Showing papers by "National Institute of Technology, Karnataka published in 2010"
Proceedings Article•
01 Sep 2010
TL;DR: An algorithm for this optimization problem, as well as a greedy scheme with some performance guarantees for a variant of the problem that seeks to minimize a simpler objective are proposed.
Abstract: A scheme for consensus formation is considered wherein the value of a certain variable associated with the nodes of a network is fixed a priori for a prescribed set of K nodes, and allowed to propagate throughout the network through an averaging process that mimics a gossip algorithm. The objective is to find the best choice of these K nodes that will achieve the fastest convergence to consensus. This objective is captured by the Perron-Frobenius eigenvalue of the resultant sub-stochastic matrix, which then is the quantity one seeks to minimize. We propose an algorithm for this optimization problem, as well as a greedy scheme with some performance guarantees for a variant of the problem that seeks to minimize a simpler objective. Some other related formulations are also considered.
719 citations
TL;DR: Preliminary results indicated that most of the hydrazone derivatives demonstrated very good antibacterial and antituberculosis activities while other derivatives showed moderate activity.
173 citations
TL;DR: In this article, a symmetric (p/p) supercapacitor has been fabricated by making use of nanostructured zinc oxide (ZnO)-activated carbon (AC) composite electrodes for the first time.
Abstract: A symmetrical (p/p) supercapacitor has been fabricated by making use of nanostructured zinc oxide (ZnO)–activated carbon (AC) composite electrodes for the first time. The composites have been characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction analysis (XRD). Electrochemical properties of the prepared nanocomposite electrodes and the supercapacitor have been studied using cyclic voltammetry (CV) and AC impedance spectroscopy in 0.1 M Na 2 SO 4 as electrolyte. The ZnO–AC nanocomposite electrode showed a specific capacitance of 160 F/g for 1:1 composition. The specific capacitance of the electrodes decreased with increase in zinc oxide content. Galvanostatic charge-discharge measurements have been done at various current densities, namely 2, 4, 6 and 7 mA/cm 2 . It has been found that the cells have excellent electrochemical reversibility and capacitive characteristics in 0.1 M Na 2 SO 4 electrolyte. It has also been observed that the specific capacitance is constant up to 500 cycles at all current densities.
145 citations
TL;DR: In this article, the potential use of natural fibers in composite materials, their availability, processing features, mechanical and physical properties, and some of their applications in India are discussed, focusing on the potential application of natural fiber in composite composite materials.
Abstract: This study focuses on the potential use of natural fibers in composite materials, their availability, processing features, mechanical and physical properties, and some of their applications in India.
135 citations
TL;DR: In this paper, a review provides an insight into the capabilities offered by nanocomposites which include smart materials, harder/lighter platforms, new fuel sources and storage as well as novel medical applications.
Abstract: The potential opportunities promised by nanotechnology for enabling advances in defence technologies are staggering. Although these opportunities are likely to be realised over a few decades, many advantages are currently being explored, particularly for defence applications. This review provides an insight into the capabilities offered by nanocomposites which include smart materials, harder/lighter platforms, new fuel sources and storage as well as novel medical applications. It discusses polymer-based nanocomposite materials, nanoscale fillers and provides examples of the actual and potential uses of nanocomposite materials in defence with practical examples.Defence Science Journal, 2010, 60(5), pp.551-563, DOI:http://dx.doi.org/10.14429/dsj.60.578
131 citations
TL;DR: In this article, a ternary alloy was applied to mild steel from acidic baths (pH 3.5) for electrodeposited galvanostatically on mild steel.
