rss_2.0Nukleonika FeedSciendo RSS Feed for Nukleonikahttps://sciendo.com/journal/NUKAhttps://www.sciendo.comNukleonika 's Coverhttps://sciendo-parsed-data-feed.s3.eu-central-1.amazonaws.com/6230babf7a12a37fd3ccd990/cover-image.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20220627T213753Z&X-Amz-SignedHeaders=host&X-Amz-Expires=604800&X-Amz-Credential=AKIA6AP2G7AKP25APDM2%2F20220627%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Signature=e823b9852cb41ac3bed81a785bffc98a28f6f7e6e690f0c03b5b29ecf8aa40be200300Utilization of an energy-resolving detection system for mammography applications: A preliminary studyhttps://sciendo.com/article/10.2478/nuka-2022-0003<abstract> <title style='display:none'>Abstract</title> <p>Breast cancer remains one of the major causes of mortality among female cancer patients. This fact caused a spark in the medical field, which in turn helped to improve the diagnostic and treatment of breast cancer patients over the years making this field always active with new ideas and innovative methods. In our study, a new method was explored using an energy-resolving detection system made from a NaI (Tl) scintillation detector to detect the gamma photons from an Am-241 radiation source to try and construct an image by scanning the American College of Radiology (ACR) mammography phantom. In addition to the experimental work, a Geant4 Application for Tomographic Emission (GATE) toolkit was used to investigate more complex options to improve the image quality of mammographic systems, which is limited by the experimental setup. From the experimental setup, the researchers were able to construct an image using the 26.3 keV and the 59.5 keV energy photons, to show the largest size tumour (12 mm) in the ACR phantom. With an improved setup in the simulation environment, the majority of the ACR phantom tumours was visible using both energy windows from the 26.3 keV and the 59.5 keV, where the 26.3 keV yielded better quality images showing four tumours compared to three when using 59.5 keV. The simulation results were promising; however, several improvements need to be incorporated into the experimental work so that the system can generate high-resolution mammographic images similar to the ones obtained by the GATE simulation setup.</p> </abstract>ARTICLE2022-06-11T00:00:00.000+00:00Effect of electron beam irradiation on filtering facepiece respirators integrity and filtering efficiencyhttps://sciendo.com/article/10.2478/nuka-2022-0002<abstract> <title style='display:none'>Abstract</title> <p>The outbreak of the COVID-19 pandemic has shown that the demand for medical masks and respirators exceeds the current global stockpile of these items, and there is a dire need to increase the production capacity. Considering that ionizing radiation has been used for sterilization of medical products for many years and electron beam (EB) irradiation enables the treatment of huge quantities of disposable medical products in a short time this method should be tested for the mask’s decontamination. In this work, three different filtering facepiece respirators (FFRs) were irradiated with electron beams of 12 kGy and 25 kGy. The results confirmed that the decrease in filtration efficiency after irradiation of all respirators results from the elimination of the electric charge from the polypropylene (PP) fibers in the irradiation process. Moreover, the applied doses may affect the thermal stability of PP fabrics, while filtering materials structure and integrity have not changed after irradiation.</p> </abstract>ARTICLE2022-06-11T00:00:00.000+00:00Prompt gamma-ray methods for industrial process evaluation: A simulation studyhttps://sciendo.com/article/10.2478/nuka-2022-0001<abstract> <title style='display:none'>Abstract</title> <p>Radioisotope applications in industrial process inspection and evaluation using gamma-ray emitters provide otherwise unavailable information. Offering alternative gamma-ray sources can support the technology by complementing sources’ availability and radiation safety. This work proposes to replace gamma-ray from radioisotopes with prompt gamma-ray from the interaction of neutrons with stable isotopes injected into the industrial process or with the structural material of the industrial process equipment. Monte Carlo N-Particle Transport Code (MCNP5) was used to simulate the irradiation of two-phase flow pipes by <sup>252</sup>Cf neutron source. Two simulations were run for each pipe, with and without mixing the liquid phase with the stable isotope <sup>157</sup>Gd. The detected gamma-ray spectra were analysed, and images of the two phases inside the pipes were produced. The images were compared to images obtained from simulations of gamma transmission measurement using <sup>60</sup>Co. Furthermore, results for prompt gamma computed tomography (CT) were presented and discussed. The studies’ outcomes indicate the potential of prompt gamma-ray to carry out the sealed sources applications of gamma transmission measurements and imaging.