bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Reynolds stresses in mean‐field hydrodynamics II. Two‐dimensional turbulence and the problem of negative viscosity
Authors: Krause F. , Rüdiger G. 
Published: July 2007

AbstractThe methods proposed in a foregoing paper are used for the derivation of the eddy viscosity of a two‐dimensional homogeneous isotropic turbulence. In contrast to three‐dimensional isotropic turbulence is shown that for the two‐dimensional case the eddy viscosity (i) has no definite sign, (ii) tends to zero if the molecular viscosity tends to zero, (iii) is negative for special cases. However, the modes with large wave numbers decay in any case as is shown by investigating a dispersion relation.
Gravitational attenuation and the internal heating of planetary bodies
Authors: Crowley R. J. , Woodward J. F. , Yourgrau W. 
Published: July 2007

AbstractThe hypothesis of gravitational attenuation is discussed and several theoretical problems with possible solutions are noted. It is pointed out that, if energy were attenuated out of the gravitational field by matter, it would ultimately be thermalized. Geothermal data are then employed to establish an upper limit to the gravitational attenuation coefficient, some fifteen orders of magnitude smaller than the currently accepted value. The internal heating of other planetary bodies is investigated to see if a yet smaller upper limit is deducible therefrom – with negative results.
Lichtelektrische Untersuchung der drei Mangan‐Sterne HD 207 857, HD 220 933 und HD 225 289
Authors: Hildebrandt G. , Schöneich W. 
Published: July 2007

AbstractDie lichtelektrischen Untersuchungen in den Jahren 1969 und 1970 der drei Mangan‐Sterne HD 207857, HD 220933 und HD 225289 im UBV‐System zeigen für alle drei Objekte einen periodischen Lichtwechsel mit einer Amplitude von etwa 0.01 mag. Die Lichtkurve für HD 207857 zeigt eine Doppelwelle bei einer Periode von 20.70 Tagen. Die Periode für HD 220933 ergab sich zu 6.97 Tagen und für HD 225289 zu 6.4332 Tagen.
Non,thermal Cosmic Gravitational Radiation and Redshift Fluctuations
Authors: Dautcourt G. 
Published: July 2007

AbstractIntergalactic gravitational radiation fields with wavelengths in the range of 1 to 103 Megaparsecs have remarkable observational effects if the energy density of the fields becomes comparable to the equivalent “critical” cosmological matter density χo = 3H02. In this case the perturbation in the space‐time metric caused by the radiation field is high enough to change the frequency and to shift the path of light rays of extragalactic objects in a random manner by observable amounts.The present paper discusses the wave spectrum as a function of cosmic time and gives a statistical treatment of the redshift fluctuations.
On the Influence of a Large‐scale Magnetic Field on Turbulent Motions in an Electrically Conducting Medium
Authors: Rädler K.‐H. 
Published: July 2007

AbstractThis paper deals with turbulent motions in a homogeneous incompressible electrically conducting medium in the presence of a magnetic field which is on average homogeneous and stationary. Using a model in which the turbulence is produced by a stochastic body force, and supposing a weak interaction between motion and magnetic field, a method is developed for calculating the pair correlation tensor of the velocity field from that occuring in a zero magnetic field. As an example, the pair‐correlation tensor for a homogeneous stationary turbulence, which is isotropic and mirror‐symmetric for zero magnetic field, is determined. With obvious assumptions on the correlation for zero field, two results are obtained. Firstly, the turbulent velocity is reduced by the magnetic field, the component parallel to the field, however, less than those perpendicular to it. Secondly, the correlation length parallel to the field turns out to be greater than the one perpendicular to it, indicating a tendency towards two‐dimensional motion. Finally, the possibility of special situations is briefly discussed in which the turbulent velocity is enhanced by the magnetic field, and the anisotropies of the velocity components and the correlation lengths are opposite to those above.
Die träge und die schwere Masse eines Himmelskörpers nach der trägheitsfreien Dynamik und die Selbstabsorption der Schwerkraft
Authors: Treder H.‐J. 
Published: July 2007

