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Analytical Models to Predict Power Harvesting with Piezoelectric Transducer
Raghava Raju Muppala,K. Padma Raju,Nam Mee Moon,Baek Ho Jung 한국전자파학회JEES 2008 Journal of Electromagnetic Engineering and Science Vol.8 No.1
Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from piezoelectric transducer. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually vibrating system into electrical energy that can be stored and used to power other devices. Micro- to milli-watts power can be generated from vibrating system. We developed definitive and analytical models to predict the power generated from a cantilever beam attached with piezoelectric transducer. Analytical models are pin-force method, enhanced pin-force method and Euler-Bernoulli method. Harmonic oscillations and random noise will be the two different forcing functions used to drive each system. It has been selected the best model for generating electric power based upon the analytical results obtained.
Sirangi, Subash,Jogam, Phanikanth,Nemali, Gandhi,Ajmeera, Ragan,Abbagani, Sadanandam,Raju, Vatsavaya S. The Korean Society of Plant Biotechnology 2020 JOURNAL OF PLANT BIOTECHNOLOGY Vol.47 No.4
The genetic diversity of two subpopulations of Corynandra chelidonii, one of terrestrial and the other of aquatic environments, was measured with molecular markers, such as start codon targeted (SCoT), inter simple sequence repeats (ISSR), and random amplification of polymorphic DNA (RAPD). The traditional morphological traits such as habitat, habit, leaf morphology, the colour of the sepals and petals, number of stamens, and seed morphology formed the base for their realization as two varieties, C. chelidonii var. pallae and C. chelidonii var. chelidonii. The polymorphism between the two variants was 100% with the primers SCoT-2 and OPA-1 and 4, while maximum polymorphism was detected with ISSR-2, SCoT-3, and OPA-3. The study used, for the first time, more than one molecular marker to assess the genetic variation underscoring the morphological variation in Corynandra chelidonii (L.f.) Cochrane & Iltis. The study justifies the recognition of the two subpopulations of Corynandra chelidonii from aquatic and terrestrial environments as two distinct varieties, C. chelidonii var. pallae (Reddy & Raju) V.S.Raju and C. chelidonii var. chelidonii, respectively, based on the traditional taxonomic evidence.
Raju, Kati,Kim, Seyoung,Hyung, Choi Jae,Yu, Ji Haeng,Seong, Young-Hoon,Kim, Soo-Hyun,Han, In-Sub Elsevier 2019 CERAMICS INTERNATIONAL Vol.45 No.1
<P><B>Abstract</B></P> <P>In this paper, we report on the selection of an optimal sintering temperature for Ce<SUB>0.9</SUB>Gd<SUB>0.1</SUB>O<SUB>2−δ</SUB>–La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>Co<SUB>0.2</SUB>Fe<SUB>0.8</SUB>O<SUB>3–δ</SUB> composites through characterization of their microstructural, mechanical, and elastic properties. For this selection, sintering was performed mainly at three different temperatures—1100, 1250, and 1400 °C—for 3 h. The samples were systematically investigated in terms of their relative density, microstructure, flexural strength, hardness, elastic modulus, and Poisson's ratio. An increase in density with an increase in sintering temperature was observed to cause a significant improvement in the flexural strength, hardness, and elastic modulus. However, an excessively high temperature (>1250 °C) was detrimental to the flexural strength and hardness because of the occurrence of grain growth. The optimal sintering temperature was identified to be 1250 °C from an analysis of samples with superior mechanical properties and adequate elastic properties. The optimal flexural strength and hardness were found to be 211 ± 21 MPa and 9.34 ± 0.5 GPa, respectively, at room temperature.</P>
Raju, G. Seeta Rama,Pavitra, E.,Bharat, L. Krishna,Rao, Gattupalli Manikya,Jeon, Tae-Joon,Huh, Yun Suk,Han, Young-Kyu Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.12
<P><B>Abstract</B></P> <P>Upconversion Sr<SUB>2</SUB>(Gd<SUB>.98-<I>x</I> </SUB>Er<SUB>.02</SUB>Yb<SUB> <I>x</I> </SUB>)<SUB>8</SUB>Si<SUB>6</SUB>O<SUB>26</SUB> (SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP>) phosphor materials were synthesized using a citrate sol-gel process. X-ray diffraction patterns confirmed their hexagonal structure. Field emission scanning electron microscopy images of SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP> phosphors depicted submicron particles. The enhanced upconversion luminescence properties of SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP> phosphors were analysed as a function of Yb<SUP>3+</SUP> ion concentration and laser power. The energy transfer induced enhanced emission of the Er<SUP>3+</SUP>/ Yb<SUP>3+</SUP> ions co-doped SGSO phosphors was ascribed to multi-phonon relaxation. The calculated chromaticity coordinates of the SGSO:2Er<SUP>3+</SUP>/<I>x</I>Yb<SUP>3+</SUP> phosphors showed emissions could be tuned by changing Yb<SUP>3+</SUP> ion concentration. Optimized sample exhibited the chromaticity coordinate values near to the ultra-high definition television standard green emission coordinates.</P>
Raju Nandhakumar,Yun Soo Ahn,Hoe-Jin Yoon,김관묵 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.12
New receptors 1-3 that bind stereoselectively amino alcohols and convert chirality of amino acidsvia imine bond formation were synthesized. The receptors have uryl (1), thiouryl (2) and guanidinium (3) groups all with additional phenylcarbonyl motifs, which are effective hydrogen bonding donors and play a key role in the stereoselective recognitions. The stereoselectivities were measured from the integration of 1H NMR peaks. Compound 1 and 2 showed the stereoselectivities for the imine formation with amino alcohols (KR/KS) in the range of 2 ~ 4, and compound 3 in the range of 4 ~ 8. Chirality conversion efficienciesof 1-3 for amino acids, i.e. D/L ratio at equilibrium, are in the range of 1.5 ~ 5.6, showing a little higher efficiency with 3. The additional phenylcarbonyl motifs in 1-3 were revealed not to contribute to significant enhancement of the selectivities.
