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A ubiquitous distribution of plastic debris has been reported in aquatic and terrestrial environments; however, the interactions between plastics and radionuclides and the radioactivity of environmental plastics remain largely unknown. Here, we characterize biofilms developing on the surface of plastic debris to explore the role of plastic-associated biofilms as an interaction medium between plastics and radiocesium (137Cs) in the environment. Biofilm samples were extracted from plastics (1–50 mm in size) collected from two contrasting coastal areas in Japan. The radioactivity of plastics was estimated based on the 137Cs activity concentration of the biofilms and compared seasonally with surrounding environmental samples (i.e., sediment and sand). 137Cs traces were detected in biofilms with activity concentrations of 21–1300 Bq·kg−1 biofilm (dry weight), corresponding to 0.04–4.5 Bq·kg−1 plastic (dry weight). Our results reveal the interaction between 137Cs and plastics and provide evidence that organic and mineral components in biofilms are essential in 137Cs retention in environmental plastics. Given the ubiquitous distribution of plastic debris in the environment, more attention should be directed to bioaccumulation and the radioecological impacts of plastic-associated radionuclides on ecosystems. [ABSTRACT FROM AUTHOR]

The ceramic products derived from cesium-strontium co-doped geopolymers ((Cs, Sr)-GP) have been synthesized by microwave sintering to realize the co-immobilization of Cs and Sr. Results show that (Cs, Sr)-GP with various Cs/Sr ratios (2–4) form Sr-feldspar-pollucite composite ceramic, the formation temperatures of monoclinic Sr-feldspar decrease from 1000 ℃ (for Sr-GP) to 800 ℃ (for (Cs, Sr)-GP) with Cs addition. The ceramic product heat treated from the (4Cs, Sr)-GP at 1000 ℃ has a high crystalline and optimal leaching resistance, is considered as an ideal host to immobilization the real fission products containing Cs and Sr. [ABSTRACT FROM AUTHOR]

The spent alum sludge was employed for the removal of specific fission products including 137Cs, 85Sr, 152+154Eu, 99Mo, and 99Tc radionuclides from radioactive waste. The physicochemical features of spent alum sludge were investigated. The results illustrated that the uptake percentages were 94.2, 90.5, 87.6, 87.1, and 76.6%, correspondingly, for 99Mo, 152+154Eu, 99Tc, 85Sr, and 137Cs. The kinetic studies illustrated that the adsorption process obeyed Langmuir kinetics which is a combination of first-order and second-order expressions. The findings demonstrated that the spent alum sludge can be applied successfully as a low-cost and effective adsorbent for the treatment of radioactive waste. [ABSTRACT FROM AUTHOR]

Materials containing mixed anions, particularly, oxyhalides containing asymmetric functional building units, may lead to the discovery of excellent nonlinear optical (NLO) materials. In the present work, the geometric structure, mechanical properties, electronic structure and optical properties of two d 0– d 10 electron transition-metal oxyhalides Cs2CdV2O6Cl2 and Cs3CdV4O12Br have been systematically determined based on density functional theory. The asymmetric functional building units [V2O7], [V4O13], [CdO2Cl4] and [CdO4Br2] exhibit varying degrees of second-order Jahn−Teller distortions, contributing differently to the macroscopic nonlinearity. Mechanical properties reveal that the two oxyhalides are structurally and mechanically stable. Detailed electronic and optical properties of the two oxyhalides are provided. Optical anisotropy character is exhibited along different polarization vectors, giving a large birefringence for satisfying the phase-matching condition. Maximum absolute values of static second harmonic generation (SHG) coefficients are 4.47 pm V−1 for Cs2CdV2O6Cl2 and 3.72 pm V−1 for Cs3CdV4O12Br, suggesting that Cs2CdV2O6Cl2 and Cs3CdV4O12Br are potential NLO crystals with large SHG coefficients. In particular, unique 3D framework structures give a polar structure superposition of individual moments for asymmetric functional building units. Thus, maximum magnitudes of the total microscopic dipole are achieved, having the largest influence on the SHG response. This study elucidates the relationship between the structure and properties of transition-metal oxyhalides, providing valuable insights for designing NLO materials with excellent performance. [ABSTRACT FROM AUTHOR]

The structural flexibility of the perovskite blocks in the Dion-Jacobson family of layered perovskite oxides has successfully resulted in the generation of KPrNa n-2 Nb n O 3n+1 and KPrCa n-2 Nb 2 Ti n-2 O 3n+1 (n = 3, 4). The stabilization of K+ ions preferring a six coordination in the interlayer region is significant compared to the facile formation of layered perovskite oxides possessing bigger Rb+ or Cs+ ions with an eight coordination in the interlayer. The structure of the n = 3 members, KPrNaNb 3 O 10 (S. G. Cmcm ; a = 3.8858(1) Å, b = 29.6553(9) Å, c = 7.7635(3) Å) and KPrCaNb 2 TiO 10 (S. G. Cmcm ; a = 3.8634(2) Å, b = 29.4808(2) Å, c = 7.6945(5) Å) were confirmed respectively using the Rietveld and Le Bail methods utilizing the powder X-ray diffraction data. The n = 4 members, KPrNa 2 Nb 4 O 13 and KPrCa 2 Nb 2 Ti 2 O 13 are synthesized through high-temperature ceramic methods. The compounds are phase pure as confirmed from the X-ray diffraction data and were characterized by UV–visible diffuse reflectance measurements. These two-dimensional oxides also undergo facile topochemical ion-exchange and intercalation reactions and opens up several interesting possibilities. We have replaced the K+ ions in the interlayer by H+, Li+, Na+ ions and [CuCl]+ groups through low temperature reactions. The usefulness of various Dion-Jacobson layered perovskite oxides for potential photocatalytic applications has been explored by determining the optical band gaps, the valence band, and the conduction band energy levels based on the UV–visible diffuse reflectance measurements. [ABSTRACT FROM AUTHOR]

An advanced solvent has been developed for application in the extraction of cesium from alkaline nuclear waste. Four lipophilic guanidines have been compared to arrive at a more hydrolysis-resistant suppressor component of the solvent. Plans call for deployment of the Next-Generation Caustic Side-Solvent Extraction (NG-CSSX) process at industrial scale for separation of radioactive Cs-137 from the legacy salt waste stored at the US Department of Energy Savannah River Site (SRS). In the solvent used in NG-CSSX, an alkyl guanidine "suppressor" component facilitates efficient stripping of the loaded cesium from the solvent. However, as typical of guanidine compounds, the suppressor previously used in the NG-CSSX solvent, N,N',N"-tri(3,7-dimethyloctyl)guanidine (TiDG), suffers from hydrolytic degradation under process conditions. Recently, the sterically hindered alkyl guanidine N,N'-dicyclohexyl-N"-(10-nonadecyl)guanidine (DCNDG) has been found to offer 8 to 44 times greater hydrolysis resistance than TiDG. Here, the process performance characteristics of the NG-CSSX solvent incorporating DCNDG are determined in comparison with TiDG and two other guanidine suppressors. The solvent has been adjusted in density to accommodate use in the SRS Salt Waste Processing Facility and tested under aggressive bench-scale conditions intended to increase plant throughput. Experiments include the effect of ageing at normal and off-normal temperatures of the distribution of Cs+ through the NG-CSSX process, the fate and effects of guanidine degradation products, suppressor capacity, coalescence times for aqueous-solvent dispersions, tendency for emulsification, third-phase formation, and degree of protonation of the guanidine in stripping. While the chosen structures of the four compared guanidines mainly effect differences in stability, subtle differences in other system properties such as emulsion formation and suppressor capacity provide insight into the function of this important solvent component. In comparison with TiDG and two other guanidines, DCNDG provides greatly increased stability while not compromising the excellent functional properties of the NG-CSSX solvent. [ABSTRACT FROM AUTHOR]