</p> </abstract>ARTICLE2022-02-17T00:00:00.000+00:00The influence of electron and gamma irradiation on the properties of starch:PVA films – the effect of irradiation dosehttps://sciendo.com/article/10.2478/nuka-2021-0001<abstract><title style='display:none'>Abstract</title><p>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 <sup>60</sup>Co 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.</p></abstract>ARTICLE2021-03-06T00:00:00.000+00:00Natural zeolite as a replacement for resin in the cation exchange process of cesium on post-irradiated nuclear fuelhttps://sciendo.com/article/10.2478/nuka-2021-0002<abstract><title style='display:none'>Abstract</title><p>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 NH<sub>4</sub>Cl, and heated at 200°C, the bond stability test of <sup>137</sup>Cs-zeolite, chemical composition analysis, surface area, pore size, analysis of Cs cation exchange capacity (CEC), diffusion coefficient (<italic>D<sub>i</sub></italic>), activation energy (<italic>E<sub>a</sub></italic>), and absorption of three zeolites. To do this, pipette 50 μl of a standard solution of <sup>137</sup>Cs 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 <sup>137</sup>C isotope will exchange ions with NH<sub>4</sub>-zeolite to <sup>137</sup>Cs-zeolite in the solid phase. The content of <sup>137</sup>Cs in <sup>137</sup>Cs-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 <italic>D<sub>i</sub></italic> and <italic>E<sub>a</sub></italic> 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 <sup>137</sup>Cs isotope separation in 150 μl of U<sub>3</sub>Si<sub>2</sub>/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 <sup>137</sup>Cs isotope in nuclear fuel post-irradiated.</p></abstract>ARTICLE2021-03-06T00:00:00.000+00:00A virtual laboratory for radiotracer and sealed-source applications in industryhttps://sciendo.com/article/10.2478/nuka-2021-0003<abstract><title style='display:none'>Abstract</title><p>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.</p></abstract>ARTICLE2021-03-06T00:00:00.000+00:00Chemical characterization of PM10 in two small towns located in South Polandhttps://sciendo.com/article/10.2478/nuka-2021-0004<abstract><title style='display:none'>Abstract</title><p>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<sup>−3</sup> 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.</p></abstract>ARTICLE2021-03-06T00:00:00.000+00:00Radiological characterization of the phosphate deposit in Al-Jalamid phosphate mining area, Saudi Arabiahttps://sciendo.com/article/10.2478/nuka-2021-0005<abstract><title style='display:none'>Abstract</title><p>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.</p></abstract>ARTICLE2021-03-06T00:00:00.000+00:00Plasma technology to remove NO from off-gaseshttps://sciendo.com/article/10.2478/nuka-2021-0033<abstract> <title style='display:none'>Abstract</title> <p>Operation of marine diesel engines causes significant emission of sulphur and nitrogen oxides. It was noticed worldwide and the regulations concerning harmful emissions were introduced. There were several solutions elaborated; however, emission control for both SO<sub>x</sub> and NO<sub>x</sub> requires two distinctive processes realized in separated devices, which is problematic due to limited space on ship board and high overall costs. Therefore, the electron beam flue gas treatment (EBFGT) process was adopted to ensure the abatement of the problem of marine diesel off-gases. This novel solution combines two main processes: first the flue gas is irradiated with electron beam where NO and SO<sub>2</sub> are oxidized; the second stage is wet scrubbing to remove both pollutants with high efficiency. Laboratory tests showed that this process could be effectively applied to remove SO<sub>2</sub> and NO<sub>x</sub> from diesel engine off-gases. Different compositions of absorbing solution with three different oxidants (NaClO, NaClO<sub>2</sub> and NaClO<sub>3</sub>) were tested. The highest NO<sub>x</sub> removal efficiency (&gt;96%) was obtained when seawater-NaClO<sub>2</sub>-NaOH was used as scrubber solution at 10.9 kGy dose. The process was further tested in real maritime conditions at Riga shipyard, Latvia. More than 45% NO<sub>x</sub> was removed at a 5.5 kGy dose, corresponding to 4800 Nm<sup>3</sup>/h off-gases arising from ship emission. The operation of the plant was the first case of examination of the hybrid electron beam technology in real conditions. Taking into account the experiment conditions, good agreement was obtained with laboratory tests. The results obtained in Riga shipyard provided valuable information for the application of this technology for control of large cargo ship emission.