AbstractIn unserer “trägheitsfreien” Dynamik (TREDER 1972) sind die effektiven trä,en Massen \documentclass{article}\pagestyle{empty}\begin{document}$ m_\alpha ^*$\end{document} der Teilchen Kα homogene Funktionen des “äußeren” NEWTONschen Gravitationspotentials \documentclass{article}\pagestyle{empty}\begin{document}$ f\sum\limits_\beta {'\frac{{m\beta }}{{\gamma _{\alpha \beta } }}}. $\end{document} Wir zeigen, daß aus dieser “Trägheitsinduktion” resultiert, daß die Summe \documentclass{article}\pagestyle{empty}\begin{document}$ \sum\limits_A^N {m_A^* } $\end{document} der effektiven trägen Massen \documentclass{article}\pagestyle{empty}\begin{document}$ m_A^* $\end{document} der N Teilchen KA eines Sterns immer größer ist als seine Gesamtmasse M*

hierbei ist M* die dynamisch bestimmte träge Masse des Sterns. Als Folge hiervon sind die tatsächlichen Gravitations‐Beschleunigungen der Teilchen KA im Sterninnern immer kleiner als diejenigen, die sich NEWTONisch aus der gravischen Masse \documentclass{article}\pagestyle{empty}\begin{document}$ fM = f\sum {m_A } $\end{document} des Sterns berechnen würden. — Wir vergleichen diesen Effekt mit dem der “Selbstabsorption der Schwere”, wie er aus unserer Tetradenfeldtheorie der Gravitation (TREDER 1967/71) folgt.
The General Metrical Fundamental Form of the DE SITTER Universes
Authors: Treder H.‐J. 
Published: July 2007

AbstractDas allgemeine Linienelement eines DE SITTER‐Kosmos mit

hängt von zwei Integrationskonstanten A und B ab. Mit EINSTEIN's kosmologischer Konstante \documentclass{article}\pagestyle{empty}\begin{document}$ \lambda > o $\end{document} ist

und \documentclass{article}\pagestyle{empty}\begin{document}$ \varepsilon {\rm = }\frac{{{\rm 4}\lambda }}{{\rm 3}}AB $\end{document} AB gemäß der FRIEDMANNschen Gleichung.
Die Wechselwirkung zwischen homogener Turbulenz und inhomogenem magnetischen Feld in der Umgebung neutraler Flächen
Authors: RÜDIGER G. 
Published: July 2007

AbstractIn Fortführung der Untersuchung über den Einfluß eines konstanten Magnetfeldes auf homogene Turbulenz (RÜDIGER 1974) wird im Vorliegenden die Wirkung eines schwachen, schwach räumlich veränderlichen, eine Nullfläche enthaltenden Magnetfeldes bestimmt. Es wird nunmehr nicht nur die Isotropie sondern auch die Homogenität des ursprünglich als homogen und isotrop eingeführten Turbulenzfeldes aufgehoben. Wegen der endlichen Korrelationslänge wird das Bewegungsverhalten auch innerhalb der neutralen Schicht beeinflußt. Die dort anzutreffende anisotrope Dämpfung der turbulenten Bewegung wird für eine spezielle Klasse von Spektralfunktionen zwei‐ und dreidimensionaler Turbulenz angegeben.Fernet wird der Einfluß des nunmehr inhomogenen Turbulenzfeldes auf das die Inhomogenität hervorrufende mittlere Magnetfeld bestimmt. Man erhält eine zeitliche Veränderung des mittleren Magnetfeldes, die mit Hilfe des BOCHNERschen Theorems als zusätzlicher Zerfallsmechanismus charakterisierbar ist.
Structural Investigations in the Central Part of the Coma Cluster on the Base of Equidensity Diagrams. I.
Authors: Richter N. , HÖGNER W. 
Published: July 2007

