Інтегро-диференціальні системи псевдопараболічного типу: апріорні оцінки та імпульсно-точкова керованість

Для вольтеррівського інтегро-диференціального оператора псевдопараболічного типу одержано апріорні оцінки у негативних нормах, теореми існування та єдиності узагальнених розв'язків відповідних крайових задач. Розглянуто питання імпульсно-точкової керованості систем, що описуються інтегро-диференціальними псевдопараболічними рівняннями.Для вольтерровского интегро-дифференциального оператора псевдопараболического типа получены априорные оценки в негативных нормах, теоремы существования и единственности обобщенных решений соответствующих граничных задач. Рассмотрен вопрос импульсно-точечной управляемости систем, описываемых интегро-дифференциальными псевдопараболическими уравнениями.For a pseudoparabolic Volterra integro-differential operator, the a priori estimates in negative norms and the unique generalized solvability theorems for the corresponding boundary value problems are obtained. The question of impulse-point controllability of systems governed by pseudoparabolic integro-differential equations is investigated

Three-dimensional VP and VP/VS models of the upper crust in the Friuli area (northeastern Italy)

3-D images of P velocity and P-to S-velocity ratio have been produced for the upper crust of the Friuli area (northeastern Italy) using local earthquake tomography. The data consist of 2565 P and 930 S arrival times of high quality. The best-fitting VP and VP/VS 1-D models were computed before the 3-D inversion. VP was measured on two rock samples representative of the investigated upper layers of the Friuli crust. The tomographic VP model was used for modelling the gravity anomalies, by converting the velocity values into densities along three vertical cross-sections. The computed gravity anomalies were optimized with respect to the observed gravity anomalies. The crust investigated is characterized by sharp lateral and deep VP and VP/VS anomalies that are associated with the complex geological structure. High VP/VS values are associated with highly fractured zones related to the main faulting pattern. The relocated seismicity is generally associated with sharp variations in the VP/VS anomalies. The VP images show a high-velocity body below 6 km depth in the central part of the Friuli area, marked also by strong VP/VS heterogeneities, and this is interpreted as a tectonic wedge. Comparison with the distribution of earthquakes supports the hypothesis that the tectonic wedge controls most of the seismicity and can be considered to be the main seismogenic zone in the Friuli are

Non-Newtonian rheology of crystal-bearing magmas and implications for magma ascent dynamics

The eruptive dynamics of volcanic systems are largely controlled by the viscosity of deforming magma. Here we report the results of a series of high-temperature, high-pressure experiments at conditions relevant for volcanic conduits (250 MPa confining pressure and temperature between 500 °C and 900 °C) that were undertaken to investigate the rheology of magma with crystal fractions varying between 0.5 and 0.8 (50 to 80 wt.%) at different strain-rate conditions. The experiments demonstrate that the presence of crystals increases the relative viscosity (ratio between the viscosity of the mixture and the viscosity of the melt phase) of magmas and additionally induces a decrease of the relative viscosity with increasing strain-rate (shear thinning, non-Newtonian behavior). The experimental results, combined with existing data at low crystal fractions (0–0.3), were used to develop a semi-empirical parameterization that describes the variations of relative viscosity for crystal fractions between 0 and 0.8 and accounts for the complex non-Newtonian rheology of crystal-bearing magmas. The new parameterization, included into numerical models simulating the magma ascent dynamics, reveals that strain-rate-dependent rheology significantly modifies the dynamic behavior inside volcanic conduits, particularly affecting the magma fragmentation conditions

Experimental study of CO2 sequestration by ECBM recovery: the case of Sulcis coal.

