Makale

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Browsing Makale by Publisher "Elsevier B.V."

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    A review of the TAEA proficiency test on natural and anthropogenic radionuclides activities in black tea
    (Elsevier B.V., 2018-04) Yeltepe, Emin; Şahin, Namık Kemal; Aslan, Nazife; Hult, Mikael; Özçayan, Gülten; Wershofen, Herbert; Yücel, Ülkü; TAEK-SANAEM
    A proficiency test amongst 15 Turkish laboratories with participation of 5 non-Turkish laboratories was organized to determine the 137Cs, 40K and 90Sr massic activities in black tea powder samples. The bulk material, consisting of tea produced in 2014, was mixed with contaminated tea that was withdrawn from the market after the Chernobyl accident. Nineteen laboratories reported 41 results. The evaluation of the results was based on the accuracy and precision criteria adopted by the IAEA Proficiency Testing Group and resulted in 49% acceptable results, 19% acceptable with warning and 32% were found to be not acceptable.
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    Identification of irradiated sage tea (Salvia officinalis L.) by ESR spectroscopy
    (Elsevier B.V., 2010-04) Tepe Çam, Semra; Engin, Birol; TAEK-SANAEM
    The use of electron spin resonance (ESR) spectroscopy to accurately distinguish irradiated from unirradiated sage tea was examined. Before irradiation, sage tea samples exhibit one asymmetric singlet ESR signal centered at g=2.0037. Beside this central signal, two weak satellite signals situated about 3 mT left and right to it in radiation-induced spectra. Irradiation with increasing doses caused a significant increase in radiation-induced ESR signal intensity at g=2.0265 (the left satellite signal) and this increase was found to be explained by a polynomial varying function. The stability of that radiation-induced ESR signal at room temperature was studied over a storage period of 9 months. Also, the kinetic of signal at g = 2.0265 was studied in detail over a temperature range of 313-353 K by annealing samples at different temperature for various times.
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    Surface modification of pu membranes by graft copolymerization with acrylamide and itaconic acid monomers
    (Elsevier B.V., 2001-10) Babayiğit, Doğan; Pulat, Mehlika; TAEK-RSGD
    To improve water wettability of polyurethane (PU), graft copolymerization of acrylamide (AAm) and itaconic acid (IA) was performed using benzoyl peroxide (BO) initiator. The grafting reaction was carried out by placing the membranes in aqueous solutions of AAm and IA at constant temperatures. Variations of graft yield with time, temperature, initiator and monomer concentrations were investigated. The optimum temperature, polymerization time, initiator and monomer concentrations for AAm were found to be 80°C, 2 h, 4.0x10(-2) M and 1.5 M and for IA, 80°C, 1 h, 4.0x10(-2) M and 1.5 M, respectively. The membranes were characterized by FTIR spectroscopy and scanning electron microscopy (SEM) analysis and the effect of grafting on equilibrium water content (EWC) of PU membranes was obtained by swelling measurements.