437 research outputs found

    MANIFESTA√á√ēES PATOL√ďGICAS EM ESTRUTURAS DE A√áOS: ESTUDO DE CASO DA FEIRA DA 304 SUL EM PALMAS/TO

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    Este artigo tem por finalidade o estudo das manifesta√ß√Ķes patol√≥gicas em estrutura met√°lica, procurando identific√°-las e indicar suas poss√≠veis causas e solu√ß√Ķes. Como objeto de estudo tem-se a edifica√ß√£o de uma feira de alimentos, localizada na quadra da 304 Sul na cidade de Palmas no estado do Tocantins. A estrutura da edifica√ß√£o √© toda em material met√°lico, possuindo o local grande import√Ęncia tur√≠stica e econ√īmica para a cidade de Palmas, em raz√£o¬† da vasta variadade de alimentos locias e regionais. Al√©m disso, fornece meios de divulga√ß√£o de forma direta aos pequenos produtores, gerando assim renda para as fam√≠lias desses e circula√ß√£o de capital. Ao tratarmos de patologias, estamos¬† referindo-se a "doen√ßa", falhas no sistema estrutural de uma edifica√ß√£o, em virtudes de varias a√ß√Ķes decorridas. Na edifica√ß√£o foram identificadas regi√Ķes cujos elementos estruturais em a√ßo foram danificados com processo de corros√£o, sem no entanto, comprometer a capacidade resistente. Para a resolu√ß√£o destes defeitos √© necess√°rio a remo√ß√£o do produto oriundo da corros√£o e recupera√ß√£o da pintura, garantindo maior est√©tica e vida √ļtil para a estrutura

    An√°lise Preliminar dos √ćndices de Instabilidade a Partir de Simula√ß√Ķes Realizadas com o Modelo Weather Research and Forecasting (WRF) para o Sul do Brasil

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    Este trabalho teve por objetivo avaliar a capacidade do modelo WRF em simular os √≠ndices de instabilidade em situa√ß√Ķes de tempestades durante primaveras com o fen√īmeno El Ni√Īo/Oscila√ß√£o Sul no Sul do Brasil em quatro cidades: Curitiba, Florian√≥polis, Foz do Igua√ßu e Porto Alegre. O modelo WRF foi utilizado para a realiza√ß√£o das simula√ß√Ķes, sendo que os valores dos √≠ndices K e TT foram simulados de forma satisfat√≥ria pelo WRF e razoavelmente para o LI. Os valores da CAPE simulados pelo WRF foi o que apresentaram as maiores diferen√ßas em rela√ß√£o √†s observa√ß√Ķes. Com rela√ß√£o ao comportamento dos √≠ndices K, TT e LI em rela√ß√£o √†s mensagens METAR, observou-se que os valores extremos simulados ocorreram muito pr√≥ximos aos registros de tempo inst√°vel nos aeroportos

    The second knee in the cosmic ray spectrum observed with the surface detector of the Pierre Auger Observatory

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    Event-by-event reconstruction of the shower maximum XmaxX_{\mathrm{max}} with the Surface Detector of the Pierre Auger Observatory using deep learning

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    A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality

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    The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ‚ąľ0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (Xmax_{max}) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of Xmax_{max} with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy

    Study on multi-ELVES in the Pierre Auger Observatory

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    Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 őľs (2013), to 300 őľs (2014-16), to 900 őľs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity
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