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Journal of Geoscience and Environment Protection 2022年第4期10卷 82-100页

作者： md. Kabirul Islam md. munsur rahman Department of Civil Engineering Military Institute of Science and Technology (MIST) Dhaka Bangladesh Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka Bangladesh

The Payra is a tidal river with meandering planform in which around 6.5 km long landmass is formed naturally during the last 40 years that is selected for an establishment by the Government of Bangladesh. However, the site experiences intermittent erosion at several locations and poses threat to the newly developed infrastructures. In the present study, a Rouse type simple model is used to estimate the equilibrium profiles of suspended sediment concentration below which the system is likely to be eroded and regarded as “Sediment Deficit System, SDS” and above which the system is likely to be sedimented and regarded as “Sediment Surplus System, SSS”. The model was then tested at the study reach using the measured flow-sediment data complemented by field observation and Landsat images-based planform analysis. The analysis revealed that the residual flow-sediment regime in the study site is representing the “sediment deficit system” that causes continuous threat for erosion throughout the tidal cycles. Therefore, the availability of new landmass should not be the only criterion for the quick selection of a project site, and residual flow-sediment regime needs to consider as an additional parameter for such decision-making process.

关键词： Suspended Sediment Concentration Sediment Surplus System Sediment Deficit System Residual Flow-Sediment Regime

SCOUR MITIGATION AT BRIDGE PIERS USING SACRIFICIAL PILES

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International Journal of Sediment Research 2007年第1期22卷 49-59页

作者： M. Anisul HAQUE md. munsur rahman G.M. Tarekul ISLAM M. Asad HUSSAIN Prof.Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh Assoc. Prof.Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh Lecturer Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh

To mitigate scour around bridge piers, sacrificial piles are economic method where natural processes are involved. The arrangement should be such that scoured materials from the sacrificial piles should have enough volume to fill the scour hole created upstream of the pier in such a way that sediments are trapped inside the scour hole. This concept differs from earlier study made with sacrificial piles that mainly deals to reduce the strength of horseshoe vortex. To determine the effect of sacrificial piles for scour mitigation, alternative arrangements of piles were tested in front of a rectangular pier under clear-water condition and found that when the group of piles is placed at a distance of twice the projected width of the pier, for which percentage of blockage of the pier width is 60%, the scour volume can be reduced upto 61% while the maximum scour depth can be reduced upto 50%.

关键词： Scour mitigation Bridge pier Sacrificial pile Optimum arrangement

Functioning Hydraulic and Morphological Sustainability of River Training Works in Bangladesh

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Journal of Civil Engineering and Architecture 2013年第6期7卷 756-766页

作者： md. Mosiur rahman md. Abu Hena Mostofa Kamal md. munsur rahman Institute of Water and Flood Management Bangladesh University of Engineering and Technology (BUET) Dhaka 1000Bangladesh Department of Civil Engineering Rajshahi University of Engineering and Technology (RUET) Rajshahi 6204 Bangladesh

River dynamics play the most vital role in the socio-economic of the country. These rivers are highly dynamic in nature which causes extensive riverbank erosion. Active river bank erosion and bed scouring, is apprehended to change the scenario, leading to loss of limited valuable land of Bangladesh. River training is being practiced in Bangladesh since 1960s but the process is very expensive especially in the Ganges and the Jamuna Rivers. Five types of river training works were selected at different reaches. Hydro-morphological characteristics of the major rivers are being evaluated not only in engineering concepts but also in socio-economic and environmental aspects. PRA （participatory rural appraisal） tools were applied to evaluate protection safety, hydraulic and hydrological connectivity, ecological and environmental characteristics, causes of failure and social acceptability. This comparative study is being carried out for closing the gap between the modem river training works and in country experience through adaptation of research findings with a view to effectively arresting river bank erosion. Sirajganj Hardpoint, Chandpur Town Protection work and Nakalia Revetment are found to be suitable and effective. A technically suitable structure may not have good social acceptance without IWRM （integrated water resource management）.

关键词： Sustainability river training works river morphology socio-economic PRA tools IWRM.

LOCAL SCOUR ESTIMATION AT BRIDGE SITE: MODIFICATION AND APPLICATION OF LACEY FORMULA

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International Journal of Sediment Research 2003年第4期18卷 333-339页

作者： md. munsur rahman,iwfm.buet.ac.bd at present: Post Doctoral Research fellow, Ujigawa Open Laboratory, Disaster Prevention Research Institute, Kyoto University, Shimomisu, Yoko-Oji, Fushimi-Ku, Kyoto 612-8235, Japan ,M. Anisul HAQUE Assistant Professor Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh E-mail: mmrahman Associate Professor Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh

In the recent years, it has been established that b/h or h/b (b = length of the structure in the lateral direction and h = approach flow depth) is the dominant factor for the estimation of local scour depth around abutments and piers. One of the major limitations of the Lacey formula is that it predicts only one value of the scour depth for a specific river because of the absence of important parameters b and h. Therefore, its application is quite uncertain for variable b and h. Considering its limitations and experimental facts of flow concentration and shear stress amplification close to above structures, the original Lacey formula is modified introducing the parameters b and h. The applicability of the original as well as modified Lacey formula is tested to the data collected from major rivers in Bangladesh.

