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Evaluation of Radarsat-2 quad-pol SAR time-series images for monitoring groundwater irrigation

International Journal of Digital Earth 2019年第10期12卷 1177-1197页

作者： Amit Kumar Sharma Laurence Hubert-moy Buvaneshwari Sriramulu m.sekhar Laurent Ruiz S.Bandyopadhyay Shiv mohan Samuel Corgne Univ Rennes UMR LETG CNRSRennesFrance Indo-French Cell for Water Science Indian Institute of ScienceBangaloreIndia Department of Civil Engineering Indian Institute of ScienceBangaloreIndia UmR 1069 SAS INRAAgro-campus OuestRennesFrance Géosciences Environnement Toulouse Universitéde ToulouseCNRSIRDToulouseFrance EOS Indian Space Research OrganizationBangaloreIndia PLANEX Physical Research LaboratoryAhmedabadIndia

Groundwater assists farmers to irrigate crops for fulfilling the crop-water *** agriculture system is characterized by three cropping seasons known as Kharif(monsoon),Rabi(post-monsoon)and summer(pre-monsoon).In tropical countries like India,monitoring cropping practices using optical remote sensing during Kharif and Rabi seasons is constraint due to the cloud cover,which can be well addressed by microwave remote *** the proposed research,the strength of C-band polarimetric Synthetic Aperture Radar(SAR)time series images were evaluated to classify groundwater irrigated croplands for the Kharif and Rabi cropping seasons of the year *** present study was performed in the Berambadi experimental watershed of Kabini river basin,southern peninsular India.A total of fifteen polarimetric variables were estimated includes four backscattering coefficients(HH,HV,VH,VV)and eleven polarimetric indices for all Radarsat-2 SAR *** cumulative temporal sum(seasonal and dual-season)of these parameters was supervised classified using Support Vector machine(SVm)classifier with intensive ground observation *** results using the best equation(highest accuracy and kappa)shows that the Kharif,Rabi and irrigated double croplands are respectively 9.58 km2(20.6%),16.14 km2(34.7%)and 6.22 km2(13.4%)with a kappa coefficient respectively 0.84,0.74 and 0.94.

关键词： Radarsat-2 Synthetic Aperture Radar Polarimetric Indices Irrigated Cropland Support Vector machine Classifier Kabini Critical Zone Observatory

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Enhancing the energy efficiency for prolonging the network life time in multi-conditional multi-sensor based wireless sensor network

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Journal of Control and Decision 2023年第1期10卷 72-81页

作者： Raviteja Kocherla m.Chandra sekhar Ramesh Vatambeti Research scholar Department of CSEPresidency UniversityBangaloreIndia Department of CSE Presidency UniversityBangaloreIndia Department of CSE CHRIST(Deemed to be University)BangaloreIndia

A wireless sensor network is one of the networks that is highly demanding by various real-timenetworking applications nowadays. A huge amount of sensor nodes is deployed in the networkrandomly and distributed. most of the applications using wireless sensor network (WSN) aresurveillance monitoring applications like a forest, home, healthcare, environment, and remotemonitoring systems. Based on the application usage, the type of sensor, a number of sensornodes are deployed in such a manner where the sensors can be used effectively. But the sensornodes are restricted in the battery and sensing region. Thus, the battery of the sensor nodesis decreased based on the nodes’ function. The energy level of the sensor nodes highly affectsthe network lifetime. Improving the energy efficiency in WSN is one of the most important challengingtasks. most of the earlier research works have proposed various methods, techniques,and routing protocols, but they are application dependent and as a common method. So, thispaper is motivated to propose a multi-Conditional Network Analysis (mCNA) framework for savingthe energy level of the sensor nodes by reducing energy consumption. ThemCNAframeworkinvolves two different clustering processes with cluster head selection, choosing the best nodesbased on the signal strength, and the best route for data transmission. The data transmissionis done by cluster based on source-destination based. The simulation results proved that theproposed mCNA framework outperforms the other existing methods.

