720 research outputs found

    How Wood Fuels\u2019 Quality Relates to the Standards: A Class-Modelling Approach

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    The quality requirements of wood biofuels are regulated by a series of harmonized international standards. These standards define the technical parameter limits that influence the quality of solid biomass as a fuel. In 2014 the European reference standard for solid biofuel was replaced by the International ISO standard. In the case of wood chips, the main difference between the European and International standards is the definition of particle size distribution classes. In this context, this study analyses the quality of wood chips and its variation over the years according to the \u201cformer\u201d (EN 14691-4) and \u201cin force\u201d (ISO 17225-4) standards. A Soft Independent Modelling of Class Analogy (SIMCA) model was built to predict the best quality of wood chips and to clarify the relationship between quality and standard parameters, time and changes in the standard regulations. The results show that, compared to the EN standards, classification with the ISO standards increases the samples belonging to the best quality classes and decreases the not classified samples. Furthermore, all the SIMCA models have a high sensitivity (>90%), reflect the differences introduced to the quality standards and are therefore suitable for monitoring the quality of wood chips and their changes

    Efficacy of a standardized training on horse welfare indicators: a preliminary study

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    Harmonized data collection is essential to obtain a reliable picture of equine welfare conditions. Effective education on how to assess and score welfare indicators plays a critical role in terms of inter-observer reliability. The Horse Grimace Scale (HGS), a facial-expression-based pain coding system, is able to identify a range of acute pain conditions in horses. This study aimed at evaluating the efficacy of a standardized training on HGS inter-observer reliability.Students in Veterinary Medicine from the University of Milan (N=46) and the University of Teramo (N=31) were recruited. Prior to any training, students were asked to score 10 pictures of horse faces using the six Facial Action Units (FAUs) of the HGS: Stiffly backwards ears, Orbital tightening, Tension above the eye area, Prominent strained chewing muscles, Mouth strained, Strained nostrils. Then, a 30-min training session was provided, including detailed descriptions and example pictures of each FAU, as well as a discussion of five pictures previously scored by an experienced assessor. After training, students scored other 10 pictures. To determine the inter-observer reliability pre and post-training, Intra-class Correlation Coefficient (ICC) was used.Students’ reliability was good even before training (ICC=0,986 for the overall HGS score), with Tension above the eye area, and Strained nostrils appearing more challenging to be scored reliably. Reliability improved after the 30 min training for the overall HGS score (ICC=0,992) and for each FAU (see table 1). According to Cicchetti (1994), an ICC score between 0.75 and 1.00 can be considered excellent.Our results suggest that the HGS scoring system is easy to apply even without any training; however, the training method applied proved useful to improve the reliability of HGS scores

    Formation of black holes in the pair-instability mass gap: evolution of a post-collision star

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    The detection of GW190521 by the LIGO-Virgo collaboration revealed the existence of black holes (BHs) in the pair-instability (PI) mass gap. Here, we investigate the formation of BHs in the PI mass gap via star -- star collisions in young stellar clusters. To avoid PI, the stellar-collision product must have a relatively small core and a massive envelope. We generate our initial conditions from the outputs of a hydro-dynamical simulation of the collision between a core helium burning star (58\sim 58 M_\odot) and a main-sequence star (42\sim 42 M_\odot). The hydro-dynamical simulation allows us to take into account the mass lost during the collision (12\sim 12 M_\odot) and to build the chemical composition profile of the post-collision star. We then evolve the collision product with the stellar evolution codes PARSEC and MESA. We find that the post-collision star evolves through all the stellar burning phases until core collapse, avoiding PI. At the onset of core collapse, the post-collision product is a blue super-giant star. We estimate a total mass loss of about 1 M_\odot during the post-collision evolution, due to stellar winds and shocks induced by neutrino emission in a failed supernova. The final BH mass is 87\approx{87} M_\odot. Therefore, we confirm that the collision scenario is a suitable formation channel to populate the PI mass gap.Comment: 9 pages, 6 figures, comments welcome

