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Nagaraja D.,Bangalore Institute of Technology | Melavanki R.M.,M.S. Ramaiah Institute of Technology | Patil N.R.,Alagappa Chettiar College of Engineering And Technology | Kusanur R.A.,Rashtreeya Vidyalaya College of Engineering
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

The relative quantum yield of diethyl 2-acetamido-2-((3-oxo-3H-benzo[f] chromen-1-yl)methyl) malonate [2DAM] is estimated using single point method with quinine sulfate as standard reference. The quantum yield varies between 0.1161 and 0.3181 depending on the nature of the solvent. The rates of radiative and non radiative decay constants are also calculated. The fluorescence quenching of [2DAM] by aniline is studied at room temperature, by steady state, in five different solvents namely acetonitrile (AN), 1,4 dioxane (DX), 1,2 dichloroethane (DCE), tetrahydrofuran (THF) and toluene (TOL), in order to explore various possible quenching mechanisms. The experimental results show a positive deviation in Stern Volmer plots for all solvents. Various parameters for the quenching process are determined by ground state complex, sphere of action static quenching model and finite sink approximation model. The magnitudes of these rate parameters indicate that positive deviation in the Stern Volmer (SV) plot is due to both static and dynamic processes. Further, finite sink approximation model is used to check whether these bimolecular reactions were diffusion limited or not. The values of distance parameter R′ and diffusion co efficient D are determined and then compared with the values of encounter distance R and diffusion coefficient D calculated using Stokes-Einstein equation. © 2014 Elsevier B.V. All rights reserved.

Suresh H.N.,Bangalore Institute of Technology
Advances in Intelligent Systems and Computing | Year: 2016

Accomplishing superior version of compression with proper data integrity is a challenging task when it comes to fast intra-prediction for multimedia. We have reviewed various existing techniques of fast intra-prediction mode decision techniques and found a significant trade-off between inequilibrium between compression and signal quality. Hence, we present a novel and simple algorithm that can perform fast intra-prediction mode decision using H.264 standard. The presented paper also uses multiple iterations of enhancement to each prediction model during encoding process considering frame and block sizes. The study also maintains the highest integrity of the meta-data information during frame transition. The outcome of the study is found to outperform the existing similar technique on compression and signal quality. © Springer International Publishing Switzerland 2016.

Shivakumara I.S.,Bangalore University | Dhananjaya M.,Bangalore Institute of Technology | Ng C.-O.,University of Hong Kong
International Journal of Heat and Mass Transfer | Year: 2015

The onset of convective instability in a layer of porous medium saturated by the Oldroyd-B viscoelastic nanofluid heated from below is investigated by incorporating the effects of Brownian diffusion and thermophoresis. The flux of volume fraction of nanoparticles is taken to be zero on the boundaries. The resulting eigenvalue problem is solved numerically using the Galerkin method. The onset of convective instability is oscillatory only if the strain retardation parameter is less than the stress relaxation parameter and also when the strain retardation parameter does not exceed a threshold value which in turn depends on other physical parameters. The oscillatory onset is delayed with increasing strain retardation parameter, while an opposite trend is noticed with increasing stress relaxation parameter. The effect of increasing modified diffusivity ratio, concentration Darcy-Rayleigh number, modified particle density increment and Lewis number is to hasten the onset of stationary and oscillatory convection and also to decrease the ranges of the strain retardation parameter within which oscillatory convection is preferred. © 2015 Elsevier Ltd . All rights reserved.

Nagaraja D.,Bangalore Institute of Technology | Melavanki R.M.,M.S. Ramaiah Institute of Technology | Patil N.R.,Alagappa Chettiar College of Engineering And Technology
Canadian Journal of Physics | Year: 2013

Quenching mechanisms of coumarin derivative 6-bromo-3-[1-(4,5- dicarbomethoxy-1,2,3-triazoloacetyl)]coumarin (6BDTC) were carried out in different solvents using the steady-state method to understand the role of diffusion in the quenching mechanism. The solute was excited by UV radiation of wavelength 360 nm. Various quenching parameters like frequency of encounter, kd; probability of quenching per encounter, p; and quenching rate parameter, kq, were experimentally determined for all solvents. Activation energies of quenching, Ea, were also determined by using the literature values of activation energy of diffusion, Ed. It was found that the values of Ea were less than Ed in all solvents indicating that the quenching reactions are more significantly influenced by material diffusion. © 2013 Published by NRC Research Press.