关键词： Local scour depth Piers and abutments Lacey formula Bangladesh

Flow and erosion at a bend in the braided Jamuna River

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International Journal of Sediment Research 2012年第4期27卷 498-509页

作者： Mohammad Nazim UDDIN md.munsur rahman Department of Civil Engineering Dhaka University of Engineering and Technology Institute of Water and Flood Management Bangladesh University of Engineering and Technology

The braided Jamuna River frequently changes its *** the secondary channel in a braided river acts as a single thread meandering *** the present study an attempt has been made to investigate the flow patterns and to estimate the rate of bank erosion in a bend along the Jamuna *** three dimensional(3D) flow velocities were measured using Acoustic Doppler Current Profiler(ADCP).It is found that the near bank velocity is amplified by 1.1 to 1.3 times as compared with the section averaged velocity.A dominant secondary current is found in the upstream *** evolution as well as decay of the secondary current is not as clear as it is found in the laboratory *** is revealed from the analysis of the flow process that the causes of higher rate of erosion at the study bend are the oblique flow near bankline,six times amplified shear velocity than critical shear velocity near bankline and the secondary current which acts as a sediment transporting agent from the outer bank towards the inner bank or the sand *** on the flow processes,a simplified erosion prediction model is developed and applied to estimate the rate of erosion at a selected *** the predicted results have been compared with the observed data at the bend and all the available data at other bends along the Jamuna River.

关键词： Braided Jamuna River Bend Flow pattern Erosion prediction model

Computational Study on a Squid-Like Underwater Robot with Two Undulating Side Fins

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Journal of Bionic Engineering 2011年第1期8卷 25-32页

作者： md. Mahbubar rahman Yasuyuki Toda Hiroshi Miki Department of Naval Architecture and Ocean Engineering Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita City Osaka 565-0871 Japan

The undulating fin propulsion system is an instance of the bio-inspired propulsion systems. In the current study, the swimming motion of a squid-like robot with two undulating side fins, mimicking those of a Stingray or a Cuttlefish, was investigated through flow computation around the body. We used the finite analytic method for space discretization and Euler implicit scheme for time discretization along with the PISO algorithm for velocity pressure coupling. A body-fitted moving grid was generated using the Poisson equation at each time step. Based on the computed results, we discussed the features of the flow field and hydrodynamic forces acting on the body and fin. A simple relationship among the fin＇s principal dimensions was established. Numerical computation was done for various aspect ratios, fin angles and frequencies in order to validate the proposed relationship among principal dimensions. Subsequently, the relationship was examined base on the distribution of pressure difference between upper and lower surfaces and the distribution of the thrust force. In efficiency calculations, the undulating fins showed promising results. Finally, for the fin, the open characteristics from computed data showed satisfactory conformity with the experimental results.

关键词： biomimetics squid robot undulating fin propulsion efficiency hydrodynamics CFD

Efficient removal of heavy metals from electroplating wastewater using polymer ligands

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Frontiers of Environmental Science & Engineering 2016年第2期10卷 352-361页

作者： md. Lutfor rahman Shaheen M. SARKAR Mashitah Mohd YUSOFF Faculty of Industrial Sciences & Technology Universiti Malaysia Pahang 26300 Gambang Kuantan Malaysia

Poly（hydroxamic acid）-poly（amidoxime） che- lating ligands were synthesized from poly（methyl acrylate-co-acrylonitrile） grafted acacia cellulose for removing toxic metal ions from industrial wastewaters. These ligands showed higher adsorption capacity to copper （2.80 mmol. g-l） at pH 6. In addition, sorption capacities to other metal ions such as iron, zinc, chromium, and nickel were also found high at pH 6. The metal ions sorption rate （tl/2） was very fast. The rate of adsorption of copper, iron, zinc, chromium, nickel, cobalt, cadmium and lead were 4, 5, 7, 5, 5, 8, 9 and 11 min, respectively. Therefore, these ligands have an advantage to the metal ions removal using the column technique. We have successfully investigated the known concentration of metal ions using various parameters, which is essential for designing a fixed bed column with ligands. The wastewater from electroplating plants used in this study, having chromium, zinc, nickel, copper and iron, etc. For chromium wastewater, ICP analysis showed that the Cr removal was 99.8% and other metal ions such as Cu, Ni, Fe, Zn, Cd, Pb, Co and Mn removal were 94.7%, 99.2%, 99.9%, 99.9%, 99.5%, 99.9%, 95.6% and 97.6%, respectively. In case of cyanide wastewater, the metal removal, especially Ni and Zn removal were 96.5 and 95.2% at higher initial concentra- tion. For acid/alkali wastewater, metal ions removing for Cd, Cr and Fe were 99.2%, 99.5% and 99.9%, respectively. Overall, these ligands are useful for metal removal by column method from industrial wastewater especially plating wastewater.

