Flujo alrededor de un cilindro: efecto de la condición de contorno en la pared y de la anchura del dominio

En el presente trabajo se examina la influencia de la localización de los límites laterales del dominio computacional en el cálculo de los principales parámetros de un flujo bidimensional oscilatorio incompresible alrededor de un cilindro. Los experimentos numéricos se han realizado a un Pr = 0,7 y dentro de un intervalo de números de Reynolds que va desde 60 a 200. Se han utilizado, en todos los casos, mallas ortogonales no uniformes cuyos puntos de cálculo vienen dados por la intersección entre las isolíneas de función de corriente y las de potencial de velocidad de un flujo potencial alrededor de un cilindro. Los resultados obtenidos en este trabajo son comparados con datos experimentales y numéricos.The influence of the location of the lateral computational boundaries on the main parameters of two-dimensional unsteady incompressible flow past a circular cylinder is investigated in the present work. The numerical experiments are realized over 60 < Re < 200 and Pr = 0,7. We use, in al1 cases, non uniform orthogonal grids. Their nodes are tlle intersection between the streamlines and the velocity potencial isolines of a potencial flow around a cylinder. The results obtained in this work are compared with experimental arid numerical data.Peer Reviewe

Analysis of volatile organic compounds in a waste collection centre using multisorbent adsorption and GC/MS thermal desoprtion system

Volatile organic compounds (VOCs) released by waste treatment systems may lead to major impacts such as toxic air levels, discomfort incidents and annoying odours. The main objectives of this work were to identify and quantify selected VOCs, emitted during waste collection and processing, to control exposure hazards. An analytical method, previously developed and validated in our laboratory, for the determination of VOCs within a wide range of volatility and polarity and with variable concentrations was used.Peer ReviewedPostprint (author’s final draft

Biozonacion del Paleogeno continental de la zona oriental de la Cuenca del Ebro mediante carofitas: implicacions en la biozonacion general de carofitas de Europa occidental

A charophyte biozonation of the Paleogene (Thanetian-Chattian) sequences of the Eastern Ebro Basin (NE Spain) is proposed. This biozonation has been based on an intensive sampling carried out on well correlated sections which included, in some cases, fossil mammal localities. Bothfacts haveresultedin agood chronostratigraphic control of the biozonation. One of the most noticeable contributions from this local point of view is the characterization of the Ilerdian in the continental Ebro Basin sequences by the Maedleriella lavocati biozone. Although in afirst approach this biozonation is intended to be local the new data in the Eastern Ebro Basin have enlarged the ranges of some widespread charophyte index species. These changes in the charophyte sp&ies ranges has led to suggest some remarkable modifications of the preexistin~ Riveline' s (1986) charophyte biozonationfor western Europe: 1) TheN. (T. ) thaleri biozone siaried in the Ilerdian and not in the Cuisian. 2) The definition of new Late Eocene (S. labellata) and Late Oligocene (H. lagenalis) biozones. 3) The enlargement of the range of severa1 species which has resulted in suppressionof the Chara notata biozone and in redefinition of Chara microcera, St. pinguis, St. vectensis and Sr. berdotensis biozones. From apaleogeographic point of view the global percentages of pluricontinental, european and iberian species of the Paleogene Eastern Ebro Basin charophyte record suggest some kind of isolation of the charophyte populations in NE Iberia. This isolation could be enhanced by paleogeographic constraints during Bartonian and Latest Priabonian to Stampian transition.Peer Reviewe

ALMA follows streaming of dense gas down to 40 pc from the supermassive black hole in NGC1097

We present a kinematic analysis of the dense molecular gas in the central 200 parsecs of the nearby galaxy NGC1097, based on Cycle 0 observations with the Atacama Large Millimeter/sub-millimeter Array (ALMA). We use the HCN(4-3) line to trace the densest interstellar molecular gas, and quantify its kinematics, and estimate an inflow rate for the molecular gas. We find a striking similarity between the ALMA kinematic data and the analytic spiral inflow model that we have previously constructed based on ionized gas velocity fields on larger scales. We are able to follow dense gas streaming down to 40 pc distance from the supermassive black hole in this Seyfert 1 galaxy. In order to fulfill marginal stability, we deduce that the dense gas is confined to a very thin disc, and we derive a dense gas inflow rate of 0.09 Msun/yr at 40 pc radius. Combined with previous values from the Ha and CO gas, we calculate a combined molecular and ionized gas inflow rate of 0.2 Msun/yr at 40 pc distance from the central supermassive black hole of NGC1097.Comment: Accepted for Publication in the ApJ Letter

