Analysis of the time series in the space maser signals

We analyze the data of the observations of the radio sources frequently found in space. They are believed to be the sets of molecular condensations each of which works as a maser, so that the whole set produces a characteristic spectrum. It turns out that in some cases the intensity of one of the components of such spectrum corresponding to a single condensation changes periodically with a period of dozens of minutes or of hours.Comment: 5 pages, 6 figure

Oxygen, nitrogen and sulphide fluxes in the Black Sea

The fluxes and production/consumption rates of oxygen, nitrate, ammonium and sulphide are estimated in the paper utilising results of the 1.5-dimensional stationary model of vertical exchange in the Black Sea (Samodurov & Ivanov, 1998). The profiles of the vertical flux and rate of production/consumption of these substances have revealed a number of intriguing features in the biogeochemical nature of the Black Sea. An approximate redox balance of the counter-fluxes of nitrate and ammonium into the sub-oxic zone has been revealed confirming that intensive denitrification may be the primary loss of nitrogen in the Black Sea. A low ratio of the nitrate stock to the flux of nitrate from the oxycline confirms the possibility of prominent changes in the distribution of nitrate on the time scale of a year. The ratio of the nitrate to oxygen vertical flux has revealed a lack of nitrate in the oxycline above the nitrate maximum. The lateral (related to the "Bosporus plume") flux of oxygen in the layer of the main pycnocline appears to be very important for the existing biogeochemical structure of the Black sea water column being the reason of sulphide consumption inside the anoxic zone and changes in the ammonium-sulphide stoichiometry of the anoxic zone, the primary reason of the existence of the sub-oxic layer and the basic reason of relative stability of the sulphide onset

Ventilation of the Black Sea pycnocline on seasonal and interannual time scales

The paper is a description of temporal variability of winter cooling conditions and estimation of effective cross-isopycnal mixing rates in the Black Sea. Data averaging versus salinity / sigma-t scale was used to filter effects of local dynamics. It is shown that traces of winter mixing events appear well preserved in the temperature-salinity structure, due to the peculiarities of the Black Sea where temperature often acts as a passive tracer with a smaller contribution to density as compared to salinity. Vertical distribution of the magnitudes of temperature oscillations indicates that the convection events have limited effects in modifying the structure of the middle and lower pycnocline on a seasonal time scale. However, long-term fluctuations are well recognised. The magnitudes of the seasonal and long-term temperature fluctuations are comparable only in the upper pycnocline. Three major cooling events can be distinguished from the record of the pycnocline temperature for the past 75 years. The intensive cooling occurred in the late 1920s - early 1930s, early 1950s and late 1980s - early 1990s. Partial renewal of the water of the cold intermediate layer core took place approximately once in two years. The period when convection causes erosion of the pycnocline lasts for only a week. It is shown that a lateral source of heat and salt exists for the upper pycnocline, where it is the cold intermediate water, and for the lower pycnocline, the layer below S@ 20.5, where this lateral source of salt and heat is maintained by disintegrating Bosphorus plume

The tape winding current impact on the motor’s torque curve

The paper presents numerical simulations of the tape winding current impact on the motor’s torque curve. The tape winding is a novel type of a motor’s stator organization, allowing the large current flowing through the winding. Consequently the main flux of the permanent magnets changes. The estimation method of the developed torque dependence over the rotor and stator angular position is shown. Taking into account the control current effect the dependence is deformed, in particular it rotates relatively to the center