Study of the efflux velocity induced by two propellers

Present analysis is related with seabed erosion caused during docking and undocking maneuvering. Twin propellers without rudder were studied using a physical model with a fixed clearance distance and three different rotating velocities. Experimental results were compared to theoretical expressions of the efflux velocity, axial velocity and finally maximum bed velocity. Efflux velocity equations overestimate the experimental results, whereas axial velocity computed using the Dutch method fits reasonably well the experimental data. However, when maximum bed velocity expressions are compared to experimental results, German method behaves better with an over estimation if a quadratic superposition of the single jets is used.Postprint (published version

El mercado laboral argentino en la posconvertibilidad (2003 - 2015): entre la crisis neoliberal y los límites estructurales de la economía

The article proposes to study the evolution of the Argentine labor market in the post-convertibility period, as well as its main transformations. To do this, different variables are analyzed (employment, salary, employment relationship quality, and urban informal sector evolution), based on considering land rent and the productivity lag of the Argentine economy as the structural determinants of the accumulation process of Argentine capital. The results show a significant reversal of the trends that operated since the mid -1970s, particularly toward the 1990s, so that the latter period ended with substantially better levels. However, this recovery was stagnated in 2011-2012. From a long-term perspective, this shows a working population affected by a differentiation in their reproductive conditions, much deeper than those in the past.O artigo propõe estudar a evolução do mercado de trabalho argentino na pós-conversibilidade, bem como suas principais transformações. Para isso, analisam-se diferentes variáveis (emprego, salário, qualidade do vínculo empregatício, evolução do setor informal urbano), considerando a renda da terra e a defasagem de produtividade da economia argentina como determinantes estruturais do processo de acumulação de capital argentino. Os resultados mostram uma reversão significativa das tendências que operaram desde meados da década de 1970, particularmente até a década de 1990, de modo que o período fechou com níveis substancialmente melhores. No entanto, esta recuperação estagnou no período 2011-2012, que, a partir de uma perspetiva de longo prazo, mostra uma população trabalhadora atravessada por uma diferenciação nas suas condições de reprodução, muito mais profunda do que as que existiam no passado.El artículo se propone estudiar la evolución del mercado laboral argentino en la posconvertibilidad, así como sus principales transformaciones. Para ello, se analizan diferentes variables (empleo, salario, calidad del vínculo laboral, evolución del sector informal urbano) a partir de considerar a la renta de la tierra y el rezago de productividad de la economía argentina como los determinantes estructurales del proceso de acumulación de capital argentino. Entre los resultados se observa una importante reversión de las tendencias que operaron desde mediados de la década de 1970, particularmente hacia la de 1990, de modo que el periodo se cerró con niveles sustancialmente mejores. No obstante, dicha recuperación se estancó hacia 2011 - 2012, lo cual, desde una perspectiva de largo plazo, muestra una población trabajadora atravesada por una diferenciación en sus condiciones de reproducción, mucho más profundas que las existentes en el pasado

Seasonal circulation over the Catalan inner-shelf (northwest Mediterranean Sea)

This study characterizes the seasonal cycle of the Catalan inner-shelf circulation using observations and complementary numerical results. The relation between seasonal circulation and forcing mechanisms is explored through the depth-averaged momentum balance, for the period between May 2010 and April 2011, when velocity observations were partially available. The monthly-mean along-shelf flow is mainly controlled by the along-shelf pressure gradient and by surface and bottom stresses. During summer, fall, and winter, the along-shelf momentum balance is dominated by the barotropic pressure gradient and local winds. During spring, both wind stress and pressure gradient act in the same direction and are compensated by bottom stress. In the cross-shelf direction the dominant forces are in geostrophic balance, consistent with dynamic altimetry data. Key Points A hydrodynamic model is implemented for the first time in Catalan inner-shelf. Frictional and pressure gradient are revealed as the main forcing mechanisms A clear seasonal pattern is found in the current velocity.Peer ReviewedPostprint (published version

Un modelo numérico en elementos finitos para la corriente inducida por la marea. Aplicaciones al Estrecho de Gibraltar

