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Physical review / D covering particles, fields, gravitation, and cosmology 93(7), 072006(2016). doi:10.1103/PhysRevD.93.072006, The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, (secθ)max, sensitive to the mass composition of cosmic rays above 3×1018 eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modeling that must be resolved before the mass composition can be inferred from (secθ)max., Published by Inst., Woodbury, NY

p.1-25 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2015-03-18T14:53:20Z No. of bitstreams: 1 P. Abreu.pdf: 1881347 bytes, checksum: 62011ea96251920844896cd2a116a014 (MD5) Approved for entry into archive by Alda Lima da Silva (sivalda@ufba.br) on 2015-03-20T16:23:51Z (GMT) No. of bitstreams: 1 P. Abreu.pdf: 1881347 bytes, checksum: 62011ea96251920844896cd2a116a014 (MD5) Made available in DSpace on 2015-03-20T16:23:52Z (GMT). No. of bitstreams: 1 P. Abreu.pdf: 1881347 bytes, checksum: 62011ea96251920844896cd2a116a014 (MD5) Previous issue date: 2014 We report a study of the distributions of the depth of maximum, Xmax, of extensive air-shower profiles with energies above 1017.8 eV as observed with the fluorescence telescopes of the Pierre Auger Observatory. The analysis method for selecting a data sample with minimal sampling bias is described in detail as well as the experimental cross-checks and systematic uncertainties. Furthermore, we discuss the detector acceptance and the resolution of the Xmax measurement and provide parametrizations thereof as a function of energy. The energy dependence of the mean and standard deviation of the Xmax distributions are compared to air-shower simulations for different nuclear primaries and interpreted in terms of the mean and variance of the logarithmic mass distribution at the top of the atmosphere.

Texto completo: acesso restrito. p. 92–101 Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2014-04-03T12:20:30Z No. of bitstreams: 1 1-s2.0-S0927650513001461-main.pdf: 2074310 bytes, checksum: 1bb9bdbf791773b4514062c7f3b5dee2 (MD5) Approved for entry into archive by Alda Lima da Silva (sivalda@ufba.br) on 2014-09-08T21:00:19Z (GMT) No. of bitstreams: 1 1-s2.0-S0927650513001461-main.pdf: 2074310 bytes, checksum: 1bb9bdbf791773b4514062c7f3b5dee2 (MD5) Made available in DSpace on 2014-09-08T21:00:19Z (GMT). No. of bitstreams: 1 1-s2.0-S0927650513001461-main.pdf: 2074310 bytes, checksum: 1bb9bdbf791773b4514062c7f3b5dee2 (MD5) Previous issue date: 2013 We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km2 of the Pierre Auger Observatory twice per hour with a spatial resolution of ∼2.4 km by ∼5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories.

Texto completo: acesso restrito. p. 649–657 Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2014-04-01T13:25:46Z No. of bitstreams: 1 1-s2.0-S0973082613000719-main.pdf: 1155251 bytes, checksum: cc9e6d8b18ddc91ad445f2ac869d46d3 (MD5) Approved for entry into archive by Rodrigo Meirelles (rodrigomei@ufba.br) on 2014-09-09T14:59:37Z (GMT) No. of bitstreams: 1 1-s2.0-S0973082613000719-main.pdf: 1155251 bytes, checksum: cc9e6d8b18ddc91ad445f2ac869d46d3 (MD5) Made available in DSpace on 2014-09-09T14:59:37Z (GMT). No. of bitstreams: 1 1-s2.0-S0973082613000719-main.pdf: 1155251 bytes, checksum: cc9e6d8b18ddc91ad445f2ac869d46d3 (MD5) Previous issue date: 2013 This work shows the performance and emissions profile of a diesel engine operating with ethanol injected into the air of the inlet manifold in time with the high-pressure injection of a mixture of diesel and biodiesel. The ethanol injection uses an electronic management system that detects the high-pressure pulse in the diesel injection line as the injection trigger. The air intake temperature reduction caused by the ethanol injection could be evaluated. The tests were made in an engine at 1800 rpm, connected to an electric generator. The high-pressure injection fuel was always a binary blend of diesel and biodiesel, which was supplemented by injected ethanol, producing 5 different fuel compositions. The first of the tested compositions was the binary blend without ethanol, while the others had increasing alcohol content. The fifth composition used 15% of ethanol but had a 0.4% of the additive di-tert-butyl peroxide mixed in the main fuel. The addition of ethanol led to a reduction in diesel fuel consumption, although the overall energy expenditure was increased. The emissions profile showed a consistent reduction in NOx emissions and opacity with the addition of ethanol, breaking up the traditional inverse relationship between NOx and PM emissions, but shown an increase in CO and THC emissions. The energy analysis showed a decrease in engine efficiency with the addition of ethanol. The use of the additive showed a slight increase of engine efficiency and the reduction of the CO and THC emissions. There was a significant reduction in the air intake temperature with the use of ethanol, suggesting that part of the reduction of NOx may be attributed to this temperature reduction. It was proven that the ethanol addition can be an important method to reduce the amount of NOx in the exhaust gases of diesel engines.

