5,565 research outputs found

    Integrated system to perform surrogate based aerodynamic optimisation for high-lift airfoil

    Get PDF
    This work deals with the aerodynamics optimisation of a generic two-dimensional three element high-lift configuration. Although the high-lift system is applied only during take-off and landing in the low speed phase of the flight the cost efficiency of the airplane is strongly influenced by it [1]. The ultimate goal of an aircraft high lift system design team is to define the simplest configuration which, for prescribed constraints, will meet the take-off, climb, and landing requirements usually expressed in terms of maximum L/D and/or maximum CL. The ability of the calculation method to accurately predict changes in objective function value when gaps, overlaps and element deflections are varied is therefore critical. Despite advances in computer capacity, the enormous computational cost of running complex engineering simulations makes it impractical to rely exclusively on simulation for the purpose of design optimisation. To cut down the cost, surrogate models, also known as metamodels, are constructed from and then used in place of the actual simulation models. This work outlines the development of integrated systems to perform aerodynamics multi-objective optimisation for a three-element airfoil test case in high lift configuration, making use of surrogate models available in MACROS Generic Tools, which has been integrated in our design tool. Different metamodeling techniques have been compared based on multiple performance criteria. With MACROS is possible performing either optimisation of the model built with predefined training sample (GSO) or Iterative Surrogate-Based Optimization (SBO). In this first case the model is build independent from the optimisation and then use it as a black box in the optimisation process. In the second case is needed to provide the possibility to call CFD code from the optimisation process, and there is no need to build any model, it is being built internally during the optimisation process. Both approaches have been applied. A detailed analysis of the integrated design system, the methods as well as th

    The root towards more circularized animal production systems: From animal to territorial metabolism

    Get PDF
    This paper deals with a relevant topic in the literature on sustainable management of animal farms, concerning the transition towards circular methods of animal production. The paper aims to put forward an original analytical multilevel perspective overlapping different dimensions at either micro, meso, and macro level. Starting from the Malthusian analysis on depletion of natural resources, with risks of the fragility of the natural and economic systems, the paper points out the importance of moving away from intensive methods of production, by adopting more circularized approaches based on resources efficiency. The application of circular economy approaches to animal production is theorized through the concept of territorial metabolism involving not only internal resources (at the animal farm level) but also territorial resources. The paper underlines the critical points of the transition, which is labeled as a socio-technical transition in that it involves not only technical issues but also social aspects. Critical points are addressed through consumers\u2019 acceptance of products drawn on circular approaches and political support to transition, through political tools which are boosted in recent documents of the European Union, like the Green Deal and Farm to Fork strategy

    The root towards more circularized animal production systems: From animal to territorial metabolism

    Get PDF
    This paper deals with a relevant topic in the literature on sustainable management of animal farms, concerning the transition towards circular methods of animal production. The paper aims to put forward an original analytical multilevel perspective overlapping different dimensions at either micro, meso, and macro level. Starting from the Malthusian analysis on depletion of natural resources, with risks of the fragility of the natural and economic systems, the paper points out the importance of moving away from intensive methods of production, by adopting more circularized approaches based on resources efficiency. The application of circular economy approaches to animal production is theorized through the concept of territorial metabolism involving not only internal resources (at the animal farm level) but also territorial resources. The paper underlines the critical points of the transition, which is labeled as a socio-technical transition in that it involves not only technical issues but also social aspects. Critical points are addressed through consumers’ acceptance of products drawn on circular approaches and political support to transition, through political tools which are boosted in recent documents of the European Union, like the Green Deal and Farm to Fork strategy

    Simplex-Coded BOTDA Sensor Over 120 km SMF with 1 m Spatial Resolution Assisted by Optimized Bidirectional Raman Amplification

    Get PDF
    Bidirectional low-noise Raman amplification and simplex coding based on the return-to-zero modulation format are optimized through numerical simulations for long-range Brillouin optical time-domain analysis sensing. Experimental results are reported on sensing capabilities along 120-km distance with 1-m spatial resolution, and worst-case temperature and strain resolution values of 1.3 °C and 26 με, respectively

