Calefacción de viviendas por guardapolvos radiantes

Tesis (Ingeniero Constructor)El guardapolvo radiante es un sistema de calefacción basado en la circulación de agua caliente através de las tuberías que forman su estructura, la que cede la energía calórica al recirÁo mediante los fenómenos físicos de radiación y convección. Es un sistema de fácil dimensionamiento, de reducido costo y con las mismas cualidades de los sistemas actuales. En el desarrollo del presente trabajo se expone de forma clara los conceptos básicos de calefacción, la normativa vigente y la forma de distribución de los sistemas actuales, por otra parte, se detalla su estructura, los elementos complementarios, el calculo térmico de la vivienda a calefaccionar y la energía calórica cedida por la tubería al ambiente, para concluir con un estudio técnico económico entre el guardapolvo radiante versus una opción equivalente, los radiadores, donde los costos presentan variaciones importantes. El guardapolvo radiante depende de dos variables, el perímetro del recinto y el requerimiento energético del mismo. El primero determina la longitud del guardapolvo y el segundo la energía calórica que necesita la vivienda, ambas variables determinan la cantidad de tuberías que integran el sistema. Por otra parte, la temperatura de equilibrio sólo se logra cuando el recinto de mayor requerimiento energético alcanza su temperatura óptima. Como principales ventajas del sistema se destacan su gran adaptabilidad, el ahorro inducido en el tiempo y una proximidad ideal a la curva de calefacción. Por ultimo, el guardapolvo radiante como todo sistema de calefacción presenta debilidades, tales como, una puesta en servicio lenta, no es recomendable para grandes espacios o para recintos que requieran más de dos servicios distribución, debido a su elevado costo de implementación.The dust cover is a radiant heating system based on the movement of hot water through pipes that form its structure, which gave the heat energy to the site through the physical phenomena of radiation and convection. It is a system for easy sizing of reduced cost and with the same qualities of current systems. In undertaking this work sets out in c1ear the basic concepts of heating, the current rules and form of distribution of current systems, moreover, detailing its structure, elements complementary, the Thermal calculation of housing heating and heat energy transferred by pipeline to the environment, concluding with a technical study from economic duster cover radiant versus an option equivalent, the radiators, where costs have significant variations The duster cover radiant depends on two variables, the perimeter of the compound and the order of the same energy. The first determines the length of the canopy and the second heat energy it needs housing, both variables determine the amount of pipes that make up the system. On the other hand, the temperature balance is achieved only when the compound of higher energy demand reaches its optimum temperature As a majar system advantages are its high adaptability, the savings in time and induced an ideal proximity to the heating curve Finally, the duster cover radiant heating system as a whole presents weaknesses, such as an in-service slow, it is not recommended for larger spaces or enclosures that require more than two distribution services, due to its high cost of implementatio

Intertemporal and Spatial Location of Disposal Facilities

The optimal capacity and location of a sequence of landfills are studied, and the interactions between both decisions are pointed out. Deciding the capacity of a landfill has some spatial implications, because it effects the feasible region for the rest of the landfills, and some temporal implications because the capacity determines the lifetime of the landfill and hence the instant of time where the next landfills will need to be constructed. Some general mathematical properties of the solution are provided and interpreted from an economic point of view. The resulting problem turns out to be nonconvex and, therefore, it can not be solved by conventional optimization techniques. Some global optimization methods are used to solve the problem in a particular case to illustrate the behavior of the solution depending on the parameter values.Landfilling, Optimal Capacity, Optimal Location, Global Optimization.

On Sevillian guilds towards the end of the 11th century

In the third decade of the 20th century, Lévi-Provençal discovered an Arab manuscript by the ishbīlī Ibn cAbdūn, that dealt with the commercial and artisan practices in Seville at the end of the 11th century. In the document there were references to the offices and personages who had to perform certain functions in various professions. From this manuscript, Lévi-Provençal deduced the existence of 11th-century Islamic guilds in Seville. This idea was assumed by Spanish historians, even up until the final decade of the 20th century. In the present article, the basis which sustained such an idea is analyzed with particular emphasis on the treatise by Ibn cAbdūn, since this is the only work that describes the economy of Seville at the time of Classic Islam (before the 12th century), and since this is the principal historical source cited by recent historians as a guarantee of the existence of Sevillian guilds during the Classic Islam; however, other manuscripts of Islamic authors of al-Andalus, and articles of contemporary authors are also taken into account. The result of our investigation disproves the existence of 11th century Islamic guilds in SevilleEn la tercera década del siglo XX Lévi-Proveçal descubrió un manuscrito árabe del išbīlī Ibn cAbdūn, donde se tratan las prácticas comerciales y artesanales en Sevilla a finales del siglo XI. En él hay referencias a los oficios y a personajes que debían cumplir determinadas funciones sobre la profesión. De ahí Lévi-Provençal dedujo la existencia de gremios islámicos en Sevilla. Esta idea resultó ser sugestiva y fue asumida por historiadores españoles del siglo XX, incluso en la década final de ese siglo. En el presente artículo se analizan las bases que sustentaron tal idea, haciéndose especial hincapié en el Tratado de Ibn cAbdūn por ser la única obra que se refiere a la economía de Sevilla en la época del islam clásico (antes del siglo XII) y la principal fuente histórica mencionada por dichos historiadores recientes como garantía de la existencia de gremios sevillanos durante el islam; sin embargo, también se tendrán en cuenta otros manuscritos de autores islámicos de al-Andalus y artículos de autores contemporáneos. El resultado de nuestra investigación refuta la existencia de gremios islámicos en la Sevilla del siglo X

