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• 1950-1954  (58)
• 1951  (58)
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• 2000-2004
• 1995-1999
• 1950-1954  (58)
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• 1
Electronic Resource
Springer
Pure and applied geophysics 19 (1951), S. 1-18
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Notes: Summary The analysis of surface temperature variations of the moon is based on the equations of heat conduction and heat continuity in the interior of the moon andStefan's law. During a well-defined process, as exemplified by a lunar eclipse, the local heat budget equation establishes a boundary condition at the moon surface which must be satisfied by solutions of the thermal diffusion equation in the interior. Three simplified models of the general case are discussed. They are characterized by special assumptions regarding the depth and time dependency of the thermic qualities of the material underlying the moon's surface. In short, the thermal diffusivity is assumed to be constant in the first model, a linear depth function in the second and a time function in the third. A unique solution can be obtained for model No. I such that the absolute surface temperature is approximately inversely proportional to the 6th root of time during the phase of total eclipse.Epstein's conclusion that the average surface of the moon might consist of highly porous rocks or fine dust is confirmed by the order of magnitude of the heat conductivity which produces the best fit between the theoretical curves and a plot ofPettit's observational data during the lunar eclipse of 1939. Existing differences between the observed and theoretical curves during the totality phase of the eclipse can be reduced by the employment of the second model. A crude estimate shows that the average dust cover resting on more solid ground of lunar rocks might possibly have a thickness of approximately 0.5 meters.
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• 2
Electronic Resource
Springer
Pure and applied geophysics 19 (1951), S. 19-32
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Description / Table of Contents: Summary A short review of observations concerning the earth-current (E.C.), as carried out in Germany up to this day, is followed by a description of the corresponding installation set up in the Magnetic Observatory at Fürstenfeldbruck. The subsequent components of E.C. are recorded on colour-point-recorders: Magnetic East-West (distance of electrodes 176 yards), geographic E-W (165 yards) and geogr. South-North (165 yards). The Horizontal-Intensity is simultaneously recorded upon one of the two instruments by the use of differential-photoelements.—A remarkable point is the fact that the magnetic variations inH andD and the fluctuations of the perpendicular components of E.C. are congruent in the course of which different phases may be observed. The curves of the first derivation of the magnetic components coincide with those of the corresponding E.C.-components in its maximis and minimis whereby the magnetically produced part of said E.C. is proved to be the actual cause of induction. Another very striking fact is the difference of the amplitudes of the EW- and SN-Components in above mentioned E.C. showing a relation of 6∶1.—In applying the formulas of electric transformators to the currentsystems within the ionosphere and the earth one is likely to find a plausible explanation of those effects. To this very purpose the evident vector-diagrams for voltage-current in this earth physical phenomen are used.
Notes: Zusammenfassung Nach kurzer Betrachtung der seither in Deutschland durchgeführten Erdstrombeobachtungen wird die Anlage am Observatorium in Fürstenfeldbruck beschrieben. Folgende Erdstromkomponenten werden auf empfindlichen Farben-Punktschrieben. (Firma H & B) registriert: Magnetisch Ost-West (Elektrodenabstand 160 m), geographisch Ost-West (150 m) und geogr. Süd-Nord (150m). Gleichzeitig wird die Horizontalintensität über eine Differential-Photozelle auf einem der beiden Geräte mitgeschrieben.—Bemerkenswert ist die Uebereinstimmung der erdmagnetischen Variationen inH undD mit den Schwankungen der senkrecht dazu liegenden Erdstromkomponenten, wobei verschiedene Phasen zu beobachten sind. Die Kurven der ersten zeitlichen Ableitung der magnetischen Komponenten koinzidieren mit denen der entsprechenden Erdstromkomponenten in den Maximis und Minimis, was ein Beweis für die Induktionsursache des magnetisch bedingten Teils des Erdstroms ist. Auffallend ist der Unterschied der Amplituden der Ost-West- und Süd-Nord-Komponenten im Erdstrom (ES), die sich wie 6∶1 verhalten.—Die Beobachtungen über grosse Elektrodenentfernungen haben bei verschieden langen Variationsperioden in der Deutung zu Irrtümern Anlass gegeben. Durch Anwendung der Formeln der elektrischen Transformatoren auf die Stromsysteme in der Ionosphäre und in der Erde kann eine plausible Erklärung der Effekte gefunden werden. Zu diesem Zweck werden die anschaulichen Spannungs-Strom-Diagramme in Vektordarstellung für diese erdphysikalischen Erscheinungen angewandt.
