349 research outputs found

    Simultaneous production of biochar and thermal energy using palm oil residual biomass as feedstock in an auto-thermal prototype reactor

    Get PDF
    In developing countries, the technology used for biomass carbonization requires major retrofits for an efficient conversion of the residual biomass produced in the palm oil mills into biochar. This study analyzes a prototype of a small and modular auger reactor (P-SMART) that uses untreated kernel shells as feedstock to produce biochar and thermal energy. The P-SMART does not require inert gases during operation, neither diesel nor natural gas for the initial heating process. This study shows that the carbonization process can be driven by the energy generated during pyrolysis gas combustion (auto-thermal conditions) from a biomass load capacity of 30 kg/h. During the auto-thermal operation, the thermal energy generated by pyrolysis gas combustion is higher than that required by the carbonization process. The carbon monoxide concentration in the flue gas during the auto-thermal operation was 197 mg/Nm3 which is lower than the European eco-design requirement of 500 mg/Nm3 (both measured at 11% vol. O2, dry gas). The biochars produced during auto-thermal operation have a macro-porous structure with a pore radius that ranges from 0.42 to 12.48 ÎŒm. The carbon content and the molar H/Corg and O/Corg ratio of the analyzed biochars are in accordance with the European guidelines for the sustainable production of biochar of less than 0.7 and 0.4 respectively. Moreover, relevant soil nutrients were observed in the KS ash, namely: silica (30 wt%), potassium (8.2 wt%) and phosphorous (3 wt%).publishe

    Relief evolution of the Quadrilatero Ferrifero (Minas Gerais, Brazil) by means of (Be-10) cosmogenic nuclei

    Get PDF
    This paper investigates the evolution of the relief within the so-called Iron Quadrangle (Quadrilatero Ferrifero) in Minas Gerais, Brazil, by means of quantification of erosion processes, which affected the principal rock types of the region. The method used is based on measurement of in-situ produced cosmogenic Be-10 concentration in fluvial sediments. The results indicate that the regional landscape evolution is controlled by lithotypes: the most resistant areas correspond to substrates developed on itabirites and quartzites (long-term erosion rates between 0.29 to 2.35 m/My), whereas the most fragile ones developed on schistphyllitcs (long-term erosion rates between 7.95 to 11.82 m/My) and granite-gneisses (long-term erosion rate at 12.92 m/My)

    A new primitive Neornithischian dinosaur from the Jurassic of Patagonia with gut contents

    Get PDF
    We describe a new species of an ornithischian dinosaur, Isaberrysaura mollensis gen. et sp. nov. The specimen, consisting in an almost complete skull and incomplete postcranium was collected from the marine-deltaic deposits of the Los Molles Formation (Toarcian-Bajocian), being the first reported dinosaur for this unit, one of the oldest from Neuquén Basin, and the first neornithischian dinosaur known from the Jurassic of South America. Despite showing a general stegosaurian appearance, the extensive phylogenetic analysis carried out depicts Isaberrysaura mollensis gen. et sp. nov. as a basal ornithopod, suggesting that both Thyreophora and neornithischians could have achieved significant convergent features. The specimen was preserved articulated and with some of its gut content place in the middle-posterior part of the thoracic cavity. Such stomach content was identified as seeds, most of them belonging to the Cycadales group. This finding reveals a possible and unexpected role of this ornithischian species as seed-dispersal agent

    Palm oil kernel shell as solid fuel for the commercial and industrial sector in Ecuador: tax incentive impact and performance of a prototype burner

