Downstream-migrating antidunes in sand, gravel and sand-gravel mixtures

River hydrodynamicsBed roughness and flow resistanc

Development and Experimental Validation of a Dynamic Model for a Fresnel Solar Collector

this paper presents a lumped parameter dynamic model of a Fresnel collector field of a solar refrigeration plant. The plant is located in the Escuela Superior de Ingenieros of the University of Seville. The dynamic model parameter model developed can be used as a control model or as a simulation tool to test controllers. The lumped parameters have been determined by using real data from the plant in different operating conditions. The model has been validated against a data validation set obtained from the plant. The model has shown to reproduce the system behavior with a good compromise in accuracy and model complexity

Uso de compost que incluyen cenizas de biomasa para el cultivo de sandía

5 páginas.-- 4 tablas.-- 10 referenciasLa biomasa representa entre el 8 y el 15% del suministro energético mundial como electricidad, calor y combustibles para transporte, y podría contribuir hasta un 33-50% del consumo de energía primaria en 2050. Buena parte de esta energía se obtiene por combustión directa de biomasa generando 476 millones de toneladas de cenizas. Por el contrario de las cenizas derivadas del carbón, las cenizas de biomasa están libres de elementos contaminantes y en el caso de las de biomasa derivada de productos agrícolas y agroindustriales suelen presentar concentraciones apreciables de elementos fertilizantes como K, Mg, además de Ca por lo que su ciclo puede completarse si son reutilizadas en agricultura en lugar de depositadas en vertedero. En el presente trabajo se estudia el uso de un compost mixto de residuos agroindustriales y cenizas de orujo de aceituna como enmienda en un cultivo de sandía (Citrullus lanatus variedad Augusta). Como comparación se usaron tratamientos con el mismo compost de residuos agroindustriales o con fertilización mineral sólo (Control, 220 kg K2O ha-1 como KCl). El compost con cenizas se aplicó a una dosis de 10.000 kg ha-1 y el compost sin cenizas a la dosis de 20.000 kg ha-1. Cada tratamiento se efectuó por cuadruplicado, cultivando la sandía al aire libre. Se determinaron las propiedades del suelo y el rendimiento y estado nutricional del cultivo. Los resultados indican que la inclusión de este tipo de cenizas en las enmiendas de cultivos exigentes nutrientes como potasio puede ser ventajosa, ya que se mantiene la producción del tratamiento control (alrededor de 100000 kg ha-1) pero con mayor tamaño del fruto (más 1,3 kg/fruto en el tratamiento con cenizas).Este trabajo se ha realizado en el marco del proyecto CTQ2013-46804-C2-1-R financiado por el Ministerio de Economía y Competitividad y ha sido parcialmente financiado por el programa FEDER de la Junta de Andalucía. Los autores agradecen a la empresa Fertiormont por la cesión de los productos.Peer reviewe

Generalized harmonic spatial coordinates and hyperbolic shift conditions

We propose a generalization of the condition for harmonic spatial coordinates analogous to the generalization of the harmonic time slices introduced by Bona et al., and closely related to dynamic shift conditions recently proposed by Lindblom and Scheel, and Bona and Palenzuela. These generalized harmonic spatial coordinates imply a condition for the shift vector that has the form of an evolution equation for the shift components. We find that in order to decouple the slicing condition from the evolution equation for the shift it is necessary to use a rescaled shift vector. The initial form of the generalized harmonic shift condition is not spatially covariant, but we propose a simple way to make it fully covariant so that it can be used in coordinate systems other than Cartesian. We also analyze the effect of the shift condition proposed here on the hyperbolicity of the evolution equations of general relativity in 1+1 dimensions and 3+1 spherical symmetry, and study the possible development of blow-ups. Finally, we perform a series of numerical experiments to illustrate the behavior of this shift condition.Comment: 18 pages and 12 figures, extensively revised version explaining in the new Section IV how the shift condition can be made 3-covarian

Comparative Analysis of Muscle Transcriptome between Pig Genotypes Identifies Genes and Regulatory Mechanisms Associated to Growth, Fatness and Metabolism.

