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Effect of lanthanum,neodymium on piezoelectric,dielectric and ferroelectric properties of PZT

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Journal of Advanced Ceramics 2013年第1期2卷 37-41页

作者： Benudhar sahoo Prasanta kumar PANDA Materials Science Division CSIR-National Aerospace LaboratoriesKodihalliP.B.No.1779Bangalore 560017India

The effect of La^(3+)and Nd^(3+)on piezoelectric,dielectric and ferroelectric properties of PZT(Pb(Zr_(0.53)Ti_(0.47))O_(3))was *** powders were prepared by“wet-chemical”route followed by calcination at 800℃for 4 *** analysis of the calcined powders confirms the tetragonal phase in the undoped PZT,which gradually decreases with the dopant concentration and the appearance of rhombohedral phase *** study of sintered pellets reveals the decrease in grain size with the increase in dopant concentration beyond 0.02 mol Nd^(3+)and 0.03 mol La^(3+)*** piezoelectric constant(d_(33))and dielectric properties were maximum for 0.02 mol Nd^(3+)and 0.03 mol La^(3+)*** remnant polarization of La^(3+)-doped sample was higher than Nd^(3+)-doped sample,and the sample with combined dopants shows intermediate remnant polarization(P_(r)).Based on the above study,it is concluded that La^(3+)is more effective than Nd^(3+),including in a mixture of La^(3+)and Nd^(3+)dopants.

关键词： lead zirconate titanate wet-chemical piezoelectric dielectric ferroelectric

Adaptive Three-phase Estimation of Sequence Components and Frequency Using H∞ Filter Based on Sparse Model

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Journal of Modern Power Systems and Clean Energy 2020年第5期8卷 981-990页

作者： Umamani Subudhi Harish kumar sahoo Sanjeev kumar Mishra Department of Electronics and Telecommunication Engineering Indian Institute of Information Technology(IIIT)BhubaneshwarIndia Department of Electronics and Telecommunication Engineering Veer Surendra Sai University of Tecnology(Burla)SambalpurIndia

The estimation of sequence or symmetrical components and frequency in three-phase unbalanced power system is of great importance for protection and *** paper proposes a new H∞filter based on sparse model to track the sequence components and the frequency of three-phase unbalanced power *** inclusion of sparsity improves the error convergence behavior of estimation model and hence short-duration non-stationary PQ events can easily be tracked in the time *** proposed model is developed using l1 norm penalty in the cost function of H∞filter,which is quite suitable for estimation across all the three phases of an unbalanced *** model uses real state space modeling across three phases to estimate amplitude and phase parameters of sequence ***,frequency estimation uses complex state space modeling and Clarke transformation generates a complex measurement signal from the unbalanced three-phase *** state vector used for frequency estimation consists of two state *** proposed sparse model is tested using distorted three-phase signals from IEEE-1159-PQE database and the data generated from experimental laboratory *** analysis of absolute and mean square error is presented to validate the performance of the proposed model.

关键词： Sequence component Clarke transformation H∞filter state space model

Upgradation of bauxite by molecular hydrogen and hydrogen plasma

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International Journal of Minerals,Metallurgy and Materials 2016年第10期23卷 1141-1149页

作者： B.R.Parhi S.k.sahoo S.C.Mishra B.Bhoi R.k.Paramguru B.k.Satapathy Department of Metallurgical and Materials Engineering National Institute of Technology Rourkela 769008 Odisha India Institute of Minerals and Materials Technology Bhubaneswar 751013 Odisha India kalinga Institute of Industrial Technology Bhubaneswar 751024 Odisha India National Aluminium Company Ltd. Bhubaneswar 751013 Odisha India

An approach was developed to upgrade the bauxite ore by molecular hydrogen and hydrogen plasma. A gibbsite-type bauxite sample was obtained from National Aluminium Company（NALCO）, Odisha, India. The obtained sample was crushed and sieved（to 100 μm） prior to the chemical analysis and grain-size distribution study. The bauxite sample was calcined in the temperature range from 500 to 700°C for different time intervals to optimize the conditions for maximum moisture removal. This process was followed by the reduction of the calcined ore by molecular hydrogen and hydrogen plasma. Extraction of alumina from the reduced ore was carried out via acid leaching in chloride media for 2 h at 60°C. X-ray diffraction, scanning electron microscopy, thermogravimetry in conjunction with differential scanning calorimetry, and Fourier transform infrared spectroscopy were used to determine the physicochemical characteristics of the material before and after extraction. Alumina extracted from the reduced ore at the optimum calcination temperature of 700°C and the optimum calcination time of 4 h is found to be 90% pure.

