Revision of the photometric parameters of BS Cassiopeiae

Seven charge-coupled device(CCD)photometric times of light minimum of the overcontact binary BS Cas which were obtained from 2007 August to November and one CCD light curve in the R band which was observed on 2007 September 24 and October 15,are presented.It is found that the light curve of BS Cas has characteristics like a typical EW-type light variation.The light curve obtained by us is symmetric and shows total eclipses,which is very useful for determining photometric parameters with high precision.Photometric solutions were derived by using the 2003 version of the Wilson-Devinney code.It shows that BS Cas is a W-subtype overcontact binary(f = 27.5% ± 0.4%)with a mass ratio of q = 2.7188 ± 0.0040.The temperature difference between the two components is 190 K.Analysis of the O-C curve suggests that the period of AE Phe shows a long-term continuous decrease at a rate of dP/dt=-2.45 × 10-7 dyr-1.The long-time period decrease can be explained by mass transfer from the primary to the secondary.     

The computation of the elastic constants of an anisotropic medium from the velocities of body waves

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Dedicated to 90th Birthday of Professor Frantiek Fiala     

Colour schlieren representation of compressional-stress fields with respect to focal zone study

Summary A method of colour schlieren recording of the compressional-stress field gradients, suitable for focal zone study on models, is suggested. The study presents colour schlieren records of the compressional-stress fields in loaded square plates, containing inhomogeneities which give instant quantitative information on these fields. If the inhomogeneity is shaped like Griffith's diagonal slit, good agreement is demonstrated between the experiment and the theoretical calculation of the compressional-stress field in a model.     

Evolutionary stages of the Banská Stiavnica caldera and its post-volcanic structures

The remains of an extensive volcanic apparatus of the Tertiary « subsequent » volcanism have been identified in the ?tiavnické pohoric Mts. in the inner belt of the Carpathians. The volcanic apparatus, of stratovolcanic type, was formed during several stages of andesitic and rhyolitic volcanism with two caldera stages. During the final stage of volcanic activity the central collapsed area was uplifted as a horst, accompanied by the formation of grabens along the periphery of the central updomed area. The fractured zones of the horst periphery, as well as zones bordering separate subsided blocks of the central area became the sites of economic ore mineralization, with the formation of lead, zinc, copper, gold, and silver bearing veins. In the uplifted central block intrusions of diorite and granodiorite in the pre-volcanic basement have been exposed by erosion. Geological, petrographical, and petrochemical criteria, as well as absolute dating indicate direct chronological and genetic relationships between the diorite-granodiorite intrusions and extrusive volcanism.     

Correction of the level of magnification of the SVK vertical seismograph at the seismic station of průhonice (PRU)

Summary Drawing on the results of new measurements of the mechanical parameters of the SVK seismometer No. 5055, the level of magnification of the vertical seismograph used in the past, has been corrected. The amplitudes of the seismic waves from earthquakes in the period 1963–1978 have to be increased by 88% and the station correction for determining the magnitudes of earthquakes decreased by 0.274.     

Amplitude curves ofP waves for the region of central Asia

Summary The amplitude-distance curves of P waves, valid for the region of Central Asia, were derived in the distance range between 13° and 36° using observations of a network of eight Caucasian seismic stations. The curves are characterized by an anomalous increase of amplitudes between 13° and 20° followed by a large decrease of amplitudes in the distance range between 20° and 35°. Both the increase and decrease of amplitudes are interrupted by several local maxima. A comparison of the present amplitude curves with those derived for the regions of South-Eastern Europe and Asia Minor enabled us to correlate the individual local maxima of amplitude curves and to investigate the variation of their position due to the lateral inhomogeneity of the upper mantle structure in Eurasia.A. Tskhakaya deceased in 1970.     

ДИНАМИЧЕСКИЕ ПАРАМЕТРЫ СИЛЬНЫШ ЗЕМЛЕТРЯСЕНИЙ ПО ДАННЫМ ШИРОКОПОЛОСНОЙ ДЛИННОПЕРИОДНОЙ АППАРАТУРЫ

Summary The dynamic focal parameters of a series of strong earthquakes, recorded by the FBV broadband velocigraph at KHC (Kaperské Hory, Czechoslovakia), are estimated. The influence of specific wave pattern features on the estimation accuracy is studied. Polarization analysis is used to demonstrate the complicated interference character even of record portions corresponding to a single teleseismic wave group. The values of the dynamic focal parameters do not depend significantly on the length of the analysed record portions and are sufficiently consistent with those reported by Riznichenko [2]. The possibility of estimating dynamic focal parameters from recording of standard classes B (intermediate band) and C (long-period) seismographs is pointed out.     

Tensional crack development in physical models with inhomogeneities under load

Summary The paper deals with a study of the mean stress field (_M) and its gradient (_M/x) in uniaxially loaded two-dimensional models of small thickness with respect to other dimensions, in which two inhomogeneities, e.g., a circular opening and a linear slit have been made. Particular attention was paid to the stress field development in the treated models durin gthe change of the mutual geometric configuration of both the inhomogeneities in question. The problem was analysed theoretically by means of Muskhelishvili's potentials of the two-dimensional theory of elasticity. To compare the results of calculations, the schlieren method was used to visualize and record the studied gradients of stress fields in physical models. The results of the calculations were calibrated by laboratory tests. In this way the individual model situations were classified from the point of view of their resistance to the applied load.