45 research outputs found
On ideal sequence covering maps
No full text[EN] In this paper we introduce the concept of ideal sequence covering map which is a generalization of sequence covering map, and investigate some of its properties. The present article contributes to the problem of characterization to the certain images of metric spaces which posed by Y. Tanaka [22], in more general form. The entire investigation is performed in the setting of ideal convergence extending the recent results in [11,15,16].The work of N. Adhikary has been supported by UGC (Ref:1127/(CSIR-UGC NET DEC. 2017)), India.Pal, SK.; Adhikary, N.; Samanta, U. (2019). On ideal sequence covering maps. Applied General Topology. 20(2):363-377. https://doi.org/10.4995/agt.2019.11238SWORD363377202A. Arhangelskii, Some types of factor mappings and the relation between classes of topological spaces, Soviet Math. Dokl. 4 (1963), 1726-1729.J. Chaber, Mappings onto metric spaces, Topology Appl. 14 (1982), 31-42. https://doi.org/10.1016/0166-8641(82)90045-1H. Fast, Sur Ia convergence Statistique, Colloq. Math. 2 (1951), 241-244. https://doi.org/10.4064/cm-2-3-4-241-244S. P. Franklin, Spaces in which sequence suffice, Fund. Math. 57 (1965) 107-115. https://doi.org/10.4064/fm-57-1-107-115J. A. Fridy, On ststistical convergence, Analysis 5 (1985), 301-313. https://doi.org/10.1524/anly.1985.5.4.301P. Kostyrko, T. Salát and W. Wilczynski, -convergence, Real Analysis Exchange 26, no. 2 (2000-2001), 669-686.B. K. Lahiri and P. Das, I and I*-convergence in topological spaces, Math. Bohem. 130 (2005), 153-160.S. Lin, Point-countable Covers and Sequence-covering Mappings (in Chinese), Science Press, Beijing, 2002.F. Lin and S. Lin, On sequence-covering boundary compact maps of metric spaces, Adv. Math. (China) 39, no. 1 (2010), 71-78.F. Lin and S. Lin, Sequence-covering maps on generalized metric spaces, Houston J. Math. 40, no. 3 (2014), 927-943.S. Lin and P. Yan, Sequence-covering maps of metric spaces, Topology Appl. 109 (2001), 301-314. https://doi.org/10.1016/S0166-8641(99)00163-7G. D. Maio and Lj.D.R. Kocinac, Statistical convergence in topology, Topology Appl. 156 (2008), 28-45. https://doi.org/10.1016/j.topol.2008.01.015E. Michael, A quintuple quotient quest, General Topology Appl. 2 (1972), 91-138. https://doi.org/10.1016/0016-660X(72)90040-2T. Nogura and Y. Tanaka, Spaces which contains a copy of Sω or S2 , and their applications, Topology Appl. 30 (1988), 51-62. https://doi.org/10.1016/0166-8641(88)90080-6V. Renukadevi and B. Prakash, On statistically sequentially covering maps, Filomat 31, no. 6 (2017), 1681-1686. https://doi.org/10.2298/FIL1706681RV. Renukadevi and B. Prakash, On statistically sequentially quotient maps, Korean J. Math. 25, no. 1 (2017), 61-70.T. Salát, On statistically convergent sequences of real numbers, Math. Slovaca. 30, no. 2 (1980), 139-150.M. Scheepers, Combinatorics of open covers(I): Ramsey theory, Topology Appl. 69 (1996), 31-62. https://doi.org/10.1016/0166-8641(95)00067-4I. J. Schoenberg, The integrability of certain function and related summability methods Amer. Math. Monthly 66 (1959), 361-375. https://doi.org/10.2307/2308747F. Siwiec, Sequence-covering and countably bi-quotient maps, General Topology Appl. 1 (1971), 143-154. https://doi.org/10.1016/0016-660X(71)90120-6F. Siwiec, Generalizations of the first axiom of countability, Rocky Mountain J. Math. 5 (1975), 1-60. https://doi.org/10.1216/RMJ-1975-5-1-1Y. Tanaka, Point-countable covers and k-networks, Topology Proc. 12 (1987), 327-349.J. E. Vaughan, Discrete sequences of points, Topology Proc. 3 (1978), 237-265.P. F. Yan, S. Lin and S. L. Jiang, Metrizability is preserved by closed sequence-covering maps, Acta Math. Sinica. 47 (2004), 87-90.P. F. Yan and C. Lu, Compact images of spaces with a weaker metric topology, Czech. Math. j. 58, no. 4 (2008), 921-926. https://doi.org/10.1007/s10587-008-0060-5A. Zygmund, Trigonometric Series, Cambridge Univ. Press, Cambridge, UK (1979)
A comparative study between manual vacuum aspiration and electrical suction in first trimester MTP
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Semisolid Processing of A380 Al Alloy Using Cooling Slope
