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Search Results: 1 - 10 of 458009 matches for " J. N. Prakash "
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The Role of Fillers on Friction and Slide Wear Characteristics in Glass-Epoxy Composite Systems  [PDF]
B. Suresha, G. Chandramohan, J. N. Prakash, V. Balusamy, K. Sankaranarayanasamy
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2006, DOI: 10.4236/jmmce.2006.51006
Abstract: The comparative performance of Glass-Epoxy (G-E) composite systems interfaced with graded fillers has been examined. In this study, composite materials were experimentally investigated under varying load and sliding velocities by using a Pin-on-Disc type wear tester. The influence of two inorganic fillers, silicon carbide particles (SiC) and graphite, on the wear of the glass fabric reinforced epoxy composites under dry sliding conditions has been investigated. For increased load and sliding velocity situations, higher wear loss was recorded. Some of these observations are supplemented by scanning electron microscopic (SEM) investigations. The coefficients of frictional values show an increasing trend with subsequent increase in load/sliding velocities. It was observed that the Graphite filled G-E composite shows lower coefficient of friction than the other two composites irrespective of variation in the load/sliding velocities. SiC filled G-E composite exhibited the maximum wear resistance. Further, wear of the matrix, breakage of reinforcing fibers, matrix debris formation and interface separation were observed in unfilled and graphite-filled G-E composites. Other interesting SEM features have been noticed and discussed.
Comparison of the Mechanical Properties of AL6061/Albite and AL6061/Graphite Metal Matrix Composites  [PDF]
A. Ramesh, J. N. Prakash, A. S. Shiva Shankare Gowda, Sonnappa Appaiah
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.82009
Abstract: The aim of this present investigation is to carry out a comparative study of the mechanical properties of AL6061/Albite composites containing albite(NaAlSi3O8) particulates, which are naturally occurring plagioclase feldspar and AL6061/graphite particulate composites containing graphite particles. The reinforcing particulates in the MMC’s vary from 0% to 4% by weight. The 'vortex method' of production was employed to fabricate the composites, in which the reinforcements were poured into the vortex created by stirring the molten metal by means of a mechanical agitator. The composites so produced were subjected to a series of tests. The results of this study revealed that as the Albite particle content was increased, there were significant increases in the ultimate tensile strength, hardness and Young's modulus, accompanied by a reduction in its ductility. There was, however, only a very marginal increase in the compressive strength, where as in graphite reinforced composites as the graphite content was increased, there were significant reduction in hardness and monotonic increases in the ductility, ultimate tensile strength (UTS), compressive strength and Young's modulus of the composite, An attempt is made in the paper to provide explanations for these phenomena.
Effect of Particulate Reinforcements on the Mechanical Properties of Al6061-WC and Al6061-Gr MMCs  [PDF]
A. R. K. Swamy, A. Ramesha, G.B. Veeresh Kumar, J. N. Prakash
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.1012087
Abstract: This paper presents the comparative study of the mechanical properties of Al6061-Tungsten carbide composites containing Tungsten carbide (WC) particulate, and Al6061-graphite particulate composites containing graphite particles. The reinforcing particulates in the MMCs vary from 0% to 4% by weight. The 'vortex method' of production was employed to fabricate the composites, in which the reinforcements were poured into the vortex created by stirring the molten metal by means of a mechanical agitator. The composites so produced were subjected to a series of tests. The results of this study revealed that as the Tungsten carbide particle content was increased, there were significant increases in the ultimate tensile strength, hardness and Young's modulus, accompanied by a reduction in its ductility. There was, however, only a very marginal increase in the compressive strength, where as in graphite reinforced composites as the graphite content was increased, there were significant reduction in hardness and monotonic increases in the ductility, ultimate tensile strength (UTS), compressive strength and Young's modulus of the composite, An attempt is made in the paper to provide explanations for these phenomena.
Effect of Particulate Reinforcement on the Mechanical Properties of Al2024-WC MMCs  [PDF]
K. Punith Gowda, J. N. Prakash, Shivashankare Gowda, B. Satish Babu
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2015, DOI: 10.4236/jmmce.2015.36049
Abstract: The present work reveals the study of mechanical properties of Al2024-Tungsten carbide MMCs containing tungsten carbide (WC) particulates. The reinforcing particulates in the Al2024 alloy were varied from 0% to 5% by weight. The vortex method of cast production was employed to fabricate the MMCs, in which the reinforcement was poured into the vortex created by stirring the molten metal by means of a mechanical agitator. The composite so produced was subjected to a series of mechanical tests. The results of this study revealed that as the tungsten carbide particle content was increased, there were significant increases in the ultimate tensile strength, hardness and young’s modulus, compressive strength, accompanied by a reduction in its ductility. An attempt is made in the paper to provide explanations for these phenomena.
