1,742 research outputs found

    Assessment of unintentional islanding operations in distribution networks with large induction motors

    Get PDF
    This paper is aimed at assessing the impact of unintentional islanding operations (IOs) in the presence of large induction motors (IMs) within distribution networks (DNs). When a fault occurs,followingthecircuitbreaker(CB)faultclearing,theIMsacttransientlyasgenerators,duetoits inertia, until the CB reclosing takes place. The present work is the outcome of a project carried out in a small DN, where ¿eld measurements were recorded over two years. This paper provides a detailed description of the test system, a selected list of ¿eld measurements, and a discussion on modeling guidelinesusedtocreatethemodeloftheactualpowersystem. Themaingoalistovalidatethesystem model by comparing ¿eld measurements with simulation results. The comparison of simulations and ¿eld measurements prove the appropriateness of the modeling guidelines used in this work and highlight the high accuracy achieved in the implemented three-phase Matlab/Simulink modelPostprint (published version

    A new Phoenician location discovered in the Bay of Cádiz: El Cerro del Castillo, Chiclana

    Get PDF
    Los recientes hallazgos arqueológicos en el casco antiguo de Chiclana han aportado nuevos datos sobre la colonización fenicia en la bahía de Cádiz. El importante descubrimiento de un recinto fortificado, correspondiente al primer momento de la misma y de la creación de factorías en contexto peninsular, supone un avance significativo para el conocimiento de la organización territorial del momento y una nueva fuente de datos para la investigación arqueológica e histórica actual. El hecho de que ahora sean tres los enclaves fenicios existentes en la bahía: Cádiz, Chiclana y Doña Blanca (El Puerto de Santa María), permite una mejor interpretación de los textos griegos, que denominaban a esta zona “Gadeira” y al templo de “Melkart”, en Chiclana “puerta de Occidente”.The recent archeological findings in old uptown Chiclana have contributed new data about the Phoenician settlements in the Cádiz Bay. The important discovery of a fortified enclosure, in snchrony with the first Phoenician colonization and also with the creation of factories within the peninsular context, constitutes a significant advance in the present archaeological and historiacal research. The fact that we now have there Phoenician settlements in the Bay area, Cádiz, Chiclana and Doña Blanca, allows us a more accurate interpretation of the Greek text wich refered to this location as Gadeira and to the Melkart temple as the “gate to the West”

    VIE Project: Cultural values and socioeconomic factors as determinants of entrepreneurial intentions

    Get PDF
    This paper describes a research project currently being developed by the authors. It aims to analyse the role played by psychosocial, cultural and socioeconomic factors in shaping the entrepreneurial intention. Survey methods will be used on a population of potential entrepreneurs (having not yet performed actual entrepreneurial behaviours). In this sense, undergraduate students and individuals contacting business support centres will be considered as part of the sample. We expect to get a clearer understanding of the psychosocial elements, socioeconomic factors and cultural values affecting the venture-creation decision. The results would be important to policy makers (showing them what to encourage), to practitioners (what to do better), and to researchers (what to clarify)

    Cell surface immobilization of GABAARs in cerebellar granule cells depends on the M3/M4 cytoplasmatic loop of the alpha 1 subunit

    Get PDF
    Gamma-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the vertebrate brain. The localization of GABA receptors type A (GABAARs) at strategically located domains of the neuronal membrane is of vital importance for fast inhibitory synapse transmission efficacy. We have shown before that the lateral mobility of GABAARs depends on subunit composition of the complex. To study the lateral mobility of GABAARs in living, cultured neurons, we transfected cerebellar granule cells with either the complete 1 GABAAR subunit or with a truncation of the 1 subunit that lacks the major intracellular loop (M3/M4). We examined the location and lateral mobility of receptors containing both versions of the 1 subunit in living neurons. From fluorescence recovery after photobleaching experiments we present novel evidences that the intracellular M3/M4 loop of the 1 subunit restricts the lateral mobility of GABAARs when expressed in neurons. In addition, our immunocytochemical studies suggested that receptors containing the truncated subunit seem to be unable to reach synaptic localizations. Here we show for the first time that the 1 intracellular loop (M3/M4) domain has a relevant role in controlling the lateral mobility of GABAARs in neurons, and we believe that this is a novel and important contribution in neurobiology of GABAA receptors

    Accounting for changes in the Spanish wage distribution : the role of employment composition

    Get PDF
    A pesar de una rápida disminución del desempleo, los salarios reales en España apenas aumentaron durante el periodo 1995-2006. Una posible explicación de este comportamiento se refiere a la importancia de los efectos composición derivados de algunos cambios estructurales, tales como el aumento del peso del empleo en la construcción y en el sector servicios, el incremento de la participación laboral femenina, y la llegada masiva de inmigrantes. Utilizando datos de tres olas de la Encuesta de Estructura Salarial, se descompone la variación salarial observada durante este periodo en dos componentes, el debido a los cambios en las características de los puestos de trabajo y de los trabajadores, y el causado por los cambios en los rendimientos de dichas características. Así, mediante regresiones cuantílicas que estiman ecuaciones de salarios condicionadas a determinados percentiles de la distribución salarial, se construyen las istribuciones contrafactuales que se hubieran observado de haberse mantenido constantes las características de los puestos de trabajo y de los trabajadores. El principal resultado es que la falta de crecimiento de los salarios reales en España durante el periodo 1995-2006 se debe, sobre todo, a la caída de los rendimientos, especialmente de la educación y de la experiencia laboral en los deciles elevados de la distribución salarial, y no tanto a cambios en la composición del empleo que, computados sobre un conjunto amplio de características, tuvieron un efecto global positivo sobre los salario