关键词： Wireless sensor networks energy efficiency clustering signal strength verification

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Eigen value analysis of composite hollow shafts using modified EmBT formulation considering the shear deformation along the thickness direction

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Defence Technology（防务技术） 2023年第10期28卷 1-12页

作者： Pavani Udatha A.S.sekhar Velmurugan R machine Design Section Department of Mechanical EngineeringIIT MadrasChennai600036India Department of Aerospace Engineering IIT MadrasChennai600036India

Composite hollow shafts are used in power transmission applications due to their high specific stiffness and high specific *** dynamic characteristics of these shafts are important for transmission *** modelling of these shafts is generally carried out using Equivalent modulus Beam Theory(EmBT)and Layerwise Beam Theory(LBT)*** EmBT formulation is modified by considering stacking sequence,shear normal coupling,bending twisting coupling and bending stretching *** is observed that modified EmBT formulation is underestimating the shafts stiffness at lower length/mean diameter(l/dm)*** the present work,a new formulation is developed by adding shear deformation along the thickness direction to the existing modified EmBT *** variation of shear deformation along the thickness direction is found using different shear deformation theories,i.e.,first-order shear deformation theory(FSDBT),parabolic shear deformation theory(PSDBT),trigonometric shear deformation theory(TSDBT),and hyperbolic shear deformation theory(HSDBT).The analysis is performed at l/d_(m) ratios of 5,10,15,20,25,30,35,and 40 for carbon/epoxy composites,E-glass/epoxy composites,and boron/epoxy composite *** results show that new formulation has improved the bending natural frequency of the composite shafts for l/d_(m)mparison with modified *** effect of new formulation is more significant for the second and third bending modes of natural frequencies.

关键词： Composite hollow shafts Bending natural frequency modified EmBT formulation Thickness effect

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Correlation among extinction efficiency and other parameters in an aggregate dust model

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Research in Astronomy and Astrophysics 2017年第11期17卷 95-112页

作者： Tanuj Kumar Dhar Himadri sekhar Das Department of Physics Assam University Silchar 788011 India

We study the extinction properties of highly porous Ballistic Cluster-Cluster Aggregate dust aggregates in a wide range of complex refractive indices （1.4 ≤ n 〈 2.0, 0.001 ≤ k 〈 1.0） and wavelengths （0.11 μm 〈 A 〈 3.4 μm）. An attempt has been made for the first time to investigate the correlation among extinction efficiency （Qext）, composition of dust aggregates （n, k）, wavelength of radiation （A） and size parameter of the monomers （x）. If k is fixed at any value between 0.001 and 1.0, Qext increases with increase of n from 1.4 to 2.0. Qext and n are correlated via linear regression when the cluster size is small, whereas the correlation is quadratic at moderate and higher sizes of the cluster. This feature is observed at all wavelengths （ultraviolet to optical to infrared）. We also find that the variation of Qext with n is very small when A is high. When n is fixed at any value between 1.4 and 2.0, it is observed that Qext and k are correlated via a polynomial regression equation （of degree 1, 2, 3 or 4）, where the degree of the equation depends on the cluster size, n and A. The correlation is linear for small size and quadratic/cubic/quartic for moderate and higher sizes. We have also found that Qext and x are correlated via a polynomial regression （of degree 3, 4 or 5） for all values of n. The degree of regression is found to be n and k-dependent. The set of relations obtained from our work can be used to model interstellar extinction for dust aggregates in a wide range of wavelengths and complex refractive indices.

关键词： light scattering -- ISm: dust extinction

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A Novel Single Switch High Gain DC-DC Converter Topology for Renewable Energy Systems

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Energy Engineering 2021年第2期118卷 199-209页

作者： G.Indira Kishore m.Premkumar Ramesh Kumar Tripathi Chandra sekhar Nalamati GmR Institute of Technology RajamSrikakulamAndhra Pradesh532127India motilal Nehru National Institute of Technology AllahabadUttar Pradesh211004India

Renewable energy with sources such as photovoltaic(PV)or fuel cells can be utilized for the generation of elec-trical *** these sources generate fewer voltage values and therefore require high gain converters to match with DC bus voltage in *** high gain converters can be implemented with switched capacitors to meet the required DC bus *** capacitors operate in a series and parallel combination during switch-ing operation and produce high static gain,limits reverse voltage that appears across the components.A novel converter is proposed that satisfies all the features such as high voltage gain,only one switch,forces less potential stress cross the components,ripple current is *** features of the proposed converter are verified through mATLAB/SImULINK.

关键词： DC-DC converter high gain renewable energy switched capacitors

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Volumetric, Ultrasonic and Transport Properties of Binary Liquid mixtures Containing Dimethyl Formamide at 303.15 K

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Chinese Journal of Chemistry 2007年第1期25卷 32-43页

作者： SYAmALA, Vardhana RAJA sekhar, Damaramadugu SIVA KUmAR, Kasibhatta VENKATESWARLU, Ponneri Thermochemical Laboratories Department of Chemistry Sri Venkateswara University Tirupati 517 502 India Department of Chemistry SVArts College Tirupati 517 502 India