This present investigation delves into the intricate 210Pb and 137Cs radionuclides dating to govern the study of sedimentation rate, age modeling, and lifespan of the Perumal lake in the Cuddalore district, Tamil Nadu. In the study area, the 01 core sediment was excavated at the length of 51 cm, and concern for the 210Pb and 137Cs radionuclides dating using an Alpha spectrometer 7200-04 and a Gamma-ray spectrometer GC-3520 instruments. From the robust outcome, the bathymetry survey investigates the bottom topography, with a mean depth of 3.1 m and a maximum length of 11.54 km. Subsequently, the mean value of bulk density, porosity, and water content in the vertical profile of the sediment esteems as 1.52 g/cm3, 32.47 g/cm3, and 1.61%, and sediment textures unveils predominately consists of clay composition and attributes with higher content of 210Pb radionuclide in the sediments to affirms the rate and accumulation of the sediments in the aquatic environment. From the Constant Rate Supply (CRS) method, the 210Pb radionuclide activity shows the mean accumulation rate (kg/m2/year) and sedimentation rate (cm/year) indicates 0.57 ± 0.05 (kg/m2/year) and 0.84 ± 0.07 (cm/year) dated since 1944AD to 2023AD. The mean sedimentation rate of 137Cs radionuclides activity for 1963AD and 1986AD implies 0.57 ± 0.04 (cm/year) and 0.43 ± 0.03 (cm/year). From the computation, the lifespan of the lake is 369.05 years and 543.86 years with respect to 210Pb and 137Cs activities, respectively. The sedimentation rate is crucial in diminishing the lake from the future accumulation of water and sediments in the aquatic environments. [ABSTRACT FROM AUTHOR]

Monitoring of the anthropogenic radionuclides (90Sr, 135Cs and 137Cs) in different components such as spinach, milk, meat, soil and the grass is important for the environmental radiological survey. Nuclear weapons testing in the atmosphere, nuclear power plant accidents and leaks from the nuclear fuel cycle are the main sources of these radionuclides. The amounts of 90Sr/90Y detected in the environment are mostly due to fallout from nuclear weapons testing. Because of its long physical (28.5 years) and biological half-lives (approximately 12 years) and high fission yield, the measurement of 90Sr is also necessary for radiation protection purposes. It accumulates in bone tissue when ingested by humans through the food chain, and 90Y, a daughter nuclide of 90Sr, emits high-energy beta particles, raising the risk of bone cancer. Strontium has been widely measured in milk samples by using various classical methods. In this study, the procedure we used is based on the separation of 90Y by HDEHP extraction and counting the Cherenkov radiation using a liquid scintillation spectrometer, Quantulus 1220. Prior to analyses, spiked milk samples were dried and prepared as milk powder. The microwave ashing programme was optimised, and recovery of the radiochemical separation steps was tested for spiked milk powder samples before routine analysis. This method is found to be applicable for the routine analysis of 90Sr in milk samples after validation of the method by measuring IRMM milk powder samples, too. A lower limit of detection of about 0.02 Bq.kg−1 was obtained for samples in the case of 84–99% Y chemical yield, 1.45 cpm reagent blank, 4 × 60 minutes counting time and about 83.5 ± 2.1% counting efficiency. [ABSTRACT FROM AUTHOR]

• PB/SiO 2 -NH 2 NFs reached the maximum adsorption capacity of 111.38 mg/g. • APTES is used as a bridge between silica nanofibers and PB. • A synergistic effect of aminoated silica and Prussian blue was observed during cesium removal. • PB/SiO 2 -NH 2 NFs can be used for practical separation of radioactive liquid waste. • The modification strategy is universal to other high performance fibers. To improve the selective separation performance of silica nanofibers (SiO 2 NFs) for cesium ions (Cs+) and overcome the defects of Prussian blue nanoparticles (PB NPs), PB/SiO 2 -NH 2 NFs were prepared to remove Cs+ from water. Among them, 3-aminopropyltriethoxysilane (APTES) underwent an alkylation reaction with SiO 2 , resulting in the formation of a dense Si-O-Si network structure that decorated the surface of SiO 2 NFs. Meanwhile, the amino functional groups in APTES combined with Fe3+ and then reacted with Fe2+ to form PB NPs, which anchored firmly on the aminoated SiO 2 NFs surface. In our experiment, the maximum adsorption capacity of PB/SiO 2 -NH 2 NFs was 111.38 mg/g, which was 31.5 mg/g higher than that of SiO 2 NFs. At the same time, after the fifth cycle, the removal rate of Cs+ by PB/SiO 2 -NH 2 NFs adsorbent was 75.36% ± 3.69%. In addition, the adsorption isotherms and adsorption kinetics of PB/SiO 2 -NH 2 NFs were combined with the Freundlich model and the quasi-two-stage fitting model, respectively. Further mechanism analysis showed that the bond between PB/SiO 2 -NH 2 NFs and Cs+ was mainly a synergistic action of ion exchange, electrostatic adsorption and membrane separation. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the operating characteristics of a chemisorption heat pump. 1-D transient model of a chemisorption heat pump was developed, for which an analysis of four alternating modes of operation was performed. The performance was analyzed with respect to the operating time of the adsorption and desorption operation modes during alternating operations, and the results showed that the cooling capacity has an optimum point depending on the operating times. It was also confirmed that the coefficient of performance increases as the operating time increases. The system performance was also analyzed according to the flow rates of the secondary fluids supplied to the main components. As the flow rates of the secondary fluids supplied to the main components increased, the cooling capacity improved, and the coefficient of performance was found to be compounded by the secondary flow conditions and the operating times of the adsorption and desorption operation modes. Based on the results, it was found that the cooling capacity, coefficient of performance, and specific cooling power of the chemisorption heat pump can be operated in a large range from 876.7 to 3070.0 W, 0.13 to 0.32, and 39.3 to 137.7 W/kg, respectively, depending on the operating conditions. [ABSTRACT FROM AUTHOR]

Recently declassified material and other information that has never before appeared in the public domain allow the authors to explain some of the workings of the Nuclear Emergency Support Team (NEST)—often one of the first units to respond whenever there is a nuclear incident, whether it involves a nuclear reactor or a nuclear weapon. Long the subject of mystique, NEST is often depicted on screen as a secretive government unit with highly specialized capabilities and harrowing missions. The reality is at once more mundane and more remarkable. Formed in the 1970s in response to a spate of nuclear blackmail attempts, NEST has been at the center of every major nuclear event from the accident at Three Mile Island to the disaster at Fukushima. Other operations, unknown to the public, are described here for perhaps the first time. Historical accounts provide a glimpse into the breadth of the organization's missions, from neutralizing terrorist nuclear devices to responding to nuclear reactor accidents. The diversity of NEST's missions and the uniqueness of its scientific capabilities set the unit apart as a national asset. [ABSTRACT FROM AUTHOR]

