Search results for " MEC"
showing 10 items of 8161 documents
A Note on the Mechanics of Ancient Gear Systems
2011
This paper deals with the mechanical behavior of the gearwheels of the antiquity, which were generally characterized by triangular shaping of the teeth. The engagement of the conjugate profiles is analyzed in detail, calculating the temporal variation of the speed ratio due to the back and forth shifting of the relative instant center. The admissibility of the points of the theoretical contact path is carefully checked, estimating also the magnitude of the successive tooth collisions and ascertaining the energy losses arising from the particular nature of the coupling. Some very interesting results are that only one couple of teeth turns out to be active at each time instant and that the re…
A Novel Pathophysiological Mechanism Contributing to Trigeminal Neuralgia
2016
Trigeminal neuralgia (TN) is a form of neuropathic pain that affects the fifth cranial nerve, the most widely distributed nerve in the head. Although TN has been associated with a variety of pathological conditions, neurovascular compression on the trigeminal nerve, as it exits the brain stem, is the most frequent reported cause. This compression provides a progressive demyelination of the nerve and a subsequent aberrant neural transmission. Although several studies have clarified some physiopathological mechanisms underlying TN, the molecular basis remains vague. Very recently the substitution of methionine 136 by valine (MET126Val) in sodium channel Nav1.6 in a case study of typical TN ha…
Evaluación y caracterización biomecánica de los trinquetes de pelota valenciana. (Biomechanical assessment and characterization of the Valencian ball…
2012
El trinquete es la instalacion de referencia en la practica de la pelota valenciana, donde se juegan las modalidades profesionales de escala i corda y raspall. Sin embargo, no existe una normativa ni procedimientos de ensayo especificos que permitan definir las caracteristicas mecanicas que deben reunir paredes y pavimento del trinquete, para que los jugadores tengan una practica segura y optimicen su rendimiento. El objetivo de este estudio fue analizar diferentes variables mecanicas en las instalaciones de juego, determinar los procedimientos de ensayo mas adecuados y, finalmente, proponer unos valores mecanicos que definan una instalacion de calidad. Los estudios se llevaron a cabo en 10…
Design, fabrication and evaluation of an online Intelligent machine for trout beheading and gutting
2021
La clasificación y procesado de pescado empleando máquinas automáticas reduce costes e incrementa el volumen de procesado. Después de su llegada a los mercados de distribución mayorista y minorista, el tamaño de los ejemplares suele ser muy variado para la mayoría de las especies (trucha, caballa, dorada, lubina, etc.). Debido a ello, la limpieza y corte de pescado se realiza habitualmente de forma manual. Este proceso involucra diferentes pasos y a menudo se corta en función de la demanda del usuario: sin cabeza, sin vísceras, sin cabeza ni vísceras, fileteado, etc. Combinando diferentes elementos tecnológicos, hoy en día es posible el desarrollo de sistemas automáticos capaces de mejorar …
Electronic Energy Meter Based on a Tunnel Magnetoresistive Effect (TMR) Current Sensor
2017
In the present work, the design and microfabrication of a tunneling magnetoresistance (TMR) electrical current sensor is presented. After its physical and electrical characterization, a wattmeter is developed to determine the active power delivered to a load from the AC 50/60 Hz mains line. Experimental results are shown up to 1000 W of power load. A relative uncertainty of less than 1.5% with resistive load and less than 1% with capacitive load was obtained. The described application is an example of how TMR sensing technology can play a relevant role in the management and control of electrical energy.
Tuteliamo il territorio: giornata del bio al Castello Chiaramontano di Racalmuto
2014
convegno sul territorio
Milano, successo per TuttoFood
2013
Milano, successo per TuttoFood
Strictly correlated electrons approach to excitation energies of dissociating molecules
2019
In this work we consider a numerically solvable model of a two-electron diatomic molecule to study a recently proposed approximation based on the density functional theory of so-called strictly correlated electrons (SCE). We map out the full two-particle wave function for a wide range of bond distances and interaction strengths and obtain analytic results for the two-particle states and eigenenergies in various limits of strong and weak interactions, and in the limit of large bond distance. We then study the so-called Hartree-exchange-correlation (Hxc) kernel of time-dependent density functional theory which is a key ingredient in calculating excitation energies. We study an approximation b…
Prompt Determination of the Mechanical Properties of Industrial Polypropylene Sandwich Pipes
2021
A simple and prompt method to determine the mechanical properties of industrial multilayer extrusion polypropylene pipes for a gravity sewer network is suggested. The engineering formulas included for calculating the permissible thickness and relative position of a foam core in the pipes are based on a linear-elastic approximation and the rule of mixtures. The applicability of the approximation was justified experimentally during investigation of the effective tensile characteristics of single- and multilayer pipes and each layer specimen by using traditional tests and finite-element calculations. The results obtained were used to formulate engineering recommendations for calculations of th…
Hydro-mechanical modelling of a natural slope affected by a multiple slip surface failure mechanism
2009
A coupled hydro-mechanical formulation is presented for the analysis of landslide motion during crisis episodes. The mathematical formulation is used to model a natural slope affected by a multiple slip surface failure mechanism, in which pore water pressure evolution was identified as the main cause for movement accelerations. An elasto-plastic constitutive model is adopted for the behaviour of slip surfaces. Material parameters are obtained by combining the available laboratory tests and the back analysis of some crisis episodes. After being calibrated and validated, the model is applied to improve the understanding of the physical processes involved and to predict the landslide behaviour…