1,350 research outputs found

    Chicken litter: A waste or a source of chemicals? Fast pyrolysis and hydrothermal conversion as alternatives in the valorisation of poultry waste

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    Poultry production is one of the main and fastest developing branches of the agri-food industry in the world. Chicken litter (ChL) is the most abundant waste from this industry and requires alternative treatments to help mitigate the environmental impacts of improper disposal. Fast pyrolysis and hydrothermal conversion are two recognized thermochemical approaches for the transformation of different types of biomasses, including agro-industrial waste. Fast pyrolysis takes place at atmospheric pressure or under vacuum at moderate to high temperatures (400–800 °C) in the absence of oxygen and requires drying of the feedstock, whereas hydrothermal conversion is a low temperature (180–300 °C) and high pressure (up to 30 MPa) process that takes place in liquid water and particularly suited for moist materials. In this work, we present experimental results that provide a comparison of bio-oils produced by fast pyrolysis and hydrothermal conversion of ChL. In addition, the composition of the pyrolytic oils from ChL is compared with the data obtained from rice husk (the main component of ChL), studied previously. Fast pyrolysis experiments were carried out in a bed reactor at temperatures ranging from 400° to 700°C and at two reaction times of 20- and 40-min. Phenols and other oxygenated compounds were the main families of chemicals present in the bio-oils. Among oxygenated derivatives, fatty acids were predominant. Hydrothermal conversion experiments were performed between 220 and 240 °C for 20- and 40- min and the oil fraction was obtained by evaporation of water from the reaction mixture followed by freeze-drying. These bioliquids were found to be concentrated in fatty acids, especially palmitic acid.EEA Concepción del UruguayFil: Pachón Gómez, Erica M. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Pachón Gómez, Erica M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Domínguez, Rodrigo E. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Domínguez, Rodrigo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: López, Débora A. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: López, Débora A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Téllez, Jhoan F. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Téllez, Jhoan F. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Téllez, Jhoan F. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Marino, Marcos D. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Marino, Marcos D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Almada, Natalia Soledad. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; Argentina.Fil: Gange, Juan Martí­n. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Moyano, E. Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Moyano, E. Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; Argentin

    Plantas medicinais com propriedades anti-helmínticas utilizadas em caprinos.

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    As helmintoses em animais ruminantes representam significativo problema sanitário, tendo em vista o grande número de rebanhos acometidos e as várias alterações orgânicas que podem ocasionar a resistência à medicamentos, mesmo com a diversidade de anti-helmínticos sintéticos usados no seu controle. Devido a este problema, um dos métodos para combater a esses parasitas está na utilidade terapêutica de plantas contra infecções parasitárias nos animais. Portanto, o presente trabalho tem por objetivo realizar o levantamento de plantas medicinais com propriedades anti-helmínticas utilizadas no combate de verminoses em caprinos. Para o início da pesquisa, este trabalho foi desenvolvido na EMBRAPA Amazônia Oriental, onde foram verificados artigos e livros que apontam quais as espécies são usadas no tratamento de doenças parasitárias, após o levantamento, foi elaborada uma tabela (Excel 2010) com as categorias taxonomicas: Família, gênero e espécie. Para complementar a tabela, informações como: nome vulgar e parte utilizada foram acrescentados, em seguida para a confirmação dos nomes científicos foram utilizados sites específicos como MOBOT, LISTA DE ESPÉCIES DO BRASIL e ESPÉCIESLINK. Após o levantamento, foram encontradas 55 espécies vegetais utilizadas em caprinos. Com isso, pode-se analisar que as plantas medicinais são eficientes fitoterápicos para o tratamento de diversas doenças relacionadas aos animais de produção. Porém ainda são necessários mais estudos relacionados à eficiência dos vegetais no tratamento de caprinos

    Mixed integer programming in production planning with backlogging and setup carryover : modeling and algorithms

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    This paper proposes a mixed integer programming formulation for modeling the capacitated multi-level lot sizing problem with both backlogging and setup carryover. Based on the model formulation, a progressive time-oriented decomposition heuristic framework is then proposed, where improvement and construction heuristics are effectively combined, therefore efficiently avoiding the weaknesses associated with the one-time decisions made by other classical time-oriented decomposition algorithms. Computational results show that the proposed optimization framework provides competitive solutions within a reasonable time

    All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

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    We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of 2.49±0.01-2.49\pm0.01 prior to a break at (45.7±0.1(45.7\pm0.1) TeV, followed by an index of 2.71±0.01-2.71\pm0.01. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review

    Dissecting dual roles of MyoD during lineage conversion to mature myocytes and myogenic stem cells