    Common fixed points for self-mappings on partial metric spaces

    Get PDF
    In this paper, we prove some results of a common fixed point for two self-mappings on partial metric spaces. Our results generalize some interesting results of Ilic et al. (Appl. Math. Lett. 24:1326-1330, 2011). We conclude with a result of the existence of a fixed point for set-valued mappings in the context of 0-complete partial metric spaces

    Zirconocene-based catalysts for the ethylene-styrene copolymerization: reactivity ratios and reaction mechanism

    Get PDF
    A kinetic study of the ethylene-styrene copolymerization in the presence of rac-(ethylenebis- (1-indenyl)zirconium dichloride activated by MAO shows the peculiar behavior of this catalytic system that is known to produce crystalline nearly alternating copolymers. Some inferences on the monomer- metal interactions are made on the basis of this study. The parallel investigation on the catalyst based on isopropylidene(1-cyclopentadienyl)(9-fluorenyl)zirconium dichloride allows us to produce a stereoregular nearlyalternatingethylene-styrenecopolymeralsowiththiscatalyticsystem. Thesamemaintacticity seems to characterize the copolymers obtained with the C2 and Cs symmetric catalysts in accordance with the generally accepted mechanism of stereocontrol in the 1-alkene polymerizations

    Precision Farming: Barriers of Variable Rate Technology Adoption in Italy

    Get PDF
    Research dealing with the adoption of various precision agriculture technologies has shown that guidance and recording tools are more widespread than reactive ones (such as variable rate technology), with much lower utilization rates in European case studies. This study aims to analyze the propensity to innovate variable rate technologies among young Italian farmers. A cluster analysis was carried out revealing four groups. The first two groups represent non-adopters who think technological innovation is very complex from a technical point of view, as well as not very accessible as capital-intensive technology. The third and fourth groups represent adopters. The third reports an early level of adoption, still considering the cost of access a major barrier to technology implementation. The fourth, on the other hand, shows a more intensive level and considers the lack of institutional support a major limitation. The cluster with the most intensive adoption is characterized by the youngest age group, the farms with the largest size, and a prevalence of female entrepreneurs. The need for management training in day-to-day business operations upon adoption is detected for all groups. This paper identified relevant drivers and barriers in characterizing the adopting farm of variable rate technologies. Results may offer insights to the policy maker to better calibrate support interventions

    Perceptions and preconceptions about chicken and pork meat: A qualitative exploratory study of Argentine consumers in the metropolitan area of Buenos Aires

    Get PDF
    In the past, the Argentine livestock production system was based on the extensive breeding that used pastures. However, technological progress and the use of land for soybean production are leading to a strong intensification of beef production, with a negative impact on the environment. According to FAO data, Argentina has the third highest meat consumption in the world, half of which is beef. A change in diet is a long and difficult process. The first step in favor of the environment could be the replacement of beef with other types of meat that have a lower impact on the environment, such as chicken and pork. The purpose of this study is to understand the causes limiting the preference for these alternatives and to identify useful tools to encourage their consumption. The results show that the interviewed Argentine consumers in the Metropolitan Area of Buenos Aires have preconceptions about these two types of meat, such as the fact that hormones are still used in the chicken production system, that pork has higher cholesterol content than other meats, and that it carries diseases. These products are instead appreciated for their practicality of use, especially when purchased in portions, and they are not only tasty but also cheap

    A Systematic Analysis of the Memory term in Coarse-Grained models: the case of the Markovian Approximation

    Get PDF
    The systematic development of Coarse-Grained (CG) models via the Mori-Zwanzig projector operator formalism requires the explicit description of several terms, including a deterministic drift term, a dissipative memory term and a random fluctuation term. In many applications, the memory and fluctuation terms are related by the fluctuation-dissipation relation and are, in general, more challenging to derive than the drift term. In this work we analyse an approximation of the memory term and propose a rational basis for a data-driven approach to an approximation of the memory and fluctuating terms which can be considered included in the class of the Markovian ones.Comment: 39 pages, 2 Figure
    • …
    corecore