Additional Pulsation Research Articles

Asymmetric conditions of semiconductor converters in the system of electric energy supply to civil aviation enterprises

The influence of asymmetric conditions on the quality of electric energy of semiconductor converters is considered. The appearance of additional pulsation in the straightened voltage in converter with direct current cell and low frequency modulation in direct converters of frequency is shown

Discovery of additional pulsation modes in AI Velorum

We analyse 13 394 blue-light photometric observations of the high-amplitude δ Scuti star AI Velorum. These data were obtained for six seasons spanning 38 years. We find that in addition to the well-known fundamental and first-overtone radial modes, two previously undiscovered periodicities are present; one of them was initially suspected by Walraven many years ago. These periodicities are present in every season. A tentative identification in terms of the third and fifth radial overtones is proposed. A non-linear interaction term between one of the new periodicities and the first overtone is present. A fifth mode, intermediate in period between the fundamental and first overtone may also be present. We also find that the period of the first overtone is increasing at a steady rate, but that there is little or no change in the period of the fundamental mode over an interval of more than 50 years.

Additional tangential and normal stress close to the wall in the motion of a two-component flow

Industrial tests of the cleaning of a T-100-130 turbine by a twocomponent condenser flow for sludgy deposits of thickness 0.5-1.2.10/sup -3/ m have been carried out for the operating conditions of water-circulation systems at atomic power plants. The additional pulsations of the tangential and normal stress arising in the deposits under the action of the water-air flow proved sufficient for their destruction. Visual inspection of the system after the tests showed the absence of deposits on the inlet sections of the forward and backward tubes and reduction in thickness of the deposits on the outlet sections to low values: (0.1-0.2) .10/sup -3/ m.

The demise of mode identification in the pulsating DA white dwarf GD 66

view Abstract Citations (9) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The demise of mode identification in the pulsating DA white dwarf GD 66. Fontaine, G. ; Wesemael, F. ; Bergeron, P. ; Lacombe, P. ; Lamontagne, R. ; Saumon, D. Abstract An analysis of new photometric and spectroscopic observations of the pulsating DA white dwarf GD 66 is presented. It is shown that the mode identification suggested by Dolez, Vauclair, and Chevreton (1983) is premature. The photometric data reveal the existence of several additional pulsation frequencies which do not fit with their model. Moreover, the 3.90 mHz peak seen in the Fourier spectrum of their light curve of GD 66 is shown to be an artifact of both insufficient time resolution and rotational splitting of the frequency of the dominant pulsation mode. It is not caused by the presence of an independent (different k value) pulsation mode as suggested. In addition, a comparison of model atmosphere calculations with the spectroscopic observations suggests that the surface gravity of GD 66 is quite normal (log g = 7.7 + 0.4 or - 0.2). This is in conflict with the model of the above authors which further requires a significantly larger surface gravity (log g equal to approximately 8.45) to account for the observed pulsation properties of GD 66. Publication: The Astrophysical Journal Pub Date: July 1985 DOI: 10.1086/163301 Bibcode: 1985ApJ...294..339F Keywords: Astronomical Photometry; Light Curve; Stellar Models; Stellar Oscillations; White Dwarf Stars; Astronomical Spectroscopy; Stellar Atmospheres; Stellar Gravitation; Astrophysics full text sources ADS | data products SIMBAD (1)

Peristaltic flow of a viscous incompressible fluid in a plane channel

This article shows the effect of additional pulsations of liquid flow rate on peristaltic flow in a channel and the formation of zones of eddy flow in it.