Thermal cutting processes that can be applied to dismantling nuclear power plants include oxygen cutting, plasma cutting, and laser cutting. According to the global trend, research projects are being carried out in various countries to upgrade laser cutting, and many studies are also being conducted in Korea with plans to apply laser cutting processes when dismantling nuclear power plants. However, with the current technology level of the laser cutting process, the maximum thickness that can be cut is limited to 250 mm. Therefore, in this study, a laser-oxygen hybrid cutting process was implemented by adding a laser heat source to the oxygen cutting process that can cut carbon steel with a thickness of 250 mm or more (RV, beam, column, beam, etc.) when dismantling the nuclear power plant. This has the advantage of improving the cutting speed and reducing the cutting width Kerf compared to conventional oxygen cutting. In this research, the laser-oxygen hybrid cutting process consisted of laser cutting to which Raycus’ 8 kW Fiber Laser power source was applied and oxygen cutting to which hydrogen was applied with Fuel Gas. The oxygen torch was placed perpendicular to the test piece, and the laser head was irradiated by tilting 35° to 70°. The effects of cutting directions on quality and performance were studied, and cutting paths were selected by comparing cutting results. Thereafter, it was confirmed that there is an optimal laser output power according to the cutting thickness by studying the effect on the cutting surface quality by changing only the laser output power under the same cutting conditions. The results of this study are expected to be helpful in the remote cutting process using laser-oxygen hybrid cutting when dismantling domestic nuclear power plants in the future.

In KNF, fuel performance analysis modules were developed to predict the overall behavior of a fuel rod under normal operating conditions. Their main focus is to provide information on initial conditions prior to dry storage. Potential degradation mechanisms that may affect sheath integrity of spent CANDU fuel during dry storage are: creep rupture under internal gas pressure, sheath oxidation in air environment, stress corrosion cracking, delayed hydride cracking, and sheath splitting due to UO2 oxidation for a defective fuel. To upgrade the developed modules that address all the damage mechanisms, the first step was a review of the available technical information on phenomena relevant to fuel integrity. The second step was an examination of the technical bases of all modules, identify and extend the ranges of all modules to required operating ranges. The 300°C spent CANDU fuel sheath temperature metric for dry storage ensures spent CANDU fuel element integrity from the failure mechanisms of creep rupture, oxidation and stress corrosion cracking at a failure probability of 2×10-5 for a dry storage time of 100 years. The 300°C sheath temperature metric for dry storage has relatively a lower failure rate than the target criteria for dry storage of spent LWR fuel. Although different modes of failure were treated separately for simplicity, ignoring possible synergistic effects, these results are conservative because of the conservative assumptions that have been made for evaluating spent fuel element conditions, and because of the inherent conservatism of the applied models. Additional conservatism of the model comes from the fact that isothermal conditions do not prevail in actual storage conditions. Further R&D being considered includes acquisition of new functional models to implement overall fuel behavior evaluation and cover spent CANDU fuel in dry storage, and upgrades of the analysis module to achieve sufficient accuracy in key output parameters. The developed modules provide a platform for research and industrial applications, including the design of fuel behavior experiments and prediction of safe operating margins for spent CANDU fuel.

Drosophila suzukii (Diptera, Drosophilidae) can damage thin-skinned fruits (plums, cherries, peaches, blueberries, and strawberries) by laying eggs inside the fruit. In this study, a basic experiment was conducted to investigate the preference of D. suzukii to export table grape varieties. Four varieties of grapes (Kyoho grape, Shine muscat, Campbell grape, and Black sapphire) were placed in a cage containing more than 2,500 number of D. suzukii adults for 6, 8, 10, 12, and 24 hours and the egg-laying in grape has been induced. After 2 weeks, the number of pupae that emerged was counted. As a result, the largest number of pupae was generated in Kyoho grape among the four types of grapes, indicating that D. suzukii prefers to lay egg in Kyoho grape. Through this experiment, it was determined that 6 h was the appropriate inoculation time, and then an inoculation experiment was conducted on Kyoho grape. The total weight of the Kyoho grape used in the experiment was 36.119 kg, and a total of 2594 pupae were generated. The average number of D. suzukii per cluster was about 50. All stages of D. suzukii treated with low temperature(1℃) for 10 days were completely controlled.

