1,721,118 research outputs found
Preface to "A Selection of Papers Presented at the 5th Euro-Mediterranean Symposium on Laser Induced Breakdown Spectroscopy (EMSLIBS 2009)"
No full textPhase behaviour of polydisperse sticky hard spheres: analytical solutions and perturbation theory
No full textWe discuss the phase coexistence of polydisperse colloidal suspensions in the presence of adhesion forces. The combined effect of polydispersity and Baxter's sticky-hard-sphere (SHS) potential, describing hard spheres interacting via strong and very short-ranged attractive forces, give rise, within the Percus–Yevick (PY) approximation, to a system of coupled quadratic equations which, in general, cannot be solved either analytically or numerically. We review and compare two recent alternative proposals that have attempted to by-pass this difficulty. In the first, truncating the density expansion of the direct correlation functions, we have considered approximations simpler than the PY one. These Cn approximations can be systematically improved. We have been able to provide a complete analytical description of polydisperse SHS fluids using the simplest two orders C 0 and C 1. Such a simplification comes at the price of a lower accuracy in the phase diagram, but has the advantage of providing an analytical description of various new phenomena associated with the onset of polydispersity in phase equilibria (e.g., fractionation). The second approach is based on a perturbative expansion of the polydisperse PY solution around its monodisperse counterpart. This approach provides a sound approximation to the real phase behaviour, at the cost of considering only weak polydispersity. Although a final determination of the soundness of the latter method would require numerical simulations for the polydisperse Baxter model, we argue that this approach is expected to correctly take into account the effects of polydispersity, at least qualitatively
Alpine structure and deformation chronology at the Southern Alps - Po plain border in Lombardy
No full textA review of the structural grain of Southern Alps in Lombardy is here integrated with new subsurface data, in order to contribute to detailed reconstruction of the chronology of Alpine deformation of the South Alpine chain and foreland. According to the recent structural schemes, we firstly describe the northern structural zones of the mountain belt. From N to S these are: the Orobian Thrust, involving Variscan basement and Permian sedimentary cover; the Orobian Anticlines, which include basement to lower Mesozoic units (DE SITTER & DE SITTER KOOMANS, 1949); the Carbonate Allochthonous Units, forming a stack of imbricated thrusts of Mesozoic formations (GAETANI & JADOUL, 1979); the Flessura Pedemontana (DESIO, 1929), which involves the South Alpine succession up to the Cretaceous formations in an out of sequence, thrust-related fold belt of late Neoalpine age; the Structures of the South Alpine border (BERSEZIO et alii, 2001), which represent the southernmost marginal belt of faulted folds involving mostly the Cretaceous Lombardian Flysch. Secondly we describe three structural belts, which can be recognised at the buried front of Southern Alps and in the Po Plain foreland area: the Imbricate Tertiary Units BERSEZIO et alii, 2001), which involve the Mesozoic and Tertiary successions, the former underlying at great depth the stack of imbricated Tertiary clastic wedges; the Structures of the Central Lombardy plain (BERSEZIO et alii, 2001), a belt of regional folds due to propagation of deep fault planes ramping up from the metamorphic basement of the Po Plain; the Southernmost Po Plain Structures, which are represented by gentle folds affecting the Tertiary clastic wedges at the southern tip of the South Alpine thrusts. Analysis of deformation chronology has allowed us to identify the structures predating the Adamello magmatic intrusion (older than 42 Ma), both in the mountain chain (Orobic thrust) and in the foreland (inversion structures of the Lacchiarella and Villafortuna- Trecate areas), where Pre-Adamello foreland deformation is represented by gentle inversion of the pre-Cretaceous extensional basins. Post-Adamello (Neoalpine) deformation is responsible for foreland propagation of the thrust belt, with formation of the Imbricate Tertiary Units, which are kinematically linked with the Structures of the South Alpine border. Their deformation lasted until the Tortonian, as documented by preservation of Tortonian sediments in the footwall of the most external South Alpine thrusts. Neoalpine strong inversion of the Mesozoic basins occurred in the southernmost Po plain foreland. In the most external foreland area of the western Southern Alps (Piedmont-Lombardy area), Neoalpine compression came to an end after deposition of the Lower Messinian units and reasonably before the Pliocene. However, east of the Giudicarie line, South Alpine deformation lasted until the Pleistocene
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Fluids of Spherical molecules with dipolarlike nonuniform adhesion: An analytically solvable anisotropic model
