Browsing by Issue Date, starting with "2017-11-10"
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- Preparação e programação de manutenção industrial na empresa Celbi, S. A.Publication . Cabete, Samuel Figueiredo; Santos, Victor Daniel Neto dosO presente documento apresenta as tarefas realizadas no âmbito da componente de Estágio/Projeto/Dissertação, do Mestrado em Engenharia Eletrotécnica (MEE), ramo Automação e Comunicações em Sistemas Industriais, leccionada no Departamento de Engenharia Eletrotécnica (DEE), do Instituto Superior de Engenharia de Coimbra (ISEC). O referido estágio foi realizado na empresa Celulose Beira Industrial - Celbi S. A., sediada na localidade de Leirosa, Figueira da Foz. O trabalho realizado compreendeu o estudo e aplicação de diversas metodologias de manutenção em contexto laboral, designadamente no sector da produção de pasta de papel. Neste relatório de estágio é efectuado, primeiramente, o estudo do estado da arte da Manutenção na indústria, apresentando-se os benefícios que daí advêm, sempre numa perspectiva de melhoria contínua da eficiência das empresas. De seguida, descrevem-se as atividades desenvolvidas ao longo do estágio, na óptica do preparador de trabalhos de manutenção, salientando-se as metodologias e políticas adotadas pela empresa, a sua cultura de manutenção, bem como a evolução das mesmas ao longo dos anos.
- Search for black holes in high-multiplicity final states in proton-proton collisions at $ \sqrt{s}=$13 TeVPublication . CMS collaboration (2228 authors); Nayak, Aruna; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Calpas, Betty; Di Francesco, Agostino; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Hollar, Jonathan; Leonardo, Nuno; Lloret Iglesias, Lara; Rodrigues Antunes, Joao; Seixas, Joao; Toldaiev, Oleksii; Vadruccio, Daniele; Varela, Joao; Vischia, Pietro; David Tinoco Mendes, Andre; Silva, Pedro; Musella, Pasquale; Pela, JoaoA search for new physics in energetic, high-multiplicity final states has been performed using proton–proton collision data collected with the CMS detector at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 2.3 fb−1 . The standard model background, dominated by multijet production, is determined exclusively from control regions in data. No statistically significant excess of events is observed. Model-independent limits on the product of the cross section and the acceptance of a new physics signal in these final states are set and further interpreted in terms of limits on the production of black holes. Semiclassical black holes and string balls with masses as high as 9.5 TeV , and quantum black holes with masses as high as 9.0 TeV are excluded by this search in the context of models with extra dimensions, thus significantly extending limits set at a center-of-mass energy of 8 TeV with the LHC Run 1 data.
- Measurement of $b$-hadron pair production with the ATLAS detector in proton-proton collisions at $\sqrt{s}=8$ TeVPublication . ATLAS collaboration (2863 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oleiro Seabra, Luis Filipe; Onofre, António; Pedro, Rute; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutA measurement of b-hadron pair production is presented, based on a data set corresponding to an integrated luminosity of 11.4 fb$^{−1}$ of proton-proton collisions recorded at $ \sqrt{s}=8 $ TeV with the ATLAS detector at the LHC. Events are selected in which a b-hadron is reconstructed in a decay channel containing J/ψ → μμ, and a second b-hadron is reconstructed in a decay channel containing a muon. Results are presented in a fiducial volume defined by kinematic requirements on three muons based on those used in the analysis. The fiducial cross section is measured to be 17.7 ± 0.1(stat.) ± 2.0(syst.) nb. A number of normalised differential cross sections are also measured, and compared to predictions from the Pythia8, Herwig++, MadGraph5_aMC@NLO+Pythia8 and Sherpa event generators, providing new constraints on heavy flavour production.
- Measurement of jet $p_{\mathrm{T}}$ correlations in Pb+Pb and $pp$ collisions at $\sqrt{s_{\mathrm{NN}}}=$ 2.76 TeV with the ATLAS detectorPublication . ATLAS collaboration (2831 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oleiro Seabra, Luis Filipe; Onofre, António; Pedro, Rute; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutMeasurements of dijet pT correlations in Pb+Pb and pp collisions at a nucleon–nucleon centre-of-mass energy of sNN=2.76 TeV are presented. The measurements are performed with the ATLAS detector at the Large Hadron Collider using Pb+Pb and pp data samples corresponding to integrated luminosities of 0.14 nb−1 and 4.0 pb−1 , respectively. Jets are reconstructed using the anti- kt algorithm with radius parameter values R=0.3 and R=0.4 . A background subtraction procedure is applied to correct the jets for the large underlying event present in Pb+Pb collisions. The leading and sub-leading jet transverse momenta are denoted pT1 and pT2 . An unfolding procedure is applied to the two-dimensional ( pT1,pT2 ) distributions to account for experimental effects in the measurement of both jets. Distributions of (1/N)dN/dxJ , where xJ=pT2/pT1 , are presented as a function of pT1 and collision centrality. The distributions are found to be similar in peripheral Pb+Pb collisions and pp collisions, but highly modified in central Pb+Pb collisions. Similar features are present in both the R=0.3 and R=0.4 results, indicating that the effects of the underlying event are properly accounted for in the measurement. The results are qualitatively consistent with expectations from partonic energy loss models.