p. 1373-1379 Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-10-14T18:30:23Z No. of bitstreams: 1 2222222.pdf: 860709 bytes, checksum: 85f880f9836475b9f25aa3cd8478665e (MD5) Made available in DSpace on 2013-10-14T18:30:23Z (GMT). No. of bitstreams: 1 2222222.pdf: 860709 bytes, checksum: 85f880f9836475b9f25aa3cd8478665e (MD5) Previous issue date: 2013 Nesse estudo um planejamento experimental de misturas de biodieseis é utilizado para avaliar e otimizar a estabilidade oxidativa de amostras de biodiesel de soja contendo diferentes teores de biodiesel de sebo e de mamona. As misturas de biodieseis foram preparadas com teores que variaram entre 80-86% (v/v) para a soja, 5-15% (v/v) para o sebo e 1-10% (v/v) para a mamona. O período de indução da amostra de biodiesel de soja puro serviu de base para a comparação com a estabilidade das misturas. A estratégia de planejamento experimental de misturas mostrou-se adequada para a formulação de misturas de biodiesel com ótima estabilidade oxidativa. O modelo quadrático obtido na etapa de otimização ajustou-se adequadamente aos dados experimentais, sendo capaz de prever as proporções ótimas para misturas com maior estabilidade oxidativa. O melhor período de indução foi obtido com as seguintes proporções: 82,5% (v/v) de soja, 7,5% (v/v) de sebo e 10,0% (v/v) de mamona. This study proposes an experimental design of biodiesel constrained mixtures to evaluate and optimize the oxidative stability of soybean biodiesel mixed with different amounts of tallow and castor bean biodiesels. To prepare the biodiesel blends, the proportions of each type of biodiesel were varied, producing mixtures that contained 80-86% (v/v) soybean, 5-15% (v/v) tallow, and 1-10% (v/v) castor bean biodiesel. The induction period of pure soybean biodiesel served as the baseline for comparing the stability of the mixtures. The experimental design strategy was capable of producing the best oxidative stability for biodiesel mixtures. The quadratic model obtained in the optimization stage fits the experimental data well. The higher induction period occurred at the following composition: 82.5% (v/v) soybean, 7.5% (v/v) tallow and 10.0% (v/v) castor bean. Salvador

Texto completo. Acesso restrito. p. 117–124 Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-06-26T13:31:02Z No. of bitstreams: 1 222222222222.pdf: 1169758 bytes, checksum: 9a29ff82116535957ee24667b9b5d00c (MD5) Made available in DSpace on 2013-06-26T13:31:02Z (GMT). No. of bitstreams: 1 222222222222.pdf: 1169758 bytes, checksum: 9a29ff82116535957ee24667b9b5d00c (MD5) Previous issue date: 2013 Solid acid–base sensors were prepared by encapsulating alizarin red pH indicator within a silica matrix using the sol–gel method with four different routes: (1) non-hydrolytic, (2) acid catalyzed, (3) basic catalyzed and (4) without catalyst hydrolytic. The silica–indicator interactions in the resulting materials were investigated by cyclic and differential pulse voltammetry. Ultraviolet–visible photoacoustic spectroscopy was also employed in the characterization. The absorption band shift (49 to 72 nm, depending on the route) between neat alizarin and alizarin encapsulated within the silica network was observed. The electrochemical behavior and the pH indicator interactions with the silica network were dependent on the nature of the employed sol–gel route. For the sensors prepared by the acid and hydrolytic (without catalyst) routes, the interactions with the silica network occurred through alizarin red hydroxyl groups. For the basic route, different cathodic and anodic peaks were observed depending on the pH, suggesting different phenomena during preparation or analysis. In the non-hydrolytic route, it is possible that the quinone form of alizarin red was consumed during the process. The voltammetric results were related to the sensor performance, whereby the acid route produced a solid sensor with the shortest response time, probably because alizarin structure was preserved after the synthetic process. Salvador