Mediante un modelo numérico quasi-3D en elementos finitos que resuelve las ecuaciones de aguas someras a través de una técnica de descomposición armónica, se ha estudiado el comportamiento de la marea en el Estrecho de Gibraltar. En esta región se acoplan dos regímenes de marea sustancialmente diferentes, el correspondiente al océano Atlántico y el de la cuenca mediterránea. Los resultados del modelo confirman la preponderancia de la circulación inducida por la marea en el flujo local de la zona. También se ha comprobado la importancia que en este ámbito tienen los efectos de la difusión turbulenta, de la fricción con el fondo, de la geometría del dominio y de la interacción de las componentes mareales con la circulación residual. El empleo de una interpolación de orden superior para la altura de la superficie libre y de una formulación no lineal para la fricción con el fondo debe permitir mejorar el grado de ajuste entre los resultados numéricos obtenidos y los datos disponibles.Tidal wave propagation patterns in the Gibraltar Strait are analyzed by means of a quasi- 3D finite element model of the shallow water equations whose solver is based on a harmonic descomposition technique. In this region, two substantially different tidal regimes are coupled, the one corresponding to the Atlantic Ocean and that of the Mediterranean basin. The model results confirm that the tidal contribution is prevailing within local circulation patterns. Moreover, our solutions suggest that the turbulent diffusion of momentum, bottom friction effects, the geometry of the Strait and the tide-current interactions have an important influence on the tidal propagations patterns. The use both of a higher order interpolation scheme for the sea surface height and a non-linear formulation for bottom friction is envisaged as a means to obtain better agreement between model results and experimental data.Peer Reviewe

AAL platform with a “de facto” standard communication interface (TICO): Training in home control in special education

Framed within a long-term cooperation between university and special education teachers, training in alternative communication skills and home control was realized using the “TICO” interface, a communication panel editor extensively used in special education schools. From a technological view we follow AAL technology trends by integrating a successful interface in a heterogeneous services AAL platform, focusing on a functional view. Educationally, a very flexible interface in line with communication training allows dynamic adjustment of complexity, enhanced by an accessible mindset and virtual elements significance already in use, offers specific interaction feedback, adapts to the evolving needs and capacities and improves the personal autonomy and self-confidence of children at school and home. TICO-home-control was installed during the last school year in the library of a special education school to study adaptations and training strategies to enhance the autonomy opportunities of its pupils. The methodology involved a case study and structured and semi-structured observations. Five children, considered unable to use commercial home control systems were trained obtaining good results in enabling them to use an open home control system. Moreover this AAL platform has proved efficient in training children in previous cognitive steps like virtual representation and cause-effect interaction

