668 research outputs found

    Direct observation of a liquid film under a vapor environment in a pool boiling using a nanofluid

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    The existence of a liquid film separating a vapor bubble from a heated solid surface is confirmed using a nanofluid. The existence of such a liquid film had been a theoretical premise of the critical heat flux mechanism, significantly difficult to verify through experimental observations. Here, we show that a liquid film under a massive vapor bubble adheres to a heated solid surface. The liquid film comes into being trapped in a dynamic coalescence environment of nucleate bubbles, which grow and depart continuously from the heated surface. In its dryout process, the liquid film displays vapor "holes" originating from the rupture of discrete nucleating bubbles. The dryout process of the liquid film can be understood from the vaporization of rims of the holes and of smooth film region.open51

    Tritium supply and use: a key issue for the development of nuclear fusion energy

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    Full power operation of the International Thermonuclear Experimental Reactor (ITER) has been delayed and will now begin in 2035. Delays to the ITER schedule may affect the availability of tritium for subsequent fusion devices, as the global CANDU-type fission reactor fleet begins to phase out over the coming decades. This study provides an up to date account of future tritium availability by incorporating recent uncertainties over the life extension of the global CANDU fleet, as well as considering the potential impact of tritium demand by other fusion efforts. Despite the delays, our projections suggest that CANDU tritium remains sufficient to support the full operation of ITER. However, whether there is tritium available for a DEMO reactor following ITER is largely uncertain, and is subject to numerous uncontrollable externalities. Further tritium demand may come from any number of private sector “compact fusion” start-ups which have emerged in recent years, all of which aim to accelerate the development of fusion energy. If the associated technical challenges can be overcome, compact fusion programmes have the opportunity to use tritium over the next two decades whilst it is readily available, and before full power DT operation on ITER starts in 2035. Assuming a similar level of performance is achievable, a compact fusion development programme, using smaller reactors operating at lower fusion power, would require smaller quantities of tritium than the ITER programme, leaving sufficient tritium available for multiple concepts to be developed concurrently. The development of concurrent fusion concepts increases the chances of success, as it spreads the risk of failure. Additionally, if full tritium breeding capability is not expected to be demonstrated in DEMO until after 2050, an opportunity exists for compact fusion programmes to incorporate tritium breeding technology in nearer-term devices. DD start-up, which avoids the need for external tritium for reactor start-up, is dependent upon full tritium breeding capability, and may be essential for large-scale commercial roll-out of fusion energy. As such, from the standpoint of availability and use of external tritium, a compact route to fusion energy may be more advantageous, as it avoids longer-term complications and uncertainties in the future supply of tritium

    Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

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    Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD

    Storytelling in Amy Tan’s The bonesetter’s daughter: belonging and the transnationality of home in older age

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    Amy Tan’s The Bonesetter’s Daughter is a fictional account of a Chinese American woman and her mother, a first generation migrant, who is negotiating dementia in later life. Analysis of diasporic novels can provide insight into migrant belonging, especially the emotional geographies of home and emotional subjectivities of ageing that are not commonly or easily elucidated even by qualitative interviewing methods. This article examines Tan’s construction of ageing as an intergenerational, cultural and emotional process, and highlights the role of storytelling as an everyday home-making practice through which the transnationality of home in older age becomes evident

    The behaviour of repeat visitors to museums: Review and empirical findings

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    This study presents a theoretical and operational framework for analysing repeat visit to museums. Starting from the literature on repeat visit in tourism, the specificities of these cultural attractions are made explicit through a review of theoretical and applied works. Consistently with previous contributors, the paper suggests that the analysis of actual past behaviours has to be preferred to the one of attitudes. The application of proper econometric models is also remarked in order to put into account individual profiles. Information coming from three techniques is then used in an integrated way in order to provide a more comprehensive view of the phenomenon. Evidence from an ad hoc survey suggests the necessity to give a greater attention to perceived cultural value during the visit, promoting cultural events during the week and addressed to children, and taking care of those visitors that come from far places also through an integrated tourist supply. © 2013 Springer Science+Business Media Dordrecht

    La educación inclusiva frente a las desigualdades sociales: un estado de la cuestion y algunas reflexiones geograficas

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    Este artículo establece un estado de la cuestión e la educación inclusiva en el mundo y sugiere algunas reflexiones al respecto. El primer apartado recuerda las conexiones ineludibles entre las preocupaciones educativas por la educación inclusiva y las preocupaciones más generales por la desigualdad. El segundo consigna los criterios de búsqueda de las publicaciones académicas, y observa dos grandes temas en sus contenidos: sobre todo, el cambio interno de las escuelas atrae las miradas, pero en segundo plano también el entorno territorial despierta algunas inquietudes. El tercero anota los criterios de búsqueda de la documentación del Banco Mundial, la OCDE y la UNESCO. En este ámbito los simposios de la Oficina Internacional de la Educación de UNESCO revelan una interpretación dispar, aunque convergente, del concepto de educación inclusiva en las distintas regiones mundiales. Asimismo, todas las publicaciones oficiales muestran una atención prioritaria a las dinámicas internas de las escuelas, puesto que apenas algunas esbozan ciertas relaciones entre la educación inclusiva y las políticas públicas. El último apartado adelanta varios argumentos a favor de una mayor consideración de las escalas local y estatal de la educación inclusiva. Las principales razones para atender a la dimensión local provienen de la causalidad acumulativa de las privaciones sociales, de la necesidad de articular la acción de las escuelas y de la posibilidad de abrir un espacio significativo para la participación ciudadana. Asimismo, las principales razones para atender a la dimensión estatal surgen de las posibles sinergias entre la educación inclusiva y la expansión educativa (p. ej. ¿es correlativo el avance de la escolarización en los distintos ciclos escolares?) como también entre la educación inclusiva y la protección social (p. ej. ¿tienen una implicación pedagógica consistente las abundantes condiciones educativas de las transferencias sociales?

    Cross-cutting principles for planetary health education

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    Since the 2015 launch of the Rockefeller Foundation Lancet Commission on planetary health,1 an enormous groundswell of interest in planetary health education has emerged across many disciplines, institutions, and geographical regions. Advancing these global efforts in planetary health education will equip the next generation of scholars to address crucial questions in this emerging field and support the development of a community of practice. To provide a foundation for the growing interest and efforts in this field, the Planetary Health Alliance has facilitated the first attempt to create a set of principles for planetary health education that intersect education at all levels, across all scales, and in all regions of the world—ie, a set of cross-cutting principles

    UAV Downwash-Based Terrain Classification Using Wiener-Khinchin and EMD Filters

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    This work was partially funded by FCT Strategic Program UID/EEA/00066/203 of the Center of Technologies and System (CTS) of UNINOVA - Institute for the Development of new Technologies.Knowing how to identify terrain types is especially important in the autonomous navigation, mapping, decision making and detect landings areas. A recent area is in cooperation and improvement of autonomous behavior between robots. For example, an unmanned aerial vehicle (UAV) is used to identify a possible landing area or used in cooperation with other robots to navigate in unknown terrains. This paper presents a computer vision algorithm capable of identifying the terrain type where the UAV is flying, using its rotors’ downwash effect. The algorithm is a fusion between the frequency Wiener-Khinchin adapted and spatial Empirical Mode Decomposition (EMD) domains. In order to increase certainty in terrain identification, machine learning is also used. The system is validated using videos acquired onboard of a UAV with an RGB camera.authorsversionpublishe
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