Showing papers by "National Institute of Technology, Karnataka published in 2007"
TL;DR: Wettability is a tendency for a liquid to spread on a solid substrate and is generally measured in terms of the angle (contact angle) between the tangent drawn at the triple point between the three phases (solid, liquid and vapour) and the substrate surface.
362 citations
TL;DR: Thirty one new 6-aryl-3-{(4-substituted phenoxy) methyl}-1,2,4-triazolo[3-4-b]-1,3, 4-thiadiazoles (6a-s and 7a-l) and 6- Daryl-3-[( 4- substituting phenoxy methyl]-7H-1.2,2
114 citations
TL;DR: In this article, the authors presented the coastal vulnerability index (CVI) for the estimation of vulnerability of the coastal region of Mangalore coast, India, from Talapady to Surathkal.
Abstract: The paper presents the coastal vulnerability index (CVI) for the estimation of vulnerability of the coastal region of Mangalore coast, India, from Talapady to Surathkal. The CVI is an indication of the relative vulnerability of the various segments of the Mangalore coast to coastal erosion hazards. The following variables are used in the estimation of CVI, which is used to rank the vulnerability of the coastal regions: geomorphology, regional coastal slope, shoreline change rates, and population. The rankings for each variable were combined and an index value calculated for 1′ × 1′ grid cells covering the study area.
105 citations
TL;DR: In this article, the third order nonlinear optical properties of 4′-methoxy chalcone and its derivatives were investigated using a single-beam Z-scan technique with nanosecond laser pulses at 532 nm.
Abstract: The third order nonlinear optical properties of 4′-methoxy chalcone and its derivatives have been investigated using a single-beam Z-scan technique with nanosecond laser pulses at 532 nm. The 4′-methoxy chalcone and its derivatives are donor–acceptor–acceptor (D–A–A) and donor–acceptor–donor (D–A–D) type intramolecular charge transfer molecules. The nonlinear response in these molecules was found to increase with increase in (a) the electron acceptor strength in D–A–A type and (b) the donor strength of the substituted group in D–A–D type molecules. The χ(3) value in these molecules is found to be of the order of 10-13 esu. The observed increase in the third order nonlinearity in these molecules clearly indicates the electronic origin. The compounds exhibit good optical limiting at 532 nm. The best optical limiting behavior was observed with the molecule substituted by a strong electron donor.
99 citations
TL;DR: In this article, an extensive laboratory testing program was carried out to determine the compaction characteristics and hydraulic conductivity of clean and contaminated lateritic soil, which indicated a small reduction in maximum dry density and an increase in hydraulic conductivities due to leachate-contamination.
80 citations
TL;DR: In this article, a symmetric redox supercapacitor has been fabricated based on n and p doped Poly(3,4-ethylenedioxythiophene)(PEDOT) coated on stainless steel (SS) electrodes.
Abstract: A symmetric redox supercapacitor has been fabricated based on n and p doped Poly(3,4-ethylenedioxythiophene)(PEDOT) coated on stainless steel (SS) electrodes. The characterization and performance of the supercapacitor has been studied by FTIR, Cyclic Voltammetry and AC Impedance spectroscopy. The supercapacitor showed a maximum specific capacitance of 121 F g−1 at a scan rate of 10 mV s−1. The time constant calculated for the supercapacitor through the active–reactive power behavior measurement was 12 milliseconds indicating the suitability of the system for efficient use at low frequency range.
56 citations
TL;DR: The performance studies reveal that the pulsed plate bioreactor with immobilized cells has the potential to be an efficientBiodegradation of phenol in a synthetic wastewater containing 500ppm phenol and biofilm density was found to be influenced by pulsation.
47 citations
TL;DR: The optimized attosecond pulse was also the most intense, and its duration of 206 as was very close to the transform-limited value of 200 as.
Abstract: Self-compression of attosecond high-order harmonic pulses in the harmonic generation medium itself has been demonstrated. The attosecond pulses were generated in an argon-filled gas cell and compressed by exploiting the dispersion characteristics of argon. Since the harmonic generation medium itself was used as the compression medium, continuous chirp control was easily achieved by adjusting the gas pressure. The optimized attosecond pulse was also the most intense, and its duration of 206 as was very close to the transform-limited value of 200 as.
43 citations
TL;DR: It was found that, as the dilution rate is increased, the percentage degradation has decreased and steady state percentage degradation was also reduced with increased influent phenol concentration.
