Browsing by Author "Rahul, S."

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    A Simple Polynomial Time Algorithm for Max Cut on Laminar Geometric Intersection Graphs
    (Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing, 2022) Joshi, U.; Rahul, S.; Thoppil, J.J.
    In a geometric intersection graph, given a collection of n geometric objects as input, each object corresponds to a vertex and there is an edge between two vertices if and only if the corresponding objects intersect. In this work, we present a somewhat surprising result: a polynomial time algorithm for max cut on laminar geometric intersection graphs. In a laminar geometric intersection graph, if two objects intersect, then one of them will completely lie inside the other. To the best of our knowledge, for max cut this is the first class of (non-trivial) geometric intersection graphs with an exact solution in polynomial time. Our algorithm uses a simple greedy strategy. However, proving its correctness requires non-trivial ideas. Next, we design almost-linear time algorithms (in terms of n) for laminar axis-aligned boxes by combining the properties of laminar objects with vertical ray shooting data structures. Note that the edge-set of the graph is not explicitly given as input; only the n geometric objects are given as input. © Utkarsh Joshi, Saladi Rahul, and Josson Joe Thoppil; licensed under Creative Commons License CC-BY 4.0.
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    Effect of 1,2,3benzotriazole on the corrosion of aged 18Ni250 grade Maraging steel in Phosphoric acid solution
    (2018) Naik, P.; Nayak, J.; Girish, L.V.; Somashekhar, T.M.; Bhanuprakash, S.H.; Rahul, S.
    The 18 Ni 250 grade maraging steel is a potential high strength steel for advanced technologies such as aerospace, nuclear, and sporting goods. Phosphoric acid and Nitric acid solutions are used in pickling of delicate and precision items where re-rusting after pickling has to be avoided. The present work addresses the study of corrosion behaviour and inhibition using 1,2,3 benzotriazole of aged 18 Ni 250 grade maraging steel in phosphoric acid medium at higher concentration by Potentiodynamic Polarization Technique. The corrosion rates were determined in 1M, 1.5M and 2M by Tafel extrapolation technique in the temperature range 300C-500C with different concentrations of inhibitor. The results indicate that the corrosion rate increases with increase in acid concentration and temperature.Inhibition efficiency of 1,2,3benzotriazolewas found to increase with the increase in 1,2,3 benzotriazole concentration and decrease with the increase in temperature.The activation energy Ea and other thermodynamic parameters (?G,?H# and?S#) have been evaluated and discussed. The standard free energy of adsorption?Gads values indicates that the adsorption is of mixed type. Scanning electron microscopy (SEM) study confirmed the formation of an adsorbed protective film on the metal surface. � Published under licence by IOP Publishing Ltd.
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    Effect of 1,2,3benzotriazole on the corrosion of aged 18Ni250 grade Maraging steel in Phosphoric acid solution
    (Institute of Physics Publishing helen.craven@iop.org, 2018) Naik, P.; Nayak, J.; Girish, L.V.; Somashekhar, T.M.; Bhanuprakash, S.H.; Rahul, S.
    The 18 Ni 250 grade maraging steel is a potential high strength steel for advanced technologies such as aerospace, nuclear, and sporting goods. Phosphoric acid and Nitric acid solutions are used in pickling of delicate and precision items where re-rusting after pickling has to be avoided. The present work addresses the study of corrosion behaviour and inhibition using 1,2,3 benzotriazole of aged 18 Ni 250 grade maraging steel in phosphoric acid medium at higher concentration by Potentiodynamic Polarization Technique. The corrosion rates were determined in 1M, 1.5M and 2M by Tafel extrapolation technique in the temperature range 300C-500C with different concentrations of inhibitor. The results indicate that the corrosion rate increases with increase in acid concentration and temperature.Inhibition efficiency of 1,2,3benzotriazolewas found to increase with the increase in 1,2,3 benzotriazole concentration and decrease with the increase in temperature.The activation energy Ea and other thermodynamic parameters (ΔG,ΔH# andΔS#) have been evaluated and discussed. The standard free energy of adsorptionΔGads values indicates that the adsorption is of mixed type. Scanning electron microscopy (SEM) study confirmed the formation of an adsorbed protective film on the metal surface. © Published under licence by IOP Publishing Ltd.