On the propagation of wave from a cylindrical cavity

Summary This paper discusses the disturbance produced in an infinite layer of non-homogeneous elastic material characterised by =0 ⁿ and =0ⁿ(n>0) where and are the density and shear modulus respectively of the material, due to periodic torsional force applied on the wall of a cylindrical hole in the layer. The variation of the displacement component with the radius vector is shown graphically and compared with the corresponding homogeneous case.     

Waves in an elastic plate with an irregular boundary

Summary Green's function corresponding to the displacements for anSH-line source inside a wedge shaped medium finite or infinite in which the density and the elastic parameter are not constant throughout but some class of function ofr, the radial distance (i.e. and satisfy some differential equation) has been obtained. The paths of propagation of the cylindrical waves, their reflections on different boundaries and their continuous refractions within the medium has been clearly established. The scattered field from the different parts of the body have been pointed out with prescribed distribution of and in this inhomogeneous wedge. It is shown that for some distribution of and the rays are curved and the reflections at the two plane boundaries occur in such a way that no ray will go to infinity by reflection, rather they are coming back towards the apex after suitable number of reflections with variable intensity. Also there are some distributions of and in the same class as mentioned earlier, such that the behaviour of the waves is similar to that in a homogeneous wedge, i.e. these waves will go to infinity by a suitable number of reflections and ultimately die out. The first case is quite unlike the usual homogeneous medium with non parallel boundaries and so care must be taken in computing the field within the nonhomogeneous medium within the non-parallel boundaries.     

On the possibility of utilizing grid reports in a local model of short-range forecast of meteorological elements

Summary In the experiment described, we test the possibility of utilizing forecasts of the pressure field, contained in GRID reports, to solve the problem of horizontal boundary conditions of a local model of short-range forecast of meteorological elements. We prove that the assumption of a linear tendency of the prognostic variables in the boundary region yields good results, using the Perkey-Kreitzberg method[1], even if applied to period T=24 hrs. In the Perkey-Kreitzberg method the effect of the horizontal diffusion in the boundary region is suppressed[2]. However, considering the diffusive term apart from the procedure of the method mentioned proves detrimental to the forecast.

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nua num n m unau n n ¶rt;au, ¶rt;au ¶rt; ¶rt; u numaau u a ¶rt;u am na muu m. aam, m n¶rt;nu u m¶rt;uu nmuu n au amu nu unauu m¶rt;a u- [1] ¶rt;am u mam ¶rt;a nu nuuu nu¶rt; T=24 a. m¶rt; u- nu¶rt;um n¶rt;au uuuma ¶rt;uuu au amu[2]. ama ¶rt;u a n¶rt; nu¶rt; m¶rt;a nu¶rt;um, ¶rt;a, ¶rt;u n.

     

Precipitation of electrons after geomagnetic substorms

Summary Precipitating electrons E_e>10 keV and E_e>30 keV and protons E_p=150 to 300 keV are analyzed using data obtained from the low-altitude polar-orbiting satellite Interkozmos-17 after the magnetic storm of December 2, 1977. On December 3, an isolated substrom occurred, and strong electron precipitation was observed in the midnigt sector, while the sequence of substorms of December 5 expanded its longitudinal extent from 22 MLT through the morning to 12 MLT. The different character of the precipitation, in the two cases mentioned, is discussed in relation to the changes of conditions for the generation of cyclotron instability as well as to the effect of particle injection. Proton precipitation occurred only in the night sector, most probably just inside the plasmapause.

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¶rt; aau nau m E_e>10 u E_e>30 u nm E_p=150–300 n uu n uuma nmua n um m-17 n aum u 2. ¶rt;a 1977. 3. 12. nua uuaa u u nau m aumua m mo u. a n¶rt;amm 5. 12. nua auu ¶rt;m umaa, m m nau, a u m 22 MLT mu m ¶rt; 12 MLT. a aam nau nu¶rt; ¶rt; a ¶rt;am aa uu u ¶rt; uu um mumu u ¶rt;mu uuu amu. nau nm n¶rt;u m m u m a naana mu naa.