42 citations
TL;DR: In this article, the behaviour of the melt treated Al-7Si-Mg alloy (A357) during solidification with or without chilling was investigated using thermal analysis Thermal analysis and heat transfer parameters were determined Thermal analysis parameters were affected significantly by modification and chilling Modification treatment resulted in the increase of cooling rate, heat evolved, casting/mould interfacial heat flux and eutectic growth velocity.
39 citations
26 Jun 2007-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the suitability of vegetable oils such as sunflower, coconut, groundnut, castor, cashewnut shell (CNS), and palm oils as quench media (bioquenchants) for industrial heat treatment by assessing their wetting behavior and severity of quenching was investigated.
Abstract: An investigation was conducted to study the suitability of vegetable oils such as sunflower, coconut, groundnut, castor, cashewnut shell (CNS), and palm oils as quench media (bioquenchants) for industrial heat treatment by assessing their wetting behavior and severity of quenching. The relaxation of contact angle was sharp during the initial stages, and it became gradual as the system approached equilibrium. The equilibrium contact angle decreased with increase in the temperature of the substrate and decrease in the viscosity of the quench medium. A comparison of the relaxation of the contact angle at various temperatures indicated the significant difference in spreading of oils having varying viscosity. The spread activation energy was determined using the Arrhenius type of equation. Oils with higher viscosity resulted in lower cooling rates. The quench severity of various oil media was determined by estimating heat-transfer coefficients using the lumped capacitance method. Activation energy for spreading determined using the wetting behavior of oils at various temperatures was in good agreement with the severity of quenching assessed by cooling curve analysis. A high quench severity is associated with oils having low spread activation energy.
TL;DR: In this article, an analytical formulation and solution for the stress analysis of simply supported antisymmetric angle-ply composite and sandwich plates was presented. But the results were not reported in the literature based on a higher order refined computational model with twelve degrees of freedom.
TL;DR: In this article, the effect of thermal contact heat transfer on the solidification of spherical droplets of four solder alloys, namely, Sn 37Pb, Sn 9Zn, Sn 0.7Cu and Sn 3.5Ag, was studied using SOLIDCAST simulation package.
TL;DR: In this paper, the heat flux transients were estimated by inverse modeling of heat conduction for steel specimens during lateral quenching in brine, water, palm oil and mineral oil.
TL;DR: In this paper, a through-rod-type magneto-rheological (MR) test damper has been designed and fabricated for experimental study, and various factors such as the magnetic field strength, volume fraction of particles in the MR fluid, shearing gap between piston and cylinder, vibration frequency and amplitude, have been considered as input factors, and the root-mean-square (RMS) damping force as the output factor (response variable).
Abstract: In this work, a through-rod-type magneto-rheological (MR) test damper has been designed and fabricated for experimental study. Various factors, such as the magnetic field strength, volume fraction of particles in the MR fluid, shearing gap between piston and cylinder, vibration frequency and amplitude, have been considered as input factors, and the root-mean-square (RMS) damping force as the output factor (response variable). These input factors are varied in two levels (low and high) during the initial phase of experimentation using 25 factorial design; the motivation is to identify the most influential factors. In the second phase of experimentation, the response surface method has been used to identify the modeling equation and to plot the response surfaces. Further, force versus displacement diagrams have been plotted at these factor levels; these give an insight into the damping behaviour of the MR damper.
TL;DR: In this paper, the authors present the results of model scale experiments for the study of wave attenuation by horizontal interlaced, multilayer, moored floating pipe breakwater.
Abstract: The paper presents the results of model scale experiments for the study of wave attenuation by horizontal interlaced, multilayer, moored floating pipe breakwater. A review of some significant floating breakwater models proposed by earlier investigators is included. For a floating breakwater the transmission coefficient ( Kt ) is influenced by relative width of the breakwater (W∕L) . Nondimensional graphs indicating the variation of Kt with respect to W∕L (with Hi ∕L as a parameter for different Hi ∕d values) and Kt versus Hi ∕L (for a range of d∕L values from 0.09 to 0.24) have been plotted. Further variation of Kt with relative depth d∕L for different W∕L values is also studied. From the experimental study and results obtained, it is found that the transmission coefficient decreases with an increase in relative breakwater width W∕L and wave steepness Hi ∕L for all Hi ∕d values. In the present study it was observed that performance was better for breakwater configurations of W∕L⩾0.7 when compared with con...
TL;DR: In this article, the authors investigated the influence on sound level due to drilling in rocks of varying physical properties i.e. compressive strength and abrasivity using a jackhammer drill and found that an increase in thrust increases the sound level at higher midband frequencies in the noise spectrum.
