Browsing by Author "Tapas Das"

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Advances in Semiconducting Fibers
(CRC Press, 2024) Sanjeev Verma; Tapas Das; Shivani Verma; Ram K. Gupta; Bhawna Verma
The development of semiconductor fiber technology in recent years has been accelerated by improvements in fabrication and post-processing methods. Numerous opportunities, including solar energy harvesting, photodetection, signal modulation, and in-fiber frequency generation, have been made possible by combining the electronic and optical functions of fiber-structured semiconductor materials. An outline of the most recent developments in semiconductor material fibers, such as manufacturing and after-processing techniques, optical characteristics and different materials, is provided in this chapter. Applications for lasers, multimaterial functional fibers, optical–electrical conversion and nonlinear optics are also presented. © 2025 selection and editorial matter, Ram K. Gupta; individual chapters, the contributors.
Assessing urban landscape dynamics and its relations to changing surface thermal character and prospects: a geospatial study of a tropical industrial city using machine learning algorithms
(Springer, 2025) Sribas Patra; Kapil Kumar Gavsker; Tapas Das
Machine learning (ML) models are leading analytical techniques that provide insights into exploring urban landscape dynamics over time. The ML at present plays a crucial role in comprehending city growth and directing spatial processes of urban planning. The present study investigates the influences of LULC dynamics in the context of urban thermal variations based on modeling future land surface temperature (LST), particularly during summer and winter seasons, using advanced ML algorithms and earth observation satellite images (Landsat 8 and Landsat 5). The study shows that the built-up area in Durgapur Municipal Corporation (DMC) has increased by 39% during 1991–2021 by contracting agricultural land (32.20 km2) which is followed by green space (16.36 km2) and barren land (9.56 km2). The succeeding growth of seasonal LST (increase of about 0.23 °C and 0.17 °C in mean LST during summer and winter season, respectively) over DMC indicated that a warming trend of urbanization on the surface was reported during 1991–2021.The rapid urban expansion and landscape spatial heterogeneity in the study area significantly affect urban land surface temperature. The biophysical aspects are analyzed and explained in the study area to uncover the nature of urbanization in tropical areas. Due to high heat capacity, evaporative and rising latent heat flux of the study area, the urban water bodies and vegetation have a moderate effect on the urban heat island phenomenon. As a result, an increase in urban green space and avoidance of non-impermeable surface seems to be prospective strategies to minimize the adverse impacts of ULST. Therefore, further research findings would assist scholars, legislators, and urban planners in redirecting and further developing sustainable measures for mitigating detrimental effects of urban heat island. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Bioremediation of textile wastewater using Bacillus cereus isolated from refinery site: Comparative analysis of free and immobilized cells systems
(Elsevier B.V., 2024) Ganesh Swain; Yash Srivastava; Tapas Das; Ravi Kumar
The textile industries consume a considerable amount of freshwater and discharge untreated or semi-treated pollutants to the environment. Azo dyes, generally employed in textile manufacturing industries, have a hazardous impact on the ecosystem. Incomplete treatment of wastewater containing azo dyes discharges into the aquatic system, which has recalcitrant and toxic properties. Hence, the need for cost-effective and high-performing technologies is essential. In this direction, bacterial degradation is considered an economically viable and efficient technique for the treatment of Active blue (AB) dye. Polyurethane foam (PUF) is a low-cost and hydrophilic material with a microporous structure, which offers an excellent surface-to-volume ratio. Hence, PUF was preferred for the immobilization of isolated bacterial species. For this, a dye-degrading gram-positive bacteria namely Bacillus cereus GS2 IIT (BHU) was isolated from the petroleum sludge. A comparative analysis between free and immobilized cell systems was carried out by varying the process parameters, i.e., batch time, pH, temperature, glucose concentration, and initial AB dye concentration. The corresponding optimum conditions were found to be 6.0 days, 6.5, 30 °C, 1.0 g/L, and 50 mg/L, respectively. The immobilized cell system exceeds the dye removal efficiency (RE) by 10. 7 % compared to the free cell system. The packed bed bioreactor could be able to deliver 98.56 % of dye removal at an inlet loading rate of 30 mg/L d and 50 mg/L of initial dye concentration. © 2024 Indian Chemical Society
