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1.
P. Persi M. Ferrari-Toniolo A. R. Marenzi M. Busso L. Corcione M. Marengo M. Tapia 《Astrophysics and Space Science》1995,224(1-2):535-536
We present the results of direct mid-IR images of the luminous young stellar objects GL 2591, S140-IRS1, and W51-IRS2. The sources show an extended mid-IR emission at the limit of our spatial resolution indicating the presence of dense circumstellar dust disks. 相似文献
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The paper discusses a model which predicts the trajectory of floating rigid bodies and may be applied to compute the motion of woody “debris” mobilized during floods. The model couples a Discrete Element (DE) Lagrangian approach for the calculation of motion of rigid bodies with the Eulerian solution of the shallow water equations (SWE), in order to simulate the transport of a cylinder in a two-dimensional stream. It differs from existing models since it is based on a dynamic approach, adapting the Basset–Boussinesq–Oseen equation. In a first step, forces are computed from flow and log velocities; then, the equations of dynamics are solved to model the planar roto-translation of the body. Model results and physical reliability are clearly affected by the values of the drag and side coefficients, especially since logs, modelled as cylinders, are able to change their orientation towards the flow. Experimental studies to evaluate drag and side coefficients can be found in the literature for a submerged cylinder, with various orientations. To extend such results to the case of a floating log, the authors performed a series of laboratory tests on partially submerged cylinders, implementing the outcomes in the proposed DE-SWE model. The coupled model is validated against existing laboratory data concerning spheres and wooden cylinder transport. 相似文献
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N. Epchtein B. De Batz E. Copet P. Fouqué F. Lacombe T. Le Bertre G. Mamon D. Rouan D. Tiphène W. B. Burton E. Deul H. Habing J. Borsenberger M. Dennefeld A. Omont J. C. Renault B. Rocca Volmerange S. Kimeswenger I. Appenzeller R. Bender T. Forveille F. Garzon J. Hron P. Persi M. Ferrari-Toniolo I. Vauglin 《Astrophysics and Space Science》1994,217(1-2):3-9
The DENIS project is the first attempt to carry out a complete digitized survey of the southern sky in the range 1–2.5µm. The main objectives of the programme and the main specifications of the camera and of the data processing stream are briefly outlined 相似文献
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M. Marengo M. Busso P. Persi P.O. Lagage G. Silvestro 《Astrophysics and Space Science》1997,251(1-2):251-254
We present new mid-IR images of AGB and post-AGB circumstellar envelopes (CSEs) obtained with the 10–20 μm imaging camera
CAMIRAS mounted at the TIRGO infrared telescope (Gornergrat, Switzerland). Diffraction limited images of the sources are obtained,
and extended emission for the brightest sources is detected for several arcseconds. Simple radiative transfer modelling is
necessary to fit the observed data and derive the physical and chemical state of the envelope. This kind of analysis is an
important test for dust formation theories, because it gives indications of dust properties along their condensation path
through the envelope.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
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The fractal characteristics of the ultra-low-frequency (ULF) magnetic field variations recorded prior to the Tohoku earthquake (EQ) with M W = 9 which happened on 11 March 2011 are studied in this article with the use of detrended fluctuation analysis and Higuchi fractal dimension algorithm. In the specific study, we use for our calculations only nighttime (LT = 3 a.m. ± 2 h) data because of their lowest contamination by industrial noise. A key aspect of our analysis is the investigation about any possible correlation of the ULF magnetic field variations or their calculated fractal characteristics with geomagnetic indices. Different preprocessing approaches are examined aiming at the minimization of any possible influences from global phenomena in the fractal analysis results, while in the same time retaining the scale-invariant character of ULF magnetic field variations after preprocessing. The obtained fractal analysis results imply locally driven change in the fractal characteristics of the ULF data prior to the Tohoku EQ, which is compatible with the change that has been reported prior to other large EQs. 相似文献
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P. Persi 《Solar physics》1975,43(1):39-47
A new numerical method for the analysis of the high dispersion photospheric spectrum is described. In particular the method is applied to study the C2(0, 0) d 3 Πg-a a Πu molecular band. From measurements of the equivalent widths of C2 lines, a rotational temperature of 4450 ± 305 K is obtained, and the band intensity log W 0 /S 0 = ?0.051 ± 0.101 is found. 相似文献
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P. Persi M. Ferrari-Toniolo A. R. Marenzi M. Busso L. Corcione G. Nicolini K. Shivanandan 《Experimental Astronomy》1994,3(1-4):171-172
We present the main characteristics of a new mid-IR camera, TIRCAM, operating at the 1.5 m Italian Infrared Telescope. 相似文献