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  • Author or Editor: Ö. Şimşek x
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Abstract  

Composite of polyacrylamide-bentonite (PAA-B) was prepared by direct polymerization in a suspension of bentonite (B), the composite was then modified by phytic acid (PAA-B-Phy). The parameters related to adsorption of UO2 2+ in absence and presence of 0.01M CaCl2 and of natural radionuclides (Tl+, Pb2+, Ra2+ and Ac3+ in a leaching solution) onto PAA-B and PAA-B-Phy, and thermodynamics of the adsorption were investigated. Adsorption isotherms were of L and H types for the adsorption of UO2 2+ onto PAA-B and PAA-B-Phy, whilst for Tl+, Pb2+, Ra2+ and Ac3+ they were of C type for both adsorbents. Langmuir equilibrium constants for the adsorption of all studied ions onto PAA-B-Phy were significantly higher than those found for PAA-B. The thermodynamic parameters indicated that adsorption reactions are spontaneous in terms of adsorption free enthalpy. The composite of PAA-B and its modification by Phy have been used for the first time in this study. It is concluded that the composites can be practically used for adsorption and applied as adsorbent of radionuclides.

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Abstract  

The total attenuation cross sections in elements Ti, Fe, Ni and Zn for K and K group of liens of element 22Z92 by using tranmission method. K X-rays of seconder excitor were counted by a Ge(Li) detector with resolution 190 eV at 5.9 keV. The experimentally mesured attentuation cross sections have ben found in a good agreement with the theoretical values of Stom, Israel and Hubbell, Seltzer.

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Abstract  

The L shell X-ray intensity ratios ILα/ILβ, ILα/IL1 and ILα/ILγ for Ta, W, Re, Au, Hg, Tl, Pb, Bi, Th and U have been measured at excitation energies of 59.5 and 122 keV with a Si(Li) detector. Measurements have been performed using Am-241 and Co-57 radioisotope sources. A comparison is made of the experimental results with calculated values obtained using theoretical X-ray emission rates, subshell ionization cross-sections, subshell fluorescence yields and Coster-Kronig transition probabilities. A fairly good agreement is observed between experimental and theoretical values.

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Abstract  

A simple and direct method has been used to obtain fairly accurate total atomic attenuation, total atomic photoelectric and total scattering cross sections by measuring the transmission factor and K X-ray fluorescence spectrum induced by 60 keV -rays for Gd, Tb, Dy and Er by employing a Si(Li) detector system in a 2 geometry set-up. All the parameters are compared with their corresponding theoretical values and a good agreement between them is obtained.

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Abstract  

A new method has been developed to determine K shell fluorescence cross section and K shell fluorescence yields. This method is based on simultaneous measurement of fluorescence radiation and scattered radiation, thus avoiding problems with measuring the source strength and source-to-detector solid angle. The K shell fluorescence cross section and K shell fluorescence yield for 21 elements in the atomic range 22£Z£64 have been measured by using a Si(Li) detector. The obtained results are compared with the other experimental, theoretical and fit values.

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Utilisation of antimicrobial agents at pre- or post-smoking processes was considered for the microbial quality of hot-smoked trout fillets prepared at plant scale. Potassium sorbate (PS) and sodium lactate (SL) were used separately or in combinations at 3% (w/v) in brine for pre-smoking or with spraying at post-smoking. Pre-smoking usage could reduce the total aerobic mesophilic bacteria (TAMB) values better than the post-smoking usage during storage. However, post-smoking application was more effective at preventing the moulds and yeasts (MY) growth. PS in brine at pre-smoking was most efficient, which could keep trout fillets for even four weeks at 6±1°C storage within the range of consumable limits. Additionally, PS usage reduced the contaminated bacterial diversity and especially eliminated the outgrowth of Serratia liquefaciens. As a conclusion, pre-smoking application repressed the contaminated microbial growth during the storage of smoked trout fillets, which may eliminate the microbial risks.

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