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Subhasish Das ¹

Affiliations
1 Department of Geology and Geophysics IIT Kharagpur 721302, IN

Abstract

Analysis of ripple geometries using known tabulated laboratory and field data shows that the geometry can be of three types, i.e., sand ripples, light sediment ripples, and oscillatory bed ripples, reflecting different effects of the fluid shear stress and fluid accleration on the bed sediments. It is shown that when the bed shear stress or the amplitude of the water particle relative to the sediment size is small, the resulting vortices are more regular with low turbulence intensity and the generated ripples are two dimensional. However when the bed shear stress is large, the resulting vortices are very irregular with high turbulence intensity and the generated ripples are three dimensional in character.

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Subhasish Das ¹, Santansua Manta ¹

Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721 302, IN

Abstract

Critical studies of a part of Singhbhum basin around Bisrampur, Singhbhurn district, Bihar, show that the metasediments (considered to belong to the Dhanjori Group) lie unconformably above the Singhbhurn Granite. However a few tongues of the granite that occur within the metasediments have been explained as thrust slices of the basement within the cover rocks. Though three phases of deformation have been recorded here, and the general outcropgattern has been largely controlled by the second phase of deformation, there has not been any marked change in the spatial disposition of the coarser clastics. The shape of pebbles within the conglomerate, though often triaxial, cannot be correlated with the deformational history. This calts for original triaxiality of the pebbles. The high proportion of clastmatrix indicates that they were deposited under a two phase flow mechanism: a gravity mass flow aided by a high turbulent flow. Relatively high amounts of solid material in the fluid with variable particle size can create such a turbulent motion and the resultant scattered dispersion possibty accounts for the randomness in pebbleorientation. Accumulation of huge coarse clastics is, however, attributed to gravity mass flow. The general lack of turbidite structures in these litho-units can be attributed to flow inhomogeneity, flow velocity, nature of depositional substrate, relative significance of head-versus-body spilling from turbidity current. Presence of primary structures in arenaceous rocks and occurrence of these rocks as isolated bodies point to vigorous reworking and redeposition of the bottom sediments after cessation of the main flow. The huge pile of the rnicaceous phyllites probably represents relatively rapid deposition of silt grains from a highly concentrated mud-dominated turbidity current or very fluid silty debris flow deposited during the waning phase of turbidity flow. The entire load was deposited possibly over a shallow shelf edge. Retention of the original grain fabrics and the sedimentary structures in these metasediments, even though they are very close to a regionally developed shear zone, points to the existence of focally developed, sheltered low stress regimes provided by the Granite basement.

Keywords

Sedimentary Structures, Sedimentation, Dhanjori Group, Singhbhum, Bihar.

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Subhasish Das ¹

Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721 302, W.Bengal, IN

Abstract

The Proterozoic Chaibasa Formation belonging to the Singhbhum Group was deposited in small overlapping submarine fans along the eastern cratonic margin of an unstable foreland trough during the early phase of the Singhbhum Orogeny. The following features suggest deposition within the mid-fan complex: (I) a relatively high proportion of coarse, massive psammitic layers with small proportion of pelitic layers and classic graded sandstones; (2) the presence of shallow sand-filled channels; (3) the frequent associations of olistostromes; (4) association of thick coarse sandstone with thin layers of fine sandstone separated by thick shale units; (5) the presence of both positive and negative cycles in the stratigraphic record.

Sandstone bodies characteristic of the unchanneled fan lobes, represent deposition associated with basinward progradation of the lobe complex. Accumulation of a thick siltstone on top of the coarse sandstone facies during the active progradational phase is related to a channel cutoff in the upfan region. In contrast, the sandstone bodies present in the channel show an overall graded nature, lack thick siltstone horizon, contain erosional structures, and a higher percentage of positive cycles. The development of the submarine fan was related to external and internal factors, that is, the flow velocity, the rate of sediment supply coupled with channel migration, frequency of major storms or earthquakes to initiate submarine gravity flows. This development of alternating graded sandstone units and siltstone blankets may be a more useful criterion (than sedimentary structures) for the recognition of ancient mid-fan lobe sequences.