Phosphine is a common pesticide used to control grain pests in Rice Processing Complex(RPC). However, increasing use of aluminum phosphide caused the occurrence of phosphine resistance pests. In this study, phosphine resistance pests collected at RPC in 2023 was investigated with FAO No. 16 test, Dihydrolipomaide dehydrogenase(DLD) test and amino acid mutation analysis to identify the occurrence of phosphine resistance in Korea. Tested pests were collected in the 7 province 35 region. As a result of the FAO test of 21 regions, all sample were phosphine sensitives. In DLD test and amino acid analysis, 7 region samples were weak resistances. It is required to inspect the RPC and other grain storage continuously to inhibit the widespread of resistant pest.

Collagen peptides have garnered significant attention as functional foods across multiple fields due to their capacity to regulate physiological and hormonal processes, offering numerous advantages. However, despite their broad range of applications, comprehensive research on the potential toxicity of these substances remains lacking. Therefore, this study sought to assess the acute oral toxicity of a collagen peptide derived from skate (Raja kenojei) skin (CPSS) in both rats and dogs. In the rat model, CPSS was orally administered at doses of 300 and 2,000 mg/kg to Sprague-Dawley rats. An escalating single-dose oral toxicity assessment at doses of 500, 1,000, and 2,000 mg/kg was carried out in beagle dogs with 3-day intervals between doses. Throughout the 14-day post-administration assessment period, clinical signs, mortality rates, changes in body weight, and necropsy observations were closely monitored. After oral administration, no signs of toxicity associated with CPSS were observed in either rats or dogs. Therefore, the oral LD50 (approximate lethal dose for 50% mortality) for CPSS in rats was determined to exceed 5,000 mg/kg, and the maximum tolerated dose for dogs was estimated to be above 2,000 mg/kg. Consequently, this study offers safety data on the use of CPSS in functional foods and medicinal applications.

Prior studies have focused primarily on the issue of consumers’ privacy concerns in personalized advertising, but little is known about the effect of transparency awareness using data collection notifications on consumers. This study focuses on the relationship between consumers’ perceptions of the AI algorithms underlying online behavioral advertising (OBA) and the advertising effects. Our research model indicates that displaying data collection notifications regarding OBA and personalized ads increases favorable perceptions of AI systems, such as transparency. Moreover, the model suggests that personalized ads induce higher perceived surveillance than non-personalized ads.

The prolonged and heavy East Asian summer precipitation in 2020 may have been caused by an enhanced Madden-Julian Oscillation (MJO), which requires evaluation using forecast models. We examined the performance of GloSea6, an operational forecast model, in predicting the East Asian summer precipitation during July 2020, and investigated the role of MJO in the extreme rainfall event. Two experiments, CON and EXP, were conducted using different convection schemes, 6A and 5A, respectively to simulate various aspects of MJO. The EXP runs yielded stronger forecasts of East Asian precipitation for July 2020 than the CON runs, probably due to the prominent MJO realization in the former experiment. The stronger MJO created stronger moist southerly winds associated with the western North Pacific subtropical high, which led to increased precipitation. The strengthening of the MJO was found to improve the prediction accuracy of East Asian summer precipitation. However, it is important to note that this study does not discuss the impact of changes in the convection scheme on the modulation of MJO. Further research is needed to understand other factors that could strengthen the MJO and improve the forecast.