p. 1373-1379 Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-10-14T18:30:23Z No. of bitstreams: 1 2222222.pdf: 860709 bytes, checksum: 85f880f9836475b9f25aa3cd8478665e (MD5) Made available in DSpace on 2013-10-14T18:30:23Z (GMT). No. of bitstreams: 1 2222222.pdf: 860709 bytes, checksum: 85f880f9836475b9f25aa3cd8478665e (MD5) Previous issue date: 2013 Nesse estudo um planejamento experimental de misturas de biodieseis é utilizado para avaliar e otimizar a estabilidade oxidativa de amostras de biodiesel de soja contendo diferentes teores de biodiesel de sebo e de mamona. As misturas de biodieseis foram preparadas com teores que variaram entre 80-86% (v/v) para a soja, 5-15% (v/v) para o sebo e 1-10% (v/v) para a mamona. O período de indução da amostra de biodiesel de soja puro serviu de base para a comparação com a estabilidade das misturas. A estratégia de planejamento experimental de misturas mostrou-se adequada para a formulação de misturas de biodiesel com ótima estabilidade oxidativa. O modelo quadrático obtido na etapa de otimização ajustou-se adequadamente aos dados experimentais, sendo capaz de prever as proporções ótimas para misturas com maior estabilidade oxidativa. O melhor período de indução foi obtido com as seguintes proporções: 82,5% (v/v) de soja, 7,5% (v/v) de sebo e 10,0% (v/v) de mamona. This study proposes an experimental design of biodiesel constrained mixtures to evaluate and optimize the oxidative stability of soybean biodiesel mixed with different amounts of tallow and castor bean biodiesels. To prepare the biodiesel blends, the proportions of each type of biodiesel were varied, producing mixtures that contained 80-86% (v/v) soybean, 5-15% (v/v) tallow, and 1-10% (v/v) castor bean biodiesel. The induction period of pure soybean biodiesel served as the baseline for comparing the stability of the mixtures. The experimental design strategy was capable of producing the best oxidative stability for biodiesel mixtures. The quadratic model obtained in the optimization stage fits the experimental data well. The higher induction period occurred at the following composition: 82.5% (v/v) soybean, 7.5% (v/v) tallow and 10.0% (v/v) castor bean. Salvador

p. 1-11 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-04-24T13:13:06Z No. of bitstreams: 1 I. M. Pepe.pdf: 1808285 bytes, checksum: f5e91af383bce3aa10fccedd075927a6 (MD5) Made available in DSpace on 2014-04-24T13:13:06Z (GMT). No. of bitstreams: 1 I. M. Pepe.pdf: 1808285 bytes, checksum: f5e91af383bce3aa10fccedd075927a6 (MD5) Previous issue date: 2012 A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from –90° to +15° in declination using four different energy ranges above 1 EeV (1018 eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultrahigh energy cosmic rays in the Galaxy.

Texto completo: acesso restrito. p. 1-42 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-05-29T12:30:32Z No. of bitstreams: 1 P. Abreu.pdf: 2453261 bytes, checksum: b6ee303833c05e921f336e35ae5dc97f (MD5) Made available in DSpace on 2014-05-29T12:30:32Z (GMT). No. of bitstreams: 1 P. Abreu.pdf: 2453261 bytes, checksum: b6ee303833c05e921f336e35ae5dc97f (MD5) Previous issue date: 2012 The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal.

Texto completo: acesso restrito. p. 1-7 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-07-28T12:27:15Z No. of bitstreams: 1 P. Abreu.pdf: 423423 bytes, checksum: ca3834165cb729afedbfd0935ce0c886 (MD5) Made available in DSpace on 2014-07-28T12:27:15Z (GMT). No. of bitstreams: 1 P. Abreu.pdf: 423423 bytes, checksum: ca3834165cb729afedbfd0935ce0c886 (MD5) Previous issue date: 2012 The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy E ν between 1017 eV and 1020 eV from point-like sources across the sky south of +55° and north of –65° declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth's crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of ~3.5 years of a full surface detector array for the Earth-skimming channel and ~2 years for the downward-going channel. An improved upper limit on the diffuse flux of tau neutrinos has been derived. Upper limits on the neutrino flux from point-like sources have been derived as a function of the source declination. Assuming a differential neutrino flux k PS centerdot E –2 ν from a point-like source, 90% confidence level upper limits for k PS at the level of ≈5 × 10–7 and 2.5 × 10–6 GeV cm–2 s–1 have been obtained over a broad range of declinations from the searches for Earth-skimming and downward-going neutrinos, respectively.

