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Search Results: 1 - 10 of 1144 matches for " Yengula Venkata Narayana "
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Post-Buckling Behavior of Laminated Composite Cylindrical Shells Subjected to Axial, Bending and Torsion Loads  [PDF]
Yengula Venkata Narayana, Jagadish Babu Gunda, Ravinder Reddy Pinninti, Markandeya Ravvala
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.34019
Abstract: In present work, post-buckling behavior of imperfect (of eigen form) laminated composite cylindrical shells with different L/D and R/t ratios subjected to axial, bending and torsion loads has been investigated by using an equilibrium path approach in the finite element analysis. The Newton-Raphson approach as well as the arc-length approach is used to ensure the correctness of the equilibrium paths up to the limit point load. Post-buckling behavior of imperfect cylindrical shells with different L/D and R/t ratios of interest is obtained and the theoretical knock-down factors are reported for the considered cylindrical shells.
Rectangular Patch Array Antenna with Liquid Crystal Substrate for Ka and Q Band Applications
I.Govardhani,M.Venkata Narayana
International Journal of Computer Science and Communication Networks , 2012,
Abstract: This paper mainly deals with the design of Microstrip rectangular patch array antenna on liquid crystal substrate at 40GHz. The antenna parameters are simulated using commercial Ansoft HFSS software and the detailed explanation of performance evaluation is presented. A 4x4 rectangular patch array was designed on liquid crystal substrate material and their return loss, input impedance, gain and antenna parameters are studied and presented in this paper.
A Lossless Image Compression Using Traditional and Lifting Based Wavelets
B Eswara Reddy,K Venkata Narayana
Signal & Image Processing , 2012,
Abstract: In this paper an attempt has been made to analyse different wavelet techniques for image compression.Both hand-designed and lifting based wavelets are considered. Hand designed wavelets considered in thiswork are Haar wavelet, Daubechie wavelet, Biorthognal wavelet, Demeyer wavelet, Coiflet wavelet andSymlet wavelet. Lifting based wavelet transforms considered are 5/3 and 9/7. Wide range of images,including both color and gray scale images were considered. These wavelet transforms are used tocompress the test images competitively by using Set Partitioning In Hierarchical Trees (SPIHT) algorithmand by incorporating lifting concepts. Set Partitioning In Hierarchical Trees is a new advanced algorithmbased on wavelet transform which is gaining attention due to many potential commercial applications inthe area of image compression. These algorithms resulted in practical advantages, such as, superior lowbit rate performance, bit-level compression, progressive transmission by pixel, accuracy and resolution.The SPIHT coder is also a highly refined version of the EZW algorithm and is a powerful imagecompression algorithm, that produces an embedded bit stream form, in which the best reconstructedimages shows a significant perceptual improvement as well as an increased PSNR.
Influence of Single Use and Combination of Reductants on the Size, Morphology and Growth Steps of Gold Nanoparticles in Colloidal Mixture  [PDF]
Ahmad Alshammari, Angela K?ckritz, Venkata Narayana Kalevaru, Abdulaziz Bagabas, Andreas Martin
Open Journal of Physical Chemistry (OJPC) , 2012, DOI: 10.4236/ojpc.2012.24033
Abstract: A comprehensive investigation on the formation mechanism of gold nanoparticles (AuNPs) in colloidal mixture obtained from the reduction of chloroauric acid (HAuCl4) solution using a single reducing agent (sodium citrate; process-I), (tannic acid; process-II), and a combination of two reducing agents (sodium citrate plus tannic acid; process-III) is reported. The growth steps at different time intervals during synthesis of colloidal AuNPs were monitored in situ and ex situ using various methods for all the three processes. The measurement of changes in the surface plasmon band position of colloidal AuNPs, along with dynamic light scattering results gave important information for the first assessing of particle size, shape and distribution. Besides, the size and morphological changes at different stages during different processes were also analyzed by transmission electron microscopy. The final Au particles of processes-I & II exhibited different shapes (spherical and nanowires) with particle size and nano wire diameter of 12 nm and 17 nm, respectively. Nevertheless, combination of two reductants (process-III) surprisingly leads to drastically reduced size (ca. 3 nm) with spherical morphology compared to their parent solutions with either of single reducing agent. This result clearly indicates that the combination of reductants has a significant influence on the particle size, morphology and formation mechanism.
Antenna Performance Improvement in Elliptical Array Using RMI Method of Mutual Coupling Compensation  [PDF]
Aluru Venkata Lakshmi Narayana Rao, Nunna Bala Ankaiah, Dharma Raj Cheruku
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2016, DOI: 10.4236/jemaa.2016.81002
Abstract: The number of wireless electronic gadgets used in mobile communication, vehicle collision avoidance system, compact radars, etc. is extremely increasing at a rapid rate. Thus, the characteristics of the antennas involved in these gadgets are to be designed very stringently so as to avoid interferences & coupling and to improve compatibility, susceptibility, etc. Compact smart antenna with improved performance is highly essential to meet this challenging scenario. Mutual coupling between various elements of an array is one of the main factors which can be considered for improvement of performance of the antenna. Influence of mutual coupling on performance of the antenna is considered in this paper and various techniques to minimize this effect are presented. Effect of mutual coupling on radiation characteristics of the antenna can be compensated employing various methods like Conventional Mutual Impedance (CMI), Receiving Mutual Impedance (RMI). Analysis is presented as comparison between the two methods for different number of elements in the array. Analysis is also presented for different geometries of the array like circular and elliptical for improved performance. The results show performance improvement in the proposed array for parameters like SNR and Speed of convergence.