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    The generation of myotubes from fibroblasts upon forced MyoD expression is a classic example of transcription factor-induced reprogramming. We recently discovered that additional modulation of signaling pathways with small molecules facilitates reprogramming to more primitive induced myogenic progenitor cells (iMPCs). Here, we dissected the transcriptional and epigenetic dynamics of mouse fibroblasts undergoing reprogramming to either myotubes or iMPCs using a MyoD-inducible transgenic model. Induction of MyoD in fibroblasts combined with small molecules generated Pax7+ iMPCs with high similarity to primary muscle stem cells. Analysis of intermediate stages of iMPC induction revealed that extinction of the fibroblast program preceded induction of the stem cell program. Moreover, key stem cell genes gained chromatin accessibility prior to their transcriptional activation, and these regions exhibited a marked loss of DNA methylation dependent on the Tet enzymes. In contrast, myotube generation was associated with few methylation changes, incomplete and unstable reprogramming, and an insensitivity to Tet depletion. Finally, we showed that MyoD's ability to bind to unique bHLH targets was crucial for generating iMPCs but dispensable for generating myotubes. Collectively, our analyses elucidate the role of MyoD in myogenic reprogramming and derive general principles by which transcription factors and signaling pathways cooperate to rewire cell identity

    Search for very-high-energy emission from Gamma-ray Bursts using the first 18 months of data from the HAWC Gamma-ray Observatory

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    The High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory is an extensive air shower detector operating in central Mexico, which has recently completed its first two years of full operations. If for a burst like GRB 130427A at a redshift of 0.34 and a high-energy component following a power law with index -1.66, the high-energy component is extended to higher energies with no cut-off other than from extragalactic background light attenuation, HAWC would observe gamma rays with a peak energy of \sim300 GeV. This paper reports the results of HAWC observations of 64 gamma-ray bursts (GRBs) detected by Swift\mathit{Swift} and Fermi\mathit{Fermi}, including three GRBs that were also detected by the Large Area Telescope (Fermi\mathit{Fermi}-LAT). An ON/OFF analysis method is employed, searching on the time scale given by the observed light curve at keV-MeV energies and also on extended time scales. For all GRBs and time scales, no statistically significant excess of counts is found and upper limits on the number of gamma rays and the gamma-ray flux are calculated. GRB 170206A, the third brightest short GRB detected by the Gamma-ray Burst Monitor on board the Fermi\mathit{Fermi} satellite (Fermi\mathit{Fermi}-GBM) and also detected by the LAT, occurred very close to zenith. The LAT measurements can neither exclude the presence of a synchrotron self-Compton (SSC) component nor constrain its spectrum. Instead, the HAWC upper limits constrain the expected cut-off in an additional high-energy component to be less than 100 GeV100~\rm{GeV} for reasonable assumptions about the energetics and redshift of the burst.Comment: 19 pages, 6 figures, published in Ap

    Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory

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    The Crab Nebula is the brightest TeV gamma-ray source in the sky and has been used for the past 25 years as a reference source in TeV astronomy, for calibration and verification of new TeV instruments. The High Altitude Water Cherenkov Observatory (HAWC), completed in early 2015, has been used to observe the Crab Nebula at high significance across nearly the full spectrum of energies to which HAWC is sensitive. HAWC is unique for its wide field-of-view, nearly 2 sr at any instant, and its high-energy reach, up to 100 TeV. HAWC's sensitivity improves with the gamma-ray energy. Above \sim1 TeV the sensitivity is driven by the best background rejection and angular resolution ever achieved for a wide-field ground array. We present a time-integrated analysis of the Crab using 507 live days of HAWC data from 2014 November to 2016 June. The spectrum of the Crab is fit to a function of the form ϕ(E)=ϕ0(E/E0)αβln(E/E0)\phi(E) = \phi_0 (E/E_{0})^{-\alpha -\beta\cdot{\rm{ln}}(E/E_{0})}. The data is well-fit with values of α=2.63±0.03\alpha=2.63\pm0.03, β=0.15±0.03\beta=0.15\pm0.03, and log10(ϕ0 cm2 s TeV)=12.60±0.02_{10}(\phi_0~{\rm{cm}^2}~{\rm{s}}~{\rm{TeV}})=-12.60\pm0.02 when E0E_{0} is fixed at 7 TeV and the fit applies between 1 and 37 TeV. Study of the systematic errors in this HAWC measurement is discussed and estimated to be ±\pm50\% in the photon flux between 1 and 37 TeV. Confirmation of the Crab flux serves to establish the HAWC instrument's sensitivity for surveys of the sky. The HAWC survey will exceed sensitivity of current-generation observatories and open a new view of 2/3 of the sky above 10 TeV.Comment: Submitted 2017/01/06 to the Astrophysical Journa
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