Abstract: Zn–Fe, Zn–Ni and Zn–Ni–Fe coatings were electrodeposited galvanostatically on mild steel from acidic baths (pH 3.5) consisted of ZnCl 2 , NiCl 2 , FeCl 2 , gelatin, sulfanilic ( p -aminobenzenesulfonic) acid and ascorbic acid. Cyclic voltammetry showed that the effect of gelatin was more pronounced than that of sulfanilic acid, and that the deposition of the ternary alloy behaved differently from the deposition of the binary alloys. In all three systems, the Faradaic efficiency was higher than 88%, the rate of Zn deposition was heavily influenced by mass-transport limitation at high applied current densities, and the deposition was of anomalous type. For each applied current density, the concentrations of Ni and Fe in the ternary alloy were higher than the corresponding concentrations in the binary alloys. The hardness of Zn–Ni coatings was the highest, while that of Zn–Fe coatings was the lowest. The Zn–Ni–Fe coatings were the smoothest, had distinguished surface morphology, and contained ZnO in the bulk, not just on the surface. The lowest corrosion rate in each alloy system (214, 325 and 26 μm year −1 for Zn–Ni, Zn–Fe and Zn–Ni–Fe, respectively) was characteristic of coatings deposited at 30, 30 and 40 mA cm − 2 , respectively. The higher corrosion resistance of the ternary alloy was also reflected by a higher corrosion potential, a higher impedance and a higher slope of the Mott-Schottky line. The enhanced corrosion behavior of the ternary alloy was thus attributed to its chemical composition, phase content, roughness and the synergistic effect of Ni and Fe on the n -type semiconductor surface film.
126 citations
TL;DR: In this article, the ternary Zn-Ni-Co coating was applied on mild steel from an acidic chloride bath containing p-aminobenzenesulphonic acid (SA) and gelatin.
Abstract: Zn–Ni, Zn–Co and Zn–Ni–Co coatings were electrodeposited on mild steel from an acidic chloride bath containing p-aminobenzenesulphonic acid (SA) and gelatin. These additives changed the phase content in the coatings, most likely as a result of their adsorption at the surface of the cathode. The effect of gelatin was more pronounced than that of SA. The Faradaic efficiency was higher than 90%. As the current density was increased or the bath temperature was decreased, the concentration of the nobler metal in the coating increased. Both concentrations of Ni and Co in the ternary alloy increased as the applied current density was increased. Nickel and cobalt were found to have a synergistic catalytic effect. The thickness of all coatings increased as the applied current density was increased. The hardness increased with current density to a peak value, and then decreased. The rate of Zn deposition was heavily influenced by mass-transport limitation at high applied current densities, while the rates of Ni and Co deposition were not. The anomalous codeposition was explained by the great difference between the exchange current densities of Zn and the iron-group metal. Potentiodynamic polarization scans and electrochemical impedance spectroscopy showed that the corrosion resistance of the ternary Zn–Ni–Co alloy coatings was approximately 10 times higher than that of Zn–Ni and 7 times higher than that of Zn–Co. The improved corrosion resistance of the ternary alloy was attributed to its surface chemistry, phase content, texture, and surface morphology. The ternary Zn–Ni–Co coating may thus replace the conventional Zn–Ni and Zn–Co coatings in a variety of applications.
126 citations
TL;DR: A new series of methanamine derivatives synthesized starting from 4-methoxyaniline through multi-step reactions demonstrated moderate to very good antibacterial and antifungal activities comparable to the first-line drugs.
121 citations
TL;DR: In the present study a series of new 1,3,4-oxadiazole derivatives containing 2-fluoro-4-methoxy moiety were synthesized and revealed significant antibacterial activity against Escherichia coli and Pseudomonas aeruginosa and significant antifungal activity against C. albicans.
120 citations
TL;DR: These newly synthesized compounds were characterized by elemental analyses, I.R, NMR and Mass spectral studies, and many of the molecules were found to be potent.
117 citations
TL;DR: A series of novel 2,4-disubstituted thiazole derivatives containing substituted pyrazole moiety showed significant antibacterial activity against all tested microorganisms.
TL;DR: A new class of fused oxazoloquinoline derivatives was synthesized starting from 2-bromo-1-phenylethanones 1a-b through multi-step reactions and preliminary results indicated that most of the compounds demonstrated very good antibacterial and antituberculosis activities which are comparable with the first line drugs.
