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국내 폭염-가뭄 복합 재해 발생 증가에 따른 기후 리스크 평가의 필요성
No full textIn recent years, the frequency of compound drought-heatwave events (CDHEs) has increased significantly. Previous studies have shown that CDHEs have a greater impact on society and ecosystems than individual hazards. Therefore, it is necessary to assess climate risk of CDHEs. However, few studies have investigated the current status of CDHEs in Republic of Korea and conducted related risk assessments. In this study, we used the MYRIAD-Hazard Event Sets Algorithm (MYRIAD-HESA), which generates multi-hazard pairs using daily heatwave and drought data, to analyze the occurrence of CDHEs during the May-October period from 1979 to 2023. The results were then used to assess climate risks in the health and agricultural sectors across the country's 17 administrative districts. The analysis revealed an increasing trend in the number of CDHEs in recent years, with an average duration of about 11.4 days. The districts most affected by CDHEs were Seoul, Gyeonggi-do, Gyeongsang-do, and Jeollanam-do, which experienced a higher hazard intensity than a single heatwave or drought. The risk assessment identified Gyeonggi-do as having a 'very high' risk of CDHEs in the health sector, while Jeollanam-do and Gyeongsangbuk-do, both major rice-producing regions, had the same risk in agricultural sector. In particular, when risk assessments focused only on individual hazards without considering CDHEs, the risk was found to be underestimated in Gyeongsangnam-do and tance of further research into the occurrence of compound hazards such as CDHEs, and underscores the need for climate risk assessments targeting these events.N
Edge-Plane-Selective Formation of Mn Vacancies in β-Na<sub>0.7</sub>MnO<sub>2+<i>y</i> </sub> for Air-Stable Cathode Materials in Sodium-Ion Batteries
No full textManganese-based P2-type Na x MnO2+y , particularly beta-Na0.7MnO2+y , exhibit high reversible capacity but are prone to stability issues, especially hydration-induced degradation when exposed to air. Herein, a significant improvement in the air stability of beta-Na0.7MnO2+y cathodes is achieved through a selective transition of their edge planes to alpha-Na0.7MnO2+z . When beta-Na0.7MnO2+y particles are oxidized at a relatively low temperature (350 degrees C), oxygen is selectively inserted at the edge planes due to the higher energy barrier for oxygen insertion at the basal planes compared with the edge planes. This mild oxidation selectively locally creates manganese vacancies near the edge plane surface, promoting the exclusive formation of alpha-Na0.7MnO2+z on the edge surface. The alpha-Na0.7MnO2+z nanolayers on the edge planes effectively suppress H2O insertion during air exposure, eventually mitigating the phase transition of beta-Na0.7MnO2+y to Na gamma MnO2<middle dot>delta H2O birnessite during storage. Moreover, this plane-selective formation of alpha-Na0.7MnO2+z enhances the electrochemical performance of beta-Na0.7MnO2+y , such as stable capacity retention.N
All Weather-Usable Wearable Dual Energy Harvester for Outdoor Sustainable Operation
No full textSustainable power sources for outdoor wearable electronics are essential for the continuous operation of wearable devices. However, the current lack of engineering design that can harvest energy regardless of weather conditions presents a significant challenge. In this regard, this study introduces a wearable, breathable all-weather usable dual energy harvester (AWuDEH) that can seamlessly generate electrical energy regardless of weather conditions. In this study, the AWuDEH integrated with the thermoelectric generator and the droplet-based electricity generator is demonstrated. The AWuDEH, especially engineered with a bi-functional top substrate for radiative cooling and electrification, achieves sustainable energy harvesting outdoors, thereby addressing the conventional challenge associated with the necessity for separate energy harvesters tailored to outdoor usage contingent on weather conditions. The device reaches a maximum power output of 14.6 mu W cm-2 under simulated sunny conditions and generates a much more enhanced thermoelectric power of 74.78 mu W cm-2 and a droplet-based electric power of 256.25 mW m-2 in rainy conditions. As proof, this study developed self-powered wearable electronics capable of acquiring physiological signals in simulated outdoor scenarios. This study presents a promising advancement in wearable technology, offering a potent solution for sustainable energy harvesting independent of weather conditions.Y
Effects of Temperature on the Microbial Growth and Quality of Unsealed Dry Pet Food during Storage
No full textDry pet food is a convenient option for pet owners, but its storage conditions can impact its microbial growth and quality. In this study, we examined the effects of storage temperature on the quality and microbial growth of dry pet food. The pet food was stored at 25 degrees C and 35 degrees C, respectively, and samples were analyzed on days 0, 30, 90, and 120 for microbial growth and quality attributes such as pH, color, lipid oxidation, and volatile basic nitrogen. While no initial microbial growth was observed due to the low water content and water activity, quality attributes showed changes over time. However, the changes were negligible, indicating that dry pet food remains feedable for up to 120 days even at a storage temperature of 35 degrees C. These findings suggest that dry pet food can be safely stored at room temperature or up to 35 degrees C without compromising its quality.Y
Identifying Fixed-effects Models with Heterogeneous Coefficients
No full textThis review provides an introduction to identification and
estimation methods for fixed-effects models with heterogeneous
coefficients, which require identification strategies that are notably
different from those for standard fixed-effects models. The strategies
imply consistent estimation methods for the parameters of interest,
which are also different from those used in standard fixed-effects
models. As an introductory review, this work defers detailed
implementation procedures for the estimation methods to future
studies
Upcycling and recycling of spent battery waste for a sustainable future: Progress and perspectives
