Search results for " meccanica"

IL FABBISOGNO D'ENERGIA NELLA COLTURA DEL POMODORO

1990

Meccanica del volo dei velivoli ad ala fissa

2018

La meccanica del volo studia le traiettorie e le caratteristiche del moto di un aeromobile sotto l'azione delle forze aerodinamiche, propulsive e inerziali.

Introduzione all'analisi sperimentale delle tensioni

2009

Introduzione di moderne macchine e tecniche per il mantenimento ed il recupero della viticoltura di Pantelleria

2008

Effects of the Extraction Technology on Pomegranate Juice Quality

2020

Pomegranate juice is a rich source of phenolic components; its consumption has considerably increased throughout the world in recent years, due to its nutraceutical properties. Commercial juice production involves pressing the fruits. The aim of this study was to assess the influence of the pressing stage on pomegranate juice properties, in terms of value, duration of the applied pressure and juice yield in order to examine the influence of pressure level on volatiles and nutraceutical properties of the juice. Pomegranate fruits cv. Wonderful One were manually harvested and mechanically processed for extracting the juice by means of a shelling machine, a peristaltic pump and a pneumatic pre…

Influence of tree's structure on the efficiency of the mechanical harvest of olives

2008

This study represents an analysis about the influence of the structure of the plant and the drupes’ position on the efficiency of the mechanical harvest of olives. The aim is to study the eventual correlations between some geometrical characteristics of the plants and the harvest efficiency. The experimental tests were carried out in an olive grove sited in Castelvetrano, province of Trapani; the variety was Nocellara del Belice, the plants “globe” shaped. Some morphological surveys were carried out on a sample of trees. The mechanical harvest was performed with a trunk shaker provided with an upside down umbrella. After the harvest, the residual production was quantified for each bud in or…

Implicit regulation for automotive variators

2001

A well-known practice uses mechanical variators to realize the so-called continuously variable transmissions (CVTs) for automotive application. A remarkable problem for one of the most used CVTs is given by the hydraulic control of the axial thrust on the half-pulleys that is necessary for torque transmission. It involves a heavy decrease in transmission efficiency. In the present paper, the possible production of the required axial thrust by a simple spring to eliminate hydraulic losses is analysed. It is shown that the power capacity of such a regulated variator is near to the maximum possible, and the belt torque loss is always considerably lower than the sum of the belt and pump losses…

Computational fluid dynamics simulation to evaluate aortic coarctation gradient with contrast-enhanced CT

2014

Coarctation of aorta (CoA) is a narrowing of the aorta leading to a pressure gradient (Delta P) across the coarctation, increased afterload and reduced peripheral perfusion pressures. Indication to invasive treatment is based on values of maximal (systolic) trans-coarctation Delta P. A computational fluid dynamic (CFD) approach is herein presented for the non-invasive haemodynamic assessment of Delta P across CoA. Patient-specific CFD simulations were created from contrast-enhanced computed tomography (CT) and appropriate flow boundary conditions. Computed Delta P was validated with invasive intravascular trans-CoA pressure measurements. Haemodynamic indices, including pressure loss coeffic…

Effect of the Alterations in Contractility and Morphology Produced by Atrial Fibrillation on the Thrombosis Potential of the Left Atrial Appendage

2021

Atrial fibrillation (AF) is a common arrhythmia mainly affecting the elderly population, which can lead to serious complications such as stroke, ischaemic attack and vascular dementia. These problems are caused by thrombi which mostly originate in the left atrial appendage (LAA), a small muscular sac protruding from left atrium. The abnormal heart rhythm associated with AF results in alterations in the heart muscle contractions and in some reshaping of the cardiac chambers. This study aims to verify if and how these physiological changes can establish hemodynamic conditions in the LAA promoting thrombus formation, by means of computational fluid dynamic (CFD) analyses. In particular, sinus …

Head Injury Criterion: mini review

2019

Head Injury Criterion (HIC) is the most important parameter in terms of human survival; it is indicative of brain injuries due to the impact of the head in numerous cases, with a vehicle. This index can be estimated by integrating the resulting acceleration of the head (measured in its gravity center) in a time window