- Combination of searches for heavy resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton–proton collisions at $\sqrt{s}=8$ and 13 TeVPublication . CMS collaboration (2190 authors); Nayak, Aruna; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Calpas, Betty; Di Francesco, Agostino; Faccioli, Pietro; Gallinaro, Michele; Hollar, Jonathan; Leonardo, Nuno; Lloret Iglesias, Lara; Seixas, Joao; Toldaiev, Oleksii; Vadruccio, Daniele; Varela, Joao; Vischia, Pietro; David Tinoco Mendes, Andre; Silva, Pedro; Musella, Pasquale; Pela, JoaoA statistical combination of searches is presented for massive resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton–proton collision data collected by the CMS experiment at the LHC. The data were taken at centre-of-mass energies of 8 and 13 TeV, corresponding to respective integrated luminosities of 19.7 and up to 2.7 fb −1 . The results are interpreted in the context of heavy vector triplet and singlet models that mimic properties of composite-Higgs models predicting W′ and Z′ bosons decaying to WZ, WW, WH, and ZH bosons. A model with a bulk graviton that decays into WW and ZZ is also considered. This is the first combined search for WW, WZ, WH, and ZH resonances and yields lower limits on masses at 95% confidence level for W′ and Z′ singlets at 2.3 TeV, and for a triplet at 2.4 TeV. The limits on the production cross section of a narrow bulk graviton resonance with the curvature scale of the warped extra dimension k˜=0.5 , in the mass range of 0.6 to 4.0 TeV, are the most stringent published to date.
- Measurement of vector boson scattering and constraints on anomalous quartic couplings from events with four leptons and two jets in proton–proton collisions at $\sqrt{s}=$ 13 TeVPublication . CMS collaboration (2237 authors); Nayak, Aruna; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Di Francesco, Agostino; Faccioli, Pietro; Galinhas, Bruno; Gallinaro, Michele; Hollar, Jonathan; Leonardo, Nuno; Lloret Iglesias, Lara; Seixas, Joao; Strong, Giles; Toldaiev, Oleksii; Vadruccio, Daniele; Varela, Joao; Vischia, Pietro; David Tinoco Mendes, Andre; Silva, Pedro; Musella, PasqualeA measurement of vector boson scattering and constraints on anomalous quartic gauge couplings from events with two Z bosons and two jets are presented. The analysis is based on a data sample of proton–proton collisions at s=13 TeV collected with the CMS detector and corresponding to an integrated luminosity of 35.9 fb−1 . The search is performed in the fully leptonic final state ZZ→ℓℓℓ′ℓ′ , where ℓ,ℓ′=e or μ . The electroweak production of two Z bosons in association with two jets is measured with an observed (expected) significance of 2.7 (1.6) standard deviations. A fiducial cross section for the electroweak production is measured to be σEW(pp→ZZjj→ℓℓℓ′ℓ′jj)=0.40−0.16+0.21(stat)−0.09+0.13(syst) fb , which is consistent with the standard model prediction. Limits on anomalous quartic gauge couplings are determined in terms of the effective field theory operators T0, T1, T2, T8, and T9. This is the first measurement of vector boson scattering in the ZZ channel at the LHC.
- Search for heavy resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the $q\bar{q}^{(\prime)}b\bar{b}$ final state in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detectorPublication . ATLAS collaboration (2874 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oleiro Seabra, Luis Filipe; Onofre, António; Pedro, Rute; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutA search for heavy resonances decaying to a W or Z boson and a Higgs boson in the qq¯(′)bb¯ final state is described. The search uses 36.1 fb−1 of proton–proton collision data at s=13 TeV collected by the ATLAS detector at the CERN Large Hadron Collider in 2015 and 2016. The data are in agreement with the Standard Model expectations, with the largest excess found at a resonance mass of 3.0 TeV with a local (global) significance of 3.3 (2.1) σ . The results are presented in terms of constraints on a simplified model with a heavy vector triplet. Upper limits are set on the production cross-section times branching ratio for resonances decaying to a W ( Z ) boson and a Higgs boson, itself decaying to bb¯ , in the mass range between 1.1 and 3.8 TeV at 95% confidence level; the limits range between 83 and 1.6 fb (77 and 1.1 fb) at 95% confidence level.