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Rani V.A.,Institute of Aeronautical Engineering | Kumari Y.B.,Jawaharlal Nehru Technological University
Asian Journal of Chemistry

Green synthesis of (4Z)-4-benzylidene-1-methyl-2-styryl-1H-imidazol-5(4H)-one derivatives have been developed in good yields and tested for their antibacterial activities against Escherichia coli, Providencia aeruginosa, Pseudomonas azotogensis and Baccilus subtillis. Some of the synthesized compounds possess good activity against Escherichia coli and Baccilus Subtillis compared to standard drug streptomycin. Source

Yadav S.,Indian Institute of Technology Bombay | Yamasani P.,Institute of Aeronautical Engineering | Kumar S.,Indian Institute of Technology Bombay
Energy Conversion and Management

In this paper, experimental investigations on micro power generation using thermoelectric modules installed around a microcombustor are studied. The work is aimed at developing a combustion based micro power generator as an alternative to low power density electrochemical batteries. A three step micro-combustor is fabricated with mild-steel as the material. Liquefied petroleum gas (LPG)-air mixture is used as fuel-air mixture to operate the microcombustor. A heating cup is used to increase the heat recirculation from hot combustion products thereby enhancing the flame stability limits. The heating cup is fabricated using aluminum material to obtain uniform temperature distribution for improved power generation at smallest scales. The overall conversion efficiency of the micro power generator has been observed to increase with the number of modules mounted on the micro-combustor system as compared to two and one modules. An overall conversion efficiency of 1.2% for one module, 2.56% for two modules and 4.6% for four module configuration was achieved. The overall conversion efficiency reported in the present work is highest for such small scale combustion based micro power generators in comparison to earlier work reported in the literature. A maximum power of 1.56 and 2.35 W respectively is obtained for two and four module configurations. © 2015 Elsevier Ltd. All rights reserved. Source

Rizwana,Institute of Aeronautical Engineering | Sarah P.,P.A. College

Effect of lower ionic radii (Na and Nd) substitution in A-site on the structure, dielectric, ferroelectric and piezoelectric properties of SrBi 4Ti4O15 (SBT) is investigated in this paper. The samples are prepared by solid state double sintering method and sol gel method based on pechini process. Substitution of smaller ions reduced the dielectric constant and remanent polarization values. But sol gel samples showed good dielectric and ferroelectric properties. A-site substitution has resulted in improved Curie temperature and piezoelectric properties. As a result, Na and Nd modified SBT ceramics are found to be excellent high temperature piezoelectric materials. Copyright © Taylor & Francis Group, LLC. Source

Detailed impedance studies are done on Sr1-2xNaxNdx Bi4Ti4O15 (x = 0, 0.1, 0.2, 0.4 and 0.5) system prepared by both sol gel and solid state method. An effort is made to explain the different mechanisms involved in the conduction mechanism through impedance studies. Grain boundary conduction dominates over the grain conduction. Capacitance is associated with the net polarization of ferroelectric domains. Grain boundaries required higher activation energies for hopping than the grains. Copyright © Taylor & Francis Group, LLC. Source

Budarapu P.R.,Bauhaus University Weimar | Yb S.S.,Institute of Aeronautical Engineering | Javvaji B.,Indian Institute of Science | Mahapatra D.R.,Indian Institute of Science
Frontiers of Structural and Civil Engineering

We propose a method to estimate the natural frequencies of the multi-walled carbon nanotubes (MWCNTs) embedded in an elastic medium. Each of the nested tubes is treated as an individual bar interacting with the adjacent nanotubes through the inter-tube Van der Waals forces. The effect of the elastic medium is introduced through an elastic model. The mathematical model is finally reduced to an eigen value problem and the eigen value problem is solved to arrive at the inter-tube resonances of the MWCNTs. Variation of the natural frequencies with different parameters are studied. The estimated results from the present method are compared with the literature and results are observed to be in close agreement. © 2014 Higher Education Press and Springer-Verlag Berlin Heidelberg. Source

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