An ECBM (Enhanced Coal Bed Methane) feasibility study started for the Sulcis Coal Province (SW Sardinia, Italy) in December 2004: geochemical, structural-geology, stratigraphic and reservoir engineering considerations are discussed. The first newly gathered experimental data are discussed, including: fluid geochemistry (major and minor elements, dissolved gases, C and He isotopic ratios) of the reservoir, coal composition and experimental data on CO2/CH4 adsorption on coal. A MapInfo GIS structure was built up including stratigraphical, geo-structural, hydrogeochemical, coal-compositional and environmental impact information as well as the CO2 sources location and typology. Even if these data could be preliminary with respect to the coal characteritics effectively located at the future injection depth, they highlighted both the challenging positive and negative aspects of the Sulcis Coal Province versus the exploitation of the ECBM technique. The most important objective of this phase I of the project is the selection of the best Sulcis ECBM test-pilot site, which will be followed (Phase II) by the choice of a scaled up site and possibly by a future network (Phase III). These phases are foreseen to be accompanied by the selection of progressively added CO2 industrial sources, to be used within the project economic spreadsheet model, actually in evolution. CO2 geological storage and CH4 production potentials in Sulcis have been grossly evaluated as a whole, in the frame of the Sardinia region CO2 sources, including the coal-fired power plants, both existent and foreseen (hundreds of millions of tonns of CO2 are possible to be stored underground in the next decades). The reservoir estimates, both for the CO2 injection and for the CH4 production are clearly involving to start the test-site phase exploitation, in the frame of an auspicabile international operative project

The effect of PCO2 on the high temperature behavior of dolomite: insights from deformation experiments.

see Abstract Volum

Ultime novit\ue0 nello studio dei tessuti connettivi mutabili (MCTs) : un approccio biochimico e biomolecolare in Paracentrotus lividus

I tessuti connettivi collageni sono ubiquitari nel regno animale e svolgono funzioni di protezione, supporto, immagazzinamento dell'energia elastica e trasferimento di tensione. Gli echinodermi posseggono un peculiare tipo di tessuto connettivo mutabile (MCT), in grado di andare incontro a rapidi cambiamenti delle intrinseche propriet\ue0 meccaniche, mediati dal sistema nervoso, fenomeno noto come mutabilit\ue0. Date queste premesse, gli MCTs possono quindi rappresentare una fonte di ispirazione per biomateriali indirizzati ad esempio all'applicazione biomedica. Le principali componenti extracellulari degli MCTs sono rappresentate da: fibrille di collagene, fibrillina, proteoglicani e glicoproteine, in particolare stiparina e tensilina, che modulano l\u2019aggregazione delle fibrille collagene e le loro possibilit\ue0 di slittamento reciproco, stabilendo legami interfibrillari. Scopo del presente lavoro \ue8 stato mettere a punto un protocollo di estrazione biochimica del collagene dagli MCTs del riccio di mare Paracentrotus lividus, e di purificazione e quantificazione del collagene estratto. Inoltre, dati preliminari sono stati ottenuti con riferimento alla caratterizzazione biomolecolare della tensilina. Il fine ultimo sar\ue0 testare le propriet\ue0 di modulazione da parte della tensilina sullo stato di aggregazione sul collagene estratto a diversi gradi di purezza

New insight into mutable collagenous tissue : work in progress and applied perspectives in Paracentrotus lividus

The mechanically adaptable connective tissue of echinoderms (Mutable Collagenous Tissue, MCT), which can undergo drastic nervously-mediated changes in stiffness, tensile strength and viscosity, represents a promising model for biomaterial design and biomedical applications. MCT could be a source of inspiration for new composite materials whose molecular interactions and structural conformation can be changed in response to external stimuli. MCT is composed of collagen fibrils comparable to those of mammals plus other fibrillar structures, proteoglycans and glycoproteins. According to literature, the extracellular matrix of holothurians includes at least two glycoproteins, stiparin and tensilin, that can modulate the aggregation of collagen fibrils and their capacity for reciprocal sliding. This contribution presents the latest results of a detailed analysis of MCT components in Paracentrotus lividus: focusing on biochemical characterization of the fibrillar components (extraction, purification and quantification) and biomolecular analysis of the glycoprotein components. The final aims will be to confirm the presence and the role of these glycoproteins in echinoids and to manipulate simpler components in order to produce a composite with mutable mechanical properties. In the long term, MCT could provide inspiration for biomimetic materials and offer great potential for economically relevant biotechnological and clinical applications that require the controlled and reversible plasticization and/or stiffening of connective tissue