AbstractAuf der Grundlage einer photographischen Himmelsaufnahme im Farbsystem V, die mit der Schmidtkamera 134/200/400 cm des Karl‐Schwarzschild‐Observatoriums Tautenburg erhalten wurde, werden mit Hilfe photographischer Äquidensiten maximale Durchmesser von Galaxien im Zentrum des Coma‐Haufens abgeleitet. Ein weiteres System von Durchmesserwerten bezieht sich auf mittlere Schwärzungsgebiete der Objekte. Die Ergebnisse werden mit einer Statistik von ROOD und BAUM verglichen, deren Durchmesserbestimmungen durch visuelle Messungen auf Platten erhalten wurden, die mit dem 5‐Meter‐Spiegel der Hale Observatories gewonnen wurden. Beide Statistiken erreichen Galaxien bis 19m. Sie sind vollständig bis 17m.5. Es zeigt sich, daß die Tautenburger Durchmesser die von ROOD und BAUM im Mittel um das Dreifache übertreffen, in zahlreichen Fällen um das Fünffache. Es werden Durchmesser‐Helligkeits‐Diagramme abgeleitet, Elliptizitäten der Objekte bestimmt und Korrektionswerte zur photometrischen Entzerrung von stark geneigten Objekten abgeleitet. Zur Beschreibung der Haufenstruktur werden Durchmesserfunktionen anstelle von Helligkeitsfunktionen abgeleitet. Die Genauigkeit der mit der Äquidensitenmethode aus den Durchmesser‐Helligkeits‐Diagrammen dargestellten Einzelhelligkeiten übertrifft die analogen Werte von ROOD und BAUM um das Doppelte.
Astrophysikalische Diskussion des COMPTONeffektes im äußeren Magnetfeld
Authors: Herrmann J. , KÄMpfer B. 
Published: July 2007

AbstractDer Einfluß eines äußeren, zeitlich konstanten und homogenen Magnetfeldes auf das COMPTONspektrum, das durch die Streuung einer Photonenverteilung an einer Verteilung ultrarelativistischer Elektronen entsteht, wird diskutiert.
On the mass discrepancy in double galaxies
Authors: Oleak H. 
Published: July 2007

AbstractComparing the M/L‐distribution function of single spiral and irregular galaxies with that of double galaxies (S,S and E,E) from the list of KARACHENTSEV (1974) it can be shown that the mass discrepancy can be ascribed to the skewedness of this frequency function and thus to the strong dependence of the mean value of M/L on the dispersion. An unavoidable enlargement of the dispersion by errors of measurement and wrong attachment of objects of the sample always raises the mean of M/L. This effect could be then mistaken for a mass discrepancy.
Counts of galaxies in the region of the “intergalactic dark cloud” near ι microscopii
Authors: Meinunger I. 
Published: July 2007

AbstractThe distribution of the total numbers of galaxies down to about 18TH magnitude on 84 squares is largely in agreement with the structure of the hypothetic intergalactic absorbing cloud near ι Microscopii found by C. HOFFMEISTER. The counts of galaxies were performed on the WHITEOAK prints covering that region.
Lichtelektrische Untersuchungen des Ap‐Sterns HD 148112
Authors: Schöneich W. , Hildebrandt G. 
Published: July 2007

AbstractDer Ap‐Stern HD 148112 wurde im Zeitraum von Juli 1971 bis Juli 1972 lichtelektrisch im BV‐System untersucht. Der Stern zeigt mit einer Periode von 2.951 Tagen eine Doppelwelle in der Lichtkurve. Die Amplituden betragen in beiden Farbbereichen etwa 0.04 mag.
BOLTZMANNS Kosmogonie und die hierarchische Struktur des Kosmos
Authors: Treder H.‐J. 
Published: July 2007