Patients experiencing out-of-hospital cardiac arrest (OOHCA) during the weekend are less likely to survive to hospital admission than those experiencing OOHCA on weekdays. We aimed to determine whether the survival rates of in-hospital cardiac arrest (IHCA) were lower on weekends than on weekdays. We comprehensively reviewed the records of patients who experienced IHCA at CBNUH between 2018 and 2020. A total of 861 IHCAs occurred during the study period; these data included recurrent IHCA cases, as some patients experienced more than one IHCA. Of these, 739 IHCA cases were included in the survival analysis, and the survival rate was 65.2%, which is higher than the rate reported in a previous study. There were no differences in the survival rate between weekdays and weekends. Additionally, the time of day at which IHCA occurred and pre-IHCA intubation status did not affect survival. Patients in wards were less likely to survive than those in intensive care units (60.0% vs. 66.0%). Although pre-IHCA intubation did not show any added value in preventing sudden cardiac arrests, meticulous patient care and monitoring in terms of intra- or extrapulmonary oxygen therapy is needed, as is the promotion of cardio-pulmonary-cerebral resuscitation (CPCR) equipment availability and quick rescuer responses for patients with IHCA. Our findings may be of value in improving CPCR guidelines and monitoring patients at risk of IHCA.

The operation of nuclear power plants, nuclear waste depositories, and the decontamination and decommissioning of nuclear power plants all have the possibility of generating various kinds of radionuclides that can be formed as gaseous or liquid phases. Among the radionuclides, strontium is considered as most harmful substance due to its abundance in nuclear accident effluent, long half-life, high fission yield, high water solubility, and high mobility in aquatic environment. To remove strontium from aquatic environment, adsorption technique is mainly used with high economic feasibility, efficiency, and selectivity. Previously, we synthesized sodium titanates with mid-temperature hydrothermal method as selective strontium adsorbent in aqueous solution. Moreover, it was demonstrated that synthesized sodium titanates show high strontium adsorption rate with high selectivity with high surface area, pore diameter and volume. Herein, we investigated the surface structure of synthesized sodium titanates before and after strontium adsorption in aqueous solution using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analysis. According to SEM and EDS experimental results, aquatic strontium can be adsorbed as surface precipitation with formation of cube-shaped structure, which is quite similar strontium titanate structure crystals onto the surface of sodium titanates. In addition, XPS experimental results revealed that the titanium ions on the surface of sodium titanates were oxidized during strontium surface precipitation process, and the sodium ion on the surface of sodium titanates were exchanged with aquatic strontium ions via ion exchange process during strontium adsorption process.

In the event of a radioactive release, it is essential to quickly detect and locate the source of the release, as well as track the movement of the plume to assess the potential impact on public health and safety. Fixed monitoring posts are limited in their ability to provide a complete picture of the radiation distribution, and the information they provide may not be available in real-time. This is why other types of monitoring systems, such as mobile monitoring, aerial monitoring, and personal dosimeters, are also used in emergency situations to complement the information provided by fixed monitoring posts. Also, the monitoring system can be improved by using the Kriging technique, which is one of the interpolation methods, to predict the radiation dose in the relevant districts. This can be achieved by utilizing both the GPS information and the radiation dose measured at a particular point. The Kriging method involves estimating the value between different measurement points by considering the distance between them. The model used GPS and radiation data that were measured around the Hanbit NPP. The data were collected using a radiation measuring detector on a bus that traveled around the NPP area at 2-second intervals for one day. From the collected data, 200 data points were randomly selected for analysis, excluding the data measured at the bus garage out of a total of 16,550 data points. The average dose of the daily measurement data was 117.94 nSv/h, and the average dose of the 200 randomly extracted data was 119.17 nSv/h. The GPS and radiation dose data were utilized to predict the radiation dose around the Yeonggwang area where the Hanbit NPP is located. In the event of an abnormal release of radioactive material, it can be difficult to accurately determine the dose unless a monitoring measurement point is present. This can delay the rapid evacuation of residents during an emergency situation. By utilizing the Kriging model to make predictions, it is anticipated that more accurate dose predictions can be generated, particularly during accident scenarios. This can aid in the development of appropriate resident protection measures.