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Decomposition of diclofenac in sewage from municipal wastewater treatment plant using ionizing radiationhttps://sciendo.com/article/10.2478/nuka-2021-0029<abstract> <title style='display:none'>Abstract</title> <p>The decomposition of diclofenac (DCF) in sewage sludge from municipal wastewater treatment plant was investigated. It was found that adsorption of DCF on sludge is about 40%. Compared to previous studies, where the degradation yield in aqueous solution was 100%, in those experiments at the dose up to 5 kGy, only 50% of initial DCF concentration of 50 mg L<sup>−1</sup> was decomposed in sediment and in solution over the sediment. The experiments were carried out using both gamma radiation and electron beam. It has been observed that DCF in the aqueous phase, above the sediment, was decomposed with the same efficiency using both gamma radiation and electron beam. Whereas for DCF in the sediment, a higher degradation efficiency was found when gamma radiation was applied. This is most likely due to the limited penetration depth of the electron beam into the sludge layer. It was shown that the applied peroxide addition (in a stoichiometric amount needed for complete mineralization of 50 mg L<sup>−1</sup> DCF) did not cause increase in yield of DCF decomposition.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Radiolytic synthesis of gold nanoparticles in HEMA-based hydrogels: Potentialities for imaging nanocompositeshttps://sciendo.com/article/10.2478/nuka-2021-0025<abstract> <title style='display:none'>Abstract</title> <p>This article reports on the radiolytic synthesis of nanocomposites containing gold nanoparticles (AuNPs) within two types of hydrogels based on 2-hydroxyethyl methacrylate (HEMA): (i) plain networks with various contents in ethylene glycol dimethacrylate (EGDMA), as a cross-linker and (ii) stimuli-responsive (SR) networks prepared from these monomers copolymerized with [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT) to confer pH-switchable swelling. Hydrogels were prepared by photopolymerization with well-defined composition and a high degree of monomer conversion using two experimental procedures, as xerogels or in aqueous solution. Besides MADQUAT, acrylic acid (AA) or <italic>N</italic>-isopropylacrylamide have been tested as copolymers, yielding pHor temperature-sensitive hydrogels, respectively. Isothermal swelling in water was affected by monomer composition. Electron beam (EB) irradiation at doses up to 100 kGy of poly(HEMA) xerogels and water-swollen networks prepared with 0.5 wt% of EGDMA had a moderate impact on swelling characteristics and thermomechanical properties of the plain materials, whereas small amounts of extractables were formed. Poly(HEMA)-based nanocomposites containing AuNPs were successfully obtained by EB irradiation of samples swollen by aqueous solutions of Au(III). The effects of dose and cross-linking density on the formation of AuNPs were monitored by UV-visible spectroscopy. Irradiation at well-defined temperatures of the Au(III)-loaded SR hydrogels induced the formation of nanoparticles with size-dependent features, whereas the efficiency of Au(III) reduction at 10 kGy was not significantly affected by the network structure. EB-induced reduction of Au(III) in poly(HEMA) hydrogels using a lead mask to generate well-defined patterns yielded coloured and long-lasting images in the zones where the nanocomposite was formed.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00The International Conference on Development and Applications of Nuclear Technologies, NUTECH-2020, Warsaw, Poland, 4–7 October 2020https://sciendo.com/article/10.2478/nuka-2021-0016ARTICLE2021-11-25T00:00:00.000+00:00Combination of methods of thermal and radiation treatment of sediments associated with PCBs – the Delor typehttps://sciendo.com/article/10.2478/nuka-2021-0030<abstract> <title style='display:none'>Abstract</title> <p>An efficient method of burning polychlorinated biphenyls (PCBs) is often used to remove the environmental burden of PCBs. However, combustion produces toxic dioxins and furans (PCDD/F), so residents are increasingly rejecting this method. The heat treatment (HT) method does not burn PCBs but evaporates it from sediments. Even in this process, PCDD/Fs are formed to a lesser extent, which are destroyed by radiation processing (RP) following the HT. At the same time, the RP method degrades PCB congeners down to biphenyls, which decompose easily in the environment. A block assembly of a complex synergistic combination of equipment for methods of thermal (HT) and radiation (RP) destruction of PCBs in sediments is proposed. The efficacy of this complex was preliminarily determined at a level of 70-fold reduction in PCB concentration in sediments. To achieve a higher reduction factor in the concentration of PCBs, possible procedures for optimizing the settings of individual devices of this complex are presented.