Papers by SAYANTAN GANGULY
ABSTRACT Aquifer thermal energy storage system (ATES) for long term storing of excess thermal ene... more ABSTRACT Aquifer thermal energy storage system (ATES) for long term storing of excess thermal energy for future use is under research focus for quite some time. The present study is concerned about presenting a one dimensional numerical model of such a system with a porous aquifer with block heterogeneities, where hot water in injected through a single injection well into the porous aquifer and the movement of the hot water thermal front generated due to the injection is investigated. The numerical modeling is performed using multiphysics software COMSOL. The model is developed first for the general case considering convective and conductive modes of heat transport and a time varying pulse type injection rate and then for simpler case considering injection rate constant. Results for another simple model for a homogeneous aquifer are also presented in order to compare and validate it with an analytical model derived here. Assessment of the influence of some parameters involved in the heat transport phenomenon in porous media is performed at last.
Lowland Technology International, 2015
Over last few decades the Punjab region of India has been one of the country's leading contri... more Over last few decades the Punjab region of India has been one of the country's leading contributors to agricultural products. The agricultural farms in the region are supplied with water from a well-established canal system and groundwater reserve in the state. The share of irrigated area in the region fed by canals and groundwater wells are 28 and 72%, respectively. The over and unscientific usage of groundwater over the years has resulted in groundwater depletion at an alarming rate. To help policymakers address the situation and develop effective plans, forecasting groundwater recharge for the future is utmost essential. The recharge process primarily governs the growth or depletion of groundwater reserve. Groundwater recharge is one of the most difficult phenomena to be quantified as it cannot be measured directly and is influenced by several processes varying spatially and temporally. Extensive research work for quantifying the groundwater recharge have been performed in th...
Chromium (VI) [Cr(VI)] is abundantly used for several industrial applications especially in stain... more Chromium (VI) [Cr(VI)] is abundantly used for several industrial applications especially in stainless steel production and as an anti-corrosive agent in ceramics, textile industries and tanneries. Despite its versatile uses, Cr (VI) is a major environmental threat and is a known carcinogen. Therefore, proper precaution must be implemented while working with Cr (VI) or while disposing it after use. Due to improper handling and lack of proper care, Cr(VI) is still found in industrial wastewaters or landfill sites. The Cr(VI) in landfills can leach into the ground during rainfall and can risk the contamination of the groundwater causing a health catastrophe when consumed. This study focuses on effective Cr(VI) remediation by the process of adsorption. Magnetite particles synthesized by co-precipitation method at various temperatures (room temperature of 25οC, 60οC and 90οC) are used as an absorbent for achieving maximum removal efficiency of Cr(VI) from water. An initial concentration ...
New Journal of Chemistry
One NiII2MnII3 and two CuII2MnII3 complexes have been synthesized using N2O2 donor ligands. The f... more One NiII2MnII3 and two CuII2MnII3 complexes have been synthesized using N2O2 donor ligands. The former complex exhibits spin crossover at 2 K temperature. All the complexes exhibit catecholase-like activities.
2017 8th IEEE Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON), 2017
Abnormalities in the vascular structure of a retina, such as abnormal changes in thickness of ves... more Abnormalities in the vascular structure of a retina, such as abnormal changes in thickness of vessel, tortuosity, or the appearance of retinal lesions, may be associated with the occurrence of retinopathy diseases. An automated structural analysis of changes in vessel morphology may help indicating the clinical signs of retinopathies, describing their early occurrence or severity. We propose a framework consisting of a set of methods for automated characterization of the retinal vessel structure with respect to its morphological properties in two-dimensional fundus images comprising of segmented vascular networks. The methods are validated with the manually annotated retinal fundus images as a ground truth.