     

The parallactic refraction determined with the aid of meteorological balloon data

¶rt; u n ¶rt; (nmu) muauu m m naaamu auu . am mu uu nu unauu ¶rt;a mu ¶rt; nuu u umuau. am ¶rt; ¶rt;u ¶rt;uua u nuam n uu. ¶rt;m uau u au nm u mnum ¶rt;a. a mm n¶rt;a ±0,1 naaamu auu ¶rt; um amu ¶rt; z=80° u ¶rt; m u ¶rt; =10 (uuaa). u¶rt;um nm u au am[2].     

Radioactive and trace element distribution in basaltic rocks of Lower Silesia

Summary The distribution of radioactive(Th, U, K) and selected trace(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) elements in volcanic rocks from the Opole and Jawor regions of the Lower Silesia has been studied. The behaviour of these elements in the studied rocks indicates that the Lower Silesian volcanic rocks are characterized by less differentiated type than other volcanic rocks of the Bohemian Massif, the Opole rock types probably having a less differentiated character than the Jawor rock types.

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¶rt;a an¶rt;u a¶rt;uamu(Th, U, K) u m ¶rt;u(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) m auu n¶rt;a am n u u uuu. a n mam n¶rt;num, m aum u uuu n¶rt;mam ¶rt; aamuu n¶rt; u ¶rt;uuau, aum u ana¶rt; uu. au a n¶rt;num, m auu n¶rt; amu n ¶rt;uuau ma ua n¶rt; u amu .

     

Über das Flimmern und Schweben des Zielbildes

Zusammenfassung In zwei Beobachtungsserien von 24 Stunden ist jede zweite Stunde die Schwankung des Zielbildes beobachtet und gleichzeitig die Temperaturdifferenz zwischen den Höhen 0.5 und 2.5 m gemessen worden. Aus diesen Beobachtungen gehen folgende Resultate hervor. Kurz nach Sonnenaufgang ist das Zielbild unbeweglich. Bald beginnt es zu flimmern, zuerst schwach und langsam (einmal in der Sek.) später stärker und schneller (5 mal in der Sek.). Das Flimmern erreicht sein Maximum etwas nach Mittag, vermindert sich dann und wird Null kurz vor Sonnenuntergang. Von hier an beginnt das Zielbild sehr langsam (in Perioden von Minuten) zu schweben. Der Betrag des Flimmerns ist proportional der 1.68-Potenz der Zielweite. Sie hängt von dem Temperaturgradienten ab, und z. B. bei der Zielweite 75 m beträgtF ₇₅=0.66–1.42 mm, wo die Temperaturdifferenz zwischen den Höhen 0.5 und 2.5 m bezeichnet. Der Betrag des Schwebens ist proportional der 2.05-Potenz der Zielweite. Sie hängt von dem Temperaturgradienten ab, und z. B. bei der Zielweite 125 m beträgtS ₁₂₅=1.3+4.02 mm, wo die obenangegebene Bedeutung hat. Zwischen dem ZielungsfehlerZ und dem FlimmernF besteht die BeziehungZ=0.11++0.029F mm. Das Schweben wirkt sehr stark auf die Zielungsgenauigkeit ein, obgleich beim Vorkommen des Schwebens das Zielbild nach dem Augenmass unbeweglich erscheint.

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Summary The oscillation of the sight point picture in telescope and simultaneously the difference of the air temperatures between the hights of 0.5 and 2.5 meters have been observed every two hours through two clear days and nights. Hereby the following results have been obtained. Short after the sunrise the sight point picture is quite immovable. Soon after it beginns to vibrate, at first slightly and slowly (one time in second) and then more violently and quickly (five times in second). The vibration attains its maximum short after the noon, then it decreases and becomes zero not long before the sunset. From now till the sunrise the sight point picture is swaying very slowly (in periods of several minutes). The vibration is proportional to the 1.68-power of the sight length. It correlates the vertical temperature gradient, and the vibration is e. g. for the sight of 75 m:F ₇₅=0.66–1.42 mm, where means the temperature increase from 0.5 to 2.5 m (here negative). The swaying is proportional to the 2.05-power of the sight length. It correlates the gradient, and the swaying is e. g. for the sight of 125 m:S ₁₂₅=1.3+4.02 mm, where has the same meaning as above. Between the sight errorZ and the vibrationF a relation:Z=0.11+0.029F mm is to be seen. Thus the accuracy of the sighting is not very sensitive to the vibration.