Raju, R. Srinivasa,Reddy, G. Jithender,Rao, J. Anand,Rashidi, M.M. Society for Computational Design and Engineering 2016 Journal of computational design and engineering Vol.3 No.4
The numerical solutions of unsteady hydromagnetic natural convection Couette flow of a viscous, incompressible and electrically conducting fluid between the two vertical parallel plates in the presence of thermal radiation, thermal diffusion and diffusion thermo are obtained here. The fundamental dimensionless governing coupled linear partial differential equations for impulsive movement and uniformly accelerated movement of the plate were solved by an efficient Finite Element Method. Computations were performed for a wide range of the governing flow parameters, viz., Thermal diffusion (Soret) and Diffusion thermo (Dufour) parameters, Magnetic field parameter, Prandtl number, Thermal radiation and Schmidt number. The effects of these flow parameters on the velocity (u), temperature (${\theta}$) and Concentration (${\phi}$) are shown graphically. Also the effects of these pertinent parameters on the skin-friction, the rate of heat and mass transfer are obtained and discussed numerically through tabular forms. These are in good agreement with earlier reported studies. Analysis indicates that the fluid velocity is an increasing function of Grashof numbers for heat and mass transfer, Soret and Dufour numbers whereas the Magnetic parameter, Thermal radiation parameter, Prandtl number and Schmidt number lead to reduction of the velocity profiles. Also, it is noticed that the rate of heat transfer coefficient and temperature profiles increase with decrease in the thermal radiation parameter and Prandtl number, whereas the reverse effect is observed with increase of Dufour number. Further, the concentration profiles increase with increase in the Soret number whereas reverse effect is seen by increasing the values of the Schmidt number.
Advancement in energy harvesting magneto-rheological fluid damper: A review
Raju Ahamed,Md Meftahul Ferdaus,Yancheng Li 한국유변학회 2016 Korea-Australia rheology journal Vol.28 No.4
In this paper, a comprehensive review of the present literature on energy generated magnetorheological (MR) fluid based damper, modeling and applications of the MR damper are presented. The review starts with an introduction of the basic of MR fluid and their different modes, consequences with different types of MR fluids based devices, and their relevant applications. Besides, various forms of MR damper and its applications are presented. Following this, the modeling of the MR fluids and the modeling of the MR fluid based damper are deliberated according to arrangement and configurations. Finally, the review ends with the design and advancement issues, performance analysis matters, and analytical modeling of energy generated magnetorheological fluid damper systems.
Raju, G. Seeta Rama,Pavitra, E.,Ko, Yeong Hwan,Yu, Jae Su The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.31
<P>Stable CaMoO<SUB>4</SUB> spherulites were synthesized by a facile hydrothermal method using (NH<SUB>4</SUB>)<SUB>6</SUB>Mo<SUB>7</SUB>O<SUB>24</SUB>·4H<SUB>2</SUB>O as a Mo source and these spherulites were formed according to the theoretical predictions of the crystal splitting theory. Rietveld refinement and photoluminescence studies confirmed that the CaMoO<SUB>4</SUB> spherulites are defect-free. The CaMoO<SUB>4</SUB> spherulites showed greenish-blue emission and the single emitting component of CaMoO<SUB>4</SUB>:Eu<SUP>3+</SUP> spherulites led to a novel excitation induced efficient emission property like organic light emitting diodes. Cathodoluminescent properties of the CaMoO<SUB>4</SUB>:Eu<SUP>3+</SUP> exhibited individual emissions from MoO<SUB>4</SUB><SUP>2−</SUP> clusters and Eu<SUP>3+</SUP> ions. The white color emissions were clearly explained using Gaussian fitting curves. The corresponding CIE chromaticity coordinates provided their emission potentiality in the green, red and white regions for optical and biological applications.</P> <P>Graphic Abstract</P><P>Stable CaMoO<SUB>4</SUB> spherulites with tunable luminescent properties have been synthesized and the growth mechanism is in well agreement with the theoretical predictions of the crystal splitting theory. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm32049e'> </P>