Suresha B.,Indian National Institute of Engineering | Ravi Kumar B.N.,Bangalore Institute of Technology
Journal of Applied Polymer Science | Year: 2011

An experimental characterization of the abrasive wear behavior of clay and clay plus short carbon fiber filled polyamide66/polypropylene (PA66/PP) nanocomposites has been investigated. Two-body abrasive wear studies were carried out using pin-on-disc wear tester under multi-pass condition against the water proof silicon carbide abrasive paper. It was observed that the clay reinforcement is detrimental to the abrasive wear resistance of PA66/PP blend. A combination of clay and short carbon fiber in PA66/PP blend improved the abrasive wear performance than those of clay filled PA66/PP nanocomposites. Further, on the basis of microscopic observation of the worn surfaces, dominant wear mechanisms were discussed. © 2010 Wiley Periodicals, Inc.

SreeRangaRaju M.N.,Bangalore Institute of Technology | Mungara J.,BTL Institute of Technology and Mgt
Conference Proceedings of the IEEE International Performance, Computing, and Communications Conference | Year: 2010

In this paper, we unified two new algorithms, i.e., to selectively Bordercast the control packets in order to reduce the network load by limiting the number of control packets when ZRP searches for a new route. The second algorithm is proposed to optimize the performance of Query control mechanisms for the Zone Routing Protocol (ZRP) for mobile ad hoc networks for communication on an urban terrain. ZRP proactively maintains routing information for a local neighbourhood (routing zone), while reactively acquiring routes to destinations beyond the routing zone. This hybrid routing approach can be more efficient than traditional Zone Routing Protocol (ZRP) framework. However, without proper query control techniques, the ZRP cannot provide the expected reduction in the control traffic. Our proposed algorithm enhances the structure of the routing zone to provide enhanced detection and prevention of overlapping queries. These techniques can be applied to single or multiple channel mobile adhoc networks to improve both the delay and control traffic performance of ZRP. Our new algorithm allows ZRP to provide routes to all accessible network nodes, with less control traffic than purely proactive link state or purely reactive route discovery, and with less delay than conventional flood searching. The performance evaluation via simulations using a well known simulator QualNet version 5.0 shows that the new approach has better performance than the traditional ZRP. © 2010 IEEE.

Venkatesha N.J.,Bangalore Institute of Technology | Chandrashekara B.M.,Bangalore Institute of Technology | Jai Prakash B.S.,Bangalore Institute of Technology | Bhat Y.S.,Bangalore Institute of Technology
Journal of Molecular Catalysis A: Chemical | Year: 2014

para-Toluene sulphonic acid (p-TSA)-treated montmorillonite clay used as heterogeneous catalyst in acylation of para-cresol (PC) with aliphatic carboxylic acids. Reactions were studied under microwave and conventional modes of heating and reaction conditions were optimized by varying mole ratio, temperature, amount of catalyst and reaction time. Under optimized conditions the reaction was carried out involving p-cresol and decanoic acid. The reaction involved two steps, O-acylation involving ester formation followed by the Fries rearrangement involving C-acylation resulting in ketone product. Microwave heating mode showed higher conversion and the catalytic activity almost retained in repeated use. On the other hand the catalytic activity dropped by more than 50% in the case of conventional heating indicating rapid deactivation. A change in the color of the used catalyst was more intense in the case of conventional than in the microwave heating. Used catalysts were characterized for surface area and pore volume by BET technique, acidity by FTIR spectroscopy and amount of coke by TGA. Further investigations on the catalyst used in conventional heating revealed that the deactivation occurred during the O-acylation and not in the subsequent Fries rearrangement. However, the catalyst in the microwave irradiated reaction, exhibited a retarded rate of formation of coke precursors on the surface during O-acylation, thus preventing any decrease in catalytic activity. Present study indicates that the technique chosen for heating the reaction medium plays an important role in suppressing deactivation. © 2014 Elsevier B.V.