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Sub-cellular elemental imaging of human muscle tissues affected by neuromuscular diseaseshttps://sciendo.com/article/10.2478/nuka-2021-0024<abstract> <title style='display:none'>Abstract</title> <p>Various types of neuromuscular diseases differ in symptoms, pathology, and clinical picture but one of their common elements is muscle weakness, which could lead to human motor activities impairment and in many cases to shortening of life span and even death due to respiratory failure. That is why it is very important to better understand the underlying causes of these diseases to be able to implement new methods of treatment more effectively. This paper presents the results of the elemental analysis of human muscular tissues affected by dystrophy and myopathy. For this purpose, the particle-induced X-ray emission method was used, which is perfectly suited for measuring light elements. The samples were analysed for differences in the elemental composition of Na, Mg, P, S, Cl, K, Fe, Zn, and Br. The results were presented in the form of elemental concentration maps and a thorough statistical analysis of the obtained data using the advanced statistical methods.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Numerical modelling of modular high-temperature gas-cooled reactors with thorium fuelhttps://sciendo.com/article/10.2478/nuka-2021-0020<abstract> <title style='display:none'>Abstract</title> <p>The volumetric homogenization method for the simplified modelling of modular high-temperature gas-cooled reactor core with thorium-uranium fuel is presented in the paper. The method significantly reduces the complexity of the 3D numerical model. Hence, the computation time associated with the time-consuming Monte Carlo modelling of neutron transport is considerably reduced. Example results comprise the time evolutions of the effective neutron multiplication factor and fissionable isotopes (<sup>233</sup>U, <sup>235</sup>U, <sup>239</sup>Pu, <sup>241</sup>Pu) for a few configurations of the initial reactor core.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00GC investigation of post-irradiation oxidation phenomena on polypropylenehttps://sciendo.com/article/10.2478/nuka-2021-0027<abstract> <title style='display:none'>Abstract</title> <p>The paper summarizes the results of research on gas products of polypropylene (PP) radiolysis. Particular attention was paid to the phenomena of post-radiation degradation of PP. The protective effect of selected aromatic compounds was investigated. The research was carried out both from the point of view of obtaining radiation-resistant PP varieties and the possibility of accelerating biodegradation phenomena, e.g., PP/cellulose composition. The phenomena of post-radiation chain oxidation of PP were investigated by gas chromatography (GC). The GC in the system used (packed column, thermal conductivity detector, argon – carrier gas) enables the determination of H<sub>2</sub>, O<sub>2</sub>, CO, and CH<sub>4</sub> in one measurement. The samples were irradiated with electron beams (EBs) accelerated in accelerators: Elektronika 10/10 with a power of 10 kW and energy of 10 MeV and LAE 13/9 with a power of 9 kW and energy up to 13 MeV. In the tests, PP without stabilizing additives (obtained directly from the production line) and non-stabilized styrene were used. Radiolytic efficiency of hydrogen evolution allowed us to estimate the number of originally formed free radicals. The maintenance of the secondary oxidation processes was the loss of oxygen and the formation of oxidation products (CO, CH<sub>4</sub>). Attention is paid to the protective effect of aromatic compounds (polystyrene (PS), polyethylene terephthalate (PET), anthracene, fluoranthene, acenaphthene, pyrene, naphthalene) both at the stage of hydrogen atom separation and the secondary oxidation process. The examples of post-radiation oxidation of PP irradiated in cryogenic conditions (–196°C) are presented. All used aromatic compounds showed a protective effect in PP radiolysis. We suppose that this phenomenon is responsible for the charge transfer along the polymer chain from the ionization spurs to the aromatic compound. The protective ranges of PS in PP radiolysis were estimated for the variously prepared PP/PS type compositions from 6 mers to 28 mers.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Radiation synthesis of poly(acrylic acid) nanogels for drug delivery applications – post-synthesis product colloidal stabilityhttps://sciendo.com/article/10.2478/nuka-2021-0026<abstract> <title style='display:none'>Abstract</title> <p>Synthesis of polymer nanogels (NGs) for biomedical applications is considered to be a very promising application in radiation engineering. Under high-dose pulse irradiation of dilute aqueous polymer solution, reactive species generated by water radiolysis can create multiple radicals on each macromolecule and consequently induce intramolecular cross-linking of polymer chains, resulting in NG formation. The obtained products are free from harmful monomers, initiators, and cross-linking agents, which makes them potentially applicable for drug delivery applications. One of the biggest challenges in