The possibility of using ferrocyanide sorbents NPF-HTD, NPF-C, and T-35 for cesium concentration in the method of 137Cs determination in natural and waste waters has been investigated. Differences in sorption characteristics of sorbents and conditions of cesium concentration to achieve a chemical yield of 98–99% in the concentrate have been revealed. A variable method for determination of 137Cs in natural and waste waters has been developed, taking into account the ratio of sample volume and sorbent mass in the column, the efficiency of 137Cs detection, and the time of concentrate measurement to achieve the minimum detectable activity of 137Cs in the sample of 0.001–0.01 Bq/L. The method was tested for determination of 137Cs in waters of natural reservoirs and rivers in the territories of Sverdlovsk oblast and Chelyabinsk oblast, as well as waters of monitoring wells in the territories of long-term storage and disposal of radioactive waste. The data on the composition of river and reservoir waters are presented, and the dependence of the cesium chemical yield into the concentrate on the concentration of macrocomponents in samples is shown. [ABSTRACT FROM AUTHOR]

It has been shown that, after the shutdown of the nuclear reactor at the Rosatom Mining and Chemical Combine (MCC) in 2010, anthropogenic radionuclides (60Co, 137Cs, 152Eu, and 241Am) are still detected in the bottom sediments (BS) of the Yenisei River in the MCC-affected area. Data from a comparative analysis of the potential mobility of anthropogenic radionuclides in the Yenisei BS surface and lower layers long after the shutdown of the MCC nuclear reactor are presented for the first time. The mobility of radionuclides was estimated using the well-known procedure of sequential extraction of BS. For 60Co, an increase in potential mobility in the lower layers (which are earlier in time of formation) was shown compared to the upper ones for the first time. The radionuclide 137Cs retains high binding strength to mineral matter of BS (close to 100%) regardless of the time factor. The long-term preservation of the high potential mobility of the radionuclides 241Am and 152Eu in BS, as well as the increase in potential mobility of 60Co over time, for the first time makes it possible to consider these radionuclides as potentially bioavailable in the ecosystem of the Yenisei River. [ABSTRACT FROM AUTHOR]

Rare earth ions with d-f transitions (Ce3+, Eu2+) have emerged as promising candidates for electroluminescence applications due to their abundant emission spectra, high light conversion efficiency, and excellent stability. However, directly injecting charge into 4f orbitals remains a significant challenge, resulting in unsatisfied external quantum efficiency and high operating voltage in rare earth light-emitting diodes. Herein, we propose a scheme to solve the difficulty by utilizing the energy transfer process. X-ray photoelectron spectroscopy and transient absorption spectra suggest that the Cs3CeI6 luminescence process is primarily driven by the energy transfer from the I2-based self-trapped exciton to the Ce-based Frenkel exciton. Furthermore, energy transfer efficiency is largely improved by enhancing the spectra overlap between the self-trapped exciton emission and the Ce-based Frenkel exciton excitation. When implemented as an active layer in light-emitting diodes, they show the maximum brightness and external quantum efficiency of 1073 cd m−2 and 7.9%, respectively. Rare-earth metal halide perovskites are promising for deep blue LEDs. Here, Yang et al. report energy transfer between self-trapped exciton and Frenkel exciton in Cs3CeI6 by adding excess CsI during thermal evaporation, resulting in deep blue LEDs with external quantum efficiency of 7.9% at 424 nm. [ABSTRACT FROM AUTHOR]

This paper presents research on the assessment of the radioecological state of plant cover surrounding two research reactor facilities located within the Semipalatinsk Test Site (STS) as examples of nuclear fuel cycle facilities (NFC). Source data on the concentrations of artificial radionuclides in the plant cover were obtained. Quantitative values for 137Cs, 241Am, and 239+240Pu activity concentrations were determined in plants across the perimeters of the facilities, indicating that these compounds may be present in the associated media from the perspective of accumulative bioindication. The values determined for artificial radionuclides in the 'soil‒plant' system around the researched NFC facilities were attributed to radioactive contamination of the STS territory. [ABSTRACT FROM AUTHOR]

The determination of the semiconducting materials performance heavily relies on the diffusion coefficient and length of the carrier. Recently, significant progress is made in enhancing solar cell efficiency through improved carrier diffusion in perovskite thin films. However, the spatial‐temporal mechanisms underlying carrier transport remain unclear. Recent advancements in utilizing transient absorption microscopy (TAM) offer promising opportunities to directly visualize the carrier transport dynamics within perovskite films. Here, the wide‐field imaging TAM combined with X‐ray diffraction and scanning electron microscopy is employed to investigate the spatial‐temporal carrier transport dynamics in FA1−xCsxPbI3 perovskites with varying Cs doping ratios. The experimental results indicate that the diffusion constant remains consistent regardless of the excitation power. Moreover, a decrease in the Cs doping ratio leads to an increase in the diffusion length within FA1−xCsxPbI3 perovskites. The measurements reveal a highest diffusion coefficient of up to 0.085 cm2 s−1 and a maximum diffusion length of ≈1.4 µm in FA0.97Cs0.03PbI3. Comparative analysis of short‐circuit current density, open‐circuit voltage, fill factor, and power conversion efficiency demonstrates that FA0.97Cs0.03PbI3 exhibits superior device efficiency. The TAM visualizes spatial/ temporal carrier diffusion dynamics, showing a significant correlation with device efficiency and thus providing valuable insights for further enhancing device performance. [ABSTRACT FROM AUTHOR]

The large size (4 cm × 4 cm × 1 cm) Ce3+-doped high gadolinium oxyfluoride glass with density of 5.83 g/cm³ was prepared by the melt quench method at 1220 °C. The glass is colorless and transparent over the visible range. The prolonged decay time under 275 nm UV light demonstrates the energy transfer from Gd3+ ions to Ce3+ ions. The X-ray excited luminescence spectra (XEL) show the emission peak corresponds to the 5d→4f transitions of Ce3+ ion. The integral emission intensity of glass was compared with that of bismuth germanate oxide (BGO) crystals. The scintillation property of glass was studied under the γ -ray from 137Cs source and a clear energy peak was observed with light yield (LY) over 1100 ph/MeV. The scintillation decay time comprises fast and slow components. All results presented in this work indicate the appropriate potential to be high-energy rays detecting material for CEPC. [ABSTRACT FROM AUTHOR]

The results of the sorption of 137Cs from the clarified phase of accumulated high-level alkaline radioactive waste of the Mayak Production Association with sorbents based on modified nickel ferrocyanide (Fersal) and resorcinol–formaldehyde resin (RFS-I) in batch and flow conditions are presented. In batch mode, the distribution coefficient of 137Cs on Fersal and RFS-I sorbents is 2300 and 730 cm3/g, respectively. In flow mode, the volume of the passed solution before the 137Cs breakthrough for Fersal and RFS-I sorbents is 140 and 85 column volumes, and the maximum purification factor is 104 and 103, respectively. To desorb cesium from the Fersal and the RFS-I, 8 M HNO3 and 1 M HNO3 solutions, respectively, were used. A decrease in the sorption characteristics of the RFS-I sorbent during the sorption of cesium from high-level alkaline radioactive waste was discovered. A conclusion was made about the possibility of using the Fersal sorbent for the recovery of 137Cs from high-level alkaline radioactive waste of the Mayak Production Association. [ABSTRACT FROM AUTHOR]

