Advanced Air Mobility (AAM) systems require efficient ground infrastructures to support high-frequency operations, where battery swapping stations play a critical role. In such environments, energy supply stability significantly affects system performance, particularly under time-varying demand. This study analyzes the impact of different energy supply configurations on battery swapping station performance using a simulation-based approach. Three configurations are considered: external power grid, distributed energy resources (DER), and integrated DER with energy storage systems (ESS). Key performance metrics include average waiting time, system staying time, task completion rate, and battery availability. The results show that grid-based systems experience increased delays under peak demand, while DER-only configurations improve some performance indicators, but their effectiveness remains limited under highly time varying demand due to supply variability. In contrast, the integration of DER and ESS achieves the most stable performance by mitigating energy fluctuations. These findings indicate that the temporal adaptability of energy supply is a critical factor in determining operational performance, highlighting the importance of integrating energy storage systems in AAM infrastructure design.

Advanced Air Mobility (AAM) systems rely on high-frequency operations of electric vertical take-off and landing (eVTOL) aircraft, making the performance of ground energy infrastructure a critical factor for overall system efficiency and reliability. In particular, battery swapping stations function as service systems in which multiple aircraft arrivals share limited resources, inevitably leading to processing delays under stochastic demand conditions. Previous studies have primarily focused on optimization-based scheduling and simulation-driven performance evaluation. However, the probabilistic mechanisms governing delay generation and operational stability in battery swapping systems have not been sufficiently explored. This study presents a probabilistic operational analysis of battery swapping stations in AAM using queueing theory. The system is modeled as a multi-server queueing system with stochastic arrival and service processes, and key performance metrics—including system utilization, average waiting time, and delay probability are analytically derived. Furthermore, delay behavior is examined not only in terms of average values but also through probabilistic distributions and service-level-based performance criteria. To validate the proposed analytical framework, MATLAB-based discrete-event simulations are conducted under various operational scenarios, including different arrival rates and service time variability conditions. The results indicate that stochastic characteristics significantly influence delay behavior and system stability, particularly under peak demand conditions. The proposed approach provides a theoretical foundation for understanding delay dynamics in AAM battery swapping operations and offers practical insights for designing stable and efficient ground infrastructure systems.

Purpose: This study aimed to evaluate the effects of a simulation-based cardiopulmonary resuscitation (CPR) education program on CPR knowledge, CPR attitude, and CPR performance confidence among new nurses. Methods: A one-group pre-test-post-test design was used. The participants were 33 new nurses from a tertiary hospital. The simulation-based CPR education program consisted of lectures, skills practice, and high-fidelity simulations. Data were analyzed using a Wilcoxon signed-rank test. Results: The participants showed significant improvements in CPR knowledge (Z=5.03, p<.001), CPR attitude (Z=2.20, p=.028), and CPR performance confidence (Z=5.01, p<.001) after the simulation-based CPR education program. Conclusion: The simulation-based CPR education program improved CPR knowledge, CPR attitude, and CPR performance confidence of new nurses. These findings support the implementation of a simulation-based CPR education program to enhance clinical competence in emergencies.

This study presents an optimization model for battery scheduling in Advanced Air Mobility (AAM) operations considering congested (peak-hour) flight periods. Peak-hour demand concentration causes bottlenecks in vertiport charging/swapping facilities and accelerates battery degradation, reducing operational efficiency. A Mixed-Integer Linear Programming (MILP) model is developed, incorporating battery states (SoC, SoH), charger and swap-bay constraints, and power peak limits. Simulation results under peak and off-peak scenarios show that the proposed model reduces both delay time and total operating cost compared to average-demand scheduling. This study provides a quantitative decision-making basis for enhancing resource efficiency in AAM operations. The findings offer practical implications for improving AAM infrastructure efficiency and resource management policies.