Keywords

Sedimentology, Chaibasa Formation, Singhbhum, Bihar.

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Subhasish Das ¹, Biswajit Majumder ¹, Arijit Chakraborty ¹, Bivas Mandal ¹, Pankaj Kr. Roy ¹, Asis Mazumdar ¹

Affiliations
1 Law and Management, Jadavpur University, Kolkata, West Bengal, IN

Abstract

Since the British period the Damodar River has been the main source of water supply in Raniganj, Asansol and Durgapur area of West Bengal State in India. Afterwards since nineties, the drinking water demand was increasing rapidly with the population rise. There has been a considerable scarcity in water supply especially in summer months. Recently, to augment the water supply situation, considering future demand and population rise, a hydro-geological study has been carried out during dry period at different locations on the river bed. The observation were undertaken in and around the existing pumping area on Damodar river located in the southern part of Raniganj. This research is aimed at assessing the yield test at exploratory bored wells to find out the minimum quantity of water available to design radial collector wells at three different locations with respect to their drawdown, transmissibility and storativity. Secondly, a field method for the mechanical analysis of bore well log material of the study area was attained to determine the material size and the required artificial gravel packing. On the basis of the field study and investigations, data collection, collasion and analysis, this paper has been prepared highlighting the characteristics of the aquifer, the location of the intake wells and yield of the bed.

Keywords

Damodar River, Aquifer, Bore Well, Yield Test, Drawdown, Transmissibility, Storativity, Sieve Analysis.

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Subhasish Das ¹, Pankaj Kumar Roy ¹, Asis Mazumdar ¹

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata, West Bengal, IN

Abstract

Management measure for Irrigation water by tidal back-water influx is an important issue for the sustainable living of rural communities in the areas where the rainfall is insufficient for rabi crop cultivation. Tidal back-water influx is one of the sources of irrigation water in the lower gangetic planes of West Bengal, India. Based on that concept, a plan is provided for the Magrahat basin of South 24 Parganas district in West Bengal for the augmentation of irrigation facilities through excess amount of tidal back-water entry during the post-monsoon period when the salinity of water is considerably low. In the present study, twenty major canals or khals of Magarahat basin are considered. Volume of available tidal water for irrigation of rabi crops was determined from the gauge data of tidal rivers. Here an attempt has been made to delineate not only the enhancement of the economic return of the people of the Magrahat basin but also to create provision for multi-cropping (rabi crops) pattern of agriculture/horticulture facilities during the dry season for sustaining of their livelihood. Also the tidal backwater surface profiles have been suggested for all the major canals of Magrahat basin using standard step method of gradually varied flow.

Keywords

Water Availability, Tidal Back-Water Influx, Gradually Varied Flow, Water Requirement of Crop, Water Distribution Management.

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Subhasish Das ¹, Ranajit Midya ¹, Buddhadeb Chatterjee ¹, Ranadeep Ghosh ¹, Rajib Das ¹, Asis Mazumdar ¹

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata–700032, West Bengal, IN

Abstract

The three-dimensional flow field at a flat plate (side facing the approaching flow) under clear water equilibrium scour regime was experimentally measured using an acoustic Doppler Velocimeter (ADV) in a laboratory tilting flume. Reynolds stresses at different azimuthal planes are computed. The bed shear stresses are determined from the Reynolds stresses and velocity gradients at different azimuthal planes (0°, i.e., at the upstream axis of symmetry, 45° and 90°). The critical bed shear stresses on the sloping beds are also computed with the help of Shields' diagram. The findings of the present study were also compared with the results obtained by previous researchers.

Keywords

Turbulent Flow, Threshold Condition, Clear Water Scour, Reynolds’ Stress.