<p>Chromium (VI) is a known toxin and carcinogen which is still abundantly ... more <p>Chromium (VI) is a known toxin and carcinogen which is still abundantly used in various industries primarily as an anti-corrosive agent. Thus in case of accidental spillage of it, without proper treatment and disposal, it might leach into the ground and pollute the soil and the groundwater table. The reactivity and solubility of Cr(VI) is extremely high in water making it more dangerous if consumed. The transport and fate of a contaminant in sub-surface porous media is governed by the processes of advection, dispersion and sorption. The transport of Cr (VI) is highly influenced by the processes of adsorption and desorption. The soil sediments have different physical and chemical properties which affect their adsorption efficiencies to a large extent. Hence, the knowledge of adsorptive capacities of the soil sediments is necessary to determine the time of travel of the contaminant plume in the porous media. The present study is conducted to determine the adsorption efficiency of natural soil if Cr(VI) gets accidentally leaked from a stainless steel manufacturing plant located in Rupnagar district of Punjab, India. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were performed to assess the surface morphology and chemical composition of the soil layers located above the local water table. The initial concentration of Cr(VI) was taken to be 2 mg/l to conduct the batch adsorption studies. The optimum values of parameters like: dose of soil, change of pH of the solution, the time of contact between the adsorbate and the adsorbent and concentration of metal ion adsorbed, are determined in the study. Langmuir, Freundlich and BET adsorption isotherms along with kinetic models were also examined to investigate the mechanisms of adsorption.</p><p><strong>Keywords:</strong> Chromium (VI); Adsorption; Natural attenuation; Batch adsorption studies; Adsorption isotherms; Kinetic models.</p>
<p>Groundwater is an important resource in India as it is used extensively ... more <p>Groundwater is an important resource in India as it is used extensively for industrial, agricultural and drinking purposes<strong>. </strong>With the increase in demand due to growth in population, industrialization and improvement of living standards, the groundwater resources in India are depleting. For instance, the long-term trend of groundwater level observed in the Ropar district of Punjab, India for a span of ten years shows a gradual decline. The maximum fall of groundwater level is observed to be 1.05 m/year. In Ropar, the natural recharge process is diminishing because of rapid urbanization, variation in rainfall, and temperature patterns. Therefore the available water is found to be insufficient to fulfil the rise in water demand.To replenish the declining groundwater table and thus maintain the balance between the water supply and demand, artificial recharge techniques are proven to be beneficial in various studies. In this study, areas suitable for artificial recharge have been proposed.Remote Sensing(RS) techniques and the Geographic Information System(GIS) has been used to prepare various thematic maps constituting slope, land use & land cover, soil, geomorphology, the thickness of granular zone (permeable zones), the distance between recharge structure and the Sutlej river, rainfall map, drainage density, and population density. Lithological mapping in and around the Ropar district has been analyzed using borehole logs and reports from Central Ground Water Board, Govt. of India. Analytical Hierarchical Process (AHP) and Artificial Neural Networks (ANN) model have been used to determine the weightage of different parameters to map the suitable areas required for artificial recharge in the Ropar District. Finally, the best type of artificial recharge structure has been chosen based on higher stream order, drainage density and lithology for the present scenario.</p>
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
This paper presents experimental performance data of a total flow combined desalination and power... more This paper presents experimental performance data of a total flow combined desalination and power generation system. A twophase flow simple reaction turbine has been used in this system which operates on the trilateral flash cycle. Hot saline water is used as the working fluid. The hot water supply temperature is varied from 80oC to 95oC, while the condenser is maintained at about 35oC to 45oC. This paper examines the concept of using the trilateral flash cycle for combined desalination and power generation from saline water in the salt affected areas using geothermal energy. The basic working principle of the combined desalination and power generation system is presented followed by discussions of the governing equations and the thermodynamics of the proposed system. Experimental setup and the test results are briefly explained to give an idea of the performance of the proposed system in a laboratory scale. Later it is shown how a combined desalination and power generation system c...
Energies, 2018
An exact integral solution for transient temperature distribution, due to injection-production, i... more An exact integral solution for transient temperature distribution, due to injection-production, in a heterogeneous porous confined geothermal reservoir, is presented in this paper. The heat transport processes taken into account are advection, longitudinal conduction and conduction to the confining rock layers due to the vertical temperature gradient. A quasi 2D heat transport equation in a semi-infinite porous media is solved using the Laplace transform. The internal heterogeneity of the geothermal reservoir is expressed by spatial variation of the flow velocity and the effective thermal conductivity of the medium. The model results predict the transient temperature distribution and thermal-front movement in a geothermal reservoir and the confining rocks. Another transient solution is also derived, assuming that longitudinal conduction in the geothermal aquifer is negligible. Steady-state solutions are presented, which determine the maximum penetration of the cold water thermal fro...
