63 resultados para HYDROSTATIC PRESSURES


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From 6 to 8 November 1982 one of the most catastrophic flash-flood events was recorded in the Eastern Pyrenees affecting Andorra and also France and Spain with rainfall accumulations exceeding 400 mm in 24 h, 44 fatalities and widespread damage. This paper aims to exhaustively document this heavy precipitation event and examines mesoscale simulations performed by the French Meso-NH non-hydrostatic atmospheric model. Large-scale simulations show the slow-evolving synoptic environment favourable for the development of a deep Atlantic cyclone which induced a strong southerly flow over the Eastern Pyrenees. From the evolution of the synoptic pattern four distinct phases have been identified during the event. The mesoscale analysis presents the second and the third phase as the most intense in terms of rainfall accumulations and highlights the interaction of the moist and conditionally unstable flows with the mountains. The presence of a SW low level jet (30 m s-1) around 1500 m also had a crucial role on focusing the precipitation over the exposed south slopes of the Eastern Pyrenees. Backward trajectories based on Eulerian on-line passive tracers indicate that the orographic uplift was the main forcing mechanism which triggered and maintained the precipitating systems more than 30 h over the Pyrenees. The moisture of the feeding flow mainly came from the Atlantic Ocean (7-9 g kg-1) and the role of the Mediterranean as a local moisture source was very limited (2-3 g kg-1) due to the high initial water vapour content of the parcels and the rapid passage over the basin along the Spanish Mediterranean coast (less than 12 h).

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This paper describes preliminary results of a qualitative case study on mobile communication conducted in an elders¿ retirement home in Toronto (Ontario, Canada) in May 2012. This is part of an international research project on the relationship between mobile communications and older people.Secondary data at a Canadian level contextualizes the case study. We focus ondemographic characteristics and on adoption and use of information and communication technologies (ICTs) broken by age.Participants in the study (21 individuals) are between 75 and 98 years of age, thereforewe can consider that the gathered evidence refers to the ¿old¿ older. Mobile phoneusers in the sample describe very specific uses of the mobile phone, while non-usersreport not facing external pressures for adopting that technology. The main channel formediated communication is the landline; in consequences mobile phones ¿when used¿ constitute an extra layer of communication. Finally, when members of the personal network of the individuals live abroad they are more prone to use Internet and Skype. We are also able to find ex-users of both mobile telephony and computers/internet who stopped using these technologies because they did not find any use for them.

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El objetivo de este trabajo fue el de evaluar la deposición transversal de caldo de las boquillas pulverizadoras de doble abanico TTJ60-11004 y TTJ60-11002 en distintas condiciones operacionales. Se utilizaron 5 muestras de cada boquilla pulverizadora siendo considerada cada unidad, una repetición. La distribución de caldo fue evaluada por medio de una mesa de evaluación de distribución construida de acuerdo con la norma ISO 56821. Se evaluó el perfil de distribución individual, la distribución volumétrica simulada de la superposición de los chorros por medio del coeficiente de variación (CV%) de los volúmenes colectados, el caudal y el ángulo de abertura de los chorros. Las condiciones operacionales fueron: presión de trabajo de 200, 300 y 400 Kpa, altura de 30, 40 y 50 cm en relación al blanco y espaciamiento entre boquillas simulados en Software (Microsoft Excel) entre 45 y 100 cm. Las boquillas presentaron perfil individual descontinuo con la mayor deposición de líquido en la región central y reducción del volumen gradual en dirección a las extremidades. El aumento de la presión promovió alargamiento del perfil y de la franja de aplicación. Las boquillas proporcionaron perfil uniforme que dependió del espaciamiento entre las boquillas, con valores menores con reducción en el espaciamiento y en presiones mayores. El caudal y el ángulo del chorro aumentaron con el incremento en la presión.

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Objetivou-se com este trabalho avaliar a distribuição de líquido da ponta de pulverização com indução de ar e jato excêntrico AIUB 8502 sob diferentes condições operacionais. Foram avaliados perfil individual, vazão, ângulo de abertura do jato, faixa de aplicação e distribuição volumétrica simulada de duas pontas AIUB 8502 nas pressões de trabalho de 200, 300, 400 e 500 kPa, altura de 30, 40 e 50 cm em relação ao alvo e espaçamento entre pontas de 30 a 100 cm. Todas as análises foram realizadas seguindo a norma ISSO 5682-1, com algumas adaptações. A ponta apresentou distribuição de líquido excêntrica com um lado descontínuo e extremidade oposta excêntrica, com queda abrupta do volume de líquido. À medida que se aumentou a altura da barra e a pressão de trabalho, alongou-se o perfil do jato. O maior número de configurações uniformes foi obtido na altura de 50 cm, decrescendo nas alturas de 40 e 30 cm. A vazão e o ângulo do jato excêntrico aumentaram com o incremento na pressão, não havendo diferença entre o ângulo do jato descontínuo e o total entre as pressões de 400 e 500 kPa e de 200 e 300 kPa.

