CFD ANALYSIS OF THE FLOW OVER THE WING EQUIPPED WITH PASSIVE HIGH-LIFT DEVICES

[ES] Proyecto realizado en movilidad en Bucarest. Los objetivos son: - Análisis CFD 2D para mejorar la configuración de un perfil aerodinámico con dispositivos hipersustentadores pasivos de borde de ataque y de salida para despegue. Para ello se emplea el software CONVERGE CFD. - Análisis CFD 3D de un ala con el perfil anterior equipado con los dispositivos hipersustentadores. Para ello se emplea el software FlightStream.[EN] Project carried out in mobility in Bucharest. The objectives are: - 2D CFD analysis to improve an airfoil configuration with passive high-lift leading and trailing edge devices for take-off. CONVERGE CFD software is used for this purpose. - 3D CFD analysis of a wing with the airfoil equipped with the chosen high-lift devices. FlightStream software is used for this purpose.Cid Escobar, PG. (2021). CFD ANALYSIS OF THE FLOW OVER THE WING EQUIPPED WITH PASSIVE HIGH-LIFT DEVICES. Universitat Politècnica de València. http://hdl.handle.net/10251/169214TFG

Cooperative and axiomatic approaches to the knapsack allocation problem

In the knapsack problem a group of agents want to fill a knapsack with several goods. Two issues must be considered. The first is to decide optimally what goods to select for the knapsack. This issue has been studied in many papers in the literature on Operations Research and Management Science. The second issue is to divide the total revenue among the agents. This issue has been studied in only a few papers, and this is one of them. For each knapsack problem we consider three associated cooperative games. One of them (the pessimistic game) has already been considered in the literature. The other two (realistic and optimistic games) are defined in this paper. The pessimistic and realistic games have non-empty cores but the core of the optimistic game could be empty. We then follow the axiomatic approach. We propose two rules: The first is based on the optimal solution of the knapsack problem. The second is the Shapley value of the so called optimistic game. We offer axiomatic characterizations of both rules.Universidad Nacional de San Luis | Ref. 319502Consejo Nacional de Investigaciones Científicas y Técnicas | Ref. PIP 112-200801-00655Agencia Estatal de Investigación | Ref. ECO2017-82241-RXunta de Galicia | Ref. ED431B 2019/3

The full power of the half-power

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGWe use the complex square root to define a very simple homotopic invariant over the non-vanishing functions defined on the circle. As a consequence we provide easy proofs of the plane Brouwer fixed point theorem and the Fundamental Theorem of Algebra. The relation of this new invariant with the winding number and the Brouwer degree will be fully unveiledAgencia Estatal de Investigación | Ref. PID2021-122442NB-10

Founding-family-controlled firms, intergenerational succession, and firm value

Using a unique, hand-collected data sample and panel-data econometric techniques, we analyse the impact of founding-family control and intergenerational succession on the value of Chilean listed companies. After controlling for firm- and ownership-specific characteristics, we find an inverse U-shaped relationship between a founding family’s degree of ownership and firm value. Hence, family ownership at first increases firm value. However, when family ownership exceeds a threshold of about 38 percent of outstanding shares, the family takes advantage of its power in the firm and extracts wealth from minority shareholders. Further, if the founder of the company is the CEO or chairman of the board, firm value increases. However, family businesses with a subsequent-generation owner-manager destroy value

Preparación y estudio de nanocomposites magnéticos con diferente potencial de empleo

A día de hoy, el estudio de nanocomposites magnéticos se presenta como una línea deinvestigación bastante atractiva, considerando las particulares propiedades de losmateriales obtenidos a escala nanométrica y sus diferentes aplicaciones.Generalmente, las nanopartículas magnéticas de fórmula general MFe2O4 con M = Fe2+,Co2+ y Ni2+ muestran comportamientos magnéticos diferentes en función del catióninvolucrado en la composición y del tamaño de partícula que conforma estas muestras.Un tamaño de partícula dentro del rango nanométrico genera el comportamientosuperparamagnético de algunas muestras, permitiendo la modulación de su respuestaante la presencia o ausencia de un campo magnético externo y, por consiguiente, suposible aplicación en biomedicina, (marcadores en resonancia magnética de imagen, entratamientos de liberación controlada de fármacos, hipertermia magnética, etc.) o enQuímica del medio ambiente.La tesis que se presenta se encuentra estructurada en tres partes y en ella se describe lasíntesis de núcleos de composición MFe2O4 con M = Fe2+, Co2+ o Ni2+ y surecubrimiento con cortezas diferentes (cortezas poliméricas biocompatibles y SiO2-APTES) para la obtención de nanocomposites magnéticos. Los primeros con ampliopotencial de aplicación en biomedicina y los segundos para su empleo como membranasadsorbentes de metales pesados..

