Actuator disc methods for open propellers: assessments of numerical methods

The paper describes the assessment of two different actuator disc models as applied to the flow around open propellers. The first method is based on a semi-analytical approach returning the solution for the nonlinear differential equation governing the axisymmetric, steady, inviscid and incompressible flow around an actuator disc. Despite its low computational cost, the method does not require simplifying assumptions regarding the shape of the slipstream, e.g. the wake contraction is not disregarded or prescribed in advance. Moreover, the presence of a tangential velocity in the wake as well as the spanwise variation of the load are taken into account. The second one is a commonly used procedure based on CFD techniques in which the effects of the propeller are synthetically described through a set of body forces distributed over the disc surface. Both methods avoid the difficulties and the computational costs associated with the resolution of the propeller blades geometrical details. The comparison is based on an in-depth error analysis of the two procedures which results in a set of reference data with controlled accuracy. An excellent agreement has been documented between the two methods while the computational complexity is obviously very different. Among other things the comparison is also aimed at verifying the accuracy of the semi-analytical approach at each point of the computational domain and at quantifying the effect of the errors embodied in the two methods on the quality of the solution, both in terms of global and local performance parameters. Furthermore, the paper provides a set of reference solutions with controlled accuracy that could be used for the verification of new and existing computational methods. Finally, the computational cost of the semi-analytical model is quantified, thus providing a valuable information to designers who need to select a cost effective and reliable analysis tool

Reflexiones periféricas sobre las disyuntivas identitarias de una Europa en crisis: oscilaciones de un sueño paneuropeo cargado de una compleja vanidad

La Europa moderna, se ha erigido como centro irradiador de cultura y valores universales, en representación de la civilización occidental. Los enfoques eurocéntricos han generado el diseño hegemónico de construcciones sociales que han permitido construir una idea de pertenencia a pesar de la falta de unidad al interior de un continente profundamente diverso, en donde múltiples identidades -locales, nacionales y regionales - entran sistemáticamente en fricción. Así, mientras, por un lado, el viejo continente se halla atravesando un proceso transitivo producto de una nueva crisis multidimensional, por otro, aún puede apreciarse una cuota de vanidad en ciertos sectores -cuya versión extrema aquí se ha denominado Euronarcisimo- respecto del rol civilizatorio que aquel debe desempeñar en el actual sistema global. En ese marco, el presente artículo surgido de las experticias vividas en el viejo continente por estos autores, analiza la actual coyuntura europea, rescatando algunas de las principales contradicciones identitarias que emergen y se profundizan mientras Europa piensa su nuevo rol en un mundo en cambioModern Europe has emerged as a radiating center of culture and universal values, representing Western civilization. Eurocentric approaches have generated the design of hegemonic social constructs that have allowed it to build a sense of belonging despite the lack of unity within a deeply diverse continent, where multiple local, regional and national identities, are in friction systematically. So, on the one hand, the old continent is undergoing a transitive process product of a new multidimensional crisis, on the other, can still be seen a vanity in certain sectors - extreme version of which has been termed here Euronarcisimo - about civilization role that it be should play in the current global system. In this context, this paper that emerged from the expertise gained in the old continent by these authors, analyzes the current European situation, some of major identity contradictions that emerge and deepened as Europe rethinks his new role on a changing world.Comini, Nicolás M. Licenciado en Relaciones Internacionales (Universidad del Salvador); Becario doctoral del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y docente titular de cátedra de Política Internacional Contemporánea y Teoría de las Relaciones Internacionales II y III (Universidad del Salvador)Bontempo, Tomas. Licenciado en Relaciones Internacionales (Universidad del Salvador); Docente adjunto e investigador de la cátedra de Teoría de las Relaciones Internacionales II y III (IDICSO/USAL) y Maestrando en Integración Latinoamericana (Universidad Nacional de Tres de Febrero - UNTREF

Reflexiones periféricas sobre las disyuntivas identitarias de una Europa en crisis: oscilaciones de un sueño paneuropeo cargado de una compleja vanidad

La Europa moderna, se ha erigido como centro irradiador de cultura y valores universales, en representación de la civilización occidental. Los enfoques eurocéntricos han generado el diseño hegemónico de construcciones sociales que han permitido construir una idea de pertenencia a pesar de la falta de unidad al interior de un continente profundamente diverso, en donde múltiples identidades -locales, nacionales y regionales - entran sistemáticamente en fricción. Así, mientras, por un lado, el viejo continente se halla atravesando un proceso transitivo producto de una nueva crisis multidimensional, por otro, aún puede apreciarse una cuota de vanidad en ciertos sectores -cuya versión extrema aquí se ha denominado Euronarcisimo- respecto del rol civilizatorio que aquel debe desempeñar en el actual sistema global. En ese marco, el presente artículo surgido de las experticias vividas en el viejo continente por estos autores, analiza la actual coyuntura europea, rescatando algunas de las principales contradicciones identitarias que emergen y se profundizan mientras Europa piensa su nuevo rol en un mundo en cambioModern Europe has emerged as a radiating center of culture and universal values, representing Western civilization. Eurocentric approaches have generated the design of hegemonic social constructs that have allowed it to build a sense of belonging despite the lack of unity within a deeply diverse continent, where multiple local, regional and national identities, are in friction systematically. So, on the one hand, the old continent is undergoing a transitive process product of a new multidimensional crisis, on the other, can still be seen a vanity in certain sectors - extreme version of which has been termed here Euronarcisimo - about civilization role that it be should play in the current global system. In this context, this paper that emerged from the expertise gained in the old continent by these authors, analyzes the current European situation, some of major identity contradictions that emerge and deepened as Europe rethinks his new role on a changing world.Comini, Nicolás M. Licenciado en Relaciones Internacionales (Universidad del Salvador); Becario doctoral del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y docente titular de cátedra de Política Internacional Contemporánea y Teoría de las Relaciones Internacionales II y III (Universidad del Salvador)Bontempo, Tomas. Licenciado en Relaciones Internacionales (Universidad del Salvador); Docente adjunto e investigador de la cátedra de Teoría de las Relaciones Internacionales II y III (IDICSO/USAL) y Maestrando en Integración Latinoamericana (Universidad Nacional de Tres de Febrero - UNTREF