Chandra Shekara B.M.,Bangalore Institute of Technology | Jai Prakash B.S.,Bangalore Institute of Technology | Bhat Y.S.,Bangalore Institute of Technology
Journal of Catalysis | Year: 2012

Solventless liquid-phase acylation of p-cresol with different aliphatic carboxylic acids like acetic, propionic, butyric, hexanoic, octanoic, and decanoic acids was investigated over BEA zeolite under conventional as well as microwave heating. An unanticipated huge difference in activity was observed between two modes of heating. Under conventional heating, conversion of all the acids was less than 20%, while under microwave heating, the conversion was in the range of 50-80%. Ester formed through O-acylation and ortho-hydroxyketone formed through Fries rearrangement of the ester were the only products. Conversion of carboxylic acid increased with chain length up to hexanoic acid and then it showed a decrease in the trend. With all the acids, O-acylation occurred rapidly followed by slow conversion to ortho-hydroxyketone. The ketone/ester ratio increased with catalyst amount, temperature, and reaction time. Used catalyst samples were characterized by TGA, XRD, and IR studies to understand lower activity and deactivation behavior under conventional heating. The results showed absence of coke precursor/coke on the catalyst used in microwave-irradiated reactions in contrast to catalyst used in conventionally heated ones. Higher yield in the case of microwave-assisted reactions is attributed to the prevention of coke precursor/coke on the active sites by microwaves. © 2012 Elsevier Inc. All rights reserved.

Suresha B.,Indian National Institute of Engineering | Ravi Kumar B.N.,Bangalore Institute of Technology | Venkataramareddy M.,Bangalore Institute of Technology | Jayaraju T.,Indian National Institute of Engineering
Materials and Design | Year: 2010

The objectives of this research article is to evaluate the mechanical and tribological properties of polyamide66/polypropylene (PA66/PP) blend, graphite (Gr) filled PA66/PP, nanoclay (NC) filled PA66/PP and NC plus short carbon fiber (NC + SCF) filled PA66/PP composites. All composites were fabricated using a twin screw extruder followed by injection molding. The mechanical properties such as tensile, flexure, and impact strengths were investigated in accordance with ASTM standards. The friction and sliding wear behaviour was studied under dry sliding conditions against hard steel on a pin-on-disc apparatus. Scanning electron micrographs were used to analyze the fracture morphologies. From the experimental investigation, it was found that the presence of NC and SCF fillers improved the hardness of PA66/PP blend. Further, the study reveals that the tensile and flexural strength of NC + SCF filled PA66/PP was higher than that of PA66/PP blend. Inclusion of micro and nanofillers reduced the wear rate of PA66/PP blend. The wear loss of the composites increased with increasing sliding velocity. The lowest wear rate was observed for the blend with nanoclay and SCF fillers. The wear rates of the blends with micro/nanofillers vary from 30-81% and lower than that of PA66/PP blend. The wear resistance of the PA66/PP composites was found to be related to the stability of the transfer film on the counterface. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © 2009 Elsevier Ltd. All rights reserved.

SreeRangaRaju,Bangalore Institute of Technology | Mungara J.,BTL Institute of Technology and Management
European Journal of Scientific Research | Year: 2010

Without any pre-existing fixed network infrastructure with rapid configuration of wireless connections on-the-fly, network topology in MANETs keep on changing rapidly. Thus achieving data transmissions between wireless nodes in MANETs with improved QoS parameters become a challenging issue. To achieve this one has to concentrate on the routing protocol they choose. In our paper we proposed an algorithm to provide improved quality of service via hybrid routing protocol- Zone Routing Protocol (ZRP). We have considered two reactive routing protocols Dynamic Source Routing (DSR) and Ad hoc On Demand Distance Vector (AODV) as reference for analyzing ZRP by considering route acquisition delay and quick route reconfiguration during link failure. These parameters viz., route acquisition delay and quick route reconfiguration have their impact on increase in end to end delay, this automatically decreases the number of packets received thus the throughput. We used well known network simula tor QualNet version 4.5 to compare QoS parameters viz., throughput, number of bytes received, number of packets received, average end-to-end delay and the time at which first packet is been received for DSR, AODV and ZRP. © 2010 EuroJournals Publishing, Inc.

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