The chemical compositions and surface structures of two roAp stars with lithium spots (HD 83368 and HD 60435)

The spectra of two roAp stars have been analyzed as part of a project to study lithium in magnetic Ap stars. Variability of the Li I 6708 Å resonance doublet and rare-earth lines was detected, which can be explained using an oblique rotator model with the lithium spots located at the magnetic poles. Synthetic spectra obtained at different rotational phases have yielded the first data on the atmospheric chemical compositions of these spotted stars. Using refined atomic data and the most complete line lists has enabled a detailed study of the spectra near the Li I 6708 Å line and computation of the Li I line profile taking into account the spotted distribution of the lithium over the stellar surfaces. The positions of two lithium spots and lithium abundances for each of the spots have been determined.     

Sustainable landscape management in Slovenia: Environmental improvements for the Velenje coal mining community 1991–2000

The Velenje area (almost 200 km² with over 31,000 inhabitants) is based on the Šalek Valley, which became a leading area of industrialisation and urbanisation after the Second World War, with consequent pollution problems. Various industrial plants polluted the river Paka while more serious hazards arose through the coal mine which is a still causing landscape subsidence and the thermal power station in the neighbourhood of Šoštanj which is a major source of sulphur dioxide and nitrogen oxide pollution. In 1987 there was an ecological protest which marked the beginning of a sustainable development strategy for the community. During the past decade programmes have dealt with the degradation of air, soil and water to achieve cleaner air, a transformation in landuse and enhancement the river's formerly weak self-purifying capabilities. This article examines the changes in the valley since the attention of the authorities was drawn to the deterioration of living conditions. Despite the pressures of transition which have seen unemployment rising to over ten percent, significant environmental improvements have been made and the area stands as a model for the rest of the country. This revised version was published online in July 2006 with corrections to the Cover Date.     

Über die Überlagerungsgeschwindigkeit der Fronten

Summary One can find that over the continent the cold fronts becomes stationary after the sunrise. In the present paper this phenomen is explaned by heating of cold air what causes the increase of the slope of the boundary surface. Because of surface heating of the cold air the horizontal pressure gradient in direction toward the front increases with time, and so increases the transport of the cold air in this direction too. The increasing of the slope of boundary surface that is in connection with the mentioned increased trasport of cold air, causes the convergence of air mass and the ascent of it at the same front (Fig. 2).As the consequence of the heating from the surface and the liberation of latent heat of vaporisation, the volume of cold air increases. In connection with this the divergence of mass occures in the high levels and later one can find at the surface the corresponding fall of pressure. This effects can cause in suitable cases the development of cyclon, similarily as shown on Fig. 4. When the cold air comes from the cold continent over a relatively warm sea surface, the strong heating of cold air occurs and as consequence of this, the cyclogenesis.     

Frequency analysis of geomagnetic beating-type pulsations in thepc3 range

Summary The spectral analysis of samples of beating-type pc3 pulsations, recorded at the Budkov Observatory during the summer months of 1968 and 1969 was carried out in the frequency interval10 mHz100 mHz. The average limits of the pulsation frequency range are roughly20 mHz60 mHz. The centre of the occurrence frequency graphs for both components is at the frequency f_g 41 mHz. The analysis of three separated daily intervals showed a very slight tendency to a systematic decrease in the frequency of the centre from the morning to the afternoon. The study of the sense of rotation of the pulsation disturbance vector in the (X, Y)-plane showed an overall predominancy of L over R-types during daytime, particularly during the morning.     

Electromagnetic induction in a half-space with a cylindrical inhomogeneity

Summary The problem of electromagnetic induction in a half-space with a cylindrical inhomogeneity is treated. Solutions for TE and TM polarization of the exciting electromagnetic field are given, which can be used for computing sounding and profiling curves. The anisotropy of the surface impedance is pointed out, as well as a whole series of other interesting properties of the magnetotelluric field in this model; some of them are also demonstrated on the computed theoretical curves.     

Study of the induction arrow at budkov (Czechoslovakia)

u¶rt;m mam u¶rt;au m ¶rt;a u¶rt;u ma u n aau anu mauaum n amuu ¶rt; a nu¶rt; 1967–1970. aamua ma auum m u¶rt;uu m nu¶rt;a u u am ¶rt;am a¶rt;a m mu ¶rt;¶rt;m -3 amu aua.

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Dedicated to Academician Alois Zátopek on His 65th Birthday     

Way of flying based on compressibility of fluids

Summary The forces due to compressibility of a fluid and their action on moving bodies have been studied. Also a possible practical application of these forces in a propulsion mechanism for vehicles has been discussed.

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Zusammenfassung Im vorliegenden Beitrag wird die Wirkung der Kräfte auf bewegende Körper, die durch Kompressibilität des Mediums bedingt sind, untersucht. Es wird über die Möglichkeit der Konstruktion eines Mechanismus auf diesem Prinzip diskutiert.