Based on the Weather Research and Forecasting Model Coupled with Chemistry (WRF-Chem) atmospheric chemistry model, a parameterization scheme for the radioactive isotope caesium (137Cs), considering processes such as advection, turbulent diffusion, dry deposition, and wet deposition, was constructed, enabling the spatial distribution simulation of the concentration and deposition of 137Cs. The experimental simulation studies were carried out during the high emission period of the Fukushima nuclear accident (from 11 to 17 March 2011). Two sets of comparison experiments, with or without deposition, were designed, the effects of wind field and precipitation on the spatial transport and ground deposition of 137Cs were analyzed, and the influence of wind field and precipitation on 137Cs vertical transport was analyzed in detail. The results indicate that the model can accurately simulate the meteorological and 137Cs variables. On 15 March, 137Cs dispersed towards the Kanto Plain in Japan under the influence of northeastern winds. In comparison to the experiment without deposition, the concentration of 137Cs in the Fukushima area decreased by approximately 286 Bq·m−3 in the deposition experiment. Under the influence of updrafts in the non-deposition experiment, a 137Cs cloud spread upward to a maximum height of 6 km, whereas in the deposition experiment, the highest dispersion of the 137Cs cloud only reach a height of 4 km. Affected by the wind field, dry deposition is mainly distributed in Fukushima, the Kanto Plain, and their eastern ocean areas, with a maximum dry deposition of 5004.5 kBq·m−2. Wet deposition is mainly influenced by the wind field and precipitation, distributed in the surrounding areas of Fukushima, with a maximum wet deposition of 725.3 kBq·m−2. The single-station test results from the deposition experiment were better than those for the non-deposition experiment: the percentage deviations of the Tokyo, Chiba, Maebashi, and Naraha stations decreased by 61%, 69%, 46%, and 51%, respectively, and the percentage root mean square error decreased by 46%, 25%, 38%, and 48%, respectively. [ABSTRACT FROM AUTHOR]

The article discusses the use of tritium (3 H) and cesium (137 Cs) as temporal markers in ice cores extracted from temperate glaciers. We present a complete tritium profile for a 46 m ice core drilled from the Adamello Glacier, a temperate glacier in the Italian Alps, and compare it to the 137 Cs profile from the same ice core. Our analysis reveals tritium contamination between 19 and 32 m of depth, which can be attributed to the global radioactive fallout caused by atmospheric nuclear-bomb testing that took place in the 1950s and 1960s. Results show that the radioactive peak associated with 1963 does not occur at the same depth for both 3 H and 137 Cs; instead, the tritium peak is 1.5 m above the cesium one. Our hypothesis is that this misalignment is caused by meltwater-induced post-depositional processes that affect 137 Cs, which is more sensitive to percolation than 3 H. The total inventory of 137 Cs in this ice core is also among the lowest ever reported, providing additional evidence that the presence of meltwater has affected the distribution of this radionuclide within the ice. In contrast, the total tritium inventory is comparable to what is reported in the literature, making it a more reliable temporal marker for temperate glaciers. [ABSTRACT FROM AUTHOR]

This research investigates the influence of synthesis kinetics on the structural and photocatalytic properties of chitosan–clay nanocomposites (Cs/MMT) and chitosan–hectorite nanocomposites (Cs/HET), employing an optimized initial stoichiometry of 1:3. Utilizing a variety of analytical techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR), the study explores the structural evolution of the nanocomposites and their photocatalytic performance using semiconductor catalysts TiO2 and ZnO. The findings emphasize the significant impact of reaction kinetics, particularly after 3 h of reaction time, on the structural features of the nanocomposites. Notably, Cs/MMT demonstrates greater crystalline stability compared to Cs/HET due to variations in octahedral cavity occupancy in the initial clays. FTIR and TEM analyses depict the progressive evolution of the nanocomposites during the reaction, shedding light on how reaction kinetics drive the formation of specific bonds within the nanocomposites. In terms of photocatalytic activity, this study provides insights into the complex dynamics of photocatalytic degradation, with a specific focus on the performance of TiO2 and ZnO under diverse experimental conditions. The superior efficacy of TiO2 as a catalyst, particularly when integrated with Cs/MMT nanocomposites, is unequivocally demonstrated, with degradation rates exceeding 80%. This preference stems from TiO2 consistently exhibiting higher degradation rates compared to ZnO, attributed to structural disparities between montmorillonite and hectorite, influencing catalyst–support interactions. The findings underscore the critical importance of selecting suitable catalyst and support matrix combinations for optimizing performance in specific applications. [ABSTRACT FROM AUTHOR]

Photovoltaic devices fabricated using mixed-cation halide perovskites have demonstrated a superior combination of high efficiency and long operating life. In this study, we synthesize a series of mixed-cation halide perovskites with the composition of MA1−xCsxPbBr3 (MA = CH3NH3), where x varies from 0 to 1. We carefully examine various polar solvents and develop a relatively facile, room temperature solution-based growth method for growing these single crystals under optimal conditions. We conduct a comprehensive investigation of the influence of the Cs+ cation on the structure and optical properties of the perovskite solid solutions. The structural characterization using X-ray diffraction confirms the successful substitution of cesium for the methylammonium (MA) cation in the MA1−xCsxPbBr3 perovskite structure, with a continuous solubility. As the Cs+ content increases, the crystal structure undergoes a gradual transformation from a cubic phase (for MAPbBr3) to an orthorhombic phase (for CsPbBr3). To study the impact of Cs substitution on their optical properties, we perform UV–Vis absorption analysis, and find no significant change in the bandgap value, which remains approximately 2.12–2.14 eV for the compositions with x up to 0.7. For x > 0.7, however, the bandgap value gradually increases to reach 2.21 eV for pure CsPbBr3. This work demonstrates a valid technique for the growth of halide perovskite solid solution crystals, which can be a versatile tool for tailoring the structure, long-term stability, and optoelectronic properties for advanced photovoltaic applications. [ABSTRACT FROM AUTHOR]

This study presents a proposal for a method that uses a digital portfolio for developing self-regulated learning among engineering students with two main objectives: 1) to design a method for the self-regulated development of a digital portfolio and 2) to propose an instrument that allows measuring self-regulated development using a digital portfolio. The design-based research approach is applied with a case study having a sample of 137 students. Data are gathered at the beginning and at the end of a semester. As a result, seven workshops, the measurement instrument, and the case study are described. It is observed that there is an increase in medians from the beginning to the end of the semester, showing the teaching of concepts and processes necessary for self-regulated learning. In conclusion, the self-regulated method for developing a digital portfolio is a solution that allows fomenting self-regulation among students by applying planning, learning strategies, and reflective thinking. [ABSTRACT FROM AUTHOR]

High purity germanium (HPGe) detectors are deployed globally for gamma-radiation spectroscopy due to their superior energy resolution. In this work, the essential characteristics of n and p-type HPGe detectors, such as energy resolution, efficiency, minimum detectable activity (MDA), and peak shape were studied for the purpose of characterization and performance optimization. The results are obtained for various source-detector configurations in a wide energy range of 40–1408 keV using gamma sources, such as 109Cd, 57Co, 137Cs, 54Mn, 65Zn, 60Co, and 152Eu. Scanning (distance, lateral, and radial) of the detectors was performed using different gamma sources to understand the orientation of the crystal with its active volume and counting efficiency and to characterize the geometry in detail. The ambient background around the n-type HPGe was reduced using Pb-shielding. As a result, an 85.85% suppression was observed in the mean integral window of 40–2700 keV. The characterization and performance tests of the detectors convincingly suggest that both the detectors can be deployed for environmental radioactivity explorations. [ABSTRACT FROM AUTHOR]

Intensive formation of organic deposits in the tubing of an oil production well is one of the most serious complications in oil production. An important task is to correctly assess the effectiveness of the methods used to combat the deposits in question. Field diagnostics of the condition of the inner surface of the production tubing is carried out by evaluating indirect parameters that do not allow evaluating the distribution of deposits along the production tubing. With the aim of solving these problems the authors of this work have developed a method for monitoring the formation of deposits on the inner surface of the tubing on the basis of the 'thermal analogy' mechanism. The applicability of the technology was evaluated at the Wax Flow Loop laboratory stand. The developed mathematical model for calculating the dynamics of sediment formation based on the temperature parameters of the flow significantly correlates with the data obtained using the basic barometric method. The use of this technology will make it possible to increase the efficiency of oilfield equipment, reduce the accident rate of production, more correctly select methods for combating wax deposition and evaluate their effectiveness. [ABSTRACT FROM AUTHOR]

