Navegação Ciências Exatas e da Terra por Título

Resultados 3443-3462 de 5964

    • Nature of insoluble material found in the bottom of soybean biodiesel storage tank : chemical and microbiological approach 

      Cazarolli, Juciana Clarice; Boelter, Gabriela; Lima, Amanda Muliterno Domingues Lourenço de; Hengles, Thaisa Concha Vasquez; Correa, Camila; Peralba, Maria do Carmo Ruaro; Ferrão, Marco Flôres; Cavalcanti, Eduardo Homem de Siqueira; Bisol, Márcia Veroneze; Bezerra, Kelly da Silva; Antoniosi Filho, Nelson Roberto; Bento, Fatima Menezes (2018) [Artigo de periódico]
      During biodiesel storage, chemical reactions may occur, producing sludges. The aim of this study was to characterize the chemical and microbial composition of the sludge found in a biodiesel storage tank. The material was ...

    • Nature of insulating state in the three-band hubbard model : a tight-binding approach 

      Beatrici, Anderson; Gusmao, Miguel Angelo Cavalheiro (1995) [Artigo de periódico]
      We study the three-band Hubbard model, commonly used to describe the copper-oxygen planes of high-Tc superconductors, from the point of view of electronic properties. Utilizing perturbation theory around the atomic limit ...

    • Nature of long-range order in stripe-forming systems with long-range repulsive interactions 

      Mendoza Coto, Alejandro; Stariolo, Daniel Adrian; Nicolao, Lucas (2015) [Artigo de periódico]
      We study two dimensional stripe forming systems with competing repulsive interactions decaying as r−α.We derive an effective Hamiltonian with a short-range part and a generalized dipolar interaction which depends on the ...

    • Navigation and interaction in graph visualizations 

      Spritzer, Andre Suslik; Freitas, Carla Maria Dal Sasso (2008) [Artigo de periódico]
      Grafos são bastante utilizados em muitas áreas e diversas aplicações requerem sua visualização. A visualização de grafos é baseada em técnicas para desenho de grafos, interação e navegação, de forma que se auxilie o usuário ...

    • Nearest neighbor : the low-mass Milky Way satellite Tucana III 

      Simon, Josh D.; Li, T. S.; Drlica-Wagner, Alex; Bechtol, Keith; Marshall, Jennifer L.; James, David J.; Wang, M.; Strigari, Louis E.; Balbinot, Eduardo; Kuehn, Kyler; Walker, Alistair; Abbott, Timothy M. C.; Allam, Sahar S.; Annis, James T.; Benoit-Lévy, Aurélien; Brooks, D.; Buckley-Geer, Elizabeth; Burke, David Lyle; Carnero Rosell, Aurelio; Carrasco Kind, Matías; Carretero Palacios, Jorge; Cunha, Carlos Eduardo; D'Andrea, Christopher B.; Costa, Luiz N. da; DePoy, Darren L.; Desai, S.; Doel, Peter; Fernandez, Enrique; Flaugher, Brenna; Frieman, Joshua A.; García-Bellido, Juan; Gaztañaga, Enrique; Goldstein, Daniel Abraham; Gruen, Daniel; Gutierrez, Gaston R.; Kuropatkin, Nikolay P.; Maia, Marcio Antonio Geimba; Martini, Paul; Menanteau, Felipe; Miller, Christopher J.; Miquel, Ramon; Neilsen, Eric H.; Nord, Brian Dennis; Ogando, Ricardo L.C.; Plazas Malagón, Andrés Alejandro; Romer, Anita K.; Rykoff, Eli; Sanchez-Alvaro, Eusebio; Santiago, Basilio Xavier; Scarpine, Victor Emanuel; Schubnell, Michael; Sevilla Noarbe, Ignacio; Smith, Robert Christopher; Sobreira, Flávia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Whiteway, L.; Yanny, Brian; DES Collaboration (2017) [Artigo de periódico]
      We present Magellan/IMACS spectroscopy of the recently discovered Milky Way satellite TucanaIII (Tuc III). We identify 26 member stars in TucIII from which we measure a mean radial velocity of vhel=−102.3±0.4 (stat.)±2.0(sys.) ...

    • Near-infrared coronal lines in narrow-line Seyfert 1 galaxies 

      Rodriguez-Ardila, Alberto; Viegas, Sueli Maria Marino; Pastoriza, Miriani Griselda; Prato, Lisa A. (2002) [Artigo de periódico]
      We report spectroscopic observations in the wavelength region 0.8–2.4 μm aimed at detecting near-infrared coronal lines in a sample of five narrow-line and one broad-line Seyfert 1 galaxies. Our measurements show that [Si ...

    • Near-infrared integrated spectra of Galactic globular clusters : testing simple stellar population models 

      Riffel, Rogério; Dutra, Daniel Ruschel; Pastoriza, Miriani Griselda; Rodriguez-Ardila, Alberto; Santos Junior, Joao Francisco Coelho dos; Bonatto, Charles Jose; Ducati, Jorge Ricardo (2011) [Artigo de periódico]
      We present SOAR/OSIRIS cross-dispersed near-infrared (NIR) integrated spectra of 12 Galactic globular clusters that are employed to test Maraston NIR evolutionary population synthesis models, and to provide spectral ...

