Sökning: "plasma instrumentation"

Visar resultat 21 - 25 av 29 avhandlingar innehållade orden plasma instrumentation.

1. 21. The Neutral Particle Detector on the Mars and Venus Express missions

   Författare :Alexander Grigoriev; Stas Barabash; Brian J. Anderson; Umeå universitet; []
   Nyckelord :Space and plasma physics; ENA imaging; exosphere; magnetosphere; Mars; Venus; solar wind interaction; Rymd- och plasmafysik; rymd- och plasmafysik; Space and Plasma Physics;

   Sammanfattning : The Neutral Particle Detector (NPD) is a new type of instrumentation for energetic neutral atom (ENA) diagnostics. This thesis deals with development of the NPD sensor designed as a part of the plasma and neutral particle packages ASPERA-3 and ASPERA-4 on board Mars Express and Venus Express, the European Space Agency (ESA) satellites to Mars and Venus, respectively. LÄS MER

3. 22. Are gadolinium contrast media really less nephrotoxic than iodine agents in radiographic examinations? A comparison in relation to their ability to attenuate x-rays in a pig model

   Författare :Barbara Elmståhl; Malmö Diagnostisk radiologi; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Angiography; Computed tomography; toxicity; Contrast media; Glomerular filtration; Gadolinium; Iodine; Kidney failure; Nephrotoxicity.; Medicin människa och djur ; radiology; Clinical physics; Medicine human and vertebrates ; tomography; medical instrumentation; Diagnostik; Diagnostics; medicinsk instrumentering; tomografi; radiologi; Klinisk fysiologi;

   Sammanfattning : Purpose: To confront the statement that gadolinium contrast media (Gd-CM) are less nephrotoxic than iodine contrast media (I-CM) when used in x-ray angiographic and computed tomographic (CT) examinations. Methods: I) For CT measurements (mean density in Hounsfield numbers) 20-mL syringes filled with I- and Gd-CM at 0.01, 0.02, 0. LÄS MER

4. 23. Isotope Ratio and Trace Element Measurements Using Inductively Coupled Plasma – Mass Spectrometry : Method Development and Applications in Environmental Forensics

   Författare :Simon Pontér; Anders Widerlund; Hjalmar Laudon; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Isotope ratio measurements; screening analysis; ICP-MS; MC-ICP-MC; multi-tracer studies; fractionation; Environmental Forensics; Tracing; Tillämpad geokemi; Applied Geochemistry;

   Sammanfattning : Environmental Forensics is a scientific methodology developed for identifying sources, the timing of release, and transport pathways for potentially hazardous environmental contaminants. It combines a variety of analytical methods with principles derived from disciplines such as chemistry, geology, geochemistry, hydrogeology, and statistics, with the purpose to provide objective scientific and legal conclusions on the source and/or time of a contaminant release. LÄS MER

5. 24. Development of Neutron Emission Spectroscopy Instrumentation for Deuterium and Deuterium-Tritium Fusion Plasmas at JET

   Författare :Luca Giacomelli; Jan Källne; Thomas Sangster; Uppsala universitet; []
   Nyckelord :Nuclear physics; neutron spectroscopy; MPRu; TOFOR; JET; Radio frequency heating; Count rate; Kärnfysik;

   Sammanfattning : The study of high power fusion plasmas at the JET tokamak has been further enhanced through the development of instrumentation for neutron emission spectroscopy (NES) measurements. This has involved the upgrade of the magnetic proton recoil (MPR) spectrometer used for deuterium-tritium plasmas earlier so that the MPRu can now be also employed for deuterium (D) plasmas. LÄS MER

7. 25. Speciation analysis of butyl- and phenyltin compounds in environmental samples by GC separation and atomic spectrometric detection

   Författare :Dong Nguyen Van; Wolfgang Frech; Anders Cedergren; Erwin Rosenberg; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organotin speciation analysis; species-specific isotope dilution; inductively coupled plasma mass spectrometry; single isotope spike; multi-isotope spike; redistribution; species transformation; preparative liquid chromatography; gas chromatography; line source atomic absorption spectrometry; continuum source atomic absorption spectrometry; Analytical chemistry; Analytisk kemi;

   Sammanfattning : The main goal of the work presented in this thesis is to improve the reliability of existing methods for speciation analysis of organotin compounds Species-specific isotope dilution (SSID) calibration in combination with gas chromatography – inductively coupled plasma mass spectrometry was used to investigate the transformation of phenyltin species during sample preparation. Isotope-enriched phenyltin species were synthesized from corresponding isotope-enriched tin metals. LÄS MER