1,218 research outputs found

    Two-scale convergence for locally-periodic microstructures and homogenization of plywood structures

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    The introduced notion of locally-periodic two-scale convergence allows to average a wider range of microstructures, compared to the periodic one. The compactness theorem for the locally-periodic two-scale convergence and the characterisation of the limit for a sequence bounded in H1(Ω)H^1(\Omega) are proven. The underlying analysis comprises the approximation of functions, which periodicity with respect to the fast variable depends on the slow variable, by locally-periodic functions, periodic in subdomains smaller than the considered domain, but larger than the size of microscopic structures. The developed theory is applied to derive macroscopic equations for a linear elasticity problem defined in domains with plywood structures.Comment: 22 pages, 4 figure

    A Fabry-Perot interferometer with quantum mirrors: nonlinear light transport and rectification

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    Optical transport represents a natural route towards fast communications, and it is currently used in large scale data transfer. The progressive miniaturization of devices for information processing calls for the microscopic tailoring of light transport and confinement at length scales appropriate for the upcoming technologies. With this goal in mind, we present a theoretical analysis of a one-dimensional Fabry-Perot interferometer built with two highly saturable nonlinear mirrors: a pair of two-level systems. Our approach captures non-linear and non-reciprocal effects of light transport that were not reported previously. Remarkably, we show that such an elementary device can operate as a microscopic integrated optical rectifier

    Locally periodic unfolding method and two-scale convergence on surfaces of locally periodic microstructures

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    In this paper we generalize the periodic unfolding method and the notion of two-scale convergence on surfaces of periodic microstructures to locally periodic situations. The methods that we introduce allow us to consider a wide range of non-periodic microstructures, especially to derive macroscopic equations for problems posed in domains with perforations distributed non-periodically. Using the methods of locally periodic two-scale convergence (l-t-s) on oscillating surfaces and the locally periodic (l-p) boundary unfolding operator, we are able to analyze differential equations defined on boundaries of non-periodic microstructures and consider non-homogeneous Neumann conditions on the boundaries of perforations, distributed non-periodically

    Investigations of fast neutron production by 190 GeV/c muon interactions on different targets

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    The production of fast neutrons (1 MeV - 1 GeV) in high energy muon-nucleus interactions is poorly understood, yet it is fundamental to the understanding of the background in many underground experiments. The aim of the present experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c muons scattering on carbon, copper and lead targets. We have investigated the energy spectrum and angular distribution of spallation neutrons, and we report the result of our measurement of the neutron production differential cross section.Comment: 19 pages, 11 figures ep

    Allergic contact dermatitis to shoes induced by dimethylfumarate: A new allergen imported from China

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    BACKGROUND: In the last two years several cases of severe contact dermatitis related to newly acquired sofas and armchairs originating from China have been published. The responsible allergen is dimethylfumarate (DMF), an extremely potent sensitizer and irritant found in sachets inside the furniture. Recently, cases of contact dermatitis related to shoes and riding helmets have also been described. METHODS: We evaluated two patients with allergic contact dermatitis related to shoes manufactured in China that were contaminated by dimethylfumarate found in sachets placed inside the shoeboxes. RESULTS: Patch tests with DMF extracted from the sachets inside the shoeboxes showed positive reactions. Postitive reactions were also obtained using small fragments of the shoes and tissue of the "MouldProof" sachet. The patients were instructed to avoid the suspected shoes and were treated with topical corticosteroids. CONCLUSIONS: Contact dermatitis induced by dimethylfumarate should be suspected in appropriate cases. It is important to remember that this allergen is not included in most series for patch testing

    Towards more humane machines: creating emotional social robots

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    Robots are now widely used in industrial settings, and today the world has woken up to the impact that they will have in our society. But robots have been limited to repetitive, industrial tasks. However, recent platforms are becoming more secure to operate amongst humans, and research in Human-Robot Interaction (HRI) is preparing robots for use in schools, public services and eventually everyone’s home. If we aim for a robot flexible enough to work around humans and decide autonomously how to act in complex situations, a notion of morality is needed for their decision making. In this chapter we argue that we can achieve some level of moral decision making in social robots if they are endowed with empathy capabilities. We then discuss how to build artificial empathy in robots, giving some concrete examples of how these implementations can guide the path to creating moral social robots in the future.info:eu-repo/semantics/acceptedVersio

    Cam deformity and the omega angle, a novel quantitative measurement of femoral head-neck morphology: a 3D CT gender analysis in asymptomatic subjects

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    OBJECTIVE: Our objectives were to use 3D computed tomography (CT) to define head-neck morphologic gender-specific and normative parameters in asymptomatic individuals and use the omega angle (Ω°) to provide quantification data on the location and radial extension of a cam deformity. METHODS: We prospectively included 350 individuals and evaluated 188 asymptomatic hips that underwent semiautomated CT analysis. Different thresholds of alpha angle (α°) were considered in order to analyze cam morphology and determine Ω°. We calculated overall and gender-specific parameters for imaging signs of cam morphology (Ω° and circumferential α°). RESULTS: The 95 % reference interval limits were beyond abnormal thresholds found in the literature for cam morphology. Specifically, α° at 3/1 o´clock were 46.9°/60.8° overall, 51.8°/65.4° for men and 45.7°/55.3° for women. Cam prevalence, magnitude, location, and epicenter were significantly gender different. Increasing α° correlated with higher Ω°, meaning that higher angles correspond to larger cam deformities. CONCLUSION: Hip morphometry measurements in this cohort of asymptomatic individuals extended beyond current thresholds used for the clinical diagnosis of cam deformity, and α° was found to vary both by gender and measurement location. These results suggest that α° measurement is insufficient for the diagnosis of cam deformity. Enhanced morphometric evaluation, including 3D imaging and Ω°, may enable a more accurate diagnosis. KEY POINTS: • 95% reference interval limits of cam morphotype were beyond currently defined thresholds. • Current morphometric definitions for cam-type morphotype should be applied with care. • Cam prevalence, magnitude, location, and epicenter are significantly gender different. • Cam and alpha angle thresholds should be defined according to sex/location. • Quantitative 3D morphometric assessment allows thorough and reproducible FAI diagnosis and monitoring.info:eu-repo/semantics/publishedVersio
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