Le possibilita' minerarie della Provincia di Messina     

Mario Bossolasco  Dr. Ing. minerario Alberto Bonetti 《Pure and Applied Geophysics》1940,2(1):60-71

Riassunto Premessi alcuni richiami sulle caratteristiche geologiche della Provincia di Messina, si illustrano le possibilità minerarie della regione in base specialmente alle indagini eseguite dal R. Istituto Geofisico e Geodetico di Messina. Dal relativo esame consegue l'importanza delle manifestazioni di minerali metallici con giacimenti che possono assicurare una produzione notevole—sopratutto per il rame, ma anche il piombo, antimonio, zinco, ferro, ecc.—nonostante la distribuzione complessa ed irregolare delle mineralizzazioni. In pari tempo sono segnalate altresi le sicure possibilità di un conveniente sfruttamento degli scisti bituminosi, delle ligniti, nonchè di altri materiali (fluorite, caolino,...) di cui è dotato il sottosuolo della Provincia di Messina.

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Zusammenfassung Nach der Untersuchungen des R. Istituto Geofisico e Geodetico zu Messina werden die bergbauwürdigen Lagerstätten der Messina-Provinz beschrieben und erörtet. Das geschieht unter einer allgemeinen Erwähnung der geologischen Bedingugen. Dazu lässt sich zeigen, wie die Messina-Provinz besonders reich an Erz-Lagerstätte ist, vor allem an Kupfer-Erze, weiter auch an Blei-, Antimon-, Zink-, Eisen-Erze, usw, obwohl die Verteilung einigermassen kompliziert und ungleichmässig ist. Auch die bauwürdigen Lagerstätten der anderen Materialen, wie bituminose Schiefer, Braunkohlen, usw werden erwähnt.

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Résumé Après un bref rappel des caractères géologiques de la Province de Messina, on documente les possibilités minières de la région surtout à la suite des recherches faites par l'Istituto Geofisico e Geodetico di Messina. De l'examen rélatif dérive l'importance des maniféstations en mineraux métalliques, avec gisements capables de donner une production convenable—particulièrement de cuivre, mais aussi de plomb, d'antimoine, de zinc, de fer, etc,—malgré la distribution complexe et irrégulière des minéralisations. On mentionne aussi les autres possibilités d'exploitation des gîtes de schistes bitumineuses, de lignites et d'autres matériaux.

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On-line identification and convergence analysis of excitation-force and drag-force models for moored floating structures     

Mario Alberto Jordn 《Ocean Engineering》2006,33(8-9):1161-1213

This work presents an approach to identify hydrodynamic models for incident, diffraction and viscous forces acting on a moored floating structure. An important aspect treated here is the analysis of the unknown initial condition of the hydrodynamic state for the potential-radiation force. There is established its influence on the parameter convergence and the long-term effects. Afterwards the persistency of excitation of the regressor is analyzed in the case of both poor and rich excitation conditions. Theoretical results show that asymptotic convergence of the estimates takes place under arbitrary conditions of the wave excitation. A case study consisting in the identification of a moored semisubmersible is carried out to exemplify the application of the approach.  相似文献   

Solving Kepler’s Equation using Bézier curves     

Daniele Mortari  Alberto Clocchiatti 《Celestial Mechanics and Dynamical Astronomy》2007,99(1):45-57

This paper presents a non-iterative approach to solve Kepler’s Equation, M = E − e sin E, based on non-rational cubic and rational quadratic Bézier curves. Optimal control point coordinates are first shown to be linear with respect to orbit eccentricity for any eccentric anomaly range. This property yields the development of a piecewise (e.g., 3, 4) solving technique providing accuracies better than 10⁻¹³ degree for orbit eccentricity e ≤ 0.99. The proposed method does not require large pre-computed discretization data, but instead solves a cubic/quadratic algebraic equation and uses a single final Halley iteration in only a few lines of code. The method still provides accuracies better than 10⁻⁵ degree for the near parabolic worst case (e = 0.9999) with very small mean anomalies (M < 0.0517 deg). The complexity of the proposed algorithm is constant, independent of the parameters e and M. This makes the method suitable for extensive orbit propagations. Presented at the 7th Dynamics and Control of Systems and Structures in Space Conference, July 18–22, 2006, Greenwich, England.  相似文献   

