Search results for "Mechanics."
showing 10 items of 9274 documents
Simple flume with a central baffle
2016
Abstract In this paper the stage-discharge relationship of a flume with a central baffle is theoretically deduced using the Buckingham-Theorem of the dimensional analysis and the self-similarity theory. The new stage-discharge equation is calibrated by the measurements carried out by Peruginelli and Bonacci using a baffle having a given throat length and five different values of the contraction ratio. Finally, for a given throat length, a relationship linking the discharge with the upstream water depth, the contraction ratio and the contracted width is deduced.
Epigenetic regulation of sex differences in susceptibility to stress
2017
Under current diagnostics depression and stress related mood disorders have a higher occurrence in women than men. Little is known of the biological mechanisms contributing to these sex differences and how they may impact potential new therapeutics. Here we examine how DNA methylation contributes to sex specific stress vulnerability in adult animals. Mice of both sexes were exposed to variable stress and given a behavioral test battery to examine stress sensitivity. Female mice expressed depressionassociated behavior across all tests stress exposure whereas males were behaviorally resilient. Markers of pre and post-synaptic plasticity and spine morphology were examined using a combination o…
Fibre fragment distribution in a single-fibre composite tension test
2001
Abstract Single fibre fragmentation tests are performed for brittle fibres with Weibull strength distribution and different surface treatments. The fragmentation process is modelled and closed-form expressions for break spacing distribution are obtained. The model accounts for the effect of finite fibre length on the initial fragmentation as well as for break interaction on the advanced fragmentation stage. It is assumed that the exclusion zone due to fibre–matrix interface failure and stress recovery in the fibre is linearly dependent on the applied load. This assumption is validated experimentally. The derived theoretical average fragment length dependence on applied load is used to deter…
Time resolved emission at 1.3 μm of a single InAs quantum dot by using a tunable fibre Bragg grating
2013
Photoluminescence and time resolved photoluminescence from single metamorphic InAs/GaAs quantum dots (QDs) emitting at 1.3 mu m have been measured by means of a novel fibre-based characterization set-up. We demonstrate that the use of a wavelength tunable fibre Bragg grating filter increases the light collection efficiency by more than one order of magnitude as compared to a conventional grating monochromator. We identified single charged exciton and neutral biexciton transitions in the framework of a random population model. The QD recombination dynamics under pulsed excitation can be understood under the weak quantum confinement potential limit and the interaction between carriers at the …
Changes in biomechanics of skiing at maximal velocity caused by simulated 20 km skiing race using V2 skating technique
2018
This study investigated how the fatigue caused by a 20-km simulated skating cross-country skiing race on snow affects the final spurt performance from a biomechanical perspective. Subjects performed a 100-m maximal skiing trial before and at the end of the simulated race. Cycle characteristics, ground reaction forces from skis and poles, and muscle activity from eight muscles were recorded during each trial. Results showed that subjects were in a fatigued state after the simulated race manifested by 11.6% lower skiing speed (P<.01). The lower skiing speed was related to an 8.0% decrease in cycle rate (P<.01), whereas cycle length was slightly decreased (tendency). In temporal patterns, rela…
Dissimilar titanium-aluminum skin-stringer joints by FSW: process mechanics and performance
2022
Ever since its inception, friction stir welding (FSW) is being validated by scientific investigations as an effective substitution for fusion-based conventional joining technologies. One of the main strengths of FSW is the possibility to produce dissimilar joints, even using materials extremely different in terms of thermal and mechanical properties. The goal of the present research is to investigate the feasibility of both Al-Ti skin-stringer and reversed Ti-Al skin-stringer joints, highlighting the effect of joint configuration and main process parameters on material flow and joint mechanical properties. During the investigation, the essentiality of the proper heat input through balancing
Enhancing the Iterative Smoothed Particle Hydrodynamics Method
2021
Motivated by recent research on the iterative approach proposed for the smoothed particle hydrodynamics (ISPH) method, some ideas to improve the process are introduced. The standard procedure is enhanced iterating on the residuals preserving the matrix-free nature of the process. The method is appealing providing reasonable results with disordered data distribution too and no kernel variations are needed in the approximation. This work moves forward with a novel formulation requiring a lower number of iterations to reach a desired accuracy. The computational procedure is described and some results are introduced to appreciate the proposed formulation.
LA INCLUSIÓN DEL MÉDICO EN LA FORMACIÓN DEL INTÉRPRETE EN EL ÁMBITO SANITARIO
2017
La experiencia docente que describimos en este artículo propone la adquisición y desarrollo de destrezas interpretativas a través de cuatro sesiones teórico-prácticas sobre interpretación en los servicios públicos (ISP). Su particularidad reside en integrar a un profesional del ámbito médico-sanitario en el proceso de aprendizaje, que se perfecciona mediante role plays en el aula. Su colaboración desinteresada, activa y participativa estuvo presente desde la elección de los casos que se abordaron en clase derivados de sus experiencias con pacientes extranjeros, hasta la asunción del papel que habitualmente desempeñan en su trabajo en los ejercicios de simulación con los alumnos. La interacc…
Sonication-Induced Modification of Carbon Nanotubes: Effect on the Rheological and Thermo-Oxidative Behaviour of Polymer-Based Nanocomposites.
2018
The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT's original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behavio…
Etude numérique et expérimentale de l'assemblage acier aluminium par soudo-brasage
2006
Dans cet article nous étudions le soudo-brasage de tôles d'acier et d'aluminium (par la technique CMT, assemblage à clin). Ces métaux ont des coefficients de dilatation thermique différents, ce qui provoque des déformations, d'où des contraintes mécaniques élevées. Des expériences sur des éprouvettes, une simulation numérique thermomécanique sont menées en parallèle afin de mieux comprendre ces aspects thermiques et mécaniques dans le but de minimiser la déformation de l'assemblage.