Texto completo: acesso restrito. p. 591–607 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-08-18T13:37:02Z No. of bitstreams: 1 P. Abreu.pdf: 1153609 bytes, checksum: e30a1ef76c25078f6e01725ecb72c9fb (MD5) Made available in DSpace on 2014-08-18T13:37:02Z (GMT). No. of bitstreams: 1 P. Abreu.pdf: 1153609 bytes, checksum: e30a1ef76c25078f6e01725ecb72c9fb (MD5) Previous issue date: 2012 Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malargüe and averaged monthly models, the utility of the GDAS data is shown.

Texto completo: acesso restrito. p. 1-14 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-08-13T15:41:41Z No. of bitstreams: 1 P. Abreu.pdf: 397455 bytes, checksum: f6cab009ae2da7c5b9b9863754ab8c8f (MD5) Made available in DSpace on 2014-08-13T15:41:41Z (GMT). No. of bitstreams: 1 P. Abreu.pdf: 397455 bytes, checksum: f6cab009ae2da7c5b9b9863754ab8c8f (MD5) Previous issue date: 2012 Observations of cosmic ray arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Véron-Cetty Véron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt–L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three methods can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. Using data taken from January 1, 2004 to July 31, 2010 we examined the 20,30,...,110 highest energy events with a corresponding minimum energy threshold of about 49.3 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.

Texto completo: acesso restrito. p. 1593–1596 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-08-04T13:06:39Z No. of bitstreams: 1 Iuri Pepe.pdf: 253513 bytes, checksum: 06c716cede886a23d02ff0a11a4ced54 (MD5) Approved for entry into archive by Alda Lima da Silva (sivalda@ufba.br) on 2014-09-03T17:12:50Z (GMT) No. of bitstreams: 1 Iuri Pepe.pdf: 253513 bytes, checksum: 06c716cede886a23d02ff0a11a4ced54 (MD5) Made available in DSpace on 2014-09-03T17:12:50Z (GMT). No. of bitstreams: 1 Iuri Pepe.pdf: 253513 bytes, checksum: 06c716cede886a23d02ff0a11a4ced54 (MD5) Previous issue date: 2012 We present the optical absorption spectrum of BiTaO4 using the photo acoustic spectroscopy (PAS) technique and first principles approach. Band gap have been estimated 2.65 and 2.45 eV using PAS method and DFT calculations, respectively. Position of reduction and oxidation level with respect to vacuum level are identified, which shows that BiTaO4 can be used as photocatalyst for hydrogen production. Electronic structure is explained by plotting total density of states (TDOS) (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

p. 1-9 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-07-21T13:35:34Z No. of bitstreams: 1 P. Abreu.pdf: 316515 bytes, checksum: b0e7c5d2f82fb1f56f0faaad066bc61f (MD5) Made available in DSpace on 2014-07-21T13:35:34Z (GMT). No. of bitstreams: 1 P. Abreu.pdf: 316515 bytes, checksum: b0e7c5d2f82fb1f56f0faaad066bc61f (MD5) Previous issue date: 2012 We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505±22(stat)+28−36(syst)] mb is found.

Texto completo: acesso restrito. p. 1328-1337 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-07-29T15:19:18Z No. of bitstreams: 1 Iuri M. Pepe.pdf: 869413 bytes, checksum: 280ac9781b0d6cf55f17e9497c4e4218 (MD5) Made available in DSpace on 2014-07-29T15:19:18Z (GMT). No. of bitstreams: 1 Iuri M. Pepe.pdf: 869413 bytes, checksum: 280ac9781b0d6cf55f17e9497c4e4218 (MD5) Previous issue date: 2012 Regressions based on fluorescence spectroscopy were developed to provide relatively inexpensive and rapid measurements of the concentration, viscosity, and specific gravity of biodiesel-diesel blends. The methods involved obtaining a mathematical model from spectrofluorimetric data and data from a given property (concentration, dynamic viscosity, or specific gravity) using partial least squares (PLS) regression, which was then applied as a model for predicting properties of interest. The predicted concentrations, dynamic viscosities, and specific gravities of the biodiesel-diesel blends were compared with actual values and agreed reasonably well with the obtained results. The models showed high correlation between real and predicted values. The R-square values near 1 indicated excellent model accuracy for predicting concentrations, specific gravities, and dynamic viscosities of biodiesel-diesel blends. The residual distribution did not follow a trend with respect to the predicted variables, indicating an excellent fit to the data.

