Análise de transferência térmica de tubos com superfícies estendidas com desenho fractal

1 recurso en línea (páginas 31-37).Os permutadores de calor estão conformados por tubos com superfícies estendidas, com o propósito de melhorar a transferência de calor entre dois meios, que podem ser um sólido e um líquido em movimento. No presente trabalho expõe-se o desenho que se realizou de um tubo de superfície estendida com geometria fractal, correspondente ao floco de Koch e a curva de Cesaro, com a ferramenta computacional CAD, para logo realizar a análise por elementos finitos CAE e verificar o comportamento térmico do tubo desenhado. Logrou-se obter como resultado reduzir o tempo de transferência de calor e aumentar o fluxo de calor no sistema da seguinte maneira: para tubo liso, 250 W/m2; para superfície de Koch, 500 W/m2; para seis aletas, 1450 W/m2, e, finalmente, para curva de Cesaro, 3600 W/m2. Tudo isto, permitiu evidenciar os limites do desenho e as vantagens que podem chegar a terem relação a sua implementação em maquinarias como condensadores, permutadores de calor e caldeiras.Heat exchangers are formed by tubes with extended surfaces that improve the transfer of heat between two media (e.g., a solid and a liquid in motion). This paper presents the design of an extended surface tube with fractal geometry, corresponding to the Koch snowflake and the Cesaro curve. For the design, we used the CAD computational tool, and afterwards we performed the CAE finite element analysis and verified the thermal behavior of the designed tube. We were able to reduce the heat transfer time and increase the heat flow in the system in the following manner: for smooth tube, 250 W/m2; for Koch surface, 500 W/m2; for six fins, 1450 W/ m2; and for Cesaro curve, 3600 W/m2. These results demonstrate the limits of the design and the advantages of its implementation in machinery such as condensers, heat exchangers, and boilers.Los intercambiadores de calor están conformados por tubos con superficies extendidas, con el propósito de mejorar la transferencia de calor entre dos medios, que pueden ser un sólido y un líquido en movimiento. En el presente trabajo se expone el diseño que se llevó a cabo de un tubo de superficie extendida con geometría fractal, correspondiente al copo de Koch y la curva de Cesaro, con la herramienta computacional CAD, para luego realizar el análisis por elementos finitos CAE y verificar el comportamiento térmico del tubo diseñado. Se logró obtener como resultado reducir el tiempo de transferencia de calor y aumentar el flujo de calor en el sistema del modo siguiente: para tubo liso, 250 W/m2; para superficie de Koch, 500 W/m2; para seis aletas, 1450 W/m2, y, finalmente, para curva de Cesaro, 3600 W/m2. Todo ello, permitió evidenciar los límites del diseño y las ventajas que pueden llegar a tener respecto a su implementación en maquinarias como condensadores, intercambiadores de calor y calderas.Bibliografía: páginas 36-37

Thermal transfer analysis of tubes with extended surface with fractal design

Heat exchangers are formed by tubes with extended surfaces that improve the transfer of heat between two media (e.g., a solid and a liquid in motion). This paper presents the design of an extended surface tube with fractal geometry, corresponding to the Koch snowflake and the Cesaro curve. For the design, we used the CAD computational tool, and afterwards we performed the CAE finite element analysis and verified the thermal behavior of the designed tube. We were able to reduce the heat transfer time and increase the heat flow in the system in the following manner: for smooth tube, 250 W/m2; for Koch surface, 500 W/m2; for six fins, 1450 W/m2; and for Cesaro curve, 3600 W/m2. These results demonstrate the limits of the design and the advantages of its implementation in machinery such as condensers, heat exchangers, and boilers