Asteroid 2002NY40 as a source of meteorite-dropping bolides     

Josep M. Trigo-Rodríguez  Esko Lyytinen  Daniel C. Jones  José M. Madiedo  Alberto J. Castro-Tirado  Iwan Williams  Jordi Llorca  Stanislav Vítek  Martin Jelínek  Blanca Troughton  Francisco Gálvez 《Monthly notices of the Royal Astronomical Society》2007,382(4):1933-1939

The existence of asteroidal meteoroid streams capable of producing meteorite-dropping bolides has long being invoked, but evidence is scarce. Recent modelling of previously reported associations suggests that the time-scales to keep the orbital coherence of these streams producing meteorites are too short. We present an unequivocal association between near earth object (NEO) 2002NY40 and at least one bright fireball detected over Finland in 2006 August. Another two additional fireballs recorded from Spain and Finland seem to be related, together producing a fireball-producing stream (β Aquarids). On the basis of historical data, the 2006 finding suggests the existence of a meteoroid complex capable of producing meteorites. Taking into account present time-scales for orbital decoherence, if 2002NY40 has large meteoroids associated with it, such behaviour would be the consequence of a relatively recent asteroidal fragmentation. Supporting our claim, the heliocentric orbits of two recently discovered NEOs, 2004NL8 and 2002NY40, were found to exhibit a good similarity to each other and also to the orbits of the three bolides. The fireball spectra of the two Finish bolides showed that the chemical abundances of these objects are consistent with the main elements found in chondrites. This result is consistent with the probable Low iron, Low metal (LL) chondritic mineralogy of asteroid 2002NY40. Consequently, this asteroid may be delivering LL chondrites to the Earth. Additional fireball reports found in the literature suggest that the associated β Aquarid complex may have been delivering meteorites to the Earth during, at least, the last millennium.  相似文献   

Convergence in a thermally softened thick crust: Variscan intracontinental tectonics in Iberian plate rocks     

Sergio Llana‐Fúnez  Alberto Marcos 《地学学报》2007,19(6):393-400

The subduction phase in the development of the Variscan Orogen in SW Europe was followed by an extended period of ‘intracontinental’ tectonics. The progressive temperature rise in the hinterland during plate convergence was accompanied by widespread partial melting in the lower crust and the nucleation of kilometric buckle folds and crustal‐scale shear zones in the stronger upper crust. Thermal mechanical weakening in the core of the orogen was contemporaneous with shortening and thickening in the foreland fold‐and‐thrust belt. We evaluate lithospheric strength profiles in the hinterland and foreland based on the metamorphic and structural record for three tectonic stages. We find that lower crustal strength varied in space as well as in time during orogenesis. Strength contrasts between the foreland and the hot hinterland during convergence may have led to the additional indentation of the foreland into the hinterland of the Ibero‐Armorican Arc.  相似文献   

Probability-weighted hazard maps for comparing different flood risk management strategies: a case study   总被引：5，自引：1，他引：4  

Giuliano Di Baldassarre  Attilio Castellarin  Alberto Montanari  Armando Brath 《Natural Hazards》2009,50(3):479-496

The study proposes an original methodology for producing probability-weighted hazard maps based on an ensemble of numerical simulations. These maps enable one to compare different strategies for flood risk management. The methodology was applied over a 270-km² flood-prone area close to the left levee system of a 28-km reach of the river Reno (Northern Central Italy). This reach is characterised by the presence of a weir that allows controlled flooding of a large flood-prone area during major events. The proposed probability-weighted hazard maps can be used to evaluate how a structural measure such as the mentioned weir alters the spatial variability of flood hazard in the study area. This article shows an application by constructing two different flood hazard maps: a first one which neglects the presence of the weir using a regular levee system instead, and a second one that reflects the actual geometry with the weir. Flood hazard maps were generated by combining the results of several inundation scenarios, simulated by coupling 1D- and 2D-hydrodynamic models.  相似文献   

