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Abstract  

Thermo-oxidative and thermo-mechanical stabilities of radiation-cured acrylates and epoxides were examined by TG, DMA and DSC.The polymeric trifunctional acrylates PETIA, TMPTA and THEIC displayed the highest temperatures of onset of degradation. The high crosslinking density of the films resulted in an almost temperature-independent complex E-modulus, as measured by DMA. With increasing degree of ethoxylation or propoxylation of the monomers, decreases in thermal stability and strength were found. For difunctional polymeric acrylates and epoxides, the glass transition temperature was measured.The average degree of curing of UV-cured epoxy films can be determined from the temperature of the maximum in the loss modulus (E max.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
B. Markert
,
O. Wappelhorst
,
V. Weckert
,
U. Herpin
,
U. Siewers
,
K. Friese
, and
G. Breulmann

Abstract  

Biomonitoring is a method of observing the impact of external factors on ecosystems and their development over a long period, or of ascertaining differences between one location and another. A monitor suitable for the subject of the investigation must be chosen, and the comparability of the element concentrations thus determined (both within the investigation and with other studies) must be ensured by adhering to precise sampling guidelines. In addition to the small amount of equipment required, the advantages of biomonitoring lie in the ecosystem approach that permits conclusions going beyond the biomonitor itself. Attention has to be given to the factors that may affect element concentrations and which can lead to incorrect statements if ignored.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
M. Douglas
,
J. Friese
,
L. Greenwood
,
O. Farmer
,
M. Thomas
,
T. Maiti
,
E. Finn
,
S. Garofoli
,
P. Gassman
,
M. Huff
,
S. Schulte
,
S. Smith
,
K. Thomas
, and
P. Bachelor

Abstract  

Quantitative measurement of fission and activation products resulting from neutron irradiation of fissile materials is of interest for applications in environmental monitoring, nuclear waste management, and national security. Based on established separation processes involving co-precipitation, solvent extraction, and ion-exchange and extraction chromatography, we have optimized a proposed sequence of separation steps to allow for the timely quantification of analytes of interest. We have recently evaluated this scheme using an irradiated sample to examine the adequacy of separations for measurement of desired analytes by gamma spectrometry. Here we present the radiochemical separations utilized and the yields and purity obtained.

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