Reflection of large-scale inhomogeneities in the air-sea boundary layer on the intensity of surface wave breaking in the ocean

An overview of experiments is given on the observation of the dependence of the intensity of wind wave breaking on large-scale currents' inhomogeneities and atmospheric boundary layer stratification. The data were interpreted using a model in which the variance of the wind wave breaking intensity reflects fluctuations in the influx of energy to wind waves due to various factors. Translated by V. Puchkin.     

Calculation of the nonlinear energy transfer through the wave spectrum at the sea surface covered with broken ice

The nonlinear energy transfer through the wave spectrum is studied on the basis of the previously obtained explicit equation for matrix elements of a four-wave kinetic integral. The equation describes the evolution of a system of gravity waves at the surface of a sea of finite depth with a uniform distribution of broken ice over the sea surface. Particular attention is paid to the analytical part of the algorithm of the calculation of the kinetic integral. This part differs from the standard algorithm by a set of prominent features of the dispersion relation for wave oscillations in the ice-covered water. The kinetic integral for the system under consideration is calculated, and the results are compared with the results obtained for the ice-free water.     

A comparative study of the breathing and clearing characteristics of different types of snorkels

This article presents a comparative study of the breathing resistance and clearing characteristics of several types of commercially available snorkels in an attempt to device quantitative means that enable the divers to select the best snorkel and the designers to see the possible directions and modifications necessary for improving the performance of such important life support devices.Two test stands have therefore been built, the first to measure the breathing resistance and the second to monitor the clearing efficiency and speed of some of the commonly used snorkels.The tested snorkels varied from the simple J-type to the sophisticated wrap-around snorkels with convoluted flexible hoses and flared ends.The results obtained show that large diameter snorkels of the wrap-around design with sweeping barrels and flared ends (as the AMF Swimmaster snorkel number 2S55) offer the least breathing resistance. As for the clearing characteristics snorkels with small diameters and of the simple J-type (as the Spanish Aquasub snorkel: The Canarias) or with large diameters and sweeping barrels (as the Power Tuned snorkel of U.S. divers) possess the best clearing figure of merit.     

Photometry of the bright stars inside and outside associations in the spiral arm S5 of the andromeda galaxy

Photometry of more than 1000 bright stars of 20 associations and some fields in its vicinity is made, usingUBV plates taken with a 2-m Ritchey-Chrétien telescope of the National Observatory at the Bulgarian Academy of Sciences with limited magnitudes of about 20.6 inU andV, 21.6 inB. The colour-magnitudes of about 20.6 inU andV, 21.6 inB. The colour-magnitude and colour-colour diagrams of 12 associations and 8 fields are constructed and the brightest blue and red stars colour excesses, ages, and integrated luminosities of the associations are determined. The composite diagrams for all association and nonassociation measured stars are constructed too. Inside associations bright stars as well as non-stellar objects occur more often than outside. The brightest stars in S5 are withM _v7 and do not differ considerably from the brightest ones in the spiral arm S4 of M31. Approximately the same are the absolute magnitudes of the brightest stars in our Galaxy and M33. A small difference between the brightest stars of the latter galaxy with those of M31 is possible because the stars in M33 are younger. This is in agreement with the concept that Sc galaxies (for example M33) are younger than Sb ones (for example M31). The same could be the reason for the smaller ratio of blue to red supergiants in M33 than in M31. The age estimations of the associations in S5 together with those in S4 in M31 show that they are older than the associations in M33 which is in agreement with the above mentioned concept.     

Testing for quantized redshifts. I. The project

A project intended to examine the long-standing claims that extragalactic redshifts are periodic or quantized was initiated some years ago at the Royal Observatory, Edinburgh. The approach taken is outlined, and the main conclusions to date are summarized. The existence of a galactocentric redshift quantization is confirmed at a high confidence level.     

Photometric investigation of the evolved contact binary system DN Aur

We present here the photometric light curve analyses of the eclipsing binary star DN Aur. The CCD photometry, performed at the Behlen observatory using the 0.76 m automated telescope gave 646 individual data points inV andR bandpass filters. From this data we have determined a new epoch and an orbital period of 0.6168891 days. The published spectral classification is F3.The Wilson-Devinney model was used to derive the photometric solutions. DN Aur is a W UMa type contact binary system. The mass ratio, (q=m ₂/m ₁0.210, where star 2 is eclipsed at the primary minimum) suggests that the system has A-type configuration. The computed light curve has a third light of about 22 percent and a total eclipse in the secondary minimum. A solution with a cool spot on the secondary component is also found. We recommend spectroscopic study of DN Aur even though the light curve analysis show it to be a single line spectroscopic system. Generally contact systems of spectral type F3 have periods ranging from 0.25 to 0.5 days. The longer period of DN Aur suggests that it is an evolved contact system with case A mass transfer.     

Simulation of large-scale gas structures formed in the interaction between galaxies. I. Method and preliminary results

Computer programs developed to study large-scale, transient gas structures in galaxies are described and test results are given. Gas-dynamic quantities are determined on the basis of a three-dimensional algorithm using so-called "smoothed particle hydrodynamics" (SPH). Preliminary calculations were made to simulate the formation of a gas ring around a spheroidal galaxy when it absorbs a low-mass, gas-rich companion, as well due to gas accretion during the flyby of a spiral galaxy of comparable mass. The evolution of tidal gas tails of disk galaxies is investigated.Translated from Astrofizika, Vol. 39, No. 2, pp. 265–284, April–June, 1996.     

A filament eruption and accompanying coronal field changes on November 5, 1992

An H filament eruption on November 5, 1992 was fully observed in H with the Hida Flare Monitoring Telescope, while Yohkoh's Soft X-ray Telescope observed the pre- and post-eruption evolution of the coronal magnetic fields. From the H data, including the red and blue wings, we have reconstructed the rise of the filament, including trajectory, velocity, and acceleration. In combination with the Yohkoh data this reconstruction suggests that the filament had several interactions with other coronal magnetic fields during the eruption. The Yohkoh data also shows pre-eruption changes in the coronal fields and several post-eruption bright coronal structures. The pre-eruption changes are interpreted as a partial opening of the corona, indicating that it is not necessary to have a complete opening of the corona in order for a filament to erupt and we discuss the several possible contributions from emerging flux. The post-event bright coronal structures are compared with theory and with a cleaner filament eruption event on July 31, 1992. These comparisons suggest that, although there are many similarities, it is hard to completely reconcile the observations with the existing theory.