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Low-temperature green synthesis of boron carbide using aloe vera

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Chinese Physics B 2018年第10期27卷 578-583页

作者： H V sarithaDevi M s swapna G Ambadas s sankararaman Department of Optoelectronics and Department of Nanoscience and Nanotechnology University of Kerala Kariavattom Thiruvananthapuram-695581 Kerala India Government Victoria College Palakkad Kerala India

The unique structural and physical properties of boron carbide, which make it suitable for a wide range of applications,demands the development of low-cost and green synthesis method. In the present work, the commonly available leaves of aloe vera are hydrothermally treated to form the carbon precursor for the synthesis of boron carbide. The morphological characterization reveals the porous nature of the precursor turning into a tubular structure upon boron carbide *** structural characterization by x-ray diffraction and other spectroscopic techniques such as Fourier transform infrared,Raman, photoluminescence and uv-visible near-infrared spectroscopy confirm the formation of boron carbide. The thermogravimetric analysis of the sample is found to exhibit good thermal stability above 500 °C. When the sample is annealed to 600 °C, boron carbide with phase purity is obtained, which is confirmed through XRD and FTIR analyses. The optical emission properties of the sample are studied through CIE plot and power spectrum. Compared with other natural precursors for boron carbide, the aloe vera is found to give a good yield above 50%.

关键词： aloe vera boric acid boron carbide hydrothermal method

structural,magnetic and antibacterial properties of manganese-substituted magnetite ferrofluids

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International Journal of Minerals,Metallurgy and Materials 2023年第7期30卷 1417-1426页

作者： Blessy Babukutty Deepalekshmi Ponnamma swapna s.Nair Jiya Jose saritha G.Bhat sabu Thomas Department of Physics Central University of KeralaKasargod 671314India Materials science and Technology Program College of Arts and SciencesQatar UniversityP.O.Box 2713DohaQatar Department of Biotechnology Cochin University of Science and TechnologyKalamasseryKeralaIndia Department of Chemistry Mahatma Gandhi UniversityKottayam 686560KeralaIndia

Manganese-substituted magnetite ferrofluids(FFs)Mnx Fe_(1-x)Fe_(2)O_(4)(x=0–0.8)were prepared in this work through a chemical coprecipitation *** controlled growth of FF nanomaterials for antibacterial activities is challenging,and therefore,very few reports are available on the *** research focuses on stabilizing aqueous FFs with the tetramethylammonium hydroxide surfactant to achieve high *** characterization reveals nanoparticles of 5–11 nm formed by the chemical reaction and nanocrystalline nature,as evident from structural ***-substituted magnetic FFs are analyzed for their structural,functional,and antibacterial performance according to the Mn-substituent *** studies show a high blue shift for Mn^(2+)-substituted Mnx Fe_(1-x)Fe_(2)O_(4)with the theoretical correlation of optical band gaps with the Mn *** superparamagnetic nature of substituted FFs causes zero coercivity and remanence,which consequently influence the particle size,cation distribution,and spin *** structural and functional performance of the FFs is correlated with the antibacterial activity,finally demonstrating the highest inhibition zone formation for Mnx Fe_(1-x)Fe_(2)O_(4)FFs.

关键词： manganese ferrofluids homogeneity antibacterial stability

Development of Energy Management system for Micro Grid Operation

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Computer systems science & Engineering 2023年第6期45卷 2537-2551页

作者： s.Jayaprakash B.Gopi Murugananth Gopal Raj s.sujith s.Deepa s.swapna school of Electrical and Electronics Engineering Sathyabama Institute of Science and TechnologyChennaiTamil NaduIndia Department of Electronics and Communication Engineering Muthayammal Engineering College(Autonomous)RasipuramTamil NaduIndia Department of Electrical and Electronics Engineering Ahalia School of Engineering and TechnologyKozhiparaPalakkadKeralaIndia Department of Electrical and Electronics Engineering NSS College of EngineeringPalakkadKeralaIndia Department of Electrical and Electronics Engineering Panimalar Engineering CollegeChennaiTamil NaduIndia Department of Electrical and Electronics Engineering GRT Institute of Engineering and TechnologyTiruttaniThiruvallurTamil NaduIndia

The introduction of several small and large-scale industries,malls,shopping complexes,and domestic applications has significantly increased energy *** aim of the work is to simulate a technically viable and economically optimum hybrid power system for residential *** proposed micro-grid model includes four power generators:solar power,wind power,Electricity Board(EB)source,and a Diesel Generator(DG)set,with solar and wind power performing as major sources and the EB supply and DG set serving as backup *** core issue in direct current to alternate current conversion is harmonics distortion,a five-stage multilevel inverter is employed with the assistance of an intelligent control system is simulated and the optimum system configuration is estimated to reduce harmonics and improve the power *** monthly demand for residential buildings is 13-15 ***,almost 433 Kilo-Watts(KW)of electricity is required every day,and if it is used for 8 h per day,50-60 KW of electricity is needed per *** overall micro-grid model’s operation and performance are established using MATLAB/sIMULINK software,and simulation results are *** simulation results show that the developed system is both cost-effective and environment friendly resulting in yearly cost reductions.