关键词： upgrading bauxite calcination leaching alumina extraction

Lubrication of dry sliding metallic contacts by chemically prepared functionalized graphitic nanoparticles

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Friction 2020年第4期8卷 708-725页

作者： Suprakash SAMANTA Santosh SINGH Rashmi R.sahoo Surface Engineering&Tribology Division CSIR-Central Mechanical Engineering Research InstituteDurgapur 713209India Academy of Scientific and Innovative Research(AcSIR) Ghaziabad 201002India

Understanding the mechanism of precision sliding contacts with thin, adherent solid nano lubricating particle films is important to improve friction and wear behavior and ensure mechanical devices have long service lifetimes. Herein, a facile and multistep approach for the preparation of graphene oxide (GO) is presented. Subsequently, surface modification of as-synthesized GO with octadecyl amine (ODA) is performed to prepare hydrophobic GO-ODA and with 6-amino-4-hydroxy-2-naphthalenesulfonic acid (ANS) to prepare amphoteric GO-ANS through a nucleophilic addition reaction. X-ray diffraction and ultraviolet-visible, Fourier transform infrared, and Raman spectroscopy provide significant information about the reduction of oxygen functionalities on GO and the introduction of new functionalities in GO-ODA and GO-ANS. The effects of particle functionalization for the improved control of particle adhesion to the tribocontact have been studied. Wettability and thermal stability were determined using the water contact angle, and atomic force microscopy and differential scanning calorimetry (DSC) were used to characterize particle adhesion to the tribocontact. The tribological performances of the particles have been investigated using macro- and micro-tribometry using pin/ball-on-disc contact geometries. The influence of particle functionalization on the contact pressure and sliding velocity was also studied under rotating and reciprocating tribo-contact in ambient conditions. With an increase in the contact pressure, the functionalized particles are pushed down into the contact, and they adhere to the substrate to form a continuous film that eventually reduces friction. Amphoteric GO-ANS provides the lowest and most steady coefficient of friction (COF) under all tested conditions along with low wear depth and minimal plastic deformation. This is because particles with superior wetting and thermal properties can have better adherence to and stability on the surface. GO-ANS ha

关键词： solid lubricants nanoparticles carbon graphite sliding friction and wear adhesion electron microscopy

A facile synthesis of a novel optoelectric material: a nanocomposite of SWCNT/ZnO nanostructures embedded in sulfonated polyaniline

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International Journal of Smart and Nano Materials 2014年第3期5卷 180-193页

作者： Rajesh k.Agrawalla Rima Paul Pratap k.sahoo Amit k.Chakraborty Apurba krishna Mitra Physics NIT DurgapurDurgapur 713209India b Physics NISERBhubaneswarIndia

Functionalized single-walled carbon nanotubes(f-SWCNTs)hybridized with freshly prepared zinc oxide(ZnO)nanocrystals have been found to be good luminescent material with tuned emission properties.A three-phase nanocomposite of sulfonated polyaniline embedded with such SWCNT/ZnO nanostructures has been prepared by a simple solution mixing chemical process and characterized by using high-resolution transmission electron microscopy,X-ray diffractometry,Raman spectroscopy,Fourier transform infrared spectroscopy,and thermogravimetric *** study of UVvisible absorption and photoluminescence spectroscopies reveal that the ternary polymer nanocomposite is a luminescent material with enhanced emission *** an increase in DC conductivity indicates that the nanocomposite is also a good conductive material,satisfying Mott’s variable range hopping model for a two-dimensional *** a three-phase nanocomposite may find extensive application in dye-sensitized solar cells,sensors,and supercapacitors.

关键词： SPANI SWCNT/ZnO hybrid polymer nanocomposite

Synthesis and characterization of manganese tetroxide(Mn_(3)O_(4))nanofibers by electrospinning technique

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Journal of Advanced Ceramics 2013年第1期2卷 26-30页

作者： Benudhar sahoo Prasanta kumar PANDA Materials Science Division CSIR-National Aerospace LaboratoriesKodihalliP.B.No.1779Bangalore 560017India

Manganese tetroxide(Mn_(3)O_(4))nanofibers were prepared by electrospinning homogeneous viscous solution of 20 wt%,28 wt%and 36 wt%manganese acetate in poly vinyl alcohol(PVA)and calcining the nanofibers at 1000℃for 2 *** was carried out at 9 kV DC with tip to collector distance(TCD)of 7 *** gravimetric analysis(TGA)of the fibers indicates the pure phase of manganese oxide above 500℃.XRD analysis of calcined(at 1000℃)nanofibers indicates the formation of phase-pure tetragonal Mn_(3)O_(4).Scanning electron microscopy(SEM)studies show the fibers cylindrical with the diameters in the range of 100-600 nm and aspect ratio>*** general,the average diameter of the green fibers decreases with the increase in manganese acetate *** diameter of calcined nanofibers is reduced by 34%.

