Efficient explicit finite volume schemes for the shallow water equations with solute transport

This work is concerned with the design and the implementation of efficient and novel numerical techniques in the context of the shallow water equations with solute transport, capable to improve the numerical results achieved by existing explicit approaches. When dealing with realistic applications in Hydraulic Engineering, a compromise between accuracy and computational time is usually required to simulate large temporal and spatial scales in a reasonable time. With the aim to improve the existent numerical methods in such a way to increase accuracy and reduce computational time. Three main contributions are envisaged in this work: a pressure-based source term discretization for the 1D shallow water equations, the analysis and development of a Large Time Step explicit scheme for the 1D and 2D shallow water equations with source terms and the numerical coupling between the 1D and the 2D shallow water equations in a 1D-2D coupled model. The first improvement roughly consists of exploring the pressure and bed slope source terms that appear in the 1D and 2D shallow water equations to discretize them in an intelligent way to avoid extremely reductions in the time step size. On the other hand, the implementation of a Large Time Step scheme is carried out. In order to relax the stability condition associated to explicit schemes and to allow large time step sizes, reducing consequently the numerical diffusion associated to the original explicit scheme. Finally, two 1D-2D coupled models are developed. They are demonstrated to be fully conservative and are able to approximate well the results obtained by a fully 2D model in terms of accuracy, while the computational effort is clearly reduced. All the advances are analysed by means of different test cases, including not only academic configurations but also realistic applications, in which the numerical results achieved by the new numerical techniques proposed in this work are compared with the conventional approaches

Solute Transport Control at Channel Junctions Using Adjoint Sensitivity

Water quality control and the control of contaminant spill in water in particular are becoming a primary need today. Gradient descent sensitivity methods based on the adjoint formulation have proved to be encouraging techniques in this context for river and channel flows. Taking into account that most channels and rivers include junctions with other branches, the objective of this study is to explore the adjoint technique on a channel network to reconstruct the upstream boundary condition of the convection-reaction equation. For this purpose, the one-dimensional shallow water equations and the transport equation for a reactive solute are considered. The control is formulated through the gradient-descent technique supplied with a first-order iterative process. Both the physical and the adjoint equations are supplied with suitable internal boundary conditions at the junction and are numerically solved using a finite volume upwind scheme. The results reveal that the adjoint technique is capable of reconstructing the inlet solute concentration boundary condition in an acceptable number of iterations for both steady state and transient configurations using a downstream measurement location. It was also observed that the reconstruction of the boundary condition tends to be less effective the further away the measurement station is from the target

Experimental Evaluation of Blind Interference Alignment

The proceeding at: 2015 Vehicular Technology Conference (VTC Spring) took place 11-14 May in Glasgow, Ireland.An experimental evaluation of Blind Interference Alignment (BIA) over a hardware platform is presented in this work. In contrast to other transmission techniques such as Linear Zero Forcing Beamforming (LZFB) or Interference Alignment (IA), BIA achieves a growth in Degrees of Freedom (DoF) without channel state information at the transmitter (CSIT). A real implementation based on Orthogonal Frequency Division Multiplexing (OFDM) and LTE parameters is implement on a testbed made up of a transmitter equipped with two antennas and two users equipped with a reconfigurable antenna each. Furthermore, a full CSIT technique such as LZFB is also implemented for comparison purposes. First, the theoretic achievable rates are obtained for both techniques. After that, the bit error rate of both schemes is evaluated regarding the achieved sum-thorughput.This work has been partially funded by research projects COMONSENS (CSD2008-00010), and GRE3N (TEC2011-29006-C03-02)

Algoritmos de regulación en flujos transitorios bidimensionales

El uso de métodos numéricos para predecir la forma de la lámina de agua o las variaciones de caudal en caso de flujos tanto estacionarios como no estacionarios es, hoy en día, una práctica necesaria dentro de la tecnología hidráulica moderna, ya que ofrece la posibilidad de evaluar, de una forma no muy costosa, la respuesta de los sistemas hidráulicos frente a una gran variedad de situaciones prácticas. En particular, la simulación numérica de flujos transitorios permite acceder, entre otras cosas, a la predicción de tiempos de tránsito de las ondas, alcanzados por los valores máximos en distintos puntos del dominio de cálculo. Esta información es esencial para el diseño de estrategias de prevención y puede ser combinada con algoritmos de regulación y optimización. Los problemas que acarrean las grandes precipitaciones y las consiguientes inundaciones es un tema de interés creciente en los últimos años. Grandes pérdidas económicas y sociales son las principales consecuencias que traen consigo estas inundaciones. Para poder actuar de una manera efectiva contra esto, una opción es la utilización de áreas de inundación controlada para almacenar la mayor parte de la crecida y devolver el agua al río una vez haya finalizado. Esto es, por otra parte, un reto, debido a que la aplicación de estos conceptos a cuencas urbanizadas que fueron desarrolladas hace mucho tiempo con zonas bajas ocupadas por infraestructura industrial, comercial y residencial se antoja muy complicada. El trabajo consiste en familiarizarse con modelos de simulación transitoria para flujos bidimensionales existentes en el grupo de investigación, recopilar información de elementos y algoritmos de regulación, establecer un caso test de aplicación y programar la combinación de ambos elementos para ensayar su potencial utilidad