关键词： heavy metals adsorption wastewater chelat-ing ligands plating industry

Cyclic liquefaction screening of sand with non-plastic fines:Critical state approach

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Geoscience Frontiers 2020年第2期11卷 429-438页

作者： md.Mizanur rahman TGSitharam Natural and Built Environments Research Centre(NBERC) School of Natural and Built EnvironmentsUniversity of South AustraliaMawson LakesSA 5095Australia Department of Civil Engineering Indian Institute of Science(IISc)BangaloreIndia

There have been significant advances in the application of critical state,CS,in liquefaction potential *** was done by comparing state parameter,j with estimated characteristic cyclic stress ratio,CSR due to an earthquake.A cyclic resistance ratio,CRR curve,which can be determined from cyclic liquefaction tests,separates historical liquefied and non-liquefied data points(j,CSR).On the other hand,the concepts of equivalent granular state parameter,j*,which was developed for sands with fines,can be used in lieu j to provide a unifying framework for characterizing the undrained response of sands with non/low plasticity fines,irrespective of fines content(fc).The present work combines these two propositions,and by merely substituting j*for j into the aforementioned CS approach to capture the influence of fc.A series of static and cyclic triaxial tests were conducted,separately and independently of the concept of j*,for sand with up to fc of 30%.The clean sand was collected from Sabarmati river belt at Ahmedabad city in India which was severely affected during the Bhuj earthquake,*** experimental data gave a single relation for CRR and j*which was then used to assess liquefaction potential for a SPT based case study,where fc varies along the *** prediction matched with the field observation.

关键词： Critical state State parameter Liquefaction Sands Fines Constitutive model

Infant and Under-five Mortality in Bangladesh: Discriminant Analysis

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Chinese Journal of Population,Resources and Environment 2010年第4期8卷 79-84页

作者： rahman md. Mahfuzar IsIam md. Rafiqul Population Science and Human Resource Development University of Rajshahi

Bangladesh is on target for achieving the Millennium Development Goal 4 relating to infant and under-five mortality because of very rapid reduction in mortality in recent years. But this rate of reduction may be difficult to sustain and may hamper the achievement of Millennium Development Goal 4. Therefore, the main objective of this paper is to discuss and compare the dif- ferent covariates of infant and under-five mortality in the context of overall country, urban and rural levels of Bangladesh using discriminant analysis. For this, the data are taken from Bangladesh Demographic and Health Survey, 2004. In discriminant analysis, the stepwise procedure has been picked up and only the significant variables are ranked according to the rank of Wilk's Lambda val- ues. The canonical discriminant function coefficients (unstandard- ized and standardized) for the predictor variables have also been calculated. Both the results show that breastfeeding is the most important variable in discriminating the two groups of mothers, i.e., mothers experiencing to infant mortality or not and mothers experiencing to under-five mortality or not. The related results of discriminant function also indicate that the discriminant func- tion is statistically significant and discriminates well. Therefore, improvements in the health system are essential for promoting the breastfeeding practices (both inclusive and exclusive), which may be the effective strategies to reach families and communities with targeted messages and information.

关键词： infant and under-five mortality breastfeeding prac- tices discriminant analysis

Nutrient dynamics associated with leaf litter decomposition of three agroforestry tree species (Azadirachta indica, Dalbergia sissoo, and Melia azedarach) of Bangladesh

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Journal of Forestry Research 2011年第4期22卷 577-582页

作者： Mahmood Hossain Mohammad Raqibul Hasan Siddique md. Saidur rahman md. Zaber Hossain md. Mahedi Hasan Forestry and Wood Technology Discipline Khulna University Khulna - 9208 Bangladesh Soil Science Discipline Khulna University Khulna-9208 Forestry and Wood Technology Discipline Khulna University Khulna- 9208

Azadirachta indica A. Juss, Dalbergia, sissoo Roxb., and Melia azedarach L. are little studied species in nutrient return capabilities from leaf litter decomposition to maintenance of the soil fertility despite their importance in agroforestry practices of Bangladesh. A leaf litter decomposition experiment was conducted using a litterbag teeh7 nique to assess the nutrient reaun efficiency of these species. The de- composition rate of leaf litter was highest for M. azedarach and lowest for D. sissoo. Rainfall and temperature of study sites showed a significant （p〈0.05） positive relationship with the rate of leaf litter decomposition. The highest decay constant was observed for M. azedarach （6.67）. Nitrogen and Phosphorus concentration in leaf litter showed a decreased trend sharply at the end of the first month, whereas rapid decrease of Potassium concentration was reported within 10 days. Conversely, higher concentration of nutrient was observed at the later stages of decomposition. All three species showed a similar pattern of nutrient release （K 〉 N 〉 P） during the decomposition process of leaf litter. Among the studied species, D. sissoo was best in terms of N and P return and A. indica was best in terms of K return.

关键词： agroforestry decay constant decomposition leaf litter andnutrient dynamics