AbstractGemäß BOLTZMANNS Kosmogonie quasi‐isolierter Systeme ist die Manningfaltigkeit der möglichen (d. i. mit den kanonischen Bewegungsgleichungen und den als „Hemmungen”︁ wirkenden Nebenbedingungen verträglichen) Vorgeschichten ein Maß für die Wahrscheinlichkeit des gegenwärtigen Zustandes eines Systems Σ. Diese Fundamental‐Hypothese von BOLTZMANN ist die Aufklärung des sogenannten „Wiederkehreinwandes”︁ von POINCARÉ und ZERMELO. BOLTZMANNS Prinzip bestimmt aber auch die epistemologische und methodologische Bedeutung z. B. der geologischen und paläontologischen Facies als „Dokumente”︁ für die Erdgeschichte.Die Geschichte keines kosmischen Systems ist vollständig aus seiner Eigengesetzlichkeit allein verständlich. Die Systeme entstanden allgemein im Verband eines großen Obsersystems, und ihre Entstehungsgeschichte (z. B. die Kosmogonie der Planeten) ist die Geschichte ihrer Herauslösung aus diesem Obsersystem.Aus diese Weise gelangen wir schließlich zu einer kosmogonischen Hierarchie kosmischer Systeme, und diese zeitartig geordnete Hierarchie ist letztlich äquivalent der räumlichen Hierarchie kosmischer Strukturen, wie sie die „hierarchische Kosmologie”︁ seit KANT und LAMBERT postuliert hat.Das Universum ist eine räumlich und zeitlich nach oben unbeschränkte Hierarchie kosmischer Systeme: Σ0 Σ Σ1 Σ Σ Σ Σ Σ Σ Σ. Daher ist auch die astronomische „Metagalaxis”︁ nur ein System in einer unendlichen Mannigfaltigkeit neben‐ und übergeordneter Strukturen. — In einem Anhang geben wir ein mathematisches Modell für einen solchen „hierarchischen Evolutions‐Kosmos”︁ an, welches aus den kosmologischen Prinzipien der hierarchischen und der relativistischen Kosmologie ableitbar ist.
On the Possibility of a Finite Model Describing the Universe
Authors: Järnefelt G. 
Published: July 2007

AbstractIn his book “The expanding universe” EDDINGTON (1933) suggested the idea of an astronomical world model containing a finite number of material particles. Starting from this idea the author has speculated about the possibility to create a cosmological model where in addition also the number of geometrical points and time‐instants is finite (JÄRNEFELT 1929, 1949, 1951, 1954a, 1954b, 1957, 1964, 1974, JÄRNEFELT and KUSTAANHEIMO 1952, JÄRNEFELT and QVIST 1955). The ultimate goal would be a world model based essentially upon GALOIS fields. In order to explore such a possibility the most simple actually existing physical system, the structure describing a non‐relativistic free particle in an one‐dimensional Euclidean space, is treated here. A discrete representation of this system is outlined and then a GALOIS‐finitization of this platform is discussed. The author suggests that the method presented here for a very special case, could be generalizable and finally extended to a cosmological model.
Variability of emission line spectrum and physical conditions in the nucleus of the seyfert galaxy NGC 1275
Authors: Pronik I. 
Published: July 2007

AbstractThe observational evidences on the variability of relative intensities of emission lines of the Seyfert galaxy NGC 1275 are discussed. The time scale of these variations is about half a year. It equals to the time scale of continuous and radio variations of the nucleus of that galaxy. The changes of the electron temperature Te and the electron density ne calculated from the emission line intensities were found to have a functional connection. This evidences that the physical conditions in the gaseous zone of the nucleus of NGC 1275 are recurrent.
Active nuclei of galaxies
Authors: Dibay E. A. 
Published: July 2007