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Subhasish Das ¹, Sandip Mukherjee ², Rakesh Kundu ², Pradip Bhattacharyya ³, Buddhadeb Duary ⁴, Satya Sundar Bhattacharya ⁵

Affiliations
1 Department of Environmental Science, Tezpur University, Tezpur 784 028,, IN
2 Department of Zoology, Visva Bharati, Santiniketan 731 235, IN
3 Indian Statistical Institute, North East Centre, Tezpur 784 028, IN
4 Palli Siksha Bhavana, Visva Bharati, Sriniketan 731 236, IN
5 Department of Environmental Science, Tezpur University, Tezpur 784 028, IN

Abstract

Agro-climatic factors largely regulate expression of phenolic compounds in plants. Carlinoside, a flavone glycoside, is known to eliminate bilirubin accumulation in rat liver. We cultivated Cajanus cajan uniformly in two different soil types - alluvial (AL) and laterite (LA). The climatic attributes and soil physicochemical properties of the two localities were significantly different from each other. Carlinoside, phenol and flavonoid concentrations were higher in plants grown in AL than in LA soils. We recorded higher UGT1A1 expression in liver hepatoma cell line HepG2 and rats treated with plant extracts from AL compared to LA.

Keywords

Cajanus cajan, Carlinoside, Plant Phenollics, Soil and Climate.

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Jayanta Phukan Dhekial ¹, Bhaskar Thakuria ¹, Swaroop Baruah Kumar ¹, Suman Talukdar ¹, Subhasish Das ¹

Affiliations
1 Dept. of Medicine, Gauhati Medical College and Hospital, Guwahati, Assam-32, IN

Abstract

Purpose: To collect hospital based data on the ever-increasing menace of household substance poisoning; so as to gauge the magnitude of the problem for formulating therapeutic and preventative strategies of the same. Method: Retrospective single center observational study for a period of one year. Results: Overall incidence was 3.2%; highest between 20 to 40 years. More incidences in the female sex were found in the rural population. Phenol and agricultural chemicals were mostly used. Familial disharmony and failure in examinations were the most common precipitating factors. Mortality rate was 1.2%. Conclusion: Knowledge for proper handling and first aid measures following exposure should be dissipated amongst the masses.

Keywords

Household Poisoning, Phenol, Familial Disharmony, Suicidal Ideation, Poisoning, Phenol Poisoning, Agricultural Poisoning.

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Subhasish Das ¹, Subhasish Das ²

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata and Assistant Engineer, Kolkata Municipal Corporation, IN
2 School of Water Resources Engineering, Jadavpur University, Kolkata, IN

Abstract

Energy plays a key role in all organizations, particularly those that are energy intensive. A comprehensive study to establish and investigate, energy balances for a specific plant unit has been conducted. In this study electrical energy assessment of a water treatment plant has been successfully completed. Jai Hind Jal Prakalpa water treatment plant located at Dhapa, Kolkata in India was selected for this study. From the energy point of view there is a financial loss in the monthly electricity bill of the plant and this may be rectified if suitable steps are taken. It is observed that by proper utilization of electricity, approximately 11.5% of electricity charges may be saved which amount approximately rupees four lakh per month.

Keywords

Water Treatment Plant, Energy Consumption, Energy Conservation.

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Subhasish Das ¹, Mahendra Kumar Sahu ²

Affiliations
1 GIMS, Gunupur, Odisha, IN
2 GIMS, Gandhi Group of Institutions, Gunupur, Odisha, IN

Abstract

The prime goal of the study is to understand the concept of entrepreneurial orientation (EO) of the technical institutions in Odisha. Further, this study tries to measure and validate the scale of EO developed by Miller, Covin, & Slevin (1989). Data from 397 respondents, who are basically the employees of the technical institutions, are collected to test the convergent and discriminant validity of the scale. In order to develop a measurement model, an exploratory factor analysis, followed by a confirmatory factor analysis, is deployed. The scale is found to have strong construct validity and the measurement model of the three underlying constructs – innovativeness, proactiveness and risk-taking developed by Miller, Covin, & Slevin (1989) – shows a good model fit.

