481 research outputs found

    Application of CFD and mass-consistent models for operational wind forecasting

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    In the context of the San Paolo project "Wind monitoring, simulation and forecasting for the smart management and safety of port, urban and territorial system", a computational grid of Livorno City (Italy) and its surroundings at full scale has been constructed for 3D steady-state RANS simulations to be performed by the open-source code OpenFOAM. Field measurements in the same urban area have been scheduled between December 2017 and March 2018 in order to cover the entire winter season, i.e. the windiest one. The CFD results, obtained by initialising the CFD simulations with wind profiles measured through a LiDAR installed in the Port of Livorno, have been validated by means of two ultrasonic three-axial anemometers installed along a narrow canal which is located in the old city centre, about 1.5 km south-westward of the port area

    Local-scale forcing effects on wind flows in an urban environment: Impact of geometrical simplifications

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    Wind flow in urban areas is strongly affected by the urban geometry. In the last decades most of the geometries used to reproduce urban areas, both in wind-tunnel (WT) tests and Computational Fluid Dynamics (CFD) simulations, were simplified compared to reality in order to limit experimental effort and computational costs. However, it is unclear to which extent these geometrical simplifications can affect the reliability of the numerical and experimental results. The goal of this paper is to quantify the deviations caused by geometrical simplifications. The case under study is the district of Livorno city (Italy), called \ue2\u80\u9cQuartiere La Venezia\ue2\u80\u9d. The 3D steady Reynolds-averaged Navier-Stokes (RANS) simulations are solved, first for a single block of the district, then for the whole district. The CFD simulations are validated with WT tests at scale 1:300. Comparisons are made of mean wind velocity profiles between WT tests and CFD simulations, and the agreement is quantified using four validation metrics (FB, NMSE, R and FAC1.3). The results show that the most detailed geometry provides improved performance, especially for wind direction \uce\ub1 = 240\uc2\ub0 (22% difference in terms of FAC1.3)

    Polyphenol characterization and skin-preserving properties of hydroalcoholic flower extract from Himantoglossum robertianum (Orchidaceae)

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    Himantoglossum robertianum (Loisel.) P. Delforge is a Mediterranean orchid whose propagation in vitro has been achieved, making it eligible as a source of bioactive substances. Flowers were analyzed by light and SEM microscopy and used to obtain a polyphenol-rich, hydroalcoholic flower extract (HFE). HFE was characterized for total phenols, flavonoids and proanthocyanidins, and for polyphenol profile by RP-LC-DAD. Antioxidant assays, in vitro collagenase and elastase inhibition, and MTT and cell motility assays on HaCaT keratinocytes were done. Microscopy showed epidermal cells containing anthocyanins in the flower labellum. Flavonoids (flavones and flavan-3-ols) represented the most abundant compounds (42.91%), followed by scopoletin (33.79%), and phenolic acids (23.3%). Antioxidant assays showed strong activities, rating ORAC > FRAP > TEAC > \u3b2-carotene bleaching > DPPH > iron-chelation. Biological assays showed elastase and collagenase inhibition (up to 42% and 78%, respectively), improvement of HaCaT cell viability after treatment with 500 \u3bcM H2O2 (from 30% to 84% of control), and stimulation of cell migration rate up to 210% of control. In summary, HFE counteracted different free radicals, while protective properties were shown by cell-free and cell-based bioassays, suggesting the possible use of H. robertianum flowers for skin-preserving, repair, and anti-aging applications

    Participatory design of robust and sustainable development pathways in the Omo-Turkana river basin

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    Study region: Omo-Turkana Basin, trans-boundary basin between Ethiopia and Kenya (North eastern Africa). Study focus: Significant investments in large dams have been mobilized in the Omo-Turkana basin to expand hydropower and support extensive irrigation projects. Assessing the impacts of these infrastructures, particularly on local stakeholders, constitutes a crucial foundation for socially inclusive as well as environmentally and economically sustainable development. This study showcases the potential of a participatory decision-analytic framework in investigating the impacts of alternative development pathways on competing stakeholders' interests in the OmoTurkana basin to support strategic planning under both current and projected hydroclimatic and socio-economic conditions. The optimal operation of the planned system expansion, including the current and future dam cascade and the irrigation projects, is investigated to provide insights into multisectoral trade-offs. Five main sectors with competing interests are considered: hydropower production, environmental protection, indigenous recession agriculture, fish yield in Lake Turkana, and large-scale commercial irrigated agriculture. New hydrological insights for the region: Results show that the planned infrastructure can negatively impact local stakeholders, particularly in terms of fish yields in Lake Turkana. Still, a potential exists for negotiating operational compromises that are both efficient and socially inclusive. Moreover, even though the performance of the planned infrastructure is expected to decline in the future under changing climate and irrigation demands, this can be mitigated by timely implementing robust solutions triggered by the alterations of streamflows in the northern part of the basin

    Fractal geometry of spin-glass models

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    Stability and diversity are two key properties that living entities share with spin glasses, where they are manifested through the breaking of the phase space into many valleys or local minima connected by saddle points. The topology of the phase space can be conveniently condensed into a tree structure, akin to the biological phylogenetic trees, whose tips are the local minima and internal nodes are the lowest-energy saddles connecting those minima. For the infinite-range Ising spin glass with p-spin interactions, we show that the average size-frequency distribution of saddles obeys a power law wD \sim w^{-D}, where w=w(s) is the number of minima that can be connected through saddle s, and D is the fractal dimension of the phase space

    Comparison of short- and long-term effectiveness of ixekizumab and secukinumab in real-world practice

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    Background: Although secukinumab and ixekizumab both act by inhibiting IL-17A, some scientific evidence suggests that there are differences in efficacy between the two agents. Objective: The aim of this study was to compare the short- and long-term effectiveness of ixekizumab and secukinumab in clinical practice. Methods: A retrospective study was conducted on a cohort of 245 psoriatic patients receiving secukinumab or ixekizumab during the period from September 2016 to December 2019. The proportion of patients achieving PASI75, PASI90, and PASI100 at weeks 12 and 24 was calculated. We recorded the 12- and 24-month drug survival as a measure to assess long-term effectiveness. Results: A higher proportion of patients in the secukinumab group achieved PASI75, 90, and 100 at 12 weeks. The Kaplan-Meier survival curve for any reason of discontinuation showed no differences between the two groups. Instead, the multivariate analysis for ineffectiveness, adjusted for potential confounders, showed a lower drug survival rate in the secukinumab group, with an adjusted HR of 2.57 (95% CI 1.05–6.28, p 0.038). Conclusion: This real-life study demonstrated that ixekizumab and secukinumab are both highly effective in short- and long-term treatment of psoriasis, even though few differences exist concerning speed of action and long-term effectiveness
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