This paper presents a quantitative risk assessment method to predict the potential risks of liquid ammonia tanks. The method combines probabilistic prediction and consequence assessment: the former is predicted by Bayesian networks derived from bow‐tie mapping, in which the conditional probabilities are determined by analytic hierarchy process, the latter is calculated based on numerical simulation of accident consequences and Probit probability model. The application results show that the method can be used for quantitative risk assessment of liquid ammonia storage tank, and the Bayesian network model is efficient and stable, which can realize risk prediction, accident causes analysis and risk mitigation analysis. Human errors during production or maintenance and corrosion are the main causes of liquid ammonia leakage. Toxicity has the greatest effect on the risk of liquid ammonia tanks. Risk mitigation measures can significantly reduce individual risk and societal risk. The obtained results provide meaningful guidance for the prevention and risk mitigation strategies of liquid ammonia leakage accidents, so as to improve the safety level of liquid ammonia during storage. [ABSTRACT FROM AUTHOR]

Due to the ubiquity and importance of water, water dimer has been intensively studied. Computing the (ro-)vibrational spectrum of water dimer is challenging. The potential has eight wells separated by low barriers, which makes harmonic approximations of limited utility. A variational approach is imperative, but difficult because there are 12 coupled vibrational coordinates. In this paper, we use a product contracted basis whose functions are products of intramolecular and intermolecular functions computed using an iterative eigensolver. An intermediate matrix F facilitates calculating matrix elements. Using F, it is possible to do calculations on a general potential without storing the potential on the full quadrature grid. We find that surprisingly many intermolecular functions are required. This is due to the importance of coupling between inter- and intra-molecular coordinates. The full G16 symmetry of water dimer is exploited. We calculate, for the first time, monomer excited stretch states and compare P(1) transition frequencies with their experimental counterparts. We also compare with experimental vibrational shifts and tunneling splittings. Surprisingly, we find that the largest tunneling splitting, which does not involve the interchange of the two monomers, is smaller in the asymmetric stretch excited state than in the ground state. Differences between levels we compute and those obtained with a [6+6]D adiabatic approximation [Leforestier et al. J. Chem. Phys. 137 014305 (2012)] are ∼ 0.6 cm−1 for states without monomer excitation, ∼ 4 cm−1 for monomer excited bend states, and as large as ∼ 10 cm−1 for monomer excited stretch states. [ABSTRACT FROM AUTHOR]

In a methylammonium‐free (MA‐free) composition, the uncontrollable crystallization process between Cs and formamidine (FA) currently hinders its efficiency enhancement, especially in inverted perovskite solar cells (PSCs). Here, a dual‐interface modification of perovskite films is proposed by simultaneously introducing additives and surface passivators. In particular, (aminomethyl)phosphonic acid (AMP) is introduced into the precursor solution to balance crystallization by inducing the preferential crystallization of FA through the specific formation of strong hydrogen bonds with FA. In addition, AMP spontaneously sinks and anchors to the buried interface to fill the voids of the self‐assembled monolayer (SAM) via the covalent bonds formed by ─PO3H2 and FTO. Subsequently, by the sequential modification of perovskite surface with 2‐(3‐fluorophenyl)ethylamine iodide (mF‐PEAI) and piperazine diiodide (PDI), a uniform surface potential is achieved and recombination losses at the interface are minimized. Notably, the dual‐interface‐modified inverted MA‐free PSCs achieve a state‐of‐the‐art power conversion efficiency (PCE) of 25.35% (certified: 24.87%) with a satisfactory Voc of 1.17 V based on the bandgap of 1.52 eV. Importantly, the unencapsulated devices maintain 92.8% and 91.7% of the initial efficiency after 1000 h of maximum power output (MPP) tracking and >800 h of heating at 85 °C, respectively, confirming excellent operational and thermal stability. [ABSTRACT FROM AUTHOR]

Photothermal synergistic catalysis (PTSC) offers promising potential for the dry reforming of methane (DRM) to produce syngas, but designing suitable catalysts suitable for photothermal processes poses significant challenges. In this study, we present a core-shell catalyst consisting of a SiO2 shell encapsulating Ni loaded on the CeO2–ZrO 2 support, which proved to be well-suited for PTSC-DRM under milder conditions. Compared to traditional thermal catalysis (TC), PTSC at 600 °C exhibited superior CH4/CO2 conversions (63.5 %/55.9 %) and higher H 2 /CO yields (137.0 mmol·g -1 ·h -1 /182.9 mmol·g -1 ·h -1). The TOFs under PTSC-DRM are 1.3–2.9 times higher than the corresponding TOFs in TC-DRM. The catalyst demonstrated strong stability during a 60-h aging test, which can be attributed to the restricted migration of Ni and the accelerated movement of oxygen induced by illumination via structure effect which also lead to the boosted activity benefited from a reduced bandgap of 2.2 eV and improved charge separation/migration efficiency during PTSC reaction. [Display omitted] • Boosted syngas production via photothermal synergistic dry reforming of CH 4. • A novel core-shell structured Ni/CeO 2 –ZrO 2 @SiO 2 catalyst tailored for photothermal synergistic reaction. • Enhanced activity and anti-carbon performance of the catalyst due to the encapsulation of SiO 2. [ABSTRACT FROM AUTHOR]

The biological concentration effect of radionuclides in marine fish has exacerbated public anxiety about seafood security in the context of Fukushima nuclear-contaminated water discharged into the ocean. However, the most polluted port near the Fukushima Daiichi Nuclear Power Plant (FDNPP) has seldom been investigated, especially for radioactivity in marine fish. In this study, decadal observations of radiocesium in marine fish and seawater from the most polluted port were simultaneously established after the Fukushima Nuclear Accident. We found a generally decreasing trend of historical 137Cs activity in seawater, with seasonal variations modulated by precipitation. Seasonal variations were elucidated with finer detail and divided into exponential decline in the dry season and steady variation in the wet season. A novel method was proposed to estimate the continuing source term of 137Cs derived from the FDNPP, which was 3.9 PBq in 2011 and 19.3 TBq between 2012 and 2022 on the basis of historical 137Cs. The biological concentration effect of marine fish is quantitatively emphasized according to the higher ratio of overstandards for radiocesium in marine fish relative to that in seawater. Long-term observation and analysis of radiocesium in marine fish and seawater from the most polluted port would provide insights into the scientific evaluation of the effectiveness of the decommissioning of the FDNPP in the past and share lessons on the fate of Fukushima-derived radionuclides in the future. [ABSTRACT FROM AUTHOR]

