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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Energetická bezpečnost pobaltských států Estonska, Lotyšska a Litvy / Energy security of the Baltic states Estonia, Latvia and Lithuania

Havel, Zdeněk January 2017 (has links)
Energy security is currently a favourite topic. It is being talked about in the context of several conflicts in Third World countries that, due to the supply of energy raw materials such as oil and gas, affect the rest of the world. For some states, however, the issue of ensuring energy security is a more vital. Some states, such as the Baltic countries - Estonia, Latvia and Lithuania, are dependent on supplies of fossil fuels from neighbouring countries. Moreover, up until recently their energy markets have not been liberalized, nor connected to the rest of the Europe. It is a well-known fact that the Russian Federation is the main supplier of these raw materials to them. Therefore, the Baltic states have been trying to reduce the influence of the Russian Federation in the Baltic region since they regained independence 26 years ago. This diploma thesis deals with the analysis of the energy security of all three Baltic countries. The thesis carefully analyses all aspects of their energy sector. It examines the historical development of the region, thanks to which we can understand the influence of the Russian Federation on the Baltics energy sector, as well as the level of international cooperation of the Baltic states with the EU in ensuring energy security. The analysis also focus on the...
272

A Case Study Evaluating the Performance of the NWP model HARMONIE in Simulating Convective Snowbands / Snökanoner över Östersjön och Bottniska Viken: En fallstudie över hur väl HARMONIE simulerar extrem nederbörd

Jungefeldt, Louise January 2020 (has links)
Convective snow bands forming over the Baltic Sea can result in heavy precipitation along the Swedish east coast. Forecasting these events well is of great importance to prevent road traffic injuries, increased pressure at hospitals and cancelled bus traffic. This thesis project aims to evaluate the performance of the high-resolution non-hydrostatic convection permitting model HIRLAM ALADIN Reasearch on Mesoscale Operational NWP In Euromed (HARMONIE) in simulating convective snow bands. Its horizontal respresentation of precipitation rates, area, placement and timing was examined in a case study of two events. The case of 2007 during the 12-14th of November, formed over the Gulf of Finland and resulted in Nynäshamn receiving ≥ 55 mm precipitation during the 37 hours long event. Areas south of this precipitation maxima also recieved heavy precipitation. The second case, 21-23rd of March 2008, formed over the Gulf of Bothnia during north-easterly  winds and resulted in a total precipitation of 10 mm at Gävle. The precipitation maxima was observed offshore, north of Gävle, with ≥ 16 mm precipiation in 34 hours. Convective snow bands were also observed over Vänern and Vättern in both cases.  HARMONIE simulated convective snow bands well in terms of intensity, timing, placement and area, in both cases, compared to datasets from radar, radar with merged gauge data and separate observational data from weather stations. Areas south of the local maxima at Nynäshamn in the case of 2007 were however overestimated by a total of 10-15 mm, most likely due to a simulated shift in wind direction during some of the most intense hours. In the case of 2008 the model also captured weak convective snow bands at Vänern and Vättern accurately in terms of precipitation area, timing and accumulated precipitation. Further case studies of snow bands are however necessary to obtain a more comprehensive view of the performance of HARMONIE.
273

Complementary governance for sustainable development in transport: The European TEN-T Core network corridors

Öberg, Maria, Nilsson, Kristina L., Johansson, Charlotta M. 21 December 2020 (has links)
When implementing major European transport corridors, such as the Core network corridors (CNC) which is a part of the European Trans-European Network for Transports (TEN-T), the number of stakeholders affected is huge. A governance framework for the CNC’s implementation was introduced in EU Regulation No. 1315/2013, and is now being enacted. Sustainable development and stakeholder involvement are crucial areas in the implementation. This interview study investigated the need for complementary governance, here meaning governance in addition to the governance framework set in the regulation. The interviews involved 23 individuals from the Baltic Sea Region, who are affiliated to the four categories public authority, infrastructure organisation/company, private company and other organisation. The results confirm the importance of an inclusive approach. Further, the results showed a need to ensure that all three social, economic and ecological dimensions of sustainability are considered. Summarising the interview results, four areas for attention in the further CNC implementation process were identified: more and directed information, extended involvement of private sector transport stakeholders, extended involvement of regional and local stakeholders, and involvement of stakeholders located geographically outside the immediate corridor. Complementary governance can be a tool to address these areas, as governance structures and processes can involve stakeholders and steer towards desired outcomes. The interviewees own ideas for complementary governance are presented in this paper. The CNC implementation is currently an on-going process and these results will be further utilised in the process, as a basis for stakeholder discussions of changes in practice.
274

Importance of Fucus vesiculosus (bladderwrack) for coastal fish communities in the Baltic Sea

