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Preparation and Antibacterial Activity of Silver Nanoparticles

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Journal of Biomaterials and Nanobiotechnology 2011年第4期2卷 472-475页

作者： Ratan Das Sneha Gang Siddhartha sankar nath 不详

Uniform silver nanoparticles have been prepared through the chemical reduction of silver ions by ethanol in presence of sodium linoleate. TEM micrograph shows a uniform distribution of the particles with an average size of 12 nm. Further, the antimicrobial activity of silver nanoparticles shows that these nanoparticles can be used as effective growth inhibitors against Staphylococcus Basillus, Staphylloccoccus Aureus, and Pseudimonas Aureginosa.

关键词： Linoleic Acid Absorption Band Colloid Antimicrobial Microorganisms

APPLICATION OF FUZZY CLUSTERING TECHNIQUE FOR ANALYSIS OF NORTH INDIAN OCEAN TROPICAL CYCLONE TRACKS

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Tropical Cyclone Research and Review 2015年第3期4卷 110-123页

作者： sankar nath S.D.KOTAL P.K.KUNDU India Meteorological DepartmentNew DelhiIndia Department of Mathematics Jadavpur UniversityKolkataIndia

A fuzzy, c-means(FCM) clustering technique is explored to investigate the track of tropical cyclones over the North Indian Ocean(NIO) for the period(1976-2014). A total of fi ve clusters is objectively identifi ed based on partition index,partition coeffi cient, Dunn Index and separation index. The results obtained during analysis emphasized that each cluster has the unique features in terms of their genesis location, landfall, travel duration, trajectory, seasonality, accumulated cyclone energy and Intensity. Analysis of large scale environmental parameters, constructed preceding day of genesis show some of these parameters to be potential precursors to TC formation for almost all the clusters, most prominently, mid-tropospheric humidity, zonal wind,vorticity and outgoing long wave radiation of the main developing regions. The individual clusters have the several distinct features in their seasonal *** cluster C5 shows distinct bimodal distributions where as other clusters are formed throughout the year. ENSO infl uenced the cyclone frequency in two of the fi ve clusters. The MJO is found to play an important role in the genesis of the cyclone. The post monsoon season cyclone frequency is more in MJO phase 2, 3 and 4. The technique(FCM) can be used as a guideline in terms of the probable affected zone of TC Tracks by the operational forecasters.

关键词： tropical cyclone North Indian Ocean cluster analysis fuzzy c-means clustering

Classical interpretations of relativistic precessions

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Chinese Physics B 2014年第4期23卷 147-156页

作者： sankar Hajra Indian Physical Society 2A & 2B Raja S. C. Mallick Road

Relativists have exposed various precessions and developed ingenious experiments to verify those phenomena with extreme precisions. The Gravity Probe B mission was designed to study the precessions of the gyroscopes rotating round the Earth in a nearly circular near-Earth polar orbit to demonstrate the geodetic effect and the Lense-Thirring effect as predicted by the general relativity theory. In this paper, we show in a very simple and novel analysis that the precession of the perihelion of Mercury, the Thomas precession, and the precession data （on the de Sitter and Lense-Thirring precessions） collected from the Gravity Probe B mission could easily be explained from classical physics, too.

关键词： Thomas precession precession of planetary orbits de Sitter precession Lense-Thirring precession

Three-mode optomechanical system for angular velocity detection

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Chinese Physics B 2018年第8期27卷 254-260页

作者： Kai Li sankar Davuluri Yong Li Beijing Computational Science Research Center Beijing 100193China

We propose a scheme for measuring the angular velocity of absolute rotation using a three-mode optomechanical system in which one mode of the two-dimensional （2D） mechanical resonator is coupled to an optical cavity. When the total system rotates, the Coriolis force acting on the 2D mechanical resonator due to the absolute rotation will affect the mechanical motion and thus change the phase of the output field from the cavity. The angular velocity of the absolute rotation can be estimated by monitoring the spectrum of the output field from the cavity via homodyne measurement. The minimum measurable angular velocity, which is determined by the noise spectrum, is calculated. The working range of the gyroscope for measuring angular velocity is discussed.

关键词： optomechanics gyroscope

Detection and Localization of Load Redistribution Attacks on Large-scale Systems

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Journal of Modern Power Systems and Clean Energy 2022年第2期10卷 361-370页

作者： Andrea Pinceti Lalitha sankar Oliver Kosut the School of Electrical Computer and Energy EngineeringArizona State UniversityTempeUSA

A nearest-neighbor-based detector against load redistribution attacks is *** detector is designed to scale from small-scale to very large-scale systems while guaranteeing consistent detection *** testing is performed on a realistic large-scale system to evaluate the perfor-mance of the proposed detector against a wide range of attacks,from simple random noise attacks to sophisticated load redistribution *** detection capability is analyzed against different attack parameters to evaluate its sensitivity.A statistical test that leverages the proposed detector is introduced to identify which loads are likely to have been maliciously modified,thus,localizing the attack *** test is based on ascribing to each load a risk measure(probability of being attacked)and then computing the best posterior likelihood that minimizes log-loss.