    Analysis of the Zone Connecting Consecutive Sectors in Generalized Distillation Columns by Using the Ponchon-Savarit Method

    Get PDF
    Ponchon-Savarit is a classical graphical method for the design of binary distillation columns. This method is still widely used, mainly with didactical purposes, though it is also valid for preliminary calculations. Nevertheless, no complete description has been found in books and situations such as different thermal feed conditions, multiple feeds, possibilities to extract by-products or to add or remove heat, are not always considered. In this work we provide, a systematic analysis of the Ponchon-Savarit method by developing generalized equations for the operating lines or difference points, as well as a consistent analysis of what may happen in the zone between two consecutive trays of the corresponding sectors separated by a lateral stream of feed, product, or a heat removal or addition. The graphical interpretation of all situations shown allows a clarifying view of the different possibilities in the rectifying column and completes the existing literature about this method

    Monitoring Muscle Stem Cell Cultures with Impedance Spectroscopy

    Get PDF
    The aim of this work is to present a new circuit for the real-time monitoring the processes of cellular growth and differentiation of skeletal myoblast cell cultures. An impedance spectroscopy Oscillation-Based technique is proposed for the test circuit, converting the biological system into a voltage oscillator, and avoiding the use of very high performance circuitry or equipment. This technique proved to be successful in the monitoring of cell cultures growth levels and could be useful for determining the degree of differentiation achieved, of practical implications in tissue engineering.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-

    Modeling the external flow of a novel HorseShoe receiver and the evaluation of thermal performance

    Get PDF
    The linear receiver of a Parabolic Trough Collector is the most critical element in the entire system. The Universal Vacuum Air Collector concept is the most extended type of receiver in both experimental and industrial facilities. Besides their considerable cost, their efficiency usually drops as operation time passes. This is mainly due to a partial loss of vacuum in the evacuated annulus between the absorber and the glass cover. An alternative design called HorseShoe receiver is proposed in this work, whose main goal is to maintain the thermal performance throughout its entire lifespan. This innovative receiver is indicated for low-to-medium temperature ranges, which is particularly suitable for solar heat for industrial processes. It consists of a horseshoe-like cavity absorber having its upper border insulated. In addition, two main advantages can be taken by using two symmetric lenses as glass cover: reconcentrate solar radiation into the cavity (improvement of the intercept factor) and protect stratification conditions (reduction of thermal losses). A transient numerical model with customized boundary conditions has been implemented to evaluate both thermal performance and temperature difference in the absorber domain, which is critical for the thermal stress conditions. For that purpose and as a key contribution, not only the Heat Transfer Fluid (HTF) temperature but also the heat transfer coefficient in the duct are set. In particular, HTF temperature ranges from 80 °C to 220 °C and the inner heat transfer coefficient from 600 W/(mK) to 1800 W/(mK). Results show that numerical thermal performance is above 96%, which is mainly due to the reduction of thermal radiation losses, where the absorber active surface emittance is . (...)Second (corresponding) author J.J. Serrano-Aguilera acknowledges the support provided by Junta de Andalucía (Government of Andalusia) and Universidad de Málaga for the source of funding for the HERTERSOL project (UMA18-FEDERJA-195), as well as to Ministerio de Ciencia, Innovación Universidades (Spain) by means of the postdoc position: Ref No. FJCI-2017-32403 (Juan de la Cierva-Formación Postdoc Grant). Third author acknowledges the support of Universidad de Málaga, Spain through the Project WALICON, 2021. Authors also acknowledge funding for open access charge: Universidad de Málaga / CBUA

    Horizontal collaboration in freight transport: concepts, benefits and environmental challenges

    Get PDF
    [EN] Since its appearance in the 1990s, horizontal collaboration (HC) practices have revealed themselves as catalyzers for optimizing the distribution of goods in freight transport logistics. After introducing the main concepts related to HC, this paper offers a literature review on the topic and provides a classification of best practices in HC. Then, the paper analyses the main benefits and optimization challenges associated with the use of HC at the strategic, tactical, and operational levels. Emerging trends such as the concept of ` green' or environmentally- friendly HC in freight transport logistics are also introduced. Finally, the paper discusses the need of using hybrid optimization methods, such as simheuristics and learnheuristics, in solving some of the previously identified challenges in real- life scenarios dominated by uncertainty and dynamic conditions.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness & FEDER (TRA2013-48180-C3-P, TRA2015-71883-REDT), The Erasmus+ program (2016-1-ES01-KA108-023465), the Ibero American Program of Science and Technology for Development (CYTED2014-515RT-0489), the CAN Foundation (CAN2014-3758, CAN2015-70473), and the Spanish Ministry of Education (FPU-14/00024).Serrano-Hernandez, A.; Juan, AA.; Faulin, J.; Perez-Bernabeu, E. (2017). Horizontal collaboration in freight transport: concepts, benefits and environmental challenges. SORT. Statistics and Operations Research Transactions. 41(2):393-414. https://doi.org/10.2436/20.8080.02.65S39341441
    corecore