TL;DR: In this article, an experimental investigation of the third-order nonlinear optical properties of new poly{2-{5]-3,4-ditetradecyloxy-5-(1,3, 4-oxadiazol-2-yl)thiophen-2yl]-1, 3, 4,oxadiaidiazol]-pyridine} (P) in tetrahydrofuran (THF) solution and in solid poly(methylmethacrylate) (PMMA) matrix, by Z-scan technique is
Abstract: An experimental investigation of the third-order nonlinear optical properties of new poly{2-{5-[3,4-ditetradecyloxy-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-1,3,4-oxadiazol-2-yl}pyridine} (P) in tetrahydrofuran (THF) solution and in solid poly(methylmethacrylate) (PMMA) matrix, by Z-scan technique is reported. The Z-scan traces reveal that the composite films exhibit large negative nonlinear refractive index of the order 10−10 esu. The excited-state absorption cross-section was found to be larger than the ground-state absorption indicating that the operating nonlinear process is reverse saturable absorption (RSA). The new polymer P exhibits good optical power limiting properties in the nanosecond regime in solution and as well in solid PMMA matrix.
TL;DR: A QoS model for QoS aware and business driven web service publishing and selection is defined and a web service selection algorithm is presented, which ranks the functionally similar web services based on the degree of satisfaction of the requester's QoS requirements and preferences.
Abstract: A web service is an interface of the software component that can be accessed by standard Internet protocols. The web service technology enables an application to application communication and interoperability. The increasing number of web service providers throughout the globe have produced numerous web services providing the same or similar functionality. This necessitates the use of tools and techniques to search the suitable services available over the Web. UDDI (universal description, discovery and integration) is the first initiative to find the suitable web services based on the requester's functional demands. However, the requester's requirements may also include non-functional aspects like quality of service (QoS). In this paper, the authors define a QoS model for QoS aware and business driven web service publishing and selection. The authors propose a QoS requirement format for the requesters, to specify their complex demands on QoS for the web service selection. The authors define a tree structure called quality constraint tree (QCT) to represent the requester's variety of requirements on QoS properties having varied preferences. The paper proposes a QoS broker based architecture for web service selection, which facilitates the requesters to specify their QoS requirements to select qualitatively optimal web service. A web service selection algorithm is presented, which ranks the functionally similar web services based on the degree of satisfaction of the requester's QoS requirements and preferences. The paper defines web service provider qualities to distinguish qualitatively competitive web services. The paper also presents the modelling and selection mechanism for the requester's alternative constraints defined on the QoS. The authors implement the QoS broker based system to prove the correctness of the proposed web service selection mechanism.
TL;DR: A series of 26 new quinoline derivatives carrying active pharmacophores has been synthesized and evaluated and exhibited significant minimum inhibition concentrations, when compared with first line drugs isoniazid (INH) and rifampicin (RIF) and could be ideally suited for further modifications to obtain more efficacious compounds in the fight against multi-drug resistant tuberculosis.
TL;DR: In this article, the authors derived the resistances between any two vertices of a wheel and a fan by evaluating determinants of submatrices of the Laplacian matrix.
Abstract: The wheel graph is the join of a single vertex and a cycle, while the fan graph is the join of a single vertex and a path. The resistance distance between any two vertices of a wheel and a fan is obtained. The resistances are related to Fibonacci numbers and generalized Fibonacci numbers. The derivation is based on evaluating determinants of submatrices of the Laplacian matrix. A combinatorial argument is also illustrated. A connection with the problem of squaring a rectangle is described.
TL;DR: In this article, the effect of changes in diameter of the steel tube, wall thickness, and length of the tube on axial load and axial shortening at the ultimate point of circular CFT was investigated.
TL;DR: An efficient, microwave irradiated synthesis of novel chromeno[2,3-b]-pyrimidine derivatives was carried out and few of the compounds are found to be potential antimicrobials.
TL;DR: In this paper, three hydrazones, 2-(4-methylphenoxy)- N ′-[(1E)-(4methylphenyl)methylene]acetohydrazide ((compound-2) and N �-{( 1E)-[4-(dimethylamino)phenyl]methylene}-2-(4ethylphenoxy) acetohydrazides(compound3) were synthesized and their third order nonlinear optical properties were investigated using a single beam z-scan technique with nanosecond laser pulses at 532nm.
