1. Journal Articles

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    Aqueous corrosion behaviour of ductile iron and ductile iron containing 1 wt. pct. chromium
    (1997) Surendranathan A.O.; Hebbar, K.R.; Sudhaker Nayak, H.V.
    Ductile irons with graphite in spheroidal form enjoy the processing characteristics of grey iron and mechanical properties of steel. This paper describes the corrosion behaviour of ductile iron containing 1 wt. % chromium in sea water, dilute sulphuric acid and dilute sodium hydroxide solutions and compares with that of unalloyed ductile iron. Study is made in as-cast, annealed and cold worked (upto 28% reduction in thickness) conditions at three different temperatures. Since the alloying addition brings changes in the proportion of phases, the corrosion behaviour of the two materials studied were different, though alloying addition is small, indicating corrosion behaviour to be structure sensitive.
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    Use of mining and seismological parameters as premonitors of rockbursts
    (1997) Srinivasan, C.; Arora, S.K.; Yaji, R.K.
    Comprising one of the deepest mines in the world, the gold mining region of the Kolar Gold Fields (KGF) in southern India is known to be confronted with the acute problem of rockbursts that pose a hazard to workmen and cause disruptions in the production schedule. In combination with mining parameters, seismological data of these rockbursts events systematically monitored over the years using a regional seismic network have been employed to examine and model premonitory characteristics of the events. Linear empirical relations are established relying on correlations seen between the seismic energy released due to a rockburst, total tonnage of ore mined out and total number of rockbursts, as well as seismic events in some shallow and deep workings currently active at KGF. The deterministic model, although not free from certain limitations at present, has been applied to predict rockburst activity with some success. � 1997 Elsevier Science Ltd.
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    Use of inclined compound triangular notch-weir to improve discharge range
    (2009) Shivapur, A.V.; Mulangi, R.H.; Govardhan, Swamy, H.S.
    The notch-weir having simple geometric shapes is unable to measure small as well as occasional large flows. In such situation compound weirs find application. In the present paper authors have reported their study on the use inclined compound notch-weir consisting of two triangular sections with different vertex angles. The notch plane is placed inclined to the general flow surface in the channel. The general discharge equation has been evolved through the semi analytical cum experimental procedure. Results show a significant improvement in discharging rate compared to normal weir. The lower triangular portion of the notch-weir handles the smaller flow whereas the upper part helps to measures the occasional high flows. Further advantages of the inclined compound weir in reducing afflux near the structure are also discussed. � 2009 Taylor & Francis Group, LLC.
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    Unslotted multichannel channel-access protocol for distributed direct-sequence networks
    (2004) Raghavan, A.R.; Baum, C.W.
    A multichannel reservation-based channel-access protocol is investigated in this paper. The available system bandwidth is divided into distinct frequency channels. Under the protocol, one channel (the control channel) is used to exchange reservation messages and the remaining channels (the traffic channels) are used for information-bearing traffic. The performance of this scheme is compared to that of a single-channel reservation-based protocol. A simple contention-based slotted-Aloha protocol is also considered. Performance results take into account the effects of multiple-access interference on acquisition and packet errors. Results show that the reservation-based approach is advantageous under conditions of high traffic. In addition, a pacing mechanism that mitigates multiple-access interference and promotes fairness is described, and results are presented that demonstrate its effectiveness.
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    Unsteady 2-D flow field characteristics for perforated plates with a splitter
    (2004) Yaragal, S.C.
    Wind tunnel experiments were conducted under highly turbulent and disturbed flow conditions over a solid/perforated plate with a long splitter plate in its plane of symmetry. The effect of varied level of perforation of the normal plate on fluctuating velocities and fluctuating pressures measured across and along the separation bubble was studied. The different perforation levels of the normal plate; that is 0%, 10%, 20%, 30%, 40% and 50% are studied. The Reynolds number based on step height was varied from 4�103 to 1.2�104. The shape and size of the bubble vary with different perforation level of the normal plate that is to say the bubble is reduced both in height and length up to 30% perforation level. For higher perforation of the normal plate, bubble is completely swept out. The peak turbulence value occurs around 0.7 to 0.8 times the reattachment length. The turbulence intensity values are highest for the case of solid normal plate (bleed air is absent) and are lowest for the case of 50% perforation of. the normal plate (bleed air is maximum in the present study). From the analysis of data it is observed that ?u?2/(?u?2), (the ratio of RMS velocity fluctuation to maximum RMS velocity fluctuation), is uniquely related with dimensionless distance y/Y?, (the ratio of distance normal to splitter plate to the distance where RMS velocity fluctuation is half its maximum value) for all the perforated normal plates. It is interesting to note that for 50% perforation of the normal plate, the RMS pressure fluctuation in the flow field gets reduced to around 60% as compared to that for solid normal plate. Analysis of the results show that the ratio [C?p max /-Cpb(1 - ?n)], where C?p max is the maximum coefficient of fluctuating pressure, Cpb is the coefficient of base pressure and ?n is the perforation level (ratio of open to total area), for surface RMS pressure fluctuation levels seems to be constant and has value of about 0.22. Similar analysis show that the ratio [C?p max /-Cpb(1 - ?n)] for flow field RMS pressure fluctuation levels seems to be constant and has a value of about 0.32.