Cesium removal from aqueous solutions of radioactive waste streams is a challenge in the field of radioactive waste management; this is due to the small atomic radii of Cs+ metal ions and their high migration ability. So, the development of a withstand system for the removal of Cs+ is crucial. In the current study, the removal of radioactive cesium from aqueous solutions using an RO-TLC membrane was studied. Two modifications were conducted; the first is to enlarge the cesium metal ion radii by interacting with mono- and dibasic acids, namely, stearic acid, tartaric acid, citric acid, and EDTA, and the second is the modification of the RO membrane pore size via reaction with the same acids. The modification was confirmed using SEM, FTIR, and EDX analysis techniques. The Cs+ and K+ rejection capacities and water permeability across the membrane at 1.5 bars were evaluated. Along with using the above-mentioned acids, the Cs+ metal ion retention index (RCs) was also obtained. It was found that employing EDTA as a chelating agent in an amount of 1.5 g/L in conjunction with the variation of feed content since it provided the highest value of RCs ~ 98% when used. Moreover, the elution of Cs+ using water, EDTA, ammonia, and HCl is also investigated. The optimal value of the eluent concentration was (0.25 M) HCl. Finally, Langmuir and Freundlich isotherm models were applied for a better understanding of the sorption process. The results of the present work more closely match the Langmuir isotherm model to determine the dominance of the chemical sorption mechanism. [ABSTRACT FROM AUTHOR]

As M310 series units, CPR1000 Nuclear Power Plant in China is also the first batch of demonstration nuclear power plants in China to try out SOP(the state-oriented procedure) accident procedures. The establishment of SOP accident regulations is an important work to mitigate the consequences of radioactive accidents in the design of nuclear power plants, and it is also the embodiment of the defense-in-depth requirements in the implementation of nuclear safety regulations. It can handle superimposed accidents, human errors in program implementation and events not considered in the primary cause sequence. In order to study the efficiency of its upgraded SOP procedure and its ability to deal with severe accidents, the typical primary cause event of severe accidents in nuclear power plants-such as the total loss of feedwater accident of steam generators has been adopted for research. The initial state of the simulation is the full power operation of the nuclear power plant, the simulation process is from the loss of all the water supply accidents to the whole accident processing. A total of 30 simulation experiments were carried out. The temperature and pressure of the key parameters obtained are the average values of 30 simulation experiments. The stability and efficiency of the updated SOP are evaluated by the treatment time of the water supply loss accident and the changes of reactor temperature and pressure after the accident. The results show that the upgraded SOP procedure is more stable and efficient. The upgraded SOP procedure, when dealing with other types of accidents, has improved the treatment of residual heat conduction in the core, increased the efficiency of accident treatment, and enhanced the safety of the reactor. At the same time, based on the weaknesses of the upgraded SOP procedure, constructive suggestions on changing the setting value of the steam generator bypass valve have also been put forward accordingly. Furthermore, it can be concluded from many simulated accidents that this change will win about 5% more of the disposal time for nuclear power plants under accidents, which provides references for the subsequent upgrading of M310 series power plant procedures. [ABSTRACT FROM AUTHOR]

The current work discusses the radiation attenuation capability and different shielding characteristics of different mortar samples. The samples were prepared by replacing different percentages of fine aggregate with iron filling and replacing different percentages of hydrated lime with Bi2O3 (0–50 wt.%). The prepared mortar samples are coded as CHBFX where X = 0, 10, 30, and 50 wt.%. The mass and linear attenuation coefficient was determined experimentally using a narrow beam technique, where a high purity germanium detector, and different point gamma-ray sources (such as Am-241, Cs-137, and Co-60). The linear attenuation coefficient was also calculated using the Monte-Carlo simulation code and the online Phy-X/PSD software. The comparison of the three methods showed a good agreement in the results. The linear attenuation coefficient drops from 19.821 to 0.053 cm−1 for CHBF0, from 27.496 to 0.057 cm−1 for CHBF10, from 42.351 to 0.064 cm−1 for CHBF30, and from 55.068 to 0.071 cm−1 for CHBF50 at photon energy range from 0.015 to 15 MeV. The half-value layer thickness, tenth-value layer thickness, and mean free path of the prepared mortar composites were also calculated photon energy ranged from 0.015 to 15 MeV. The fast neutron removal cross-section of the prepared CHBFX mortar samples have values of 0.096 cm−1, 0.098 cm−1, 0.103 cm−1, and 0.107 cm−1 for the mortar samples CHBF0, CHBF10, CHBF30, and CHBF50, respectively. The results showed that the mortar sample with the highest iron filing concentration, CHBF50, provides the best protection against gamma rays and fast neutrons which could be used in the nuclear and medical fields. [ABSTRACT FROM AUTHOR]

A serious risk that harms the safe use of water and affects aquatic ecosystems is water pollution. This occurs when the water's natural equilibrium is disrupted by an excessive amount of substances, both naturally occurring and as a byproduct of human activities, that have varied degrees of toxicity. Radiation from Cs isotopes, which are common components of radioactive waste and are known for their long half-lives (30 years), which are longer than the natural decay processes, is a major source of contamination. Adsorption is a commonly used technique for reducing this kind of contamination, and zeolite chabazite has been chosen as the best adsorbent for cesium in this particular situation. The purpose of this research is to investigate a composite material based on magnesium phosphate cement (MPC). Magnesium oxide (MgO), potassium dihydrogen phosphate (KH2PO4), and properly selected retarders are used to create the MPC. The optimal conditions for this composite material are investigated through the utilization of X-ray diffraction, scanning electron microscopy, BET surface area analysis, and atomic absorption spectroscopy. The principal aim is to enable innovations in the elimination of radioactive waste-contaminated water using effective cesium removal. The most promising results were obtained by using KH2PO4 as an acid, and MgO as a base, and aiming for an M/P ratio of two or four. Furthermore, we chose zeolite chabazite as a crucial component. The best adsorption abilities for Cs were found at Qads = 106.997 mg/g for S2 and Qads = 122.108 mg/g for S1. As a result, zeolite is an eco-friendly material that is a potential usage option, with many benefits, such as low prices, stability, and ease of regeneration and use. [ABSTRACT FROM AUTHOR]

The focus of this paper is to analyze the trends and locations of accidents in the Greater Melbourne Area (GMA) during a 15-year period (2006–2020). The places where accidents were most prevalent were discovered and the reasons which are contributing to the high accident rates in those areas are determined. Analyzing the patterns over time and variations in the frequency of accidents helped to identify areas that have improved or deteriorated in terms of road safety. A Tweedie model was developed to examine the intricate interaction between the accident frequency and its potential contributing factors such as socio-demographics, road transport infrastructure, and built environment. Ultimately, a clustering analysis was performed to elucidate the dispersion of road accident risk ratings among different local government areas (LGAs), offering useful insights into road safety initiatives and prioritization. • The study linked built environment to accidents with Twidee and Space-time Cube. • Accidents down overall (20 yrs), but hotspots move outward. • Melbourne suburbs form five risk clusters based on accident frequency. [ABSTRACT FROM AUTHOR]

Transfer factors of some naturally-occurring and artificial radionuclides from an agricultural soil to rhizobacteria-treated Sesbania grandiflora, a small leguminous tree, were studied. Two plant growth promoting rhizobacteria (PGPR) strains (SCR17 and PCE2) were used to carry out an agricultural experiment in pots in semi-arid region (Syria). The results showed the bacterial strain (SCR17) increased the transfer and accumulation of 238U and 40K in Sesbania grandiflora, while both bacterial strains showed no effect on the accumulation of 234Th, 226Ra, 210Po and 210Pb in the treated plants. The transfer factor of 137Cs from soil to rhizobacteria-treated Sesbania grandiflora was negligible. The values of the transfer factors of 234Th, 226Ra, 210Po and 40K were found to be within the global values, while the values of the transfer factors of 238U and 210Pb were found to be relatively higher. This study highlights the importance of using Phytoremediation by PGPR strains for radionuclides-contaminated soils. Therefore, this method is a promising technique for the restoration and rehabilitation of contaminated sites with radionuclides, as it is low cost, easy to apply, and environmentally friendly. [ABSTRACT FROM AUTHOR]