Texto completo: acesso restrito. p. 61–64 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-07-10T13:15:21Z No. of bitstreams: 1 I. Pepe.pdf: 374693 bytes, checksum: a2014550cbdf71dd09aaba54e2a1602d (MD5) Approved for entry into archive by Alda Lima da Silva (sivalda@ufba.br) on 2014-10-03T18:57:07Z (GMT) No. of bitstreams: 1 I. Pepe.pdf: 374693 bytes, checksum: a2014550cbdf71dd09aaba54e2a1602d (MD5) Made available in DSpace on 2014-10-03T18:57:07Z (GMT). No. of bitstreams: 1 I. Pepe.pdf: 374693 bytes, checksum: a2014550cbdf71dd09aaba54e2a1602d (MD5) Previous issue date: 2012 β-BiTaO4 photosensitized with methylene blue, methyl orange, alizarine and eriochrome black T in order to extend its photoresponse into a visible region and the photocatalytic activity was evaluated for each sensitized material under visible light irradiation. The results demonstrate that β-BiTaO4–methylene blue presented photocatalytic activity with respect to hydrogen production, which opens up prospects for improving systems that are able to drive photocatalytic reaction with visible light illumination to make effective use of solar light (∼45% of visible light) to produce hydrogen from water.

Texto completo: acesso restrito. p. 92–102 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-04-01T15:07:37Z No. of bitstreams: 1 M. Ambrosio.pdf: 1100297 bytes, checksum: 3802947cad3dae38b78e6e0f7bc1eacb (MD5) Made available in DSpace on 2014-04-01T15:07:37Z (GMT). No. of bitstreams: 1 M. Ambrosio.pdf: 1100297 bytes, checksum: 3802947cad3dae38b78e6e0f7bc1eacb (MD5) Previous issue date: 2011 The advent of the Auger Engineering Radio Array (AERA) necessitates the development of a powerful framework for the analysis of radio measurements of cosmic ray air showers. As AERA performs “radio-hybrid” measurements of air shower radio emission in coincidence with the surface particle detectors and fluorescence telescopes of the Pierre Auger Observatory, the radio analysis functionality had to be incorporated in the existing hybrid analysis solutions for fluorescence and surface detector data. This goal has been achieved in a natural way by extending the existing Auger Offline software framework with radio functionality. In this article, we lay out the design, highlights and features of the radio extension implemented in the Auger Offline framework. Its functionality has achieved a high degree of sophistication and offers advanced features such as vectorial reconstruction of the electric field, advanced signal processing algorithms, a transparent and efficient handling of FFTs, a very detailed simulation of detector effects, and the read-in of multiple data formats including data from various radio simulation codes. The source code of this radio functionality can be made available to interested parties on request.

Texto completo: acesso restrito. p. 266–276 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-02-13T15:05:42Z No. of bitstreams: 1 J. Alvarez-Muñiz.pdf: 644116 bytes, checksum: 6d85a10352e55d272b1c87d8a8f641ee (MD5) Approved for entry into archive by Alda Lima da Silva (sivalda@ufba.br) on 2014-02-21T18:47:26Z (GMT) No. of bitstreams: 1 J. Alvarez-Muñiz.pdf: 644116 bytes, checksum: 6d85a10352e55d272b1c87d8a8f641ee (MD5) Made available in DSpace on 2014-02-21T18:47:26Z (GMT). No. of bitstreams: 1 J. Alvarez-Muñiz.pdf: 644116 bytes, checksum: 6d85a10352e55d272b1c87d8a8f641ee (MD5) Previous issue date: 2011 In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an Extensive Air Shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface array of the Pierre Auger Observatory consisting of a 1.5 km spaced grid of about 1600 water Cherenkov stations. Using Monte Carlo simulations of ultra-high energy showers the LTP functions are derived for energies in the range between 1017 and 1019 eV and zenith angles up to 65°. A parametrization combining a step function with an exponential is found to reproduce them very well in the considered range of energies and zenith angles. The LTP functions can also be obtained from data using events simultaneously observed by the fluorescence and the surface detector of the Pierre Auger Observatory (hybrid events). We validate the Monte Carlo results showing how LTP functions from data are in good agreement with simulations.

