1,869 research outputs found

    Snap evaporation of droplets on smooth topographies

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    Droplet evaporation on solid surfaces is important in many applications including printing, micro-patterning and cooling. While seemingly simple, the configuration of evaporating droplets on solids is difficult to predict and control. This is because evaporation typically proceeds as a “stick-slip” sequence—a combination of pinning and de-pinning events dominated by static friction or “pinning”, caused by microscopic surface roughness. Here we show how smooth, pinning-free, solid surfaces of non-planar topography promote a different process called snap evaporation. During snap evaporation a droplet follows a reproducible sequence of configurations, consisting of a quasi-static phase-change controlled by mass diffusion interrupted by out-of-equilibrium snaps. Snaps are triggered by bifurcations of the equilibrium droplet shape mediated by the underlying non-planar solid. Because the evolution of droplets during snap evaporation is controlled by a smooth topography, and not by surface roughness, our ideas can inspire programmable surfaces that manage liquids in heat- and mass-transfer applications

    Situational judgment tests as measures of 21st century skills: Evidence across Europe and Latin America

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    Over the years, various governmental, employment, and academic organizations have identified a list of skills to successfully master the challenges of the 21st century. So far, an adequate assessment of these skills across countries has remained challenging. Limitations inherent in the use of self-reports (e.g., lack of self-insight, socially desirable responding, response style bias, reference group bias, etc.) have spurred on the search for methods that could complement or even substitute self-report inventories. Situational judgment tests (SJTs) have been proposed as one of the complements/alternatives to the traditional self-report inventories. SJTs are low-fidelity simulations that confront participants with multiple domain-relevant situations and request to choose from a set of predefined responses. Our objectives are twofold: (a) outlining how a combined emic-etic approach can be used for developing SJT items that can be used across geographical regions and (b) investigating whether SJT scores can be compared across regions. Our data come from Laureate International Universities (N = 5,790) and comprise test-takers from Europe and Latin America who completed five different SJTs that were developed in line with a combined emic-etic approach. Results showed evidence for metric measurement invariance across participants from Europe and Latin America for all five SJTs. Implications for the use of SJTs as measures of 21st century skills are discussed

    Identification of multiple root disease resistant wheat germplasm against cereal nematodes and dryland root rot and their validation in regions of economic importance

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    HistĂłria da literatura portuguesa coordenada por Giulia Lanciani - primeiras pĂĄginas de um total pp. 7-108)HistĂłria literĂĄria do sĂ©culo XVIII portuguĂȘsGoverno de Portuga

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+→Ό+ÎœW^+ \rightarrow \mu^+\nu and W−→Ό−ΜW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector