121,930 research outputs found
Experimental Measurements Of Air Forced Convection Through Copper Foams
No full textThis paper aims at investigating the air heat transfer and fluid flow through open-cells copper foam samples with different number of pores per unit of length (PPI) with constant porosity (ε=0.93) and foam core height of 40 mm. The experimental heat transfer coefficient and pressure drop measurements were carried out during air forced convection through electrically heated copper foams; the data points are collected in a dedicated test rig. The experimental measurements permit to understand the effects of the pore density on the heat transfer and fluid flow performance of the foams. Present data relative to copper foam samples are compared against present authors experimental measurements for 40 mm high aluminum foams at the same operative test conditions. The paper presents experimental heat transfer coefficients, pressure gradients, permeability, inertia and drag coefficients; moreover, it also reports two meaningful parameters: the normalized mean wall temperature and the pumping power per area density that permit to compare different enhanced surfaces, which can be considered suitable for electronic thermal management
Agglutinated foraminifera from the Epiligurian Succession (Middle Eocene-Lower Miocene, Northern Apennines, Italy): scanning electron microscopic characterisation and paleoenvironmental implications
No full textThe bathyal larger lituolid Neonavarella n. gen. (Foraminifera) from the Thanetian Scaglia Rossa Formation of northeastern Italy
No full textLarger agglutinated foraminifera resembling the Cretaceous genus Navarella Ciry and Rat 1951 were recently recovered in Thanetian hemipelagites from the Belluno Basin, northeastern Italy. These lituoids first appear in the basal Thanetian (uppermost calcareous nannofossils Zone CNP 8) and become common in the >500 μm washed residue from the uppermost Thanetian. They abruptly disappear at the Paleocene/Eocene boundary, in coincidence with the extinction of Paleocene small benthic foraminifera (the benthic foraminiferal extinction event - BEE). In order to document the internal chamber arrangement and the agglutinated wall microstructure of the Thanetian lituolids and to compare them with similar individuals recovered from the Upper Cretaceous and Danian strata of the same section, the collected specimens were sectioned and analyzed using a Scanning Electron Microscope (SEM), equipped with an energy-dispersive X-ray spectrometer (EDX). Our results show a typical bi-layered wall microstructure in the Thanetian specimens, whereas the older Maastrichtian and
Danian specimens, occurring in the same section, display a single, thicker agglutinated wall. The taxonomy of the Italian lituolids is discussed and compared with similar taxa known from the literature.
We describe the Thanetian lituolids as the new genus Neonavarella, which shows an apparently identical external morphology to mono-layered Maastrichtian–Danian specimens but differs in the microstructure of the agglutinated test wall that is bi-layered. The finding of new and well-preserved material from the Paleocene Scaglia Rossa beds of Italy helps shed light on the taxonomy of the still poorly known deep-water larger lituolids
Interferenze fiscali: l’informativa da fornire in nota integrativa. I nuovi adempimenti richiesti dal Principio contabile n. 25 per le poste di stato patrimoniale
No full textLa svalutazione del patrimonio calciatori nel bilancio delle società di calcio professionistiche. Effetti e distorsioni derivanti dall’applicazione delle norme contenute nel decreto «salva-calcio» n. 282/02 convertito in legge
No full textColominella piriniae n. sp.: a new textulariid from the Pliocene Mediterranean record
No full textWe formally describe a new agglutinated foraminiferal species belonging to the genus Colominella Popescu, 1998 (Textulariida) recovered in two Pliocene successions of the western Mediterranean region. The formal description of Colominella piriniae n. sp. here reported permits the known stratigraphical and geographical range of the genus, previously limited to the Badenian (middle Miocene) of the Paratethys, to be extended into the Pliocene of the Mediterranean. The present work points out the importance of microstructural studies performed on sectioned specimens in taxonomic assignments and reviews
Bathyal large lituolids from the Thanetian of northeastern Italy and their extinction at the Paleocene/Eocene boundary
No full textSeveral large agglutinated foraminifera resembling the genus Navarella Ciry & Rat (1951), were recently recovered in middle-lower bathyal Thanetian hemipelagites from the Belluno Basin, northeastern Italy. These navarellids first appear in the basal Thanetian and become quite common in the >500 μm washed residue from the uppermost Thanetian. They abruptly disappear at the Paleocene/Eocene boundary, in coincidence with the extinction of Paleocene cosmopolitan taxa (Benthic Foraminiferal Extinction Event).
Navarella is a large lituolid belonging to the family Ammobaculinidae Saidova 1981 and attaining a maximum length of 5 mm, with a first streptospirally enrolled test, later uncoiled, and with an aperture varying during ontogeny from slit-like to cribrate. The genus was originally described from the Maastrichtian flysch of the Spanish Pyrenees, and then reported elsewhere in Europe from Campanian to Maastrichtian rocks. The validity of this taxon and its range distribution is, however, controversial and strongly debated.
