484 research outputs found

    Aerodynamic design optimization of wind turbine airfoils under aleatory and epistemic uncertainty

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    This paper presents different approaches to optimize wind turbine airfoils in an uncertain scenario. The approaches are specifically applied to the aerodynamic design optimization of a wind turbine airfoil accounting for the uncertainty in setting up the XFOIL's NCRIT constant: a parameter that is considered affected by a chain of aleatory and epistemic uncertainty. Subject to a set of aerodynamic and structural constraints, the uncertain response of the airfoil is optimized by means of both probability- and imprecise probability-based approaches. These solutions are compared with a reference airfoil optimized with a conventional design approach, in which the treatment of uncertainty is carried out in a simplistic fashion. Once evaluated in the probabilistic scenario, the airfoil designed with the conventional approach still achieves the largest aerodynamic efficiency mean. This airfoil is however affected by the largest performance sensitivity to NCRIT variations. The airfoils optimized by means of uncertainty-based approaches instead achieve larger performance robustness and reliability than the airfoil optimized with the conventional approach

    Education and Sustainability: The Case of Emotions Park

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    Firms working in the third millennium have to face the challenge of being more sustainable. The complexity and the multidisciplinary nature of sustainability also requires new and specific knowledge. This means the necessity of a critical rethinking of the education system in the way to provide the cognitive tools and applications needed for new generations to address environmental, economic, and social challenges. In this perspective, the role of the school it is crucial, above all, to encourage attention to include sustainability as a theme on educational programs, focusing on the promotion of its multiple dimensions. Interdisciplinary sustainability programs are emerging globally, but little is known about the learning in these educational contexts. Therefore, the current research explores training modules used in the activities of a park to verify how students can receive a sustainable education from primary school; whether and in which way education can be a driver for the promotion of sustainable development; and whether it is effective to insert eco-activities such as eco-games, eco-campus, and eco-sports in the training modules from primary school onwards. For this purpose, the paper employed a single case study approach using the Emotions Park as a teaching plan. In particular, game and sports constantly accompany the training process by creating interdisciplinary links with different study subjects (e.g., civic education, environmental education, communication). Through the eco-activities, an innovative way to promote environmental and sustainability education was explored as a training model. Outdoor play, observation, and stimulation of the senses have proved powerful learning tools, and key to the acquisition of skills. Research data were collected observing the behavior of a sample of 22 participants and through face-to-face semi-structured interviews with educators, employee and students. The empirical observation suggests that inserting the sustainability principles as a topic in didactic programs provides the cognitive tools and applications needed for the new generations to address environmental, economic, and social challenges

    Tandem Baeyer–Villiger/Wittig/oxa-Michael addition: One-step to 5-substituted γ-lactones

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    The results reported in this study provide a practical protocol for the construction, in one single step of synthetically important γ-lactones in good yields starting from α-hydroxy cyclobutanone, H2O2 and several stabilized phosphonium ylides. Our synthetic strategy relies on a tandem Baeyer–Villiger oxidation/Wittig reaction/oxa-Michael addition

    Growth of monolayer graphene on 8deg off-axis 4H-SiC (000-1) substrates with application to quantum transport devices

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    Using high temperature annealing conditions with a graphite cap covering the C-face of an 8deg off-axis 4H-SiC sample, large and homogeneous single epitaxial graphene layers have been grown. Raman spectroscopy shows evidence of the almost free-standing character of these monolayer graphene sheets, which was confirmed by magneto-transport measurements. We find a moderate p-type doping, high carrier mobility and half integer Quantum Hall effect typical of high quality graphene samples. This opens the way to a fully compatible integration of graphene with SiC devices on the wafers that constitute the standard in today's SiC industry.Comment: 11 pages, 4 figures , Submitted in AP

    Cryopreservation of hazelnut (Corylus avellana l.) axillary buds from in vitro shoots using the droplet vitrification method

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    Cryopreservation by droplet vitrification was applied to hazelnut (Corylus avellana L.). axillary buds of the Italian cultivated variety Tonda Gentile Romana, which were collected from in vitro growing shoots, immersed in ice cooled PVS2 or PVS3 for 60 or 90 min, then transferred to a droplet of vitrification solution, placed on a strip of aluminium foil, and plunged into liquid nitrogen (LN). Additionally, the effect on the recovery of the mother plant after cryopreservation was evaluated, following a cold pre-treatment at 4â—¦C for 3 months. The highest regrowth percentage (56.7%) was obtained after applying PVS3 for 60 min, while the application of PVS2 for the same amount of time reduced regrowth to 41.5%. Increasing the exposure to vitrification solutions to 90 min reduced regrowth to 43.3% when PVS3 was applied, and 35.6% if PVS2 was used. The cold pre-treatment on the mother plant did not significantly improve overall regrowth. The cryopreservation process did not decline the rooting ability of the recovered shoot

    Mechanochemistry Frees Thiourea Dioxide (TDO) from the ‘Veils’ of Solvent, Exposing All Its Reactivity

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    The synthesis of nitrogen-based heterocycles has always been considered essential in developing pharmaceuticals in medicine and agriculture. This explains why various synthetic approaches have been proposed in recent decades. However performing as methods, they often imply harsh conditions or the employment of toxic solvents and dangerous reagents. Mechanochemistry is undoubtedly one of the most promising technologies currently used for reducing any possible environmental impact, addressing the worldwide interest in counteracting environmental pollution. Following this line, we propose a new mechanochemical protocol for synthesizing various heterocyclic classes by exploiting thiourea dioxide (TDO)'s reducing proprieties and electrophilic nature. Simultaneously exploiting the low cost of a component of the textile industry such as TDO and all the advantages brought by a green technique such as mechanochemistry, we plot a route towards a more sustainable and eco-friendly methodology for preparing heterocyclic moieties