Keywords

Entrepreneurial Orientation, Exploratory and Confirmatory Factor Analyses, Scale Validation.

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Biprodip Mukherjee ¹, Asim Kuila ¹, Subhasish Das ¹

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata, IN

Abstract

Directly drinkable water supplied to the inhabitants of any rural zone is met for the most part from the groundwater sources. A large number ofthe tubewells end up dry amid summer causing genuine water emergency. The Public Health Engineering Directorate (PHED) under Government of West Bengal decided to execute a scheme for withdrawing and delivering surface water from River Rupnarayan to supply drinkable water to the residents of Panskura- II block of East Medinipur district in West Bengal. In this study a command area zone of close piped network from the above mentioned scheme has been chosen. During the analysis, WaterGEMS software was used. The entire network system consists about 341 numbers of pipes and 289 numbers of junctions. The study is concentrated to develop a model of pipe network of Zone I of Panskura Block II under PHED water supply scheme based on WaterGEMS software, to determine the velocity and headlosses in pipes alongwith pressure at nodes in modeled system and to optimize the number and locations of airvalves in order to exhaust away the entrapped air in the pipelines due to geographical undulations. About twelve optimized air valves were suggested for the whole network.

Keywords

Air Valves, Losses in Pipelines, Accuracy, WaterGEMS, Pressure, Undulations.

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Souvik Chakraborty ¹, Subhasish Das ²

Affiliations
1 School of Water Resources Engineering, Jadavpur University and Department of Civil Engineering, Dr. Sudhir Chandra Sur Degree Engineering College, Kolkata, West Bengal, India., IN
2 School of Water Resources Engineering, Jadavpur University, Kolkata, West Bengal, IN

Abstract

Contai, a district of Purba Medinipur, has 79 natural reservoirs of minimum 0.01 hectare capacity. This water is utilised for irrigation and industrial purpose. The population of Contaihas been increased around 19% in last census decade. The decadal growth of population density in Contai is high compared to West Bengal. It had been also found that the perimeter and area of the water surface of these reservoirs were reducing gradually in last decade. Now with increasing population - irrigation and industrialisation has been taken place in Contai manifold. So withdrawal of water from the 79 existing reservoirs of Contai has been taken places in indiscriminate ways. But the recharge of reservoirs is very low since amount of rainfall in whole Purba Medinipur is quite less. In most of the season in 2019 here rainfall is less than 100 mm. From the present study it has been observed that annually the perimeter and surface area of such reservoirs are decreasing around 2.5% and 1.1% respectively. So abstraction is more than recharge of reservoirs. It's a little worried situation for Contai. If such an indiscriminate usage of water from reservoir for increasing irrigation and industrialisation has been taken place then reservoirs will become dry. Since rivers and canals in Purba Medinipur are almost saline prone so no alternative way of getting water for irrigation and industrialisation will be available. So it's high time to conserve the reservoirs of Contai. If irrigation and industrialisation are taking place by the withdrawal of groundwater then groundwater level will be diminished fast. According to Gyben Herzberg principle, for a half metre decline in groundwater level seawater encroaches into the mainland by 20 metres. So if water harvesting can be adapted to store water in reservoirs to supply water for irrigation and industrialisation then that can be bene!tted. The usage of water for various units from these reservoirs can also be limited.

Keywords

Reservoir, Perimeter, Area, Irrigation, Population, Industrialization.