Pasado, presente y futuro de los estudios de turismo en la universidad española

La nueva Universidad Española (esa del Plan Bolonia) de la que llevamos hablando hace ya algunos años, es cada vez más realidad del presente y menos proyecto del futuro. En muy pocos meses, todos los planes de estudio actuales y, por tanto, también el que posibilita la obtención del Título de Diplomado en Turismo, dejarán paso a los nuevos Títulos de Grado. Por su parte, los postgrados son ya una realidad que viven a diario muchos alumnos de nuestras universidades. En este escenario de cambio real de enfoque, en el que habrá que diseñar forzosamente nuevas estrategias y tácticas para conseguir la formación adecuada de los graduados y postgraduados en turismo, los autores de este trabajo quieren ser fieles a las enseñanzas que recibieron en aquella universidad que ahora estamos dejando atrás; y, de esta forma, mirar al pasado y analizar el presente, como receta necesaria para diseñar una correcta estrategia de futuro. Es por ello que nos ha parecido interesante presentar en este trabajo cuál ha sido la evolución de los estudios de turismo en nuestro país. El recuerdo del pasado comenzará con los orígenes de estos estudios en las instituciones privadas, y el largo proceso que los llevó a estar incluidos en el catálogo de enseñanzas universitarias oficiales. Posteriormente analizaremos el presente de la Diplomatura en Turismo en la universidad española, y, por último, aportaremos todos aquellos indicios que poseemos, más o menos certeros, sobre ese nuevo horizonte que se abrirá de forma general, más allá de las lógicas avanzadillas, con los nuevos estudios de Grado, Máster y Doctorado en Turismo.The new Spanish University (referred to the Bologna Plan), which we have been speaking for a few years ago, is becoming more and more a reality and less a future project. In very few months, all current curriculums in the Spanish University and, therefore, that one which makes possible to obtain the degree of Bachelor in Tourism, it will give way the new degree. Meanwhile, postgraduates are now a reality that many students live daily from our universities. In this scenario of real change, in which would be necessary design new strategies and tactics to get the proper training of graduates and postgraduates in tourism, the authors of this paper want to be faithful in relation with the teachings they received at the university, and thus look at to the past and analyze the present look, like a neccesary prescription for drawing a correct strategy for the future. That is why we have been interested in presenting the evolution of studies of tourism in our country. The memory of the past will start with the origins of these studies in private institutions, and the long process that led them to be included in the list of official university educations. Later, we will analyze the present of the degree of Bachelor in Tourism in the Spanish University, and finally we will contribute with the whole evidence that we possess, more or less accurate, on this new horizon that will be opened in general with new degrees, Master and Doctorate in Tourism

Technical note: A mobile collaborative workspace to assist forensic experts in disaster victim identification scenarios

Integrated approaches to disaster victim identification (DVI) management have led to a need for technologies to improve interaction among parties involved in post-mortem (PM) and ante-mortem (AM) data collection through better communication and coordination. Mobile Forensic Workspace© (MFW) is a collaborative mobile system that not only facilitates the systematic collection of high-quality data, but also allows DVI professionals to coordinate activities and exchange data through secure real-time communication at major disaster scenarios in accordance with security, privacy and legal protocols. MFW is adaptable to any communication format (text, voice calls, photographs, etc.) and is dynamically self-reconfigurable when connectivity problems arise. It also allows data integration and backup through secure communication channels between local and remote servers. The feasibility of the system has been demonstrated through implementation of MFW on the iOS platform for iPhone, iPod Touch and iPad terminals. A further strength of MFW is that it provides out-of-the-box support for INTERPOL DVI forms. The application of information and communication technologies for DVI was shown to be useful in improving DVI management by enhancing the quality of data collection and enabling non-Internet dependent real-time data sharing and communication

Design of longitudinal finned tubes adjusted with the Cesàro curve

This paper proposes a process of higher heat transfer efficiency, through a fractal design over Cesàro curve as an extend surface for an exchange tube. Our designs yielded better results applying finite element analysis compared with the smooth surface commonly used in the industry. This new adaptation can be oriented toward applications involving gases and viscous liquids, for devices such as motors, boilers and dissipaters, among others

A Communication Model to Integrate the Request-Response and the Publish-Subscribe Paradigms into Ubiquitous Systems

