A simple model of hillslope response for overland flow generation     

Carmelo Agnese  Giorgio Baiamonte  Cecilia Corrao 《水文研究》2001,15(17):3225-3238

This paper deals with the derivation of the hydrological response of a hillslope on the assumption of quick runoff by surface runoff generation. By using the simple non‐linear storage based model, first proposed by Horton, an analytical solution of the overland flow equations over a plane hillslope was derived. This solution establishes a generalization for different flow regimes of Horton's original solution, which is valid for the transitional flow regime only. The solution proposed was compared successfully with that of Horton and, for the turbulent flow regime, to the one derived from kinematic wave theory. This solution can be applied easily to both stationary and non‐stationary rainfall excess events. An analytical solution for the instantaneous response function (IRF) was also derived. Finally, simple expressions to compute peak and time to peak of IRF are proposed. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Early enrichment of quasars by the first stars     

A. Venkatesan  R. Schneider †  A. Ferrara 《Monthly notices of the Royal Astronomical Society》2004,349(3):L43-L48

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Current confinement in solar coronal loops     

Claudio Chiuderi  Giorgio Einaudi 《Solar physics》1981,73(1):89-103

In this paper solar coronal loops are regarded as regions of localized current flows. The main purpose is to investigate the consequences of current confinement rather than to produce a model. The physical and observational basis for this assumption are presented as well as the connection with previous studies on loop structure. A proper choice of the current profile allows us to treat quantitatively the equilibrium structure of the loops and their MHD and resistive stability properties. Regions of absolute stability against ideal kink modes are found. Explicit growth rates for the tearing-mode instability are computed. The possible relevance of other resistive effects is also discussed and the crucial importance of the small-scale geometry of the magnetic field outlined.  相似文献   

Estimate of the optimum measuring time in the synchronous photometry of optical sources     

Luigia Rusconi  Giorgio Sedmak 《Astrophysics and Space Science》1977,48(1):53-56

The note shows how to estimate accurately the optimum measuring time in the measurement of a periodical optical source by means of a synchronous photometer affected by phase-tracking error. The procedure used can be easily generalized to sources or signal patterns not considered here. The optimum number of scans to be averaged results to be typicallyN _opt≈0.5r/ɛ for an optical source of Lorentzian signal pattern, wherer is the duty cycle of the pulsed component and ɛ the relative truncation error of the local sync to the source period. Work supported by Consiglio Nazionale delle Ricerche, Gruppo Nazionale di Astronomia, Settore Tecnologie Astronomiche. Trieste Observatory — Instruments and Data Processing Group (4/76).  相似文献   

Perturbations of the Kepler Problem in Global Coordinates: A Program     

Bruno Cordani  Giorgio Merlini 《Celestial Mechanics and Dynamical Astronomy》2001,81(4):313-319

The present paper is a brief report of how, along the lines of a previous paper, the implementation of the program KEPLER¹, for the numerical integration of the perturbations of the Kepler problem, has been carried out.  相似文献   

Ground motion and stress accumulation driven by density anomalies in a viscoelastic lithosphere. Some results for the Apennines     

Roberto Sabadini  Giorgio Spada 《Geophysical Journal International》1988,95(3):463-480

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The multifunction photoelectric photometer of Torino Observatory     

Sergio Furlani  Giorgio Sedmak 《Astrophysics and Space Science》1977,48(1):65-78

The paper describes the design and the realization of a multiple-function photoelectric photometer made by Trieste Observatory for Torino Observatory. The system design shows a two-beam, sequential multiband photon counting and analog photoelectric photometer configuration based on a PDP8/E computer for the control and data acquisition and elaboration. The actual realization of the system and the use of it in the one-beam configuration operating now at torino Observatory shows the advantages of such a solution and the easiness in modifying and determining the system functions by software programs rather than by hardware specials. Work supported by Consiglio Nazionale delle Ricerche, Gruppo Nazionale di Astronomia, Settore Tecnologie Astronomiche. The realization of the machine was fully supported by Torino Observatory. Trieste Observatory-Instruments and Data Processing Group (5/76).  相似文献   