Evolución en planta/perfil de una playa. Métodos predictivos

[ES] La regeneración/alimentación artificial de una playa supone reproducir una costa sedimentaria que, al igual que las costas naturales, estará sometida a una serie de procesos evolutivos. Estos procesos se esquematizan mediante el estudio de los cambios en planta y perfil de la playa, los cuales son comunes tanto para costas naturales como artificiales. A lo largo de este trabajo se presentan una serie de herramientas para evaluar tales cambios y, por tanto, para estimar la durabilidad de las obras de regeneración o, al menos, las fases evolutivas por las que pasarán.Parte de este trabajo ha sido realizado gracias a la colaboración del Programa de Clima Marítimo (Ente Público de Puertos del Estado) a través del convenio Procesos Hidrodinámicos en Zona de Rompientes.Sánchez-Arcilla Conejo, A.; Jiménez, JA. (1995). Evolución en planta/perfil de una playa. Métodos predictivos. Ingeniería del Agua. 2(1 Extraordinario):119-132. https://doi.org/10.4995/ia.1995.2662SWORD11913221 ExtraordinarioBerenguer, J.M. y Enríquez, J. (1988). Design of pocket beaches. Proc. 21st Coastal Eng. Conf.,ASCE, 1411-1425.Bodge, K. (1992). Representing equilibrium beach profiles with an exponential expression. J. of Coastal Research. 8, 47-55.Bruun, P. (1953). Forms of equilibrium coasts with littoral drift.Tech. Rep. 3, University of California, Engineering Research Laboratory, Berkeley.Bruun, P. (1954). Coast erosion and the development of beach profiles. Beach Erosion Board, Techn. Memo. 44.CUR. (1988). Manual on Artificial Beach Nourishment.Rijkswaterstaat, The Netherlands, 195 pp y anejos.Dalrymple, R.A. (1992). Prediction of storm/normal beach profiles. J. of Waterway. Port. Coastal and Ocean Engineering. 118, 2, 193-200.Dalrymple, R.A. y Thompson, W. (1976). Study of equilibrium beach profiles. Proc. 15th Coastal Eng. Conf.. ASCE. 1277-1296.Dean, R.G. (1973). Heuristic models of sand transpon in the surf zone. Proc. of the Conf. on Engineering Dynamics in the surf zone. 208-214.Dean, R.G. (1977). Equilibrium beach profiles: US Atlantic and Gulf Coasts. Dept. of Civil Eng., Ocean Eng. Tech. Rep. 12, Univ. of Delaware.Dean, R.G. (1997). Equilibrium beach profiles: characteristics and applications. J. of Coastal Research. 7, 1, 53-84.Dean, R.G. y Maurmeyer, E.M. (1983). Models for beach profile response. En: Komar, P.D. (ed.), Handbook of Coastal Processes and Erosion.CRC Press, Boca Ratón, 151-166.Dean, R.G. y Yoo, C. 1993. Predictability of beach nouríshment perfomance. En: Stauble, D.K. y Kraus, N.C. (eds.), Beach Nourishment Engineering and Management Considerations.ASCE, 86-102.De Vriend, H.J.; Zyserman, J.; Nicholson, J.; Roelvink, J.A.; Pechón, P. y Southgate, H.N. (1994). Medium-term 2DH coastal área modelling. Coastal Engineering. 21. 193-224.Garau, C. (1979). Condicionantes de la estabilidad de playas. A nálisis de la función polar de los salientes. II Curso de Ingeniería Oceanogràfica y Portuaria. Santander.Hedegaard, I.B.; Roelvink, J.A.; Southgate, H.; Pechón, P.; Nicholson, J. y Hamm, L. (1992). Intercomparison of coastal profile models. Proc. 23rd Coastal Eng. Conf.. ASCE, 2108-2121.Horikawa, K. (1988) Nearshore Dynamics and Coastal Processes. University of Tokyo Press, Tokyo.Hoyle, J.W. y King, G.T. (7955). The orígin and stability of beaches. Proc. 6th Coastal Eng. Conf.. ASCE,'281-301.Hsu, J.R.C. y Evans, C. (1989). Parabolic hay shapes and applications. Proc. Institution of Civil Engineers. 87, 557-570.Inman, D.L.; Elwany, M.H.S. y Jenkins, S.A. (1993). Shoreríse and bar-berm profiles on ocean beaches. J. of Geophysical Research, 98. C10.18181 -18199.Jiménez, J.A. (1995). BEACH1L. Laboratori d'Enginyeria Marítima, Universitat Politécnica de Catalunya, Barcelona, 41 pp y anejos.Jiménez, J.A. y Sánchez-Arcilla, A. (1992). Simulación de cambios a corto plazo en la línea de costa. Revista de Obras Públicas. 