Excess volumes （v^E）, ultrasonic velocities （u）, isentropic compressibility （△Ks） and viscosities （η） for the binary mixtures of dimethyl formamide （DmF） with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at 303.15 K were studied. Excess volume data exhibit an inversion in sign for the mixtures of dimethyl formamide with 1,2- and 1,3-dichlorobenzenes and the property is completely positive over the entire composition range for the mixtures of dimethyl formamide with 1,2,4-trichlorobenzene, o-nitrotoluene and m-nitrotoluene. On the other hand, the quantity is negative for the mixtures of dimethyl formamide with chlorotoluenes. Isentropic compressibility （Ks） has been computed for the same systems from precise sound velocity and density data. Further, deviation of isentropic com- pressibility （△Ks） from ideal behavior was also calculated. AKs values are negative over the entire volume fraction range in all the binary mixtures. The experimental sound velocity data were analysed in terms of Free Length Theory （FLT） and Collision Factor Theory （CFT）. The viscosity data were analysed on the basis of corresponding state approach. The measured data were discussed on the basis of intermolecular interactions between unlike molecules.

关键词： excess volume, dimethyl formamide, interferometer, sound velocity, viscosity molecular interaction

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Aggregate dust model to study the polarization properties of comet C/1996 B2 Hyakutake

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Research in Astronomy and Astrophysics 2010年第4期10卷 355-362页

作者： Himadri sekhar Das Abinash Suklabaidya Saonli Datta majumder Asoke Kumar Sen Department of Physics Assam University

The observed linear polarization data of comet Hyakutake are studied at wavelengths λ=0.365 μm,λ=0.485 μm and 0.684μm through simulations using Ballistic Particle-Cluster Aggregate and Ballistic Cluster-Cluster Aggregate aggregates of 128 spherical *** first found that the size parameter of the monomer,x ～ 1.56-1.70,turned out to be the most suitable which provides the best fits to the observed dust scattering properties at three wavelengths：λ=0.365 μm,0.485μm and 0.684μ***,the effective radius of the aggregate （r） lies in the range 0.45 μm ≤ r ≤ 0.49 μm at λ=0.365 μm;0.60 μm ≤ r ≤ 0.66 μm at λ=0.485 μm and 0.88 μm ≤ r ≤ 0.94 μm at λ=0.684 μ*** using superposition T-mATRIX code and the power-law size distribution,n（r）～ r-3,the best-fitting values of complex refractive indices are calculated for the observed polarization data at the above three *** best-fitting complex refractive indices （n,k） are found to be （1.745,0.095） at λ=0.365 μm,（1.743,0.100） at λ=0.485 μm and （1.695,0.100） at λ=0.684 μ*** refractive indices derived from the present analysis correspond to a mixture of both silicates and organics,which are in good agreement with the in situ measurement of comets by different spacecraft.

关键词： comets:general - dust extinction - scattering - polarization

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In situ deposited cobalt-magnesium selenates as an advanced electrode for electrochemical energy storage

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Journal of magnesium and Alloys 2022年第12期10卷 3565-3575页

作者： manchi Nagaraju S.Chandra sekhar Bhimanaboina Ramulu Shaik Junied Arbaz Jae Su Yu Department of Electronics and Information Convergence Engineering Kyung Hee University1732 Deogyeong-aeroGihung-guYongin-siGyeonggi-do 17104Republic of Korea

Currently,bimetallic selenates have attracted much attention as a prominent electrode composite material for supercapacitors owing to their higher redox chemistry and superior electrical ***,we synthesized cobalt-magnesium selenates (CoSeO3-mg Se O4,CmS) via a facile hydrothermal process,followed by *** first,cobalt-magnesium oxide (Co2.32mg0.68O4,CmO) was in situ prepared by a one-pot hydrothermal *** investigation on the morphological change was performed by synthesizing the same CmO samples at different growth times by keeping the temperature *** CmO electrode designed for 8 h of growth time (CmO-8 h)with an attractive morphology showed a higher areal capacity of 101.7μAh cm-2(at 3 m A cm-2) than the other CmO electrodes prepared for 6 and 10 *** exalted performance was achieved by the selenization of the CmO-8 h sample to form the CmS *** 3 m A cm-2,the resulted CmS exhibited nearly three times higher capacity,i.e.,385.4μAh cm-2,than the CmO-8 h ***,an asymmetric cell fabricated with CmS as a positive electrode also revealed good energy storage *** the applied voltage between 0 and 1.5 V,the asymmetric cell demonstrated maximum energy density of 0.159 m Wh cm-2(18.6 Wh kg-1) and maximum power density of 18.47 m W cm-2(1938 W kg-1),***,novel magnesium-based metal selenates can act as an efficient electrode for energy storage.