    Get PDF
    The Ecuadorian industrial and commercial sectors are in general supported in the use of diesel for energy purposes. An alternative to replace diesel could be the use of palm oil residual biomass as solid fuel. It is estimated that 57.7% of the capital costs required to implement a biomass boiler that use untreated palm oil kernel shell (KS) as fuel in replacement of a diesel boiler would be covered by in force tax incentives. Nonetheless, untaxed and subsidized diesel utilization coupled to the important capital and operating costs associated to the biomass boiler results in relatively high payback periods, within the range of 6 to 7.9 years. Analyzing a base case, it is observed that replacement of diesel by KS results in a reduction of 8 times the fuel costs. Implementation of pre-treatment processes (e.g. pelletizing) could increase the KS price, affecting the potential to lower the costs of thermal energy production. Accordingly, utilization of raw KS for thermal energy production was demonstrated using a horizontal burner prototype. The experimental analysis of the KS combustion process shows that combustion efficiency (99.8%) is as high as that observed in other type of biomass burners. During the steady state operation periods, CO concentration in the flue gases (260.1 mg/Nm3) was below the limit established by the European standards for solid fuel boilers (500 mg/Nm3). Ash sintering was observed in the grate during the combustion experiments. The ash discharge process induced periodic fluctuations in the combustion chamber temperature profile as well as fluctuations in the flue gas composition. Despite these localized and periodic temperature and gas composition fluctuations, in the whole, and considering longer periods of operation, the combustion system was under steady state conditions and showed to be suitable for energetic valorization of untreated KS.publishe

    Combinatorial activity of flavonoids with antibiotics against drug resistant Staphylococcus aureus

    Get PDF
    The use of resistance-modifying agents is a potential strategy that is used to prolong the effective life of antibiotics in the face of increasing antibiotic resistance. Since certain flavonoids are potent bacterial efflux pump inhibitors, we assessed morin, rutin, quercetin, hesperidin, and (+)-catechin for their combined activity with the antibiotics ciprofloxacin, tetracycline, erythromycin, oxacillin, and ampicillin against drug-resistant strains of Staphylococcus aureus, including methicillin-resistant S. aureus. Four established methods were used to determine the combined efficacy of each combination: microdilution checkerboard assays, time-kill determinations, the Etest, and dual disc-diffusion methods. The cytotoxicity of the flavonoids was additionally evaluated in a mouse fibroblast cell line. Quercetin and its isomer morin decreased by 3- to 16-fold the minimal inhibitory concentration of ciprofloxacin, tetracycline, and erythromycin against some S. aureus strains. Rutin, hesperidin, and (+)-catechin did not promote any potentiation of antibiotics. Despite the potential cytotoxicity of these phytochemicals at a high concentration (fibroblast IC50 of 41.8 and 67.5mg/L, respectively), quercetin is commonly used as a supplement for several therapeutic purposes. All the methods, with exception of the time-kill assay, presented a high degree of congruence without any apparent strain specificity.This work was supported by Operational Program for Competitiveness Factors—COMPETE, FCT/MEC (PIDDAC), and FEDER through Projects Bioresist—PTDC/EBB-EBI/ 105085/2008; Phytodisinfectants—PTDC/DTP-SAP/1078/ 2012 (COMPETE: FCOMP-01-0124-FEDER-028765) and the PhD grants awarded to Ana Abreu (SFRH/BD/84393/ 2012) and Anabela Borges (SFRH/BD/63398/2009). The authors are very grateful to Professor Simon Gibbons (De- partment of Pharmaceutical and Biological Chemistry, The School of Pharmacy, UCL School of Pharmacy, London) for providing the bacterial strains.info:eu-repo/semantics/publishedVersio

    Shadowing in Inelastic Scattering of Muons on Carbon, Calcium and Lead at Low XBj

    Full text link
    Nuclear shadowing is observed in the per-nucleon cross-sections of positive muons on carbon, calcium and lead as compared to deuterium. The data were taken by Fermilab experiment E665 using inelastically scattered muons of mean incident momentum 470 GeV/c. Cross-section ratios are presented in the kinematic region 0.0001 < XBj <0.56 and 0.1 < Q**2 < 80 GeVc. The data are consistent with no significant nu or Q**2 dependence at fixed XBj. As XBj decreases, the size of the shadowing effect, as well as its A dependence, are found to approach the corresponding measurements in photoproduction.Comment: 22 pages, incl. 6 figures, to be published in Z. Phys.

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

    Get PDF
    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

    Get PDF
    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio
    • 

    corecore