Abstract: Three hydrazones, 2-(4-methylphenoxy)- N ′-[(1E)-(4-nitrophenyl)methylene]acetohydrazide (compound-1), 2-(4-methylphenoxy)- N ′-[(1E)-(4-methylphenyl)methylene]acetohydrazide ((compound-2) and N ′-{(1E)-[4-(dimethylamino)phenyl]methylene}-2-(4-ethylphenoxy) acetohydrazide(compound-3) were synthesized and their third order nonlinear optical properties were investigated using a single beam z-scan technique with nanosecond laser pulses at 532 nm. Open aperture data obtained from the three compounds indicates two photon absorption at this wavelength. The nonlinear refractive index n 2 , the nonlinear absorption coefficient β , the magnitude of the effective third order susceptibility χ (3) , the second order hyperpolarizability γ h and the coupling factor ρ have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylidene acetone derivatives. Among the compounds studied, compounds-1 and 3 exhibited the better optical power limiting behaviour at 532 nm. Our studies suggest that compounds-1, 2 and 3 are potential candidates for optical device applications such as optical limiters and optical switches.
TL;DR: FPNT was found to be a potent antioxidant when compared to the standard in DPPH, ABTS radical scavenging assays and lipid peroxidation studies.
TL;DR: In this article, the effect of magnetite content on the dielectric properties of the polymer film at different frequencies from 0.01 to 105 Hz was studied using an electrochemical impedance spectroscopy.
Abstract: Magnetite powders in nanometer size have been synthesized by the hydrothermal process. Various magnetic films of chitosan and the synthesized magnetite nanopowders containing different concentrations of the latter were prepared by ultrasonication route. The X-ray diffraction (XRD) studies and the transmission electron microscopy (TEM) images showed that the synthesized magnetite particles had 80 nm dimensions. The band gap of the composites was evaluated using the UV–visible Spectroscopy. The influence of magnetite content on the magnetic properties of the composite showed a decrease in the saturation magnetization with the decrease in the magnetic content. The effect of magnetite content on the dielectric properties of the polymer film at different frequencies from 0.01 to 105 Hz was studied using an electrochemical impedance spectroscopy. The possible mechanism for the observed electrical properties of the composite films was discussed.
TL;DR: A series of square planar nickel(II) complexes containing N,O donor base ligand, i.e. N-(2-pyridyl)-N′-(5-substituted-salicylidene)hydrazine and triphenylphosphine, have been synthesized and characterized by analytical and spectral methods as discussed by the authors.
18 Nov 2010
TL;DR: In this article, Support Vector Machine (SVM) based methods have been used to classify the electrocardiogram (ECG) arrhythmias and classifying them into one of the arrhythmia groups.
Abstract: In this study, Support Vector Machine (SVM) based methods have been used to classify the electrocardiogram (ECG) arrhythmias. Among various existing SVM methods, three well-known and widely used algorithms one-against-one, one-against-all, and fuzzy decision function are used here to distinguish between the presence and absence of cardiac arrhythmia and classifying them into one of the arrhythmia groups. The various types of arrhythmias in the Cardiac Arrhythmias ECG database chosen from University of California at Irvine (UCI) to train SVM, include ischemie changes (coronary artery disease), old inferior myocardial infarction, sinus bradycardy, right bundle branch block, and others. The results obtained through implementation of all three methods are thus compared as per their accuracy rate in percentages and the performance of the SVM classifier using one-against-all (OAA) method was found to be better than other techniques. ECG arrhythmia data sets are of generally complex nature and SVM based one-against-all method is found to be of vital importance for classification based diagnosing diseases pertaining to abnormal heart beats.
TL;DR: In this paper, a new method of reinforcing the stone columns with vertical nails installed along the circumference of the stone column is suggested for improving the performance of these columns, and the results from a series of laboratory plate load tests carried out in unit cell tanks to investigate the improvement in stiffness, load carrying capacity and resistance to bulging of stone columns installed in soft soils.