The Request-Response (RR) paradigm is widely used in ubiquitous systems to exchange information in a secure, reliable and timely manner. Nonetheless, there is also an emerging need for adopting the Publish-Subscribe (PubSub) paradigm in this kind of systems, due to the advantages that this paradigm offers in supporting mobility by means of asynchronous, non-blocking and one-to-many message distribution semantics for event notification. This paper analyzes the strengths and weaknesses of both the RR and PubSub paradigms to support communications in ubiquitous systems and proposes an abstract communication model in order to enable their seamless integration. Thus, developers will be focused on communication semantics and the required quality properties, rather than be concerned about specific communication mechanisms. The aim is to provide developers with abstractions intended to decrease the complexity of integrating different communication paradigms commonly needed in ubiquitous systems. The proposal has been applied to implement a middleware and a real home automation system to show its applicability and benefits.This research work is funded by the Project P10-TIC-6600 granted by the Andalusian Regional Government, and the Project 20F2/36 granted by CEI-BioTIC Granada. This work has also been partially supported by the “Contrato-Programa, Facultad de Educacin y Humanidades de Ceuta 2010-2012” of the University of Granada

La Alta Velocidad Española : un viaje en el tiempo a través del turismo cultural, la tecnología y el progreso

La Alta Velocidad Española (AVE) se ha configurado, desde la inauguración, en 1992, de la línea Madrid-Sevilla, como el medio de transporte puntero de la última década del siglo XX y de los albores del XXI. El tren de alta velocidad ha revolucionado el turismo cultural y de negocios de los destinos como atractivo de su proyección turística. Este medio de transporte ha transformado las infraestructuras de las estaciones ferroviarias y, por ende, el trazado urbano de las ciudades. Así, Andalucía cuenta con más de 2.000 bienes inmuebles (monumentos, jardines, conjuntos y sitios históricos, zonas arqueológicas y museos) de interés cultural integrados en el Patrimonio Histórico Español. El AVE ha supuesto un instrumento de cohesión territorial, fundamentalmente, para la zona sur de España, pero también para la Costa Mediterránea y Galicia con la apertura de las líneas Madrid-Valencia, Madrid-Barcelona, Madrid-Málaga y La Coruña-Orense. La rapidez, el aumento de viajeros, el acercamiento de culturas, la descongestión de la red viaria y la escasa nocividad con el medio ambiente son las principales ventajas de la alta velocidad, aunque no está exenta de inconvenientes como el precio y el retraso en la apertura de las nuevas líneas programadas por su alto coste.The Spanish high speed train has been formed, from the opening, in 1992, of the railway route Madrid-Sevilla, as the way of top transport of last decade of the 20th century and at dawn of the XXIst. The high-speed train has revolutionized the cultural and business tourism of the destinations as attraction of his tourist projection. This way of transport has transformed the infrastructures of the railway stations and, therefore, the urban design of the cities. So Andalucía has more than 2.000 real estate (monuments, gardens, sets and historical sites, archaeological zones and museums) of cultural interest joined the Historical Spanish Heritage. The AVE has supposed an instrument of territorial cohesion, fundamentally, for the south zone of Spain, but also for the Mediterranean coast and Galicia with the opening of the railway routes Madrid- Valencia, Madrid-Barcelona, Madrid-Malaga and La Coruña-Orense. The speed, the travelers' increase, the rapprochement of cultures, the relieving of roads and the little noxiousness with the environment are the principal advantages of the high speed, though it is not exempt from disadvantages as the price and the delay in the opening of the new lines programmed by his high cost