3315, 41-51.Jiménez, J.A. y Sánchez-Arcilla, A. (1993). Influencia de la pendiente en la evolución del perfil de playa. II Jornadas Españolas de Ingeniería de Costas y Puertos. Gijón (en prensa).Jiménez, J.A.; Sánchez-Arcilla, A. y Stive, M.J.F. (1993). Discussion on Prediction of storm/normal beach profiles. J. of Waterway, Port, Coastal and Ocean Engineering, 119, 4, 466-468.Jiménez, J.A.; Valdemoro, H. y Sánchez-Arcilla, A. (1995). Discussion on A nalysis of bayed beaches in static equilibríum. J. of Waterway. Port. Coastal and Ocean Engineering.Mav/June (en prensa).Komar, P.D. (1976). Beach Processes and Sedimentation. Prentice-Hall. Englewood Cliffs, 429 pp.Komar, P.D. y McDougal, W.G. (1994). The analysis of exponential beach profiles. J. of Coastal Research. 10, 1, 59-69.Kraus, N.C. (1985). Prediction models of shoreline change. En: Horikawa, K. (ed.), Nearshore Dynamics and Coastal Processes. University of Tokyo Press, Tokyo, 321-366.Kriebel, D.L. y Dean, R.G. (7995). Convolution method for time-dependent beach-profile response. J. of Waterway. Port. Coastal and Ocean Engineering. 119, 2, 204-226.Kriebel, D.L.; Kraus, N.C. y Larson, M. (1991). Engineering methods for predicting beach profile response. Coastal Sediments' 91.ASCE, 557-571.Larson, M. (1955). Ouantification of beach profile change.Report 1008, Dept. of water Resources Eng., Lund University.Larson, M. (1991). Equilibríum beach profiles of a beach with varying grain size. Coastal Sediments'91. ASCE, 905-919.Larson, M.; Hanson, H. y Kraus, N.C. (1987). Analytical solutions of the one-line model of shoreline change. Tech. Rep. CERC-87-15.Le Blond, P.H. (1972). On the formation of spiral beaches. Proc. 13th Coastal Eng. Conf.. ASCE, 1331-1345.Negro, V. (1990). La variabilidad de los perfiles de playa. Perfiles de verano e invierno. Análisis histórico(1a parte). Revista de Obras Publicas. Marzo 1990, 23-29.Ozasa, H. y Brampton, A.H. (1980). Mathematical modelling of beaches backed by seawalls. Coastal Engineering. 4, 1, 47-64.Pelnard-Considere, R. (1956). Essai de theorie de l'evolution des formes de rivage de sable et de galets. 4th Journees de l'Hydraulique. Question III, Rapport 1, 289-298.Rivero, F. (1995). PROPS. Laboratori d'Enginyeria Marítima, Universitat Politécnica de Catalunya, Barcelona.Sánchez-Arcilla, A. y Jiménez, J.A. (1994). Ingeniería de playas (I): conceptos de morofología costera. Ingeniería del Agua. 1, 2, 97-114.Short, A.D. (ed.) (]993). Beach and surf zone morphodynamics. J. of Coastal Research.Special Issue 15.Silvester, R. (1970). Growth of crenulated shaped bays to equilibríum. J. of Waterways and Harbours División. 96, WW2, 275-287.Silvester, R. y Hsu, J.R.C. (1991). New and oíd ideas in coastal sedimentation. Reviews in Aquatic Sciences. 4, 4, 375-410.0Steetzel, H.J. (1993). Cross-shore transpon during storm surges.Ph.D. Thesis, Delft University of Technology, 242pp.Sunamura, T. (1984). Quantitativeprediction ofbeach-face slopes. Geological Soc. of Amer. Bull..95, 242-245.Sunamura, T. (1985). Beach morphologies and their change. En: Horikawa, K. (ed.), Nearshore Dynamics and Coastal Processes. Univ. of Tokyo Press, Tokyo, 136-157.Tan, S.K. y Chiew, Y.M. (1994). Analysis of bayed beaches in static equilibríum. J. of Waterway. Port. Coastal and Ocean Engineering. 120. 2, 145-153.Vellinga, P. (1982). Beach and dune erosión duríng storm. surges. Coastal Engineering, 6, 806-819.Vellinga, P. (1986). Beach and dune erosión during storm surges. Ph. D. Thesis, Delft University of Technology.Walton, T.L. (1994). Shoreline evolution for tapered beach fill. J. of Waterway. Port. Coastal and Ocean Engineering. 120, 6, 651-655. Wiegel, R.L. (1964) Oceanographic Engineering. Prentice-Hall, Englewood Cliffs.Wind, H.G. (1994). An analytical model of crenulate shaped beaches. Coastal Engineering. 23. 243-253.Yasso, W.E. (1965). Plan geometry of headland hay beaches. J. of Geology. 73. 702-714