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• 3
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Springer
Pure and applied geophysics 20 (1951), S. 24-26
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Description / Table of Contents: Résumé On rencontre souvent des problèmes où divers oscillateurs dé périodes propres différentesT 0j et de même coefficient d'amortissement ε, sont attaqués par un phénomène sinusoïdal de périodeT. Les courbes classiques qui donnent l'amplitude et la phase du mouvement forcé en fonction du rapportT/T 0 pour différentes valeurs du paramètreh=εT 0/2π, ne peuvent alors être utilisées. Nous donnons ici les courbes correspondant à des valeurs différentes du paramètreh(=ε/n)=ε T/2π.
Notes: Summary Frequency characteristics of a linear oscillator or a seismometer, whose equation of free oscillation is $$\ddot x + 2\varepsilon \dot x$$ +n 2 x=0, are usually represented by takingh(=ε/n) as parameters. In this case, however, the independent variable is the frequency of impressed force or displacement from outside on the oscillator. But, we often encounter those cases, where the frequencies from outside are constant, and the frequency of the oscillator or pick-up is to be changed, or the several oscillators with various frequencies are to be used. Then, of course,h cannot be taken as parameters, as they vary with the oscillator's frequencyn. The author here calculated the amplitude- and phase-characteristics for the latter case, taking $$\bar h$$ (=ε/n) as parameters and represented them in thick lines in the figures together with the ordinary ones in thin lines.
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• 4
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Springer
Pure and applied geophysics 20 (1951), S. 1-14
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Description / Table of Contents: Summary In the past, spectral analysis of oscillations was based upon the Fourier transform almost exclusively. This spectral decomposition is shown to be merely a special case of a more general type of decomposition which is based upon the concept of exhaustion largely used in periodographic analysis. The exhaustion principle is extended to continuous variable shift periods, the result being an integral transform similar to the Fourier transform, with the exception that the cosine function is replaced by a series of equidistantDirac functions. A periodograph is described which permits continuous exhaustion analysis of oscillogram patterns by means of an optical projection device.
Notes: Zusammenfassung Die Spektralanalyse von Schwingungsvorgängen basierte bisher ausschliesslich auf der Fourierschen Funktionaltransformation. Es wird gezeigt, dass diese Art der spektralen Zerlegung nur ein Sonderfall einer allgemeinen Zerlegungsart ist, die auf dem in der periodographischen Analyse vielbenutzten Exhaustionsprinzip beruht. Dieses Prinzip wird auf kontinuierlich variable Verschiebungsweiten ausgedehnt und führt dann zu einer Integraltransformation, die der Fourier-Transformation analog gebildet ist, aber an Stelle der Cosinusfunktion eine Summe von gleichabständigenDirac-Funktionen enthält. Es wird ein Periodograph beschrieben, der eine kontinuierliche Exhaustionsanalyse von Oszillogrammschablonen nach dem optischen Projektionsverfahren ermöglicht.
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• 5
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Springer
Pure and applied geophysics 20 (1951), S. 27-30
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Notes: Summary Following on the examination of the frequencies of S. Cs. and S. Is. given in a recent paper (1), the diurnal variation of theH-amplitudes at the six stations Cheltenham, Tucson, San Juan, Honolulu, Huancayo and Watheroo during the period 1926–46 is investigated, and in this S. Cs. and S. Is. do not appear to differ greatly in their behaviour. Except in the case of Huancayo, the greatest amplitudes occur near 0h. local time, after which there is a fall to the lowest values about 7h. The S. Is. amplitudes may have a secondary minimum near 18h., but this is not certain.
