1. Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/1/6
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Item Effect of fiber weight fraction on mechanical properties of carbon–carbon composites(2012) Naik, Padmayya Shaniyara; Surendranathan A.O.; Londe, Neelakantha V.Item Highly steerable microwave beamforming system near Ku band based on the application of linearly CFBG(Institution of Engineering and Technology, 2020) Raghuwanshi, Sanjeev Kumar; Srivastava, Nimish Kumar; Singh, MandeepIn this study, the authors present theoretical and experimental results of wideband beamforming networks steered by a single linear chirped fibre Bragg grating (CFBG). The standard single-sideband modulation technique is followed to validate the wideband (at 18 GHz) operation of the proposed system. CFBG has been fabricated by phase mask technology for the desired specification to be compatible with the antenna array. To the authors knowledge, the effect of dispersion slope feature of fabricated FBG on the performance of beam-steering capability of the antenna is reported for the first time in this study. Theoretically preceded by experimental testing, it was found that the scanning angle increased with the rise in the number of antenna elements and the frequency of modulating microwave signal.Item Utilization of low computational cost two dimensional analytical equations in optimization of multi rings permanent magnet thrust bearings(2017) Bekinal, S.I.; Doddamani, M.; Dravid, N.D.Replacement of conventional bearings by passive magnetic bearings for high-speed applications, in terms of their performance will be effective, if the design is carried out by optimizing the geometrical dimensions in the given control volume. Present work deals with modification and utilization of two-dimensional (2D) analytical equations in optimization of multi rings permanent magnet (PM) thrust bearing configurations. Conventional and rotational magnetized direction (RMD) configurations are selected in optimizing the design variables for maximum bearing characteristics in a given volume with a constant aspect ratio. The design variables chosen for optimization are axial offset of rotor, number of rings, radial air thickness and inner diameter of the rotor and stator PM rings. MATLAB codes for solving 2D equations are developed in optimizing configuration variables. Further, optimized parameter values of the two configurations are compared. Finally, optimized results obtained using 2D and three-dimensional (3D) equations for the conventional configuration with same aspect ratio are compared, and conclusions are presented. � 2017, Electromagnetics Academy. All rights reserved.Item 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.Item Use of cellulose acetate/polyphenylsulfone derivatives to fabricate ultrafiltration hollow fiber membranes for the removal of arsenic from drinking water(2019) Kumar, M.; RaoT., S.; Isloor, A.M.; Ibrahim, G.P.S.; Inamuddin; Ismail, N.; Ismail, A.F.; Asiri, A.M.Cellulose acetate (CA) and cellulose acetate phthalate (CAP) were used as additives (1 wt%, 3 wt%, and 5 wt%) to prepare polyphenylsulfone (PPSU) hollow fiber membranes. Prepared hollow fiber membranes were characterized by surface morphology using scanning electron microscopy (SEM), surface roughness by atomic force microscopy (AFM), the surface charge of the membrane was analyzed by zeta potential measurement, hydrophilicity by contact angle measurement and the functional groups by fourier transform infrared spectroscopy (FTIR). Fouling resistant nature of the prepared hollow fiber membranes was evaluated by bovine serum albumin (BSA) and molecular weight cutoff was investigated using polyethylene glycol (PEG). By total organic carbon (TOC), the percentage rejection of PEG was found to be 14,489 Da. It was found that the hollow fiber membrane prepared by the addition of 5 wt% of CAP in PPSU confirmed increased arsenic removal from water as compared to hollow fiber membrane prepared by 5 wt% of CA in PPSU. The removal percentages of arsenic with CA-5 and CAP-5 hollow fiber membrane was 34% and 41% with arsenic removal permeability was 44.42 L/m 2 h bar and 40.11 L/m 2 h bar respectively. The increased pure water permeability for CA-5 and CAP-5 hollow fiber membrane was 61.47 L/m 2 h bar and 69.60 L/m 2 h bar, respectively. � 2019 Elsevier B.V.Item 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.Item Use of iron ore mine tailings in infrastructure projects(2019) Shubhananda, Rao, P.; Gayana, B.C.; Ram Chandar, K.Utilisation of iron ore tailings in bricks as a replacement for sand will help in sustainable and greener development. The literature shows the potential use of iron ore tailings as a replacement of natural fine aggregates. As natural sand reserves are depleting day by day, there is a need for substitution for sand in bricks. A comprehensive overview of the published literature on the use of iron ore tailings and other industrial waste is being presented. The effects of various properties such as compressive strength, thermal conductivity and durability of bricks have been presented in this paper. � 2019 Inderscience Enterprises Ltd.Item Unified semi-local convergence for k-Step iterative methods with flexible and frozen linear operator(2018) Argyros, I.K.; George, S.The aim of this article is to present a unified semi-local convergence analysis for a k-step iterative method containing the inverse of a flexible and frozen linear operator for Banach space valued operators. Special choices of the linear operator reduce the method to the Newton-type, Newton's, or Stirling's, or Steffensen's, or other methods. The analysis is based on center, as well as Lipschitz conditions and our idea of the restricted convergence region. This idea defines an at least as small region containing the iterates as before and consequently also a tighter convergence analysis. � 2018 by the authors.Item Unified convergence analysis of frozen Newton-like methods under generalized conditions(2019) Argyros, I.K.; George, S.The objective in this article is to present a unified convergence analysis of frozen Newton-like methods under generalized Lipschitz-type conditions for Banach space valued operators. We also use our new idea of restricted convergence domains, where we find a more precise location, where the iterates lie leading to at least as tight majorizing functions. Consequently, the new convergence criteria are weaker than in earlier works resulting to the expansion of the applicability of these methods. The conditions do not necessarily imply the differentiability of the operator involved. This way our method is suitable for solving equations and systems of equations. Numerical examples complete the presentation of this article. � 2018 Elsevier B.V.Item 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.