Flexural deformation controls on Late Quaternary sediment dispersal in the Garo-Rajmahal Gap,NW Bengal Basin     

Jean-Louis Grimaud  Celine Grall  Steven Goodbred  Michael S. Steckler  Ryan Sincavage  Jennifer L. Pickering  Chris Paola  Leonardo Seeber  Md. Saddam Hossain 《Basin Research》2020,32(5):1242-1260

Subsurface deformation is a driver for river path selection when deformation rates become comparable to the autogenic mobility rate of rivers. Here we combine geomorphology, soil and sediment facies analyses, and geophysical data of the Late Quaternary sediments of the central Garo-Rajmahal Gap in Northwest Bengal to link subsurface deformation with surface processes. We show variable sedimentation characteristics, from slow rates (<0.8 mm/year) in the Tista megafan at the foot of the Himalaya to nondeposition at the exposed surface of the Barind Tract to the south, enabling the development of mature soils. Combined subsidence in the Tista fan and uplift of the Barind Tract are consistent with a N-S flexural response of the Indian plate to loading of the Himalaya Mountains given a low value of elastic thickness (15–25 km). Provenance analysis based on bulk strontium concentration suggests a dispersal of sediment consistent with this flexural deformation—in particular the abandonment of the Barind Tract by a Pleistocene Brahmaputra River and the current extents of the Tista megafan lobes. Overall, these results highlight the control by deeply rooted deformation patterns on the routing of sediment by large rivers in foreland settings.  相似文献   

The skin friction in the unsteady free-convection flow past an accelerated plate     

M. A. Hossain  L. K. Shayo 《Astrophysics and Space Science》1986,125(2):315-324

In this paper the unsteady laminar free-convection flow of a viscous incompressible fluid, past an accelerated infinite vertical porous plate subjected to a constant suction (or injection) in considered. Numerical results for the skin-friction on the plate are obtained for the class of accelerated motions whose velocity is of the formU ₀ t ⁿ wheret is time,U ₀ a constant, andn is a positive integer. The skin friction tends to zero with increasingt when the Grashof number Gr=², the Prandtl number =1,n=0, and >0 which corresponds to suction.On leave of absence from the Department of Mathematics, University of Dhaka, Bangladesh.On leave from absence from the Department of Mathematics, University of Dar-es-Salaam, Tanzania.  相似文献   

Slow arsenic poisoning of the contaminated groundwater users     

M. M. Uddin  A. K. M. Harun-Ar-Rashid  S. M. Hossain  M. A. Hafiz  K. Nahar  S. H. Mubin 《International Journal of Environmental Science and Technology》2006,3(4):447-453

This paper gives impact of Arsenic contaminated water on human health as well as overview of the extent and severity of groundwater arsenic contamination in Bangladesh. Scalp hair is the most important part of the human body to monitor the accumulation of this type of poison. Therefore, an experiment has been carried out by Neutron Activation Analysis (NAA) at Atomic Energy Research Establishment (AERE), Savar, Dhaka, Bangladesh on human hair of corresponding tube well water users of these areas to determine the total accumulation of arsenic to their body. Hair samples collected from the region where the groundwater was found highly contaminated with arsenic. The obtained results of arsenic concentration in the lower age (Hb) categories of users (below 12 years of age users) is in the range of 0.33 to 3.29 /gmg/g (ppm) and that in the Hu categories (upper 12 years of age users) is 0.47 to 6.64 μg/g (ppm). Where as maximum permissible range is 1 ppm certified from WHO. Results show that the peoples are highly affected where the groundwater is highly contaminated with arsenic and acts as the primary source of arsenic poisoning among the peoples of those areas. The results indicate that human population is affected with arsenic locally using the contaminated water for a long time.  相似文献   

Towards Formulation of a Space-borne System for Early Warning of Floods: Can Cost-Effectiveness Outweigh Prediction Uncertainty?     

Faisal Hossain 《Natural Hazards》2006,37(3):263-276

The three most important components necessary for functioning of an operational flood warning system are: (1) a rainfall measuring system; (2) a soil moisture updating system; and, (3) a surface discharge measuring system. Although surface based networks for these systems can be largely inadequate in many parts of the world, this inadequacy particularly affects the tropics, which are most vulnerable to flooding hazards. Furthermore, the tropical regions comprise developing countries lacking the financial resources for such surface-based monitoring. The heritage of research conducted on evaluating the potential for measuring discharge from space has now morphed into an agenda for a mission dedicated to space-based surface discharge measurements. This mission juxtaposed with two other upcoming space-based missions: (1) for rainfall measurement (Global Precipitation Measurement, GPM), and (2) soil moisture measurement (Hydrosphere State, HYDROS), bears promise for designing a fully space-borne system for early warning of floods. Such a system, if operational, stands to offer tremendous socio-economic benefit to many flood-prone developing nations of the tropical world. However, there are two competing aspects that need careful assessment to justify the viability of such a system: (1) cost-effectiveness due to surface data scarcity; and (2) flood prediction uncertainty due to uncertainty in the remote sensing measurements. This paper presents the flood hazard mitigation opportunities offered by the assimilation of the three proposed space missions within the context of these two competing aspects. The discussion is cast from the perspective of current understanding of the prediction uncertainties associated with space-based flood prediction. A conceptual framework for a fully space-borne system for early-warning of floods is proposed. The need for retrospective validation of such a system on historical data comprising floods and its associated socio-economic impact is stressed. This proposal for a fully space-borne system, if pursued through wide interdisciplinary effort as recommended herein, promises to enhance the utility of the three space missions more than what their individual agenda can be expected to offer.  相似文献   