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Objetivou-se neste trabalho avaliar a distribuição volumétrica e o espectro de gotas das pontas de pulverização de baixa deriva TTI110015, AI110015 e AVI11001 sob diferentes condições operacionais. A distribuição volumétrica foi determinada em bancada de ensaios padronizada analisando o coeficiente de variação (CV%) de uma barra simulada em computador, utilizando pressões de 200, 300 e 400 kPa, altura de 30, 40 e 50 cm em relação à bancada e espaçamento entre pontas de 40 a 100 cm. O espectro de gotas foi produzido utilizando-se apenas água como calda em um analisador de partículas em meio aquoso, nas pressões de 200, 300 e 400 kPa. Foram avaliados o DMV, a porcentagem de gotas com diâmetro inferior a 100 µm (%100 µm) e a amplitude relativa (AR). As pontas proporcionaram perfil descontínuo nas pressões de 300 e 400 kPa e uniforme a 200 kPa. Na pressão de 200 kPa, as pontas foram adequadas apenas para aplicação em faixa, e a 300 e 400 kPa, apenas para área total. Ocorreu menor CV (abaixo de 7%) com a maior pressão de trabalho e menor espaçamento entre pontas. À medida que se aumentou a pressão de trabalho, reduziu-se o DMV. As pontas TTI110015 e AI110015 em todas as pressões e a ponta AVI11001 na pressão de 200 kPa produziram gotas extremamente grossas e gotas grossas nas pressões de 300 e 400 kPa apenas para a ponta AVI11001. As pontas proporcionaram baixos valores de amplitude relativa (AR) e gotas de tamanho uniforme, bem como produziram baixa porcentagem de gotas menores que 100 µm, principalmente TTI110015 e AI110015, com menor risco de deriva.

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[spa] Para hacer frente a los riesgos relacionados con la contaminación atmosférica, es ampliamente aceptada la necesidad de instrumentos de política encaminados a reducir las emisiones. La intervención tiene por objeto reducir las conductas contaminantes y incentivar una conducta más respetuosa y el uso de tecnologías más eficientes. La Unión Europea cuenta con dos importantes mecanismos económicos para el control de emisiones a escala europea: la directiva sobre los impuestos energéticos, un instrumento de fiscalidad ambiental aprobado en 2003 que afecta el precio de los productos energéticos, y el sistema de comercio de los derechos de emisiones, introducido en 2005, que afecta directamente a la cantidad de emisiones de CO2. En 2011, la Comisión Europea propuso una nueva versión de la directiva sobre los impuestos energéticos. El objetivo principal de la propuesta es aumentar la eficacia del instrumento a través de una mayor presión fiscal sobre los productos energéticos y de coordinar este instrumento de fiscalidad medioambiental con el sistema de comercio de los derechos de emisiones, para establecer una señal de precio de CO2 coherente para todos los sectores. Sin embargo, en mayo de 2012 el Parlamento Europeo bloqueó la propuesta de la nueva versión del impuesto, y el proceso de actualización se detuvo. La preocupación principal parecía ser el efecto de dicha propuesta en la competitividad, en particular para los sectores que serían los más afectados dado el uso intensivo de los productos energéticos, como el sector del transporte. El objetivo de este estudio es analizar el efecto que la reforma de la directiva sobre los impuestos energéticos podría tener sobre el nivel de precios, en particular en los países de la Unión Europea donde esta reforma implicaría un aumento de los impuestos energéticos. Utilizando datos del proyecto “World Input-Output Database”, la principal conclusión es que el nuevo sistema de impuestos energéticos tendría un impacto muy bajo sobre los precios. Por lo tanto, dado que los precios no serían fuertemente afectados por la reforma, no habrá inconvenientes para la competitividad y implicaciones en términos de distribución, pero, por otro lado, este resultado también implica una baja capacidad de esta reforma para provocar cambios en el consumo y la producción hacia menos presiones ambientales.