Supply Chain Management in a Dairy Industry - A Case Study
K. Venkata Subbaiah,K. Narayana Rao,K. Nookesh babu
Lecture Notes in Engineering and Computer Science , 2009,
Drug, dosage and activity studies of antimalarials by physical methods – II
Vedam Rama Murthy,Donkena Venkata Raghuram,Pirala Narayana Murthy
Bioinformation , 2007,
Abstract: Studies pertaining to Drug-DNA interactions in treating a disease efficiently have taken an important place in recent times. Murthy et al were active in correlating the drug activity, with physical parameters like refractivity, susceptibility, molecular electron ionization cross-section and the dosage. The molecular polarizability αM, diamagnetic susceptibility χM and molecular electron ionization cross-section Q have been evaluated. An analysis of Q in the light of the data available on Plasma Protein Binding, Bio availability, Log p and Half-Life show semblance of regular dependence of Q on them and hence an effort is made to bring this dependence into a regular mathematical relationship. The dosage of each drug is calculated. A critical look at the results arrived on Q and dosages reveal that a highly active drug with large Q need to be monitored in very small quantities and any minute increase in dosage is resulting in unwanted toxic effects and vice versa. The algebraic formulae enable one to calculate the dosages theoretically from the value of Q and other parameters and the calculated dosage through the formulae agreed favourably well with suggested dosages. For example, in Primaquine Phosphate, the calculated dosage is 30mg/day against the suggested practical dosage of 26.3 mg/day. A similar observation is made in Mepacrine with theoretical dosage of 60 mg/day as against the suggested practical dosage of 100 mg/ day. In short, the molecular structure followed by refraction and susceptibility measurements and Q will throw light on dosage, toxicity of a drug. Thus the present investigations pave way for a new direction of approach for study of drug activity without recourse to techniques involving highly expensive instrumentation and highly theoretical approaches involving quantum mechanical methods.
Evaluation of performance metrics of leagile supply chain through fuzzy MCDM
D. Venkata Ramana,K.Narayana Rao,J. Suresh Kumar
Decision Science Letters , 2013, DOI: 10.5267/j.dsl.2013.03.003
Abstract: Leagile supply chain management has emerged as a proactive approach for improving business value of companies. The companies that face volatile and unpredictable market demand of their products must pioneer in leagile supply chain strategy for competition and various demands of customers. There are literally many approaches for performance metrics of supply chain in general, yet little investigation has identified the reliability and validity of such approaches particularly in leagile supply chains. This study examines the consistency approaches by confirmatory factor analysis that determines the adoption of performance dimensions. The prioritization of performance enablers under these dimensions of leagile supply chain in small and medium enterprises are determined through fuzzy logarithmic least square method (LLSM). The study developed a generic hierarchy model for decision-makers who can prioritize the supply chain metrics under performance dimensions of leagile supply chain.
β-Cyclodextrin mediated synthesis of 1,8-dioxooctahydroxanthenes in water
Swapna Kokkirala,Narayana Murthy Sabbavarapu,Venkata Durga Nageswar Yadavalli
European Journal of Chemistry , 2011, DOI: 10.5155/eurjchem.2.2.272-275.359
Abstract: An experimentally simple, efficient Michael addition reaction was developed for the synthesis of various 1,8-dioxooctahydroxanthene derivatives with 1,3-cyclohexanedione/5,5-dimethyl 1,3-cyclohexane dione and different aldehydes by using β-cyclodextrin as a catalyst in water. A biomimetic approach was employed and the corresponding products were obtained in good to excellent yields. β-cyclodextrin can be recovered and reused upto four cycles without loss of catalytic activity.
Spin-phonon coupling in multiferroic RCrO$_3$ (R-Y, Lu, Gd, Eu, Sm): A Raman study
Venkata Srinu Bhadram,B. Rajeswaran,A. Sundaresan,Chandrabhas Narayana
Physics , 2012, DOI: 10.1209/0295-5075/101/17008
Abstract: Raman study on a select few orthochromites, RCrO$_3$ (R = Y, Lu, Gd, Eu and Sm) shows that the phonon behavior at TN in compounds with magnetic R-ion (Gd and Sm) is remarkably different from that of non-magnetic R-ion (Y, Lu and Eu). While anomalies in most of the observed phonon frequencies in all these compounds may result from the distortion of CrO$_6$ octahedra due to size effect and magnetostriction arising from Cr-ordering, the anomalous behavior of their linewidths observed at TN for the compounds with only magnetic R-ion suggests spin-phonon coupling. The presence of spin-phonon coupling and the anomalies in the low frequency modes related to R-ion motion in orthochromites (R = Gd and Sm) support the suggestion that the coupling between 4f-3d moments play important role in inducing switchable electric polarization.
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