Abstract: An attempt has been made in this paper to investigate the influence on sound level due to drilling in rocks of varying physical properties i.e. compressive strength and abrasivity using jackhammer drill. For this purpose, a jackhammer drill setup was fabricated wherein the thrust applied can be varied while drilling vertical holes. The compressive strength and the abrasivity of various rock samples collected from the field were determined in the laboratory. A set of test conditions were defined for measurement of sound level of the jackhammer drill.Also, with the help of the experimental setup, vertical drilling was carried out on the rock samples for varying thrust and air pressure values and the corresponding A-weighted equivalent continuous sound levels were measured.The results of this study indicate that, increase in thrust increases the sound level at higher midband frequencies in the noise spectrum. The study indicated the sound level near the drill rod to be 0.5 to 1.5 dB, 2.0 to 3.0 dB and 4.0 to 6.0 dB higher relative to that at the drill bit, the exhaust and the operator’s position respectively at an air pressure of 5 kg/cm 2 and 160 N thrust for all the rock samples tested. Both the thrust and air pressure were found to have a significant effect on the sound level produced by jackhammer drill at all the measurement locations. The study further shows that an increase in sound level of the order of 1.5 to 2.5 dB at the operator’s position can occur with an increase in air pressure by 2 kg/cm 2 at 160 N thrust and with an increase in compressive strength and decrease in abrasivity of rocks. Also, the increase in sound level at the operator’s position with increase in compressive strength and decrease in abrasivity of rock is of the order of 1.0 to 2.0 dB. In order to maintain a constant penetration rate in the rocks, both the thrust and air pressure need to be increased with an increase in compressive strength and decrease in rock abrasivity.Therefore,increased compressive strength and lower abrasivity of rocks will require higher air pressure and thrusts to be applied to achieve an optimum penetration rate and therefore will result in higher sound level at the operator’s position and at other measurement locations. © 2007 Institute of Noise Control Engineering.
TL;DR: In this paper, the effect of surface roughness on heat transfer rates in various quenchants was determined by inverse modeling of heat conduction during end quenching of stainless steel probes with three different surfaces roughness (grooved, R a ǫ = 3.0 and 1 µm).
TL;DR: In this article, the synthesis, optical and electrochemical details, and properties of three conjugated copolymers (P1,P3) consisting of alternate hole-transporting thiophene derivative and electron-transport 1,3,4-oxadiazole units are reported.
TL;DR: In this paper, the authors experimentally investigated the armour stone stability of the submerged reef and the influence of its varying distance from shore and crest width on ocean wave transmission, and found that the reef can attenuate the steeper ocean waves, dissipating a major portion of their energy.
12 Jul 2007
TL;DR: This paper presents a novel technique based on Q-learning for replicating objects to other nodes that increases robustness and availability in unstructured peer-to-peer networks.
Abstract: Resource discovery is an important problem in unstructured peer-to-peer networks as there is no centralized index where to search for information about resources. The solution for the problem is to use a search algorithm that locates the resources based on the local information about the network. Efficient data sharing in a peer-to-peer system is complicated by uneven node failure, unreliable network connectivity and limited bandwidth. A well-known technique for improving availability is replication. If multiple copies of data exist on independent nodes, then the chances of at least one copy being accessible are increased. Replication increases robustness. In this paper, we present a novel technique based on Q-learning for replicating objects to other nodes.
TL;DR: This paper investigates some relationships among these four new parameters, which are shown to be the minimum cardinality of an SVC (WVC) and the strong (weak) vertex covering numbers (s@a=<@b=w@b) for any graph G without isolated vertices.
TL;DR: In this article, the authors developed regression models for predicting daily pan evaporation depths from climatic data using three multivariate approaches: multiple least-squares regression (MLR), principal components re...
Abstract: Regression models for predicting daily pan evaporation depths from climatic data were developed using three multivariate approaches: multiple least-squares regression (MLR), principal components re...
TL;DR: A series of new 2]-(4-alkylthio/alkylsulfonyl phenoxy) methyl]-5-substituted-1,3,4-oxadiazoles 4a-y, 5a-h ) have been synthesized from 4-alklythio phenol through a multi-step reaction sequence.