New Journal of Chemistry, 2019
Three new one-dimensional CoII/CoIII chains have been synthesized using N-salicylidene-l-alanine/... more Three new one-dimensional CoII/CoIII chains have been synthesized using N-salicylidene-l-alanine/N-salicylidene-l-phenylalanine and 2,2′-bipyridine/1,10-phenanthroline. All three complexes exhibit phenoxazinone synthase-like activity.
Inorganica Chimica Acta, 2019
Tri-nuclear copper-cadmium complexes of a N 2 O 2-donor ligand with the variation of counter anio... more Tri-nuclear copper-cadmium complexes of a N 2 O 2-donor ligand with the variation of counter anions: Structural elucidation and theoretical study on intermolecular interactions, Inorganica Chimica Acta (2019), doi:
Energy, 2019
In salinity gradient solar ponds (SGSPs) solar thermal energy is mainly stored in the lower-conve... more In salinity gradient solar ponds (SGSPs) solar thermal energy is mainly stored in the lower-convective zone (LCZ) the volume of which defines the thermal mass of storage. The present study explores the provision of increasing the heat storage in a SGSP by increasing the thermal mass of it. It also addresses the method of enhancing the thermal performance of a SGSP by increasing the thermal mass, while adding heat from external sources. Earlier studies have proved that adding external heat to the SGSP for storage enhances the thermal performance of it significantly. This study aims to prove that increasing the thermal mass of storage further increases the energy efficiency of a SGSP when external heat is added to it. A hybrid system of a SGSP coupled with evacuated tube solar collectors (ETSCs) is used in this study. Several parameters like storage temperature in LCZ, heat addition flux and heat addition efficiency of ETSC, instantaneous efficiency of SGSP, heat extraction from SGSP are studied in this paper for different cases of with and without heat addition and with normal and enhanced thermal mass. It is found that increasing thermal mass can significantly enhance the thermal performance and efficiency of a SGSP.
Journal of Solar Energy Engineering, 2018
This technical brief presents a study on the effectiveness of the bottom insulation of a salinity... more This technical brief presents a study on the effectiveness of the bottom insulation of a salinity gradient solar pond (SGSP) in Melbourne, Australia. Insulation is applied at the bottom of a SGSP in order to minimize the heat loss from the SGSP to the ground underneath. But selection of optimum thickness of the insulation to extract the best thermal performance of an SGSP is a challenge as insulation involves significant investment. Hence, modeling heat loss from SGSP to the ground before and after applying the insulation is thus very essential. In this study, a layer of polystyrene is used as insulation at the bottom of SGSP. The temperature distribution in the SGSP and ground below it, the efficiency of the SGSP and the heat removal from SGSP are estimated for the SGSP without insulation and with insulation of different thicknesses. The results show that the insulation definitely reduces the heat loss from the SGSP to the ground, but to a certain extent. Insulation beyond a certai...
New Journal of Chemistry, 2018
A one-dimensional mixed-valence MnII/MnIII chain has been synthesized using N-salicylidene-l-alan... more A one-dimensional mixed-valence MnII/MnIII chain has been synthesized using N-salicylidene-l-alanine and 2,2′-bipyridine. The complex shows moderate catecholase and phenoxazinone synthase-like activity.
ACS applied materials & interfaces, Jan 16, 2018
Herein we have engineered a smart nuclear targeting thiol-modified riboflavin-gold nano assembly,... more Herein we have engineered a smart nuclear targeting thiol-modified riboflavin-gold nano assembly, RfS@AuNPs, which accumulates selectively in nucleus without any nuclear-targeting peptides (NLS/RGD) and shows photophysically in vitro DNA intercalation. A theoretical model using Molecular Dynamics has been developed to probe the mechanism of formation and stability as well as dynamics of the RfS@AuNPs in aqueous solution and within DNA microenvironment. The RfS@AuNPs facilitate the binucleated cell formation that is reflected in the significant increase of DNA damage marker, γ-H2AX as well as the arrest of most of the HeLa cells at pre-G1 phase indicating cell death. Moreover, a significant upregulation of apoptotic markers confirms that the cell death occurs through apoptotic pathway. Analyses of the microarray gene expression of RfS@AuNPs treated HeLa cells show significant alterations in vital biological processes necessary for cell survival. Taken together, our study reports a un...
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Papers by SAYANTAN GANGULY