Abstract: This paper presents results from a series of laboratory plate load tests carried out in unit cell tanks to investigate the improvement in stiffness, load carrying capacity and resistance to bulging of stone columns installed in soft soils. A new method of reinforcing the stone columns with vertical nails installed along the circumference of the stone column is suggested for improving the performance of these columns. Tests were carried out with two types of loading (1) the entire area in the unit cell tank loaded, to estimate the stiffness of improved ground and (2) only the stone column loaded, to estimate the limiting axial capacity. It is found that stone columns reinforced with vertical nails along the circumference have much higher load carrying capacity and undergo lesser compression and lesser lateral bulging as compared to conventional stone columns. The benefit of vertical circumferential nails increases with increase in the diameter, number and depth of embedment of the nails. The improvement in the performance of stone column was found to be more significant, even with lower area ratio. It is found that reinforcing stone column with vertical circumferential nails at the top portion to a depth equal to three times the diameter of stone columns, will be adequate to prevent the column from excessive bulging and to improve its load carrying capacity substantially.
14 Jun 2010
TL;DR: A conversational agent designed to support collaborative learning interactions between pairs of students is described in which the social capability and goal alignment of the agent are manipulated in order to investigate the impact on student learning outcomes and student perceptions.
Abstract: In this study, we describe a conversational agent designed to support collaborative learning interactions between pairs of students We describe a study in which we independently manipulate the social capability and goal alignment of the agent in order to investigate the impact on student learning outcomes and student perceptions Our results show a significant interaction effect between the two independent variables on student learning outcomes While there are only a few perceived differences related to student satisfaction and tutor performance as evidenced in the questionnaire data, we observe significant differences in student conversational behavior, which offer tentative explanations for the learning outcomes we will investigate in subsequent work.
TL;DR: In this article, the effect of clogging and de-clogging on the permeability of porous friction courses (PFCs) was investigated, and three different clogging materials on PFC mixes prepared using four different aggregate gradations.
Abstract: The clogging of porous friction courses (PFCs) plays a major role in their resulting performance. Clogging occurs due to deposition of external and internal materials, leading to the loss of permeability and drainage characteristics of PFCs. In this study, investigations were conducted to determine the effect of clogging and de-clogging on the permeability of PFC mixes. Tests were conducted to study the effect of three different clogging materials on PFC mixes prepared using four different aggregate gradations. Permeability tests were conducted using the falling-head concept on cylindrical PFC specimens. The influence of the particle size ratios and the effective air voids on the permeability of fresh, clogged and de-clogged PFC specimens was analysed. Experimental results on the permeability observed were compared with those predicted using theoretical models. Although, the theoretical models tend to overestimate the permeability values, statistical analyses indicate good correlations with the observed r...
TL;DR: In this article, the third-order nonlinear optical parameters of Bischalcones embedded in DMF solution and in solid PMMA matrix, by Z-scan technique using nanosecond laser pulse trains at 532 nm.
TL;DR: Cell-associated tannase of Serratia ficaria DTC could be industrially important from the perspective of its activity at broad temperature and pH range, its unusually high activity at pH 8.9 and the temperature optima of the enzyme.
Abstract: Five strains of tannic acid degrading bacteria were isolated and identified by phenotypic characterization. All the five isolates showed cell-associated activity, where as only three showed extracellular activity. Serratia ficaria DTC showing highest cell-associated activity (0.29 U/l) was selected for further shake flask studies. Tannase synthesis was growth associated and reached the peak in the late stationary phase of growth. Organic nitrogen sources enhanced the tannase production. Peak tannase production of 0.56 U/l was recorded in the medium having the initial pH of 6. The pH and temperature optima of the enzyme were found to be 8.9 and 35 degrees , respectively. This is the first report of cell-associated activity in case of bacterial tannase. Cell-associated tannase of Serratia ficaria DTC could be industrially important from the perspective of its activity at broad temperature and pH range, its unusually high activity at pH 8.9.
TL;DR: In this paper, a base-triphenylphosphine complexes catalyzes the oxidation of alcohols to their corresponding carbonyl compounds in presence of hydrogen peroxide in good yields.