Oxygen and SO2 Consumption Rates in White and Rosé Wines: Relationship with and Effects on Wine Chemical Composition

This Article addresses the study of O2 and SO2 consumption rates of white and rosé wines, their relationship to the initial chemical composition, and their effects on the chemical changes experienced by wine during oxidation. Eight wines were subjected to five consecutive air-saturation cycles. O2 was monitored periodically; SO2, color, and antioxidant indexes were determined after each cycle, and the initial and final compositions of the wines were thoroughly determined. Wines consumed oxygen at progressively decreasing rates. In the last cycles, after a strong decrease, consistent increases of oxygen levels were seen. Oxygen consumption rates were satisfactorily modeled, being proportional to wine copper, quercetin, and kaempherol contents and negatively proportional to cinnamic acids. SO2 consumption rates were highly diverse between wines and were positively related to free SO2, Mn, and pH, among others. In the last saturations, SO2 consumption took place regardless of O2 consumption, implying that SO2 should reduce chemical species oxidized in previous saturations. Some volatile phenols seem to be the end point of radical-mediated oxidation of polyphenols taking place preferably in the first saturation

An assessment of voltammetry on disposable screen printed electrodes to predict wine chemical composition and oxygen consumption rates

The present work aimed at determining the applicability of linear sweep voltammetry coupled to disposable carbon paste electrodes to predict chemical composition and wine oxygen consumption rates (OCR) by PLSmodeling of the voltammetric signal. Voltammetric signals were acquired in a set of 16 red commercial wines. Samples were extensively characterized including SO2, antioxidant indexes, metals and polyphenols measured by HPLC. Wine OCRs were calculated by measuring oxygen consumption under controlled oxidation conditions. PLS-Regression models were calculated to predict chemical variables and wine OCRs from first order difference voltammogram curves. A significant number of fully validated models predicting chemical variables from voltammetric signals were obtained. Interestingly, monomeric and polymerized anthocyanins can be differently predicted from the first and second wave of the first derivative of voltammograms, respectively. This fast, cheap and easy-to-use approach presents an important potential to be used in wineries for rapid wine chemical characterization

The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

This work seeks to understand the kinetics of O2 and SO2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620 nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO2 consumption is favoured by low levels of SO2, by a low availability of free SO2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins

High-Luminosity Large Hadron Collider (HL-LHC): Technical Design Report

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 9000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its instantaneous luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total number of collisions) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require new infrastructures (underground and on surface) and over a decade to implement. The new configuration, known as High Luminosity LHC (HL-LHC), relies on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11–12 Tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 100 metre-long high-power superconducting links with negligible energy dissipation, all of which required several years of dedicated R&D effort on a global international level. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of the HL-LHC

Réduction du bruit large bande des ventilateurs centrifuges pour le CVC

Des dentelures au bord d'attaque ou au bord de fuite ont été utilisées avec un certain succès comme méthode de réduction de bruit sur des profils aérodynamiques. Plus récemment, cette technique a aussi été utilisée pour des ventilateurs hélicoïdes. Cette thèse étend l'application des dentelures sur un ventilateur centrifuge à roue libre. Des résultats précédents sur des profils ont servi à concevoir et fabriquer plusieurs prototypes avec dentelures au bord d'attaque ou au bord de fuite des pales. Des résultats expérimentaux pour les roues avec dentelures au bord d'attaque montrent à débit donné une chute de pression pour la plupart des points de fonctionnement en comparaison du ventilateur de base sans dentelures, et inversement une augmentation de la pression aux grands débits. Les dentelures entrainent une réduction du bruit aux moyennes fréquences, mais une augmentation du bruit en haute fréquence. Sur le niveau de bruit global, ceci se traduit par une légère augmentation du bruit pour la plupart des géométries et points de fonctionnement. Les dentelures au bord de fuite réduisent le bruit pour la plupart des points de fonctionnement. Cette réduction se produit sur tout le spectre, sans augmentation du bruit à haute fréquence. De plus, on a constaté également la suppression d'un bruit quasi-tonal de très forte amplitude à haute fréquence et petit débit. Un modèle analytique de prévision du bruit du ventilateur de base, sans dentelures, a aussi été développé. Celui-ci est basé sur le modèle d'Amiet, en prenant en compte les bruits de bord d'attaque et de bord de fuite des pales, mais aussi le bruit de l'extrémité des flasques. Les résultats montrent que le bruit de bord de fuite est dominant par rapport au bruit de bord d'attaque. En outre, les flasques ne contribuent pas au bruit global du ventilateur. La comparaison entre la prévision analytique et les résultats expérimentaux montre une sous-estimation du bruit à toutes les fréquences. Il y a plusieurs raisons qui pourraient expliquer cela. D'autres sources que le bruit de bord d'attaque et le bruit de bord de fuite peuvent contribuer au bruit du ventilateur. De plus, les modèles analytiques et empiriques utilisés pour obtenir les données d'entrée du modèle acoustique ajoutent une incertitude à la prévision.Leading-edge or trailing-edge serrations have been used with some success as a noise-reduction technique applied to fixed airfoils in wind-tunnels. More recently, this method has also been used on axial fans. This thesis extends the application of serrations to a centrifugal plenum fan. Using previous results from airfoils, several prototypes of impellers with trailing edge or leading edge serrations on the blades were designed and manufactured. Experimental results for the impellers with leading edge serrations showed a pressure drop for most of the operating points with respect to the baseline unserrated configuration, and conversely a pressure increase at high flowrate. Serrations yielded a noise reduction at mid frequencies but increased the noise at high frequencies. As a consequence, the overall sound power level slightly increases at most of the serration geometries and operating points. Trailing edge serrations have reduced noise for most operating points. The broadband noise reduction has been measured over the whole spectrum, with no noise increase at high frequency. Furthermore, the suppression of a nearly-tonal high-frequency peak of very large amplitude has also been reported at low flowrate. An analytical model to predict the noise of the baseline unserrated impeller has also been developed. It is based on Amiet's model and accounts for sources on the trailing edge and the leading edge of the blades, as well as the outer edges of the front and back plates. The results of the prediction show that trailing edge noise dominates over leading edge noise. Furthermore, the edges of the plates do not contribute to the fan noise. The comparison of the analytical prediction with experimental results shows a strong underprediction whatever the frequency. There are several possible reasons behind this. First, other noise sources apart from trailing edge and leading edge noise may be present. Furthermore, the use of analytical and empirical models to predict the input data of the acoustic model also adds incertitude to the predictio

