Partitioning approach for large wind farms: active power control for optimizing power reserve

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Nowadays, large wind farms are expected to guarantee stability of the electrical grid contributing with ancillary services, such as frequency support. To this end, wind farm controllers must set the power generation of each turbine to compensate generation and demand imbalances. With the aim of optimizing primary frequency support, this paper proposes a partitioning approach to split large wind farms into several disjoint subsets of turbines according to the wake propagations through the wind farm. The partitioning problem is solved as a mixed-integer multi-objective optimization problem stated to maximize the strength of the coupling among the turbines due to the wake effect. Thus, no additional information sharing related to the wake propagations needs to be considered between the subsets. Different control tasks are assigned to the local controller of each subset, such that the total power generated meets the power demanded by the grid while the power reserve for enhancing primary frequency support is maximized. Finally, as an application of the proposed model, a decentralized wind farm control strategy is designed and compared with a centralized approach.Peer ReviewedPostprint (author's final draft

Slots Startup Synchronization with Shared Resources Dependency

Producción CientíficaIn this work the authors present a new formulation that allows an optimal schedule of batch processes with length dependence on the synchronization of the startup of the processes. It is also keep into account the distribution of shared resources among the devices.European Union, Horizon 2020 research and innovation programme under grant agreement No 723575 (CoPro)MINECO-FEDER (DPI2015-70975-P

Aproximación a los procesos de desigualdad e integración social. Dispositivos de regulación y "Determinación Política" de las necesidades

En esta intervención queremos presentar la perspectiva que en Colectivo Ioé hemos elaborado a lo largo de varias investigaciones sociológicas sobre la desigualdad e integración social. Primero planteamos una postura metodológica respecto al análisis de las carencias sociales, cuestionando los análisis habituales que se focalizan sólo sobre la descripción de los colectivos carenciales o en la pura aproximación económica, y destacando la importancia de los mecanismos institucionales e ideológicos. Después se presenta un desarrollo concreto de tal metodología mostrando, por un lado, la persistencia y desarrollo de la desigualdad social en España y, a continuación, un análisis de las actuales formas institucionales de "gestión de la pobreza". Se pone el acento en su función homogeneizadora, que pretende reconducir el conflicto social colectivo bien hacia pautas de comportamiento "normalizado" o bien hacia conductas "desviadas" de los individuos. En tercer lugar, se desarrolla un breve análisis del panorama ideológico español contemporáneo, que muestra el predominio de "visiones del mundo" que contemplan la exclusión y marginalidad social como un fenómeno a gestionar profesionalmente, al margen de cualquier reflexión sobre el funcionamiento del sistema social que las genera. Desde esta mentalidad, entendemos, no puede trascenderse la pura "gestión de la pobreza" en la medida en que se asume acríticamente el marco institucional descrito en el apartado anterior. Los elementos propuestos anteriormente articulan nuestra perspectiva de análisis pero, en difinitiva, el reto fundamental es, según nuestra perspectiva, enfrentar el cuarto y último punto: la repolitización de la vida social frente a la mera gestión de la desigualdad

La participación ciudadana. Algunos apuntes a partir del Barómetro Social de España

