Photobiocidal-triboelectric nanolayer coating of photosensitizer/silica-alumina for reusable and visible-light-driven antibacterial/antiviral air filters

Outbreaks of airborne pathogens pose a major threat to public health. Here we present a single-step nanocoating process to endow commercial face mask filters with photobiocidal activity, triboelectric filtration capability, and washability. These functions were successfully achieved with a composite nanolayer of silica-alumina (Si-Al) sol-gel, crystal violet (CV) photosensitizer, and hydrophobic electronegative molecules of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOTES). The transparent Si-Al matrix strongly immobilized the photosensitizer molecules while dispersing them spatially, thus suppressing self-quenching. During nanolayer formation, PFOTES was anisotropically rearranged on the Si-Al matrix, promoting moisture resistance and triboelectric charging of the Si-Al/PFOTES-CV (SAPC)-coated filter. The SAPC nanolayer stabilized the photoexcited state of the photosensitizer and promoted redox reaction. Compared to pure-photosensitizer-coated filters, the SAPC filter showed substantially higher photobiocidal efficiency (∼99.99 % for bacteria and a virus) and photodurability (∼83 % reduction in bactericidal efficiency for the pure-photosensitizer filter but ∼0.34 % for the SAPC filter after 72 h of light irradiation). Moreover, after five washes with detergent, the SAPC filter maintained its photobiocidal and filtration performance, proving its reusability potential. Therefore, this SAPC nanolayer coating provides a practical strategy for manufacturing an antimicrobial and reusable mask filter for use during the ongoing COVID-19 pandemic

Vitrification of the Spent Nuclear Fuel Using Iron Phosphate Glasses

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Resonance parameters of Gd isotopes derived from capture measurements at GELINA

Neutron capture yields for Gd-155, Gd-156, Gd-157, Gd-158, and Gd-160 were determined applying the total energy detection principle technique using four C6D6 liquid scintillators and a 10B-loaded ionization chamber. Time-of-flight experiments were carried out at a 30 m flight path station of the GELINA facility using enriched samples. Parameters for resonances in the energy region between 5 and 500 eV were obtained from a resonance shape analysis with REFIT. Resonance integrals for Gd-155 and Gd-157 derived from the parameters are 1511 (25) b and 801 (19) b, respectively. Average level spacings, average radiation widths and neutron strength functions were derived. The results were compared with data that are reported in the literature and recommended in evaluated data libraries.11Nsciescopu

Resonance parameters of Gd isotopes derived from capture measurements at GELINA

Neutron capture yields for 155Gd, 156Gd, 157Gd, 158Gd, and 160Gd were determined applying the total energy detection principle technique using four C6D6 liquid scintillators and a 10B-loaded ionization chamber. Time-of-flight experiments were carried out at a 30 m flight path station of the GELINA facility using enriched samples. Parameters for resonances in the energy region between 5 and 500 eV were obtained from a resonance shape analysis with REFIT. Resonance integrals for 155Gd and 157Gd derived from the parameters are 1511 (25) b and 801 (19) b, respectively. Average level spacings, average radiation widths and neutron strength functions were derived. The results were compared with data that are reported in the literature and recommended in evaluated data libraries.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Photo-neutron reaction cross-sections of

The flux-weighted average cross-sections for the 59Co($\gamma$, xn)58-55Co reactions have been measured with the bremsstrahlung end-point energies of 65 and 75 MeV by using the activation method in combination with the off-line $\gamma$-ray spectrometry. The measured cross-sections for the $(\gamma,\mathrm{n})$, $(\gamma,2\mathrm{n})$, $(\gamma,3\mathrm{n})$ and $(\gamma,4\mathrm{n})$ reactions of 59Co at 65 MeV are $15.828\pm 0.491$, $5.003\pm 0.206$ , $0.408\pm 0.047$ and $0.039\pm 0.008$ mb, whereas at 75 MeV are $15.653\pm 0.361$, 4.965±0.289, $0.389\pm 0.062$ and $0.036\pm 0.007$ mb, respectively. The 59Co($\gamma$, xn) reaction cross-sections as a function of photon energy were also theoretically simulated by using TALYS 1.9 code. Then the flux-weighted average cross-sections at different bremsstrahlung energies were obtained from the theoretical values and the literature data at lower energy based on mono-energetic photons. The present data are measured for the first time and are found to be in good agreement with the theoretical flux-weighted average values. It was found that the 59Co($\gamma$, xn)58-55Co reaction cross-sections increase from their threshold values to a certain bremsstrahlung energy. After a certain energy, the individual 59Co($\gamma$, xn) reaction cross-sections decrease with the increase of bremsstrahlung energy due to opening of other reaction channels. These two observations indicate the role of excitation energy and its partition in different reaction channels. All the four cobalt isotopes produced from the 59Co($\gamma$, xn) reactions have medical and other applications