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Prabir Kumar Maity ¹, Subhasish Das ¹, Rajib Das ¹

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata 700032, West Bengal, IN

Abstract

There is a severe warning of groundwater pollution in the coastal district of Purba Medinipur, West Bengal. This is due to ingression of saline water intrusion. A top stratum of the soil in coastal area of the district is found to be made of different layer of clay and sand of sea origin. The groundwater cannot be used for domestic, irrigation or industrial purposes. As a result of continuous extraction of water, the groundwater is formed like a cone of depression. It has resulted in redundant well and therefore the water extraction has become uneconomical due to augmented lift. All these necessitate for urgent measures to control the ingression of salt water into the coastal aquifers. Some measures to control the encroachment of salt water are suggested in this paper.

Keywords

Inshore Geological Stratum, Chemical Analysis, Salt Water Ingression, Controlling Methods, Aquifer Improvement Plan.

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Plaban Sen ¹, Biprodip Mukherjee ¹, Subhasish Das ¹

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata, IN

Abstract

Process pipeline system designs are governed by Industrial or International Codes and Standards to transport the fluid, steam or air through the employed pipe system in plants of many industries. Such piping arrangements consist of components like pipes, different valves, flanges, different fittings, varying elbows, different gaskets, and further specialties. The code AS ME B31.3 for process design piping has been used throughout this study. This code is applied in refineries of petroleum, oil and gas industries, chemical plants, textile plants, semi-conductor plants, paper mills, and many other industrial plants. Here the objective is to clearly explain the flexibility characteristics, elemental forces and displacements and also the stress analysis that have been kept in agreeable limits as per typical standards for major load conditions like hydrostatic - HYD, sustained - SUS, operating - OPE and experimental - EXP cases. The study was conducted on nitrogen pipeline network of a process plant at Durgapur, West Bengal in India.

Keywords

Process Pipelines, Piping Support, Loading Conditions, Stresses, Deflections.

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Asim Kuila ¹, Biprodip Mukherjee ¹, Subhasish Das ¹, Asis Mazumdar ¹

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata, IN

Abstract

A laboratory experiment was conducted by placing a 50 mm diameter horizontal cylinder across the flow and a 50 mm wide vertical plate at 55 mm downstream of it in a flume to observe and compare the surrounding flow fields past these structures. The cylinder vertical position was altered from 0.3 to 0.4 times of flow depth of water. Around these structures, the obtained flow fields, vortex formation, and turbulent characteristics are analyzed, compared and discussed.

Keywords

Submerged Cylinder, Vortex-Induced Vibration, Vortices, Flow Fields.

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Saikat Mondal ¹, Sanchayan Mukherjee ², Subhasish Das ¹

Affiliations
1 School of Water Resources Engineering, Jadavpur University, Kolkata-700032, IN
2 Department of Mechanical Engineering, Kalyani Government Engineering College, Kalyani-741235, IN

Abstract

Oscillating hydraulic jump experiments were conducted by increasing the temperature of water from minimum to maximum within a range of measurement. By varying temperature from 32-40°C, different jump characteristics were observed and noted. The varying temperature was measured throughout the jump profiles and dependence of jump parameters with varying temperature is measured and quantified. This study may find applications where a changing stream water temperature significantly affects the jump characteristics.

Keywords

Rapidly Varied Flow; Subcritical Flow; Supercritical Flow; Froude Number; Sequent Depth Ratio.

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Souvik Chakraborty ¹, Subhasish Das ²

Affiliations
1 Dr. Sudhir Chandra Sur Institute of Technology & Sports Complex, Kolkata 700074, West Bengal, IN
2 School of Water Resources Engineering, Jadavpur University, Kolkata 700032, West Bengal, IN

Abstract

Arsenic found in contaminated saltwater has very serious side effects. Purba Medinipur was free of arsenic until 2009. Present study verifies whether the coastal areas of Purba Medinipur, after 2009, were arsenic contaminated. From Contai, Digha, and Egra regions, 97 bore wells were selected to collect groundwater samples and analyze arsenic contamination. Few areas have shown the presence of arsenic in groundwater. However, the concentration in many areas is found to be below the permissible limit of drinking water.

Keywords

Arsenic Contamination, Seawater Intrusion, Groundwater Declining.

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