Abstract: A series of new 2-[(4-alkylthio/alkylsulfonyl phenoxy) methyl]-5-substituted-1,3,4-oxadiazoles 4a–y , 5a–h ) have been synthesized from 4-alkylthio phenol ( 1a–b ) through a multi-step reaction sequence. Compounds 1a–b reacted with ethyl chloroacetate to give ethyl [4-(alkylthio) phenoxy] acetate ( 2a–b ) which on oxidation yielded ethyl [4-(alkylsulfonyl)phenoxy]acetate ( 2c–d ). They were readily converted to the corresponding hydrazides 3a–d , and then cyclized to the title compounds 2-{[4-(alkylthio/alkylsulfonyl) phenoxy] methyl}-5-aryl-1,3,4-oxadiazoles ( 4a–y ) by condensing with aromatic carboxylic acids. Further, 3a–b , on condensation with carbon disulphide afforded the title compounds 2-{[4-(alkylthio) phenoxy]methyl}-1,3,4-oxadiazole-5-thiols( 5a–b ), which on alkylation yielded the title compounds 2-[(4-alkylthio phenoxy) methyl]-1,3,4-oxadiazole-5-alkyl thiols ( 5c–f ), while with chloroacetic acid gave the target compounds 2-[(4-alkylthio phenoxy) methyl]-1,3,4-oxadiazole-5-thioacetic acid ...
TL;DR: In this article, the third-order nonlinear optical properties of a newly synthesized soluble copolymer containing oxadiazole and thiophene units were investigated using Z-scan and Degenerate Four Wave Mixing (DFWM) techniques.
TL;DR: In this paper, a self-mated wear test was conducted on three substrate types: HS718, Ti64 and HCHCr substrates, and the results showed that the CrN-TiN system exhibited the best wear behavior, both at room temperature and at 773 K.
TL;DR: In this paper, the synthesis and third-order nonlinear optical (NLO) characterization of two novel copolymers containing alternating 3,4-dialkoxythiophene and 1,4bis(1,3,4oxadiazolyl)benzene units were reported.
Abstract: We report the synthesis and linear and third-order nonlinear optical (NLO) characterization of two novel copolymers containing alternating 3,4-dialkoxythiophene and 1,4-bis(1,3,4-oxadiazolyl)benzene units. The copolymers were synthesized with a precursor polyhydrazide route. Both copolymers exhibited fluorescence around 430 nm under the irradiation of UV light. The NLO measurements were made with the single-beam Z-scan technique with Nd:YAG nanosecond laser pulses at 532 nm. The nonlinear refractive index of the investigated copolymers was negative, and the magnitude was as high as 10−10 esu. The samples exhibited strong reverse saturation absorption and very good optical limiting properties at the wavelength used. The concentration dependence of third-order NLO parameters was studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
13 Dec 2007
TL;DR: This work proposes an algorithm which determines the sequences already existing in the network that are likely to be responsible for the creation of the given sequence.
Abstract: For the construction of a phylogenetic network, it is essential to know if the new sequence that is being inserted is the result of mutations or due to events like recombinations. Recombination is a process of formation of new genetic sequences by piecing together segments of previously existing sequences [1][2]. Once it is determined that it is a recombination process, it is then necessary to determine the number of recombinations required for the generation of this sequence[4]. This is because, in certain cases more than one recombination event are necessary. Here we propose an algorithm which determines the sequences already existing in the network that are likely to be responsible for the creation of the given sequence.
18 Dec 2007
TL;DR: This work presents a new elitist non-dominated sorting-based genetic algorithm (NSGA) called memetic- NSGA which uses the concept of memes, which is a group of genes which have a particular functionality at the phenotype level.
Abstract: In Gene Expression studies, the identification of gene subsets responsible for classifying available samples to two or more classes is an important task. One major difficulty in identifying these gene subsets is the availability of only a few samples compared to the number of genes in the samples. Here we treat this problem as a Multi-objective optimization problem of minimizing the gene subset size and minimizing the number of misclassified samples. We present a new elitist non-dominated sorting-based genetic algorithm (NSGA) called memetic- NSGA which uses the concept of memes. Memes are a group of genes which have a particular functionality at the phenotype level. We have chosen a 50 gene Leukemia dataset to evaluate our algorithm. A comparative study between Memetic-NSGA and another non-dominated sorting genetic algorithm, called NSGA-II, is presented. Memetic-NSGA is found to perform better in terms of execution time and gene-subset length identified.
TL;DR: In this paper, the effects of ball burnishing parameters on the surface hardness of high-strength low alloy steels (HSLA) dual-phase (DP) steel specimens were investigated.
Abstract: Burnishing is used increasingly as a finishing operation which gives additional advantages such as increased hardness, fatigue strength, and wear resistance. Experimental work based on 34 factorial design was carried out to establish the effects of ball burnishing parameters on the surface hardness of high-strength low alloy steels (HSLA) dual-phase (DP) steel specimens. Statistical analysis of the results shows that the speed, feed, lubricant and ball diameter have significant effect on surface hardness.