Lightning stroke distance estimation from single station observation and validation with WWLLN data
V. Ramachandran, J. N. Prakash, A. Deo,S. Kumar
Annales Geophysicae (ANGEO) , 2007,
Abstract: A simple technique to estimate the distance of the lightning strikes d with a single VLF electromagnetic wave receiver at a single station is described. The technique is based on the recording of oscillatory waveforms of the electric fields of sferics. Even though the process of estimating d using the waveform is a rather classical one, a novel and simple procedure for finding d is proposed in this paper. The procedure adopted provides two independent estimates of the distance of the stroke. The accuracy of measurements has been improved by employing high speed (333 ns sampling rate) signal processing techniques. GPS time is used as the reference time, which enables us to compare the calculated distances of the lightning strikes, by both methods, with those calculated from the data obtained by the World-Wide Lightning Location Network (WWLLN), which uses a multi-station technique. The estimated distances of the lightning strikes (77), whose times correlated, ranged from ~3000–16 250 km. When d<3500 km, the average deviation in d compared with those calculated with the multi-station lightning location system is ~4.7%, while for all the strokes it was ~8.8%. One of the lightnings which was recorded by WWLLN, whose field pattern was recorded and the spectrogram of the sferic was also recorded at the site, is analyzed in detail. The deviations in d calculated from the field pattern and from the arrival time of the sferic were 3.2% and 1.5%, respectively, compared to d calculated from the WWLLN location. FFT analysis of the waveform showed that only a narrow band of frequencies is received at the site, which is confirmed by the intensity of the corresponding sferic in the spectrogram.
ANALYSIS OF BIOACTIVE COMPOUNDS AND ANTIMICROBIAL ACTIVITY OF MARINE ALGAE KAPPAPHYCUS ALVAREZII USING THREE SOLVENT EXTRACTS
V. Prabha*, D.J. Prakash and P.N. Sudha
International Journal of Pharmaceutical Sciences and Research , 2013,
Abstract: The seaweeds are economically valuable resources, used as food, fodder, fertilizer and medicine and thus useful to mankind in many ways. In the present study, Kappaphycus alvarezii, a marine alga, has been analysed for the presence of bioactive products using three solvent extracts. Antimicrobial activity was also done using the same extracts of seaweed. The results revealed that the selected seaweed has active secondary metabolites and also exhibited antimicrobial activity, mainly in the methanolic extract of Kappaphycus alvarezii.
RP-HPLC Method for the Estimation of Nelfinavir Mesylate in Tablet Dosage Form
K. Vanitha Prakash,J. Venkateswara Rao,N. Appala Raju
Journal of Chemistry , 2007, DOI: 10.1155/2007/654706
Abstract:
Rubber friction on (apparently) smooth lubricated surfaces
M. Mofidi,B. Prakash,B. N. J. Persson,O. Albohl
Physics , 2007, DOI: 10.1088/0953-8984/20/8/085223
Abstract: We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short wavelength roughness, which may give the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the substrate surface asperities. The presented results are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.
Quantification of Urban Expansion Using Geospatial Technology—A Case Study in Bangalore  [PDF]
Puspa P. Dash, Ritu Kakkar, V. Shreenivas, P. Jeya Prakash, D. J. Mythri, K. H. Vinaya Kumar, Vanashree Vipin Singh, R. M. N. Sahai
Advances in Remote Sensing (ARS) , 2015, DOI: 10.4236/ars.2015.44027
Abstract: Quantification of urban expansion helps us to understand human induced effects on the environment in a temporal scale. Growing urbanization in Bangalore has resulted in demand for more space and resources. Since last 15 years the landuse and landcover of Bangalore area has been changed drastically due to increase in settlement, urban infrastructure, opening of roads and metros etc. Using geospatial tools, we studied the changes in landuse and landcover over 19 years (1992-2011) of period and changes in transport network over 41 years (1970-2011) in parts of Bangalore. Thus, the current study shows that the built-up area has been increased drastically, tree cover areas have been converted to agricultural lands and agricultural lands to built-up areas due to urbanization. There are also changes in drainage pattern, transport network and encroachment of water bodies. Thus the whole environment is getting affected adversely due to unplanned and rapid urban sprawl.
Teleportation of Superposition of Coherent States Using 4-Partite States and Effect of Decoherence on Fidelity  [PDF]
H. Prakash, N. Chandra, Shivani A. Kumar, Ranjana Prakash
Journal of Quantum Information Science (JQIS) , 2012, DOI: 10.4236/jqis.2012.24019
Abstract:

A scheme of teleporting a superposition of coherent states |α> and |-α> using a 4-partite state, a beam splitter and two phase shifters was proposed by N. Ba An (Phys. Rev. A, 68, 022321, 2003). The author concluded that the probability for successful teleportation is only 1/4 in the limit |α| and 1/2 in the limit |α|. In this paper it is shown that the author’s scheme can be altered slightly so as to obtain an almost perfect teleportation for an appreciable value of |α|2. We find the minimum assured fidelity i.e., the minimum fidelity for an arbitrarily chosen information state, which we write MAF in this paper, for different cases. We also discuss the effect of decoherence on teleportation fidelity. We find that if no photons are counted in both final outputs, MAF, is still nonzero except when there is no decoherence and the initial state (the state to be teleported) is even coherent state. For non-zero photon counts, MAF decreases with increase in |α|2 for low noise. For high noise, however, it increases, attains a maximum value and then decreases with |α|2. The average fidelity depends appreciably on the initial state for low values of |α|2 only.

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