196,149 research outputs found
Passaggio percutaneo in vitro degli idrocarburi policiclici aromatici da creme antiattiniche
No full textCarro con sistema di separazione e trattamento per preservare la qualità delle uve vendemmiate a macchina durante il trasporto in cantina
No full textViene descritto un carro per il trasporto dell’uva raccolta a macchina, modificato per mantenere la qualità del prodotto.
Il sistema si basa sulla separazione sul carro, utilizzato per il trasporto dal campo alla cantina, della componente liquida da quella solida per poter applicare tecniche enologiche differenziate per le due frazioni già prima dell’arrivo in cantina. In particolare il mosto, che rappresenta la parte più pregiata e delicata, viene raccolta in un serbatoio chiuso dove è possibile eseguire interventi quali il raffreddamento, la modifica dell’atmosfera con gas inerti (CO2 o N2) e l’iniezione di prodotti enologici. Inoltre all’arrivo in cantina il mosto può essere immesso direttamente in vasca, senza dover passare nella sequenza operativa normalmente prevista per la lavorazione delle uve (scarico in tramoggia, diraspapigiatura, pressatura, ecc.), che può facilmente causare ossidazione o aumento di fecciosità
Vendemmiatrice con battitore a bassa frequenza con sistema di misura del grado di ammostamento
No full textViene descritta una vendemmiatrici a scuotimento orizzontale allestita con due innovazioni finalizzate a ridurre il danneggiamento dell’uva raccolta: un battitore che opera a bassa frequenza e un sensore per la misura in tempo reale del grado di ammostamento provocato.
Il battitore, oltre ad essere regolabile come altri modelli utilizzati nell’apertura delle due serie di aste contrapposte e nella frequenza del movimento, è studiato per poter modificare la l’ampiezza dell’escursione. Questa regolazione, ottenuta variando idraulicamente la dimensione del manovellismo, consente di adattarsi alle differenti condizioni operative (vitigno, grado di maturazione, ecc.) e di utilizzare la frequenze di battitura più bassa. Come emerso da prove preliminari effettuate nella scorsa vendemmia, l’impiego di una bassa frequenza di battitura favorisce l’integrità dell’uva raccolta, riduce il danneggiamento delle piante e delle strutture di sostegno del vigneto e non penalizza la produttività del lavoro. L’efficienza del battitore viene migliorata anche dalla conformazione e dalla dimensione delle aste, che vengono azionate nei due due punti di fissaggio.
Il sensore per la misura del grado d’ammostamento (mosto che fuoriesce dagli acini a seguito delle sollecitazioni provocate dalla vendemmia meccanica) è uno strumento di controllo che può fornire all’operatore una valutazione in tempo reale del corretto uso della macchina
In vitro percutaneous penetration of polycyclic aromatic hydrocarbons from sunscreen creams
No full textBackground: Dermal exposure to Polycyclic Aromatic Hydrocarbons (PAHs) affects many outdoor workers such as asphalt workers. Usually the use of sunscreen creams is suggested to protect them from UV radiation. However sunscreen could prevent or facilitate dermal absorption of industrial chemicals.
Objectives: The aim of the study was to assess percutaneous penetration of anthracene using 2 different sunscreen creams as vehicle.
Methods: In vitro permeation experiments were carried out using standardized in vitro methods with static diffusion cells. Excised human skin prepared to approximately 350 mm thickness was fixed on the diffusion cells. The receiving phase was a saline solution with 6% PEG 20. The 2 sunscreen creams (one lipophilic and one hydrophilic) were applied uniformly (2mg/cm2) on the skin mounted on the diffusion cell. After 20 minutes, a solution of anthracene and artificial sweat was added. Analysis of anthracene in the receptor samples was carried out by beta counter analyzer (Packard).
Results: Results did not show a percutaneous penetration of anthracene from sunscreen creams while in previous studies in vitro percutaneous penetration of anthracene was demonstrated using the same methodology.
Discussion and Conclusion: The use of sunscreen creams among outdoor workers, would not seem to enhance percutaneous penetration of PAHs. On the contrary it seems to be able to reduce dermal absorption of anthracene in the workplace
In vitro percutaneous penetration of polycyclic aromatic hydrocarbons from sunscreen creams
No full text
Uncertainty quantification analysis of Reynolds-averaged Navier–Stokes simulation of spray swirling jets undergoing vortex breakdown
No full textThe computational fluid dynamics-based design of next-generation aeronautical combustion chambers is challenging due to many geometrical and operational parameters to be optimized and several sources of uncertainty that arise from numerical modeling. The present work highlights the potential benefits of exploiting Bayesian uncertainty quantification at the preliminary design stage. A prototypical configuration of an acetone/air spray swirling jet is investigated through an Eulerian–Lagrangian method under non-reactive conditions. Two direct numerical simulations (DNSs) provide reference data, coping with different vortex breakdown states. Consequently, a set of Reynolds-averaged Navier–Stokes simulations is conducted. Polynomial chaos expansion (PCE) is adopted to propagate the uncertainty associated with the spray dispersion model and the turbulent Schmidt number, delivering confidence intervals and the sensitivity of the output variance to each uncertain input. Consequently, the most significant sources of modeling uncertainty may be identified and eventually removed via a calibration procedure, thus making it possible to carry out a combustion chamber optimization process that is no longer affected by numerical biases. The uncertainty quantification analysis in the current study demonstrates that the spray dispersion model slightly affects the fuel vapor spatial distribution under vortex breakdown flow conditions, compared with the output variance induced by the selection of the turbulent Schmidt number. As a result, additional high-fidelity experimental and numerical campaigns should exclusively address the development of an ad hoc model characterizing the spatial distribution of the latter in the presence of vortex breakdown phenomenology, discarding any effort to improve the spray dispersion formulation
Aircraft Design with Well-to-Wake Optimization Under Uncertainty
No full textExploiting hybrid-electric propulsion in the aviation sector represents one of the possible strategies to tackle the challenging goals imposed by institutions on reducing anthropogenic climate impact. At the same time, Sustainable Aviation Fuels (SAFs) are regarded as the most viable short-term solution to address this requirement. We propose a general aircraft design framework that encompasses the combination of new solutions, i.e., alternative fuels and electric propulsion. The analysis is enriched by including the Well-to-Tank (WTT) processes that precede the aircraft operations, so that the entire fuel life cycle is taken into account. Given the rather unknown technological readiness of SAF production on the large scale, the effects of uncertainties that emerge during the WTT phase on the climate impact and aircraft energy requirement are evaluated by leveraging the potentiality of Uncertainty Quantification (UQ) techniques. The integration of uncertainty propagation with an optimization process enables the assessment of the impact of variance in the WTT chain on optimal design decisions. The presented methodology has been applied to a hybrid SAF/electric regional aircraft architecture with the aim of identifying the optimal hybridization strategy to minimize the overall Well- to-Wake (WTW) climate impact and energy consumption. Results show that the probability distributions of the selected observables are significantly influenced by the technology level of the battery pack. Furthermore, within a specified battery specific energy range, the optimal power management differs depending on the specific objective being pursued
Cytogenetics of Arctic Fish
No full textContributo a Progetto Strategico Artico. Polarnet Technical Report, ISSN 1592-506
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