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[spa] Para hacer frente a los riesgos relacionados con la contaminación atmosférica, es ampliamente aceptada la necesidad de instrumentos de política encaminados a reducir las emisiones. La intervención tiene por objeto reducir las conductas contaminantes y incentivar una conducta más respetuosa y el uso de tecnologías más eficientes. La Unión Europea cuenta con dos importantes mecanismos económicos para el control de emisiones a escala europea: la directiva sobre los impuestos energéticos, un instrumento de fiscalidad ambiental aprobado en 2003 que afecta el precio de los productos energéticos, y el sistema de comercio de los derechos de emisiones, introducido en 2005, que afecta directamente a la cantidad de emisiones de CO2. En 2011, la Comisión Europea propuso una nueva versión de la directiva sobre los impuestos energéticos. El objetivo principal de la propuesta es aumentar la eficacia del instrumento a través de una mayor presión fiscal sobre los productos energéticos y de coordinar este instrumento de fiscalidad medioambiental con el sistema de comercio de los derechos de emisiones, para establecer una señal de precio de CO2 coherente para todos los sectores. Sin embargo, en mayo de 2012 el Parlamento Europeo bloqueó la propuesta de la nueva versión del impuesto, y el proceso de actualización se detuvo. La preocupación principal parecía ser el efecto de dicha propuesta en la competitividad, en particular para los sectores que serían los más afectados dado el uso intensivo de los productos energéticos, como el sector del transporte. El objetivo de este estudio es analizar el efecto que la reforma de la directiva sobre los impuestos energéticos podría tener sobre el nivel de precios, en particular en los países de la Unión Europea donde esta reforma implicaría un aumento de los impuestos energéticos. Utilizando datos del proyecto “World Input-Output Database”, la principal conclusión es que el nuevo sistema de impuestos energéticos tendría un impacto muy bajo sobre los precios. Por lo tanto, dado que los precios no serían fuertemente afectados por la reforma, no habrá inconvenientes para la competitividad y implicaciones en términos de distribución, pero, por otro lado, este resultado también implica una baja capacidad de esta reforma para provocar cambios en el consumo y la producción hacia menos presiones ambientales.

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We have studied the effect of pressure on the structural and vibrational properties of lanthanum tritungstate La2(WO4)3. This compound crystallizes under ambient conditions in the modulated scheelite-type structure known as the α phase. We have performed x-ray diffraction and Raman scattering measurements up to a pressure of 20 GPa, as well as ab initio calculations within the framework of the density functional theory. Up to 5 GPa, the three methods provide a similar picture of the evolution under pressure of α-La2(WO4)3. At 5 GPa, we begin to observe some structural changes, and above 6 GPa we find that the x-ray patterns cannot be indexed as a single phase. However, we find that a mixture of two phases with C2/c symmetry accounts for all diffraction peaks. Our ab initio study confirms the existence of several C2/c structures, which are very close in energy in this compression range. According to our measurements, a state with medium-range order appears at pressures above 9 and 11 GPa, from x-ray diffraction and Raman experiments, respectively. Based upon our theoretical calculations we propose several high-pressure candidates with high cationic coordinations at these pressures. The compound evolves into a partially amorphous phase at pressures above 20 GPa.

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In this paper we present experimental results comparing on-line drawings for control population (left and right hand) as well as Alzheimer disease patients. The drawings have been acquired by means of a digitizing tablet, which acquires time information angles and pressures. Experimental measures based on pressure and in-air movements appear to be significantly different for both groups, even when control population performs the tasks with the non-dominant hand.

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From 6 to 8 November 1982 one of the most catastrophic flash-flood events was recorded in the Eastern Pyrenees affecting Andorra and also France and Spain with rainfall accumulations exceeding 400 mm in 24 h, 44 fatalities and widespread damage. This paper aims to exhaustively document this heavy precipitation event and examines mesoscale simulations performed by the French Meso-NH non-hydrostatic atmospheric model. Large-scale simulations show the slow-evolving synoptic environment favourable for the development of a deep Atlantic cyclone which induced a strong southerly flow over the Eastern Pyrenees. From the evolution of the synoptic pattern four distinct phases have been identified during the event. The mesoscale analysis presents the second and the third phase as the most intense in terms of rainfall accumulations and highlights the interaction of the moist and conditionally unstable flows with the mountains. The presence of a SW low level jet (30 m s-1) around 1500 m also had a crucial role on focusing the precipitation over the exposed south slopes of the Eastern Pyrenees. Backward trajectories based on Eulerian on-line passive tracers indicate that the orographic uplift was the main forcing mechanism which triggered and maintained the precipitating systems more than 30 h over the Pyrenees. The moisture of the feeding flow mainly came from the Atlantic Ocean (7-9 g kg-1) and the role of the Mediterranean as a local moisture source was very limited (2-3 g kg-1) due to the high initial water vapour content of the parcels and the rapid passage over the basin along the Spanish Mediterranean coast (less than 12 h).

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Hydrogenated microcrystalline silicon films obtained at low temperature (150-280°C) by hot wire chemical vapour deposition at two different process pressures were measured by Raman spectroscopy, X-ray diffraction (XRD) spectroscopy and photothermal deflection spectroscopy (PDS). A crystalline fraction >90% with a subgap optical absortion 10 cm -1 at 0.8 eV were obtained in films deposited at growth rates >0.8 nm/s. These films were incorporated in n-channel thin film transistors and their electrical properties were measured. The saturation mobility was 0.72 ± 0.05 cm 2/ V s and the threshold voltage around 0.2 eV. The dependence of their conductance activation energies on gate voltages were related to the properties of the material.