No full textWe consider an anisotropic version of Baxter’s model of “sticky hard spheres,” where a nonuniform adhesion is implemented by adding, to an isotropic surface attraction, an appropriate “dipolar sticky” correction (positive or negative, depending on the mutual orientation of the molecules). The resulting nonuniform adhesion varies continuously, in such a way that in each molecule one hemisphere is “stickier” than the other. We derive a complete analytic solution by extending a formalism [M. S. Wertheim, J. Chem. Phys. 55, 4281 (1971)] devised for dipolar hard spheres. Unlike Wertheim’s solution, which refers to the “mean spherical approximation,” we employ a Percus-Yevick closure with orientational linearization, which is expected to be more reliable. We obtain analytic expressions for the orientation-dependent pair correlation function g(1,2). Only one equation for a parameter K has to be solved numerically. We also provide very accurate expressions which reproduce K as well as some parameters, Λ1 and Λ2, of the required Baxter factor correlation functions with a relative error smaller than 1%. We give a physical interpretation of the effects of the anisotropic adhesion on the g(1,2). The model could be useful for understanding structural ordering in complex fluids within a unified picture
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Architecture of the western margin of the North Adriatic foreland: the Schio-Vicenza fault system
No full textIn the Italian Southern Alps, the Lombardic and Venetian
chains and related foreland are separated by the Lessini-Berici- Euganei foreland block, which is unaffected by the Neogene-Quaternary shortenings. However, the Veneto-Friuli alluvial plain to the east of this foreland block has been affected by a poly-phase evolution since the Mesozoic era and represents the foreland of three surrounding chains. The area was affected by several flexural cycles related to the diachronous build-up of the External Dinarides to the
east (Late Cretaceous-Late Eocene), the Eastern Southern Alps to the north (Late Oligocene-Quaternary), and the Northern Apennines to the southwest (Middle Miocene-Quaternary). The last two chains are currently active, although at different rates. The western margin of the foreland is marked by the Schio-Vicenza fault, which divides the deformed foreland (Veneto-Friuli alluvial plain) from the undeformed foreland (Lessini and Berici Mountains and Euganei Hills). The aim of this work is to unravel the architecture and evolution of this boundary using 2D seismic sections and deep wells acquired by ENI for hydrocarbon exploration. Approximately 1,000 km of seismic
lines were interpreted and 10 wells were used to calibrate the seismic interpretation. Seven seismic sections that are sub-orthogonal to the main faults were selected to obtain geological cross-sections through a depth conversion process. The collected data display a complex buried fault system (Schio-Vicenza fault system) that extends with a NW-SE trend from the foot of the Prealps to the Po Delta. In the
cross sections, the movement of the fault shows a vertical component with down-throw of its eastern side (hanging wall block). Some faults display a Mesozoic extensional displacement in accordance with the Mesozoic basin and swell architecture of the area. In addition, the Pliocene throw increases from the southeast to the northwest.
Therefore, the Schio-Vicenza fault system can be interpreted as an inherited Mesozoic structure that reactivated during the Neogene shortening of the area. In particular, this fault system appears to have been mainly active during the Pliocene-Quaternary flexural cycle that is related to the Northern Apennines subduction, which is when the fault system accommodated a scissor movement between
the Veneto-Friuli foreland and the Lessini-Berici-Euganei block
Tectonostratigraphic evolution of the Jurassic extensional basins of the eastern southern Alps and Adriatic foreland based on an integrated study of surface and subsurface data
No full textSuccessions that characterize the eastern southern Alps have
been compared with coeval units drilled in the Alpine foreland
(Po and Veneto plains, northernAdriatic Sea). The eastern
southern Alps are composed of a carbonate platform-plateau,
drowned in the Early Jurassic (Trento platform and plateau);
a basin formed in the Early Jurassic (Belluno Basin) and a carbonate
platform that lasted from the Jurassic to the Cretaceous
(Friuli platform). Integration of stratigraphic and geophysical
data illustrates the extensional architecture of the Alpine foreland
subsurface. At the beginning of the Jurassic, peritidal successions
were widespread everywhere except for the Belluno
Basin. A reorganization of the Early Jurassic paleogeography affected
the southern Alps around the Sinemurian–Pliensbachian
boundary: the Pliensbachian successions were deposited in the
central-western areas of the Trento platform whereas, elsewhere
in the same platform and in the northern Friuli platform,
Pliensbachian units are missing, replaced by an unconformity
surface covered by crinoidal sands that have also been
found in the subsurface. The Belluno Basin is recognizable in
seismic profiles under the Veneto Plain. Southward (northern
Adriatic Sea and Po plain), the basin between the Trento and
the Friuli platforms, here called the “northern Adriatic Basin,”
possesses a stratigraphy different from that of the Belluno
Basin. The northern Adriatic Basin drowned later, and seismic profiles indicate that it was wider and bounded by groups of
small synsedimentary faults instead of the major faults displacing
the Belluno Basin. The northernAdriatic Basin can be interpreted
as the northeastern extension of the Umbro-Marchean Basin of
central Italy
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