441 research outputs found
Aerodynamic design optimization of wind turbine airfoils under aleatory and epistemic uncertainty
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
A gas chromatography-mass spectrometry-based metabolomic approach for the characterization of goat milk compared with cow milk
In this work, the polar metabolite pool of commercial caprine milk was studied by gas chromatography-mass spectrometry and multivariate statistical data analysis. Experimental data were compared with those of cow milk and the discriminant analysis correctly classified milk. By the same means, differences due to heat treatments (UHT or pasteurization) on milk samples were also investigated. Results of the 2 discriminant analyses were combined, with the aim of finding the discriminant metabolites unique for each class and shared by 2 classes. Valine and glycine were specific to goat milk, talose and malic acid to cow milk, and hydroxyglutaric acid to pasteurized samples. Glucose and fructose were shared by cow milk and UHT-treated samples, whereas ribose was shared by pasteurized and goat milk. Other discriminant variables were not attributed to specific metabolites. Furthermore, with the aim to reduce food fraud, the issue of adulteration of caprine milk by addition of cheaper bovine milk has been also addressed. To this goal, mixtures of goat and cow milk were prepared by adding the latter in a range from 0 to 100% (vol/vol) and studied by multivariate regression analysis. The error in the level of cow milk detectable was approximately 5%. These overall results demonstrated that, through the combined approach of gas chromatography-mass spectrometry and multivariate statistical data analysis, we were able to discriminate between milk typologies on the basis of their polar metabolite profiles and to propose a new analytical method to easily discover food fraud and to protect goat milk uniqueness. The use of appropriate visualization tools improved the interpretation of multivariate model results
Robust aerodynamic design optimization of variable speed wind turbine rotors
Background: Manufacturing and assembly tolerances may cause wind turbine (WT) energy production to differ significantly from nominal design targets. Issue can be alleviated in two ways: A. Reducing tolerances. This may be expensive. B. Developing reliable and computationally affordable robust analysis and design optimization technologies. Robust WT rotor is one yielding minimal variations of aerodynamic performance arising due to errors affecting rotor geometry. Objectives: To develop/demonstrate computational framework for the robust design optimization of WT rotors. Main aim is to 1) maximize expectation and 2) minimize standard deviation of yearly energy production. Highlight computational effectiveness of the Univariate Reduced Quadrature approach to ‘deterministic’ uncertainty propagation. Highlight capabilities of a recently developed multi-level evolution-based optimizer
Lipid Process Markers of Durum Wheat Debranning Fractions
At present, whole grains are usually obtained by adding bran and middlings to refined flours, and this recombination leads to certain variations in the ratio of endosperm, bran and germ, resulting in flours with very different compositional characteristics and rheological properties. Therefore, this study focuses on the identification of specific lipid markers in different debranning fractions of Italian and Canadian durum wheat blends. The by-products obtained from five different debranning levels (3, 6, 9, 12 and 15%) had a high content of monounsaturated fatty acids and a higher concentration of tocopherols and sterols than the corresponding debranned grains. The Italian and Canadian durum wheat samples did not show significant differences in the content of these bioactive lipid compounds. In particular, palmitic acid, oleic acid, tocopherol isomers and total sterols could be useful biomarkers for evaluating the grain-to-tissue ratio in recombined flours
GC-MS Metabolomics and Antifungal Characteristics of Autochthonous Lactobacillus Strains
Lactobacillus strains with the potential of protecting fresh dairy products from spoilage were studied. Metabolism and antifungal activity of different L. plantarum, L. brevis, and L. sakei strains, isolated from Sardinian dairy and meat products, were assessed. The metabolite fingerprint of each strain was obtained by GC-MS and data submitted to multivariate statistical analysis. The discriminant analysis correctly classified samples to the Lactobacillus species and indicated that, with respect to the other species, L. plantarum had higher levels of organic acids, while L. brevis and L. sakei showed higher levels of sugars than L. plantarum. Partial Least Square (PLS) regression correlated the GC-MS metabolites to the antifungal activity (p Lactobacillus strains and indicated that organic acids and oleamide are positively related with this ability. Some of the metabolites identified in this study have been reported to possess health promoting proprieties. These overall results suggest that the GC-MS-based metabolomic approach is a useful tool for the characterization of Lactobacillus strains as biopreservatives
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Aerodynamic analysis of Ampyx’s airborne wind energy system