High-LET-type cell survival curves have been observed in cells that were allowed to incorporate 125I-UdR into their DNA. Incorporation of tritiated thymidine into the DNA of cells has also been shown to result in an increase in relative biological effectiveness in cell survival experiments, but the increase is smaller than observed after incorporation of 125I-UdR. These findings are explained in the literature by the overall complexity of the induced DNA damage resulting from energies of the ejected electron(s) during the decay of 3H and 125I. Chromosomal aberrations (CA) are defined as morphological or structural changes of one or more chromosomes, and can be induced by ionizing radiation. Whether the number of CA is associated with the linear energy transfer (LET) of the radiation and/or the actual complexity of the induced DNA double-strand breaks (DSB) remains elusive. In this study, we investigated whether DNA lesions induced at different cell cycle stages and by different radiation types [Auger-electrons (125I), β– particles (3H), or γ radiation (137Cs)] have an impact on the number of CA induced after induction of the same number of DSB as determined by the γ-H2AX foci assay. Cells were synchronized and pulse-labeled in S phase with low activities of 125I-UdR or tritiated thymidine. For decay accumulation, cells were cryopreserved either after pulse-labeling in S phase or after progression to G2/M or G1 phase. Experiments with γ irradiation (137Cs) were performed with synchronized and cryopreserved cells in S, G2/M or G1 phase. After thawing, a CA assay was performed. All experiments were performed after a similar number of DSB were induced. CA induction after 125I-UdR was incorporated was 2.9-fold and 1.7-fold greater compared to exposure to γ radiation and radiation from incorporated tritiated thymidine, respectively, when measured in G2/M cells. In addition, measurement of CA in G2/M cells after incorporation of 125I-UdR was 2.5-fold greater when compared to cells in G1 phase. In contrast, no differences were observed between the three radiation qualities with respect to exposure after cryopreservation in S or G1 phase. The data indicate that the 3D organization of replicated DNA in G2/M cells seems to be more sensitive to induction of more complex DNA lesions compared to the DNA architecture in S or G1 cells. Whether this is due to the DNA organization itself or differences in DNA repair capability remains unclear. [ABSTRACT FROM AUTHOR]

In recent years, the lead-free double perovskite Cs2AgBiBr6 has emerged as an appealing alternative to lead-based perovskites due to its nontoxicity and long-term stability. In this study, we employed methyl acetate as an antisolvent and prepared high-quality Cs2AgBiBr6 films by a facile one-step spin-coating method. The prepared films exhibited excellent crystallinity with densely packed crystal grains. The root mean square roughness and average roughness of the obtained Cs2AgBiBr6 perovskite films were 6.69 and 5.43 nm, respectively. Furthermore, the memory device based on the Cs2AgBiBr6 perovskite films exhibited uniform and repeatable bipolar resistive switching performance with an ON/OFF ratio of 15, an endurance of 80 cycles, and a retention time of 104 s. This work showcases a simple and convenient one-step spin-coating method for depositing high-quality Cs2AgBiBr6 thin films while highlighting their potential application in resistive switching memories based on lead-free double perovskites. [ABSTRACT FROM AUTHOR]

Several researches have been studied the diffusion coefficient (Da) of radionuclide in soil samples in varies location around the world; however, the effect of cations in groundwater as a medium of saturation for Cs-137 diffusion in soil and bentonite remains to be accomplished. Compacted soil and bentonite layers are utilized in the construction of radioactive waste disposal sites, which serve to prevent the release of Cs-137 from the repository to the unsaturated zone. The samples used were soil from the prospective disposal site in SP4—Serpong Nuclear Center (SNC) and bentonite taken from Santrijaya, Tasikmalaya. The diffusion coefficient (Da) is used as indicator of Cesium-137 diffusion in the samples. Experimental measurements were conducted on a diffusion column unit that varied in diffusion time and density conditions to determine diffusion coefficients. The samples were cut into slices and analyzed using Multichannel Analyzer (MCA) unit to measure Cs-137 radioactivity. The measurement results were then incorporated into Fick's Law equation to obtain the value of the diffusion coefficient (Da) of Cs-137 in soil and bentonite. The experimental results showed that the diffusion coefficients of samples with groundwater simulation are in the range of 10–12 m2 s−1 for the local soil and bentonite samples, respectively. Compare to the similar experiment that was conducted previously, the results indicated that the groundwater content could slightly impact the increase in the diffusion coefficient value of Cs-137. [ABSTRACT FROM AUTHOR]

The present study addresses transformation of physicochemical forms (species) of artificial radionuclides in bottom sediments (BS) of the Yenisei River after the shutdown of the reactors at the Mining-and-Chemical Combine (MCC) at Krasnoyarsk. The BS samples collected from the Yenisei at the MCC in 2018–2021 contained 60Co, 137Cs, 152Eu, 154Eu, 155Eu, and 241Am. The species of radionuclides were studied using sequential extraction procedure. Considerable proportions of 60Co (48–100%) and 137Cs (72–83%), which are still released to the Yenisei with controlled discharges, were irreversibly bound to BS mineral solids. The percentages of europium isotopes, which have not been released to the Yenisei as part of controlled discharges since 2013, were lower in the irreversibly bound fraction (4.6–9.3% of 152Eu), but their representation as relatively mobile species was more diverse compared to 60Co and 137Cs. Interestingly, some percentage of 152Eu (up to 15.5%) was retained in the most mobile, exchangeable, form. The species of 154Eu and 152Eu differed, which can be explained by dissimilar origins of these isotopes. Further research is needed to investigate the mechanisms of physicochemical transformation of radionuclides in BS that enable them to be present in mobile species over long time periods and mechanisms of immobilization of artificial radionuclides in the environment. [ABSTRACT FROM AUTHOR]

The release of cobalt‐60 and cesium‐137 in the environment is considered dangerous pollutants. In this concern, the present work deals with gamma radiation‐induced synthesis of novel polyaniline/CuWO4 (PANi/CWO) nanocomposite adsorbent and estimating its potential adsorption capacity for cobalt‐60 and cesium‐137 from aqueous solution. The crystallite size of pure CWO NPs and PANi/CWO nanocomposite is found in the nanoscale range. Also, SEM images and XRD results confirmed the successful preparation of PANi/CWO nanocomposite. Further, the elemental mapping images proved that all the investigated elements were homogeneously distributed over the PANi/CWO nanocomposite. Besides, the adsorption experiments were conducted separately to investigate the adsorption behavior of cobalt‐60 and cesium‐137 by PANi/CWO nanocomposite. Adsorption processes have also been performed, and numerous factors, including medium pH, contact time, initial metal ion concentration, and temperature, have been tested. Batch experiments were done to get the optimum conditions for removing cobalt‐60 and cesium‐137. Four kinetic models were investigated, indicating that the adsorption process of cobalt‐60 and cesium‐137 onto PANi/CWO nanocomposite is controlled by chemisorption and intra‐particle diffusion. Four equilibrium isotherm models were investigated, revealing that the adsorption process is a monolayer and multilayer process on a heterogeneous surface. The (∆Ho) value suggested that this study's removal of cesium and cobalt has an endothermic behavior, whereas the positive (∆So) value proved that the examined system is random. The effect of temperature was investigated, and the calculated thermodynamic parameters indicated that the removal of cobalt‐60 and cesium‐137 by PANi/CWO nanocomposite has an endothermic behavior. [ABSTRACT FROM AUTHOR]