关键词： Microgrid energy management system intelligent control system multilevel inverter power plants

Laser-induced thermal lens study of the role of morphology and hydroxyl group in the evolution of thermal diffusivity of copper oxide

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Chinese Physics B 2021年第6期30卷 588-593页

作者： Riya sebastian M s swapna Vimal Raj s sankararaman Department of Optoelectronics University of KeralaTrivandrum 695581KeralaIndia

The paper explores the evolution of thermal behavior of the material by studying the variations in thermal diffusivity using the single beam thermal lens(TL) technique. For this purpose, the decomposition of Cu(OH)_(2) into CuO is studied in a time range up to 120 h, by subjecting the sample to morphological, structural, and spectroscopic characterizations. The time evolution of thermal diffusivity can be divided into three regions for demonstrating the dynamics of the reaction. When the reaction is complete, the thermal diffusivity is also found to be saturated. In addition to the morphological modifications,from rods to flakes, the variations in the amount of hydroxyl group are attributed to be responsible for the enhancement of base fluid's thermal diffusivity by 165%. Thus the study unveils the role of hydroxyl groups in the thermal behavior of CuO.

关键词： thermal diffusivity CuO thermal lens morphology hydroxyl group

Amazonia atlantiicola ***.(Ascomycetes,Meliolales)from Malabar Wildlife sanctuary in Kerala state,India

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studies in Fungi 2017年第1期2卷 14-16页

作者： Lini KM Neeta NN swapna s Post Graduate&Research Dept.of Botany Mar Thoma CollegeThiruvalla-689103PathanamthittaKeralaIndia

A new species,Amazonia atlantiicola,infecting leaves of Atlantia sp.(Rutaceae),was collected from Malabar Wildlife sanctuary of Kozhikode *** is introduced,described and illustrated in this paper.

关键词： Atlantia black mildew new species

Enhanced visible green and 1.5μm radiative emission of Er^(3+)ions in Li_(2)O-PbO-Al_(2)O_(3)-B_(2)O_(3) glasses for photonic applications

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Journal of Rare Earths 2021年第5期39卷 520-525页

作者： Nisha Deopa Mukesh K.sahu sumandeep Kaur Aman Prasad K.swapna Vinay Kumar R.Punia A.s.Rao Department of Physics Chaudhary Ranbir Singh UniversityRohtak Bypass RoadJind126102HaryanaIndia Department of Applied Physics Delhi Technological UniversityBawana RoadNew Delhi110042India Department of Physics K L Educational FoundationVaddeswaram522502Guntur(Dt.)Andhra PradeshIndia Department of Electronics and Communication Engineering Graphic Era(Deemed to be University)Dehradun248002UttrakhandIndia

A series of Er^(3+)ions doped lithium lead alumino borate(LiPbAlB)glasses were synthesized via melt quench method and their structural,physical and optical properties were ***-Ofelt theory in correlation with the emission and absorption profiles was performed for the measurement of various radiative parameters for different transitions of Er^(3+)doped *** as-prepared glasses show deep green(550 nm)as well as NIR(1532 nm)emission at 380 and 980 nm excitation wavelengths,*** intensity of emission spectra increases with Er^(3+)ions concentration up to 1.5 mol%and beyond quenching is *** Dexter theory applied to the emission profiles reveals the interaction between Er^(3+)ions as dipole-dipole in *** color coordinates are found to fall in the green region of the visible *** is observed that 1.5 mol%of Er^(3+)ions concentration is optimum to exhibit the maximum quantum efficiency,branching ratios,gain bandwidth,emission cross-section,gain crosssection and aptly suitable for visible and NIR photonic applications.

关键词： Rare earths Glasses Judd-Ofelt theory Photoluminescence Dexter theory

Integrated dominating and hit set-inspired unequal clusteringbased data aggregation in wireless sensor networks

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International Journal of Intelligent Computing and Cybernetics 2022年第4期15卷 642-655页

作者： G.Vennira selvi V.Muthukumaran A.C.Kaladevi s.satheesh Kumar B.swapna Department of Computer science and Engineering Global Institute of Engineering and TechnologyVelloreIndia Department of Mathematics School of Applied SciencesREVA UniversityBangaloreIndia Department of Computer science and Engineering Sona College of TechnologySalemIndia Department of Computer science School of Applied SciencesREVA UniversityBangaloreIndia Department of Electronics and Communication Engineering Dr MGR Educational and Research InstituteChennaiIndia

