Search results for " meccanica"

Application of Precision Agriculture for the Sustainable Management of Fertilization in Olive Groves

2023

Olive tree growing (Olea europaea L.) has considerably increased in the last decades, as has the consumption of extra virgin olive oil in the world. Precision agriculture is increasingly being applied in olive orchards as a new method to manage agronomic variability with the aim of providing individual plants with the right input amount, limiting waste or excess. The objective of this study was to develop a methodology on a GIS platform using GEOBIA algorithms in order to build prescription maps for variable rate (VRT) nitrogen fertilizers application in an olive orchard. The fertilization plan was determined for each tree by applying its own nitrogen balance, taking into account the variab…

Electrical Conduction in Carbon Nanotubes under Mechanical Deformations

2009

The enormous potential of carbon nanotubes (CNTs) as primary components in electronic devices and NEMS necessitates the understanding and predicting of the effects of mechanical deformation on electron transport in CNTs. In principle, detailed atomic/electronic calculations can provide both the deformed configuration and the resulting electrical transport behavior of the CNT. However, the computational expense of these simulations limits the size of the CNTs that can be studied with this technique and a direct analysis of CNTs of the dimension used in nano-electronic devices, particularly multi-wall CNTs (MWNTs), seems prohibitive at the present. Here a computationally effective mixed finit…

Simulation of the electromechanical behavior of multiwall carbon nanotubes.

2009

The enormous potential of carbon nanotubes (CNTs) as primary components in electronic devices and NEMS necessitates the understanding and predicting of the effects of mechanical deformation on electron transport in CNTs. In principle, detailed atomic/electronic calculations can provide both the deformed configuration and the resulting electrical transport behavior of the CNT. However, the computational expense of these simulations limits the size of the CNTs that can be studied with this technique, and a direct analysis of CNTs of the dimension used in nanoelectronic devices seems prohibitive at the present. Here a computationally effective mixed finite element (FE)/tight-binding (TB) appro…

Modello numerico per la caratterizzazione elettromeccanica dei nanotubi di carbonio

2016

Nell’ultimo decennio i nanotubi di carbonio (Carbon nanotubes, CNTs) hanno suscitato un considerevole interesse nella comunità scientifica internazionale a causa delle loro proprietà meccaniche, bassa densità ed elevata conducibilità termica. I CNT possiedono inoltre peculiari proprietà elettroniche dipendenti da elicoicità e stato di deformazione, rendendoli potenziali elementi costruttivi di una nuova tecnologia nano-elettronica. Numerosissimi dispositivi elettronici basati sui CNTs (transistors, nano-switches, attuatori, ecc.) sono già stati realizzati. Un nuovo approccio è stato sviluppato per investigare la deformazione dei CNTs e si basa su modelli agli elementi finiti accuratamente s…

Indentation of rigidly supported sandwich beams with foam cores exhibiting non-linear compressive behaviour.

2011

A generalized analytical approach to investigate the indentation of sandwich beams under concentrated loads is presented, based on the Winkler foundation theory. A segment-wise model is implemented to the case of fully backed sandwich beams with polymeric foam cores exhibiting generic non-linear compressive behaviours. Closed-form analytical solutions of the indentation curve are obtained for simplified foam compression behaviours: elastic-perfectly-plastic, bilinear and bilinear-perfectly-plastic. Analytical predictions are compared with experimental data from sandwiches employing foam cores with peculiar non-linear behaviours. The proposed models are found to give a better match of the e…

Evaluation of hand-arm vibrations during the use of portable olives harvesters

2013

The use of portable shakers in olives harvesting is becoming increasingly, especially in Sicily, both to reduce the costs of production and to assure the oil quality. Nevertheless, it’s well known that the use of such tools may involve risk of exposure to hand-transmitted vibration. Such exposure to vibrations is a potential cause of muscular/skeletal pains in hand–arm system, and specific pathologies such as Vibration-Induced White Finger (VWF) and Carpal Tunnel Syndrome (CTS), Hand–Arm Vibration Syndrome (HAVS). The aim of this study was to assess the level of exposure to hand-arm vibration of the operators during the use of portable shakers for olives harvesting. Two different commonly u…

Verso la nuova olivicoltura: modelli d'impianto, cultivar e tecniche colturali

Hybrid electric vehicle powertrain design: Construction of topologies and initial design schemes

2018

This paper introduces the generic representation and construction methods for the architectures of the four-wheel-drive hybrid electric vehicle (HEV) powertrain, which achieve the unified rules to represent and construct all types of HEV powertrains. To map the architecture into numerical variables and add it into optimization, the kinematic matrix of the HEV powertrain is extracted corresponding to the topological structure. Based on the torque distribution requirement of four-wheel-drive HEV, the initial design schemes (architecture and parameters) are created by charge-under-go feasibility inspection.

First tests of mechanical harvest of Origanum vulgare L.

2003

In Italy Origanum vulgare L. is cultivated only in few areas and its production does not even satisfy the national market demand. Until now the interest on this crop has been very low because of the high cost of manual harvest and bunch binding. The aim of this work is to evaluate the use of a reaper-binder (made for harvesting cereal crops) for harvesting and bunch binding Origanum vulgare L. The tests were carried out in Sicily, in the summer of 2001. The mechanical harvest was carried out using the reaper-binder unmodified, but the results were not satisfactory. The machine was then modified reducing its forward speed and cutting height, in order to improve its working productivity and h…

Italian Potential Biogas and Biomethane Production from OFMSW

2015

This work is aimed at predicting the potential biogas and biomethane production, using the Organic Fraction of Municipal Solid Waste (OFMSW), in Italy, where 1388 Anaerobic Digestion (AD) plants (power of 7.4 TWh, equal to 640.4 ktep) are nowadays available. In order to compute the potential biogas and biomethane production in the 20 Italian regions, the data about OFMSW production in 2010-2013 period have been evaluated. The Italian production of OFMSW, that was 5.2 million tons in 2013 (18% of MSW), could be used inside bioreactors for producing biogas and digestate, that must be aerobically composted into a biofertiliser. In 2013, the Italian potential biogas production from OFMSW was 73…