Browsing by Author "Pravin Kumar"

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Bioactive Glass for Biomedical Application: An Overview
(Springer Science and Business Media Deutschland GmbH, 2024) Sushma Yadav; Dharmendra Yadav; Pravin Kumar; Ashishkumar Yadav; Gurudeo Nirala; Sandeep Yadav
The term “bioceramics” describes the ceramics utilized in the reconstruction and restoration of damaged or diseased musculoskeletal system parts. Based on their biological response, bioceramics can be divided into three categories: basically bioinert materials (like zirconia and alumina), bioactive materials (like HA and bioactive glasses), and biodegradable materials (like TCP). Bioactive ceramics, including calcium phosphates, glass–ceramics, and bioactive glasses, can encourage the formation of hydroxyapatite deposits that resemble bone at their surface and offer an interface that contributes to the functional durability of the tissue. An amorphous material with an arbitrary atom configuration is called bioactive glass. The majority of bioactive glasses are mostly composed of SiO2, Na2O, CaO, and P2O5. Fast bonding to bone occurred when the bioactive glass’s silica content was between 42 and 53%. For the production of silicate-, phosphate-, and borate-based bioactive glasses, several compositional modifications are made to the bioactive glasses. They have been employed, among other things, in dental root replacements, middle ear replacements, and bone scaffolds. Bioactive glasses have the ability to form a chemical link with living bone tissue, which is further enhanced by biological responses on the material’s surface. Due of its low mechanical qualities, bioglass cannot be used for large load-bearing applications. These are employed in situations where mechanical strength is not required and regeneration is essential. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Direct Urea Fuel Cells: A Review on Roadmap, Mechanism, Bottleneck, and Future Perspective
(American Chemical Society, 2025) Suraj Goswami; Shankab J. Phukan; Gaurav Gupta; Ranjith Krishna Pai; Sujoy Rana; Manas Roy; Pravin Kumar; Somenath Garai
Direct urea fuel cells (DUFCs) have emerged as an exceptionally viable option for sustainable energy production by utilizing urine- or urea-contaminated wastewater or AdBlue as fuel. In spite of the significant theoretical gravimetric power density, the poor electro-kinetics of the urea oxidation reaction (UOR) obstruct its operational feasibility. Therefore, an improvement of the electrode materials is needed to realize a faster electro-kinetic rate to achieve the scaled-up goals of DUFCs. This review is essential to address the latest developments in urea electrolysis and its mechanistic pathways as explored by the scientific community. Consequently, a panoramic view of the origins, underlying principles, and mechanisms of the UOR-based fuel cells are also highlighted. Additionally, the contemporary progress on transition metal oxides and their alloy-based, mixed oxide-based “nanocarbon” materials, such as carbon nanotubes, and graphene-based electrocatalysts for UOR in alkaline electrolytes discussed in detail. Furthermore, upon optimizing energy efficiency and mitigating capital investments, the economic viability of various catalytic designs is also highlighted, including structural modulation and elemental doping to accelerate the rate of UOR from the very outset to the most recent findings. Finally, the significant challenges impeding the advancement of UOR catalyst-derived DUFCs are also laid out with futuristic perspectives. © 2025 American Chemical Society.
Estimation of drinking water supply and its future trends in Varanasi city, India
(University of Craiova, Faculty of Social Sciences, Department of Geography, 2018) Vineet Kumar Rai; Pravin Kumar; Praveen Kumar Rai
The current study shows the estimation of drinking water supply, future trends and related issues in Varanasi City, India. Varanasi (from 25 0 13'N to 25 0 24'N latitudes and from 82 0 54'E to 83 0 04'E longitude) is one of the most important and historic city located almost in the Middle Ganga valley in the northern plain of India. For the convenience of civic administration, the city is presently divided into 90 wards and for the purpose of extending adequate and safe water supply facilities to the entire area, the city has been divided presently into 16 water supply zones of which 5 zones lie in the trans-Varuna area and the remaining 11 zones in the cis-Varuna area. The present work is based on the secondary sources of data which are obtained from Water Supply Department (Jal Sansthan), Nagar Nigam (Municipal Corporation) of Varanasi. In the first phase of the study, data pertaining to ward wise generation of water supply is collected from Water Supply Department, NNV (Nagar Nigam Varanasi). Informal focused group discussion, PRA (Participatory Action Research), and observation technique were applied to get the first hand information about the water supply scenario in the city. In the second phase of the study, Arc GIS 10.1 software was used to create maps for estimation of water supply management. The population growth in Varanasi from 2011 to 2041 is estimated to have a growth of 21% in 30 years at a rate of 2.25 % per year. This growth rate is considered in the model from 2011 to 2041 to predict the water demand in the city. The data was collected from various municipalities as per the office records. It is estimated that the amount of drinking water requirement forecasted for 2021, 2031 and 2041 is 0.49, 0.76 and 1.17 Billion liters per day respectively in Varanasi City. These data show that with an increase in population, the water demand is also increasing decade after decade. Increasing population growth rate, decreasing surface water resources, overexploitation of groundwater, deterioration of ground water quality and poor sewage treatment are the major water supply related issues in Varanasi city, India. © 2018 University of Craiova, Faculty of Social Sciences, Department of Geography. All rights reserved.
