The iron Kα Compton shoulder in transmitted and reflected spectra     

Giorgio Matt 《Monthly notices of the Royal Astronomical Society》2002,337(1):147-150

We calculate the equivalent width of the core, and the centroid energy and relative flux of the first-order Compton shoulder of the iron Kα emission line from neutral matter. The calculations are performed with Monte Carlo simulations. We explore a large range of column densities for both transmitted and reflected spectra, and study the dependence on the iron abundance. The Compton shoulder is now becoming observable in many objects thanks to the improved sensitivity and/or energy resolution of the XMM – Newton and Chandra satellites, and the present work aims to provide a tool to derive information on the geometry and element abundances of the line-emitting matter from Compton shoulder measurements.  相似文献   

On the use of infinite elements in the analysis of two-dimensional layered elastic systems via discretized integral equations     

Cristina Jommi  Giorgio Novati 《Computers and Geotechnics》1989,8(4):269-288

A boundary integral equation approach is presented for the two-dimensional plane strain analysis of horizontally layered elastic systems resting on a rough and rigid base. The validity of Somigliana identity for unbounded layers is discussed and an Infinite Boundary Element is proposed in order to take into account the lateral unboundedness of the physical problem in the discretized equations. This element is implemented in a computer code based on a successive stiffness solution procedure. A series of numerical tests concerning single- and multi-layered problems is illustrated, and the performance of the proposed solution method is compared with that of more traditional boundary element and finite element techniques.  相似文献   

High Energy Astrophysics with INTEGRAL     

Giorgio G.C. Palumbo 《Astrophysics and Space Science》2001,276(1):325-331

INTEGRAL is an ESA mission scheduled to be launched in 2001. Its fourcoaligned instruments will allow observations of cosmic sources from afraction of a keV to several MeV plus source monitoring in the opticalband. INTEGRAL will be operated as a space observatory and an Announcementof Opportunity to the astronomical community at large will be issued byESA in the spring of the year 2000. Purpose of this paper is to illustrateINTEGRAL capabilities of the three X and Gamma Ray detectors plus opticalmonitor in order to help potential users to write observing proposals.  相似文献   

    

Giuseppe Gambolati  Giorgio Galeati 《Mathematical Geology》1987,19(3):249-257

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Direct,partitioned and projected solution to finite element consolidation models     

Giuseppe Gambolati  Giorgio Pini  Massimiliano Ferronato 《国际地质力学数值与分析法杂志》2002,26(14):1371-1383

Direct, partitioned, and projected (conjugate gradient‐like) solution approaches are compared on unsymmetric indefinite systems arising from the finite element integration of coupled consolidation equations. The direct method is used in its most recent and computationally efficient implementations of the Harwell Software Library. The partitioned approach designed for coupled problems is especially attractive as it addresses two separate positive definite problems of a smaller size that can be solved by symmetric conjugate gradients. However, it may stagnate and when converging it does not prove competitive with a global projection method such as Bi‐CGSTAB, which may take full advantage of its flexibility in working on scaled and reordered equations, and thus may greatly improve its computational performance in terms of both robustness and convergence rate. The Bi‐CGSTAB superiority to the other approaches is discussed and demonstrated with a few representative examples in two‐dimensional (2‐D) and three‐dimensional (3‐D) coupled consolidation problems. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Integrated approach to choosing suitable areas for the realization of productive wells in rural areas of sub-Saharan Africa     

Giorgio Ghiglieri  Alberto Carletti 《水文科学杂志》2013,58(8):1357-1370

Abstract

Comprehensive geological, hydrogeological and hydrogeochemical investigations were carried out in the south of Hodh El Chargui (southeast Mauritania). Obtaining a hydrogeological conceptual model is crucial for groundwater resources development and management. This is especially true in developing countries and in the rural areas of sub-Saharan Africa. The chosen areas are represented by lithologies referring to a long geological time frame, dating from the Upper Neoproterozoic to the Quaternary age. We developed a methodology in order to identify sites that were suitable for the realization of productive, protected and correct wells to supply safe water to the rural community. A multicriteria approach to studying hydrogeology was used in the project area. In order to identify some main areas in which to carry out pilot interventions, criteria relating to water accessibility and availability, and to hydrogeological and water quality, were considered. Moreover, during the project, it was possible to transfer know-how and hand over responsibilities to the local population and bodies.

