24,498 research outputs found

    Risk analysis of LPG tanks at the wildland-urban interface

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    In areas of wildland-urban interface (WUI), especially residential developments, it is very common to see liquefied petroleum gas (LPG) tanks, particularly with a higher ratio of propane, in surface installations serving homes. The most common tanks are between 1 and 5 m3 of capacity, but smaller ones of less than 1 m3 are more frequent. In case of accident, installations may be subject to fires and explosions, especially in those circumstances where legal and normative requirements allow very close exposure to flames from vegetable fuel near LPG tanks. In this project, it is intended to do a comprehensive diagnosis of the problem, addressing the compilation of information on real risk scenarios in historical fires. First, a preliminary presentation of the properties and characteristics of liquefied petroleum gas will be exposed. Its physical and chemical properties, production methodology, pressure and temperature diagrams and important considerations will be defined when using this type of substances in a storage tank of a certain volume. Next, a review of the situation of the existence of LPG tanks in the urban forest interfaces will be exposed. In this case, the main accidents caused by problems with the storage of LPG will be analyzed taking into account the relevance of BLEVE events in this type of incidents. To do this, the main scenarios that could take place in the event of a fire will be presented. Next, the existing legislation on the storage of LPG in these environments in some Mediterranean countries will be studied. In order to develop a comprehensive analysis, the main safety measures and distances will be considered, as well as the awareness of the possibility of vegetation material in the vicinity of LPG storage tanks, which is the main problem that will arise in a possible BLEVE scenario in case of fire. To finalize and facilitate understanding, a comparative table will be included with the aim of visualizing the main advantages and legislative deficiencies between the different countries. Following, the state of the art in terms of modelling LPG accidents at the WUI will be reviewed. Trying to simulate and predict this type of scenarios, it will see the models normally chosen to obtain the tolerable values selected and the answers obtained in each case. Finally, several fire scenarios will be simulated by means of a CFD tool (FDS, Fire Dynamics Simulator). In these simulations, the wind velocity and the distance of the combustible vegetal mass to the tank will be controlled in a WUI fire in which there is a tank of fixed dimensions. The temperature and the heat flow in each of the scenarios will be obtained, and the differences among the location of the sensors and the characteristics of the scenario will be analyzed. As a conclusion, it has been observed that there is a great amount of variables that are not contemplated by the regulatory organisms and that the existing legislation does not guarantee the safety of the population in this type of environment. From the simulations results, variables as temperature should be studied for further characterizations

    The drift of public spending towards the elderly: A generational analysis of the trend of public policies in Spain

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    The tendency for public welfare spending to be increasingly aimed at the elderly has been pointed out for the US and other developed countries. While population ageing is a common trend, it is not obvious why the shift in spending exceeds the trend in ageing, or why per capita spending on the elderly increases. We show that this is the case in Spain, identify the losers from this development, discuss the policies that underlie this trend, and propose adjustments based on Musgrave’s fixed proportions rule as an inter-generationally fair distribution.Intergenerational equity, Musgrave’s rule, Spanish social policy and ageing

    Evolution of the influence of geography on the location of production in Spain (1930-2005)

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    In this paper, we investigate the relative importance of geographic features on the location of production in Spain. Specifically, we want to quantify how much of the spatial pattern of GDP can be attributed to only exoge-nous first nature elements (physical and political geography) and how much can be derived from endogenous second nature factors (man-made agglomeration economies). In order to disentangle both effects empiri-cally, and to learn how they are interrelated, we control for second nature. We use a methodology based on an analysis of variance (ANOVA), which is applied to a panel of 47 Spanish provinces in the period 1930-2005. We demonstrate that results can be biased if spatial autocorrelation and spatial heterogeneity, as well as multicollinearity and endogeneity, are not prop-erly taken into account. In the Spanish case, we detect strong spatial het-erogeneity in the form of two main clusters. As expected, gross second na-ture forces are more important than net natural advantages, though their effects range from about 55% in the hinterland to 80% in the coast.Agglomeration, Geography, Spatial Heterogeneity, Endogeneity, Spanish Regions

    Student interactions in online discussion forums: their perception on learning with business simulation games

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    Digital technology offers new teaching methods with controversial results over learning. They allow students to develop a more active participation in their learning process although it does not always drive to unequivocal better learning outcomes. This study aims to offer additional evidence on the contribution of business simulation games to students' learning outcomes, considering student interactions in online discussion forums. We conducted a qualitative research with the online discussion forums of 5 different courses at bachelor and master levels, which involves 41 students' teams. The final sample was composed of 3681 messages posted by the students. The results reveal that some generic and specific managerial skills exert a positive influence on learning outcomes. Students mostly highlighted teamwork, decision-making, information processing, reaching agreements, and dealing with uncertainty as the most relevant contributions of the game towards their learning. These results have instructional and pedagogical implications for determining the best way to enhance students' motivation and learning outcomes when using digital technology methods, which involves recommendations that affect their design and monitoring

    A new way of teaching different subjects in a foreign language in the Building Engineering Degree at the Universidad Politécnica.

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    The European Union has been promoting linguistic diversity for many years as one of its main educational goals. This is an element that facilitates student mobility and student exchanges between different universities and countries and enriches the education of young undergraduates. In particular, a higher degree of competence in the English language is becoming essential for engineers, architects and researchers in general, as English has become the lingua franca that opens up horizons to internationalisation and the transfer of knowledge in today’s world. Many experts point to the Integrated Approach to Contents and Foreign Languages System as being an option that has certain benefits over the traditional method of teaching a second language that is exclusively based on specific subjects. This system advocates teaching the different subjects in the syllabus in a language other than one’s mother tongue, without prioritising knowledge of the language over the subject. This was the idea that in the 2009/10 academic year gave rise to the Second Language Integration Programme (SLI Programme) at the Escuela Arquitectura Técnica in the Universidad Politécnica Madrid (EUATM-UPM), just at the beginning of the tuition of the new Building Engineering Degree, which had been adapted to the European Higher Education Area (EHEA) model. This programme is an interdisciplinary initiative for the set of subjects taught during the semester and is coordinated through the Assistant Director Office for Educational Innovation. The SLI Programme has a dual goal; to familiarise students with the specific English terminology of the subject being taught, and at the same time improve their communication skills in English. A total of thirty lecturers are taking part in the teaching of eleven first year subjects and twelve in the second year, with around 120 students who have voluntarily enrolled in a special group in each semester. During the 2010/2011 academic year the degree of acceptance and the results of the SLI Programme have been monitored. Tools have been designed to aid interdisciplinary coordination and to analyse satisfaction, such as coordination records and surveys. The results currently available refer to the first and second year and are divided into specific aspects of the different subjects involved and into general aspects of the ongoing experience
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