1,265 research outputs found

    Ultrasonic velocity measurement of liquids by the dual technique mode

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    Of the various techniques available for the measurement of ultrasonic velocity, !he optical method and interferometric method appear to be most widely used. An experimental set up with a provision to measure ultrasonic velocity both by optical and interferometric method is described in this pape

    Resistance of Some Timbers of Andhra Pradesh Against Marine Borer Attack at Four Ports on India

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    Observations on the underwater durability of thirteen species of times growth in Andhra Pradesh against marine borer attack at four ports of Naval interest are recorded. Intensity of borer attack was found to vary from port to port, maximum observed being at Port Blair, with Goa, Bombay and Visakhapatnam following in that order. Comparison of borer activity in the harbours studies with past observations has revealed that a change in eco-systems may be occurring at Visakhapatnam harbour

    Resistance of Some Timbers of Andaman Islands Against Marine Borer Attack at Five Ports of India

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    Six species of structural timbers grown in Andaman area have been examined for natural resistance to marine wood boring organisms at Bombay, Cochin, Goa, Visakhapatnam and Port Blair. Pterocarpus dalbergeioides(Andaman padauk), has been found to be one of the most suitable timbers comparable with teak in performance. Lagerstroemia hypoleuca(Pyinma), has shown a prolonged life and high degree of durability particularly at Bombay. Some important mechanical properties of these timbers have been compared with that of teak so that they may by considered as substitutes

    Parameterized Algorithms for Graph Partitioning Problems

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    In parameterized complexity, a problem instance (I, k) consists of an input I and an extra parameter k. The parameter k usually a positive integer indicating the size of the solution or the structure of the input. A computational problem is called fixed-parameter tractable (FPT) if there is an algorithm for the problem with time complexity O(f(k).nc ), where f(k) is a function dependent only on the input parameter k, n is the size of the input and c is a constant. The existence of such an algorithm means that the problem is tractable for fixed values of the parameter. In this thesis, we provide parameterized algorithms for the following NP-hard graph partitioning problems: (i) Matching Cut Problem: In an undirected graph, a matching cut is a partition of vertices into two non-empty sets such that the edges across the sets induce a matching. The matching cut problem is the problem of deciding whether a given graph has a matching cut. The Matching Cut problem is expressible in monadic second-order logic (MSOL). The MSOL formulation, together with Courcelle’s theorem implies linear time solvability on graphs with bounded tree-width. However, this approach leads to a running time of f(||ϕ||, t) · n, where ||ϕ|| is the length of the MSOL formula, t is the tree-width of the graph and n is the number of vertices of the graph. The dependency of f(||ϕ||, t) on ||ϕ|| can be as bad as a tower of exponentials. In this thesis we give a single exponential algorithm for the Matching Cut problem with tree-width alone as the parameter. The running time of the algorithm is 2O(t) · n. This answers an open question posed by Kratsch and Le [Theoretical Computer Science, 2016]. We also show the fixed parameter tractability of the Matching Cut problem when parameterized by neighborhood diversity or other structural parameters. (ii) H-Free Coloring Problems: In an undirected graph G for a fixed graph H, the H-Free q-Coloring problem asks to color the vertices of the graph G using at most q colors such that none of the color classes contain H as an induced subgraph. That is every color class is H-free. This is a generalization of the classical q-Coloring problem, which is to color the vertices of the graph using at most q colors such that no pair of adjacent vertices are of the same color. The H-Free Chromatic Number is the minimum number of colors required to H-free color the graph. For a fixed q, the H-Free q-Coloring problem is expressible in monadic secondorder logic (MSOL). The MSOL formulation leads to an algorithm with time complexity f(||ϕ||, t) · n, where ||ϕ|| is the length of the MSOL formula, t is the tree-width of the graph and n is the number of vertices of the graph. In this thesis we present the following explicit combinatorial algorithms for H-Free Coloring problems: • An O(q O(t r ) · n) time algorithm for the general H-Free q-Coloring problem, where r = |V (H)|. • An O(2t+r log t · n) time algorithm for Kr-Free 2-Coloring problem, where Kr is a complete graph on r vertices. The above implies an O(t O(t r ) · n log t) time algorithm to compute the H-Free Chromatic Number for graphs with tree-width at most t. Therefore H-Free Chromatic Number is FPT with respect to tree-width. We also address a variant of H-Free q-Coloring problem which we call H-(Subgraph)Free q-Coloring problem, which is to color the vertices of the graph such that none of the color classes contain H as a subgraph (need not be induced). We present the following algorithms for H-(Subgraph)Free q-Coloring problems. • An O(q O(t r ) · n) time algorithm for the general H-(Subgraph)Free q-Coloring problem, which leads to an O(t O(t r ) · n log t) time algorithm to compute the H- (Subgraph)Free Chromatic Number for graphs with tree-width at most t. • An O(2O(t 2 ) · n) time algorithm for C4-(Subgraph)Free 2-Coloring, where C4 is a cycle on 4 vertices. • An O(2O(t r−2 ) · n) time algorithm for {Kr\e}-(Subgraph)Free 2-Coloring, where Kr\e is a graph obtained by removing an edge from Kr. • An O(2O((tr2 ) r−2 ) · n) time algorithm for Cr-(Subgraph)Free 2-Coloring problem, where Cr is a cycle of length r. (iii) Happy Coloring Problems: In a vertex-colored graph, an edge is happy if its endpoints have the same color. Similarly, a vertex is happy if all its incident edges are happy. we consider the algorithmic aspects of the following Maximum Happy Edges (k-MHE) problem: given a partially k-colored graph G, find an extended full k-coloring of G such that the number of happy edges are maximized. When we want to maximize the number of happy vertices, the problem is known as Maximum Happy Vertices (k-MHV). We show that both k-MHE and k-MHV admit polynomial-time algorithms for trees. We show that k-MHE admits a kernel of size k + `, where ` is the natural parameter, the number of happy edges. We show the hardness of k-MHE and k-MHV for some special graphs such as split graphs and bipartite graphs. We show that both k-MHE and k-MHV are tractable for graphs with bounded tree-width and graphs with bounded neighborhood diversity. vii In the last part of the thesis we present an algorithm for the Replacement Paths Problem which is defined as follows: Let G (|V (G)| = n and |E(G)| = m) be an undirected graph with positive edge weights. Let PG(s, t) be a shortest s − t path in G. Let l be the number of edges in PG(s, t). The Edge Replacement Path problem is to compute a shortest s − t path in G\{e}, for every edge e in PG(s, t). The Node Replacement Path problem is to compute a shortest s−t path in G\{v}, for every vertex v in PG(s, t). We present an O(TSP T (G) + m + l 2 ) time and O(m + l 2 ) space algorithm for both the problems, where TSP T (G) is the asymptotic time to compute a single source shortest path tree in G. The proposed algorithm is simple and easy to implement

