Sökning: "Ala Aldahan"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Ala Aldahan.

1. 1. Accelerator Mass Spectrometry of 36Cl and 129I : Analytical Aspects and Applications

   Författare :Vasily Alfimov; Göran Possnert; Ala Aldahan; Hans-Arno Synal; Uppsala universitet; []
   Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Environmental technology; Accelerator Mass Spectrometry; iodine-129; chlorine-36; gas-filled magnet; radioactive tracer; Arctic Ocean; Nordic Seas; North Atlantic; thermohaline circulation; Sellafield; La Hague; Miljöteknik; Environmental engineering; Miljöteknik;

   Sammanfattning : Two long-lived halogen radionuclides (36Cl, T1/2 = 301 kyr, and 129I, T1/2 = 15.7 Myr) have been studied by means of Accelerator Mass Spectrometry (AMS) at the Uppsala Tandem Laboratory. The 36Cl measurements in natural samples using a medium-sized tandem accelerator (~1 MeV/amu) have been considered. LÄS MER

3. 2. 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 :NATURAL SCIENCES; NATURVETENSKAP; 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

4. 3. Anthropogenic 129I Traced in Environmental Archives by Accelerator Mass Spectrometry

   Författare :Edvard Englund; Göran Possnert; Ala Aldahan; José María López-Gutiérrez; Uppsala universitet; []
   Nyckelord :Engineering physics; iodine-129; sediment; aerosol; reprocessing; Chernobyl; nuclear weapon; Sellafield; La Hague; accelerator mass spectrometry; AMS; Teknisk fysik;

   Sammanfattning : Since the beginning of the nuclear era, starting during the 1940s, large amount of radioactivity has been released into the environment. This thesis deals with the temporal and spatial distribution of the anthropogenic radioisotope 129I (T1/2= 15.7 Myr) in northern Europe. LÄS MER

5. 4. Iodine Isotopes and their Species in Surface Water from the North Sea to the Northeastern Atlantic Ocean

   Författare :Peng He; Ala Aldahan; Per Roos; Uppsala universitet; []
   Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; iodine isotopes; 129I; 127I; oceans; North Sea; speciation; Atlantic Ocean; English Channel; Celtic Sea; AMS; iodine chemistry; geochemistry; Earth Science with specialization in Environmental Analysis; Geovetenskap med inriktning mot miljöanalys;

   Sammanfattning : Huge amounts of anthropogenic 129I have been and still are released to the environment through liquid and gaseous discharges from the nuclear fuel reprocessing facilities worldwide and in particular the ones in Europe. Most of this 129I signal has been accumulated in the marine environment which plays a major role in the iodine natural pool. LÄS MER

7. 5. Distribution, Sources and Environmental Pathways of Radioactive 129I in Fresh and Saline Water in the Baltic Region

   Författare :Abdulaziz Kekli; Ala Aldahan; Xiaolin Hou; Uppsala universitet; []
   Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Earth sciences; 129I; iodine; environment; precipitation; river; Baltic Sea; radioactivity; Geovetenskap; Earth sciences; Geovetenskap;

   Sammanfattning : This thesis deals with distribution, sources and pathways of radioactive 129I (T1/2=15.6 My) in 54 rivers covering the Baltic region, precipitation (rain and snow) from southern, central and northern Sweden, and saline water from three depth profiles in the Baltic Sea and a surface water transect from the Baltic to the Kattegat. LÄS MER