Volume 113, Issue 12

The flux-weighted average cross-sections of the nat Pd(n,xn) 109,101 Pd and nat Pd(n,pxn) 105,106m Rh reactions with the average neutron energies of 20.3–32.3 MeV were measured for the first time by using an activation and off-line γ -ray spectrometric technique. The fast neutrons were generated by using the 9 Be(p,n) reaction with the proton energies of 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron spectra were simulated by using the computer code MCNPX 2.6.0, whereas the experimental neutron fluxes were measured by using the 27 Al(n,α) 24 Na monitor reaction. Thus the experimentally obtained reaction cross-sections are for the spectrum neutron energies, which range from the threshold energy to 33.0 MeV and 42.8 MeV, respectively. The present data within the average neutron energy of 20.3–32.3 MeV and the literature data at lower energy were compared with the theoretically calculated values from the TENDL-2019 library and found to be in good agreement in most of the cases.

Proton-induced reaction cross sections for 64 Zn( p,γ ) 65 Ga, 67 Zn( p,γ ) 68 Ga, 70 Zn( p,n ) 70 Ga, and nat Zn( p,x ) 67 Ga were measured in the 2.0–4.0 MeV energy range at a 3 MV Tandem Accelerator, using the stacked-foil activation technique in combination with high resolution γ -ray spectrometry. The obtained results are comparable to literature data determined via prompt γ -counting and X-ray counting methods. The excitation functions of this work are reproduced well by a model calculation using the code TALYS with a few chosen input parameters. The data should be useful in astrophysical research as well as in production of radionuclides at a small medical cyclotron.

The rapid development of nuclear energy has greatly increased the possibility of nuclear leakage, and the rapid detection of radioactive leakage in emergency situations requires rapid analytical methods. Pu(IV) is almost non-existent in nature, so radioactive contamination in the environment is usually analyzed by detecting the radioactivity level of plutonium. Here, the neutral extractant, PyDAM, and the novel functional ionic liquid, PyDAMI, were synthesized by introducing two amide groups into the pyridine for separating Pu(IV). Due to the high radioactivity of Pu, Pu(IV) was replaced by Th(IV) in extraction experiments. It was found that PyDAM in kerosene or [C 4 mim][NTf 2 ] could not extract Th(IV), U(VI), Eu(III), Ce(IV) and Nd(III) from nitric acid media, while PyDAMI could extract both U(VI) and Th(IV), but hardly extract other metal ions, which indicates that electrostatic interactions play a key role. The distribution coefficients of U(VI) and Th(IV) in PyDAMI/[C 4 mim][NTf 2 ] increase with an increase in the concentration of nitric acid, while they first increase and then decrease in PyDAMI/kerosene, indicating that PyDAMI has different extraction mechanisms in kerosene and [C 4 mim][NTf 2 ] and their respective extraction mechanisms were studied through extraction experiments and some characterization techniques. In addition, the separation performance and separation factor of PyDAMI for thorium and uranium are improved in kerosene. Finally, the effect of temperature on PyDAMI’s ability to extract uranium and thorium was investigated. It was found that the ability of PyDAMI to extract uranium and thorium decreased with increasing temperature, indicating that the extraction of uranium and thorium by PyDAMI was an exothermic reaction.

The structure of Na 3 [UO 2 F 5 ] (I) and CaRb 4 [UO 2 F 4 ] 3 ⋅3H 2 O (II) crystals was studied using X-ray diffraction analysis. The uranium-containing structural units are pentagonal bipyramids [UO 2 F 5 ] 3− , which are isolated from each other in I and linked by bridging fluorine atoms into trinuclear complexes of the composition [(UO 2 ) 3 F 12 ] 6− in II. The latter one fills the existing gap in the crystal chemistry of uranyl fluorides and oxofluorides by representing the first example of a trinuclear complex, while di-, tetra- and pentanuclear complexes have been observed before. The first compound has been known for more than half a century, although here we present the first report on its crystal structure. The crystal chemical formulae of the uranium-containing complexes in I and II are AM 1 5 and A 3 M 2 3 M 1 9 , where A  = UO 2 2+ , М 2 and М 1  = F − . In both structures, the uranyl-containing complexes are linked into 3D frameworks by R –F and R –O coordination bonds with outer-sphere R cations ( R  = Na, Rb or Ca). As both compounds I and II turned out to be non-centrosymmetric their ability to generate the second harmonic was theoretically predicted based on parameters of Voronoi–Dirichlet polyhedra. Experimental verification of the obtained values is of undoubted interest.