Superhydrophobic supported Ag-NPs@ZnO-nanorods with photoactivity in the visible range

In this article we present a new type of 1D nanostructures consisting of supported hollow ZnO nanorods (NRs) decorated with Ag nanoparticles (NPs). The 3D reconstruction by high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) electron tomography reveals that the Ag NPs are distributed along the hollow interior of the ZnO NRs. Supported and vertically aligned Ag-NPs@ZnO-NRs grow at low temperature (135 °C) by plasma enhanced chemical vapour deposition on heterostructured substrates fabricated by sputtered deposition of silver on flat surfaces of Si wafers, quartz slides or ITO. The growth mechanisms of these structures and their wetting behavior before and after visible light irradiation are critically discussed. The as prepared surfaces are superhydrophobic with water contact angles higher than 150°. These surfaces turn into superhydrophilic with water contact angles lower than 10° after prolonged irradiation under both visible and UV light. The evolution rate of the wetting angle and its dependence on the light characteristics are related to the nanostructure and the presence of silver embedded within the ZnO NRs. ÂEuropean Union NMP3-CT-2006- 032583Ministerio de Ciencia e Innovación MAT2010-21228, MAT2010-18447, CSD2008-00023Junta de Andalucía P09-TEP-5283, CTS-518

Evaluation of load-following reserves for power systems with significant RES penetration considering risk management

In this study a novel two-stage stochastic programming based day-ahead joint energy and reserve scheduling model is developed. Demand-side as a reserve resource is explicitly modeled through responsive load aggregations, as well as large industrial consumers that directly participate in the scheduling procedure. Furthermore, a risk-hedging measure is introduced, namely the Conditional Value-at-Risk (CVaR), to analyze the behavior of energy and reserve scheduling by both the generation and the demand-side for a risk-averse ISO. The proposed methodology is tested on the practical non-interconnected insular power system of Crete, Greece, which is characterized by a significant penetration of Renewable Energy Sources (RES).Es la versión aceptada del documento. Se puede consultar la versión final en el DOI 10.1109/SEGE.2015.732457

Optimal generic energy storage system offering in day-ahead electricity markets

This paper models the offers and bids of a generic storage system in an electricity market through stochastic mixed integer linear programming. The objective function aims at maximizing the profit from buying or selling energy for a general storage system. Some parameters such as storage system efficiency, losses of the energy stored and marginal costs are parameterized to evaluate the offers and bids. Market prices are forecasted for 24 hours using AR, MA and ARIMA time series models. The problem is tested for a case study, analyzing the behaviour of the offers and bids. Also, the results obtained are studied and relevant conclusions are presented.Es la versión aceptada del documento. Se puede consultar la versión final en el DOI 10.1109/PTC.2015.723244

O mercado de trabalho argentino na pós-conversibilidade (2003-2015): entre a crise neoliberal e os limites estruturais da economia

The article proposes to study the evolution of the Argentine labor market in the post-convertibility period, as well as its main transformations. To do this, different variables are analyzed (employment, salary, employment relationship quality, and urban informal sector evolution), based on considering land rent and the productivity lag of the Argentine economy as the structural determinants of the accumulation process of Argentine capital. The results show a significant reversal of the trends that operated since the mid -1970s, particularly toward the 1990s, so that the latter period ended with substantially better levels. However, this recovery was stagnated in 2011-2012. From a long-term perspective, this shows a working population affected by a differentiation in their reproductive conditions, much deeper than those in the past.El artículo se propone estudiar la evolución del mercado laboral argentino en la posconvertibilidad, así como sus principales transformaciones. Para ello, se analizan diferentes variables (empleo, salario, calidad del vínculo laboral, evolución del sector informal urbano) a partir de considerar a la renta de la tierra y el rezago de productividad de la economía argentina como los determinantes estructurales del proceso de acumulación de capital argentino. Entre los resultados se observa una importante reversión de las tendencias que operaron desde mediados de la década de 1970, particularmente hacia la de 1990, de modo que el periodo se cerró con niveles sustancialmente mejores. No obstante, dicha recuperación se estancó hacia 2011 - 2012, lo cual, desde una perspectiva de largo plazo, muestra una población trabajadora atravesada por una diferenciación en sus condiciones de reproducción, mucho más profundas que las existentes en el pasado.O artigo propõe estudar a evolução do mercado de trabalho argentino na pós-conversibilidade, bem como suas principais transformações. Para isso, analisam-se diferentes variáveis (emprego, salário, qualidade do vínculo empregatício, evolução do setor informal urbano), considerando a renda da terra e a defasagem de produtividade da economia argentina como determinantes estruturais do processo de acumulação de capital argentino. Os resultados mostram uma reversão significativa das tendências que operaram desde meados da década de 1970, particularmente até a década de 1990, de modo que o período fechou com níveis substancialmente melhores. No entanto, esta recuperação estagnou no período 2011-2012, que, a partir de uma perspetiva de longo prazo, mostra uma população trabalhadora atravessada por uma diferenciação nas suas condições de reprodução, muito mais profunda do que as que existiam no passado