Catastrophic senescence and semelparity in the Penna aging model

The catastrophic senescence of the Pacific salmon is among the initial tests used to validate the Penna aging model. Based on the mutation accumulation theory, the sudden decrease in fitness following reproduction may be solely attributed to the semelparity of the species. In this work, we report other consequences of mutation accumulation. Contrary to earlier findings, such dramatic manifestation of aging depends not only on the choice of breeding strategy but also on the value of the reproduction age, R, and the mutation threshold, T. Senescence is catastrophic when $T \leq R$. As the organism's tolerance for harmful genetic mutations increases, the aging process becomes more gradual. We observe senescence that is threshold dependent whenever T>R. That is, the sudden drop in survival rate occurs at age equal to the mutation threshold value

Influence of porosity on the critical currents of trifluoroacetate-MOD YBa2Cu3O7 films

The influence of porosity on the superconducting properties have been investigated on YBa/sub 2/Cu/sub 3/O/sub 7/ thin films deposited on LaAlO/sub 3/ [100] substrates by the so-called Trifluoroacetate (TFA) route. Micro-Raman spectroscopy have been used to determine the concentration of c-axis grains /spl delta/ in different samples and their influence on the final film porosity as observed from SEM imaging. This has been compared with measurements of resistivity and critical currents in the same samples. We prove that this /spl delta/ fraction is the main parameter controlling the porosity and hence the normal-state resistivity of the thin films. The optimization of the microstructure of these YBa/sub 2/Cu/sub 3/O/sub 7/ TFA films allow to have high critical currents : J/sub c/ = 3 /spl times/ 10/sup 6/ A/cm/sup 2/ at 77 K

Propiedades mecánicas a escala nanométrica de YSZ y GDC usados como electrolitos en pilas de combustible de óxido sólido

El objetivo del presente trabajo es evaluar y comparar las propiedades mecánicas de los electrolitos basados en la circona estabilizada con itria (“yttria stabilized zirconia”, YSZ) y ceria dopada con gadolinia (“gadolinia doped ceria”, GDC), para pilas de combustible de óxido sólido (SOFCs). Ambos materiales, de 200 μm de espesor, se conformaron mediante prensado uniaxial y sinterizaron a 1350ºC. La dureza (H), módulo de Young (E) y tenacidad a fractura (KIC) de los mismos se determinaron mediante la técnica de nanoindentación instrumentada, usando una punta Berkovich de diamante, para diferentes cargas aplicadas: 5, 10, 30, 100, 500 y 650 mN. Las huellas residuales de las indentaciones han sido observadas mediante microscopia electrónica de alta resolución (FE-SEM). Los resultados de H, E y KIC del GDC fueron aproximadamente un 20% inferiores respecto a los del YSZ.Postprint (published version

Essential protein P116 extracts cholesterol and other indispensable lipids for Mycoplasmas

Mycoplasma pneumoniae, responsible for approximately 30% of community-acquired human pneumonia, needs to extract lipids from the host environment for survival and proliferation. Here, we report a comprehensive structural and functional analysis of the previously uncharacterized protein P116 (MPN_213). Single-particle cryo-electron microscopy of P116 reveals a homodimer presenting a previously unseen fold, forming a huge hydrophobic cavity, which is fully accessible to solvent. Lipidomics analysis shows that P116 specifically extracts lipids such as phosphatidylcholine, sphingomyelin and cholesterol. Structures of different conformational states reveal the mechanism by which lipids are extracted. This finding immediately suggests a way to control Mycoplasma infection by interfering with lipid uptake.We thank L. Company and I. Fernández-Vidal for their support during MALS and mass spectroscopy measurements, A. Iborra (Servei de Cultius Cellulars, Anticossos Citometria, UAB) for his assistance with immunizing mice, D. Santos for his assistance in the radioactivity experiment and R. Pérez-Luque and D. Aparicio for their constant support and discussions. J. P. was funded by grants BIO2017-84166-R and PID2021-125632OB-C22 from the ministerio de Ciencia, Innovación y Universidades (MICINN, Spain). I. F. was funded by MICINN-Spain grant PID2021-125632OB-C21. A. S. F. was supported by the Deutsche Forschungsgemeinschaft (FR 1653/14-1 for MS and, FR 1653/6-3 for LS) and the Research Training Group iMOL (GRK 2566/1 for SM)