In this study, a superabsorbent hydrogel based on Carbopol 940, carboxymethyl cellulose sodium salt (NaCMC), and acrylic acid (C/NaCMC/PAc) was prepared using gamma radiation. This technique serves as a clean and effective method for initiation and crosslinking, intended for agricultural use as a slow-release urea fertilizer. The parameters affecting the gelation percentage, such as Ac and Carbopol contents, as well as different irradiation doses, were studied. The optimal conditions for preparing C/NaCMC/PAc hydrogel were achieved with acrylic acid and Carbopol concentrations of 5 wt% and 3 wt%, respectively, at an irradiation dose of 5 kGy. The swelling rate was enhanced by increasing the Carbopole content, while its degree was enhanced by treating the prepared hydrogel with di-ethanolamine and raising the pH, reaching a swelling degree to 78 g/g. FTIR, XRD, EDX, and SEM were performed to characterize the structure and properties of the fabricated hydrogels. The synthesized hydrogels exhibited excellent urea loading (92 %) and slow release (91 % after 16 days). The extended urea release of Carbopol-co-poly-Ac hydrogels makes them a potential candidate for controlled delivery of urea fertilizer. The data showed that the prepared superabsorbent hydrogel has some advantages and can be used as a slow-release urea fertilizer.

Recently, environmental pollution and inhibition of non-degradable and non-renewable resources have attracted researchers to develop a new kind of natural products. Fibers obtained from natural sources provide certain assistance to synthetic fibers because of their characteristics such as low cost, low density, non-toxicity and similar strength, and they do not encounter any problem during the disposal of materials into the environment. Silver nano-hybrid materials are getting much attention in antibacterial applications, due to its bactericidal nature. In this study, nanosilver-bagasse (Ag-bagasse) fiber as a nanocomposite was successfully prepared by using gamma radiolysis method. The Ag-bagasse fibers were blended with PVA at different weight ratioto improveits physicochemical and antimicrobial capabilities. All prepared films were exposed to 25 kGy of gamma radiation. Various analytical techniques are utilized to investigate the crystal structures, functional groups and surface morphology of the prepared Ag-bagasse fiber and PVA nanocomposite films. XRD shows the formation of silver nanoparticles over bagasse fiber in a single phase with an average crystallite size 10.89 nm. The mechanical properties of nanocomposite films obtained with different amounts of Ag-bagasse fiber reinforcement have been demonstrated. The PVA films were strengthened by the addition of Ag-bagassefiber and the optimum ratio was 5 wt%. Owing to the addition of Ag in the biopolymer matrices, the PVA/8 % Ag-bagasse nanocomposite film demonstrated good antibacterial activity against Escherichia coli , Salmonella typhimurium , Staphylococcus aureus , and Bacillus subtilis . The utilization of bagasse fiber can boost the economic worth of agricultural waste, and the unique characteristics of PVA/Ag-bagasse nanocomposites may find application in the packaging and medical industries.

This study investigates the degradation of crystalline silicon (c-Si) solar cells under high-energy polyenergetic Bremsstrahlung radiation, relevant to space and high-radiation terrestrial environments. Cells were irradiated with doses up to 900 Gy using a clinical linear accelerator (cLINAC). Results demonstrate significant dose-dependent performance loss, with the power conversion efficiency ( η ) decreasing by approximately 7.6 % at the highest dose of 900 Gy. This degradation was driven mainly by reduced short-circuit current density ( J sc ) and increased recombination. External quantum efficiency (EQE) measurements confirmed substantial losses at longer wavelengths, indicating bulk defect generation. Capacitance and conductance analyses revealed the accumulation of deep-level traps and interface states, further elucidating the degradation mechanisms. These findings highlight the vulnerability of c-Si solar cells to Bremsstrahlung exposure and provide critical insights for developing radiation-hardened photovoltaic technologies.

This study investigates the gamma and neutron shielding performance of novel polybenzoxazine (PBz) based composites reinforced with Mo 2 C, Boron, and WS 2 additives. The additives are mixed into the matrix at various mass ratios and then each sample is evaluated in terms of radiation interactions. A three-layered shielding structure was further designed with PBz-Mo2C-25 as the front layer, PBz-B-25 as the intermediate layer, and PBz-WS2-25 as the rear layer. The obtained results show that multi-layer configuration, PBz-3L, further enhanced low-energy neutron attenuation, achieving substantially greater reductions in thermal and epithermal flux compared to single-layer Mo 2 C- and WS 2 -reinforced composites. For photons, the multilayer structure achieves radiation protection efficiency (RPE) values exceeding 99 % at low gamma energies. Total ionizing dose (TID) and displacement per atom (DPA) analyses are also reported. These findings confirm the superior shielding capability of the three-layer composite, highlighting its potential for advanced radiation protection applications in nuclear and aerospace environments.