Citation Ghiglieri, G. & Carletti, A. (2010 Ghiglieri, G., Balia, R., Oggiano, G. and Pittalis, D. 2010. Prospecting for safe (low fluoride) groundwater in the Eastern African Rift: the Arumeru District (Northern Tanzania). Hydrol. Earth System Sci., 14: 1081–1091.  [Google Scholar]) Integrated approach to choosing suitable areas for the realization of productive wells in rural areas of sub-Saharan Africa. Hydrol. Sci. J. 55(8), 1357–1370.  相似文献   

Multi-methodological investigation of kunzite, hiddenite, alexandrite, elbaite and topaz, based on laser-induced breakdown spectroscopy and conventional analytical techniques for supporting mineralogical characterization     

Manuela Rossi  Marcella Dell’Aglio  Alessandro De Giacomo  Rosalba Gaudiuso  Giorgio Saverio Senesi  Olga De Pascale  Francesco Capitelli  Fabrizio Nestola  Maria Rosaria Ghiara 《Physics and Chemistry of Minerals》2014,41(2):127-140

Gem-quality alexandrite, hiddenite and kunzite, elbaite and topaz minerals were characterized through a multi-methodological investigation based on EMPA-WDS, LA-ICP-MS, and laser-induced breakdown spectroscopy (LIBS). With respect to the others, the latter technique enables a simultaneous multi-elemental composition without any sample preparation and the detection of light elements, such as Li, Be and B. The criteria for the choice of minerals were: (a) the presence of chromophore elements in minor contents and/or as traces; (b) the presence of light lithophile elements (Li, Be and B); (c) different crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification and characterization of minerals, and as a fast screening method to determine the chemical composition, including the chromophore and light lithophile elements.  相似文献   

COCHISE: the first light of the Italian millimetre telescope at Concordia (Dome C, Antarctica)     

Lucia Sabbatini  Francesco Cavaliere  Giorgio Dall’Oglio  Antonio Miriametro  Licia Pizzo  Dario Mancini  Guido Torrioli 《Experimental Astronomy》2011,31(2-3):199-214

COCHISE (Cosmological Observations at Concordia with High-sensitivity Instrument for Source Extraction) is a 2.6 m telescope located on the high Antarctic Plateau near the Italian–French Concordia Base. The telescope is mainly devoted to Cosmological observations, able to operate between 200 μm and 3 mm of wavelength. In this paper we describe the main characteristics of the instrument. We also report on the first light, obtained during summer 2010–2011: this result marks the beginning of millimetre astrophysical observations at Concordia. Responsivity, noise equivalent temperature and field of view of the instrument are reported. At present COCHISE is the largest telescope located at Concordia. Beside the scientific expectations, the use of this kind of instrument in the Antarctic environment poses technological aspects of relevant interest: thus COCHISE can be considered as a pathfinder for future Antarctic telescopes.  相似文献   

Reconstruction of hydrocarbons accumulation in sediments affected by the oil refinery industry: the case of Tehuantepec Gulf (Mexico)     

Ana Carolina Ruiz-Fernández  Mario Sprovieri  Mauro Frignani  Joan Albert Sanchez-Cabeza  Maria Luisa Feo  Luca Giorgio Bellucci  Libia Hascibe Pérez-Bernal  Michel Preda  María Luisa Machain-Castillo 《Environmental Earth Sciences》2012,67(3):727-742

The Isthmus of Tehuantepec corresponds to the shortest distance (~200?km) between the Gulf of Mexico and the Pacific Ocean in Southern Mexico, and the main economical activity of this region is oil extraction and refining. Polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs) were determined in a ²¹⁰Pb dated sediment core collected from the continental shelf of Tehuantepec Gulf, in the vicinity of the oil refinery of Salina Cruz, Oaxaca, the main oil refining facility of the country. The sediments were mostly of coarse nature and hence PAHs and TPHs concentrations throughout the core (61?C404???g?g^?1 and 29?C154?mg?kg^?1, respectively) were below international quality benchmarks. Depth profiles of both PAHs and TPHs concentrations showed increasing trends since the early 1900s but the higher values were found from the 1950s to present. PAH congener ratios showed that these contaminants had both petrogenic and pyrolitic sources, although the former has been predominant since the 1970s. The Salina Cruz refinery started operations in 1978 but the oil industry activities in the Tehuantepec Isthmus go back to the beginning of the twentieth century with the operation of Minatitlan refinery in the Gulf of Mexico, and the Gulf of Tehuantepec being the main conduit for oil distribution in the Pacific coast. The observed changes in contaminant distributions described well the oil industry development in the area.  相似文献   

Horizontal rotation signals detected by “G-Pisa” ring laser for the M w = 9.0, March 2011, Japan earthquake     

Jacopo Belfi  Nicolò Beverini  Giorgio Carelli  Angela Di Virgilio  Enrico Maccioni  Gilberto Saccorotti  Fabio Stefani  Alexander Velikoseltsev 《Journal of Seismology》2012,16(4):767-776

We report the observation of the ground rotation induced by the M _w = 9.0, 11th of March 2011, Japan earthquake. The rotation measurements have been conducted with a ring laser gyroscope operating in a vertical plane, thus detecting rotations around the horizontal axis. Comparison of ground rotations with vertical accelerations from a co-located force balance accelerometer shows excellent ring laser coupling at periods longer than 100?s. Under the plane wave assumption, we derive a theoretical relationship between horizontal rotation and vertical acceleration for Rayleigh waves. Due to the oblique mounting of the gyroscope with respect to the wave direction of arrival, apparent velocities derived from the acceleration/rotation rate ratio are expected to be always larger than or equal to the true wave propagation velocity. This hypothesis is confirmed through comparison with fundamental mode, Rayleigh-wave phase velocities predicted for a standard Earth model.  相似文献