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Corrosion reduces the lifetime of municipal solid waste incineration (MSWI) superheater tubes more than any other cause. It can be minimized by the careful selection of those materials that are most resistant to corrosion under operating conditions. Since thousands of different materials are already known and many more are developed every year, here the selection methodology developed by Prof. Ashby of the University of Cambridge was used to evaluate the performance of different materials to be used as MSWI superheater tubes. The proposed materials can operate at steam pressures and temperatures over 40 bars and 400ºC, respectively. Two case studies are presented: one makes a balanced selection between mechanical properties and cost per thermal unit; and the other focuses on increasing tube lifetime. The balanced selection showed that AISI 410 martensitic stainless steel (wrought, hard tempered) is the best candidate with a good combination of corrosion resistance, a relatively low price (0.83-0.92 e/kg) and a good thermal conductivity (23-27 W/m K). Meanwhile, Nitronic 50/XM-19 stainless steel is the most promising candidate for longterm selection, as it presents high corrosion resistance with a relatively low price (4.86-5.14 e/kg) compared to Ni-alloys.

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El objetivo de este estudio es identificar factores que contribuyen a mantener un enfoque básicamente instrumental para enseñar los sistemas externos de representación matemáticos y lingüísticos en las primeras edades de escolarización. En el estudio han participado 123 maestros de Educación Infantil de diversos centros escolares públicos de Andalucía, Asturias, Cataluña y Navarra que han asistido a cursos de formación permanente del profesorado. El análisis cualitativo realizado se basa en grupos de discusión a partir de tópicos. Los resultados evidencian la influencia de diversos factores: el currículo de Educación Infantil; las concepciones del profesorado; las presiones entre etapas educativas; y, finalmente, la presión social. La identificación de los factores asociados a una enseñanza instrumental de los sistemas externos de representación puede entenderse como un tipo de información relevante acerca de las condiciones de la enseñanza de estos sistemas que, además, pueden servir de base para reconstruir las prácticas educativas

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Background Little is known about the types of ‘sit less, move more’ strategies that appeal to office employees, or what factors influence their use. This study assessed the uptake of strategies in Spanish university office employees engaged in an intervention, and those factors that enabled or limited strategy uptake. Methods The study used a mixed method design. Semi-structured interviews were conducted with academics and administrators (n = 12; 44 ± 12 mean SD age; 6 women) at three points across the five-month intervention, and data used to identify factors that influenced the uptake of strategies. Employees who finished the intervention then completed a survey rating (n = 88; 42 ± 8 mean SD age; 51 women) the extent to which strategies were used [never (1) to usually (4)]; additional survey items (generated from interviewee data) rated the impact of factors that enabled or limited strategy uptake [no influence (1) to very strong influence (4)]. Survey score distributions and averages were calculated and findings triangulated with interview data. Results Relative to baseline, 67% of the sample increased step counts post intervention (n = 59); 60% decreased occupational sitting (n = 53). ‘Active work tasks’ and ‘increases in walking intensity’ were the strategies most frequently used by employees (89% and 94% sometimes or usually utilised these strategies); ‘walk-talk meetings’ and ‘lunchtime walking groups’ were the least used (80% and 96% hardly ever or never utilised these strategies). ‘Sitting time and step count logging’ was the most important enabler of behaviour change (mean survey score of 3.1 ± 0.8); interviewees highlighted the motivational value of being able to view logged data through visual graphics in a dedicated website, and gain feedback on progress against set goals. ‘Screen based work’ (mean survey score of 3.2 ± 0.8) was the most significant barrier limiting the uptake of strategies. Inherent time pressures and cultural norms that dictated sedentary work practices limited the adoption of ‘walk-talk meetings’ and ‘lunch time walking groups’. Conclusions The findings provide practical insights into which strategies and influences practitioners need to target to maximise the impact of ‘sit less, move more’ occupational intervention strategies.

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The empirical literature about factors explaining local government delivery choices has traditionally focused the attention on the public or private production dilemma. However, hybrid organizational forms such as mixed public-private firms are increasingly used in several European countries. This paper makes use of survey data from Spanish municipalities to examine motivations of local governments for engaging in hybrid organizational forms. Data refer to two very relevant local services: water distribution and solid waste collection. The empirical analysis indicates that the use of mixed firms emerge as a type of pragmatically based ‘third way’ between pure public and pure private production. Indeed, local governments make use of mixed firms when cost considerations (scale economies, transaction costs and soon), financial constraints and private interests exert contradictory pressures. On the contrary, political and ideological factors do not play any significant role on the local government decision of engaging or not in joint ventures with private partners.