关键词： Co2.32mg0.68O4 CoSeO3–mgSeO4 In situ formation Energy storage Asymmetric cell

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Rain tree(Samanea saman)seed oil:Solvent extraction,optimization and characterization

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Journal of Bioresources and Bioproducts 2021年第3期6卷 254-265页

作者： S.Chandra sekhar K.Karuppasamy m.Vimal Kumar D.Bijulal N Vedaraman Ravishankar Sathyamurthy Department of mechanical Engineering N.B.K.R Institute of Technology(Autonomous)Vidyanagar-524413Andra PradeshIndia Department of mechanical Engineering Anna University Regional CampusTirunelveliTamil Nadu627007India Department of mechanical Engineering M.A.M School of EngineeringTiruchirappalli621105Tamil NaduIndia Department of mechanical Engineering Govt.Engineering CollegeBarton HillThiruvananthapuram695035KeralaIndia Department of Chemical Engineering Central Leather Research Institute(CSIR-CLRI)ChennaiTamil Nadu600020India Department of mechanical Engineering KPR Institute of Engineering and TechnologyArasurCoimbatoreTamil Nadu641407India

The present investigation reports the soxhlet assisted solvent extraction technique to derive the oil from seeds of the rain *** optimization of the factors affecting the extraction process has been carried out by Response Surface methodology(RSm)technique,and a Box-Behnken Design(BBD)consisting of three process variables has been developed to optimize the yield of *** the RSm technique,the predicted optimum oil yield of 11.15%at an optimized condition of powder weight of 20 g,volume of solvent of 380 mL,and extraction time of 6 *** physiochemical properties of the oil showed liquid greenish-yellow with 0.88,1.473 of specific gravity and refractive index,***,the moisture content,free fatty acid,acid value,saponification value,iodine value,and peroxide value were found to be 0.16%,13.615,27.23,187.1 mg KOH per g oil,65.8 g I_(2) per 100 g,and 4.02 meq O_(2) per kg,*** the obtained results,it was found that the extracted oil could be used for various applications.

关键词： Soxhlet apparatus Response Surface methodology Box-Behnken design(BBD) Analysis of variance mg per KOH g of oil

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multifunctional core-shell-like nanoarchitectures for hybrid supercapacitors with high capacity and long-term cycling durability

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Nano Research 2019年第10期12卷 2597-2608页

作者： S.Chandra sekhar Goli Nagaraju Bhimanaboina Ramulu Sk.Khaja Hussain D.Narsimulu Jae Su Yu Department of Electronic Engineering Institute for Wearable Convergence ElectronicsKyungHee University1732 Deogyeong-daeroGihurtg-guYongin-siGyeonggi-do 17104Republic of Korea1 Department of Chemical Engineering College of EngineeringKyung Hee University1732 Deogyeong-daeroGihung-guYongin-siGyeonggi-do 17104Republic of Korea

Transition metal oxide/hydroxide with multif unctional hierarchical nano structures has attracted widespread attention in supercapacitors(SCs)because of their large accessible surface area,high electrochemical activity and superior redox ***,core-shell-like copper(Cu)hydroxide nano tube arrays grafted nickel aluminum layered double hydroxide n anosheets were facilely synthesized on porous Cu foam(CH NTAs@NiAI LDH NSs)for use as an efficient battery-type electrode in hybrid *** the synergistic effects of NiAl LDH NSs on well-adhered CH NTAs/CF,the core-shell-like composite(prepared for 24 h)delivered a maximum areal capacity of 334.3 pAh/cm2 at a current density of 3 mA/cm2 in 2 m KOH electrolyte,which is comparatively higher than other samples synthesized at different growth ***,the core-shell-like CH NTAs@NiAI LDH NSs-24 demonstrated an outstanding cycling stability of 134.3%after 10,000 *** high capacity and stability of CH NTAs@NiAI LDH NSs-24,a pouch-type hybrid SC was further assembled with core-shell-like composite as a positive electrode and reduced graphene oxide as a negative electrode with a filter paper as a separator in aqueous alkaline *** hybrid SC showed a high areal capacity of 250 pAh/cm2 at 2 mA/cm2 with maximum areal energy and power densities of 181.9 pWh/cm2 and 24,991.5 pW/cm2,*** harvest!ng the solar energy via solar cell panel and subsequently delivering the stored en ergy to switching and proximity applicati ons also dem on strated the real-time applicability of our hybrid SCs.

关键词： copper hydroxide layered double hydroxides core-shell hybrid supercapacitors energy density self-powered devices

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