    Comparison of predictive and descriptive models in order to plan the monitoring and research on the rock partridge (Alectoris graeca) in the North Eastern Alps

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    Within the implementation of the Management Plan for the Alpi Carniche region (SPA IT3321001, SCI IT3320001, SCI IT3320002, SCI IT3320003, SCI IT3320004) and the realization of the monitoring plan referred to art. 8 of RL No. 7/2008 (Friuli Venezia Giulia) some predictive and descriptive models for the presence and abundance of rock partridge Alectoris graeca saxatilis have been developed and tested. During 2010 the monitoring plan has been carried out during the spring (play-back censuses) and the summer (pointing dog censuses) in 10 sample areas to assess the presence, abundance and reproductive success of the species. These areas have been identified through expert knowledge and predictive models developed by the superimposition on regional UTM 1x1 kilometer grid quadrants of some CORINE Biotopes habitat parameters (open vegetation coverage >50% and open + transitional vegetation coverage >80%) and slope (>10%) and elevation (1000-2200 m above sea level), subsequently ranked from 0 to 4 for a suitability index. The census results related to UTM quadrants (n = 46, 40% with the presence of partridges) and buffer areas (100 meters of radius) created from the locations of the observed animals and the transect points of the censuses (n = 89) have been described by linear selection models that contain habitat classes from the Habitat Map of Friuli Venezia Giulia (Map of the Nature at the scale 1:50.000, ISPRA 2009) and morphological characteristics such as slope, elevation and aspect. The descriptive models have selected different variables according to the season (reproductive and post-reproductive), identifying the presence of Eastern Alpine calcicolous larch with moorland as one of the most important variables to define habitat suitability. Moreover, the descriptive models that use the lesser spatial scale (100 m buffer) seemed to describe better the presence and abundance of this species. The predictive models however were inappropriate to describe the presence of this species and should be used with caution to plan the monitoring activities. The research was supported by the Friuli Venezia Giulia Autonomous Region

    Presence and distribution of the brown bear (Ursus arctos) in Friuli Venezia Giulia, from 2004 to 2011, through the non-invasive genetic monitoring ad conservation implications

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    After having disappeared at the beginning of 1900, the brown bear has started in a late 1960s a slow process of recolonization of the north-eastern Alps, through an expansion of Dinaric population. At the end of the 1990s the University of Udine began the occasional monitoring of the species and from 2004 non-invasive genetic monitoring became systematic. In the last 8 years 217 hair traps have been activated in the region to monitore: Natisone Valleys, the Julian and Carnic Alps and Prealps. Twenty-six hair traps were monitored in all years, whereas 40 were observed only in 2004, 2007 and 2011. The 26 hair traps constantly monitored from 2004 to 2011 showed 17% of average success of hair’s collecting (brown bear samples collected/day control: BBSD). The 40 hair traps, monitored in the window period, showed 12% of BBSD. The BBSD value varied in relation to both season (highest in spring) and year, with a dramatic decline from 2008, and interaction between year and area. From 2004, 13 genotypes, through systematic hair traps monitoring, were identified, while only 2 genotypes were sampled opportunistically. It was observed a high turnover of the genotypes: only 7 genotypes were sampled for more than 2 years (47% of total), 4 genotypes (27% of the total) were sampled for 3 years or more. The annual attendance of bear have been constant from 2004 to 2007, with 5-6 genotypes present every year. In the period between 2008 and 2010 there was a drastic decrease in the successful collection at the hair traps, with and average of 1-2 animals genotyped per year. However, opportunistic samples have increased in the recent times, probably due to the arrivals of 3 genotypes from Trentino (KJ2G2 in 2009 and DG2 and MJ4 in 2011). The year 2011 showed a further increase in the presence of bears with 5 animals genotyped in Friuli Venezia Giulia. Three of these animals belonged to the Slovenian population, while the other 2 genotypes were from the Trentino population. The results seem to confirm the exchange of some individuals between the Dinaric and central alpine population. As an example, the dinaric bear M5 was genotyped in Friuli Venezia Giulia in 2008 and then sampled in 2009 and captured in 2010 in Trentino and finally slot in Slovenia in 2011. The distribution in the alpine and prealpine areas has changed year by year: from the 2004 to 2007 the Natisone Valley and the Julian prealpine areas along the border with Slovenia were the areas more used, whilst from 2009 there was an apparent higher presence of bears in the Carnian Prealps and Alps, and in the Julian Alps. This shift could be due to human disturbance (i.e hunting management), control of the species carried out in neighbouring Slovenia, with a decreasing of immigrant from dinaric populations, and new immigration of bears from the central Alps. The present work has highlighted the necessity for a trans-regional and cross-border management of the species, especially in consideration to the population control applied in Slovenia, which seem to limit the Dinaric population expansion in the Alps, and furthermore the philopatry behaviour of bear females, which implies the absence of females in Friuli Venezia Giulia and induces a movement bach to Slovenia (at least 3 bears genotyped in Italy were shot in Slovenia). All these elements seem to exert important limitations to the consolidation and stabilization of the population of brown bears in north-eastern Alps. From the methodological point of view the protocol of systematic non-invasive genetic monitoring, shared at the trans-regional and trans-boundary level, is fundamental to monitore the dynamics and distribution of bear; the protocol should follow a systematic experimental design and should be integrated with a efficient opportunistic data collection
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