A novel polyacrylic acid–ammonium phosphomolybdate (PAA–AMP) adsorbent capable of highly selective adsorption of Cs+ in robust acid solutions was developed. The effects of adsorbent dosage, pH, contact time, temperature, and competing ions on the Cs+ removal performance were investigated. The adsorbent rapid (30 min) selective adsorption of Cs+ in a wide pH (pH = 1–12) range, with little effect of competing ions on the adsorption, and a maximum adsorption capacity of 66.71 mg g−1. The adsorption data fitted well with pseudo-second-order kinetics and the Langmuir isotherm model, and adsorption mechanism is ion exchange between NH4+ and Cs+. [ABSTRACT FROM AUTHOR]

The vacancy-ordered quadruple perovskite Cs4CdBi2Cl12, as a newly-emerging lead-free perovskite system, has attracted great research interest due to its excellent stability and direct band gap. However, the poor luminescence performance limits its application in light-emitting diodes (LEDs) and other fields. Herein, for the first time, an Ag+ ion doping strategy was proposed to greatly improve the emission performance of Cs4CdBi2Cl12 synthesized by hydrothermal method. Density functional theory calculations combined with experimental results evidence that the weak orange emission from Cs4CdBi2Cl12 is attributed to the phonon scattering and energy level crossing due to the large lattice distortion under excited states. Fortunately, Ag+ ion doping breaks the intrinsic crystal field environment of Cs4CdBi2Cl12, suppresses the crossover between ground and excited states, and reduces the energy loss in the form of nonradiative recombination. At a critical doping amount of 0.8%, the emission intensity of Cs4CdBi2Cl12:Ag+ reaches the maximum, about eight times that of the pristine sample. Moreover, the doped Cs4CdBi2Cl12 still maintains excellent stability against heat, ultraviolet irradiation, and environmental oxygen/moisture. The above advantages make it possible for this material to be used as solid-state phosphors for white LEDs applications, and the Commission International de l'Eclairage color coordinates of (0.31, 0.34) and high color rendering index of 90.6 were achieved. More importantly, the white LED demonstrates remarkable operation stability in air ambient, showing almost no emission decay after a long working time for 48 h. We believe that this study puts forward an effective ion-doping strategy for emission enhancement of vacancy-ordered quadruple perovskite Cs4CdBi2Cl12, highlighting its great potential as efficient emitter compatible for practical applications. [ABSTRACT FROM AUTHOR]

In situ gamma-spectrometric measurements were performed at grasslands (45 plots) and forests (6 plots) in the vicinity of the Belarusian nuclear power plant in September–October 2019. The aim of the study was to evaluate the baseline level of ambient dose equivalent rates of gamma radiation from natural radionuclides and 137Cs in the period preceding the commissioning of the NPP. The study revealed more than a 2-fold variability in values of the total ambient dose equivalent rate: from 29 to 72 nSv/h. This spread can be explained by variability in the content of natural radionuclides in the environment and, accordingly, ambient dose equivalent rate. At forest sites, compared to grassland sites, the values of ambient dose equivalent rates of gamma radiation from natural radionuclides were statistically significantly lower. The contribution of gamma radiation from 137Cs to the total ambient dose equivalent rate was insignificant and averaged 3% for grasslands and 6% for forests. [ABSTRACT FROM AUTHOR]

The knowledge of radionuclides sorption behavior of various site-specific heterogeneous geosystems is essential for developing different clean-up strategies and predicting the radiological risks for long term. The present study is aimed at understanding the mineralogical and textural characteristics of natural shale rock (sampled from Kachchh Basin of Gujarat, India) and its correlation with cesium (Cs) sorption behavior. The modal mineralogical composition, textural attributes, petrophysical properties, surface functionalities and morphology of shale were evaluated. Clay minerals (smectite, kaolinite and illite) constitute more than 40% of the shale along with the major component- quartz. A comprehensive Cs batch sorption study performed at varying experimental parameters demonstrated that the maximum Cs retention of shale was 34.80 ± 2.85 mg g−1 in the studied concentration range. Sorption equilibrium data agreed well with Freundlich isotherm, highlighting the heterogeneity of shale. Variation in solution pH (in the range of 6–10) during sorption demonstrated the buffering of solution in near neutral range indicating the role of cations (available in the interlayers of clay minerals) in Cs uptake. Alternatively, the presence of illite mineral in the shale with known frayed edge sites contributed to the irreversibility of sorption event. The present studies illustrate the potential of shale as host rock for its application in nuclear waste management. [ABSTRACT FROM AUTHOR]

We present the R -band polarimetry of two low-latitude Lynd's clouds L1495 and L1498 acquired with AIMPOL at Aryabhatta Research Institute of Observational Sciences, Nainital, India. The estimated polarization across the regions of L1495 and L1498 is typically in the range of ∼1–5 per cent and the position angle is typically in the range of ∼100°–137° from which we infer the morphologies of the corresponding magnetic field in the envelope region (⁠|$\theta_{\rm B}^{\rm env}$|⁠). In both clouds, the magnetic fields are found to be aligned with the galactic field (θGP). Due to their close proximity to the galactic plane, we incorporate the values of offset (⁠|$\theta _{\rm off} = |\theta _{\rm B}^{\rm env} - \theta _{\rm GP}|$|⁠) from this study into our previously established geometrical correlation between the variation in relative orientation with the galactic longitude. We find that the offsets estimated for two clouds L1495 and L1498 in this investigation are consistent with the offsets predicted by our previous study. We also generate the extinction map for the two clouds using the NICE technique, and the extinction structure is found to be analogous to the dust structure at the denser region of the cloud as obtained from the 500 µm dust continuum emission maps of Herschel 1 SPIRE. Three distinct cores with high extinction are detected in L1495, and two such cores are also detected in L1498. We also estimate the mean particle density (⁠|$\lt n_{\rm H_2}\gt $|⁠) at the peripheral region as well as the high extinction cores of the clouds. [ABSTRACT FROM AUTHOR]

This study reviews the performance analysis of a 137Cs irradiation system that has recently been installed in the laboratory of Uzbek National Institute of Metrology. The laboratory is responsible for calibrating calibration facilities and for calibrating most protection level radiation monitoring instruments used in medical, nuclear, industrial and academic settings in Uzbekistan. This system employs the most advanced radiation safety standards, along with 21st century source automation methods. In this work, we review the system's performance according to ISO 4037 and present measurement uncertainty budget. Our analysis shows excellent results in terms of scattered radiation, beam uniformity and field size, change in source position, test for source impurities, chamber stability and source calibration, and all these parameters fully comply with the requirements of ISO 4037. [ABSTRACT FROM AUTHOR]

The construction of nuclear power plants necessitates careful consideration of the discharge and fixation of nuclear waste. Geopolymers are new cement-based materials (CBMs) with three-dimensional cage-like structures that enable effective nuclear waste fixation. In this work, the adsorption of radioactive caesium and strontium ions by sodium aluminosilicate hydrate (NASH) gel, the main component of geopolymers, was investigated using molecular dynamics simulations to obtain nanoscale insights into the ions' interactions with the gel. The formation of strong ion–oxygen bonds allowed both ions to be effectively adsorbed on the NASH surface, but the adsorption ratio of strontium ions (17.2%) was slightly lower than that of caesium ions (21.0%). Because strontium ions are divalent, they can form stronger electrostatic interactions with water molecules and chloride ions, which hinders their approach to the interface. For the same reason, the diffusion coefficient of strontium ions in solution is lower than that of caesium ions. These results provide new insights into the nuclear waste fixation capacity of NASH gel and guidance for the design of new CBMs for radioactive waste disposal. [ABSTRACT FROM AUTHOR]