AbstractThe parameters of fifteen active nuclei are determined from spectroscopic and photometric observations. The values of bolometric luminosity, gas volume and mass, kinetic energy, characteristic dimension and kinematic time‐scale are given. The fluxes of radiative and mechanical energy of the gas envelope are compared. A steady‐state model of the nucleus is proposed with the kinetic energy of the envelope being balanced by the light pressure. The life‐time of the nucleus appears to be of the same order of magnitude as the life‐time of the surrounding galaxy.The broad emission lines suggest to be caused by the gravitational potential of the nucleus. The masses of the central bodies are calculated on this basis. The typical central body mass of an active nucleus is about 108 solar masses. The mass‐luminosity relation is constructed.The steady‐state model seems to explain the optical variability process. Collaps to the center of separate gas clouds, as results of Rayleigh‐Taylor instability, leads to the flares, amplitudes and time‐scales being in agreement with observations.
Cosmogony of galaxies as based on the spatial distribution of matter
Authors: Rudnicki K. 
Published: July 2007

AbstractA morphological box for the space distribution of galaxies and dark matter as the consequence of various types of cosmogonical hypotheses is presented. A short review of concepts of clustering of galaxies is given. One has to distinguish between the phenomena of “clusters of galaxies” and of “clustering of galaxies”. The second notion is more general. The investigations of KIANG, FLIN, and PEEBLES speak in favour of general clustering rather than overal existence of individual clusters. Individuals such as our Supergalaxy, Coma cluster etc. seem rather to be exceptional features.
Polteilchen in der TREDERSchen Tetradentheorie
Authors: Fuchs H. 
Published: July 2007

AbstractIn the framework of TREDERS' tetrad theory of gravitation the interaction of pole‐particles is considered in post‐NEWTONian approximation. The perihelion shift for the two‐body problem is calculated for different matter‐field‐couplings. In general it depends not only from the sum of the masses but also from the reduced mass. The additional term is connected with the absorption of gravitation.
Unusual extinction profiles by RAYLEIGHscattering
Authors: Shah G. A. 
Published: July 2007

AbstractThe extinction efficiencies for small smooth metallic particles (granules) have been calculated using rigorous MIEtheory of scattering. Strong size dependent resonances for spheres composed of sodium, potassium, and calcium have been found. The results seem to have relevance to the problems of interstellar grains especially with reference to structures in the observed extinction curve, diffuse bands and anomaly of cosmic abundances of elements.
Zur Darstellung der anomalen EINSTEIN‐Effekte mit Hilfe einer effektiven Metrik
Authors: Treder H.‐J. , Gottlöber S. 
Published: July 2007

AbstractWir diskutieren die behaupteten Exzesse der gravo‐optischen EINSTEIN‐Effekte an der Sonne. Hierbei unterstellen wir hypothetisch die Signifikanz der in der Literatur behaupteten Anomalien und versuchen, diese mit Hilfe einer effektiven Raum‐Zeit‐Metrik darzustellen, die das formale Modell von dielektrischen Eigenschaften des Vakuums ist. Die effektive Metrik kann so gewählt werden, daß die durch sie bestimmten nichtlinearen elektromagnetischen Effekte mit der Quantenelektrodynamik kompatibel werden.
Small‐Scale Angular Fluctuations of Cosmic Background Radiation. Basic relations
Authors: Dautcourt G. 
Published: July 2007

AbstractA statistical treatment is given of small‐scale angular fluctuations of cosmic background radiation propagating in FRIEDMANN models with Λ= o. It is assumed that the fluctuations arise from
the discrete nature of radiation sources;
density inhomogeneities in continuously distributed radiating matter or from
variable absorption along different light paths towards the observer.
The observable angular correlation function of the intensity fluctuations is expressed in terms of statistical measures of the sources of fluctuations. The rather general formulae are reduced as far as possible without specifying the frequency region.
Réflexions sur la contingence des lois de la Nature
Authors: Boneff N. 
Published: July 2007

AbstractThere are two fundamental conceptions concerning the laws of nature — these laws are eternal or they may vary in the course of time. We suggest an experiment in order to find an intermediary thesis — i.e. to discover that law, if it really exists, according to which a given law of nature varies, or, at least, to find out the direction in which this variation is performed.
An equatorially symmetric rotator model for magnetic stars
Authors: Oetken L. 
Published: July 2007

