Search results for "mechanical engineering"
showing 10 items of 4245 documents
Closed tank pneumatic press application to improve Sauvignon Blanc wine quality and nutraceutical properties
2019
The machines used in the winemaking process directly affect the quality of wine and its nutraceutical properties. Grapes-pressing is a very important step in winemaking as it may promote the presence and/or absence of enzymatic processes on the must, leading to the creation of different products in terms of chemical composition, starting from the same grapes. The aim of the study was to compare two different pressing systems of Sauvignon Blanc grapes using an innovative pneumatic discontinuous closed tank press in two operating modes: the traditional pressing mode in presence of oxygen and the inert pressing mode, performed through grapes pressing under inert gas with nitrogen recovery. Che…
Probabilistic Evaluation of the Adaptation Time for Structures under Seismic Loads
2016
Abstract In this paper, a probabilistic approach for the evaluation of the adaptation time for elastic perfectly plastic frames is proposed. The considered load history acting on the structure is defined as a suitable combination of quasi-statical loads and seismic actions. The proposed approach utilizes the Monte Carlo method in order to generate a suitable large number of seismic acceleration histories and for each one the related load combination is defined. Furthermore, for each load combination the related adaptation time is determined, if any, as the optimal one for which the structure is able to shakedown under the unamplified applied actions. A known generalized Ceradini's theorem i…
Validation of a Work Engagement Scale. Profi les associated with high Performance and Job Satisfaction
2017
El objetivo principal de este estudio consistía en la validación de una escala para la evaluación del work engagement -compromiso con el trabajo-, considerado como una presencia psicológica en el rol que incluye atención, absorción y energía dirigida a tareas laborales. Mediante análisis factorial confirmatorio, estimación de la consistencia interna y evidencias de validez convergente y discriminante, se confirma que la Escala Argentina de Compromiso con el Trabajo es una prueba válida y confiable para su uso en población argentina. Además, se buscó analizar si existen diferencias en los niveles de work engagement de acuerdo con variables individuales y organizacionales. Se observaron mayor…
Radial symmetry of p-harmonic minimizers
2017
"It is still not known if the radial cavitating minimizers obtained by Ball [J.M. Ball, Discontinuous equilibrium solutions and cavitation in nonlinear elasticity, Phil. Trans. R. Soc. Lond. A 306 (1982) 557--611] (and subsequently by many others) are global minimizers of any physically reasonable nonlinearly elastic energy". The quotation is from [J. Sivaloganathan and S. J. Spector, Necessary conditions for a minimum at a radial cavitating singularity in nonlinear elasticity, Ann. Inst. H. Poincare Anal. Non Lineaire 25 (2008), no. 1, 201--213] and seems to be still accurate. The model case of the $p$-harmonic energy is considered here. We prove that the planar radial minimizers are indee…
Cost that is Directly Incurred as a Result of Operating the Train Service on the 1520 mm Rail with Primarily Freight Transportation
2016
AbstractUnder the Directive 2012/34/EU (21 November 2012) “the charges for … [rail] infrastructure … shall be set at the cost that is directly incurred as a result of operating the train service”. This charging rule is new for Baltic States’ railways, where due to the favorable geographic position a full cost application without detalization was possible. Although, a big number of relevant studies on the issue was made in EU, all of them covered only 1435mm railways with primarily passenger transportation. This study has been made in order to understand the impact of train operating on 1520mm rail infrastructure with primarily freight transportation.A gradual model of infrastructure chargin…
Analysis of multiple intelligences and creativity in university students
2018
espanolResumen: Un reto de la educacion actual es formar a alumnos competentes para desenvolverse en una sociedad diversa y dinamica. El cociente intelectual no es suficiente para garantizar el exito academico ni profesional (Extremera & Fernandez-Berrocal, 2006) y deben considerarse aspectos cognitivos, sociales y emocionales. El objetivo del estudio fue analizar el grado alcanzado en estudiantes universitarios de trabajo social en las inteligencias multiples, inteligencia emocional, creatividad y rendimiento academico, asi como su relacion y las diferencias en funcion del sexo y el curso en una muestra de 100 estudiantes. Se encontraron diferencias significativas en funcion del curso y re…
Rocking behaviour of multi-block columns subjected to pulse-typeground motion accelerations
2016
Ancient columns, made with a variety of materials such as marble, granite, stone or masonry are an important part of theEuropean cultural heritage. In particular columns of ancient temples in Greece and Sicily which support only the architrave arecharacterized by small axial load values. This feature together with the slenderness typical of these structural members clearlyhighlights as the evaluation of the rocking behaviour is a key aspect of their safety assessment and maintenance. It has to be notedthat the rocking response of rectangular cross-sectional columns modelled as monolithic rigid elements, has been widely investigatedsince the first theoretical study carried out by Housner (19…
ESTIMATION ET CORRECTION DES ERREURS SYSTEMATIQUES D'UN SYSTEME DE MESURE 3D ASSOCIANT SCANNER NAPPE LASER ET MMT
2012
Les techniques de mesure sans contact par scanning laser permettent d'acquérir un grand nombre de points, à une cadence très rapide. Elles sont de plus en plus utilisées pour des applications industrielles telles que la rétro-conception, le contrôle de forme,... Toutefois, les incertitudes de mesures sont plus importantes que celles obtenues par les techniques classiques de mesure par contact. Nous proposons une procédure de correction des erreurs systématiques basée sur démarche expérimentale et qui concerne la mesure de pièces présentant une surface mate (peu de présence de bruit spéculaire). Les paramètres retenus dans la procédure sont les paramètres de positionnement du capteur par rap…
A Model for the Study of Sheath Currents in Medium Voltage Cables for Industrial Application
2020
In this paper, the implementation of a simulation model for studying the effect of cross-bonding of metallic sheaths and/or non-magnetic armor of single-core medium voltage cables in the same circuit is discussed. With the use of single-core cables, the resistive losses due to the induced circulating currents in cable sheaths or armors causes an increase of cable temperature that reduces its ampacity. In addition, the risk of electric shock due to induced voltages may be present if a person is exposed to the armor/sheath at the unbounded end. For this reason, special bonding techniques are used to significantly reduce these currents. The authors have implemented a model that could be used t…
ESTIMATING SOIL PARTICLE-SIZE DISTRIBUTION FOR SICILIAN SOILS
2009
The soil particle-size distribution (PSD) is commonly used for soil classification and for estimating soil behavior. An accurate mathematical representation of the PSD is required to estimate soil hydraulic properties and to compare texture measurements from different classification systems. The objective of this study was to evaluate the ability of the Haverkamp and Parlange (HP) and Fredlund et al. (F) PSD models to fit 243 measured PSDs from a wide range of 38 005_Bagarello(547)_33 18-11-2009 11:55 Pagina 38 soil textures in Sicily and to test the effect of the number of measured particle diameters on the fitting of the theoretical PSD. For each soil textural class, the best fitting perf…