Assessing geo-mechanical and leaching behavior of cement–silica-fume-stabilized heavy metal-contaminated clayey soil     

Amir Reza Goodarzi  Mohammad Hossain Zandi 《Environmental Earth Sciences》2016,75(10):911

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Long-term seasonal rainfall forecasting: efficiency of linear modelling technique     

Iqbal Hossain  H. M. Rasel  Monzur Alam Imteaz  Fatemeh Mekanik 《Environmental Earth Sciences》2018,77(7):280

Using the lagged (past) climate indices, including El Nino–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) as input parameters and long-term spring rainfall as outputs, calibration and validation of the linear multiple regression (MR) models have been performed. Since Australian rainfall varies both temporally and spatially, the analysis on the linear MR models was performed on regional scale. These models show the capability of linear MR technique for long-term predictions of Western Australian spring rainfall. The emphasis was given to assess the statistical correlations between Western Australian spring rainfall and dominating large-scale climate modes. The efficiency of linear modelling technique was evaluated to predict seasonal rainfall forecasting. At the same time, the Pearson correlation (R), mean absolute error, root-mean-square error and Willmott index agreement (d) were used to assess the capability of MR models. The models which fulfilled the limits of statistical significances were used for the prediction of future spring rainfall using independent data set. The results indicate that during calibration periods maximum achievable correlations varied from 0.47 to 0.53 for the selected stations. In regard to predict peaks and troughs of rainfall time series, it was found that correlations between predicted and actual peaks varied from 0.82 to 0.94 and between predicted and actual troughs varied from 0.53 to 0.91.  相似文献   

Geology and Active Tectonics of the Lalmai Hills,Bangladesh–An Overview from Chittagong Tripura Fold Belt Perspective     

Md. Sharif Hossain Khan  Md. Sakawat Hossain  Md. Azim Uddin 《Journal of the Geological Society of India》2018,92(6):713-720

The Lalmai Hills is a low amplitude anticline with significant variations in landforms, situated along the western fringe of the Chittagong-Tripura Fold Belt (CTFB) and immediate east of the Indo-Burmese deformation front. This fold belt of the Bengal Basin along with more easterly Indo-Burman Range (IBR) developed as a consequence of the oblique collision between Indian and Burmese plates. This neotectonic activity is still continuing and shaping the geomorphology of the area. This study is conducted based on the geomorphological observation of the topo maps and satellite images, and through reconnaissance field work. Stream length gradient index (SL Index) and Mountain front sinuosity (S_mf) reveals the relative status of tectonic activity. Anomalous SL index values confirm the position of the sympathetic minor faults and also relate to the local stratigraphy. A 2D structural model based on the seismic section reveals thrusts controlled wedge-shape upliftment of the central part as pop-up anticlinal structure. The western thrust is the direct result of the collision of the Indian and Burmese plates, and the eastern one is the back thrust of the western fault. Low S_mf value found in the western flank signifies recent tectonics and relatively high S_mf value in the eastern flank indicates that weathering intensity is relatively greater compared to western flank. Finally, the findings not only enhanced the understanding of geomorphic evolution and active tectonics of the Lalmai Hills area but also the overall tectonic and geomorphic evolution of the western most folded part of the CTFB.  相似文献   

Rice research for food security and sustainable agricultural development in Asia: Achievements and future challenges   总被引：1，自引：0，他引：1  

M. Hossain  K. S. Fischer 《GeoJournal》1995,35(3):286-298

Rice is the major staple food of Asia, and an important source of employment and income in rural areas, particularly in low-income countries. Research has contributed significantly in achieving food security by increasing the yield potential of rice in irrigated systems, reducing the crop maturity period and achieving yield stability by developing resistance against major insects and diseases in the modern high-yielding varieties. Poverty is, however, still extensive in fragile rainfed rice ecosystems where rice yield has remained low, as scientists have yet to develop high-yielding varieties resistant to abiotic stresses and problem soils. Rice production needs to be increased by another 70% over the next 30 years to meet growing food needs. This has to be achieved with less land, less water, and less labor to accommodate the demand for these inputs from the expanding nonagricultural sectors. The challenge to the rice research community is to make further shifts in yield potential of rice for the irrigated systems, to close the yield gaps in the rainfed systems through developing resistance of high yielding varieties to abiotic stresses, and greater understanding of the interactions between genotypes and environment, developing durable resistance against pests and diseases to reduce farmers' dependence on harmful agrochemicals, and to increase efficiency in the use of water, labor and fertilizers. As further intensification of rice cultivation is inevitable, scientists must understand the negative environmental side-effects of increasing rice productivity, to develop appropriate mitigation options.  相似文献   

Determination of strain from stretched belemnites     

Khandeker Mosharraf Hossain 《Tectonophysics》1979,60(3-4):279-288

Belemnites are valuable strain markers and can be used to determine the elongation that has been suffered by the matrix in which they are situated. Experiments simulating the development of stretched belemnites have been performed to verify their deformation history. The analysis of the experimental results is used in the interpretation of field examples collected from Leytron, Valais, Switzerland. The amount of strain suffered by Leytron belemnites has been evaluated using the “least square” method and the result has been compared with that obtained by the “average elongation” method. The relationship between the final orientation of the whole specimen (θ′_b) and that of the fragments (θ′_f) demonstrates that the Leytron belemnites have suffered an irrotational type of deformation.  相似文献   

Oblique propagation of ion acoustic shock waves in weakly and highly relativistic plasmas with nonthermal electrons and positrons     

M. G. Hafez  N. C. Roy  M. R. Talukder  M. Hossain Ali 《Astrophysics and Space Science》2016,361(9):312

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