handling and use of nanoparticles, however, is the colloidal stability, when aqueous suspensions are stored for prolonged periods. Therefore, development of the best protocols for the particular nanocarrier storage is key. To address this need, we have performed the prospective study in which we systematically assessed the influence of various processing and storage scenarios feasible in our lab, on the colloidal stability of the radiation-synthesized poly(acrylic acid) (PAA) NG particles in suspension. This allowed us to choose the optimal way of handling the product after its synthesis. We confirmed that none of the strategies we used and tested are substantially detrimental to our product. Filtration with 0.2-μm filters was proven sufficient for sample purification and prolonged storage in aqueous suspension did not exert a negative effect on the colloidal stability of particles suspension. We have also demonstrated that lyoprotectant-free lyophilization was suitable for our polymer nanoparticles. This is an important fact for further application of particles as nanocarriers for biologically active compounds such as targeting ligands or therapeutic moieties.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Studies on uranium recovery from a U-bearing Radoniów Dumphttps://sciendo.com/article/10.2478/nuka-2021-0017<abstract> <title style='display:none'>Abstract</title> <p>This work reports the possibility of uranium recovery from a post-mining uranium ore dump in Poland by a bioleaching method. The studies were conducted on the dump leaching model with the mass of 570 kg of uranium bearing mineral material from Radoniów pile and in the periodic bioreactor with a work volume of 80 dm<sup>3</sup> and with mechanical mixing and aeration of the charge. The uranium concentration in the examined material was about 800 ppm. In this process, the consortium of microorganisms isolated from former mines was used. It was composed of the following microorganisms: <italic>Bacillius</italic>, <italic>Pseudomonas</italic>, <italic>Sphingomonas</italic>, <italic>Thiobacillus</italic>, <italic>Halothiobacillus</italic>, <italic>Thiomonas</italic>, and <italic>Geothrix.</italic> The efficiency of the uranium bioleaching process was 98% in the reactor, and a yield of 70% was obtained in the dump leaching model. The post-leaching solution contained significant amounts of uranium ions that were separated in two stages: (1) by ion chromatography and then (2) by a two-step precipitation method. The resulting solution was a source of ammonium diuranate, the precursor of yellowcake (uranium oxides).</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Effect of gamma irradiation on microbiological and nutritional properties of the freeze-dried berrieshttps://sciendo.com/article/10.2478/nuka-2021-0032<abstract> <title style='display:none'>Abstract</title> <p>Lyophilization or freeze-drying is the technique of removing ice or other frozen solvents from a material through sublimation and the removal of bound water molecules through the process of desorption. Drying occurs in an absolute vacuum at temperatures from −40°C to −50°C. This technique is often used for the conservation of fruits, especially berries. During this process, the water changes from frozen to gaseous, with no thawing. Due to low temperatures and the high vacuum, most microorganisms are rendered inactive during the lyophilization process. However, if there is a necessity to destroy all microorganisms from treated food, subsequent irradiation with gamma rays is an appropriate method. This paper investigated the influence of different doses of gamma radiation on lyophilized berries’ microbiological characteristics. It was shown that the radiation dose of 7 kGy is sufficient to eliminate the total number of microorganisms (excluding molds) to the extent that the number falls below the permitted limit according t o the law on the microbiological safety of foodstuffs of the Republic of Serbia, and 5 kGy is enough for molds to be rendered inactive. It was also concluded that gamma irradiation does not affect the nutritional value of lyophilized berries.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00Sorption of selected radionuclides from liquid radioactive waste by sorbents of biological origin: The alkaline earth alginateshttps://sciendo.com/article/10.2478/nuka-2021-0023<abstract> <title style='display:none'>Abstract</title> <p>The sorption of <sup>241</sup>Am<sup>3+</sup>, <sup>85</sup>Sr<sup>2+</sup> and <sup>137</sup>Cs<sup>+</sup> by calcium, strontium and barium alginates has been studied under different operation conditions. The most prominent adsorption was found in the pH range of 5–6 for all systems, even if the observed dependence on the acidity of the solution was small. The most favourable time for the adsorption process was found to be about 2 h for calcium alginate and 4 h for the other two sorbents.</p> </abstract>ARTICLE2021-11-25T00:00:00.000+00:00en-us-1