Solving electromagnetic boundary problems with equivalence methods

A basic problem in electromagnetics involves solving the Maxwell equations in a non-empty space, i.e. in a space with interfaces or boundaries. In this dissertation the wanted electromagnetic fields are searched via equivalence methods: a full electromagnetic problem is transformed to a simpler solvable form, or the solution is an equivalent source, or both. The chosen transformations result to two slightly different transmission line formulations or to Kelvin inversion (inversion in a sphere). The equivalent source is typically an image source. The included cases are 1) a planar multilayer chiral structure, 2) a conducting earth under a current source, 3) a sphere in an isotropic or bi-isotropic space, and 4) three types of anisotropic half-space-planar boundary or half-space problems. The first two cases (three papers) are time-dependent problems and the latter two (four papers) statics or quasi-statics. In each case the solution methodology is presented, the solutions are written, and the implications and limitations are discussed.reviewe

Обзор конъюнктуры рынка в лесной отрасли Финляндии 2015-2016

Luken kirjat, raportit, oppaat ja esitteet. Metsäsektorin suhdannekatsaus 2015-2016, venäjänkielinen tiivistelmä201

Murtovesikurssien opetuksesta, toteutuksesta ja sattumuksista

Nykymuotoisen murtovesiekologian kenttäkurssin historia alkaa vuodesta 2003. Tuolloin silloiseen Turun yliopiston Ympäristöntutkimuskeskukseen (TYYK) kuulunut Saaristomeren tutkimuslaitos otti veto- ja järjestelyvastuun Biologian laitoksen ekologian osaston Akvaattisen ekologian kenttäkurssin murtovesiosiosta.</p

Koronapandemian vaikutuksia merentutkimukseen

Kaikki merellä tehtävät meriseurantojen näytteenotot on keskeytetty</p

Puutuoteteollisuus avainasemassa metsäbiotalouden kehityksessä

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The Baltic Sea Ecosystem Regulation Mechanism

Short communication: Understanding the functioning of the Baltic Sea ecosystem has been one of the most important tasks of the Seili Research Station of the University of Turku, Finland. Understanding requires not only the study of the regulatory mechanisms of the Baltic Sea ecosystem, but also the study of the climatic conditions of the Atlantic, as the climatic conditions of the ocean ultimately determine how the Baltic Sea ecosystem develops.</p

Mesozooplankton trends and distributions in pelagic and littoral habitats of the Archipelago Sea, the northern Baltic Sea, SW Finland

This study investigated the occurrence and diversity of zooplankton communities in the Archipelago Sea, the northern Baltic Sea, SW Finland. Zooplankton was sampled from rocky shores in three regions: the inner archipelago (at Paimionlahti), the middle archipelago (at Seili), and the outer archipelago (at Utö) in autumn 1997. Samples were taken from the surface layer (0–1 m) in the coastal zone, i.e., in the littoral and in the nearby pelagic areas during the day and during the night. Zooplankton taxa were identified for groups of cladocerans (Cladocera), copepods (Copepoda), or rotifers (Rotifera). We investigated whether the archipelago zonation is observable also in the distribution of zooplankton communities, mainly on the basis of species numbers, abundances, the Shannon-Wiener (H’) and the Simpson Diversity (D) Indices, and whether there are differences in species numbers and diversity between the day and the night (through vertical migration) or between the littoral and the pelagic habitats. Comparisons were made with non-parametric ANOVA and generalized linear models (GENMOD). Analyses revealed that the archipelago zones can, to a certain extent, be observed on the basis of the numbers of zooplankton species. Species numbers and diversity generally increased towards the outer archipelago in both the littoral and the pelagic habitats. The increase can be explained mainly by the seawater salinity. Zooplankton diversities between the day and night and between the littoral and the pelagic habitats were different in the inner and outer archipelagos that can be explained by zooplankton horizontal and vertical migrations or drifting. The results are discussed considering the zooplankton community changes that have occurred in the study area since 2000