    Logic-Based Decision Support for Strategic Environmental Assessment

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    Strategic Environmental Assessment is a procedure aimed at introducing systematic assessment of the environmental effects of plans and programs. This procedure is based on the so-called coaxial matrices that define dependencies between plan activities (infrastructures, plants, resource extractions, buildings, etc.) and positive and negative environmental impacts, and dependencies between these impacts and environmental receptors. Up to now, this procedure is manually implemented by environmental experts for checking the environmental effects of a given plan or program, but it is never applied during the plan/program construction. A decision support system, based on a clear logic semantics, would be an invaluable tool not only in assessing a single, already defined plan, but also during the planning process in order to produce an optimized, environmentally assessed plan and to study possible alternative scenarios. We propose two logic-based approaches to the problem, one based on Constraint Logic Programming and one on Probabilistic Logic Programming that could be, in the future, conveniently merged to exploit the advantages of both. We test the proposed approaches on a real energy plan and we discuss their limitations and advantages.Comment: 17 pages, 1 figure, 26th Int'l. Conference on Logic Programming (ICLP'10

    Biofuel Powering of Internal Combustion Engines: Production Routes, Effect on Performance and CFD Modeling of Combustion

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    The use of liquid or gaseous biofuels in reciprocating internal combustion engines (ICEs) is today a relevant issue as these systems are largely diffused for both steady power generation and transportation due to their flexibility and easiness of use. The improvement and perfect control of the combustion process under non-conventional fueling is mandatory to achieve high-energy efficiency without substantial changes to the architecture or the fuel supply system. In this perspective, the detailed characterization of multiphase reacting systems achievable though computational fluid dynamics (CFD) may give a decisive contribution. However, the assessed combustion models used for fossil fuels (diesel oil, gasoline, methane), tuned on the ground of a massive amount of experimental data, often results poor in predicting the actual behavior of renewable fuels whose composition and properties may change also according to technology for their production. Present work aims at filling some existing gaps in biofuel combustion modeling by performing investigations on two representative engine cases, for their characterization and performance enhancement. Two approaches are followed, namely through reduced chemical kinetics coupled with turbulence within a coherent flame schematization, and through a turbulent species transport approach with detailed kinetics. Simulations are first carried out on a compression ignition (CI) ICE. The formulation of a 3D CFD model is described to reproduce the performance of this engine in a dual-fuel mode with premixed syngas from biomass gasification and a biodiesel pilot injection leading to self-ignition. Pollutants formation and energy efficiency are calculated as syngas amount and the biodiesel start of injection (SOI) are varied. Attention is then focused on the implementation of renewable alcohol fuels (ethanol and butanol), as these lasts are receiving large interest due to low production costs. A validated reduced kinetic mechanism for PRF-ethanol-butanol combustion performs well in multi-component oxidation conditions, as well as in neat fuel oxidation conditions, in terms of ignition delay time, laminar flame speed and HCCI combustion conditions. The paper shows that CFD, even at different level of approximation, may describe into detail the combustion process and provide important guidelines for the design of new generation ICEs fuelled by biofuels

    Does poor stunning affect the assessment of animal-based measures consciousness in lambs at slaughter?

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    Oral session 2[EN] According to EU legislation on the killing of animals (EC n. 1099/2009), to ensure that animals do not regain consciousness before slaughter, the efficiency of stunning method must be evaluated through animal-based measures (ABMs)

    EVOLUÇÃO E CARACTERIZAÇÃO DOS NÍVEIS DE POBREZA DO NORDESTE ENTRE 1995 E 2005.