New insights into the mutable collagenous tissue of Paracentrotus lividus : preliminary results

The mechanically adaptable connective tissue of echinoderms (Mutable Collagenous Tissue\u2014MCT), which can undergo drastic nervously-mediated changes in mechanical properties, represents a promising model for biomaterial design and biomedical applications. MCT could be a source of, or an inspiration for, new composite materials whose molecular interactions and structural conformation can be changed in response to external stimuli. MCT is composed mostly of collagen fibrils, comparable to those of mammals, plus a variety of other components, including other fibrillar structures, proteoglycans and glycoproteins. This contribution presents the preliminary results of a detailed analysis of MCT components in the sea-urchin Paracentrotus lividus, focusing on biochemical characterization of the fibrils and biomolecular analysis of the presumptive glycoproteins involved. The final aims will be to confirm the presence and the role of these glycoproteins in echinoids and to manipulate simpler components in order to produce a composite with mutable mechanical properties

East and west separation of Rhipicephalus sanguineus mitochondrial lineages in the Mediterranean Basin

Background: Rhipicephalus sanguineus belongs to a complex of hard tick species with high veterinary-medical significance. Recently, new phylogenetic units have been discovered within R. sanguineus, which therefore needs taxonomic revision. The present study was initiated to provide new information on the phylogeography of relevant haplotypes from less studied regions of Europe and Africa. With this aim, molecular-phylogenetic analyses of two mitochondrial markers were performed on 50 ticks collected in Hungary, the Balkans, countries along the Mediterranean Sea, Kenya and Ivory Coast. Results: In the "temperate lineage" of R. sanguineus, based on cytochrome c oxidase subunit 1 (cox1) and 16S rRNA genes, Rhipicephalus sp. I was only found in the eastern part of the Mediterranean Basin (with relatively homogenous haplotypes), whereas Rhipicephalus sp. II occurred in the middle-to-western part of this region (with phylogenetically dichotomous haplotypes). Ticks identified as R. leporis (based on morphology and cox1 gene) were found in Kenya and Ivory Coast. These clustered phylogenetically within R. sanguineus (s.l.) ("tropical lineage"). Conclusions: In the Mediterranean Basin two mitochondrial lineages of R. sanguineus, i. e. Rhipicephalus sp. I and Rhipicephalus sp. II exist, which show different geographical distribution. Therefore, data from this study confirm limited gene flow between Rhipicephalus sp. I and Rhipicephalus sp. II, but more evidence (analyses of nuclear markers, extensive morphological and biological comparison etc.) are necessary to infer if they belong to different species or not. The phylogenetic relationships of eastern and western African ticks, which align with R. leporis, need to be studied further within R. sanguineus (s.l.) ("tropical lineage")

Shear wave velocity prediction using seismic attributes and well log data

Formation’s properties can be estimated indirectly using joint analysis of compressional and shear wave velocities. Shear wave data isnot usually acquired during well logging, which is most likely for costsaving purposes. Even if shear data is available, the logging programs provide only sparsely sampled one-dimensional measurements: this informationis inadequate to estimate reservoir rock properties. Thus, if the shear wave data can be obtained using seismic methods, the results can be used across the field to estimate reservoir properties. The aim of this paper is to use seismic attributes for prediction of shear wave velocity in a field located in southern part of Iran. Independent component analysis(ICA) was used to select the most relevant attributes to shear velocity data. Considering the nonlinear relationship between seismic attributes and shear wave velocity, multi-layer feed forward neural network was used for prediction of shear wave velocity and promising results were presented