Texto completo: acesso restrito. p. 430–434 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-03-12T12:58:22Z No. of bitstreams: 1 Iuri M. Pepe.pdf: 534982 bytes, checksum: 4f0bcd2865330498f023ad6d8a25b280 (MD5) Made available in DSpace on 2014-03-12T12:58:22Z (GMT). No. of bitstreams: 1 Iuri M. Pepe.pdf: 534982 bytes, checksum: 4f0bcd2865330498f023ad6d8a25b280 (MD5) Previous issue date: 2011 Oxidation stability is an important quality parameter for biodiesel. In general, the methods used to evaluate the oxidation stability of oils and biodiesels are time-consuming. This work reports the use of spectrofluorimetry, a fast analytical technique, associated with multivariate data analysis as a powerful analytical tool to prediction of the oxidation stability. The prediction of the oxidation stability showed a good agreement with the results obtained by the EN14112 reference method Rancimat. The models presented high correlation (0.99276 and 0.97951) between real and predicted values. The R2 values of 0.98557 and 0.95943 indicated the accuracy of the models to predict the oxidation stability of soy oil and soy biodiesel, respectively. The residual distribution does not follow a trend with respect to the predicted variables indicating the good quality of the fits.

Texto completo: acesso restrito. p.579−588 Submitted by Rigaud Andréa (andrearigaud16@yahoo.com.br) on 2012-01-11T16:50:20Z No. of bitstreams: 1 fulltext.pdf: 898472 bytes, checksum: 5da8249cdfcdb8c799db8a3b4080807a (MD5) Made available in DSpace on 2012-01-11T16:50:20Z (GMT). No. of bitstreams: 1 fulltext.pdf: 898472 bytes, checksum: 5da8249cdfcdb8c799db8a3b4080807a (MD5) Previous issue date: 2011 The vehicular illumination system has undergone considerable technological advances in recent decades such as the use of a Light Emitting Diode (LED) Adaptive Front-lighting System (AFS), which represents an industry breakthrough in lighting technology and is rapidly becoming one of the most important innovative technologies around the world in the lighting community. This paper presents AFS control alternatives using fuzzy logic (types 1 and 2) to determine its operating parameters taking into consideration the road conditions in the state of São Paulo (Brazil). Fuzzy logic is a well-known extension of the conventional (Boolean) logic that enables the treatment of uncertainty present in the information through the definition of intermediary membership values between the “completely true” and the “completely false”. This technique or modeling strategy is particularly important when a multi-parameter decision must be taken or the decisions are based on the human knowledge. The results show the potential of the methodology proposed and its suitability for light control providing safer nighttime driving.

p. 1-16 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-02-10T13:13:18Z No. of bitstreams: 1 I. M. Pepe.pdf: 1134869 bytes, checksum: 93e7e125c5750a75fd186c5182479baf (MD5) Approved for entry into archive by Alda Lima da Silva (sivalda@ufba.br) on 2014-02-13T18:08:44Z (GMT) No. of bitstreams: 1 I. M. Pepe.pdf: 1134869 bytes, checksum: 93e7e125c5750a75fd186c5182479baf (MD5) Made available in DSpace on 2014-02-13T18:08:44Z (GMT). No. of bitstreams: 1 I. M. Pepe.pdf: 1134869 bytes, checksum: 93e7e125c5750a75fd186c5182479baf (MD5) Previous issue date: 2011 The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an E−2 differential energy spectrum the limit on the single-flavor neutrino is E2dN/dE

Acesso restrito: Texto completo. p. 368-381. Submitted by JURANDI DE SOUZA SILVA (jssufba@hotmail.com) on 2012-03-30T11:58:54Z No. of bitstreams: 1 __ac.els-cdn.com_S092765...ac7893935c08e19df27a388d82e4e.pdf: 376648 bytes, checksum: be6a072788b3df47a324f413223fefe7 (MD5) Made available in DSpace on 2012-03-30T11:58:54Z (GMT). No. of bitstreams: 1 __ac.els-cdn.com_S092765...ac7893935c08e19df27a388d82e4e.pdf: 376648 bytes, checksum: be6a072788b3df47a324f413223fefe7 (MD5) Previous issue date: 2011 The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The ‘‘hybrid” detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such