Besides classical horizontal and vertical axis wind turbines, alternative ways to harvest wind energy are currently being explored. One promising concept is represented by airborne wind energy systems. Different airborne wind energy concepts have been ideated and investigated over the past few decades. The work reported here focuses on the concept being developed by Ampyx Power that basically generates power using a tethered airplane which drives a generator on the ground. The aim of the work reported here is to develop and compare design calculations for such a power plane. In this study a comparison was made between steady and unsteady RANS CFD calculations from SU2 and OpenFOAM. Subsequently, using the data from the CFD calculation two different power prediction models were developed and compared, one using 2D CFD data with the free vortex code AWSM and the other using the same data with a nonlinear lifting line approach to model the power plane in its figure eight flying trajectory. Overall, comparisons show that for all practical angles of attack, as well as a range of flap angles, that 2D CFD results agree extremely well between both solvers. The 3D CFD results show <20% differences on the computed total forces, despite achieving good agreement on the relative force contributions across the power plane. A very good agreement has also been established between the power prediction models
Enzymatic digestion of calf fleshing meat by-products: Antioxidant and anti-tyrosinase activity of protein hydrolysates, and identification of fatty acids
open7noThis research was funded by Italian Ministry of Education, University and Research, National Project Cluster Agrifood SO.FI.A. (SOstenibilità della FIliera Agroalimentare) (2013–2017, Grant Number CTN01_00230_450760).The food waste reduction through an efficient recovery of its valuable building molecules has become an important topic with a positive effect on the economy and the environment. In this work, the revalorization of slaughterhouse calf fleshing meat through its enzymatic hydrolysis is proposed. The proteolytic activity of 11 enzymes was initially screened and the four most efficient enzymes (papain, trypsin, pancreatin, and bromelain) were selected. The molecular profiling of the different protein/peptide fractions by the Linear Trap Quadrupole-OrbiTrap technique showed compositional differences due to the specificity of the enzymes’ cleavage sites. In order to find a potential reuse of these hydrolysates, the analysis of antioxidant and, for the first time on fleshing meat hydrolysates, of anti-tyrosinase activities, was performed. Papain-digested samples were those showing the highest inhibition activity of tyrosinase enzyme (55.6%) as well as the highest antioxidant activity (3.52 g TEAC/L). In addition, the composition analysis of the lipid fraction was performed. The mono-unsaturated fatty acids resulted to be the most abundant lipid in all the samples with the exception of pancreatin-treated hydrolysates in which poly-unsaturated fatty acids were predominant. The present results seemed to support a possible valorization of isolated fractions from calf fleshing by-products, as food or feed ingredients, by the implementation of fraction isolation within the meat-processing pipeline.openTedeschi T.; Anzani C.; Ferri M.; Marzocchi S.; Caboni M.F.; Monari S.; Tassoni A.Tedeschi T.; Anzani C.; Ferri M.; Marzocchi S.; Caboni M.F.; Monari S.; Tassoni A
PRELIMINARY CHEMICAL CHARACTERIZATION OF TUNISIN MONOVARIETAL VIRGIN OLIVE OILS AND COMPARISON WITH SICILIAN ONES.
Work was carried out on the characterization of monovarietal virgin olive oils (VOO)
from Tunisia and Sicily (Italy). The two main Tunisian VOO (cvv. Ch\ue9toui of the North and
cv. Chemlali grown in the Center and some regions of the South) and three principal
Sicilian VOO (cvv. Nocellara del Belice, Biancolilla and Cerasuola) were studied.
Moreover, the Ch\ue9toui oils were tested in a rain-fed control and an irrigation regime. All
olive samples were picked at three different stages of ripeness. Analyses of major
components (fatty acids and triacylglycerols) and minor ones (squalene, tocopherols
and phenolic compounds) were carried out. Ch\ue9toui oils had a higher level of phenolic
compounds followed by Chemlali. Generally, in the Sicilian oils these natural antioxidant
contents were lower. These preliminary results indicate that it was possible to
classify the Tunisian and Sicilian oils tested in their original growing area based on their
chemical composition
Cryopreservation of hazelnut (Corylus avellana l.) axillary buds from in vitro shoots using the droplet vitrification method
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
New diagnostic possibilities in systemic neonatal infections: metabolomics
Systemic neonatal infection is a serious complication in preterm and term infants and is defined as a complex clinical syndrome caused by bacteria, fungi and virus. Sepsis remains among the leading causes of death in both developed and underdeveloped countries above all in the neonatal period. Earlier diagnosis may offer the ability to initiate treatment to prevent adverse outcomes. There have been many studies on various diagnostic haematological markers like acute phase reactants, C-reactive protein, procalcitonin, interleukins and presepsin. However, there is still no single test that satisfies the criteria as being the ideal marker for the early diagnosis of neonatal sepsis. In this regard, metabolomic analysis seems to be a promising method for determining metabolic variations correlated with systemic neonatal infection
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