AbstractSuggested by theoretical and empirical investigations, a very simple magnetic field distribution at the surface of magnetic stars is proposed. This model corresponds to the superposition of a dipole and a quadrupole, both lying in the equatorial plane with their axes in the same direction. The observed variations of the effective magnetic field strength of the sixteen stars investigated can be represented surprisingly well with this model. When the quadrupole contribution is large, the variation of the magnetic field vector over the surface of the star differs characteristically from that of the decentred dipole model; thus the difficulty with the latter, regarding the representation of both the effective magnetic field and the mean surface field with the same parameters may perhaps be avoided.
Discussion of infrared measurements of T Tauri stars and related objects
Authors: Rössiger S. 
Published: July 2007

AbstractIt is at first reported that certain kinds of stars which have been classified as T Tauri stars or related objects are in reality not of this type. After the exclusion of those objects, the infrared measurements accessible in the literature permit to draw some astrophysical inferences. It is then possible to distinguish three classes of light variations. All T Tauri stars have an infrared excess. From the colour indices H – K and K – L it can be deduced that the infrared excess for more than one half of the objects is due to the thermal radiation of the circumstellar dust envelope; for the remaining stars also free‐free radiation from the gas envelope can play an essential part. The largest infrared excesses EH–K were found with the hotter stars (spectral type A) and the strongest emission lines with the cooler stars (spectral types G, K, M). This can finally be explained by the fact that the convection zone in cooler stars reaches far down into their interior than in hotter stars.
Correlation analysis of the space and surface distribution of galaxies
Authors: Dautcourt G. 
Published: July 2007

AbstractThe paper presents a number of calculations which are useful for the interpretation of catalogues of galaxies. It is suggested that a correlation function approach based on a MAYER cluster expansion for the N‐point probability function of galaxies leads to a complete description of galaxy clustering. Other statistical measures of clustering such as the distribution function for the cell population or the distribution of the next neighbour distances are shown to be reducible to a correlation approach. For the classical cell count method smoothing effect estimates are given and the ZWICKY dispersion curve technique is studied. The relation between the space distribution and the surface distribution of galaxies is discussed in cosmological models of FRIEDMANN type. Deviations from PEEBLES' scaling law occur for catalogues extending to faint magnitudes and suggest the existence of strong evolutionary effects in the distribution of galaxies. From the DODD et al. field and the Jagiellonian field one derives — comparing the data with those of the ZWICKY catalogue — that the clustering amplitude decreases like (I + z)‐s within increasing redshift, where s is of the order 6. Since the catalogues extend to small redshifts only, it is not clear if this behaviour continues to larger redshifts. Within the observationally accessible range of z, the value of s does not essentially depend neither on the galaxian luminosity function nor on the deceleration parameter q0, it depends weakly on the assumed K correction.
A thin disc model of the galactic dynamo
Authors: Soward A. M. 
Published: July 2007

AbstractAn axisymmetric αω‐dynamo model of the Galactic disc is investigated. The disc is thin and its width, 2h*, varies slowly with distance, ωT*, from the axis of symmetry. The strength of the α*, varies linearly with axialdistance, z*, while differential rotation, dΩ*/dωT*, remains constant. Otherwise α* and dΩ*/dωT* are arbitrary functions of ωT*. The results are applied to the special case of the oblate spheroid first investigated by STIX (1976) and later by WHITE (1977). In the limit of small aspect ratio the new results agree with those obtained by WHITE and confirm that the dynamo numbers computed by STIX are too small.
A method for reddening determination in the uvby photometric system (Mitteilung der Universitätssternwarte zu Jena Nr. 133)
Authors: Reimann H. G. 
Published: July 2007

AbstractA new method for reddening determination in the uvby system is described. Using a Quby parameter calibrated in terms of b–y it is possible to determine simultaneously luminosity, spectral type, reddening, and metallicity of a star. The colour excess rations for the uvby photometric system are given and also analytical functions for the ZAMS are presented.