     

Determination of tidal torques independently of densities

Summary The components of the tidal torques along the axes of the inertia ellipsoid of a perfectly elastic Earth have been derived quite independently of the density distribution of masses within the Earth. It has been demonstrated that not only the sectorial, but also the tesseral terms in the tidal forming potential are responsible for the tidal deceleration of the Earth's rotation.

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am ¶rt; mau ma nuu u m u a um unu¶rt;a uuu u¶rt;a n u, auu m ¶rt;a an¶rt;uu nmm a. aa, m nuu a¶rt;u au u a m muau, u mau nuuu au nuua nmua.

     

Numerical modelling of time-harmonic seismic wave fields in simple structures by the gaussian beam method. part I

m¶rt;au n unm ¶rt; u ¶rt;uau uu n m nm ¶rt; ¶rt;. a uau ¶rt;m a ma m nau a¶rt;a, amu aa mu. au mu uu naam, m m¶rt;au n ¶rt;am ¶rt;mam m mam ¶rt;a u amu aa mu (. u. 9). aumu amu, uauau n ma nam ¶rt;a . ¶rt; amu m am ¶rt;m ¶rt;am mumm mam a naama am, an. aa uuau n, naama uauau n, um¶rt;.     

Tidal contribution of the satellites to removing the angular momentum of Jupiter

Summary It has been shown that dynamically, on the basis of the distribution of angular momenta, the Jovian system cannot be considered an analogue within the Solar system. The total tidal decrease in the angular momentum of Jupiter and in its angular velocity of rotation have been estimated, as well as the loss of mechanical energy due to tidal dissipation. It has been concluded that there are no dynamical contradictions with the hypothesis of the common cosmogonic origin of Jupiter and of its eight close satellites.

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aam, m ¶rt;uauu, n an¶rt;u m uma ¶rt;uu, um numa umam aayu um. a a y au ma uma ¶rt;uu numa u z mu z au u—a nuuz mu, ma a nmu au yuu um u—a ¶rt;uunauu. a au, m m ¶rt;uauu azau zunm m zuu aaa numa u z uau u nmu.

     

Stratospheric ozone variability near the IMF sector boundary

Summary We search for the effects of the interplanetary magnetic field (IMF) sector boundary crossing (SBC) in upper stratospheric ozone. The SBUV data (Nimbus-7) at the 10, 3 and 1 hPa levels are analysed for latitudes 45° N and 55° N for winters of the period December 1979 to December 1982. An effect of the IMF SBC wos only found at the 10 hPa level. These first results concerning the IMF SBC effect in upper stratospheric ozone are rather preliminary.

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¶rt;m uu nu mau () nam aum n () a mam. SBUV ¶rt;a (u-7) a nm ¶rt;au 10, 3 u 1a aauum ¶rt; um 45° u 55° . . ua nu¶rt;a ¶rt;a 1979 – ¶rt;a 1982. m uu a¶rt; m a 10a. mu n mam n uuu a mam m n¶rt;aumu.

     

An effective method of frequency analyses of time series of geo-physical quantities

a u uma naau ¶rt; m¶rt; ¶rt; aaua ¶rt;auu uu. naau ¶rt; naam , ¶rt;mu mau a, m aa naau ¶rt;am n a au aauu uu auumu m amu m aaa um ¶rt;uam. m¶rt; m ¶rt;mam mu ¶rt;a nu auu u m mu, ma m nuu ma a a .     

On the spiral structure of atmospheric vortices

a au au a ¶rt;am m ¶rt;uauu n¶rt;nu mau nua am u nu uu, m n amu n nua n uau mua mu.     

Predictions of magnetic fields for Uranus and Neptune

Summary The magnetic moments of Uranus and Neptune have been predicted using different scaling laws of planetary magnetism. The predictions for Uranus cover a broad band of values from very weak magnetic fields (tidal relations) to moderate fields (thermal convection hypothesis). Therefore, the direct measurements of this field by Voyager 2 (January 1986) will be very important for testing the individual hapotheses.