    Serological diagnosis of pulmonary aspergillosis

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    Methods for the preparation of antigens from clinically isolated cultures of Aspergillus were standardized. Sera from 25 suspected cases of pulmonary aspergillosis were tested against antigens prepared by us, from 4 strains of A. fumigatus and one strain of A. flavus, using the Ouchterlony double diffusion and immunoelectrophoretic techniques. Of the 25 sera tested, 18 reacted positively with antigens of A.fumigatus, one with A.flavus and 2 with both these species. Antigens of two non-pathogenic Aspergilli included in the study failed to react with any of the sera. Our antigen preparations gave more numerous as well as sharper precipitin lines than the commercial Bencard antigens which were used for comparison. Moreover, mycelial antigens from 48 to 96 h old cultures revealed precipitin lines comparable to that of the routine, 4 week old culture filtrate antigens, thus suggesting that the incubation period for obtaining antigens could be cut down considerably

    Credit policy and credit appraisal of canara bank using ratio analysis

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    Credit appraisal is an important activity carried out by the credit department of the bank to determine whether to accept or reject the proposal for finance. The article deals in banking such as working capital and its management, working capital methods of assessment, compilation of credit reports. The study included working capital, working capital cycle and working capital management of Canara Bank. The methods that are used by the banks in order to calculate the loan limits are Turnover method, MBPF system and Cash budget system. The financial statements were taken for a period of five years from 1st April 2007 to 31st March 2012. The Profit and loss account and Balance sheet were analyzed. The firm’s financial performance is analyzed through ratio analyses. The study shows Canara bank has sound system for credit appraisal and the bank has good parameters to appraise the project

    Effect of soaking time and concentration of NaOH solution on mechanical properties of coir-polyester composites

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    The green husk coir fibres were treated with different levels of soaking time and concentration of alkali solution. As a result of alkali treatment, the surface modifications were done on the fibre surface and were studied using scanning electron micrographs. The coir–polyester composites were fabricated using hand lay up process and the mechanical properties (tensile, flexural and impact strength) were evaluated as per ASTM standards. The effect of soaking time and concentration of NaOH solution were studied based on evaluated values of mechanical properties to find out optimum fibre treatment parameters

    Contactless digital tachometer using microcontroller

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    Tachometer is a device that used for counting or for the measuring purpose of the number of revolutions (that is the total number rotations made by the device in unit of measuring time) of an object in unit time. It is expressed in the unit of RPS or RPM, the model uses a set of infrared transducer receiver to count the RPM pulses, and the Arduino microcontroller is used for the implementation of the project. The individual pulses are counted by the microcontroller to give the final output of the RPM
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