关键词： electrospinning manganese tetroxide poly vinyl alcohol nanofiber

MHD flow and heat transfer from continuous surface in uniform free stream of non-Newtonian fluid

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Applied Mathematics and Mechanics(English Edition) 2007年第11期28卷 1467-1477页

作者： Bikash sahoo H.G Sharma Department of Mathematics Indian Institute of Technology RoorkeeRoorkeeUttarakhand-247667India

An analysis is carried out to study the steady flow and heat transfer characteristics from a continuous flat surface moving in a parallel free stream of an electrically conducting non-Newtonian viscoelastic fluid. The flow is subjected to a transverse uniform magnetic field. The constitutive equation of the fluid is modeled by that for a second grade fluid. Numerical results are obtained for the distribution of velocity and temperature profiles. The effects of various physical parameters like viscoelastic parameter, magnetic parameter and Prandtl number on various momentum and heat transfer characteristics are discussed in detail and shown graphically.

关键词： second grade fluid free stream heat transfer magnetic field finite difference method

Magnetic Flux Alignment Studies on Entrapped Ferrofuid Nanoparticles in Poly Vinyl Alcohol Matrix

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Journal of Materials Science & Technology 2013年第10期29卷 903-908页

作者： k.Jeyasubramanian N.Selvakumar J.Ilakkiya P.Santhoshkumar Nikil Satish Sumanta kumar sahoo Nano Science and Technology Lab Department of Mechanical EngineeringMepco Schlenk Engineering College Department of ECE Jay Shriram Group of Institutions Department of ECE Adhiyamaan College of Engineering Department of Metallurgical and Materials Engineering National Institute of Technology

Highly surface active super paramagnetic colloidal suspensions of nano crystalline ferrofluid have been synthesized through wet-chemical route. Entrapment of magnetic domains presented in the nano ferrofluid in a polymer matrix like poly vinyl alcohol film was accomplished by developing polymer composite film in between two magnetic poles by solvent casting method. Similarly poly vinyl alcohol-ferrofluid composite films were also developed in the absence of magnetic field. Atomic force microscopy image of nano-composite film makes it clear that the film developed in the absence of magnetic field possesses randomly oriented domains, whereas film developed with magnetic field shows well aligned flux lines. The characteristics and nature of forces acting between magnetic domains along the magnetic flux lines were explored from magnetic force microscopy imaging. The number of flux lines developed in the polymer matrix was observed to be directly proportional to applied external magnetic field. Approximate number of magnetic lines passing through unit area of composite film was evaluated from line profile data analysis of atomic force microscopy image. The particle sizes of the nanoparticles encapsulated in the polymer matrix were found to be in the range of 10- 20 nm. Scanning electron microscopy micrographs confirm aggregation of ferrofluid particles of ribbon like morphology along the magnetic flux lines. Magnetic properties of the entrapped nanoparticles in polymer matrix film were analyzed using vibrating sample magnetometer at room temperature. The super paramagnetic nature and other magnetic properties were evaluated from the hysteresis loop.

关键词： Ferrofiuid Magnetic field fines Alignment Super paramagnetic

Coronary artery disease presenting as intractable hiccups:an unclear mechanism

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Journal of Geriatric Cardiology 2021年第5期18卷 398-399页

作者： Alor sahoo Sarabjeet Singh Central Cardiology Medical Center BakersfieldCAUSA Central Cardiology Medical Center Cedars-SinaiCollege of Osteopathic MedicineTouro University CaliforniaVallejoCAUSA

A 66yearold gentleman presented for a cardiovascular evaluation secondary to chest discomfort,right knee pain,and intractable *** patient also had type 2 diabetes mellitus,hypercholesterolemia,aortic atherosclerosis,and ascending aortic *** family history was also significant for premature coronary artery disease in the *** patient had been compliant with his medical therapy,which included subcutaneous 200 units/mL insulin degludec,18 mg/3 mL subcutaneous liraglutide,daily oral 500 mg metformin hydrochloride,daily oral 100 mg sitagliptin,daily oral 12.5 mg zolpidem,daily oral 5 mg tadalafil,and 20 mg tablet rosuvastatin daily.

关键词： artery cardiovascular intractable