Reseña de De Paz Trueba, Yolanda (2019). Infancia, pobreza y asistencia. Argentina, primera mitad del siglo XX. Rosario: Prohistoria

Nota bibliográfica del libro Infancia, Pobreza y asistencia. Argentina, primera mitad del siglo XX. Este trabajo, compilado por Yolanda de Paz Trueba, muestra, por un lado, el interés de largo aliento que los autores han demostrado en estas temáticas y; por otro lado, el resultado de las investigaciones que tuvieron lugar en el marco del proyecto “Circulación de niños y asilos para huérfanos. El centro y sureste de la provincia de Buenos Aires entre 1890 y 1920 (Pict 2086/2014) del cual de Paz Trueba es su directora. Así, este libro pretende observar la asistencia social en la primera mitad del siglo veinte no sólo desde el ángulo estatal sino también, desde el menos explorado, de las prácticas y estrategias desarrolladas por aquellos que solicitaban ser “beneficiados” y de la relación dinámica que se establecía entre las instituciones y actores con los que interactuaban

Evaluation of photosensitive films for light measurements in the fruiting zone of grapevine canopies

The potential influence of fruit exposure and canopy manipulations on grape berry composition is well recognized. However, a simple and low cost method for quantifying the amount of light reaching the fruiting zone is lacking. The objective of the present study was to test the application of a commercial system of photosensitive azo-dye coated plastic films for characterizing light conditions within grapevine canopies. The fading rates of three films of differing light sensitivity were initially monitored in a fully exposed position, and these all showed a linear or near linear relationship with radiation measured by an adjacent global solar radiation sensor. When mounted in the fruiting zone of a vertically trained cool climate 'Riesling' vineyard for two periods following early and late leaf removal treatments, the films were able to quantify the change in light exposure within the fruiting zone. Total radiation values calculated using an on-site calibration or manufacturer´s equation were comparable. While some consideration is needed with regard to the choice of film sensitivity and positioning within the canopy, these initial evaluations suggest these light sensitive films can provide a simple and accurate method for characterizing light conditions and quantifying cumulative radiation within the fruiting zone

NMR profiling of grape musts from some Italian regions

With wine fraud, being a widespread problem [1], the need for more sophisticated and precise analytical methods of its detection remains ever persistent. Nuclear magnetic resonance (NMR) spectroscopy has been widely used for analysis of wine in recent years [2,3], but wine musts were much less studied; in fact, only one paper dealt with the NMR spectra of actual musts [4]. Difficulties arise mostly because grape musts are “live” objects, which undergo rapid fermentation at room temperature, if not inhibited either by freezing or chemical preservative; but even such measures are not sufficient to halt it completely [5]. We have investigated over 300 samples of grape must from 17 of 20 different Italian regions using 1H NMR spectroscopy with water signal suppression, postprocessing in the MatLab software with dynamic alignment [6] and optimized binning [7] to alleviate the effect of fermentation on the chemical shifts of mobile protons. After that, multivariate statistics was performed with techniques such as PCA, PLS-DA and OPLS-DA with respect to various group parameters such as regions, vitivinicultural zones, harvest periods and grape varieties. Advantages and drawbacks of each method were addresse

Determination of regulated and emerging mycotoxins in organic and conventional gluten-free flours by LC-MS/MS

Gluten-free cereal products have grown in popularity in recent years as they are perceived as “healthier” alternatives and can be safely consumed by celiac patients, and people with gluten intolerance or wheat allergies. Molds that produce mycotoxins contaminate cereal crops, posing a threat to global food security. Maximum levels have been set for certain mycotoxins in cereal flours; however, little is known about the levels of emerging mycotoxins in these flours. The aim of this study was to develop an efficient, sensitive, and selective method for the detection of four emerging (beauvericin and enniatins A1, B, and B1) and three regulated (aflatoxin B1, zearalenone, and deoxynivalenol) mycotoxins in gluten-free flours. Ultrasound-assisted matrix solid-phase dispersion was used in the extraction of these mycotoxins from flour samples. The validated method was utilized for the LC-MS/MS analysis of conventional and organic wholegrain oat and rice flours. Six of the seven target mycotoxins were detected in these samples. Multi-mycotoxin contamination was found in all flour types, particularly in conventional wholegrain oat flour. Despite the low detection frequency in rice flour, one sample was found to contain zearalenone at a concentration of 83.2 µg/kg, which was higher than the level set by the European Commission for cereal flours. The emerging mycotoxins had the highest detection frequencies; enniatin B was present in 53% of the samples at a maximum concentration of 56 µg/kg, followed by enniatin B1 and beauvericin, which were detected in 46% of the samples, and at levels reaching 21 µg/kg and 10 µg/kg, respectively. These results highlight the need to improve the current knowledge and regulations on the presence of mycotoxins, particularly emerging ones, in gluten-free flours and cereal-based product