Volume 66 (2021): Edizione 1 (March 2021)

The paper discusses the effect of ionizing radiation on the functional properties of the biodegradable starch:PVA films. The analysis is related to the possible use of the material for packing the products (particularly, food) that are predicted for radiation decontamination and to the potential modification of the material by radiation treatment. Our previous results have shown that the influence of ionizing radiation on the films’ properties varied for the specific compositions (differing in starch:PVA ratio or the type of substrates) and depended on irradiation conditions. However, these studies considered only the irradiation performed in gamma chamber or in e-beam using a dose of 25 kGy. Therefore, the present study deals with the effect of the irradiations performed using various doses on the selected promising starch:PVA composition. The films characterized by starch:PVA weight ratio of 45:55 was obtained by solution casting and irradiated with fast electrons in air and with ⁶⁰Co gamma rays in nitrogen applying the doses of 5, 10, 20, 25, 30, 50, and 75 kGy. No regular dependence has been noticed between the composition of films (differing in the starch and PVA content) and the intensities of the particular bands in the UV-VIS DRS spectra after irradiation. The results indicated strong interaction of the starch and PVA components in the films and the occurrence of specific reactions in each composition upon irradiation. No special differences were observed between tensile strength and Young’s modulus of the non-irradiated films characterized by the starch:PVA ratio equal to 45:55 and the samples irradiated using doses in the range of 5–75 kGy. Similarly, no differences were observed in both cases between the swelling capability of the non-irradiated and the irradiated films. However, it can be deduced that solubility in water increased when the radiation dose increased. The results show that using the doses till the range 25 kGy does not cause an essential change of all the examined properties of the starch:PVA (45:55) films. Accordingly, starch:PVA (45:55) films might be considered suitable for packing food predicted for radiation decontamination.

Characterization of natural salts from Bayah, Lampung, and Tasikmalaya, Indonesia has been carried out as a substitute for synthetic resins. The characteristics include zeolite activation with NH₄Cl, and heated at 200°C, the bond stability test of ¹³⁷Cs-zeolite, chemical composition analysis, surface area, pore size, analysis of Cs cation exchange capacity (CEC), diffusion coefficient (D_i), activation energy (E_a), and absorption of three zeolites. To do this, pipette 50 μl of a standard solution of ¹³⁷Cs from the National Institute of Standards and Technology (NIST), put in, 2 ml of 0.1 N HCl, and then add 1 g of zeolite and stir each for 1, 2, 3, 4, 5, and 24 h. Based on this stirring time, the ¹³⁷C isotope will exchange ions with NH₄-zeolite to ¹³⁷Cs-zeolite in the solid phase. The content of ¹³⁷Cs in ¹³⁷Cs-zeolites (solid phase) was analysed using a gamma spectrometer. The results of the chemical composition analysis showed that the character of zeolite from Lampung has a Si/Al ratio, with a CEC value of 1.448 mEq/g which is greater than Bayah and Tasikmalaya, while the D_i and E_a values for the three select types were obtained almost the same. Moreover, the stability test of the Cs ion bond with zeolite showed no significant release of Cs ions from the zeolite structure. It can be concluded that the three soloists tested that the zeolite from Lampung has better characters. The results of ¹³⁷Cs isotope separation in 150 μl of U₃Si₂/Al fuel solution post-irradiation using zeolite from Lampung and Dowex resins obtained almost the same recovery around 98–99%, so it can be concluded that zeolite from Lampung can be used as a substitute for synthetic resin in the cation exchange process for the ¹³⁷Cs isotope in nuclear fuel post-irradiated.

Radioactive sealed sources and radiotracer techniques are used to diagnose industrial process units. This work introduces a workspace to simulate four sealed sources and radiotracer applications, namely, gamma scanning of distillation columns, gamma scanning of pipes, gamma transmission tomography, and radiotracer flow rate measurements. The workspace was created in Geant4 Application for Tomographic Emission (GATE) simulation toolkit and was called Industrial Radioisotope Applications Virtual Laboratory. The flexibility of GATE and the fact that it is an open-source software render it advantageous to radioisotope technology practitioners, educators, and students. The comparison of the simulation results with experimental results that are available in the literature showed the effectiveness of the virtual laboratory.

The purpose of this study is to analyse the elements and PM10 concentrations in air samples gathered in the winter of 2017/2018 in two small towns, namely Skala and Wadowice. The chemical elements were identified for each sample using the energy dispersive X-ray method. The spectrometer was equipped, among others, with an Mo-X-ray tube which was the source of the photons and the Si(Li) detector. The following chemical elements: Cl, K, Fe, Ca, Zn, Pb, Br, Ti, Cu, Mn, V, Co, Rb, Ni, Sr, and Cr were identified in the samples. In addition, As and Se were identified in Wadowice. First, the results were compared with each other and then with the results for the nearest city. It was observed that the PM10 concentrations were significantly higher than the UE limit value for PM10, which equals 50 μg·m⁻³ per 24 h. Moreover, the high concentrations of, among others, K, Pb, Cl or Zn, are likely to be linked with fossil fuels combustion and biomass burning. The levels of element concentrations in Wadowice and Skala resemble the levels observed several years earlier in Krakow.

It is a known fact that phosphate rocks have high levels of natural radioactivity due to the presence of large concentrations of radionuclides. This work aims to estimate radiation exposure and dose levels at Al-Jalamid site in northern Saudi Arabia. Al-Jalamid area is one of the largest reserves of phosphate worldwide. Ma’aden, a Saudi Government public company, owns the mine and is responsible for all mining activities. Phosphate and soil samples collected from Al-Jalamid phosphate mining area have been analysed for their uranium and thorium content by an α-spectrometer using radiochemical techniques. The quantity of radon gas was measured both in groundwater and in the atmosphere (indoor and outdoor) at the site using a portable radiation survey instrument. Groundwater samples collected from wells surrounding the mining area were analysed using a liquid scintillation counter in addition to an α-spectrometer. Finally, it is found that phosphate rock concentrate products cannot be utilized economically based on the standards set by the International Atomic Energy Agency (IAEA), since the average activity concentration does not reach the limit set by IAEA and hence are not commercially feasible.