Reaction Chemistry and Kinetics of Corn Stalk Pyrolysis without and with Ga/HZSM-5

The bifunctional Ga/HZSM-5 catalyst has been proven having the capability to increase the selectivity of aromatics production during catalytic pyrolysis of furan and woody biomass. However, the reaction chemistry and kinetics of pyrolysis of herbaceous biomass promoted by Ga/HZSM-5 is rarely reported. Pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) analysis and non-isothermal thermogravimetric analysis at four heating rates were carried out to investigate the decomposition behavior and pyrolysis kinetics of corn stalk without and with Ga/HZSM-5. The effective activation energies for corn stalk pyrolysis were calculated by using the Friedman isoconversional method. The Py–GC/MS analysis results indicated that the Ga/HZSM-5 catalyst had a high selectivity toward producing the aromatic chemicals of xylene, toluene and benzene, whereas the major products from non-catalytic pyrolysis of corn stalk were oxygenated compounds. The presence of Ga/HZSM-5 could significantly reduce the effective activation energies of corn stalk pyrolysis from 159.9–352.4 kJ mol−1 to 41.6–99.8 kJ mol−1 in the conversion range of 0.10–0.85

An indication of anisotropy in arrival directions of utra-high-energy cosmic rays through comparison to the flux pattern of extragalactic gamma-ray sources

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE RIO DE JANEIROFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOMCTIC - MINISTÉRIO DA CIÊNCIA, TECNOLOGIA, INOVAÇÕES E COMUNICAÇÕESA new analysis of the data set from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above 20 EeV with zenith angles up to 80 degrees. recorded before 2017 April 30. Sky models have been created for two distinct populations of extragalactic gamma-ray emitters: active galactic nuclei from the second catalog of hard Fermi-LAT sources (2FHL) and starburst galaxies from a sample that was examined with Fermi-LAT. Flux-limited samples, which include all types of galaxies from the Swift-BAT and 2MASS surveys, have been investigated for comparison. The sky model of cosmic-ray density constructed using each catalog has two free parameters, the fraction of events correlating with astrophysical objects, and an angular scale characterizing the clustering of cosmic rays around extragalactic sources. A maximum-likelihood ratio test is used to evaluate the best values of these parameters and to quantify the strength of each model by contrast with isotropy. It is found that the starburst model fits the data better than the hypothesis of isotropy with a statistical significance of 4.0 sigma, the highest value of the test statistic being for energies above 39 EeV. The three alternative models are favored against isotropy with 2.7 sigma-3.2 sigma significance. The origin of the indicated deviation from isotropy is examined and prospects for more sensitive future studies are discussed.8532110CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE RIO DE JANEIROFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOMCTIC - MINISTÉRIO DA CIÊNCIA, TECNOLOGIA, INOVAÇÕES E COMUNICAÇÕESCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE RIO DE JANEIROFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOMCTIC - MINISTÉRIO DA CIÊNCIA, TECNOLOGIA, INOVAÇÕES E COMUNICAÇÕESSem informaçãoSem informaçãoSem informaçãoSem informaçãoSem informaçãoAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

Inferences on mass composition and tests of hadronic interactions from 0.3 to 100 EeV using the water-Cherenkov detectors of the Pierre Auger Observatory