A Simulation Based Optimal Control System For Water Resources

Nowadays, the increasing demand of water resources has become one of the most relevant issues when water supply must be guaranteed as in the case of irrigation comunities. It becomes difficult to provide the predictive optimal behavior of regulation structures when the regime of the flow is changing in time and, moreover, when this regulation modifies the hydraulic conditions of the structure. One of the most widely used solution for control is PID. The disadvantages of PID control are the difficulties in the presence of non-linearities as well as the PID parameters tuning. Taking into account previous works about sluice gate formulation and its hydraulics, an equivalent formulation is going to be applied to obtain the control signal for the gate. This will make possible to build a system that allows the optimal control of the gate in order to obtain, for instance, a desired volume of water in the least time possible with the minimum water loss. In this work, a reformulation of the problem is analyzed and then, an equivalent the control is applied to sluice gate flow to obtain a simulation based control system and a near real-time solution is explored using adjoint variable formulation

Trends in the research of postgraduate students in SFL based on teacher needs and competences

María Pilar López-García. Universidad de Granada - 0000-0002-9884-6332Jerónimo Morales-Cabezas. Universidad de Granada – ORCID 0000-0002-3446-620XRecepción: 29/06/2018 | Aceptado: 17/04/2019Correspondencia a través de ORCID: María Pilar López-García - 0000-0002-9884-6332Los gestores académicos debemos hacer continuas reflexiones sobre las necesidades de los alumnos en formación para diseñar programas didácticos acordes a las nuevas tendencias en la enseñanza de lenguas. Los futuros profesores de español como lengua extranjera (ELE) y/o segunda lengua (L2) que están en proceso de formación se crean –como cualquier individuo que se desenvuelve en un ámbito formativo– diversas expectativas personales cuando acceden al posgrado específico. En esta investigación partimos de un estudio previo sobre necesidades formativas de los futuros docentes de ELE –alumnos de posgrado– y la posterior investigación desarrollada al finalizar un máster. Los principales objetivos de este trabajo consisten, en primer lugar, en analizar un conjunto de necesidades expresadas por este tipo de alumnado y relacionarlas con las competencias docentes descritas en este amplio ámbito. En segundo lugar, estudiaremos una muestra de trabajos fin de máster (TFM) derivados de las investigaciones hechas por los alumnos. Nuestro propósito es ver qué tipo de tendencias o líneas de investigación son predominantes en los diferentes cursos académicos y si se adecuan o no al perfil competencial de ELE, para distinguir qué actividad formativa en este ámbito es más adecuada en función de las necesidades profesionales de estos futuros docentes.Abstract: Academic managers must constantly reflect on the needs of learners in training in order to design teaching programs in line with the new trends in language teaching. Future teachers of Spanish as a Foreign Language (SFL) and/or second language (L2) that are in the process of formation are created –as any individual that is carried out in a formative field– different personal expectations when they accede to the specific postgraduate degree. In this research we start from a previous study on the training needs of the future teachers of SFL –postgraduate students– and the subsequent research developed at the end of the master. The main objectives of this work are, first of all, to analyze a set of needs expressed by this type of student and to relate them to the teaching competences described in this broad field. Secondly, we will look at a sample of master’s dissertation derived from the research done by the students. Our purpose is to see what kind of trends or lines of research are predominant in the different academic courses and whether or not they fit the competency profile of SFL, to distinguish which training activity in this field is best suited to the professional needs of these future teachers

Posibilidades de implantación de una plataforma virtual para la mejora de la comercialización de los cítricos en Andalucía. Necesidades de información de los productores y exportadores