Yield ratios of the isomeric pair 85 m,gSr formed in natSr(γ,xn) reactions

The yield ratios of 85m,gSr were measured in the natSr(γ,xn)85m,gSr reactions with the bremsstrahlung end-point energies of 55-, 60-, and 65-MeV. The experiment was carried out by the activation method in combination with high resolution HPGe γ-ray spectroscopy. In order to improve the accuracy of the experimental results, appropriate experimental procedure was used to reduce the influence of the strong annihilation peak (511 keV) to the 514 keV γ-ray peak of 85gSr. The experimental results are compared to theoretical predictions using code TALYS- 1.6. The present results for 55-, and 60-MeV bremsstrahlung end-point energies have been measured for the first time.11Nsciescopu

Measurement of flux-weighted average cross sections of

The flux-weighted average cross sections of ^{\mathrm {nat}}\hbox {In}(\upgamma ,x\hbox {n}) reactions and isomeric yield ratios of $$^{112\mathrm {m,g}}\hbox {In}$$, $$^{111\mathrm {m,g}}\hbox {In}$$, and $$^{110\mathrm {m,g}}\hbox {In}$$ were measured with the bremsstrahlung end-point energies of 50, 60, and 70 MeV using an activation and off-line \upgamma -ray spectrometric technique at the Pohang Accelerator Laboratory (PAL), Korea. It was observed that the average cross sections of the ^{\mathrm {nat}}\hbox {In}(\upgamma ,\hbox {xn}) reactions increase with bremsstrahlung energy up to the Gaint Dipole Resonance (GDR) region. Thereafter, it shows a small decrease trend with bremsstrahlung energy due to the opening of another reaction channel. The isomeric yield ratios of same product in the (\upgamma ,\hbox {n}), (n,2n), (p,x), (\upalpha ,\hbox {x}), and $$(^{{3}}\hbox {He},\hbox {x})$$ reactions for various targets show that the spin of the target nucleus plays a vital role besides the effect of excitation energy and input angular momentum in determining the isomeric yield ratios

Activity concentrations and radiological hazard assessments of 226Ra, 232Th, 40K, and 137Cs in soil samples obtained from the Dongnam Institute of Radiological & Medical Science, Korea

The radioactivity concentration of environmental radionuclides was analyzed for soil and sand at eight locations within a radius of 255 m centered on the Dongnam Institute of Radiological & Medical Science (DIRAMS), Korea. The average activity concentrations of 40K, 137Cs, 226Ra, and 232Th were 661.1 Bq/kg-dry, 0.9 Bq/kg-dry, 21.9 Bq/kg-dry, and 11.1 Bq/kg-dry, respectively. The activity of 40K and 137Cs was lower than the 3-year (2017–2019) average reported by the Korea Institute of Nuclear Safety, respectively. Due to the nature of granite-rich soil, the radioactivity of 40K was 0.6-fold higher than in other countries, while 137Cs was in the normal fluctuation range (15–30 Bq/kg-dry) of the concentration of radioactive fallout from nuclear tests. The activity of 226Ra and 232Th was lower than in Korean soils reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average activity concentrations of 232Th and 40K for the soil and sand samples from DIRAMS were within the range specified by UNSCEAR in 2000. The radium equivalent activity and internal and external hazard index values were below the recommended limits (1 mSv/y). These radionuclide concentration (226Ra, 232Th, 40K, and 137Cs) data can be used for regional environmental monitoring and ecological impact assessments of nuclear power plant accidents

Thermal neutron coss-section and resonance integral of the 152Sm(n,Gamma)153Sm reaction induced by pulsed neutron

We measured the thermal neutron cross-section (sigma(0)) and resonance integral (I-0) of the Sm-152(n,gamma)Sm-153 reaction relative to that of the Au-197(n,gamma)Au-198 reaction. Sm and Au foils with and without a cadmium cover of 0.5 mm were irradiated with moderated pulsed neutrons produced from the electron linac. The induced activities of the reaction products were determined via high energy resolution HPGe detector. The present results: sigma(0),(sm) = 212 +/- 8 b and sigma(0),(sm) = 3.02 +/- 0.19 kb are consistent with most of the existing reference data.1110sciescopu

Measurement of isomeric yield ratios of Rh-99m,Rh-g;101m,Rh-g;102m,Rh-g in the (nat)pd(gamma, pxn) reactions with the bremsstrahlung end-point energies of 50-70 MeV

The isomeric yield ratios of Rh-99m,Rh-g, Rh-101m,Rh-gg, and Rh-102m,Rh-g isomeric pairs produced from the (nat)pd(gamma,pxn) reactions were measured with the bremsstrahlung end-point energies of 50-, 55-, 60-, 65-, and 70-MeV at the 100 MeV electron linac of the Pohang Accelerator Laboratory, Korea. The measurements were carried out with the activation method in combination with off-line gamma-ray spectrometry. In order to improve the accuracy of the activity measurements, the separation of the overlapping gamma-rays and the necessary corrections for the counting losses were made. The new experimental results are compared with the theoretical values of the TALYS-1.6 code.111sciescopu