Iberian ham production includes both purebred (IB) and Duroc-crossbred (IBxDU) Iberian pigs, which show important differences in meat quality and production traits, such as muscle growth and fatness. This experiment was conducted to investigate gene expression differences, transcriptional regulation and genetic polymorphisms that could be associated with the observed phenotypic differences between IB and IBxDU pigs. Nine IB and 10 IBxDU pigs were slaughtered at birth. Morphometric measures and blood samples were obtained and samples from Biceps femoris muscle were employed for compositional and transcriptome analysis by RNA-Seq technology. Phenotypic differences were evident at this early age, including greater body size and weight in IBxDU and greater Biceps femoris intramuscular fat and plasma cholesterol content in IB newborns. We detected 149 differentially expressed genes between IB and IBxDU neonates (p < 0.01 and Fold-Change > 1. 5). Several were related to adipose and muscle tissues development (DLK1, FGF21 or UBC). The functional interpretation of the transcriptomic differences revealed enrichment of functions and pathways related to lipid metabolism in IB and to cellular and muscle growth in IBxDU pigs. Protein catabolism, cholesterol biosynthesis and immune system were functions enriched in both genotypes. We identified transcription factors potentially affecting the observed gene expression differences. Some of them have known functions on adipogenesis (CEBPA, EGRs), lipid metabolism (PPARGC1B) and myogenesis (FOXOs, MEF2D, MYOD1), which suggest a key role in the meat quality differences existing between IB and IBxDU hams. We also identified several polymorphisms showing differential segregation between IB and IBxDU pigs. Among them, non-synonymous variants were detected in several transcription factors as PPARGC1B and TRIM63 genes, which could be associated to altered gene function. Taken together, these results provide information about candidate genes, metabolic pathways and genetic polymorphisms potentially involved in phenotypic differences between IB and IBxDU pigs associated to meat quality and production traits

Metal-Insulator Transition in the Two-Dimensional Hubbard Model at Half-Filling with Lifetime Effects within the Moment Approach

We explore the effect of the imaginary part of the self-energy, $Im\Sigma(\vec{k},\omega)$, having a single pole, $\Omega(\vec{k},\omega)$, with spectral weight, $\alpha(\vec{k})$, and quasi-particle lifetime, $\Gamma(\vec{k})$, on the density of states. We solve the set of parameters, $\Omega(\vec{k},\omega$), $\alpha(\vec{k})$, and $\Gamma(\vec{k})$ by means of the moment approach (exact sum rules) of Nolting. Our choice for $\Sigma(k,\omega)$, satisfies the Kramers - Kronig relationship automatically. Due to our choice of the self - energy, the system is not a Fermi liquid for any value of the interaction, a result which is also true in the moment approach of Nolting without lifetime effects. By increasing the value of the local interaction, $U/W$, at half-filling ($\rho = 1/2$), we go from a paramagnetic metal to a paramagnetic insulator, (Mott metal - insulator transition ($MMIT$)) for values of $U/W$ of the order of $U/W \geq 1$ ($W$ is the band width) which is in agreement with numerical results for finite lattices and for infinity dimensions ($D = \infty$). These results settle down the main weakness of the spherical approximation of Nolting: a finite gap for any finite value of the interaction, i.e., an insulator for any finite value of $U/W$. Lifetime effects are absolutely indispensable. Our scheme works better than the one of improving the narrowing band factor, $B(\vec{k})$, beyond the spherical approximation of Nolting.Comment: 5 pages and 5 ps figures (included

Constraint and gauge shocks in one-dimensional numerical relativity

We study how different types of blow-ups can occur in systems of hyperbolic evolution equations of the type found in general relativity. In particular, we discuss two independent criteria that can be used to determine when such blow-ups can be expected. One criteria is related with the so-called geometric blow-up leading to gradient catastrophes, while the other is based upon the ODE-mechanism leading to blow-ups within finite time. We show how both mechanisms work in the case of a simple one-dimensional wave equation with a dynamic wave speed and sources, and later explore how those blow-ups can appear in one-dimensional numerical relativity. In the latter case we recover the well known ``gauge shocks'' associated with Bona-Masso type slicing conditions. However, a crucial result of this study has been the identification of a second family of blow-ups associated with the way in which the constraints have been used to construct a hyperbolic formulation. We call these blow-ups ``constraint shocks'' and show that they are formulation specific, and that choices can be made to eliminate them or at least make them less severe.Comment: 19 pages, 8 figures and 1 table, revised version including several amendments suggested by the refere

Characterisation of High Temperature Oxidation Phenomena during AISI 430 Stainless Steel Manufacturing under a Controlled H-2 Atmosphere for Bright Annealing