Mattsson, Emma January 2019 (has links)
Within temperate coastal seascapes, macroalgae provide habitats for different organisms such as invertebrates and fish. In analogy to seagrass meadows, macroalgae beds are known for their importance as fish nurseries. However, within the Baltic Sea the importance of the canopy forming macroalgae Fucus vesiculosus for coastal fish communities, especially the juveniles, is unclear. In order to address this knowledge gap, fish communities in areas with and without F. vesiculosus were investigated around Askö, an island in the archipelago of the Baltic Sea. Sites were subjected to different exposures (sheltered, exposed or very exposed) and three different methods were used for sampling (underwater visual census (UVCs), beach seine netting and remote underwater videos (RUVs)). Overall, fish community composition differed significantly among locations and fish abundance and fish biomass were significantly higher in sites with F. vesiculosus than sites without. There was no significant relationship between algae cover or habitat complexity and fish abundance/biomass in sites with F. vesiculosus. Fish behaviour differed between sites with and without F. vesiculosus, with fish feeding more in sites with F. vesiculosus and traveling more in sites without F. vesiculosus. Only one location, Knabberskär, had significantly higher species richness in F. vesiculosus than in sites without F. vesiculosus. There were no differences in juvenile abundance among sites with or without F. vesiculosus and abundance of adult fish was higher than juvenile fish, regardless of location, site or species. Mean invertebrate abundance was a twice as high in the sheltered location Husbåtsviken than in Knabberskär. Higher fish abundance, fish biomass and species richness in sites with F. vesiculosus compared to sites without, suggest that macroalgae may play an important role in the Baltic Sea, however it might not be as important for juvenile fishes as predicted. The three different sampling methods provided similar results for fish abundance, but not for fish biomass. Continued studies where the relationship between fish communities and aspects of F. vesiculosus structure (such as canopy height) as well as linkage with other habitats is recommended for further understanding and better protection of F. vesiculosus habitats.
275

ASSESSMENT OF MACROALGAE HARVESTING FROM THE BALTIC SEA FROM AN ENERGY BALANCE PERSPECTIVE

Tatarchenko, Olena January 2011 (has links)
Energy balance of large-scale and small-scale scenarios of macroalgae harvesting for biogas production was assessed from the energy balance perspective. Evaluation was based on primary energy Input Output (IO) ratio where all primary energy inputs into the stages of the process life-cycle were summarized and divided by the final energy output from the system. Estimations were made for three cases of possible methane yield from macroalgae as well as for different scenarios of macroalgae co-digestion with other feedstock. Anaerobic digestion of macroalgae as a single substrate both on a small- and large-scale is energy efficient only in case when their methane potential is at the average or high level with the IO ratio of 0.47 and 0.32 correspondently. In general co-digestion with other substrates is more preferable with respect to process condition and energy balance. Large-scale scenario is more stable and efficient than small-scale with the lowest IO ratio for co-digestion with crops. This is explained by the fact that biogas plant operation is among the most energy demanding stages which on the small-scale requires about 65 % of the input energy when this number for large-scale plant does not exceed 28 %. Energy inputs into digestate handling, feedstock pre-treatment and biogas upgrading, that are next most energy consuming stages, is greatly affected by the assumptions made about amount of substrate, produced biogas and transportation distance. When considering the maximal distance between macroalgae harvesting point and biogas production site and to which at which the energy balance remains positive then digestate handling becomes the most energy demanding process stage.
276

Parallelization of the HIROMB ocean model

Wilhelmsson, Tomas January 2002 (has links)
<p>NR 20140805</p>
277

Optimizing resources – studying ways to recycling phosphorus from onsite wastewater treatment plants.

Sammeli, Maria January 2015 (has links)
Eutrophication of the Baltic Sea has been an issue for decades and the pollution constantly continues with oxygen deficient bottoms and a damaged marine life as a result. One of the main causes of eutrophication are elevated levels of the nutrient phosphorus. Phosphorus leaks to the sea from various human activities such as agriculture, animal farming and sewage. In Sweden, the onsite wastewater treatment systems are a big problem since they load the Baltic Sea with nearly as much phosphorus as all Swedish municipal wastewater treatment plants. The need for a reduced impact on the Baltic Sea is major and the individual wastewater treatment systems must therefore be looked over. While phosphorus is a contributing factor to eutrophication, it is one of the most important nutrients for all life. Phosphorus builds up our DNA, helps transport of various substances in and out of our cells and provides energy to the cell's processes. We would simply not be able to survive without phosphorus. We ingest phosphorus through the food we eat, which in turn is dependent on fertilizers containing phosphorus. Phosphorus is mined from phosphate ore and the majority of it is used to produce fertilizers. Unfortunately, phosphate ore is not a finite resource and in the last few years it has been realized that the economically extractable phosphorus is a dwindling resource. To be able to produce food for the world's growing population, we need to find ways to recycle phosphorus. In individual drainage systems there is a large potential to catch up phosphorus and then reuse it on agricultural land. This thesis deals with the problems of onsite wastewater treatment systems and suggests measures to improve their status. Ways to recycle phosphorus in combination with having a well-functioning drainage is being investigated and difficulties about the regulations are being discussed. To recover phosphorus and at the same time reduce the burden on the environment should be seen as an incredibly important action, since our sea’s health is acute but lack of the nutrient could have devastating consequences.
278