Bavachinin (BVC), a prenylated flavonoid from Psoralea corylifolia seeds, is a reported natural PPAR agonist, but its metabolic efficacy and potential skeletal effects are unclear. This study examined the functional actions of BVC across various metabolic, inflammatory, and skeletal systems. BVC moderately activated PPAR, enhanced aP2 expression, and promoted adipogenic differentiation in hMSCs and in a de novo fat pad model. In high-fat diet-induced obese mice, BVC improved glucose tolerance and insulin sensitivity, restored Ser273-dependent PPAR target gene expression, and inhibited PPAR phosphorylation at Ser273 without inducing TZD-like side effects such as fluid retention, cardiac hypertrophy, or ENaC upregulation. BVC also suppressed pro-inflammatory cytokine expression and nitric oxide production in adipocytes, macrophages, and adipose tissue. In contrast to its metabolic benefits, BVC inhibited the osteoblast differentiation of hMSCs and impaired bone regeneration in a rat calvarial defect model. Hence, BVC acts as a selective PPAR modulator with metabolic and anti-inflammatory benefits but has adverse skeletal effects, highlighting its therapeutic potential benefits but noting important safety considerations regarding its use.

Graphite cores in nuclear reactors are critical components subjected to severe irradiation conditions. Despite the known susceptibility of graphite to radiation-induced damage, detailed microstructural analyses are limited. Existing works of literature have identified changes in crystallite morphology and orientation as early indicators of structural degradation, but the precise micro-mechanisms are not fully understood. This research explicates these micro-mechanisms using advanced analytical transmission electron microscopy (TEM) to examine irradiated graphite at doses up to 1 dpa (displacements per atom). TEM imaging and diffraction analysis captured detailed changes in crystallite structure. Even at low radiation doses (~ 0.1 dpa), a 15% alteration in crystallite morphology and orientation was observed. Significant crystal lattice rotations up to 5 degrees and micro-deformations were also detected. Additionally, the formation of micro-kinks and kink bands, ranging from 50 to 200 nm, were identified as potential deformation processes, consistent with phenomena in other layered materials. These results advance our understanding of the micro-mechanisms driving structural degradation and deformation in irradiated graphite. This research has significant implications for developing improved models and strategies to enhance the performance and longevity of graphite cores in nuclear reactors, contributing to the advancement of nuclear energy technology.

The growing demand for clean energy and sustainable technologies has intensified the need for efficient energy storage systems (EES) that support renewable energy integration while minimizing environmental impact. Biomass, an abundant and renewable resource, presents a cost-effective and eco-friendly pathway for producing advanced carbon materials, particularly heteroatom-doped graphene derivatives. This transformation aligns with circular economy principles by converting waste streams into high-performance materials for EES applications. This review provides a comprehensive analysis of biomassderived heteroatom-doped graphene materials, focusing on their synthesis, properties, and applications in electrochemical energy storage systems. It addresses a critical gap in the literature by systematically examining the relationship between biomass sources, doping strategies, and their impact on graphene’s electrochemical performance. The study highlights the role of heteroatom doping such as nitrogen, sulfur, phosphorus, and boron in enhancing graphene’s structural and electronic properties. These modifications introduce active sites, improve conductivity, and facilitate ion storage and transport, resulting in superior energy density, cycling stability, and charge–discharge performance in devices such as sodium/lithium-ion batteries, lithium-sulfur batteries, supercapacitors, and fuel cells. Recent advancements in green synthesis methods, including pyrolysis, hydrothermal carbonization, and chemical activation, are highlighted, focusing on their scalability and resource efficiency. By addressing both environmental and technological benefits, this review bridges the gap between laboratory research and practical applications. It underscores the critical role of biomass-derived graphene in achieving sustainable energy solutions and advancing the circular economy, offering a roadmap for future innovations in this rapidly evolving field.