Localised-in-the-edge oxidation of four AISI 430 alloys was investigated after an industrial bright annealing process. The oxidised surface of each specimen was characterised by X-ray photoelectron spectroscopy (XPS), Raman-spectroscopy and SEM. The results showed that the selective oxidation of Cr and Mn took place at the coil edges of AISI 430. This led to the formation of an oxide scale based on Cr2O3 and MnCr2O4. On the other hand, the formation of Cr(OH)(3) and MnOOH in the outer part of the oxide scale was related to the effect of the H-2-N-2 environment on the annealing furnace. The results concluded that the composition of Cr and Mn in the alloy determined the composition of the oxidation products. However, the effect of annealing time was minor in this oxidation mechanism, which slightly contributed to an increase in the cation diffusion from the steel to the oxide. Finally, the results obtained indicate that the colouration of the coil edges displayed in each studied material varies according to the alloy chemical composition and annealing time.This research was funded by the "Proyectos de I+D Individuales" programme, Centro para el Desarrollo Tecnologico Industrial (CDTI), Ministerio de Economia y Competitividad from the Spanish Government-project "FERRINOP"

Isoterma de langmuir y freundlich como modelos para la adsorción de componentes de ácido nucleico sobre wo3 | langmuir and freundlich isotherms as model for the adsorption of nucleic acid components on wo3

En este trabajo, se estudió el efecto del pH (3-10) en la adsorción de los constituyentes de ácidos nucleicos; nucleobases, nucleósidos y nucleótidos, sobre el trióxido de tungsteno (WO3). Se utilizaron las isotermas de Langmuir y Freundlich para describir los procesos de adsorción. Se observó que el pH neutro favoreció la adsorción de los componentes de ácidos nucleicos. Los datos de adsorción sugieren que existe una considerable diferencia en la capacidad de enlace de las nucleobases y sus derivados sobre el WO3, la cual depende de la arquitectura molecular de las especies adsorbidas. Se encontró que la adsorción de las biomoléculas sobre el catalizador sigue el siguiente orden: Nucleótidos > Nucleósidos > Nucleobases. Los mayores valores de la capacidad máxima de adsorción (Xm) se obtuvieron para los nucleótidos, encontrándose a pH 7 que el CMP’5 (Xm = 64,94 mg/L) > UMP’5 (Xm = 54,64 mg/L) @ GMP’5 (Xm = 54,35 mg/L) > AMP’5 (Xm = 45,05 mg/L). Las constantes de Freundlich (KF) oscilaron entre 4 y 7. Para todos los pH, los nucleósidos y nucleótidos poseen valores de n (constante de intensidad de adsorción) cercanos a la unidad, indicando que los sitios activos del catalizador son equivalentes energéticamente, excepto el AMP’5 a pH 7 (n = 2,16). El pH neutro es óptimo para modificar químicamente la superficie del WO3.Palabras clave: Nucleótido, nucleósido, base nitrogenada, biomoléculas.ABSTRACTIn this paper, we studied the effect of pH (3-10) in the adsorption of nucleic acid constituents; nucleobases, nucleosides and nucleotides, on tungsten trioxide (WO3). Isotherms of Langmuir and Freundlich were used to describe adsorption processes. It was noted that neutral pH favors the adsorption of nucleic acid components. The adsorption date suggests that there is a considerable difference in the binding capacity of the nucleobases and their derivatives on WO3, which depends on the molecular architecture of the adsorbed species. It was found that adsorption of biomolecules onto the catalyst has following sequence: Nucleotide > Nucleoside > Nucleobase. The highest values of the maximum adsorption capacity (Xm) were obtained for nucleotides, finding that at pH 7 the CMP'5 (Xm = 64.94 mg/L) > UMP'5 (Xm = 54.64 mg/L) @ GMP'5 (Xm = 54.35 mg/L) > AMP'5 (Xm = 45.05 mg/L). Freundlich constants (KF) ranged between 4 and 7. For all pH, nucleosides and nucleotides have values of n (constant of adsorption intensity) close to unity, indicating that the active sites of catalyst are energetically equivalent, except the AMP'5 at pH 7 (n = 2.16). The neutral pH is optimum to chemically modify the surface of the WO3.Key words: Nucleotide, nucleoside, nitrogenous base, biomolecules.