No full textThe urgency of addressing the environmental and resource challenges posed by spent lithium-ion batteries (LIBs) has led to significant advancements in recycling and upcycling methodologies. This work aims to provide a comprehensive understanding of the progress made for LIB recycling and upcycling, offering perspectives for achieving a circular economy in battery technology. The review examines the latest innovations in LIB material recovery, focusing on both conventional recycling techniques and emerging upcycling strategies. It explores the motivation and importance of recycling spent LIBs, showing the critical need for sustainable solutions. A comprehensive overview of LIB recycling methodologies is provided, including pretreatment, preprocessing, pyrometallurgical, hydrometallurgical, bioleaching, direct recovery processes, electrochemical processes, and deep eutectic solvents. Emphasis is placed on the advanced upcycling of the cathode, anode, and separator materials, exploring composition/crystallisation engineering and structural modifications, including doping and surface coating. Furthermore, upcycling spent LIB materials into high-value products like catalysts and graphene is explored. The environmental impact, legislative landscape, and socioeconomic implications of battery recycling are critically analysed, with life cycle assessments underscoring the ecological benefits of these processes. Global perspectives on battery recycling practices are also examined, considering the varied approaches across different regions. Additionally, integrating artificial intelligence and the internet of things in optimising battery recycling is explored, demonstrating their potential to enhance efficiency and sustainability. The review concludes by identifying current challenges and proposing recommendations for future research and policy development.Y
Enhancing sediment toxicity assessments: Integrating bioavailability metrics with sediment effect concentrations for improved predictive accuracy
No full textSediments act as both sinks and sources for contaminants, particularly heavy metals like cadmium (Cd), posing risks to aquatic ecosystems. To evaluate sediment toxicity, sediment quality guidelines (SQGs) such as Sediment Effect Concentrations (SECs) have been widely applied. However, these methods often fail to resolve toxicity in the "Uncertain" range, where contaminant concentrations approach threshold values. This limitation arises from the reliance on bulk sediment concentrations, which do not account for bioavailability. This study integrates bioavailability-focused evaluation using Interstitial Water Toxic Units (IWTU) with traditional SEC frameworks to enhance sediment toxicity assessments. Using SECs alone, the toxicity thresholds were 0.09 mg/kg for longterm ecological safety (Consensus Level 1) and 0.36 mg/kg for benthic communities (Consensus Level 2). However, predictability, defined as the ability to correctly classify sediments correctly based on bioassay results, was limited to 43 % due to ambiguity in the "grey area" between these thresholds. To address this, aqueous phase Cd concentrations, derived from a partitioning coefficient model, were normalized to the USEPA Final Chronic Value (FCV) of 0.72 mu g/L to calculate IWTU values. This tiered approach integrates SECs with bioavailabilityfocused assessments, improving predictability to 76 % by refining classifications in the "Uncertain" category. The proposed framework effectively combines the ecological breadth of SECs with the precision of IWTU, addressing the limitations of single-method approaches. These findings underscore the importance of bioavailability-focused metrics in enhancing the reliability of sediment toxicity assessments and management practices.N
Examining the role of self-conscious emotions and perfectionistic self-presentation in workplace bullying among Korean nurses: a cross-sectional study
No full textBackgroundThere is a lack of systematic evaluations of the diversity and effectiveness of interventions to prevent workplace bullying. This cross-sectional study aimed to investigate the relationships among self-conscious emotions, perfectionistic self-presentation, and workplace bullying, focusing on both victim and perpetrator roles among nurses in South Korea.MethodsData from 522 nurses working in tertiary hospitals in South Korea were analyzed. Self-conscious emotions, perfectionistic self-presentation, and workplace bullying were assessed using the Test of Self-conscious Affect version 3 Short, the Perfectionistic Self-Presentation and Psychological Distress Scale, the Negative Acts Questionnaire-Revised, and the Negative Acts Questionnaire-Revised-Perpetrator.ResultsAmong victims, shame-proneness was the most significant factor, followed by anti-bullying training, subjective health status, externalization, current working unit, and total years of experience. Among perpetrators, shame-proneness was also the most significant factor, followed by guilt-proneness, anti-bullying training, externalization, perfectionistic self-presentation, current working unit, detachment/unconcern, subjective health status, and religion.ConclusionsWhile the influencing factors differed between victims and perpetrators, self-conscious emotions and perfectionistic self-presentation were key contributors to workplace bullying. Understanding these factors can support the development of interventions to prevent workplace bullying from both victim and perpetrator aspects. Trait-focused interventions, such as enhancing shame resilience, may help nurses manage aggressive behaviors, thereby reducing workplace bullying. Recognizing personality traits, including self-conscious emotions and perfectionistic self-presentation, may help nurses better understand their own and others' behaviors in the workplace. Nurse managers and administrators should consider these traits when addressing conflicts among nurses.Clinical trial numberNot applicable.Y
The Commitment Costs of Extended Deterrence and US Public Support for South Koreas Nuclear Development: Survey Experiments from South Carolina
No full textThis study examines the alliance dilemma in the US-South Korea relationship, characterized as a patron state fearing entrapment and a client state fearing abandonment. We argue that a patrons support for allied nuclearization is determined by the costs of extended deterrence and the clients independent nuclear capabilities. We predict that a patron favors gradually withdrawing extended deterrence if the costs are high and the client lacks an independent nuclear deterrent. Two survey experiments with South Carolina voters support this hypothesis. Study 1 found that higher extended deterrence costs increased support for South Koreas nuclearization without affecting support for the US immediate withdrawal of extended deterrence, while Study 2 showed increased support when respondents were informed of direct US security threats