4 resultados para autothermal reforming

em Helda - Digital Repository of University of Helsinki


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aerosol particles deteriorate air quality, atmospheric visibility and our health. They affect the Earth s climate by absorbing and scattering sunlight, forming clouds, and also via several feed-back mechanisms. The net effect on the radiative balance is negative, i.e. cooling, which means that particles counteract the effect of greenhouse gases. However, particles are one of the poorly known pieces in the climate puzzle. Some of the airborne particles are natural, some anthropogenic; some enter the atmosphere in particle form, while others form by gas-to-particle conversion. Unless the sources and dynamical processes shaping the particle population are quantified, they cannot be incorporated into climate models. The molecular level understanding of new particle formation is still inadequate, mainly due to the lack of suitable measurement techniques to detect the smallest particles and their precursors. This thesis has contributed to our ability to measure newly formed particles. Three new condensation particle counter applications for measuring the concentration of nano-particles were developed. The suitability of the methods for detecting both charged and electrically neutral particles and molecular clusters as small as 1 nm in diameter was thoroughly tested both in laboratory and field conditions. It was shown that condensation particle counting has reached the size scale of individual molecules, and besides measuring the concentration they can be used for getting size information. In addition to atmospheric research, the particle counters could have various applications in other fields, especially in nanotechnology. Using the new instruments, the first continuous time series of neutral sub-3 nm particle concentrations were measured at two field sites, which represent two different kinds of environments: the boreal forest and the Atlantic coastline, both of which are known to be hot-spots for new particle formation. The contribution of ions to the total concentrations in this size range was estimated, and it could be concluded that the fraction of ions was usually minor, especially in boreal forest conditions. Since the ionization rate is connected to the amount of cosmic rays entering the atmosphere, the relative contribution of neutral to charged nucleation mechanisms extends beyond academic interest, and links the research directly to current climate debate.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

From the Finnish Art Society to the Ateneum: Fredrik Cygnaeus, Carl Gustaf Estlander and the Roles of the Art Collection My dissertation deals with the Finnish Art Society and the development of its collection in the evolving field of the visual arts from the foundation of the society in 1846 to its exhibition in the Ateneum, a palace of art that was opened to the public in Helsinki in 1888. The main questions that it addresses are why and how the collection came into being, what its purpose was and what kind of future prospects were projected for it in the rapidly evolving field of the visual arts. I have examined the subject of my study from the perspectives of institutional history, the organisation of the field of art and the history of art collections. The prisms through which I have viewed the subject are the history of museums in Europe, the written history of art, the art association movement and the organisation of art education in relation to an ideology of enlightenment. Thus the activities of the Finnish Art Society are here mirrored for the first time in a wider context and the history of its collection located on the map of European collections. My research shows that the history of the collection of the Finnish Art Society initially depended on certain players in the visual arts and their particular leanings. The most important of these custodians were two long-serving chairmen of the society, Fredrik Cygnaeus (1807 1881) and Carl Gustaf Estlander (1834 1910). When the foundations for art activities had been laid through the establishment of the society, Cygnaeus and Estlander began to plan how the field of art might be moulded so as to improve the level of training for artists and to improve the quality of the collections and the opportunities for their display. Cygnaeus campaigned for the establishment of the Finnish Fine Arts Academy, while Estlander saw opportunities to combine the visual and applied arts. The findings of my research bring new information about the history of the collection of the Finnish Art Society, its profile, the professional abilities of those who were mainly responsible for developing it and the relationship between it and plans for reforming art education. The major findings are connected with the position of the collection in the field of art at different stages of its development. Despite the central monopoly of the Finnish Art Society in the field of art, the position of the collection was closely bound up with leading players in the field of art and their personal interests. This subservience also created an impediment to its full-blown enhancement and purposeful profiling, and it remained evident for a long time when the collection was seeking its own place in the Finnish art world.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Territoriality is a central issue in indigenous peoples struggles. The territorial struggles involve struggles over the control of natural resources and over political participation and representation, but also over the perception of territorial rights and the symbolic representation of the territory. These struggles are carried through both in material and symbolic ways through recurring to different discourses and representations that provide legitimation for the territorial claims of the group. The study is located in the Northern Autonomous Atlantic Region of Nicaragua. The study concerns the territorial strategies, conceptions and practices of the indigenous people and other actors. Territorial conflicts exist between the autonomous region and the central government of Nicaragua, between mestizo settlers and indigenous people, between different indigenous groups, and between these and development agents such as conservation projects. The study focuses on how territorial discourses and representations are used to legitimate territorial control. Environmental, historical and cartographical discourses are the most important discourses recurred to. The influence of discourses and representations on the territorial practices and policies of the different actors, the links between the local struggles and global processes, and the broader structural factors impacting on the territorial struggles are also analysed. Among the structural factors are the problems related to land tenure and management and the use of natural resources, the advance of the agricultural frontier, the institutional weaknesses of the central and regional governments and the legislative processes. The territorial discourses are both recurred to in a strategic way and also grounded in local ideals and practices. The discourses have produced real effects for example in legislation, land tenure systems, political representation and environmental practices. Although the use of discourses and representations are an important power tool in territorial struggles, territorial control cannot be effectively accomplished merely through representing territorial claims in a legitimate way or through reforming legislation, as the conflicts are also largely a result of structural factors affecting the region. The fieldwork was carried out during a total of twelve months between 2000 and 2002. The research methods used were semi-structured interviews, participant observation and participatory research methods. A broad range of literary sources were also used to collect data. The study is located within the field of critical political geography with a discursive political ecology approach. It can be called a critical realist approach to the discursive analysis of indigenous territoriality.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The 1980s and the early 1990s have proved to be an important turning point in the history of the Nordic welfare states. After this breaking point, the Nordic social order has been built upon a new foundation. This study shows that the new order is mainly built upon new hierarchies and control mechanisms that have been developed consistently through economic and labour market policy measures. During the post-war period Nordic welfare states to an increasing extent created equality of opportunity and scope for agency among people. Public social services were available for all and the tax-benefit system maintained a level income distribution. During this golden era of Nordic welfare state, the scope for agency was, however, limited by social structures. Public institutions and law tended to categorize people according to their life circumstances ascribing them a predefined role. In the 1980s and 1990s this collectivist social order began to mature and it became subject to political renegotiation. Signs of a new social order in the Nordic countries have included the liberation of the financial markets, the privatizing of public functions and redefining the role of the public sector. It is now possible to reassess the ideological foundations of this new order. As a contrast to widely used political rhetoric, the foundation of the new order has not been the ideas of individual freedom or choice. Instead, the most important aim appears to have been to control and direct people to act in accordance with the rules of the market. The various levels of government and the social security system have been redirected to serve this goal. Instead of being a mechanism for redistributing income, the Nordic social security system has been geared towards creating new hierarchies on the Nordic labour markets. During the past decades, conditions for receiving income support and unemployment benefit have been tightened in all Nordic countries. As a consequence, people have been forced to accept deteriorating terms and conditions on the labour market. Country-specific variations exist, however: in sum Sweden has been most conservative, Denmark most innovative and Finland most radical in reforming labour market policy. The new hierarchies on the labour market have co-incided with slow or non-existent growth of real wages and with a strong growth of the share of capital income. Slow growth of real wages has kept inflation low and thus secured the value of capital. Societal development has thus progressed from equality of opportunity during the age of the welfare states towards a hierarchical social order where the majority of people face increasing constraints and where a fortunate minority enjoys prosperity and security.