Sleep disorders as a result of the COVID-19 Pandemic

Las complicaciones respiratorias por la COVID-19 pueden llevar a la muerte, por lo que, dentro de las políticas de protección para evitar los contagios masivos, se han sugerido estrategias de cuarentena y confinamiento en muchos países, que han originado alteraciones en la salud mental y el sueño. A través de la siguiente revisión narrativa se pretende sistematizar los hallazgos más significativos en cuanto a la presencia de insomnio en pacientes hospitalizados con COVID-19, y de personas sanas que han estado sometidas a confinamiento como medida preventiva. Las condiciones propias de la enfermedad han hecho que los pacientes desarrollen insomnio, lo que puede empeorar su estado de salud y alterar su sistema inmunológico. Para las personas sanas en cuarentena los cambios en el estilo de vida, el miedo a contraer la enfermedad, la edad joven, el sexo femenino, los antecedentes de enfermedades mentales y una menor capacidad de afrontamiento al estrés parecen ser factores de riesgo para el insomnio. Al igual que la implementación de medidas epidemiológicas de cuidado y prevención contra el COVID-19, se debe tener en consideración promover la higiene del sueño como una estrategia de afrontamiento integral contra esta pandemia.Respiratory complications from COVID-19 can lead to death. For this reason, public health measures to curb the spread of the disease such as quarantine and other confinement strategies have been proposed in several countries, resulting in mental health and sleep disorders. We carried out a narrative review to systematize the most significant findings regarding insomnia in hospitalized patients with COVID-19, and in healthy persons who have been under confinement as a preventive measure. COVID-19-related conditions have caused insomnia in patients, which can alter the immune system and have a negative effect on health. For healthy people in quarantine, lifestyle changes, fear of becoming infected, young age, female gender, history of mental illness and reduced ability to cope with stress appear to be risk factors for insomnia. As well as the implementation of epidemiological and preventive measures, sleep hygiene should be promoted as a comprehensive coping strategy against the COVID-19 pandemic

Variables que influyen en la fijación de precios en el transporte aéreo : el caso de la ruta Madrid-Barcelona

El objetivo del presente trabajo es analizar el efecto de una serie de variables sobre la fijación de precios en el transporte aéreo. A tal fin se analizan las variaciones de precios en función de variables como las estrategias de las diversas compañías que cubren la ruta, la cercanía a la fecha de salida, el día de la semana o el horario de salida del vuelo. Para el análisis se han utilizado datos de la ruta Madrid-Barcelona, la más frecuentada de las rutas aéreas europeas en la fecha de obtención de datos.This paper purpose is to examine the effect that some variables have on the prices setting in air transport. The prices variation is analysed related to variables as air transport companies strategies, the time to the flight departure, the day of the week or the flight schedule. The Madrid-Barcelona air route has been chosen because it is the more frequented air route in Europe

Características del bienestar psicológico en jóvenes universitarios en el marco aislamiento preventivo por COVID-19

El bienestar psicológico se caracteriza por generar un fuerte sentido de vida y un proceso de autoevaluación. Para evaluarlo se utiliza el test de Bienestar Psicológico Carol Ryff, el cual fue digitalizado para ser enviado a estudiantes universitarios, controlando el número de respuestas por test como el control en su contenido, hecho desde un enfoque cuantitativo, con un diseño no experimental y alcance correlacional, encontrando en bienestar psicológico (BP) 71,9 % (527) de los participantes tiene BP Alto, 25,4 % (186 estudiantes) en moderado, 1,6 % (12 estudiantes) baja y alta correspondiente al 1,1 % (8 estudiantes). Los resultados indican que las relaciones entre bienestar psicológico, semestre académico y sexo son bajas o muy bajas y no tienen ni ejercen influencia alguna sobre los demás en el contexto de aislamiento y pandemia dada por el COVID-19.Psychological well-being is characterized by generating a strong sense of life and a self-evaluation process. To evaluate it the Carol Ryff psychological well-being test is used, which was digitized to be sent to university students, controlling the number of responses per test such as the control in its content, done from a quantitative approach, with a nonexperimental design and correlational scope. The findings show psychological well-being (BP) 71.9 % (527) of the participants have High BP, 25.4 % (186 students) in moderate, 1.6 % (12 students) low and high corresponding to 1.1 % (8 students). The results indicate that the relationships between psychological well-being, academic semester and sex are low or very low and do not have or exert any influence on the others in the context isolation and pandemic given by COVI D-19