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    �ber den Einflu� von Schwefelwasserstoff auf die Korrosion des Eisens in sauren L�sungen
    (1979) Ramchandran, T.; Bohnenkamp, K.
    An Eisenelektroden wurden in anges�uerten Perchlorat und Sulfatl�sungen nach Einleiten von Schwefelwasserstoff erheblich ver�nderte Stromdichte?Potentialkurven beobachtet. Gegen�ber den reinen L�sungen ergeben sich mit Schwefelwasserstoff stark erh�hte anodische Stromdichten und bis um den Faktor 10 erh�hte Korrosionsgeschwindigkeiten. Dabei sind die anodischen Tafelgeraden log iA = f (E) mit H2S nur rund halb so steil wie ohne H2S. Wahrscheinlich wirken die SH??Ionen �hnlich wie die OH??Ionen als Katalysator der Eisenaufl�sung, sind aber bis fast zur S�ttigung absorbiert. Copyright � 1979 Verlag GmbH & Co. KGaA, Weinheim
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    Ultrafast nonlinear optical properties of dye-doped PMMA discs irradiated by 40 fs laser pulses
    (2009) Xia, Y.; Jiang, Y.; Fan, R.; Dong, Z.; Zhao, W.; Chen, D.; Umesh, G.
    The two-photon absorption (TPA) characteristics of PMMA discs doped with three different dyes were studied using an fs-pulsed Ti-Sapphire laser as the pump source, and employing the open-aperture Z-scan technique. TPA cross-sections obtained for PMMA doped with the dyes PM597, DCM and rhodamine 6G-rhodamine B (co-doped) were found to be equal to 24.7, 33.3 and 32.3 GM, respectively (1 GM=10-50 cm4 s phot-1 mol-1). Furthermore, two-photon fluorescence was measured for the samples containing DCM and rhodamine 6G-rhodamine B (co-doped). Compared to the one-photon fluorescence spectrum, the peaks in the two-photon fluorescence spectrum were red shifted and the extent of red shift increased with increasing doping concentration. We have also observed that the red shift in the two-photon fluorescence peak of the samples in the solid form is much larger than that in the solution state. This phenomenon could be explained by a twisted intra-molecular charge transfer model. � 2009 Elsevier Ltd. All rights reserved.
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    TWO-STAGE SEQUENTIALLY OPERATED REGENERATIVE CONVERTERS WITH CONTROLLED FLYWHEELING.
    (1985) Bhat, Subbanna, P.; Dubey, Gopal, K.
    Separately excited dc motors fed by sequentially operated multistage converters are commonly used in mainline traction. The drive performance can be greatly improved by operating the fully controlled converters with controlled flywheeling. The analysis and performance of a dc drive fed by two-stage sequentially operated fully controlled converters with controlled flywheeling are described. The modes of operation of the converter system are identified, and a method for calculating performance, taking these modes of operation into account, is presented. The nomograms and an analytical method of calculating them are presented for computing the optimum value of filter inductance. The performance of the drive with controlled flywheeling is compared with performance using normal control. The modes of operation and certain aspects of drive performance are verified experimentally.
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    Topological energy-function analysis of stability of power systems
    (1987) Padiyar, K.R.; Sastry, H.S.Y.
    In this paper the direct stability evaluation of power systems, with voltage-dependent loads, using topological energy function is given with applications. This is based on the philosophy of a structure-preserving model for power systems. The loads are modelled as arbitrary functions of respectively bus voltages. A classical model is assumed for generators and system equations are formed using centre of angle (COA) reference. A topological energy function is developed and applied for the stability evaluation using the potential-energy boundary surface (PEBS) method. Examples of a 4-machine and a 7-machine system are considered for illustration. The critical clearing time (Tcr) is obtained both by digital simulation and by the direct method for various load characteristics and for different fault locations. � 1987.
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    Trifluoromethyl-quinolin-yl-thio-propanohydrazide as an effective inhibitor of mild steel corrosion in HCl solution
    (2006) Ramesh, Saliyan, V.; Adhikari, A.V.
    3-{[8-(trifluoromethyl)quinolin-4-yl]thio}propanohydrazide(TFQTPH) was synthesized, characterized and tested as a corrosion inhibitor for mild steel in 1 M HCl and 2 M HCl solution using different techniques: potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that TFQTPH is an excellent inhibitor for mild steel in acid medium. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. In the temperature range 20� to 60� C, the TFQTPH adsorption follows Langmuir isotherm model. The protection efficiency increased with increasing inhibitor concentration (10 to 500 ppm), even at higher temperature also, it recorded good inhibition efficiency. � 2006 SAEST.