Promotional effects of K₂O on Ti, Zr and Mn terinary mixed oxides for the selective production of ethylbenzene with CO₂

( Raju ),최광민,이종학,박상언 한국공업화학회 2006 한국공업화학회 연구논문 초록집 Vol.2006 No.-

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.

Intraspecific genetic variation in Corynandra chelidonii (Angiosperms: Cleomaceae) as revealed by SCoT, ISSR and RAPD analyses

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.

Electrochemical bromination and oxidation of alkyl aromatic compounds by two-phase electrolysis

Raju Thasan,Kulangiappar Kumarasamy 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.3

A simple, regioselective, environmentally clean and economical method for the preparation of side chain/ring brominated aromatic compounds is reported in 70-98% yield by an electrochemical method using two phase electrolysistechnique. Electrochemical reactions were carried out using aqueous 25-50 wt% sodium bromide containingcatalytic amount (5 wt%) of hydrobromic acid as an aqueous phase and chloroform containing alkyl aromatic compoundsas an organic phase, at a temperature of 0-30 oC in an undivided cell. The same two-phase electrolytic system can beused for the oxidation of benzylic alcohols to the corresponding benzaldehydes in 80-94% yield without over oxidationto carboxylic acids. The advantage of this very mild procedure is a room temperature reaction used with an undividedcell. Excellent conversions are observed. After completion of alcohol oxidation the electrolyte can be reused for a numberof times, demonstrating “spent reagent” free electro organic reaction as an attractive one. In the case of side chain/ringbromination of alkyl aromatic compounds, the electrolyte can be reused after making up the concentration of the electrolytewith 47 wt% HBr solution. In some cases homogeneous electrolysis is applied, where the two-phase electrolysisdid not work. Styrene epoxidation and α-bromination of ketones underwent homogeneous electrolysis at room temperaturewithout any catalyst. The reaction was performed in CH3CN-water (3 : 2) using equimolar amount of NaBras an electrolyte to get 68% of styrene epoxide. Use of an ionic liquid 1-butyl 3-methyl imidazolium bromide (Bmim)Br, instead of NaBr improved the yield and current efficiency of styrene epoxide to 86%.

Sintering additives for SiC based on the reactivity: A review

Raju, Kati,Yoon, Dang-Hyok Elsevier 2016 CERAMICS INTERNATIONAL Vol.42 No.16

<P><B>Abstract</B></P> <P>Silicon carbide (SiC) is one of the most attractive materials for high temperature applications, being used in many areas, such as gas turbines, heat exchangers, and space shuttles, because of its excellent strength, oxidation resistance and chemical stability at high temperatures. Moreover, SiC and its composites are being considered as structural materials for advanced fission reactors and future fusion reactors owing to its additional low induced radioactivity under neutron irradiation conditions. On the other hand, pure SiC can only be densified by sintering at high temperatures and pressures because of its high covalent bonding nature and low self-diffusivity. Therefore, the addition of sintering additives is essential for enhancing the densification of SiC. This paper reviews the criteria for the selection of effective SiC sintering additives based on the Gibbs free energy to predict the reactivity between the sintering additive and SiC, particularly for liquid phase sintering at 1700–1900°C. The thermodynamic simulation was verified by offering the experimental results for various types of sintering additives, such as main group metals, metal oxides, and rare earth elements. This review suggests a guideline for the selection of sintering additives for SiC.</P>

Challenges in Total Hip Replacement after McMurray's Osteotomy: A Report of 3 Cases and Review of Literature

Raju Vaishya,Abhishek Vaish,Aabid Husain Ansari 대한정형외과학회 2020 Clinics in Orthopedic Surgery Vol.12 No.4

Background: McMurray’s osteotomy of the hip was a popular surgery practiced for almost 5 decades for the management of the fractured neck of the femur and hip osteoarthritis since its first description in 1936. It is an oblique, medial displacement intertrochanteric osteotomy. In the long term, McMurray's osteotomy patients develop limb length discrepancy and secondary osteoarthritis due to the altered biomechanics of the hip and may require total hip replacement (THR). THR after the previous osteotomy is more challenging than that for unoperated hip joints due to severe distortion of the hip anatomy and soft-tissue contractures. These challenges are related to distorted bony anatomy, soft-tissue contractures, and the choice of implants. Methods: Three patients with previous McMurray's osteotomy of the hip developed secondary osteoarthritis and underwent total hip replacement. We discussed specific challenges encountered during THR and techniques to deal with such problems. Results: All patients had pain-free hip, with minimal residual shortening (average, 1.2 cm) at an average follow-up of 3.67 years (range, 1 to 6 years). The Harris hip score improved significantly postoperatively and no complications were encountered. Conclusions: A detailed and careful preoperative planning, correct execution of surgical techniques, and postoperative rehabilitation are the keys to the successful management of these cases.

A Comparative Analysis of Histogram Equalization based Techniques for Contrast Enhancement and Brightness Preserving

Raju. A,Dwarakish. G. S,D. Venkat Reddy 보안공학연구지원센터(IJSIP) 2013 International Journal of Signal Processing, Image Vol.6 No.5

Performance of non-prismatic simply supported prestressed concrete beams

Raju, P. Markandeya,Rajsekhar, K.,Sandeep, T. Raghuram Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.4

Prestressing is the most commonly employed technique in bridges and long span beams in commercial buildings as prestressing results in slender section with higher load carrying capacities. This work is an attempt to study the performance of a minimum weight prestressed concrete beam adopting a non-prismatic section so that there will be a reduction in the volume of concrete which in turn reduces the self-weight of the structure. The effect of adopting a non-prismatic section on parameters like prestressing force, area of prestressing steel, bending stresses, shear stresses and percentage loss of prestress are established theoretically. The analysis of non-prismatic prestressed beams is based on the assumption of pure bending theory. Equations are derived for dead load bending moment, eccentricity, and depth at any required section. Based on these equations an algorithm is developed which does the stress checks for the given section for every 500 mm interval of the span. Limit state method is used for the design of beam and finite difference method is used for finding out the deflection of a non-prismatic beam. All the parameters of nonprismatic prestressed concrete beams are compared with that of the rectangular prestressed concrete members and observed that minimum weight design and economical design are not same. Minimum weight design results in the increase in required area of prestressing steel.

Enhanced green upconversion luminescence properties of Er³⁺/Yb³⁺ co-doped strontium gadolinium silicate oxyapatite phosphor

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>

Thermal diffusion and diffusion thermo effects on an unsteady heat and mass transfer magnetohydrodynamic natural convection Couette flow using FEM

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.