Pyrochemical processing and molten-salt reactors have recently garnered significant attention as they are promising options for future nuclear technologies, such as those for recycling spent nuclear fuels and the next generation of nuclear reactors. Both of these technologies require the use of high-temperature molten salt. To implement these technologies, one must understand the electrochemical behavior of fission products in molten salts, lanthanides, and actinides. In this study, a rotating-disk-electrode (RDE) measurement system for high-temperature molten salts is constructed and tested by investigating the electrochemical reactions of Sm3+ in LiCl–KCl melts. The results show that the reduction of Sm3+ presents the Levich behavior in LiCl–KCl melts. Using the RDE system, not only is the diffusion-layer thickness of Sm3+ measured in high-temperature molten salts but also various electrochemical parameters for Sm3+ in LiCl–KCl melts, including the diffusion coefficient, Tafel slope, and exchange current density, are determined.

Alluvial beds are intimately associated with electrical properties related to soil types, including clay mineral content, porosity, and water content. The hydraulic property governs water movement and storage in alluvial beds. This study revealed electrical resistivity and hydraulic properties in space and time in relation to the hydrogeological data, groundwater pumping, and rainfall infiltration into the alluvial bed located in Daesan-myeon, Changwon City. An electrical resistivity survey with electrode spacings of 2 and 4m using a dipole-dipole array indicates that electrical resistivity changes in the alluvial bed depend on groundwater pumping and rainfall events. Additionally, rainfall infiltration varies with hydraulic conductivity in the shallow zone of the alluvial bed. The 2 m electrode spacing survey confirms that electrical resistivity values decrease at shallow depths, corresponding with rainfall and increased water content in the soil, indicating rainfall infiltration approximately 1-2 m below the land surface. The 4m electrode spacing survey reveals that hydraulic conductivity (K) values and electrical resistivity (ρ) values display an inverse relationship from the surface to the water table (approximately 9 m) and at deeper levels than the water table. Notably, ρ values are impacted by pumping around the depth of the water table at 9 m. This study suggests that time-lapsed electrical resistivity surveys in space and time could be effective tools for detecting the impact of rainfall and pumping, as well as hydraulic conductivity in shallow alluvial beds.

Black ice, a thin and nearly invisible ice layer on roads and pavements, poses a significant danger to drivers and pedestrians during winter due to its transparency. We propose an efficient black ice detection system and technique utilizing Global Positioning System (GPS)-reflected signals. This system consists of a GPS antenna and receiver configured to measure the power of GPS L1 band signal strength. The GPS receiver system was designed to measure the signal power of the Right-Handed Circular Polarization (RHCP) and Left-Handed Circular Polarization (LHCP) from direct and reflected signals using two GPS antennas. Field experiments for GPS LHCP and RHCP reflection measurements were conducted at two distinct sites. We present a Normalized Polarized Reflection Index (NPRI) as a methodological approach for determining the presence of black ice on road surfaces. The field experiments at both sites successfully detected black ice on asphalt roads, indicated by NPRI values greater than 0.1 for elevation angles between 45o and 55o. Our findings demonstrate the potential of the proposed GPS-based system as a cost-effective and scalable solution for large-scale black ice detection, significantly enhancing road safety in cold climates. The scientific significance of this study lies in its novel application of GPS reflection signals for environmental monitoring, offering a new approach that can be integrated into existing GPS infrastructure to detect widespread black ice in real-time.

This study proposes a soil moisture retrieval method from ground reflection signals received by Global Positioning System (GPS) antenna modules consisting of an up-looking (UP) right-hand circular polarization (RHCP) and two down-looking (DW) RHCP and left-hand circular polarization (LHCP) signals. Field experiments at four different surface types (asphalt, grassland, dry soil, and moist soil) revealed that the DW RHCP and LHCP signals are affected by antenna height and multipath interference signals. The strength differences between the DW LHCP and UP RHCP signals were in good agreement with the DW LHCP signals. Methodologically, this study applied a spectrum analysis to the detrended surface-reflected signals for RHCP and LHCP. The study indicated that the down-looking antenna exhibited greater sensitivity to reflected GPS signals than the up-looking antenna. We demonstrated the feasibility of estimating soil moisture using GPS signals, by comparing LHCP signals received by the down-looking antenna with theoretical values. This study presents a novel method for estimating soil moisture in vegetated areas, leveraging the advantage of crosspolarization comparisons to achieve stronger signal strength than single-polarization reflection signals. With further research, including long-term observations and detailed analysis, the proposed method has the potential to enhance performance significantly.

Today, the principles of green chemistry are being fundamentally applied in the chemical industry, such as the nitrobenzene industry, which is an essential intermediate for various commercial products. Research on the application of response surface methodology (RSM) to optimize nitrobenzene synthesis was conducted using a sulfated silica (SO4/SiO2) catalyst and batch microwave reactor. The nitrobenzene synthesis process was carried out according to RSM using a central composite design (CCD) design for three independent variables, consisting of sulfuric acid concentration on the silica (%), stirring time (min), and reaction temperature (°C), and the response variable of nitrobenzene yield (%). The results showed that a three-factorial design using the response surface method could determine the optimum conditions for obtaining nitrobenzene products in a batch microwave reactor. The optimum condition for a nitrobenzene yield of 63.38 % can be obtained at a sulfuric acid concentration on the silica of 91.20 %, stirring time of 140.45 min, and reaction temperature of 58.14 °C. From the 20 experiments conducted, the SO4/SiO2 catalyst showed a selectivity of 100 %, which means that this solid acid catalyst can potentially work well in converting benzene to nitrobenzene.

Caprine cryptosporidiosis mainly occurs in young goats, with morbidity rates of 80%–100% and mortality over 50% in goat kids. However, limited research has been conducted on the impact of Cryptosporidium parvum, a diarrhea-causing pathogen, on the intestinal microbiota of goat kids. In this study, 16S rRNA-based metataxonomic analysis was performed to compare the microbial diversity and abundance of the gut microbiota between C. parvum-infected and uninfected goat kids. In total, 12 goat fecal samples were collected, including seven naturally C. parvum-infected and five uninfected goats from Chungcheongbuk-do, Korea. After amplification of the V3–V4 hypervariable region of the bacterial 16S rRNA, high-throughput sequencing was performed. The results showed differences in the microbial composition between C. parvum-infected and uninfected groups based on beta diversity. Firmicutes and Bacteroidetes were the most dominant phyla in both groups. However, no significant difference was observed in the Bacteroidetes/Firmicutes ratio between the two groups. Compared with the uninfected group, the C. parvum-infected group showed significantly higher abundances of Tyzzerella nexillis, Lactobacillus johnsonii, Butyricicoccus pullicaecorum, Enterococcus raffinosus, Enterococcus faecalis, and Negativicoccus massiliensis, and significantly reduced abundances of Aerococcus vaginalis, Faecalicoccus pleomorphus, Oribacterium parvum, and Coprococcus comes. These findings indicate that C. parvum infection, which is associated with diarrhea in neonatal goats, induces alterations in the caprine gut microbiota.