Influence of La3+ doping on structural and optical properties of SrCeO3 perovskite
(Institute of Physics, 2024) Dharmendra Yadav; Pravin Kumar; Alok Kumar Tripathi; Ram Sagar Yadav; Gurudeo Nirala; Sushma Yadav; Ashish Kumar Yadav; Sandip Yadav
The SrCe1-xLaxO3 (x = 0.0, 0.02, 0.4, 0.6, and 0.10) perovskite materials have been successfully synthesized by auto-combustion method and calcined at 1100°C. The XRD patterns reveal a highly crystalline orthorhombic crystal structure with a Pnma space group in all samples. The TEM micrograph shows a spherical morphology of the 10 mol% La3+ doped SrCeO3 perovskite sample alongwith the SAED pattern confirming its highly crystalline nature. The incorporation of La3+ ion in the SrCeO3 perovskite has been confirmed by the Raman and Fourier transform infrared (FTIR) measurements. The UV-vis absorption spectra at room temperature show various bands, with a strong absorption band observed below 400 nm. The optical band gap of the undoped and La3+ doped samples have been calculated and it is smaller for the La3+ doped perovskite samples than that of the undoped perovskite sample. Therefore, the La3+ doped SrCeO3 perovskite may be applicable for optoelectronic applications. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Influence of Lanthanum Doping on Structural and Electrical/Electrochemical Properties of Double Perovskite Sr2CoMoO6 as Anode Materials for Intermediate-Temperature Solid Oxide Fuel Cells
(American Chemical Society, 2019) Pravin Kumar; Paramananda Jena; P.K. Patro; R.K. Lenka; A.S.K. Sinha; Prabhakar Singh; Rajendra Kumar Singh
Lanthanum (La3+)-doped double perovskites Sr2CoMoO6 (Sr2-xLaxCoMoO6, 0.00 ≤ x ≤ 0.03) were synthesized via the citrate-nitrate autocombustion route. The Reitveld refinement analysis of X-ray diffraction reveals the tetragonal symmetry as the main phase with space group I4/m and also confirms the presence of some peaks corresponding to extra phase SrMoO4. The SEM micrograph images reflect that grains are in irregular shape and sizes for all samples. Average grain size gradually decreases with the increase of the SrMoO4 phase. The X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of mixed valence states of Mo5+/Mo6+, Co2+/Co3+, and O-lattice/O-chemisorbed/O-physisorbed species. Coefficient of thermal expansion (CTE) analysis shows that the particular composition Sr1.97La0.03CoMoO6 has the lowest CTE value among the compositions studied. The electrical conductivity of Sr2CoMoO6 is enhanced effectively by doping La at Sr sites. The measured area-specific resistance (ASR) for the composition Sr1.97La0.03CoMoO6 (SLCM03) is found to be appreciably low, â0.053 Ohm cm-2 at 800 °C. The obtained highest electrical conductivity with the lowest activation energy and low ASR value for the composition Sr1.97La0.03CoMoO6 encompasses it as a promising candidate for anode material in the intermediate-temperature solid oxide fuel cell (IT-SOFC) application. © 2019 American Chemical Society.
Theoretical investigation on sensing of the epinephrine neurotransmitter by doped C60 fullerenes
(Elsevier B.V., 2025) Tarun Kumar Yadav; Anil Kumar Vishwkarma; Ehsan Shakerzadeh; Jost Adam; Pravin Kumar; Vetrivelan Vaithiyanathan; Amit Pathak; Minh Tho Nguyen
This study focuses on the adsorption behavior of the epinephrine (EPH) neurotransmitter onto the surface of pristine, B- and Si- doped C60 fullerenes, using density functional theory (DFT) calculations at the B3LYP/6–31 G(d,p) level of theory. The adsorption performance is analyzed through structural, electronic, and energetic features. Results indicate that EPH physisorbs onto the pristine C60 with a slight adsorption energy of −1.7 kcal/mol, while the introduction of B- and Si- doping significantly increases the adsorption energies to −14.2 and −37.3 kcal/mol, respectively, when oxygen atom of OH- group of side chain of EPH interacts with C59B and C59Si fullerenes. This increase may be attributed to a larger number of N-H···π, C-H···π and O-H···π interactions. Epinephrine adsorption onto the surface of fullerenes induces a reduction in the energy gap, which correlates with enhanced electrical conductivity and sensitivity towards EPH. The increased magnitude of the dipole moment in the aqueous phase exhibited by the most favorable nanohybrids of pristine, B-, and Si- atom doped fullerenes results in enhanced solubility, a key parameter for their function in the human body. Based on the electron localization function (ELF) and reduced density gradient (RDG) analyses, significant charge transfer from B- or Si- atoms of the doped fullerene to the oxygen of the EPH is observed, revealing the charge-transfer nature of the nanohybrids. Moreover, Gibbs free energy calculations in both the gas and aqueous phases confirm the spontaneity of EPH adsorption onto the fullerene's surface. Consequently, B- and Si- doped fullerenes are introduced as promising chemical sensors for the EPH neurotransmitter. © 2025 Elsevier B.V.
Women empowerment through women agripreneurship development in India
(Agri Bio Research Publishers, 2015) Shoji Lal Bairwa; Udhav Prasad Singh; Pravin Kumar; Reena Roy
Women empowerment is necessary for the growth and development of the national as well as world economy. Women empowerment includes the social, economical and entrepreneurial empowerment and evaluated in terms of participation, access, employment opportunities and decision making. This article deals with concept, emerging areas and constraints of women empowerment and women agripreneurship development. Women empowerment is instrumentally important for achieving positive developmental outcomes and well-being of life in true sense.