Réduction du bruit large bande des ventilateurs centrifuges pour le CVC

Leading-edge or trailing-edge serrations have been used with some success as a noise-reduction technique applied to fixed airfoils in wind-tunnels. More recently, this method has also been used on axial fans. This thesis extends the application of serrations to a centrifugal plenum fan. Using previous results from airfoils, several prototypes of impellers with trailing edge or leading edge serrations on the blades were designed and manufactured. Experimental results for the impellers with leading edge serrations showed a pressure drop for most of the operating points with respect to the baseline unserrated configuration, and conversely a pressure increase at high flowrate. Serrations yielded a noise reduction at mid frequencies but increased the noise at high frequencies. As a consequence, the overall sound power level slightly increases at most of the serration geometries and operating points. Trailing edge serrations have reduced noise for most operating points. The broadband noise reduction has been measured over the whole spectrum, with no noise increase at high frequency. Furthermore, the suppression of a nearly-tonal high-frequency peak of very large amplitude has also been reported at low flowrate. An analytical model to predict the noise of the baseline unserrated impeller has also been developed. It is based on Amiet's model and accounts for sources on the trailing edge and the leading edge of the blades, as well as the outer edges of the front and back plates. The results of the prediction show that trailing edge noise dominates over leading edge noise. Furthermore, the edges of the plates do not contribute to the fan noise. The comparison of the analytical prediction with experimental results shows a strong underprediction whatever the frequency. There are several possible reasons behind this. First, other noise sources apart from trailing edge and leading edge noise may be present. Furthermore, the use of analytical and empirical models to predict the input data of the acoustic model also adds incertitude to the predictionDes dentelures au bord d'attaque ou au bord de fuite ont été utilisées avec un certain succès comme méthode de réduction de bruit sur des profils aérodynamiques. Plus récemment, cette technique a aussi été utilisée pour des ventilateurs hélicoïdes. Cette thèse étend l'application des dentelures sur un ventilateur centrifuge à roue libre. Des résultats précédents sur des profils ont servi à concevoir et fabriquer plusieurs prototypes avec dentelures au bord d'attaque ou au bord de fuite des pales. Des résultats expérimentaux pour les roues avec dentelures au bord d'attaque montrent à débit donné une chute de pression pour la plupart des points de fonctionnement en comparaison du ventilateur de base sans dentelures, et inversement une augmentation de la pression aux grands débits. Les dentelures entrainent une réduction du bruit aux moyennes fréquences, mais une augmentation du bruit en haute fréquence. Sur le niveau de bruit global, ceci se traduit par une légère augmentation du bruit pour la plupart des géométries et points de fonctionnement. Les dentelures au bord de fuite réduisent le bruit pour la plupart des points de fonctionnement. Cette réduction se produit sur tout le spectre, sans augmentation du bruit à haute fréquence. De plus, on a constaté également la suppression d'un bruit quasi-tonal de très forte amplitude à haute fréquence et petit débit. Un modèle analytique de prévision du bruit du ventilateur de base, sans dentelures, a aussi été développé. Celui-ci est basé sur le modèle d'Amiet, en prenant en compte les bruits de bord d'attaque et de bord de fuite des pales, mais aussi le bruit de l'extrémité des flasques. Les résultats montrent que le bruit de bord de fuite est dominant par rapport au bruit de bord d'attaque. En outre, les flasques ne contribuent pas au bruit global du ventilateur. La comparaison entre la prévision analytique et les résultats expérimentaux montre une sous-estimation du bruit à toutes les fréquences. Il y a plusieurs raisons qui pourraient expliquer cela. D'autres sources que le bruit de bord d'attaque et le bruit de bord de fuite peuvent contribuer au bruit du ventilateur. De plus, les modèles analytiques et empiriques utilisés pour obtenir les données d'entrée du modèle acoustique ajoutent une incertitude à la prévision