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPWe present a new method for probing the hadronic interaction models at ultrahigh energy and extracting details about mass composition. This is done using the time profiles of the signals recorded with the water-Cherenkov detectors of the Pierre Auger Observatory. The profiles arise from a mix of the muon and electromagnetic components of air showers. Using the risetimes of the recorded signals, we define a new parameter, which we use to compare our observations with predictions from simulations. We find, first, inconsistencies between our data and predictions over a greater energy range and with substantially more events than in previous studies. Second, by calibrating the new parameter with fluorescence measurements from observations made at the Auger Observatory, we can infer the depth of shower maximum X-max for a sample of over 81,000 events extending from 0.3 to over 100 EeV. Above 30 EeV, the sample is nearly 14 times larger than what is currently available from fluorescence measurements and extending the covered energy range by half a decade. The energy dependence of < X-max gt; is compared to simulations and interpreted in terms of the mean of the logarithmic mass. We find good agreement with previous work and extend the measurement of the mean depth of shower maximum to greater energies than before, reducing significantly the statistical uncertainty associated with the inferences about mass composition.9612122CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçãoSem informação1999/05404-32010/07359-6The successful installation, commissioning, and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and administrative staff in Malargue. We are very grateful to the following agencies and organizations for financial support: (Argentina) Comision Nacional de Energia Atomica; Agencia Nacional de Promocion Cientifica y Tecnologica (ANPCyT); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET); Gobierno de la Provincia de Mendoza; Municipalidad de Malargue; and NDM Holdings and Valle Las Lenas in gratitude for their continuing cooperation over land access; (Australia) the Australian Research Council; (Brazil) Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Financiadora de Estudos e Projetos (FINEP); Fundacao de Amparo a Pesquisa do Estado de Rio de Janeiro (FAPERJ); Sao Paulo Research Foundation (FAPESP) Grants No. 2010/07359-6 and No. 1999/05404-3; Ministerio de Ciencia e Tecnologia (MCT); (Czech Republic) Grants No. MSMT CR LG15014, LO1305, LM2015038, and CZ.02.1.01/0.0/0.0/16\_013/0001402; (France) Centre de Calcul IN2P3/CNRS; Centre National de la Recherche Scientifique (CNRS); Conseil Regional Ile-de-France; Departement Physique Nucleaire et Corpusculaire (PNC-IN2P3/CNRS); Departement Sciences de l'Univers (SDU-INSU/CNRS); Institut Lagrange de Paris (ILP) Grant No. LABEX ANR-10-LABX-63 within the Investissements d'Avenir Programme Grant No. ANR-11-IDEX-0004-02; (Germany) Bundesministerium fur Bildung und Forschung (BMBF); Deutsche Forschungsgemeinschaft (DFG); Finanzministerium Baden-Wurttemberg; Helmholtz Alliance for Astroparticle Physics (HAP); Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF); Ministerium fur Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen; Ministerium fur Wissenschaft, Forschung und Kunst des Landes Baden-Wurttemberg; (Italy) Istituto Nazionale di Fisica Nucleare (INFN); Istituto Nazionale di Astrofisica (INAF); Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR); CETEMPS Center of Excellence; Ministero degli Affari Esteri (MAE); (Mexico) Consejo Nacional de Ciencia y Tecnologia (CONACYT) Grant No. 167733; Universidad Nacional Autonoma de Mexico (UNAM); PAPIIT DGAPA-UNAM; (Netherlands) Ministerie van Onderwijs, Cultuur en Wetenschap; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO); Stichting voor Fundamenteel Onderzoek der Materie (FOM); (Poland) National Centre for Research and Development, Grants No. ERA-NET-ASPERA/01/11 and No. ERA-NET-ASPERA/02/11; National Science Centre, Grants No. 2013/08/M/ST9/00322, No. 2013/08/M/ST9/00728, No. HARMONIA 5-2013/10/M/ST9/00062, and No. UMO-2016/22/M/ST9/00198; (Portugal) Portuguese national funds and FEDER funds within Programa Operacional Factores de Competitividade through Fundacao para a Ciencia e a Tecnologia (COMPETE); (Romania) Romanian Authority for Scientific Research ANCS; CNDI-UEFISCDI partnership projects Grants No. 20/2012, No. 194/2012, and No. PN 16 42 01 02; (Slovenia) Slovenian Research Agency; (Spain) Comunidad de Madrid; Fondo Europeo de Desarrollo Regional (FEDER) funds; Ministerio de Economia y Competitividad; Xunta de Galicia; European Community 7th Framework Program Grant No. FP7-PEOPLE-2012-IEF-328826; (USA) Department of Energy, Contracts No. DE-AC02-07CH11359, No. DE-FR02-04ER41300, No. DE-FG02-99ER41107, and No. DE-SC0011689; National Science Foundation, Grant No. 0450696; The Grainger Foundation; Marie Curie-IRSES/EPLANET (European Union); European Particle Physics Latin American Network; European Union 7th Framework Program, Grant No. PIRSES-2009-GA-246806; European Union's Horizon 2020 Research and Innovation Programme (Grant No. 646623); and UNESCO

The depth of the shower maximum of air showers measured with AERA

The Auger Engineering Radio Array (AERA) is currently the largest array of radio antennas for the detection of cosmic rays, spanning an area of 17 km2 with 153 radio antennas, measuring in the energy range from 1017.0 to 1019.0 eV. It detects the radio emission of extensive air showers produced by cosmic rays in the 30 − 80 MHz band. The cosmic-ray mass composition is a crucial piece of information in determining the sources of cosmic rays and their acceleration mechanisms. The depth of the shower maximum, Xmax, a probe for mass composition can be determined with a likelihood analysis that compares the measured radio-emission footprint on the ground to an ensemble of footprints from CORSIKA/CoREAS Monte-Carlo air shower simulations. These simulations are also used to determine the resolution of the method and to validate the reconstruction by identifying and correcting for systematic uncertainties. We will present the method for the reconstruction of the depth of the shower maximum, achieving a resolution of up to 15 g/cm2, show compatibility with the independent fluorescence detector reconstruction measured on an event-by-event basis, and show that the data taken over the past seven years with AERA shows a light cosmic-ray mass composition reconstruction in the energy range from 1017.5 to 1018.8 eV

