The Effects of Small Group Exercise on Rate of Perceived Exertion and Mood State in College Students

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Piston Motion Performance Analysis of a 3DOF Electrothermal MEMS Scanner for Medical Applications.

International audienceMEMS scanners are useful for medical applications as optical coherence tomography, and laser microsurgery. Although widespread design of MEMS scanners have been presented, their behaviour is not well known and thus their motions are not easily and efficiently controlled. This lack induces several difficulties (limited resolution, accuracy, cycle time, etc.) and to tackle this problem, the paper presents the modeling of an ISCelectrothermally actuated MEMS mirror and the experimental characterization for the piston motion. Modeling and characterization are important to implement the control.A multiphysic model is proposed and an experimental validation is performed with a good correspondence for a voltage range from 0V to 3.5V with a maximum displacement up to 200_m and with a relative tilting difference of 0.1°. The paper also presents a simple and efficient experimental setup to measure a displacement in dynamic and static mode or a mirror plane tilting in static mode

Feasibility of Barley Straw Fibers as Reinforcement in Fully Biobased Polyethylene Composites: Macro and Micro Mechanics of the Flexural Strength

Awareness on deforestation, forest degradation, and its impact on biodiversity and global warming, is giving rise to the use of alternative fiber sources in replacement of wood feedstock for some applications such as composite materials and energy production. In this category, barley straw is an important agricultural crop, due to its abundance and availability. In the current investigation, the residue was submitted to thermomechanical process for fiber extraction and individualization. The high content of holocellulose combined with their relatively high aspect ratio inspires the potential use of these fibers as reinforcement in plastic composites. Therefore, fully biobased composites were fabricated using barley fibers and a biobased polyethylene (BioPE) as polymer matrix. BioPE is completely biobased and 100% recyclable. As for material performance, the flexural properties of the materials were studied. A good dispersion of the reinforcement inside the plastic was achieved contributing to the elevate increments in the flexural strength. At a 45 wt.% of reinforcement, an increment in the flexural strength of about 147% was attained. The mean contribution of the fibers to the flexural strength was assessed by means of a fiber flexural strength factor, reaching a value of 91.4. The micromechanical analysis allowed the prediction of the intrinsic flexural strength of the fibers, arriving up to around 700 MPa, and coupling factors between 0.18 and 0.19, which are in line with other natural fiber composites. Overall, the investigation brightness on the potential use of barley straw residues as reinforcement in fully biobased polymer composites

Phase structure and phase transitions of the SU(2) x O(N) symmetric scalar field theory

Radiatively induced SU(2) symmetry breaking is shown to be a genuine feature of SU(2) x O(N) globally symmetric renormalisable field theories in the large N limit, describing interaction of a complex SU(2) doublet, O(N)-singlet field with an SU(2) singlet, O(N) vector. Symmetry breaking solutions are found even when all fields have positive renormalised squared mass. The emerging novel mechanism of symmetry breaking can reproduce with a choice of N~300 the standard range of the electroweak condensate and the Higgs mass occurring in the extended Higgs dynamics of an SU(2) symmetric Gauge+Higgs model.Comment: 6 pages, 3 figures; the role of the cut-off in the effective theory is discussed, references added; to appear in Europhys. Let

Descripció del sistema dunar d’es Codolar (Eivissa, Illes Balears)

En el present treball es realitza una descripció geoambiental del sistema dunar d’es Codolar, Eivissa. Aquesta àrea està situada dins l’àrea de Parc Natural de ses Salines d’Eivissa i Formentera (Illes Balears). Aquest sistema platja-duna era desconegut i té la particularitat que es troba desvinculat de la seva font d’alimentació, constituint un veritable mant eòlic. La platja arenosa actualment està coberta per distintes barres de còdols i graves. El sistema dunar, separat de la platja, presenta elevats símptomes regressius, on es pot observar la fragmentació del sistema amb la presència de dos nuclis arenosos independents un de l’altre que en temps pretèrits eren tot un, d’extensió molt superior a l’actual. A més de la descripció geomorfològica també s’incorpora un inventari florístic i una breu discussió sobre les característiques de la vegetació

Naturalness bounds in extensions of the MSSM without a light Higgs boson

Adopting a bottom-up point of view, we make a comparative study of the simplest extensions of the MSSM with extra tree level contributions to the lightest Higgs boson mass. We show to what extent a relatively heavy Higgs boson, up to 200-350 GeV, can be compatible with data and naturalness. The price to pay is that the theory undergoes some change of regime at a relatively low scale. Bounds on these models come from electroweak precision tests and naturalness, which often requires the scale at which the soft terms are generated to be relatively low.Comment: 18 pages, 5 figures. v2: minor revision, added references. v3,v4: some numerical correction

When geography matters: International diversification and firm performance of spanish multinationals

Indexación: Scopus.This paper studies how the nature and shape of the relationship between inter-national diversification (ID) and performance (P) may vary according to a firm’s geographical focus of internationalization. Using a sample of Spanish multinational firms for the 2004—2012 period we find an M-shaped relationship. However, significant differences are found when the different geographical foci of internationalization are considered. Strong support is found when firms adopt a regional focus (an inverted S-curve when the ID measure refers to the number of foreign countries and an M-curve when it refers to the size of the network of foreign sub-sidiaries), a biregional focus (an S-curve) and a semiglobal focus (an inverted S-curve but also an M-curve with foreign subsidiaries). These findings and their pattern suggest the critical impor-tance of the country of origin and the geographical focus of internationalization in explaining the relationship between ID—P.https://journals.sagepub.com/doi/10.1177/234094442089898

Preliminary Design of Reactive Distillation Columns

A procedure that combines feasibility analysis, synthesis and design of reactive distillation columns is introduced. The main interest of this methodology lies on a progressive introduction of the process complexity. From minimal information concerning the physicochemical properties of the system, three steps lead to the design of the unit and the specification of its operating conditions. Most of the methodology exploits and enriches approaches found in the literature. Each step is described and our contribution is underlined. Its application is currently limited to equilibrium reactive systems where degree of freedom is equal to 2 or less than 2. This methodology which provides a reliable initialization point for the optimization of the process has been applied with success to different synthesis. The production of methyl-tert-butyl-ether (MTBE) and methyl acetate are presented as examples