Search results for " meccanica"
showing 10 items of 819 documents
Valutazione di sistemi GPS e DGPS combinati con metodi di correzione e sistemi non satellitari
2000
The aim of this work is assess the accuracy of three positiotining systems: a hand-held GPS receiver, tested on itself and together with a pseudo-differential method; a DGPS system; a dead reckoning system. Test results suggest that, for row crops, the "corrected" GPS, the DGPS and the dead reckoning systems satisfy the accuracy requirement for mapping in post-processing soil and crop parameters. It is possible to improve the reliability of position resolution, by using a combined DGPS-dead reckoning system that overcomes the problems of signal weakening and obstruction.
Current state and future of biogas and digestate production
2013
Over the past few years, the worldwide cost of energy has increased significantly, due to a growing global demand for energy and the decreasing availability of fossil fuel sources. Many countries are adopting environmental policies promoting the production and consumption of alternative, sustainable and renewable energy sources. Among these sources is green energy production through the anaerobic digestion of agricultural feedstock, like animal manure and food industry by-products, mainly aimed at producing biogas. Nevertheless, only a very small part of the biogas potential is currently used, while many European countries are facing huge problems caused by the overproduction of organic was…
Design, Manufacturing, and Strength Test of a 4-post ROPS Fitted on a Very Low-Profile Tractor (TRACLAS Project)
2022
To improve the safety level when agricultural tractors work on slope under canopy, INAIL (the Italian National Institute for Insurance against Accidents at Work) funded a research project, named TRACLAS, devoted to set-up a prototype of low-profile compact tractor, not exceeding 1.60 m overall height, equipped with a 4-post ROPS (RollOver Protective Structure). After the complete set-up of the prototype, some field and lab tests were carried out to compare its performance with those of some comparable tractor models already on the market, used in vineyards, orchards and greenhouses. A basic step of the TRACLAS project was the execution of the strength test of the customized 4-post frame (th…
AN EXTENDED KALMAN FILTER BASED TECHNIQUE FOR ON-LINE IDENTIFICATION OF UAS PARAMETERS.
2015
The present article deals with the identification,at the same time, of aircraft stability and control parameters taking into account dynamic damping derivatives. Such derivatives,due to the rate of change of the angle of attack, are usually neglected. So the damping characteristics of aircraft dynamics are attributed only on pitch rate derivatives. To cope with the dynamic effects of these derivatives, authors developed devoted procedures to estimate them. In the present paper, a complete model of aerodynamic coefficients has been tuned-up to identify simultaneously the whole set of derivatives. Besides, in spite of the employed reduced order model and/or decoupled dynamics, a six degrees o…
Influence of Joint Geometry on Micro and Macro Mechanical Properties of Friction Stir Spot Welded Joints
2014
AbstractSpot welding can be considered a very common joining technique in automotive and transportation industries as it permits to obtain effective lap-joints with short process times and what is more it is easily developed through robots and automated systems. Recently, Friction Stir Spot Welding (FSSW) has been proposed as a natural evolution of the already known Friction Stir Welding (FSW) process, allowing to obtain sound spot joints that do not suffer from the insurgence of typical welding defects due to the melting of the base material. Similarly to FSW, both geometrical and technological parameters must be considered as they affect the material flow and the heat flux generated durin…
Predicting Outcome of Aortic Dissection with Patent False Lumen by Computational Flow Analysis
2014
Although Type B aortic dissection (AoD) has better in-hospital survival than Type A AoD, the short- and long term outcome for patients remains challenging, with 50–80% deaths at 5-years. Dissection-related complications include rapid aortic expansion, impending rupture, and malperfusion syndromes. We aimed to assess hemodynamic implications of patients with patent false lumen (FL) of dissected aorta. Computational fluid dynamic analyses were performed on patient-specific aortic geometries reconstructed from computed tomography scans of 25 patients with AoDs, who were admitted in our hospital from 2007 to 2013. We used the development of acute complications and chronic aneurysmal evolution a…
Constitutive modeling of ascending thoracic aortic aneurysms using microstructural parameters.
2016
Ascending thoracic aortic aneurysm (ATAA) has been associated with diminished biomechanical strength and disruption in the collagen fiber microarchitecture. Additionally, the congenital bicuspid aortic valve (BAV) leads to a distinct extracellular matrix structure that may be related to ATAA development at an earlier age than degenerative aneurysms arising in patients with the morphological normal tricuspid aortic valve (TAV). The purpose of this study was to model the fiber-reinforced mechanical response of ATAA specimens from patients with either BAV or TAV. This was achieved by combining image-analysis derived parameters of collagen fiber dispersion and alignment with tensile testing dat…
Swerve correction of heavy-duty articulated lorries
2016
The trailers of heavy-duty articulated lorries are usually linked to the tractors by auxiliary dollies to improve the manoeuvrability along curved paths. Connecting the dolly to the tractor by a four-bar linkage, some performance improvement may be achieved in comparison with the conventional single pin. The correct path along a road curve may be obtained exerting control moments on the horizontal plane by means of differential braking of the wheels. The results of the analysis show that the forward-converging and the crossing bar quadrilaterals are mostly yaw-stable, whereas the farther backward-converging bars prove to be inherently unstable.
Gain scheduling automatic landing system by modeling Ground Effect
2014
Taking ground effect into account a longitudinal automatic landing system is designed. Such a system will be tested and implemented on board by using the Preceptor N3 Ultrapup aircraft which is used as technological demonstrator of new control navigation and guidance algorithms in the context of the “Research Project of National Interest” (PRIN 2008) by the Universities of Bologna, Palermo, Ferrara and the Second University of Naples. A general mathematical model of the studied aircraft has been built to obtain non–linear analytical equations for aerodynamic coefficients both Out of Ground Effect and In Ground Effect. To cope with the strong variations of aerodynamic coefficients In Ground …
Low cost three-dimensional virtual model construction for remanufacturing industry
2018
Remanufactured products can save up to 80% of production and energy costs whilst generating lower CO2 emissions. The key success factors for remanufacturing are quality, lead-time and cost. Extensive work within the industry and the detailed analysis of the remanufacturing process has shown that component inspection has significant bearing on overall productivity. Remanufacturing lacks automation because activities are predominantly manual. Automation of remanufacturing process will not only decrease the number of non-remanufacturable components, through decreasing cost and increasing consistency in quality, but also attract industries to design for remanufacture. A digital model of the com…