케미컬 탱커의 화물 운용은 높은 전문성이 요구되기 때문에 국제해사기구는 상급 해기사에게 직무교육에서 필수 역량을 갖출 것을 요구하고 있다. 2023년 10월 선박직원법 개정으로 케미컬 탱커 승무 경력이 없는 대상자도 교육과정을 이수할 수 있게 됨에 따라, 현 재 기존의 승무 경력자와 무경력자가 동일한 교육과정을 함께 이수하는 문제가 발생하고 있다. 본 연구는 이러한 교육환경에서 교육 대 상자가 인식하는 교육 품질을 교육내용의 이해도, 교육내용의 중요도, 교육과정의 만족도로 구성하여 설문조사를 실시하였고, 교육의 성 취도인 평가점수와의 관계를 다중회귀분석을 통해 분석하였다. 연구 결과, 교육 대상자는 교육내용의 중요도, 교육과정의 만족도, 교육내 용의 이해도 순으로 중요하게 인식하고 있으며 교육 성취도는 교육내용의 이해도, 교육내용의 중요도, 교육과정의 만족도 순으로 증가하 는 영향력을 보였다. 직무교육의 교육 품질과 교육 성취도를 향상하기 위해서는 실무적인 교육내용으로 전체적인 이해도가 요구되는 문 제해결 능력을 높이는 방안이 효과적일 것이다. 본 연구는 케미컬 탱커 직무교육 대상자에게 빠른 친숙화와 역량 강화를 통해 안전한 화 물취급과 사고 예방에 도움을 줄 수 있을 것이다.

본 연구는 중소규모 고도정수처리시설(Y 정수장)에 적용된 세라믹막 여과공정의 운영 효율을 평가하고, 막오염의 주요 원인을 규명하며 실질적인 개선 방안을 제시하는 것을 목적으로 한다. 최근 세라믹막은 내구성과 내약품성이 우수하여 전오존 및 입상활성탄(GAC) 공정과의 조합에 적합한 기술로 주목받고 있으나, 막차압(TMP) 상승 및 장기 안정운영에 어려움이 존재한다. 본 연구에서는 2017년 실제 운영 데이터를 바탕으로, 망간 및 용존유기탄소(DOC)를 중심으로 한 원수 수질과 TMP 변화 간의 상관관계를 분석하였다. 그 결과, 수온역전이 발생하는 봄⋅가을철에 조류와 망간 농도가 증가하면서 TMP가 급상승하는 경향이 확인되었다. 또한 LC-OCD 분석을 통해 조류 유입 시기에는 바이오폴리머 농도가 증가하며 막오염에 직접적인 영향을 미치는 것으로 나타났다. 화학세정 실험에서는 pH 0.7의 황산이 망간, 철, 알루미늄 등의 무기성 침착물 제거에 가장 효과적인 것으로 확인되었으며, 세정 조건의 최적화 필요성이 강조되었다. 아울러 여과 유속의 불균형 및 계열 간 부하 집중이 TMP 상승에 영향을 미치는 주요 요인으로 분석되었고, 이에 따라 유량 제어 및 청정 주기 조정 등의 개선 전략이 제시되었다. 본 연구는 세라믹막 여과공정의 파울링 특성과 제어방안을 실증적으로 규명하였으며, 계절적 수질 변동에 대응하는 정수처리시설의 효율적인 운영 및 설계에 기초자료로 활용될 수 있을 것이다.

Maize (Zea mays. L) is one of the major sources of green fodder for livestock in Pakistan. Crop management plays a key role in obtaining high yields for green fodder. Fertilizer application, seed rate, and row spacing are critical components of crop management, which can significantly affect crop biomass. To determine the best production technology, a two-year (2021-2023) study was conducted at the research area of National Agricultural Research Center, Islamabad. Plant height, number of leaves, leaf area, green fodder yield per acre, and green fodder yield per hectare were recorded. Various row spacing (15 cm, 30 cm, 45 cm, and 60 cm), fertilizer ratio (N: P = 55:30, 65:40, 75:50, and 85:60), and seed rates (30 kg/ac, 35 kg/ac, 40 kg/ac, and 45 kg/ac) were applied. Results obtained experiments revealed that in both growing seasons, the maximum green fodder yield was obtained when fertilizer N: P ratio was 75:50 (green fodder biomass: 74.61 t/ha and 72.56 t/ha). Similarly, the optimal seed rate was found to be 40 kg/ac, which resulted in the highest green fodder yield (73.41 t/ha and 72.88 t/ha in two seasons). Furthermore, the plant of maize at row spacing of 30 cm was found to generate the maximum green fodder yield (72.39 t/ha and 72.40 t/ha, respectively). Green fodder yield per hectare was found to be positively correlated with plant height, number of leaves, and leaf area. These findings underscore the significance of applying a fertilizer ratio of N: P = 75:50, a seed rate 40 kg/ac, and a row spacing of 45 cm for higher yields of green fodder in maize crop.