First Record of Hoplictis(Carnivora,Mustelidae) in East Asia from the Miocene of the Ulungur River Area,Xinjiang,Northwest China     

Alberto VALENCIANO  JIANGZUO Qigao  WANG Shiqi  LI Chunxiao  ZHANG Xiaoxiao  YE Je 《《地质学报》英文版》2019,93(2):251-264

The first unequivocal remains of medium to large-sized mustelids from the middle Miocene Halamagai and Kekemaideng formations have been found in the Ulungur River area, Xinjiang, northwestern China. These new fossils are referred to the hypercarnivorous mustelid Hoplictis Ginsburg, 1961 and denote the first record of the genus in East Asia.We define Hoplictis baihu n. sp., for the mustelid from Tieersihabahe(Halamagai Fm.), which represents the smallest species of the genus. This primitive form is closer to H. florancei and H. noueli than to H. anatolicus and later, larger and more derived Hoplictis spp., from Europe and North America. A large toothless mandible from Duolebulejin(Kekemaiden Fm.) is assigned to Hoplictis cf. helbingi, and it presumably might represent the first record of H. helbingi outside Western Europe. The systematic position of Hoplicitis in relation to Ischyrictis with which it is similar is clarified. The occurrence in East Asia of two species of Hoplictis greatly expands the known distribution and diversity of the genus, and supports a Palaearctic Neogene dispersal event of carnivorans between Europe and Asia during the late Shanwangian–early Tunggurian equivalent to MN5–6 in Europe, and indication of another dispersal event from Europe to North America,through Northwest China during the late Tunggurian, equivalent to MN7–8 in Europe.  相似文献   

GIS technology and models for assessing landslide hazard and risk   总被引：8，自引：1，他引：7  

Alberto Carrara  Richard J. Pike   《Geomorphology》2008,94(3-4):257

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Mechanisms controlling the air–sea flux in the North Sea     

A.E.F. Prowe  Helmuth Thomas  Johannes Ptsch  Wilfried Kühn  Yann Bozec  Laure-Sophie Schiettecatte  Alberto V. Borges  Hein J.W. de Baar 《Continental Shelf Research》2009,29(15):1801-1808

The mechanisms driving the air–sea exchange of carbon dioxide (CO₂) in the North Sea are investigated using the three-dimensional coupled physical–biogeochemical model ECOHAM (ECOlogical-model, HAMburg). We validate our simulations using field data for the years 2001–2002 and identify the controls of the air–sea CO₂ flux for two locations representative for the North Sea's biogeochemical provinces. In the seasonally stratified northern region, net CO₂ uptake is high () due to high net community production (NCP) in the surface water. Overflow production releasing semi-labile dissolved organic carbon needs to be considered for a realistic simulation of the low dissolved inorganic carbon (DIC) concentrations observed during summer. This biologically driven carbon drawdown outcompetes the temperature-driven rise in CO₂ partial pressure (pCO₂) during the productive season. In contrast, the permanently mixed southern region is a weak net CO₂ source (). NCP is generally low except for the spring bloom because remineralization parallels primary production. Here, the pCO₂ appears to be controlled by temperature.  相似文献   

Application of a barrier island translation model to the millennial-scale evolution of Sand Key,Florida     

Riccardo Masetti  Sergio Fagherazzi  Alberto Montanari 《Continental Shelf Research》2008

The evolution of a barrier island and its stratigraphic architecture is investigated with the numerical model BIT (barrier island translation). The model simulates, with simplified equations, the effects of various processes (wind waves, storm surges, sea-level oscillations) on sediment location and characteristics. The presented formulation is able to reproduce both the cross-shore profile and the distribution of sediment facies in time.  相似文献