16,240 research outputs found

    Peculiarities and variations in the optical spectrum of the post-AGB star V448Lac=IRAS22223+4327

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    Repeated observations with high spectral resolution acquired in 1998-2008 are used to study the temporal behavior of the spectral line profiles and velocity field in the atmosphere and circumstellar envelope of the post-AGB star V448Lac. Asymmetry of the profiles of the strongest absorption lines with low-level excitation potentials less 1eV and time variations of these profiles have been detected, most prominently the profiles of the resonance lines of BaII, YII, LaII, SiII. The peculiarity of these profiles can be explained using a superposition of stellar absorption line and shell emission lines. Emission in the (0;1) 5635A Swan band of the C2 molecule has been detected in the spectrum of V448Lac for the first time. The core of the Halpha line displays radial velocity variations with an amplitude ~8 km/s. Radial velocity variations displayed by weakest metallic lines with lower amplitudes, 1-2 km/s, may be due to atmospheric pulsations. Differential line shifts, 0 -- 8 km/s, have been detected on various dates. The position of the molecular spectrum is stationary in time, indicating a constant expansion velocity of the circumstellar shell, Vexp=15.2 km/s, as derived from the C2 and NaI lines.Comment: 19 pages, 8 figures, 1 tabl

    Common Fixed Point Theorems under Rational Inequality

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    In this paper we establish common fixed point theorems for two pairs of self maps in a complete metric space by using occasionally weakly biased maps satisfying the property (E.A.) using contraction  condition involving rational expressions.  These results partially generalize  Pachpatte [10], Jeong and Rhoades [5] and Kameswari [9]. Keywords: Weakly compatible, occasionally weakly compatible, property (E.A), coincidence point, point of coincidence, common fixed point. AMS (2010) Mathematics Subject Classifications: 47H10

    Design and Implementation of High End Multiple Security Based ATM Monitoring System

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    Design and Implementation of High End Security based ATM Monitoring System is invented as a result of observations made in our real life incidents happening around us. This Implementation deals with prevention of ATM robbery with added high end algorithm to the existing technology found in our society. Whenever ATM theft attempt occurs, vibration produced from the machine will be sensed by attached sensor module to it. A panic switch is another module for additional security. Once Vibration is sensed or panic switch activated, a high alert message will be sent to the nearest police station and Bank Authorities using GSM module and a buzzer beep sound will occur at the same time. This system uses PIC controller based embedded system to process real time data collected using sensor and panic switch module. In addition it also restricts the number of occupiers of the machine to single within the pre defined area. This is achieved by processing 3 dimensional real time IR sensors data using ONE_AT_TIME algorithm

    The eigenspectra of Indian musical drums

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    In a family of drums used in the Indian subcontinent, the circular drum head is made of material of non-uniform density. Remarkably, and in contrast to a circular membrane of uniform density, the low eigenmodes of the non-uniform membrane are harmonic. In this work we model the drum head by a non-uniform membrane whose density varies smoothly between two prescribed values. Using a Fourier-Chebyshev spectral collocation method we obtain the eigenmodes and eigenvalues of the drum head. For a suitable choice of parameters, which we find by optimising a cost function, the eigenspectra obtained from our model are in excellent agreement with experimental values. Our model and the numerical method should find application in numerical sound synthesis

    Raman Spectrum of o-Chloroethylbenzene

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    The evolutionary status of the semiregular variable QYSge

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    Repeated spectroscopic observations made with the 6m telescope of yielded new data on the radial-velocity variability of the anomalous yellow supergiant QYSge. The strongest and most peculiar feature in its spectrum is the complex profile of NaI D lines, which contains a narrow and a very wide emission components. The wide emission component can be seen to extend from -170 to +120 km/s, and at its central part it is cut by an absorption feature, which, in turn, is split into two subcomponents by a narrow (16km/s at r=2.5) emission peak. An analysis of all the Vr values leads us to adopt for the star a systemic velocity of Vr=-21.1 km/s, which corresponds to the position of the narrow emission component of NaI. The locations of emission-line features of NaI D lines are invariable, which point to their formation in regions that are external to the supergiant's photosphere. Differential line shifts of about 10km/s are revealed. The absorption lines in the spectrum of QYSge have a substantial width of FWHM~45 km/s. The method of model atmospheres is used to determine the following parameters: Teff=6250K, lg g=2.0, and microturbulence Vt=4.5km/s. The metallicity of the star is found to be somewhat higher than the solar one with an average overabundance of iron-peak elements of [Met/H]=+0.20. The star is found to be slightly overabundant in carbon and nitrogen, [C/Fe]=+0.25, [N/Fe]=+0.27. The alpha-process elements Mg, Si, and Ca are slightly overabundant [alpha/H]=+0.12. The strong sodium excess, [Na/Fe]=+0.75, is likely to be due to the dredge-up of the matter processed in the NeNa cycle. Heavy elements of the s-process are underabundant relative to the Sun. On the whole, the observed properties of QYSge do not give grounds for including this star into the group of RCrB or RVTau-type type objects.Comment: 29 pages, 8 figures, 4 tables; accepted by Astrophys. Bulleti

    Solitary Dust--Acoustic Waves in a Plasma with Two-Temperature Ions and Distributed Grain Size

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    The propagation of weakly nonlinear dust--acoustic waves in a dusty plasma containing two ion species with different temperatures is explored. The nonlinear equations describing both the quadratic and cubic plasma nonlinearities are derived. It is shown that the properties of dust--acoustic waves depend substantially on the grain size distribution. In particular, for solitary dust--acoustic waves with a positive potential to exist in a plasma with distributed grain size, it is necessary that the difference between the temperatures of two ion species be large that that in the case of unusized grains.Comment: 16 pages, 6 figure
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