3 resultados para Vertical pull-out failure

em Helda - Digital Repository of University of Helsinki


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There is a growing need to understand the exchange processes of momentum, heat and mass between an urban surface and the atmosphere as they affect our quality of life. Understanding the source/sink strengths as well as the mixing mechanisms of air pollutants is particularly important due to their effects on human health and climate. This work aims to improve our understanding of these surface-atmosphere interactions based on the analysis of measurements carried out in Helsinki, Finland. The vertical exchange of momentum, heat, carbon dioxide (CO2) and aerosol particle number was measured with the eddy covariance technique at the urban measurement station SMEAR III, where the concentrations of ultrafine, accumulation mode and coarse particle numbers, nitrogen oxides (NOx), carbon monoxide (CO), ozone (O3) and sulphur dioxide (SO2) were also measured. These measurements were carried out over varying measurement periods between 2004 and 2008. In addition, black carbon mass concentration was measured at the Helsinki Metropolitan Area Council site during three campaigns in 1996-2005. Thus, the analyzed dataset covered far, the most comprehensive long-term measurements of turbulent fluxes reported in the literature from urban areas. Moreover, simultaneously measured urban air pollution concentrations and turbulent fluxes were examined for the first time. The complex measurement surrounding enabled us to study the effect of different urban covers on the exchange processes from a single point of measurement. The sensible and latent heat fluxes closely followed the intensity of solar radiation, and the sensible heat flux always exceeded the latent heat flux due to anthropogenic heat emissions and the conversion of solar radiation to direct heat in urban structures. This urban heat island effect was most evident during winter nights. The effect of land use cover was seen as increased sensible heat fluxes in more built-up areas than in areas with high vegetation cover. Both aerosol particle and CO2 exchanges were largely affected by road traffic, and the highest diurnal fluxes reached 109 m-2 s-1 and 20 µmol m-2 s-1, respectively, in the direction of the road. Local road traffic had the greatest effect on ultrafine particle concentrations, whereas meteorological variables were more important for accumulation mode and coarse particle concentrations. The measurement surroundings of the SMEAR III station served as a source for both particles and CO2, except in summer, when the vegetation uptake of CO2 exceeded the anthropogenic sources in the vegetation sector in daytime, and we observed a downward median flux of 8 µmol m-2 s-1. This work improved our understanding of the interactions between an urban surface and the atmosphere in a city located at high latitudes in a semi-continental climate. The results can be utilised in urban planning, as the fraction of vegetation cover and vehicular activity were found to be the major environmental drivers affecting most of the exchange processes. However, in order to understand these exchange and mixing processes on a city scale, more measurements above various urban surfaces accompanied by numerical modelling are required.

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The economic, political and social face of Europe has been changing rapidly in the past decades. These changes are unique in the history of Europe, but not without challenges for the nation states. The support for the European integration varies among the countries. In order to understand why certain developments or changes are perceived as threatening or as desired by different member countries, we must consider the social representations of the European integration on the national level: how the EU is represented to its citizens in media and in educational systems, particularly in the curricula and textbooks. The current study is concerned with the social representations of the European integration in the curricula and school textbooks in five European countries: France, Britain, Germany, Finland and Sweden. Besides that, the first volume of the common Franco-German history textbook was analyzed, since it has been seen as a model for a common European history textbook. As the collective representations, values and identities are dominantly mediated and imposed through media and educational systems, the national curricula and textbooks make an interesting starting point for the study of the European integration and of national and European identities. The social representations theory provides a comprehensive framework for the study of the European integration. By analyzing the curricula and history and civics textbooks of major educational publishers, the study aimed to demonstrate what is written on the European integration and how it is portrayed how the European integration is understood, made familiar and concretized in the educational context in the five European countries. To grasp the phenomenon of the European integration in the textbooks in its entirety, it was investigated from various perspectives. The two analysis methods of content analysis, the automatic analysis with ALCESTE and a more qualitative theory-driven content analysis, were carried out to give a more vivid and multifaceted picture of the object of the research. The analysis of the text was complemented with the analysis of visual material. Drawing on quantitative and qualitative methods, the contents, processes, visual images, transformations and structures of the social representations of European integration, as well as the communicative styles of the textbooks were examined. This study showed the divergent social representations of the European integration, anchored in the nation states, in the five member countries of the European Union. The social representations were constructed around different central core elements: French Europe in the French textbooks, Ambivalent Europe in the British textbooks, Influential and Unifying EU in the German textbooks, Enabling and Threatening EU in the Finnish textbooks, Sceptical EU in the Swedish textbooks and EU as a World Model in the Franco-German textbook. Some elements of the representations were shared by all countries such as peace and economic aspects of the European cooperation, whereas other elements of representations were found more frequently in some countries than in others, such as ideological, threatening or social components of the phenomenon European integration. The study also demonstrated the linkage between social representations of the EU and national and European identities. The findings of this study are applicable to the study of the European integration, to the study of education, as well as to the social representation theory.

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The four scientific articles comprising this doctoral dissertation offer new information on the presentation and construction of addiction in the mass media during the period 1968 - 2008. Diachronic surveys as well as quantitative and qualitative content analyses were undertaken to discern trends during the period in question and to investigate underlying conceptions of the problems in contemporary media presentations. The research material for the first three articles consists of a sample of 200 texts from Finland s biggest daily newspaper, Helsingin Sanomat, from the period 1968 - 2006. The fourth study examines English-language tabloid material published on the Internet in 2005 - 2008. A number of principal trends are identified. In addition to a significant increase in addiction reporting over time, the study shows that an internalisation of addiction problems took place in the media presentations under study. The phenomenon is portrayed and tackled from within the problems themselves, often from the viewpoint of the individuals concerned. The tone becomes more personal, and technical and detailed accounts are more and more frequent. Secondly, the concept of addiction is broadened. This can be dated to the 1990s. The concept undergoes a conventionalisation: it is used more frequently in a manner that is not thought to require explanation. The word riippuvuus (the closest equivalent to addiction in Finnish) was adopted more commonly in the reporting at the same time, in the 1990s. Thirdly, the results highlight individual self-governance as a superordinate principle in contemporary descriptions of addiction. If the principal demarcation in earlier texts was between us and them , it is now focused primarily on the individual s competence and ability to govern the self, to restrain and master one's behaviour. Finally, in the fourth study investigating textual constructions of female celebrities (Amy Winehouse, Britney Spears and Kate Moss) in Internet tabloids, various relations and functions of addiction problems, intoxication, body and gender were observed to function as cultural symbols. Addiction becomes a sign, or a style, that represents different significations in relation to the main characters in the tabloid stories. Tabloids, as a genre, play an important role by introducing other images of the problems than those featured in mainstream media. The study is positioned within the framework of modernity theory and its views on the need for self-reflexivity and biographies as tools for the creation and definition of the self. Traditional institutions such as the church, occupation, family etc. no longer play an important role in self-definition. This circumstance creates a need for a culture conveying stories of success and failure in relation to which the individual can position their own behaviour and life content. I propose that addiction , as a theme in media reporting, resolves the conflict that emanates from the ambivalence between the accessibility and the individualisation of consumer society, on the one hand, and the problematic behavioural patterns (addictions) that they may induce, on the other.