    • Near infrared photometric and optical spectroscopic study of 22 low mass star clusters embedded in nubulae 

      Soares, Jules Batista; Bica, Eduardo Luiz Damiani; Ahumada, Andrea Veronica; Claria Olmedo, Juan Jose (2008) [Artigo de periódico]
      Aims. Among the star clusters in the Galaxy, those embedded in nebulae represent the youngest group, which has only recently been explored. The analysis of a sample of 22 candidate embedded stellar systems in reflection ...

    • Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators 

      Cohen, Roger; Moni Bidin, Christian; Mauro, Francesco; Bonatto, Charles Jose; Geisler, Doug (2017) [Artigo de periódico]
      We present wide-field JHKS photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the Two Micron All-Sky Survey photometric system. Differential reddening corrections and statistical ...

    • Near-infrared spectral properties of star clusters and galactic nuclei 

      Bica, Eduardo Luiz Damiani; Alloin, Danielle Marie (1987) [Artigo de periódico]
      We present CCD spectra with 12.5 A resolution from 6300 to 9700 Å of 30 star clusters covering ranges 106 to 1.65 1010 yr in age, and -2.0 to 0.1 in metallicity, [Z/Zʘ]. As well, 62 galactic nuclei have been observed in ...

    • Near-infrared study of new embedded clusters in the Carina complex 

      Oliveira, Raphael Augusto Pereira de; Bica, Eduardo Luiz Damiani; Bonatto, Charles Jose (2018) [Artigo de periódico]
      We analyse the nature of a sample of stellar overdensities that we found projected on the Carina complex. This study is based on the Two Micron All Sky Survey photometry and involves the photometry decontamination of field ...

    • Near-infrared surface photometry of early-type galaxies 

      Rembold, Sandro Barboza; Pastoriza, Miriani Griselda; Ducati, Jorge Ricardo; Rubio, Monica; Roth, Miguel (2002) [Artigo de periódico]
      CCD infrared (JHKs) photometry was performed on a sample of 10 elliptical and 2 lenticular galaxies. Isophotal parameters, brightness profiles, integrated colors and color gradients arepresented. Color gradients found arevery ...

    • Negative differential magnetization for Ni nanoparticles in Al 

      Fonda, Emiliano; Teixeira, Sergio Ribeiro; Geshev, Julian Penkov; Babonneau, David; Pailloux, Frederic; Traverse, Agnes (2005) [Artigo de periódico]
      Using a layer-by-layer deposition technique, Ni thin films were sandwiched between AlOx layers in an Al matrix. By using x-ray-absorption spectroscopy, grazing incidence small-angle x-ray scattering, and highresolution ...

    • Negative remanent magnetization of fine particles with competing cubic and uniaxial anisotropies 

      Geshev, Julian Penkov; Viegas, Alexandre da Cas; Schmidt, Joao Edgar (1998) [Artigo de periódico]
      The magnetic properties of noninteracting single-domain particles whose anisotropy is made up of a cubic magnetocrystalline and a uniaxial components were investigated. Various directions of the uniaxial anisotropy were ...

    • Negative rotatable anisotropy in IrMn/Cr/Co thin films 

      Nicolodi, Sabrina; Pereira, Luis Gustavo; Oliveira, Artur Harres de; Azevedo, Gustavo de Medeiros; Schmidt, Joao Edgar; García Aguilar, I.; Souza Neto, N. M.; Deranlot, Cyrile; Petroff, Frédéric; Geshev, Julian Penkov (2012) [Artigo de periódico]
      This work presents modifications of the magnetic properties of polycrystalline IrMn/Cr(tCr)/Co films where the Cr spacer thickness tCr was varied between 0.25 and 3 nm. High-resolution transmission electron microscopy, ...

    • Nematic phase in stripe-forming systems within the self-consistent screening approximation 

      Barci, Daniel G.; Mendoza Coto, Alejandro; Stariolo, Daniel Adrian (2013) [Artigo de periódico]
      We show that in order to describe the isotropic-nematic transition in stripe-forming systems with isotropic competing interactions of the Brazovskii class it is necessary to consider the next to leading order in a 1/N ...

    • Nematic phase in the J1-J2 square-lattice Ising model in an external field 

      Guerrero Duymovic, Alejandra Isabel; Stariolo, Daniel Adrian; Almarza, Noé G. (2015) [Artigo de periódico]
      The J1-J2 Ising model in the square lattice in the presence of an external field is studied by two approaches: the cluster variation method (CVM) and Monte Carlo simulations. The use of the CVM in the square approximation ...

    • Nematic phase in two-dimensional frustrated systems with power-law decaying interactions 

      Barci, Daniel G.; Ribeiro, Leonardo Rodrigues; Stariolo, Daniel Adrian (2013) [Artigo de periódico]
      We address the problem of orientational order in frustrated interaction systems as a function of the relative range of the competing interactions. We study a spin model Hamiltonian with short-range ferromagnetic interaction ...

    • Network growth for enhanced natural selection 

      Barbosa, Valmir Carneiro; Donangelo, Raul José; Souza, Sergio Ricardo de Azevedo (2009) [Artigo de periódico]
      Natural selection and random drift are competing phenomena for explaining the evolution of populations. Combining a highly fit mutant with a population structure that improves the odds that the mutation spreads through the ...

    • Neural networks with high-order connections 

      Arenzon, Jeferson Jacob; Almeida, Rita Maria Cunha de (1993) [Artigo de periódico]
      We present results for two difFerent kinds of high-order connections between neurons acting as corrections to the Hopfield model. Equilibrium properties are analyzed using the replica mean-field theory and compared with ...