. Moniruzzaman bhuyan Ujjwal K. Deb M. Shahriar simul Acherjee Department Electrical & Electronics Engineering Southern University Bangladesh Chittagong Bangladesh Department of Mathematics Chittagong University of Engineering & Technology Chittagong Bangladesh Department of Mechanical Engineering Chittagong University of Engineering & Technology Chittagong Bangladesh Department of Mathematics Narangiri Govt. High School Chittagong Bangladesh

This paper performs a simulation study of the heat transfer phenomena in a tubular U-loop pipe. We have investigated the enhancement of heat transfer with mass flow in a pipe without insert, with full length and short length twisted tape inserts. The length of the pipe is approximately 2436.80 mm long with 29 mm inner and 33 mm outer diameter respectively. A constant heat flux is taken which generated the boundary layer of the pipe close to the flowing fluid around the boundary. The simulations are considered for the stationary and the time dependent module for 35 seconds with different length of inserts. The comparisons are made among the results. We observed that the transfer of heat is enhanced significantly with the increase of the length of inserts inside the computational domain. We also found that, full length twisted tape inserts are more effective than comparing with the short length inserts and without insert.

关键词： Heat Transfer Non-Isothermal Flow Tubular Pipe Twisted Tape Inserts simulation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Trend Analysis of Temperature and Rainfall to Predict Climate Change for Northwestern Region of Bangladesh

引用

American Journal of Climate Change 2018年第2期7卷 115-134页

作者： md. Didarul Islam bhuyan md. Mohymenul Islam md. Ebrahim Khalil Bhuiyan Department of Physics Mawlana Bhashani Science and Technology University Santosh Tangail Bangladesh Department of Textile Engineering Bangladesh University of Business and Technology Dhaka Bangladesh

Bangladesh is one in all the foremost climate vulnerable countries of the world. In recent years, climate change studies over the country get plenty of attention by the researchers and policy makers. A substantial quantity of global climate change studies over the country use climate models to estimate future projections and uncertainties. Maximum temperature, precipitation and their potential future changes are evaluated in an ensemble of the 5th Phase Coupled Model Inter-comparison Project (CMIP5) within the Intergovernmental Panel on Climate Change (IPCC) diagnostic exercise for the Fifth Assessment Report (AR5) and the available historical data collected by the Bangladesh Meteorological Department (Bmd) during the period 1981-2008 in the north-western region of Bangladesh and also the comparison between these two values. It has been found that average maximum temperature shows a positive trend of increase at a rate of 0.29°C and 5.3°C per century respectively, for Bmd data and MPI-ESM-LR (CMIP5) model data. But the rainfall is decreasing at a rate of 8.8 mm and 40.1 mm per century respectively for Bmd data and MPI-ESM-LR (CMIP5) model data. It is seen that July was the maximum monsoon rainfall month and January was the lowest rainfall month. The peak frequency is slightly smaller than 12 months, which indicates that the major events are occurring before ending a year compared to the previous year. According to MPI-ESM-LR (CMIP5) model data, future normal temperature on north-western region will be increased at a rate of 1.62°C during the period 2040-2100.

关键词： Trend Analysis Mann-Kendall Test Sen’s Slope Estimator Z-Test CMIP5 Model and Periodicity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Augmentation of Heat Transfer in Pipe Flow Using Plain Twisted Tape Inserts for Different Twist Ratios

引用

Energy and Power Engineering 2019年第9期11卷 342-354页

作者： Maimonul Karim Chowdhury md. Moniruzzaman bhuyan Ujjwal Kumar Deb Department of Science & Humanities Military Institute of Science and Technology Mirpur Cantonment Dhaka Bangladesh Department of Mathematics Chittagong University of Engineering & Technology Chittagong Bangladesh

The heat transfer augmentation of plain twisted tape inserts for different twist ratios has been studied in this study. The data are conducted using the plain twisted tape insert with five different twist ratios respectively. The range of Reynolds number is considered under a uniform heat flux condition. In the case of simulation, the tapes are made from a stainless steel strip with a thickness of 2 mm. A tubular pipe with 850mm U-loop length and twist length of 800 mm each is considered in our study for simulation. Water is used as working fluids inside the tube for our simulation. The simulation results demonstrate that the important heat transfer parameters including Nusselt number (Nu), friction factor (f) and thermal performance index (η) are gradually increased with the increment of the twist ratio and reached at the saturated level while twist ratio is 3.5,?afterward the thermal properties are decreased.

关键词： Heat Transfer Twist Ratio Reynolds Number Turbulent Flow simulation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：