Interpreting the transmission windows of distant quasars     

A. Maselli  A. Ferrara  S. Gallerani 《Monthly notices of the Royal Astronomical Society》2009,395(4):1925-1933

We propose the apparent shrinking criterion (ASC) to interpret the spatial extent, R _w, of transmitted flux windows in the absorption spectra of high- z quasars. The ASC can discriminate between the two regimes in which R _w corresponds either to the physical size,   R _{H  ii}   , of the quasar H  ii region or to the distance,   R ^max_w  , at which the transmitted flux drops to  =0.1  and a Gunn–Peterson (GP) trough appears. In the first case [H  ii region (HR) regime], one can determine the intergalactic medium mean H  i fraction,   x _H I  ; in the second [proximity region (PR) regime], the value of R _w allows one to measure the local photoionization rate and the local enhancement of the photoionization rate,  Γ_G  , due to nearby/intervening galaxies. The ASC has been tested against radiative transfer+smoothed particle hydrodynamics numerical simulations, and applied to a sample of 15 high-   z ( z > 5.8  ) quasar spectra. All sample quasars are found to be in the PR regime; hence, their observed spectral properties (inner flux profile, extent of transmission window) cannot reliably constrain the value of   x _{H  i}   . Four sample quasars show evidence for a local enhancement (up to 50 per cent) in the local photoionization rate possibly produced by a galaxy overdensity. We discuss the possible interpretations and uncertainties of this result.  相似文献   

Petrology of Al- and Cr-rich ophiolitic chromitites from the Muğla,SW Turkey: implications from composition of chromite,solid inclusions of platinum-group mineral,silicate, and base-metal mineral,and Os-isotope geochemistry     

İbrahim Uysal  Mahmud Tarkian  M. Burhan Sadiklar  Federica Zaccarini  Thomas Meisel  Giorgio Garuti  Stefanie Heidrich 《Contributions to Mineralogy and Petrology》2009,158(5):659-674

Ultramafic rocks around the city of Muğla in SW Turkey are represented by mantle peridotites depleted to various degrees, ranging from cpx-rich harzburgites to depleted harzburgite and dunite. Cpx-rich harzburgites are thought to be the residua left after extraction of MORB-type basalt, from which high-Al chromitite [49.2 < Cr# = 100 × Cr/(Cr + Al) < 53.5] crystallised with a higher proportion of ¹⁸⁷Os/¹⁸⁸Os (average of 0.1361). However, depleted harzburgites are assumed to be the residua left after extraction of hydrous boninitic melt produced by second stage partial melting of already depleted mantle due to a subducting slab, from which high-Cr chromitites (64.2 < Cr# < 85.9) with lower and heterogeneous ¹⁸⁷Os/¹⁸⁸Os ratio (average of 0.1324) were crystallised as a result of melt–rock interaction in a supra-subduction environment. Dunites around the chromite deposits are considered to be the product of melt–peridotite interaction. Most of the chromitites contain high-Cr chromite and display enrichment in IPGE (Os, Ir, Ru) over PPGE (Rh, Pt, Pd), with PGE concentrations between 61 and 1,305 ppb. Consistently, laurite-erlichmanite series minerals with various Os concentrations are found to be the most abundant PGM inclusions in chromite. Os–Ir–Ru alloy, irarsite, and kashinite, as well as Pt–Fe alloy and Pt-oxide, which are not common in ophiolitic chromitites, were also detected as magmatic PGM inclusions. Pentlandite, millerite, and, rarely heazlewoodite form the magmatic inclusions of base-metal sulphide. The presence of olivine and clinopyroxene, as well as hydrous silicate inclusions such as amphibole and phlogopite, in high-Cr chromitite supports the idea that high-Cr chromitites were formed in a supra-subduction environment.  相似文献   

Beating words to life: subtitles,assemblage(s)capes,expression     

Giorgio Hadi Curti 《GeoJournal》2009,74(3):201-208

Ostensibly, subtitles in films serve as linguistic approximations of meaning. Expectedly then, much of the debate surrounding subtitling has been concerned with representational accuracy, fidelity and authenticity. In this article I argue that by encountering subtitles as affective bodily expressions, as opposed to approximate representations of pre-existent meanings or intentions, filmic experiences may be(come) transformed and differently transformational. As a result, meaning and accuracy in subtitles as superimposed signifiers or static representations become secondary to subtitles as spatially affective- and expressive-movements intimately part of filmic scapes. The creative use of subtitling in Bekmambetov’s Russian language film Night Watch (Nochnoy dozor; 2006 [2004]) is discussed.

Giorgio Hadi CurtiEmail:

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