No full textThis study is aimed toward obtaining near spherical microstructural features of Rheocast A380 aluminum alloy. Cooling slope (CS) technique has been used to generate semisolid slurry from the superheated alloy melt. Spherodization of primary grains is the heart of semisolid processing which improves mechanical properties significantly in the parts cast from semisolid state compared to the conventional casting processes. Keeping in view of the desired microstructural morphology, i.e., rosette or spherical shape of primary alpha-Al phase, successive slurry samples have been collected during melt flow and oil quenched to investigate the microstructure evolution mechanism. Conventionally cast A380 Al alloy sample shows dendritic grains surrounded by large eutectic phase whereas finer, near spherical grains have been observed within the cooling slope processed slurry and also in the solidified castings which confirms the effectiveness of semisolid processing of the alloy following cooling slope technique. Grain refiner addition into the alloy melt is found to have favorable effect which leads to the generation of finer primary grains within the slurry with higher degree of sphericity
Phase Field Simulation of Equiaxed Microstructure Formation during Semi-solid Processing of A380 Al Alloy
No full textA phase field modelling approach is implemented in the present study towards simulation of microstructure evolution during cooling slope semi solid slurry generation process of A380 Aluminium alloy. First, experiments are performed to evaluate the number of seeds required within the simulation domain to simulate near spherical microstructure formation, occurs during cooling slope processing of the melt. Subsequently, microstructure evolution is studied employing a phase field method. Simulations are performed to understand the effect of cooling rate on the slurry microstructure. Encouraging results are obtained from the simulation studies which are validated by experimental observations. The results obtained from mesoscopic phase field simulations are grain size, grain density, degree of sphericity of the evolving primary Al phase and the amount of solid fraction present within the slurry at different time frames. Effect of grain refinement also has been studied with an aim of improving the slurry microstructure further. Insight into the process has been obtained from the numerical findings, which are found to be useful for process control
Synthesis of 1,8-dioxooctahydroxanthene C-nucleosides
No full textSince reactions between carbohydrates and cyclic 1,3-dicarbonyl compounds do not produce 1,8-dioxooctahydroxanthenes in general, reaction strategies have been devised to generate new 1,8-dioxooctahydroxanthene C-nucleosides by reacting sugars masked with acid-labile protecting groups and with free hydroxyl groups with 1,3-cyclohexanedione or dimedone. Some of these compounds are more cytotoxic to the cancer cells than against normal fibroblasts
Further Investigations on Weighted Value Sharing and Uniqueness of Meromorphic Functions
No full textIn this short manuscript, we will put some light on the different outcomes
when two non-constant meromorphic functions share a value with prescribed
weight two.Comment: arXiv admin note: text overlap with arXiv:1608.02125 by other author
Studies on die filling of A356 Al alloy and development of a steering knuckle component using rheo pressure die casting system
No full textIn this study, a computational fluid dynamics (CFD) model is developed to investigate die filling of semi solid slurry as part of rheo pressure die casting (RPDC) system. The die filling cavity corresponds to that of an automobile steering knuckle, and the slurry is made of A356 aluminium alloy. The rheological model used in the CFD simulation is determined experimentally. The results obtained from present numerical model includes flow field of the slurry within the die cavity, viscosity evolution, solid fraction distribution, temperature and pressure distribution during solidification within cavity during die filling stage. The main objective of the study is to determine the gating arrangement, pouring temperature, and injection conditions for desirable microstructure and mechanical properties of the developed component. To study the effect of injection conditions on die filling capability of the said alloy slurry, five injection profiles are studied, with a variation in final injection velocity between 2–3.2 m/s. In order to corroborate the findings of the present study, microstructural morphology and structure-property correlation have been studied, primarily in the form of optical microscopy and macro hardness measurements, by obtaining samples from different locations of the solidified component
An approach to optimize FIR filter coefficients using GA, PSO and BAT algorithm and their comparative analysis
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