Toxic action of copper on the membrane system of a marine diatom measured by flow cytometry

Flow cytometric measurements were used to investigate the toxic action of copper on some Phaeodactylum tricornutum membrane systems. Throughout the time of metal exposure, the percentage of viable cells decreased as copper concentration increased. The forward scatter signal increased as a result of copper exposure. After 72 h of metal exposure, cultures with 0.5 and 1 mg l−1 of copper showed an important increase in the peroxidase activity in comparison with control cells. Cells cultured with copper presented alterations in the membrane potential, increasing as copper concentration increased, after 96 h of metal exposure. Results obtained in this work showed that copper induced a degenerative process in P. tricornutum cells, closely related with alterations or disorders in membrane systems.Xunta de Galicia; XUGA 10301B9

Culture of the marine diatom Phaeodactylum tricornutum with different nitrogen sources: Growth, nutrient conversion and biochemical composition

[Abstract] Cultures of the marine diatom Phaeodaetylum trieornutum were grown in nitrate, nitrite, ammonia or urea media. Nitrogen transformation efficiencies were close to 100% in cultures with nitrate, nitrite or urea, with productivities in dry biomass between 2.2 g.l-1 (urea) and 2.8 g.t1 (nitrate). However growth in ammonia cultures ceased due to a drop in pH of the medium. The biochemical profile was more affected by the growth phase than by the N source. Cellular contents of chlorophylls a and e decreased and the chlorophyll ale ratio increased when cultures entered the stationary phase. Protein and RNA were higher during exponential growth (about 30% and 8% ash free dry weight (AFDW), respectively), but carbohydrates increased up to 220% in the stationary phase. Although significant differences were observed in cellular contents, the biochemical composition (as % AFDW) of the nitrate, nitrite and urea-grown cells was very similar. The highest total fatty acids and polyunsaturated fatty acids (PUFAs) contents in the stationary phase were obtained in the urea-grown cells, with an eicosapentaenoic acid (EPA) content of 26.8 mg.g-1 of dry biomass.[Résumé] Des cultures de la diatomee marine Phaeodaetylum trieornutum ont ete realisees dans des milieux contenant du nitrate, du nitrite, de l'ammonium ou de l'uree. Dans les milieux contenant nitrate, nitrite ou uree, l'efficacite de transformation de l'azote a ete proche de 100 ok, avec des rendements en biomasse seche allant de 2,2 g.l-1 (uree) a 2,8 g.t1 (nitrate), alors que la croissance en presence d'ammonium a ete inhibee a la suite d'une chute de pH du milieu. La phase de croissance a eu une influence plus grande sur Ie profil biochimique que la source d'azote. Les contenus cellulaires en chlorophylle a et e ont diminue et Ie rapport chlorophylle a Ie a augmente pendant la phase stationnaire. La quantite de proteines et d' ARN a ete plus elevee pendant la croissance exponentielle (environ 30 % et 8 % du poids sec ·sans cendres (AFDW) respectivement), tandis que les hydrates de carbone ont augmente de plus de 220 % durant la phase stationnaire. Malgre les differences significatives observees pour les contenus cellulaires, la composition biochimique des cellules (exprimee en % de AFDW) etait comparable dans les milieux contenant nitrate, nitrite ou uree. Le maximum en acides gras totaux et en acides gras polyinsatures (PUFAs) pendant la phase stationnaire a ete observe en presence d'uree, avec un contenu en acide eicosapentaenolque (EPA) de 26.78 mg.g-1 de biomasse seche.Consejo Interinstitucional de Ciencia y Tecnología; n° AGF92073

Rapid assay for the analysis of class III metallothioneins by capillary zone electrophoresis in crude extracts of microalgal cells exposed to cadmium

An optimization strategy for the separation and analysis of class III metallothioneins from a complex matrix by capillary zone electrophoresis (CZE) is presented and illustrated. Metallothioneins are a group of polypeptides used for many organisms to alleviate stresses imposed by exposure to heavy-metal excess. The analysis requires several steps: chromatography on exclusion or anion-exchange columns, ultrafiltration and HPLC with derivatization. In the present paper, a rapid and simple separation technique by CZE with an uncoated polyimide-clad fused-silica capillary is described. This technique permits the analysis of these molecules without prior steps of purification and derivatization. The running conditions were voltage −12 kV, room temperature and 150 mM sodium phosphate buffer (pH 3.5). Based on this preliminary study, CZE with an uncoated fused-silica capillary using sodium phosphate buffer appears to be a useful technique for the separation of class III metallothioneins

Adsorption of atomic oxygen and nitrogen at β-cristobalite (100): a density functionaly theory study

The adsorption of atomic oxygen and nitrogen on the -cristobalite (100) surface is investigated from first principles density functional calculations within the generalized gradient approximation. A periodic SiO2 slab model (6 layers relaxing 4 or 6) ended with a layer of Si or O atoms is employed throughout the study. Several adsorption minima and diffusion transition states have been characterized for the two lowest spin states of both systems. A strong chemisorption is found for either O or N in several sites with both slab endings (e.g., it is found an average adsorption energy of 5.89 eV for O (singlet state) and 4.12 eV for N (doublet state) over the Si face). The approach of O or N on top O gives place to the O2 and NO abstraction reactions without energy barriers. Atomic sticking coefficients and desorption rate constants have been estimated (300 - 1900 K) by using the standard transition state theory. The high adsorption energies found for O and N over silica point out that the atomic recombination processes (i.e., Eley-Rideal and Langmuir-Hinshelwood mechanisms) will play a more important role in the atomic detachment processes than the thermal desorption processes. Furthermore, the different behavior observed for the O and N thermal desorption processes suggests that the published kinetic models for atomic O and N recombination reactions on SiO2 surfaces, based on low adsorption energies (e.g., 3.5 eV for both O and N ), should probably be revised