The 2021 Open-Data release by the Pierre Auger Collaboration

The Pierre Auger Observatory is used to study the extensive air-showers produced by cosmic rays above 1017 eV. The Observatory is operated by a Collaboration of about 400 scientists, engineers, technicians and students from more than 90 institutions in 18 countries. The Collaboration is committed to the public release of their data for the purpose of re-use by a wide community including professional scientists, in educational and outreach initiatives, and by citizen scientists. The Open Access Data for 2021 comprises 10% of the samples used for results reported at the Madison ICRC 2019, amounting to over 20000 showers measured with the surface-detector array and over 3000 showers recorded simultaneously by the surface and fluorescence detectors. Data are available in pseudo-raw (JSON) format with summary CSV file containing the reconstructed parameters. A dedicated website is used to host the datasets that are available for download. Their detailed description, along with auxiliary information needed for data analysis, is given. An online event display is also available. Simplified codes derived from those used for published analyses are provided by means of Python notebooks prepared to guide the reader to an understanding of the physics results. Here we describe the Open Access data, discuss the notebooks available and show material accessible to the user at https://opendata.auger.org/

Deep-learning based reconstruction of the shower maximum Xmax using the water-Cherenkov detectors of the Pierre Auger Observatory

The atmospheric depth of the air shower maximum Xmax is an observable commonly used for the determination of the nuclear mass composition of ultra-high energy cosmic rays. Direct measurements of Xmax are performed using observations of the longitudinal shower development with fluorescence telescopes. At the same time, several methods have been proposed for an indirect estimation of Xmax from the characteristics of the shower particles registered with surface detector arrays. In this paper, we present a deep neural network (DNN) for the estimation of Xmax. The reconstruction relies on the signals induced by shower particles in the ground based water-Cherenkov detectors of the Pierre Auger Observatory. The network architecture features recurrent long short-term memory layers to process the temporal structure of signals and hexagonal convolutions to exploit the symmetry of the surface detector array. We evaluate the performance of the network using air showers simulated with three different hadronic interaction models. Thereafter, we account for long-term detector effects and calibrate the reconstructed Xmax using fluorescence measurements. Finally, we show that the event-by-event resolution in the reconstruction of the shower maximum improves with increasing shower energy and reaches less than 25 g/cm2 at energies above 2×1019 eV

Operations of the Pierre Auger Observatory

The construction of the first stage of the Pierre Auger Observatory, designed for research of ultra-high energy cosmic rays, began in 2001 with a prototype system. The Observatory has been collecting data since early 2004 and was completed in 2008. The Observatory is situated at 1400 m above sea level near Malargüe, (Mendoza province) in western Argentina, covering a vast plain of 3000 km2, known as the Pampa Amarilla. The Observatory consists of a hybrid detector, in which there are 1660 water-Cherenkov stations, forming the Surface Detector (SD) and 27 peripheral atmospheric fluorescence telescopes, comprising the Fluorescence Detector (FD). Over time, the Auger Observatory has been enhanced with different R&amp;D prototypes and is recently being to an important upgrade called AugerPrime. In the present contribution, the general operations of the SD and FD will be described. In particular the FD shift procedure - executable locally in Malargüe or remotely by teams in control rooms abroad within the Collaboration - and the newly SD shifts (operating since 2019) will be explained. Additionally, the SD and FD maintenance campaigns, as well as the data taking and data handling at a basic level, will be reported

Status and performance of the underground muon detector of the Pierre Auger Observatory

The Auger Muons and Infill for the Ground Array (AMIGA) is an enhancement of the Pierre Auger Observatory, whose purpose is to lower the energy threshold of the observatory down to 1016.5 eV, and to measure the muonic content of air showers directly. These measurements will significantly contribute to the determination of primary particle masses in the range between the second knee and the ankle, to the study of hadronic interaction models with air showers, and, in turn, to the understanding of the muon puzzle. The underground muon detector of AMIGA is concomitant to two triangular grids of water-Cherenkov stations with spacings of 433 and 750 m; each grid position is equipped with a 30 m2 plastic scintillator buried at 2.3 m depth. After the engineering array completion in early 2018 and general improvements to the design, the production phase commenced. In this work, we report on the status of the underground muon detector, the progress of its deployment, and the performance achieved after two years of operation. The detector construction is foreseen to finish by mid-2022

A combined fit of energy spectrum, shower depth distribution and arrival directions to constrain astrophysical models of UHECR sources

The combined fit of the measured energy spectrum and distribution of depths of shower maximum of ultra-high-energy cosmic rays is known to constrain the parameters of astrophysical scenarios with homogeneous source distributions. Further measurements show that the cosmic-ray arrival directions agree better with the directions and fluxes of catalogs of starburst galaxies and active galactic nuclei than with isotropy. Here, we present a novel combination of both analyses. For that, a three-dimensional universe model containing a nearby source population and a homogeneous background source distribution is built, and its parameters are adapted using a combined fit of the energy spectrum, depth of shower maximum distribution and energy-dependent arrival directions. The model takes into account a symmetric magnetic field blurring, source evolution and interactions during propagation. We use simulated data, which resemble measurements of the Pierre Auger Observatory, to evaluate the method’s sensitivity. With this, we are able to verify that the source parameters as well as the fraction of events from the nearby source population and the size of the magnetic field blurring are determined correctly, and that the data is described by the fitted model including the catalog sources with their respective fluxes and three-dimensional positions. We demonstrate that by combining all three measurements we reach the sensitivity necessary to discriminate between the catalogs of starburst galaxies and active galactic nuclei