http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
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,Seong, Young-Hoon,Yoon, Dang-Hyok The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.4
In this paper, the joining characteristics of GDC-LSM ceramics with Crofer 22 APU metal alloys was investigated at different brazing temperatures and holding times by reactive air brazing. Brazing was performed using Ag-10 wt% CuO filler, at three different temperatures (1000, 1050, and 1100℃ for 30 minutes) as well as for three different holding times (10, 30, and 60 minutes at 1050℃). The interfacial microstructures were examined by scanning electron microscopy and the joining strengths were assessed by measuring shear strengths at room temperature. The results show that with increasing brazing temperature and holding time, joint microstructure changed obviously and shear strength was decreased. Shear strength varied from a maximum of 100±6 MPa to a minimum of 18±5 MPa, depending on the brazing conditions. These changes were attributed to an increase in the thickness of the oxide layer at the filler/metal alloy interface.
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.
Joining of metal-ceramic using reactive air brazing for oxygen transport membrane applications
Raju, K.,Muksin,Kim, S.,Song, K.s.,Yu, J.H.,Yoon, D.H. Elsevier Ltd 2016 Materials & Design Vol.109 No.-
<P>This study examined the joining of dense Ce0.9Gd0.1O2 (-) (delta)-La0.6Sr0.4Co0.2Fe0.8O3 (-) (delta) (GDC-LSCF) ceramics to high temperature metal alloys for the fabrication of multilayered oxygen transport membrane (OTM) stacks. Reactive air brazing using a silver-based paste was performed at 1050 degrees C for 30 min in air to join GDC-LSCF/high temperature alloys, such as AISI 310S, Inconel 600 and Crofer 22 APU. The effects of the various filler materials, including CuO, GDC, LSCF, and GDC-LSCF mixture, in the Ag paste were also examined. The Ag-10 wt% CuO braze filler ensured in a reliable and compact joining without the formation of cracks and voids at the joining interface, while the addition of other ceramic fillers resulted in incomplete joining. Although none of the GDC-LSCF/metal alloy joints showed gas leakage at room temperature, the GDC-LSCF/Crofer joint only maintained the gas-tightness up to 800 degrees C under pressurized air up to 7 bars, which was explained by the microstructural rigidness of the oxide layer formed on the filler/alloy interface at high temperatures. This was supported by the minimal decrease in shear strength of the GDC-LSCF/Crofer joint, which was 91.1 and 88.3 MPa for the as-brazed and isothermally aged joint at 800 degrees C for 24 h in air, respectively. (C) 2016 Published by Elsevier Ltd.</P>
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>
Raju, Kati,Kim, Seyoung,Yu, Ji Haeng,Kim, Soo-Hyun,Seong, Young-Hoon,Han, In-Sub Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.9
<P><B>Abstract</B></P> <P>The phase purity and crystal structure of dual-phase Ce<SUB>.9</SUB>Gd<SUB>.1</SUB>O<SUB>2–δ</SUB>–La<SUB>.6</SUB>Sr<SUB>.4</SUB>Co<SUB>.2</SUB>Fe<SUB>.8</SUB>O<SUB>3–δ</SUB> (GDC–LSCF) composites were refined using data obtained from X-ray diffraction (XRD) by employing the Rietveld method. Rietveld analysis indicated that the structures of GDC and LSCF phases are well crystallized as cubic <I>Fm</I> 3 ̅ <I>m</I> and rhombohedral <I>R</I> 3 ̅ <I>c</I> space groups, respectively. Scanning electron microscopy images showed smooth and dense structures, depicting a homogeneous crystalline structure of the samples. When the composites were cooled from their sintering temperature (1250 °C), compressive stresses were generated in the GDC and corresponding tensile stresses were generated in the LSCF due to differences in thermal expansion coefficients. The compressive residual stresses of the composites were investigated by high-angle XRD measurements using the well-known sin<SUP>2</SUP>ψ method. The average compressive residual stresses in GDC phase are estimated to be − 312 and − 290 MPa for 80 GDC–20 LSCF and 50 GDC–50 LSCF, respectively. The aim of this study is to provide a better understanding of the crystal structures and residual stresses in GDC–LSCF composites through XRD and the suitability of these composites for oxygen transport membranes.</P>
Features of Foliar Epidermis and Stomata in Some Kuphorbiaceae Subfamily Oldfieldioideae
Raju Vatsavaya S . 한국식물학회 1988 Journal of Plant Biology Vol.31 No.2
The features of foliar epidermis and stomata are studied in nine genera representing all the four tribes of the subfamily Oldfieldioideae of the family Euphorbiaceae. On both sides of the leaf, the cuticle is generally smooth with more or less straight epidermal anticlinal walls. The epidermal cells are polygonal and their size varied with species on both sides. The costal cells are either distinct (Dissiliaria, Oldfieldia, etc.) or indistinct (Caletieae). In the taxa examined, the stomata are confined to the abaxial epidermis and diffusely orientated except in Caletieae. They are basically of brachyparacytic type; however, they are anomocytic in Androstachys and of a special type in Mischodon. A systematic consideration of these features showed that they are not only useful in revealing relationships within the subfamily but also of aid in the classification.