Réduction du bruit large bande des ventilateurs centrifuges pour le CVC

Leading-edge or trailing-edge serrations have been used with some success as a noise-reduction technique applied to fixed airfoils in wind-tunnels. More recently, this method has also been used on axial fans. This thesis extends the application of serrations to a centrifugal plenum fan. Using previous results from airfoils, several prototypes of impellers with trailing edge or leading edge serrations on the blades were designed and manufactured. Experimental results for the impellers with leading edge serrations showed a pressure drop for most of the operating points with respect to the baseline unserrated configuration, and conversely a pressure increase at high flowrate. Serrations yielded a noise reduction at mid frequencies but increased the noise at high frequencies. As a consequence, the overall sound power level slightly increases at most of the serration geometries and operating points. Trailing edge serrations have reduced noise for most operating points. The broadband noise reduction has been measured over the whole spectrum, with no noise increase at high frequency. Furthermore, the suppression of a nearly-tonal high-frequency peak of very large amplitude has also been reported at low flowrate. An analytical model to predict the noise of the baseline unserrated impeller has also been developed. It is based on Amiet's model and accounts for sources on the trailing edge and the leading edge of the blades, as well as the outer edges of the front and back plates. The results of the prediction show that trailing edge noise dominates over leading edge noise. Furthermore, the edges of the plates do not contribute to the fan noise. The comparison of the analytical prediction with experimental results shows a strong underprediction whatever the frequency. There are several possible reasons behind this. First, other noise sources apart from trailing edge and leading edge noise may be present. Furthermore, the use of analytical and empirical models to predict the input data of the acoustic model also adds incertitude to the predictionDes dentelures au bord d'attaque ou au bord de fuite ont été utilisées avec un certain succès comme méthode de réduction de bruit sur des profils aérodynamiques. Plus récemment, cette technique a aussi été utilisée pour des ventilateurs hélicoïdes. Cette thèse étend l'application des dentelures sur un ventilateur centrifuge à roue libre. Des résultats précédents sur des profils ont servi à concevoir et fabriquer plusieurs prototypes avec dentelures au bord d'attaque ou au bord de fuite des pales. Des résultats expérimentaux pour les roues avec dentelures au bord d'attaque montrent à débit donné une chute de pression pour la plupart des points de fonctionnement en comparaison du ventilateur de base sans dentelures, et inversement une augmentation de la pression aux grands débits. Les dentelures entrainent une réduction du bruit aux moyennes fréquences, mais une augmentation du bruit en haute fréquence. Sur le niveau de bruit global, ceci se traduit par une légère augmentation du bruit pour la plupart des géométries et points de fonctionnement. Les dentelures au bord de fuite réduisent le bruit pour la plupart des points de fonctionnement. Cette réduction se produit sur tout le spectre, sans augmentation du bruit à haute fréquence. De plus, on a constaté également la suppression d'un bruit quasi-tonal de très forte amplitude à haute fréquence et petit débit. Un modèle analytique de prévision du bruit du ventilateur de base, sans dentelures, a aussi été développé. Celui-ci est basé sur le modèle d'Amiet, en prenant en compte les bruits de bord d'attaque et de bord de fuite des pales, mais aussi le bruit de l'extrémité des flasques. Les résultats montrent que le bruit de bord de fuite est dominant par rapport au bruit de bord d'attaque. En outre, les flasques ne contribuent pas au bruit global du ventilateur. La comparaison entre la prévision analytique et les résultats expérimentaux montre une sous-estimation du bruit à toutes les fréquences. Il y a plusieurs raisons qui pourraient expliquer cela. D'autres sources que le bruit de bord d'attaque et le bruit de bord de fuite peuvent contribuer au bruit du ventilateur. De plus, les modèles analytiques et empiriques utilisés pour obtenir les données d'entrée du modèle acoustique ajoutent une incertitude à la prévision

Experimental investigation of the noise reduction of a plug fan with leading-edge serrations

International audienc

Oxygen Consumption by Red Wines. Part I: Consumption Rates, Relationship with Chemical Composition, and Role of SO\u2082

Fifteen Spanish red wines extensively characterized in terms of SO2, color, antioxidant indexes, metals, and polyphenols were subjected to five consecutive sensor-controlled cycles of air saturation at 25 \ub0C. Within each cycle, O2 consumption rates cannot be interpreted by simple kinetic models. Plots of cumulated consumed O2 made it possible to define a fast and highly wine-dependent initial O2 consumption rate and a second and less variable average O2 consumption rate which remains constant in saturations 2 to 5. Both rates have been satisfactorily modeled, and in both cases they were independent of Fe and SO2 and highly dependent on Cu levels. Average rates were also related to Mn, pH, Folin, protein precipitable proanthocyanidins (PPAs), and polyphenolic profile. Initial rates were strong and negatively correlated to SO2 consumption, indicating that such an initial rate is either controlled by an unknown antioxidant present in some wines or affected by a poor real availability of SO2. Remaining unreacted SO2 is proportional to initial combined SO2 and to final free acetaldehyde