At the level of proclaimed principles, one of the hallmarks of Western democracy is public participation in political, economic and cultural life. In practice, however, the daily management of these areas is provided by professional politicians, transnational corporations and media oligopolies. This paper seeks to collect in a broad sense the forms of citizen participation in the field of politics. While indirect participation through the electoral process has been remarkable in the last three decades, direct intervention in the public sphere is very limited, except for a more active social minority or, in exceptional cases, of collective mobilization. Both the data from the Social Barometer of Spain as well as quantitative and qualitative surveys of public opinion suggest that we live more in a technocratic or plutocratic society rather than a democratic one. The political model established in Spain in recent decades provides an ambivalent institutional framework for public participation: on the one hand, it affirms the right of participation and sets out some concrete ways that did not exist previously; on the other, the emphasis on delegation (representation mechanisms) imposes restrictions on direct participation in public affairs.En el nivel de los principios proclamados, una de las señas de identidad de las democracias occidentales es la participación de la población en la vida política, económica y cultural. En la práctica, sin embargo, la gestión cotidiana de esas esferas corre a cargo de profesionales de la política, corporaciones transnacionales y oligopolios mediáticos. El presente texto trata de recoger las formas de participación de la ciudadanía en el ámbito de la política en un sentido amplio. Si bien la participación indirecta, a través de procesos electorales, ha sido notable durante las tres últimas décadas, la intervención directa en la esfera pública es muy limitada, salvo para una minoría social más activa o en casos excepcionales de movilización colectiva. Tanto los datos aportados por el Barómetro social de España como los sondeos cuantitativos y cualitativos de opinión pública apuntan a que vivimos en una sociedad tecnocrática o plutocrática, más que democrática. El modelo político establecido en España en las últimas décadas ofrece un marco institucional ambivalente para la participación ciudadana: por un lado, se afirma el derecho a la participación y se establecen algunos cauces concretos que antes no existían; por otro, el énfasis en la delegación (mecanismos de representación) impone unos límites precisos a la participación directa en los asuntos públicos

Dynamics of counterpropagating waves in parametrically forced systems

Parametrically driven waves in weakly dissipative systems with one extended dimension are considered. Multiple scale techniques are used to derive amplitude equations describing the interaction between counterpropagating waves. Dissipation, detuning and forcing are all assumed to be weak and any coupling to mean fields (such as large scale flows in fluid systems) is ignored. If the aspect ratio is moderately large the system is described by a pair of nonlocal equations for the (complex) amplitudes of the waves. The dynamics of these equations are studied both in annular and bounded geometries with lateral walls. The equations admit spatially uniform solutions in the form of standing waves and spatially nonuniform solutions with both simple and complex time-dependence. Transitions among these states are investigated as a function of the driving in three particular cases

A diocese de Miranda do Douro em meados do séc. XVIII segundo as memórias paroquiais de 1758

Tese doutoramento história das populaçõesFeitos os enquadramentos geográfico e humano do território diocesano e das suas instituições. Apresenta-se um estudo mais alargado da vida diocesana. Foram recolhidas informações que nos permitem, entre outros aspectos, saber a rede de implementação das congregações religiosas, quais eram os oragos de cada paróquia; quem apresentava os párocos, o valor dos seus rendimentos e as suas denominações. As vivências religiosas das populações são amplamente tratadas: os santos da sua preferência e o seu enquadramento territorial, os locais onde existiam relíquias, onde se realizavam as festas e romarias de maior expressão e a distribuição das confrarias.Having contextualized both the human and geographic territories of the diocese and its institutions, it’s now shown a broader study of the diocese’s life. The information we collected allows us, among other things, to know and understand how were the religious congregations implemented, which were the patrons of each parish, who presented the parish priests, their income and their denominations. The religious habits of the populations are extensively regarded in this study: their favorite saints and its area’s framework, the localities where relics existed, where the most expressive celebrations and pilgrimages were occurring and the distribution of the brotherhoods

CORRIGENDUM: Surface wave damping in a brimful circular cylinder

As pointed out to us by Mr T. Heath, the following printing errors can be quite misleading when using the formulas in the paper to obtain eigenfrequencies and damping rates to compare with experiments: in (A 13) 1 should read −1 on the right-hand side; in (A 22) and (A 26) Ω20 should read Ω−20; in (A 25) the factor Ω40 must be omitted on the right-hand side. When revising again the printed version of the paper, we discovered several additional misprints: A factor C was omitted in the first two integrals in the expression for J2, immediately following equation (2.9). The sign of the second expression for I1 in (2.23) should be changed. The expression (W0Wz +3WW0z)z=0 should read 2(W0Wz +WW0z)z=0 in equation (2.24). The expression W0(1, z)W0z(1, z) in (2.26) should read W0(r, 0)W0z(r, 0). None of the misprints above affect the results of the paper, which were obtained with the correct expressions