Andalucía es la segunda región productora de cítricos de España, teniendo por tanto una extraordinaria importancia económica y social. Sin embargo, la cadena de valor de los cítricos comprende un sector productor bastante atomizado frente a unos compradores muy concentrados y organizados, y un mercado poco transparente. El objetivo de esta investigación fue determinar las necesidades de información de los principales agentes implicados en la cadena de valor de los cítricos y estudiar las posibilidades que tendría la implantación de una plataforma virtual para mejorar las decisiones empresariales en la comercialización de los productos. Para ello, se emplearon fuentes primarias, centradas en la realización de entrevistas a expertos de la producción de cítricos en Andalucía, segmentando el análisis sobre la base de la naturaleza jurídica y la actividad de los entrevistados. Esta acción estratégica puede ser viable puesto que hay una clara demanda de información por parte de la población encuestada, que representa el 65% de la producción citrícola andaluza. Además, se constató que el modelo de gestión debería ser mixto, públicoprivada. La responsabilidad de la misma debería ser privada, ya que en general se percibió cierta reticencia en la Administración. La mayoría de los encuestados estarían dispuestos a pagar por los servicios que suministre la plataforma, si bien señalaron restricciones en cuanto al acceso, calidad del servicio y precioAndalusia is the second largest citrus producer in Spain, and thus, the citrus industry has an extraordinary economic and social importance in the region. However, the citrus value chain comprises a scattered primary sector in contrast to a very concentrated and well organized purchase and distribution sector, as well as a non-transparent market. The aim of this research was to explore the information needs of the different agents in the citrus value chain and to study the possibilities of implementing a opavirtual platform to share information in order to improve their marketing decisions. Primary sources were used for this work: a survey was conducted among citrus production experts in Andalusia. Survey results were analysed according to the legal nature and the activity of the respondents. The strategic action of implementing an information platform may be feasible since a clear demand for information has been detected from the survey population which represents 65% of the Andalusia citrus production. In addition, a public-private management model was preferred by the respondents to control the platform although the responsibility for it should be private. The majority of respondents would be willing to pay for the services provided by the platform, although some aspects regarding access restrictions service quality and price should be consideredFundación Corporación Tecnológica de Andalucía (CTA) 1480/056

A Comparative Study Of Accuracy And Performance Between A Fully 2D GPU Based And A 1D-2D Coupled Numerical Model In A Real River

Hydraulic simulation is becoming a very widely used tool to provide information about the duration, the extension and the magnitude of a flooding episode. In the last decade, the advances in the numerical schemes, connected to the evolution experimented in the power of computers have allowed to aim for maximum accuracy in the results instead of working with simplified models. In particular, two main implementations have been extensively developed in the recent years: 1D-2D coupled numerical models and fully 2D models under GPU technologies. These strategies allow to simulate a wide range of applications over large domains and time scale problems, computing them at an affordable cost. Both 2D model and 1D-2D coupled model are implemented using a finite volume framework using a conservative upwind cell-centered formulation based on Roe\u27s Riemann solver across the edges. In particular, the 1D-2D model is constructed with a novel technique that computes the average values and solves the Riemann Problem at the coupled edges while the 2D model uses the same numerical method performing the computation by means of the last GPU technology. The topography is represented by means of triangular unstructured meshes for the 2D model and with cross sections for the 1D domain inside the coupled model. Both models were previously validated with experimental measurements, analytical solutions in academic and realistic configurations. A real river configuration with different scenarios and field data is presented. Not only the error made with respect the measurements is analyzed, but also the CPU time is evaluated in order to decide whether or not to use the 1D-2D coupled or the GPU model

Genome-wide identification of genes involved in growth and fermentation activity at low temperature in Saccharomyces cerevisiae

Fermentation at low temperatures is one of the most popular current winemaking practices because of its reported positive impact on the aromatic profile of wines. However, low temperature is an additional hurdle to develop Saccharomyces cerevisiae wine yeasts, which are already stressed by high osmotic pressure, low pH and poor availability of nitrogen sources in grape must. Understanding the mechanisms of adaptation of S. cerevisiae to fermentation at low temperature would help to design strategies for process management, and to select and improve wine yeast strains specifically adapted to this winemaking practice. The problem has been addressed by several approaches in recent years, including transcriptomic and other high-throughput strategies. In this work we used a genome-wide screening of S. cerevisiae diploid mutant strain collections to identify genes that potentially contribute to adaptation to low temperature fermentation conditions. Candidate genes, impaired for growth at low temperatures (12 °C and 18 °C), but not at a permissive temperature (28 °C), were deleted in an industrial homozygous genetic background, wine yeast strain FX10, in both heterozygosis and homozygosis. Some candidate genes were required for growth at low temperatures only in the laboratory yeast genetic background, but not in FX10 (namely the genes involved in aromatic amino acid biosynthesis). Other genes related to ribosome biosynthesis (SNU66 and PAP2) were required for low-temperature fermentation of synthetic must (SM) in the industrial genetic background. This result coincides with our previous findings about translation efficiency with the fitness of different wine yeast strains at low temperature.Funding from the Spanish Government trough MINECO and FEDER funds: MINECO AGL2012-32064 and AGL2015-63629-R grants, INIA RM2012-00007-00-00 grant, MINECO RTC-2014-2186-2 and MINECO PCIN-2015-143 grants is acknowledged.Peer reviewe

Programación de un modelo de cálculo inverso para optimización de fenómenos de transporte

El objetivo de este Trabajo Fin de Grado es el desarrollo de una herramienta de regulación y optimización de flujos con transporte, por medio de modelos basados en variables adjuntas y técnicas de gradiente descendente. También se aplica el modelo a una confluencia de canales.<br /