Purpose-In wireless sensor networks,improving the network lifetime is considered as the prime objective that needs to be significantly addressed during data *** the traditional data aggregation techniques,cluster-based dominating set algorithms are identified as more effective in aggregating data through cluster ***,the existing cluster-based dominating set algorithms suffer from a major drawback of energy deficiency when a large number of communicating nodes need to collaborate for transferring the aggregated ***,due to this reason,the energy of each communicating node is gradually decreased and the network lifetime is also *** increase the lifetime of the network,the proposed algorithm uses two sets:Dominating set and hit ***/methodology/approach-The proposed algorithm uses two sets:Dominating set and hit *** dominating set constructs an unequal clustering,and the hit set minimizes the number of communicating nodes by selecting the optimized cluster head for transferring the aggregated data to the base *** simulation results also infer that the proposed optimized unequal clustering algorithm(OUCA)is greater in improving the network lifetime to a maximum amount of 22%than the existing cluster head selection approach considered for ***-In this paper,lifetime of the network is prolonged by constructing an unequal cluster using the dominating set and electing an optimized cluster head using hit *** dominator set chooses the dominator based on the remaining energy and its node degree of each *** optimized cluster head is chosen by the hit set to minimize the number of communicating nodes in the *** proposed algorithm effectively constructs the clusters with a minimum number of communicating nodes using the dominating and hit *** simulation result confirms that the proposed algorithm prolonging the lifetime of the network efficiently when compared with the existing algorithms.

关键词： Unequal clustering Hit set Dominating set Network lifetime

Investigation of Li-ion transport in Li7P3s11 and solid-state lithium batteries

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Journal of Energy Chemistry 2019年第11期28卷 1-7页

作者： Chuang Yu swapna Ganapathy Ernst R.H.van Eck Lambert van Eijck Niek de Klerk Erik M.Kelder Marnix Wagemaker Department of Radiation science and Technology Delft University of TechnologyMekelweg 152629JB Delftthe Netherlands Institute for Molecules and Materials Radboud University NijmegenHeyendaalseweg 1356525 AJ Nijmegenthe Netherlands

The high Li-ion conductivity of the Li7P3s11 sulfide-based solid electrolyte makes it a promising candidate for all-solid-state lithium batteries. The Li-ion transport over electrode-electrolyte and electrolyteelectrolyte interfaces, vital for the performance of solid-state batteries, is investigated by impedance spectroscopy and solid-state NMR experiments. An all-solid-state Li-ion battery is assembled with the Li7P3s11 electrolyte, nano-Li2s cathode and Li-In foil anode, showing a relatively large initial discharge capacity of 1139.5 m Ah/g at a current density of 0.064 m A/cm^ 2 retaining 850.0 m Ah/g after 30 cycles. Electrochemical impedance spectroscopy suggests that the decrease in capacity over cycling is due to the increased interfacial resistance between the electrode and the electrolyte. 1D exchange ^7Li NMR quantifies the interfacial Li-ion transport between the uncycled electrode and the electrolyte, resulting in a diffusion coefficient of 1.70(3) ×10^-14cm^2/s at 333 K and an energy barrier of 0.132 e V for the Li-ion transport between Li2s cathode and Li7P3s11 electrolyte. This indicates that the barrier for Li-ion transport over the electrode-electrolyte interface is small. However, the small diffusion coefficient for Li-ion diffusion between the Li2s and the Li7P3s11 suggests that these contact interfaces between electrode and electrolyte are relatively scarce, challenging the performance of these solid-state batteries.

关键词： Li7P3s11 Li-ion transport spin-lattice NMR Exchange NMR solid-state battery

Anthropogenic Edges and Effective Preserve size in the Coast Redwood (sequoia sempervirens (***) Endl.) Forest

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Open Journal of Forestry 2022年第4期12卷 459-478页

作者： Will Russell Nanako Oba swapna Deshpande Department of Environmental studies San Jose State University San Jose USA

Ecological edges created through human activities influence both biotic and abiotic factors within forest communities. The extent of this influence within a preserve is informed by the arrangement, location, and abruptness of edges, as well as the nature of the disturbances that created them. The purpose of this study was to evaluate the impacts of anthropogenic edges on soil and vegetation in the sequoia sempervirens (***) Endl. (coast redwood) forest, and to compare two methods for estimating the effective size of forest preserves. We used a combination of field data and remote image analysis collected in six forest preserves in the santa Cruz Mountains of California. Analysis of field data collected on randomly distributed transects indicated an average depth of influence of 200 meters based on correlations between abiotic and biotic metrics and distance from the forest edge. Abiotic factors including soil temperature and compaction were negatively correlated to distance from the edge in the direction of the forest interior, while soil pH, moisture, and duff depth exhibited positive relationships. Positive correlations were also found for biotic variables including tree canopy cover, the dominance of coast redwood and Notholithocarpus densiflorus (Hook. and Arn.) Manos, C.H. Cannon, and s. Oh (tanoak), total understory plant cover, and the cover of coast redwood forest associated plant species. In contrast, the cover and richness of non-native species were highest for samples closest to the edge. To assess the effective size of preserves, high resolution digital areal images were accessed on an ArcGIs platform. Analysis indicated variation in abruptness between types of edges, with the greatest abruptness found on edges associated with urban development and roads and the lowest abruptness associated with agricultural, grazing, and commercial timber uses. Little variation was exhibited in sinuosity between land use types or in the relative influence of edges for

关键词： Edge Core Area Exurban Coast Redwood