Dynamics of internal nutrient sources in the Baltic Sea - A comparative modelling study of the Gulf of Finland.

Dessirier, Benoît, Soltani, Safeyeh January 2011 (has links)
For decades the Baltic Sea has been subject to eutrophication due to heavy anthropogenic nutrient loads on the aquatic ecosystem. Quantitative projections of its effects require an understanding of its driving mechanisms, i.e., the hydrodynamics that are responsible for the physical transport and mixing and the biogeochemical nutrients pathways within the algal ecosystem and between the particulate and dissolved phases in the water and in the sediments. A simple basin-scale hydrodynamic framework is set for the Gulf of Finland to test different descriptions of the biogeochemical transformations and determine the most robust modelling strategy. A recently developed criterion to determine the occurrence of anoxic events, based on the amount of fresh carbon detritus in the sediments is implemented in comparison with the classical criterion based on the oxygen concentration in the bottom water. Time-averaging of the hydrodynamics over larger than daily intervals is proved to hinder the capture of rapid mixing events jeopardizing irremediably the water quality simulation. The new carbon based criterion for anoxia shows a better dynamic response and is less sensitive to the model’s internal parameters. An internal source in the sediments correlated to the amount of fresh detritus, to represent the release of iron-bound phosphorus is confirmed as a versatile modelling assumption.
279

Carbon-based nutrient cycling in the Baltic Sea - Analysis of twelve basins using three-dimensional flow dynamics.

Vigouroux, Guillaume January 2014 (has links)
Eutrophication is a major problem in the Baltic Sea and is the result mainly of the increase of the anthropogenic nutrient loading. Thus, the links among water quality, sediments, and eutrophication have to be understood in order to predict the consequences of our actions and of the climate change on the Baltic Sea. Therefore, water quality models that take into account the hydrodynamics have to be developed to help policy makers. In that perspective, the Kiirikki model, an ecosystem and sediment model, coupled to a box approach has been used to describe the water quality of the Baltic Sea. The latter has been divided into twelve sub-basins according to the topography, each of them separated into two vertical layers. The Kiirikki model has been implemented on each sub-basin and the hydrodynamics are used to link sub-basins between them. After calibration, it can be seen that the model results are consistent with the monitoring data for the southern part, even if the dissolved inorganic nitrogen levels are too high during the winter and some phase shifts are observed. For the northern part, the primary production is well modelled but there is an offset concerning the dissolved inorganic nutrient. Thus, it can be concluded that the implementation of the Kiirikki model is a realistic tool to describe the water quality and eutrophication of the Baltic Sea. However, the differences indicate that the Baltic Sea model cannot be use for policy making yet and more work is needed to improve the model such as a global sensitivity analysis as well as the use of site specific parameters.
280

Exploring Constraints to Russia’s Foreign Policy in the Baltics and the South Caucasus

Sangkogian, Markar January 2021 (has links)
The thesis is an explorative study of the notion of constraints to Russia’s foreign policy. The explorative attempt investigates Moscow’s external behaviour vis a vis the states of the Baltics and the South Caucasus from 2013 to 2020. The analysis argues that the notion of constraints, under the theoretical framework of neoclassical realism, can offer a certain degree of explanatory power in terms of foreign policy variance. The operationalization of the notion, based on Foreign Policy Analysis Theory, proposes specific factors for inspection. Initially, a thematic analysis of Russia’s Foreign Policy Documents of 2013 and 2016, illustrates that the notion of constraints and regionalism is lacking from the perception of the actor. The two documents understand the external world more in terms of threat/risk instead of constraints. Consequently, an examination of the constraints on the level of the international system, and the regional actors demonstrates that the notion holds analytical value under certain circumstances, however, it overlaps with existing frameworks such as that of Tsygankov’s constructivist version, and Structural Realism. The explorative research brings forward fields where the literature on Russia’s foreign policy can be enriched. One of the suggestions is associated with inspecting the notion of fear conditioning in the policy documents of the country.

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