Sökning: "cores"

Visar resultat 16 - 20 av 414 avhandlingar innehållade ordet cores.

1. 16. Influence of solar activity and environment on 10Be in recent natural archives

   Författare :Ann-Marie Berggren; Ala Aldahan; Göran Possnert; Anne Hormes; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cosmogenic isotopes; beryllium; ice cores; varved lake sediments; accelerator mass spectrometry; co-precipitation; Quaternary geology; Kvartärgeologi;

   Sammanfattning : Understanding the link between the Sun and climate is vital in the current incidence of global climate change, and 10Be in natural archives constitutes an excellent tracer for this purpose. As cosmic rays enter the atmosphere, cosmogenic isotopes like 10Be and 14C are formed. LÄS MER

3. 17. Late Quaternary climate and environmental change in the summer rainfall region of South Africa : A study using trees and wetland peat cores as natural archives

   Författare :Elin Norström; Karin Holmgren; Michael Meadows; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; paleoclimate; Late Quaternary; pollen; stable isotopes; diatoms; phytoliths; dendroclimatology; South Africa; Physical geography; Naturgeografi; Physical Geography; naturgeografi;

   Sammanfattning : This thesis contributes with information on past climate and environmental changes in South Africa’s summer rainfall region. The study is based on multi-proxy analyses on wetland peat cores and analyses of stable isotope composition (δ13C, δ18O) and wood anatomy in cross sections from subtropical trees (Breonadia salicina). LÄS MER

4. 18. Estimation of Wood Fibre Length Distributions with Data from Increment Cores

   Författare :Ingrid Svensson; Lennart Bondesson; Sara Sjöstedt deLuna; Aila Särkkä; Umeå universitet; []
   Nyckelord :Censoring; EM algorithm; fibre length distribution; increment core; MCEM algorithm; mixture distribution;

   Sammanfattning : .... LÄS MER

5. 19. Burnable poisons in sub-critical cores dedicated to radiotoxic waste transmutation

   Författare :Kamil Tucek; KTH; []
   Nyckelord :;

   Sammanfattning : .... LÄS MER

7. 20. On the Assessment of Internal Erosion of Dam Cores of Glacial Till

   Författare :Hans Rönnqvist; Kaare Höeg; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Soil Mechanics; Geoteknik;

   Sammanfattning : The objective of this study is twofold; on the one hand it investigates the susceptibility to suffusion of glacial till, and, on the other, it presents approaches to evaluate internal erosion susceptibility of dams composed of this type of core soil. Concentrated leak erosion, backward erosion, contact erosion, and suffusion erosion are the mechanisms associated with the initiation of internal erosion. LÄS MER