Search results for "Roca"

Selezione e sperimentazione di specie autoctone di potenziale impiego nella fitodepurazione in Sicilia

Numerical simulation of reciprocating turbulent flow in a plane channel

2009

Direct numerical simulation results were obtained for oscillatory flow with zero time mean (reciprocating flow) in a plane channel using a finite volume method, Crank-Nicolson time stepping and central approximation of the advection terms. A pressure gradient varying co-sinusoidally in time was imposed as the forcing term, and its frequency and amplitude were made to vary so as to span a range of regimes from purely laminar to fully turbulent. For the limiting cases of reciprocating laminar flow and steady-state turbulent flow, numerical results were validated against analytical solutions and classic experimental literature data, respectively. For general reciprocating flows, predictions we…

Ventricular Fibrillation and Tachycardia Detection Using Features Derived from Topological Data Analysis

2022

A rapid and accurate detection of ventricular arrhythmias is essential to take appropriate therapeutic actions when cardiac arrhythmias occur. Furthermore, the accurate discrimination between arrhythmias is also important, provided that the required shocking therapy would not be the same. In this work, the main novelty is the use of the mathematical method known as Topological Data Analysis (TDA) to generate new types of features which can contribute to the improvement of the detection and classification performance of cardiac arrhythmias such as Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT). The electrocardiographic (ECG) signals used for this evaluation were obtained from…

Sensitive determination of polycyclic aromatic hydrocarbons in water samples using monolithic capillary solid-phase extraction and on-line thermal de…

2011

A methacrylate-based monolithic capillary column has been evaluated for the preconcentration of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. For this purpose, the monolyte was in situ synthesized in a 6cm×0.32mm id fused-silica capillary. The microextraction unit was fitted to a micro-HPLC pump to pass 10mL of sample. The isolated pollutants were eluted by means of 10μL of methanol, the organic phase being directly collected in a specific interface that can be fitted to the injection port of the gas chromatograph without modification. The interface allows the on-line thermal desorption of the PAHs, avoiding the dilution and providing enough sensitivity to reach …

Ventilation-Perfusion Ratio in Perflubron During Partial Liquid Ventilation

2010

BACKGROUND: Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detec…

Oxygen-carrying v. non-oxygen-carrying colloidal blood substitutes in schock

1982

Loss of more than 10-15 per cent of the circulating blood causes a corresponding fall in filling pressure and a marked reduction in minute volume. In order to combat a fall in the minute volume, catecholamines are liberated, the stimulating components of these cause a rise in vessel tone. In spite of the blood volume being reduced by blood loss, filling pressure and minute volume are restored by compensating mechanisms as long as the volume lost is not enough to exceed the autoregulative capacity. Even with a blood loss of 10-15 per cent, full compensation is not achieved without replenishing the blood volume unless the fluid lost from the vascular bed is less than I0 per cent of the total.…

Analysis of 18 perfluorinated compounds in river waters: Comparison of high performance liquid chromatography–tandem mass spectrometry, ultra-high-pe…

2012

In this work, the performance of ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and capillary liquid chromatography-mass spectrometry (CLC-MS) has been studied for the analysis of eighteen perfluorinated compounds in water samples. UHPLC-MS/MS and CLC-MS analysis were carried out using a Zorbax C-18 column (50 mm × 2.1 mm, 1.8 μm) and a Zorbax SB-C18 column (150 mm × 0.5 mm, 3.5 μm), respectively, in gradient elution mode with a mobile phase of ammonium formate and methanol. Both techniques were compared with conventional LC-MS/MS in terms of speed, sensitivity, selectivity and resolution. Water samples were extracted by solid phase extraction (SPE). Mea…

Distribution and fate of perfluoroalkyl substances in Mediterranean Spanish sewage treatment plants.

2014

The concentrations of 21 perfluoroalkyl substances (PFASs: C4-C14, C16, C18 carboxylates, C4, C6-C8 and C10 sulfonates and C8 sulfonamide) were determined in influent, effluent and sludge from 16 different sewage treatment plants (STPs) located in the Ebro (6), Guadalquivir (5), Jucar (2) and Llobregat (3) Rivers, in two consecutive years (2010 and 2011). The analytes were extracted by solid phase extraction (SPE) and determined by Liquid Chromatography triple Quadrupole Mass Spectrometer (LC-QqQ-MS). All samples, except two sludges from Guadalquivir River STPs, were contaminated with at least one PFAS. Perfluorobutanoate (PFBA), perfluoropentanoate (PFPeA) and perfluorooctane sulfonate (L-…

Perfluorinated Compounds in Food: A Global Perspective

2011

Perfluorinated compounds (PFCs) are resistant to breakdown and are turning up in unexpected places around the world, becoming emerging food contaminants. Although these chemicals have been used in countless products since the 1950s, they have been subject to little control until now. There is still an insufficient knowledge of their sources, occurrence, and hazards for food safety decision making. This article provides a comprehensive review of the food contamination levels and dietary intake risks posed by PFCs, as well as the specific methods developed for their determination. It is based on the evaluation of the published literature between 2004 and the beginning of 2010, with special em…

The buried Fold and Thrust Belt in Sicily: perspectives for future exploration.

2012

The study region is a part of the Sicilian-Maghrebian Fold and Thrust Belt (FTB), a segment of the Alpine collisional belt, recently described as a result of both post-collisional convergence between Africa and Europe and roll-back of the subduction hinge of the Ionian lithosphere. The region (extending in central Sicily from the Madonie Mountains. to the eastern corner of the Iblean-Pelagian foreland through the impressive NE-SW trending Tertiary clastic and evaporitic range of the Caltanissetta trough) is located in an area where the main thrust system disappears beneath a wedge of deformed Neogene deposits. Earlier studies have neglected the importance of the potential target for hydroca…