The role of environmental accounting in organizational change: An exploration of Spanish companies

Critique originated by earlier theorization of environmental accounting, as a way of building environmentalist visibility of business, led Gray et al., to study environmental accounting in the dynamics of organizational change. They concluded that environmental accounting is being used to ``negotiate the conception of the environment'' by companies that have not significantly changed. In order to investigate whether Gray et al.'s model and conclusions apply to a different cultural context, we have conducted nine case studies in Spain. We found that Spanish organizations are not truly changing their conventional perception of the environment, even in those cases where generalized structural and organizational changes are taking place. Moreover, the use of environmental accounting is coupled with an attempt to negotiate and control the environmental agenda

Presencia de los hombres en redes de Investigación de género en el ámbito de comunicación en España

El objetivo de este trabajo es conocer la productividad y colaboración científica de los autores que han publicado trabajos sobre género en las revistas españolas de comunicación, prestando especial atención al rol desempeñado por los hombres. Se ha analizado la red de citaciones con el fin de identificar la red de investigadores y la participación de los hombres en la misma. La hipótesis de la que se parte es que los hombres tienen un papel secundario en las comunidades científicas que investigan sobre género en el área de comunicación. Se aplican metodologías procedentes del análisis de redes sociales. La información extraída ha sido analizada con el programa Ucinet. Se comprueba que los hombres tienen un rol marginal en la red y que las mujeres tienden a citar a otras mujeres en sus publicaciones.The purpose of this paper is to learn about the scientific productivity and collaboration of authors who have published papers on gender in Spanish communication journals by paying special attention to the role played by men. The citation network was analysed in order to identify the researchers network and the participation of men therein. The hypotesis put forward is that men have a secondary role in scientific communities that research gender in the communication field. Methodologies from the analysis of social network were applied. The information extracted was analysed using Ucinet software. It was confirmed that men have a marginal role in the network and that women tend to cite other women in their publication

Standardization Framework for Sustainability from Circular Economy 4.0

The circular economy (CE) is widely known as a way to implement and achieve sustainability, mainly due to its contribution towards the separation of biological and technical nutrients under cyclic industrial metabolism. The incorporation of the principles of the CE in the links of the value chain of the various sectors of the economy strives to ensure circularity, safety, and efficiency. The framework proposed is aligned with the goals of the 2030 Agenda for Sustainable Development regarding the orientation towards the mitigation and regeneration of the metabolic rift by considering a double perspective. Firstly, it strives to conceptualize the CE as a paradigm of sustainability. Its principles are established, and its techniques and tools are organized into two frameworks oriented towards causes (cradle to cradle) and effects (life cycle assessment), and these are structured under the three pillars of sustainability, for their projection within the proposed framework. Secondly, a framework is established to facilitate the implementation of the CE with the use of standards, which constitute the requirements, tools, and indicators to control each life cycle phase, and of key enabling technologies (KETs) that add circular value 4.0 to the socio-ecological transition

Copying, Superstars, and Artistic Creation

We provide a new perspective on the impact of unauthorized copying and copy levies on artistic creation. Our analysis emphasizes three important aspects of artistic markets: the predominance of superstars, the dynamics of talent sorting, and the importance of promotion expenditures. In the short run, piracy reduces superstars’ earnings and market share, and increases the number of niche and young artists. From a dynamic perspective, piracy may help more young artists start their careers, thereby increasing the number of highly talented artists in the long run. The long run impact on artistic creation of levies on copy equipment may crucially depend on whether their yields primarily accrue to superstars or are allocated to help young artists.artistic creation, superstars, private copy, piracy, levies