Texto completo: acesso restrito. p. 256–263 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-02-13T11:49:05Z No. of bitstreams: 1 Zenis Rocha.pdf: 702039 bytes, checksum: 28a2396b4c23f380be2313391561c1dc (MD5) Made available in DSpace on 2014-02-13T11:49:05Z (GMT). No. of bitstreams: 1 Zenis Rocha.pdf: 702039 bytes, checksum: 28a2396b4c23f380be2313391561c1dc (MD5) Previous issue date: 2011 Solid acid–base sensors were prepared by encapsulating two pH indicators (brilliant yellow or acridine) within a silica matrix by the sol–gel method using three different routes: (1) non-hydrolytic, (2) acid catalyzed and (3) base catalyzed. The interactions of the silica-indicator with the resulting materials were then investigated by cyclic and differential pulse voltammetry. Complementary, ultraviolet–visible, photoacoustic spectroscopy was employed for the characterization of the interactions by monitoring the band shifts (bathochromic or hypsochromic, depending on the sol–gel route) between the neat pH indicators and those encapsulated within the silica network. Furthermore, X-ray photoelectron spectroscopy showed that the N 1s binding energy in brilliant yellow was shifted for the material resulting from the acid route. The electrochemical behavior and the pH indicator interactions with the silica network were dependent on the nature of the employed sol–gel route. For the sensors prepared with acridine, the interactions with the silica network took place through the nitrogen group from the pyridinic ring. For the brilliant yellow indicator, different behaviors were observed depending on the route, suggesting different processes during preparation or analysis. For the basic catalyzed and non-hydrolytic routes, it was not possible to assign a specific interaction. Nevertheless, it seemed that interactions might have taken place through the hydroxyl and/or sulphonic groups. Furthermore, for the brilliant yellow sensor prepared through the acid route, it was possible to show that the interaction probably or partially occurred through the azo groups.

p. 6420–6432 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-03-20T12:29:38Z No. of bitstreams: 1 Iuri M. Pepe.pdf: 1077129 bytes, checksum: 6b79bb00725324853a601b90e317ac8b (MD5) Made available in DSpace on 2014-03-20T12:29:38Z (GMT). No. of bitstreams: 1 Iuri M. Pepe.pdf: 1077129 bytes, checksum: 6b79bb00725324853a601b90e317ac8b (MD5) Previous issue date: 2011 Chemical reactivity, photolability, and computational studies of the ruthenium nitrosyl complex with a substituted cyclam, fac-[Ru(NO)Cl2(κ3N4,N8,N11(1carboxypropyl)cyclam)]Cl·H2O((1-carboxypropyl)cyclam = 3-(1,4,8,11-tetraazacyclotetradecan-1-yl)propionic acid)), (I) are described. Chloride ligands do not undergo aquation reactions (at 25 °C, pH 3). The rate of nitric oxide (NO) dissociation (kobs-NO) upon reduction of I is 2.8 s−1 at 25 ± 1 °C (in 0.5 mol L−1HCl), which is close to the highest value found for related complexes. The uncoordinated carboxyl of I has a pKa of [similar]3.3, which is close to that of the carboxyl of the non coordinated (1-carboxypropyl)cyclam (pKa = 3.4). Two additional pKa values were found for I at [similar]8.0 and [similar]11.5. Upon electrochemical reduction or under irradiation with light (λirr = 350 or 520 nm; pH 7.4), I releases NO in aqueous solution. The cyclam ring N bound to the carboxypropyl group is not coordinated, resulting in a fac configuration that affects the properties and chemical reactivities of I, especially as NO donor, compared with analogous trans complexes. Among the computational models tested, the B3LYP/ECP28MDF, cc-pVDZ resulted in smaller errors for the geometry of I. The computational data helped clarify the experimental acid-base equilibria and indicated the most favourable site for the second deprotonation, which follows that of the carboxyl group. Furthermore, it showed that by changing the pH it is possible to modulate the electron density of I with deprotonation. The calculated NO bond length and the Ru/NO charge ratio indicated that the predominant canonical structure is [RuIIINO], but the Ru–NO bond angles and bond index (b.i.) values were less clear; the angles suggested that [RuIINO+] could contribute to the electronic structure of I and b.i. values indicated a contribution from [RuIVNO−]. Considering that some experimental data are consistent with a [RuIINO+] description, while others are in agreement with [RuIIINO], the best description for I would be a linear combination of the three canonical forms, with a higher weight for [RuIINO+] and [RuIIINO].