Mean Flow Effects in the Faraday Instability

We study the weakly nonlinear evolution of Faraday waves in a 2D container that is vertically vibrated. In the small viscosity limit, the evolution of the surface waves is coupled to a non-oscillatory mean flow that develops in the bulk of the container. The corresponding long time (Navier-Stokes+amplitude) equations are derived and analyzed numerically. The results indicate that the (usually ignored) mean flow plays an essential role in the stability of the surface waves and in the bifurcated wave patterns

Instant City

En el año 1971 y con motivo del VII Congreso del International Council of Societies of Industrial Design (ICSID), la isla de Ibiza (concretamente la cala Sant Miquel, al norte de la misma) acogió la Instant City, una ciudad efímera que se levantó, ocupó y desmanteló en poco más de un mes. Pasados casi 50 años de este experimento hablamos con Carlos Ferrater sobre sus luces y sombras, poniendo especial énfasis en la sorprendente vigencia que el emblemático proyecto conserva hoy en día.In 1971 on the occasion of the VII Congress of the International Council of Societies of Industrial Design, the island of Ibiza hosted the Instant City, an ephemeral city that was built, occupied and dismantled in little more than a month. After almost 50 years of this experiment we speak with Carlos Ferrater about its lights and shadows, putting special emphasis on the surprising validity that the emblematic project conserves today.Peer Reviewe

Empilhadores - Avaliação de riscos e da fiabilidade humana na sua utilização

O presente trabalho tem por base a aplicação da Análise dos Modos de Falha e seus Efeitos (FMEA) e da Análise de Fiabilidade Humana (HRA), na utilização de empilhadores. A Análise dos Modos de Falha e seus Efeitos (FMEA) incidiu na deteção das falhas potenciais que se reportam ao equipamento, de forma a identificar os perigos, avaliar a probabilidade de ocorrência de um acidente, devido a esse perigo, e detetar as suas possíveis consequências, e com base nos níveis de risco obtidos, foram propostas medidas que permitam maximizar a redução dos riscos na utilização de empilhadores. A Análise de Fiabilidade Humana (HRA) versou na determinação da probabilidade da falha humana acontecer na utilização da máquina, no cumprimento de uma tarefa, em condições ambientais apropriadas e com recursos disponíveis para executá-la, sendo estas falhas classificadas, quantificadas e analisadas, com base em árvores de eventos e em estimativas de probabilidade de erro humano. O Estudo de Caso desenvolveu-se na Empresa CMPS - Sociedade de Revestimentos, S.A., com base na FMEA e na metodologia THERP da HRA, aferidas "in situ", de forma a avaliar e detetar os fatores e deficiências favorecedoras da sinistralidade, sua distribuição setorial e tipo de medidas de prevenção e segurança mais adequadas a implementar para minimizar a ocorrência de novos acidentes. Considerações finais, em que se releva a inclusão destas ferramentas ou de ferramentas similares nas várias indústrias para determinação da fiabilidade geral dos sistemas, em prol da segurança e da eficiência.This work is based on the application of Failure Mode and Effects Analysis (FMEA) and the Human Reliability Analysis (HRA) in the use of forklifts. Analysis of the Failure Modes and Effects Analysis (FMEA) focused on the detection of potential failures that relate to the equipment in order to identify hazards, assess the likelihood of an accident, due to this danger, and detect the possible consequences, and based on risk levels obtained were proposed measures to maximize risk reduction in the use of forklifts. The Human Reliability Analysis (HRA) dealt in determining the likelihood of human error happens when using the machine to perform a task, under appropriate environmental conditions and resources available to execute it. The failures were classified, quantified and analyzed, based on event trees and estimates of the probability of human error. The case study was developed in the Company CMPS - Society for Coatings, SA, and it was based on the FMEA and on the THERP methodology of HRA and, measured "in situ", in order to evaluate and detect weaknesses and the factors favoring the accident, their sectoral distribution and type of prevention and safety measures more effective to be implemented to minimize the occurrence of new accidents. Concluding remarks, which emphasizes the inclusion of these tools or similar tools in various industries to determine the overall reliability of the systems to promote security and efficiency