In order to document the internal chamber arrangement and the agglutinated wall microstructure of the Thanetian navarellids and to compare them with similar individuals recovered from the Upper Cretaceous and Danian strata of the same section, the collected specimens were sectioned and analysed using a Scanning Electron Microscope (SEM), equipped with an energy-dispersive X-ray spectrometer (EDX). Our results show a typical bi-layered wall microstructure in the Thanetian specimens, whereas the older Maastrichtian and Danian specimens display a single, thicker agglutinated wall. The taxonomy of the Italian navarellids is discussed and compared with other Navarella-like taxa known in the literature.
Based on available data, we infer that bi-layered navarellids, which are morphologically identical to Maastrichtian-Danian specimens but that differ in their internal microstructure, appeared and developed in the Thanetian but they were eventually driven to extinction during the environmental perturbations associated to the Paleocene-Eocene Thermal Maximum.
We also argue how the finding of new and well-preserved material from the Paleocene Scaglia Rossa beds of Italy may help shed light on both taxonomy and ecological preferences of the still poorly known deep-water lituolids
Paleogeographic evolution and subsidence analysis from micropaleontological constraints: the case of a shared Cenozoic foreland basin
No full textDuring Cenozoic, the Friulian-Venetian Basin (FVB, NE Italy) underwent a complex evolution, related to the inherited Mesozoic sea-bottom topography and the load exerted in different times by the three surrounding belts: the Dinarides to the east, the Southern Alps to the north and the Northern Apennines to the south-west. The location of this basin, at the tectonic knot between the most important Italian hydrocarbon regions (the Po Plain and Adriatic basins), makes the FVB as an interesting case-study from both a scientific and industrial point of view.
The micropaleontological study of foraminiferal assemblages from over 500 samples collected from 13 key wells provides important constraints on the paleobathymetric changes occurred into the basin through time. The reconstructed paleo-water depths together with the sedimentological information derived by the drilled depositional units were used as input in geohistory analysis in order to reconstruct the subsidence/uplift trends affecting different sectors of the FVB as a response to collisional tectonics of three surrounding belts along the basin boundaries.
Results show that the overall depositional architecture of the FVB is the result of six main tectono-depositional phases that occurred at different times and were characterised by paleobathymetric changes and subsidence/uplift trends reflecting both the tectonic control and the balance between subsidence and sediment supply.
In particular, the easternmost sector of the FVB evolved as a Dinaric foredeep during Lutetian time. Since Chattian, a moderate subsidence characterised by faint flexure to the north occurred, which was followed by a Langhian accentuated subsidence phase, consistent with the development of the Southalpine foredeep system. The accommodation space was progressively filled by the sediment flux during Serravallian-Messinian time, as demonstrated by an overall shallowing upward trend recorded in this stratigraphic interval.
A new basin configuration occurred during Piacenzian, when a complex geometry was developed due to the flexural effect of the concurrent loads of the Southern Alps, to the north, and of the Apennines, to the south. Unlike the previous stratigraphic intervals, the Quaternary sedimentary sequence eventually shows a broadly symmetrical geometry with fast and relatively homogeneous subsidence all over the basin, overbalanced by the increased sedimentary supply likely related to the Quaternary climate deterioration
Coherent Dynamics in Solutions of Colloidal Plexcitonic Nanohybrids at Room Temperature
No full textThe increasing ability to prepare systems with nanoscale resolution and address their optical properties with ultrashort time precision is revealing quantum phenomena with tremendous potential in quantum nanotechnologies. Colloidal plexcitonic materials promise to play a pivotal role in this scenario. Plexcitons are hybrid states originating from the mixing of the plasmon resonances of metal nanostructures with molecular excitons. They allow nanoscale confinement of electromagnetic fields and the establishment of strong couplings between light and matter, potentially giving rise to controllable and tunable coherent phenomena. However, the characterization of the ultrafast coherent and incoherent dynamics of colloidal plexciton nanohybrids remains highly unexplored. Here, two dimensional electronic spectroscopy (2DES) is employed to study the quantum coherent interactions active after the photoexcitation of these systems. By comparing the response of the nanohybrids with the one of the uncoupled systems, the nonlinear photophysical processes at the base of the coherent dynamics are identified, allowing a step forward toward the effective understanding and exploitation of these nanomaterials
Assessing the effect of Amphistegina lobifera invasion on infralittoral benthic foraminiferal assemblages in the Sicily Channel (Central Mediterranean)
No full textThis article documents, through a quantitative approach, the negative effect of the highly invasive species Amphistegina lobifera Larsen, 1976 on native benthic foraminiferal assemblages of coastal areas in the Sicily Channel (Central Mediterranean). A nested sampling design was applied through the comparison of benthic foraminiferal community structure across three areas that are known to be at different stages of invasion (i.e. Maltese Islands - advanced, southern Sicily – medium, and eastern Sicily - early). Results suggested that both diversity and richness of benthic foraminiferal community from the Maltese Islands were strongly modified by increased abundances of A. lobifera. In contrast, this phenomenon is less evident in southern and eastern Sicily, where the invader displayed lower abundances and the community structure was more diversified. Collected data also allowed for predicting what could happen in the near future in the whole Sicily Channel, as well as in the rest of the Mediterranean Sea
- …