Acesso restrito: Texto completo. p. 92-102 Submitted by JURANDI DE SOUZA SILVA (jssufba@hotmail.com) on 2012-02-28T13:55:21Z No. of bitstreams: 1 __pdn.sciencedirect.com_....0-S0168900211001276-main.pdf: 705611 bytes, checksum: be1943c8aeefcedd5fa515742b173dc0 (MD5) Made available in DSpace on 2012-02-28T13:55:21Z (GMT). No. of bitstreams: 1 __pdn.sciencedirect.com_....0-S0168900211001276-main.pdf: 705611 bytes, checksum: be1943c8aeefcedd5fa515742b173dc0 (MD5) Previous issue date: 2011 The adventoftheAugerEngineeringRadioArray(AERA)necessitatesthedevelopmentofapowerful frameworkfortheanalysisofradiomeasurementsofcosmicrayairshowers.AsAERAperforms‘‘radio- hybrid’’ measurementsofairshowerradioemissionincoincidencewiththesurfaceparticledetectors and fluorescencetelescopesofthePierreAugerObservatory,theradioanalysisfunctionalityhadtobe incorporatedintheexistinghybridanalysissolutionsforfluorescenceandsurfacedetectordata.This goal hasbeenachievedinanaturalwaybyextendingtheexistingAugerOfflinesoftwareframework with radiofunctionality.Inthisarticle,welayoutthedesign,highlightsandfeaturesoftheradio extensionimplementedintheAugerOfflineframework.Itsfunctionalityhasachievedahighdegreeof sophisticationandoffersadvancedfeaturessuchasvectorialreconstructionoftheelectricfield, advancedsignalprocessingalgorithms,atransparentandefficienthandlingofFFTs,averydetailed simulationofdetectoreffects,andtheread-inofmultipledataformatsincludingdatafromvarious

Trabalho completo: acesso restrito, p. 239–246 Submitted by Bruna Lessa (lessbruna@gmail.com) on 2012-05-14T20:20:09Z No. of bitstreams: 1 (20)1-s2.0-S0370269310001875-main.pdf: 501159 bytes, checksum: 2ef6e672f42baaf0b492895ab50b1402 (MD5) Made available in DSpace on 2012-05-14T20:20:09Z (GMT). No. of bitstreams: 1 (20)1-s2.0-S0370269310001875-main.pdf: 501159 bytes, checksum: 2ef6e672f42baaf0b492895ab50b1402 (MD5) Previous issue date: 2010-03-08 We report a measurement of the flux of cosmic rays with unprecedented precision and statistics using the Pierre Auger Observatory. Based on fluorescence observations in coincidence with at least one surface detector we derive a spectrum for energies above 1018 eV. We also update the previously published energy spectrum obtained with the surface detector array. The two spectra are combined addressing the systematic uncertainties and, in particular, the influence of the energy resolution on the spectral shape. The spectrum can be described by a broken power law E−γ with index γ=3.3 below the ankle which is measured at log10(Eankle/eV)=18.6. Above the ankle the spectrum is described by a power law with index 2.6 followed by a flux suppression, above about log10(E/eV)=19.5, detected with high statistical significance.

p. 1-7 Submitted by Bruna Lessa (lessbruna@gmail.com) on 2012-05-14T20:35:36Z No. of bitstreams: 1 (21)e091101.pdf: 215805 bytes, checksum: ab8f1c362518eae3432fa1d3832b0829 (MD5) Made available in DSpace on 2012-05-14T20:35:36Z (GMT). No. of bitstreams: 1 (21)e091101.pdf: 215805 bytes, checksum: ab8f1c362518eae3432fa1d3832b0829 (MD5) Previous issue date: 2010-03-05 We describe the measurement of the depth of maximum, Xmax⁡, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 1018 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106-21+35) g/cm2/decade below 1018.24±0.05 eV, and (24±3) g/cm2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.