Emergence of Dielectric Properties by Doping of Semi-Transition Metal in Semiconductor Complex Perovskite Oxide
(John Wiley and Sons Inc, 2023) Vishnu Shankar Rai; Dinesh Prajapati; Manish Kumar Verma; Vinod Kumar; Atendra Kumar; Tapas Das; Kedar Sahoo; Narsingh Bahadur Singh; Kamdeo Mandal
The effect of zinc substitution at the Cu2+ site and germanium substitution at the Ti4+ site in bismuth copper titanate, Bi2/3Cu3Ti4O12, is investigated. Composition with x = 0.05 is synthesized by semi-wet route in the system Bi2/3Cu3Ti4−xGexO12 (BCTGO) and Bi2/3Cu3−xZnxTi4−xGexO12 (BCZTGO) that are sintered at 1123 K for 8 h. Crystal structure has remained cubic. The phase formations of these ceramics are confirmed by the X-ray diffraction. The microstructural analysis of the samples is done by scanning electron microscopy and tunneling electron microscopy. Elemental analysis is performed by energy dispersive X-ray spectroscopy. X-ray photoelectron spectroscopy suggests that all elements present in these ceramics are in proper oxidation states. The dielectric constant is found high for BCTGO-0.05 ceramic. The specific capacitances of BCTGO-0.05 and BCZTGO-0.05 are found to be 13.05 and 15.7 F g−1, respectively. Optical band gap values (Eg) of BCTGO-0.05 and BCZTGO-0.05 ceramics are found as 1.77 and 1.91 eV. © 2023 Wiley-VCH GmbH.
Graphene-based nanocomposites: An efficient detoxification agent for heavy metal removal from wastewater
(National Institute of Science Communication and Policy Research, 2023) Sanjeev Verma; Shivani Verma; Tapas Das; Bhawna Verma
Numerous scientific and technological developments in wastewater treatment procedures are brought on by the shortage of clean water supplies. Heavy metals' recalcitrance in wastewater has been shown to be a difficult issue. Further, drinking water quality must be at its highest for human health to be at its best; nevertheless, a number of human activities are continuously degrading it, which has an effect on human health either directly or indirectly. Because heavy metals are the primary causes of many chronic illnesses and have a tendency to bio accumulate, they are giving rise to a lot of worries. Technologies from all over the world are being developed to address the demand for clean drinking water. The objective of the current study is to raise awareness of the need to remove dangerous dense metals from various types of wastewater and the application of modified graphene nanocomposite for their adsorption-based removal. Graphene-based nanocomposite materials have been picked for this application due to their large surface area, superior mechanical strength, and reactivity towards polar and nonpolar contaminants for the electrostatic emission of the heavy metal ions arsenic (As), chromium (Cr), copper (Cu), and lead (Pb). © 2023, National Institute of Science Communication and Policy Research. All rights reserved.
Nanowires for Flexible Electrochemical Energy Devices
(CRC Press, 2023) Tapas Das; Sanjeev Verma; Vikas Kumar Pandey; Bhawna Verma
The demand for flexible electronics devices has been increasing due to their excessive use in implantable medical equipment, artificial skins, roll-up displays, and wearable devices. Huge specific energy and specific power flexible energy storage backup systems are required to operate the flexible devices. Nanowire is such a type of one-dimensional material, which can provide flexibility and mechanical stability to an energy storage device. Nanowires provide direct pathways to current flow, resulting in facilitation of electron movement more than other structures. The large specific surface area of nanowires enhances the contact area between electrode-electrolyte and as a result, the specific capacitance, energy, and power energy storage device increases. This chapter covers the use of nanowires in flexible energy storage devices, like supercapacitors, lithium-ion, sodium-ion, metal-air batteries, etc. Different types of carbon, polymer, organic, inorganic, and composite nanowires have been discussed briefly. Finally, the existing issues along with the current outlook have been addressed in this chapter. © 2023 selection and editorial matter, Ram K. Gupta.