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• 6
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Springer
Pure and applied geophysics 20 (1951), S. 50-55
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Notes: Summary Tangential and normal equations of horizontal motion along and normal to the characteristic lines (for example: stream lines, isobars, isotherms, etc.) are derived in general form. Then the later section of this paper is devoted to applications to natural coordinates and the coordinates chosen to lie parallel and normal to the isobars.
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• 7
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Springer
Pure and applied geophysics 20 (1951), S. 62-66
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Description / Table of Contents: Summary From a drawing one finds the size and dip of a screen to protect a pyranometer against the sun.
Notes: Zusammenfassung Aus einer einfachen Zeichnung ergibt sich die Grösse und optimale Neigung eines Schirmes zum Abblenden der Sonne von einem Pyranometer.
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• 8
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Springer
Pure and applied geophysics 20 (1951), S. 56-61
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Notes: Summary Many writers treated on the problem of dynamic instability of westerly flow due to the excessive horizontal shear, and the present author discusses the corresponding dynamic instability due to the vertical shear. The critical vertical shear in indifferent stratification is given by the condition — the meridional component of absolute vorticity vanishes, — and is an approximate negative valueof 10−4 sec −1 in middle latitude. However the critical vertical shear in normal stable stratification is a fairly large negative value of 2 sec−1. It might be emphasized that the problem of this study differs fromRichardson's criterion of turbulence, for the present author discusses the condition under which the zonal flow is dynamically stable, whileRichardson expressed the condition under which the turbulence will decrease.
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• 9
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Springer
Pure and applied geophysics 20 (1951), S. 31-45
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
Description / Table of Contents: Zusammenfassung Wenn man die magnetische Vertikalintensität in einem Gebiet kennt, ist es unter gewissen Bedingungen, die oft erfüllt sind, möglich in willkürlich gewählten Punkten des Gebietes — mit Ausnahme des Randgebietes — die Abweichungen ΔH und ΔD der HorizontalintensitätH und der DeklinationD von konstanten Werten zu berechnen. Weiter unten sind Einzelheiten der praktischen Ausführung anhand eines Beispiels mitgeteilt. Die mathematische Grundlage der Berechnungen ist in der Einleitung skizziert; doch können die folgenden Abschnitte auch unabhängig von ihn verstanden werden. Für die Berechnungen wurde ein, Integrationsgitter (Abb. 1) verwendet, und die Methode selber ist unter «2. Procedure» beschrieben. In Abb. 2 und 3 zeigen die Zahlen bei den Kreuze die in dieser Weise berechneten Werte vonH undD, angegeben in Gammawerten und Bogenminuten; (die isomagnetischen Linien in Abb. 2 sind auf Grund vonbeobachteten H-Werten gezeichnet worden; in Abb. 3 sind die beobachtetenD-Werte in kleiner Typen gedruckt). In den Abschnitten 3 und 4 werden die Genauigkeit und die Anwendungsmöglichkeiten der Methode diskutiert.
Notes: Abstract If the magnetic vertical intensityZ is known over a certain area, it is possible, under more precisely defined conditions which are often complied with, at arbitrary points of the same area—though with the exception of the marginal area—to calculate the deviations of the horizontal intensityH and the magnetic declinationD, ΔH and ΔD, from constant values. Below some details of the calculation in practice are given, i. a. by means of an example, the mathematic basis for the calculations being outlined in the introduction (the succeeding text may, however, be read independently thereof). A graticule, as seen in Fig. 1, was used in the calculations, and the method itself is described under «2. Procedure». In Figs. 2 and 3, the figures at the crosses denote the values ofH andD computed in this way, indicated in gammas and arc-minutes, respectively; (the isomagneticH-lines in Fig. 2 are drawn on the basis ofobserved H-values; in Fig. 3 the observedD0values themselves are given in figures in small type). The accuracy of and the possibilities for application of the method are discussed in the later sections.
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• 10
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Springer
Pure and applied geophysics 20 (1951), S. 85-85
ISSN: 1420-9136
Source: Springer Online Journal Archives 1860-2000
Topics: Geosciences , Physics
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