关键词： Attack detection cyber-security false data injection(FDI)attack load redistribution attack machine learning nearest neighbor

Gasification kinetic modelling of Victorian brown coal chars and validity for entrained flow gasification in CO_(2)

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International Journal of Mining Science and Technology 2021年第3期31卷 473-481页

作者： Tao Xu Yongping Wu sankar Bhattacharya College of Energy Engineering Xi’an University of Science and TechnologyXi’an 710054China Department of Chemical Engineering Monash UniversityVictoria 3800Australia

The gasification kinetic modelling of two Victorian brown coal(Yallourn and Maddingley)chars and the validity for entrained flow gasification were investigated in this *** study was conducted in a thermogravimetric analyzer(TGA)at 750–1100℃,30%–90%CO_(2)concentration using different char particle sizes within 20–106 *** was found that random pore model and modified volumetric model are applicable for TGA results,but volumetric model and grain model are *** effect of particle size under106 mm on gasification rate is very *** energies of Maddingley char and Yallourn char in CO_(2)gasification are 219–220 and 197–208 k J/mol,*** pre-exponential factors are in the same order of magnitude,and they increased as particle size decreased.A mathematical model was developed to predict carbon conversion over time for entrained flow gasification of Victorian brown coal chars at 1000–1400℃.

关键词： Victorian brown coal Gasification kinetics Modelling Entrained flow gasification

Suitable triggering algorithms for detecting strong ground motions using MEMS accelerometers

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Earthquake Engineering and Engineering Vibration 2015年第1期14卷 27-35页

作者： Ravi sankar Jakka Siddharth Garg Department of Earthquake Engineering Indian Institute of Technology

With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record a seismic event depends upon the efficiency of triggering algorithm, apart from the sensor＇s sensitivity. There are several classic triggering algorithms developed to detect seismic events, ranging from basic amplitude threshold to more sophisticated pattern recognition. Algorithms based on STA/LTA are reported to be computationally efficient for real time monitoring. In this paper, we analyzed several STA/LTA algorithms to check their efficiency and suitability using data obtained from the Quake Catcher Network （network of MEMS accelerometer stations）. We found that most of the STA/LTA algorithms are suitable for use with MEMS accelerometer data to accurately detect seismic events. However, the efficiency of any particular algorithm is found to be dependent on the parameter set used （i.e., window width of STA, LTA and threshold level）.

关键词： strong ground motion triggering algorithms seismic event detection MEMS accelerometers STA/LTA based algorithms

Numerical Study of Double Diffusive Convection in Partially Heated Vertical Open Ended Cylindrical Annulus

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Advances in Applied Mathematics and Mechanics 2010年第6期2卷 763-783页

作者： Mani sankar Department of Mathematics East Point College of Engineering and TechnologyBangalore-560049India

A numerical investigation of laminar natural double diffusive convection in an open ended vertical cylindrical annulus with unheated entry and unheated exit is *** boundary conditions of uniform wall temperature/uniform wall concentration(UWT/UWC)and uniform heat flux/uniform mass flux(UHF/UMF)are *** of dimensionless induced volume rate Q,average Nusselt number Nu and Sherwood number Sh are obtained for air flow under various buoyancy ratio N,Grashof numbers due to heat and mass transfer GrT and GrM,Schmidt number Sc and combinations of unheated entry,heated section and unheated exit *** the flow under consideration is a boundary layer type,the governing partial differential equations was discretized to a linear system of equations by the use of an implicit finite difference *** nonlinear convective terms are approximated by second upwind difference method for the numerical *** numerical results reveal that the presence of unheated entry and unheated exit severely affects the heat and mass transfer *** numerical solutions are found to approach asymptotically the closed form solutions for fully developed ***,the present numerical results are validated with the existing solutions for pure thermal convection and are found to be in good agreement.

关键词： Discrete heating cylindrical annulus upwind difference doubles diffusive convection buoyancy ratio

Time variant multi-objective linear fractional interval-valued transportation problem

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Applied Mathematics(A Journal of Chinese Universities) 2022年第1期37卷 111-130页

作者： Dharmadas Mardanya sankar Kumar Roy Department of Applied Mathematics with Oceanology and Computer Programming Vidyasagar UniversityMidnapore 721102West BengalIndia

This paper studies a time-variant multi-objective linear fractional transportation problem. In reality, transported goods should reach in destinations within a specific time. Considering the importance of time, a time-variant multi-objective linear fractional transportation problem is formulated here. We take into account the parameters as cost, supply and demand are interval valued that involved in the proposed model, so we treat the model as a multi-objective linear fractional interval transportation problem. To solve the formulated model, we first convert it into a deterministic form using a new transformation technique and then apply fuzzy programming to solve it. The applicability of our proposed method is shown by considering two numerical examples. At last, conclusions and future research directions regarding our study is included.

关键词： fractional transportation problem multi-objective optimization interval number time variant parameter fuzzy programming Pareto optimal solution