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    Existe um amplo consenso entre cientistas, políticos, pesquisadores e intelectuais de todo o mundo de que a redução da pobreza deve ser vista como uma das prioridades das políticas públicas. Deste modo, a mensuração do nível de pobreza se torna alvo de um intenso debate, na medida em que é necessário primeiramente identificar onde ela está localizada para, em seguida, ter-se condições de combatê-la. Hoje no Brasil esta preocupação se torna mais evidente quando as análises enfocam o espaço econômico do Nordeste, pois esta região é reconhecidamente a mais carente do país. Ao mesmo tempo, é sabido que a partir de meados de 1994 uma nova realidade política foi imposta ao país, acarretando em uma série de conseqüências sobre a população nacional e, automaticamente, também sobre a nordestina. Neste sentido, o presente trabalho tem como objetivo geral mensurar e analisar, por meio de uma série de indicadores, a evolução da pobreza nos nove estados da região Nordeste entre os anos de 1995 a 2005, expondo os principais atributos que influenciaram na dinâmica observada. De uma maneira geral, observou-se que, embora em 2005 os indicadores de pobreza ainda se encontrassem em patamares alarmantes, houve uma tendência semelhante na sua evolução na região – um considerável declínio entre 1995 e 2005 – contudo, com pequenas divergências nas intensidades de comportamento dos diferentes estados. -----------------------------------------------All over the world, an ample consensus exists between scientists, political, researchers and intellectuals that poverty reduction should be seen as one of the public policies priorities. Therefore, poverty level mensuration becomes the target of an intense debate, when it is necessary firstly to identify where poverty is located to have, afterwards, conditions of combatting it. Nowadays, in Brazil, this concern is more evident when the analyses focus the economical space of the Northeast, because this region is considered the poorest of the country. At the same time, it is known that, starting from middles of 1994, a new political reality was imposed to the country resulting in several consequences for the national population and, automatically, the Northeaster population too. In this sense, this article has as general objective to measure and analyze, through several indicators, poverty evolution in the nine states of the Brazilian Northeast Region among the 1995 and 2005, exposing the main attributes that influenced in the observed dynamics. In general, it was observed that, although in 2005 the poverty indicators were in high levels, there was a similar tendency in the poverty evolution in the region – a considerable decline between 1995 and 2005 – however, with some divergences in the behaviors intensities of different States.Medidas de Pobreza, Nordeste, Políticas Públicas Nacionais, Poverty Measures, Northeast, National Public Politics, Food Security and Poverty,

    Merging black hole binaries with the SEVN code

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    Studying the formation and evolution of black hole binaries (BHBs) is essential for the interpretation of current and forthcoming gravitational wave (GW) detections. We investigate the statistics of BHBs that form from isolated binaries, by means of a new version of the SEVN population-synthesis code. SEVN integrates stellar evolution by interpolation over a grid of stellar evolution tracks. We upgraded SEVN to include binary stellar evolution processes and we used it to evolve a sample of 1.5 x 10(8) binary systems, with metallicity in the range [10(-4); 4 x 10(-2)]. From our simulations, we find that the mass distribution of black holes (BHs) in double compact-object binaries is remarkably similar to the one obtained considering only single stellar evolution. The maximum BH mass we obtain is similar to 30, 45, and 55 M-circle dot at metallicity Z = 2 x 10(-2), 6 x 10(-3), and 10(-4), respectively. A few massive single BHs may also form (less than or similar to 0.1 per cent of the total number of BHs), with mass up to similar to 65, 90, and 145 M-circle dot at Z = 2 x 10(-2), 6 x 10(-3), and 10(-4), respectively. These BHs fall in the mass gap predicted from pair-instability supernovae. We also show that the most massive BHBs are unlikely to merge within a Hubble time. In our simulations, merging BHs like GW151226 and GW170608, form at all metallicities, the high-mass systems (like GW150914, GW170814, and GW170104) originate from metal-poor (Z less than or similar to 6 x 10(-3)) progenitors, whereas GW170729-like systems are hard to form, even at Z = 10(-4). The BHB merger rate in the local Universe obtained from our simulations is similar to 90Gpc(-3)yr(-1), consistent with the rate inferred from LIGO-Virgo data
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