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a m ama a ¶rt; amua nam ¶rt;a n aum m nam a a nm. aa n¶rt;nmu nuu mu, ¶rt;m u¶rt;am a aum n a nmu aa u u a nmu nma.

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Presented at the Fifth Scientific Assembly of IAGA in Prague 1985.     

Changes in the reflectivity of the midlatitude ionosphere with respect to the ULF (Pc1) signal

Summary The method of numerical modelling of ionospheric filtration of the Fourier components of a signal from the frequency range of Pc1 micropulsations is employed in the spectral analysis (frequency f, angle of incidence ) of the relative characteristic of the amplitude and energy reflectivity of the ionospheric layer with respect to ordinary Alfvén modes incident in the meridional plane. The results are presented for four different models characterizing the midlatitude day- and night-time ionosphere under low and high solar activity. The results indicate the specificity of filtration of ordinary Alfvén waves. It is proved that the lower region of the modelled ionosphere, as part of the midlatitude ionospheric wave guide (in particular the F2 layer), behaves like an Alfvén resonator in the given spectral range.

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m¶rt; u ¶rt;uau u umauu -mau uaa u amm ¶rt;uanaa unau 1 n¶rtum nma aau (amma f, a¶rt;u ) mum anum¶rt; u mu maamu u ¶rt; ¶rt; a, a¶rt;au a u u¶rt;ua nmu. mam n¶rt;aam ¶rt; m a ¶rt; ¶rt;um m ¶rt; u u nu u u nu amumu. aam nuum umauu a. naa, m ua am ¶rt;ua u (a am F2-u ¶rt;um ¶rt;a) ¶rt;m nma ¶rt;uana a am a.

     

Is there any relation between the sun's motion and global seismic activity?

Summary The seismic energy released by global earthquake activity with time was correlated with F=||, where || is the absolute value of the change of the Sun's acceleration with time. For deep earthquakes and probability P=0.95, the coefficient of correlation was found to be around 0.4. For shallow earthquakes, the dependence was not proved.

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¶rt;a u uu (1900–1982.) ua ¶rt; F=||,¶rt; || am au uu u a. mu (h>60 ) u ¶rt; mmu =0.95 uum uu ¶rt;muam0.45. nm mu auum a n¶rt;m¶rt;a.

     

Calculation of particle distribution by the data on spectral transparency

, , . . , , , . , , .Summary A general method for obtain the particle size distribution curve of the dispersed system is developed according to data of its spectral transparency, based onMellin's transformation. The method does not contain any arbitrary suppositions about spectrum character of particles. A simple calculation scheme is supposed, examples of inversion are given, the range of spectrum and the accuracy of transparency measurements necessary to obtain the inversion with a given accuracy are estimated. The calculation scheme is appropriate for every kind of errors of measurement and calculation and contains moderate requirements to their accuracy.     

Travel times of Friuli earthquakes propagating to the Bohemian Massif

17 mmu u uma uu 1976. anua 5 ¶rt;numu mauumu u¶rt;a mu u m na Pn, Pg, Sn u Sg. u¶rt; numm muam u mum ma¶rt;am¶rt;a ¶rt; uu mmu n¶rt;naam nu m m uamm aumm. ¶rt;am nu m mmu maua.     

Expansion of a function given over an equipotential surface into spherical harmonics

¶rt;m ¶rt; uuauu uum auu uu, a¶rt;a a nmunmuaa, ¶rt; n uu u. aa, m u u ¶rt;um nmu, uu n¶rt; m nm, u aaaa u aa m nmua.     

Topographic effects on tidal strains and tilts

Summary Topographic effects on tidal strains and tilts are studied using a homogeneous elastic spherical model. Expressions for local perturbing strains and tilts are derive das functions of the physical and geometrical parameters of the model. It is demonstrated that tidal tilts are affected more by the topography than tidal strains.

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n ¶rt;¶rt; n u ¶rt;u u¶rt;a uu a mmu a nuu ¶rt;auu u a. ¶rt; au, nuau a uau nuu ¶rt;au u a auumu m uuu umuu naam ¶rt;u. aa, m uau nuu a uau nuu ¶rt;au.