The AlSi10Mg alloy has garnered significant attention for its application in laser powder bed fusion (L-PBF), due to its lightweight properties and good printability using L-PBF. However, the low production speed of the L-PBF process is the main bottleneck in the industrial commercialization of L-PBF AlSi10Mg alloy parts. Furthermore, while L-PBF AlSi10Mg alloy exhibits excellent mechanical properties, the properties are often over-specified compared to the target properties of parts traditionally fabricated by casting. To accelerate production speed in L-PBF, this study investigated the effects of process parameters on the build rate and mechanical properties of the AlSi10Mg alloy. Guidelines are proposed for high-speed additive manufacturing of the AlSi10Mg alloy for use in automotive parts. The results show a significant increase in the build rate, exceeding the conventional build rate by a factor of 3.6 times or more, while the L-PBF AlSi10Mg alloy met the specifications for automotive prototype parts. This strategy can be expected to offer significant cost advantages while maintaining acceptable mechanical properties of topology-optimized parts used in the automobile industry.

Aluminum-based composites are in high demand in industrial fields due to their light weight, high electrical conductivity, and corrosion resistance. Due to its unique advantages for composite fabrication, powder metallurgy is a crucial player in meeting this demand. However, the size and weight fraction of the reinforcement significantly influence the components' quality and performance. Understanding the correlation of these variables is crucial for building high-quality components. This study, therefore, investigated the correlations among various parameters—namely, milling time, reinforcement ratio, and size—that affect the composite’s physical and mechanical properties. An artificial neural network model was developed and showed the ability to correlate the processing parameters with the density, hardness, and tensile strength of Al2024-B4C composites. The predicted index of relative importance suggests that the milling time has the most substantial effect on fabricated components. This practical insight can be directly applied in the fabrication of high-quality Al2024-B4C composites.

This review examines the microstructural and mechanical properties of a Ti-6Al-4V alloy produced by wrought processing and powder metallurgy (PM), specifically laser powder bed fusion (LPBF) and hot isostatic pressing. Wrought methods, such as forging and rolling, create equiaxed alpha (α) and beta (β) grain structures with balanced properties, which are ideal for fatigue resistance. In contrast, PM methods, particularly LPBF, often yield a martensitic α′ structure with high microhardness, enabling complex geometries but requiring post-processing to improve its properties and reduce stress. The study evaluated the effects of processing parameters on grain size, phase distribution, and material characteristics, guiding the choice of fabrication techniques for optimizing Ti-6Al-4V performance in aerospace, biomedical, and automotive applications. The analysis emphasizes tailored processing to meet advanced engineering demands.

식품 포장 분야에서 바이오센서와 바이오폴리머 기반 나 노복합체, 즉 바이오나노복합체의 통합이 점차 산업 전문 가들에 의해 인식되고 있으며, 이는 식품의 품질과 안전 에 대한 우려가 증가함에 따라 주도되고 있습니다. 식품 포장에 내장된 바이오센서는 포장된 상품의 미생물에 의 한 변질을 지속적으로 모니터링함으로써 식품의 완전성을 유지하는 핵심 요소로 업계를 변화시킬 준비가 되어 있다. 동시에, 탁월한 기계적, 열적, 광학적, 항균적 특성으로 인 해 바이오폴리머 기반 나노복합체의 연구와 적용이 크게 확대되었다. 이러한 특성은 이들을 혁신적인 포장 솔루션 에 적합한 주요 재료로 만든다. 그러나 지능형 식품 포장 시스템 발전에 바이오센서와 바이오나노복합체를 사용하 는 잠재적인 장애물과 전망을 탐구하는 것은 아직 충분하 지 않다. 바이오나노복합체와 바이오센서의 융합을 제안 하는 것은 스마트 포장 산업을 재정의하는 획기적인 단계 로, 이 기술들을 더 깊이 이해하여 지속 가능하고 경제적 으로 실행 가능한 스마트 포장 옵션의 개발을 촉진할 필 요성을 강조한다. 이 리뷰는 바이오센서와 바이오나노복 합체에 대한 기존 연구와 개발 동향을 철저히 검토하고, 가까운 미래에 스마트 식품 포장 산업에서 진전을 이끌어 낼 앞으로의 도전과 기회를 강조하는 데 전념하고 있다.

Hydrogen peroxide (H2O2) is widely used in bleaching treatments in the pulp and paper industry, in wastewater treatment, and as a food additive. However, H2O2 solutions are unstable and decompose slowly when subjected to external factors such as light, high temperatures, or metal compounds. Therefore, a simple and reliable method to measure the concentration of H2O2 is required for its proper use in various applications. We determined the concentration of an H2O2 solution by measurement at a single wavelength (249 nm) without any reagents or complex analytical procedures. In the present work, the measurable concentration of H2O2 was as low as 0.015 wt% (4.41 mM) and as high as 0.300 wt% (88.2 mM), with high linearity (99.99% at 249 nm) between the concentration of H2O2 and the optical density (OD) values. In addition, the method could be used to measure the concentration of H2O2 in a peracetic acid solution without interference from acetic acid and peracetate ion.

Ainsliaea acerifolia leaves are registered with the Ministry of Food and Drug Safety as edible herbal materials in Korea, and research is underway to explore their potential in developing functional foods, cosmetics, and pharmaceuticals. In this study, we developed an analytical method using HPLC-DAD to quantify three key compounds—chlorogenic acid, isochlorogenic acid A, and 1,5-dicaffeoylquinic acid—in A. acerifolia leaves extract. This method has been optimized and validated for specificity, accuracy, precision, limit of quantification (LOQ), and linearity. The correlation coefficients (r²) for the calibration curves exceeded 0.9962. The limits of detection (LOD) and quantification (LOQ) were 0.3012 and 0.9128 μg/mL for chlorogenic acid, 0.1182 and 0.3582 μg/mL for isochlorogenic acid A, and 0.2342 and 0.7098 μg/mL for 1,5-dicaffeoylquinic acid, respectively. The net recovery rates for accuracy testing were 105.13% for chlorogenic acid, 105.37% for isochlorogenic acid A, and 100.37% for 1,5-dicaffeoylquinic acid. All parameters assessed with this newly developed method fell within the acceptable ranges specified by ICH guidelines. These findings demonstrate that the method is robust and reliable for accurately identifying and quantifying chlorogenic acid, isochlorogenic acid A, and 1,5-dicaffeoylquinic acid in both routine analysis and large-scale extraction process of A. acerifolia leaves.

본 연구는 영유아교사의 근무환경과 이직의도 관계를 알아보고 감정노동이 이 두 변수를 조절하는지 확인하는 데 목적이 있다. 연구를 위해 영유아교사 199명을 대상으로 빈도분석, 기술통계분석, 상관분석을 실시하였으며, 인구통계학적 주요변인의 차이검증을 위해 t-검증 (t-test) 및 일원분산분석(one-way ANOVA)을 실시하였다. 또한 감정노동 조절효과 검증을 위해 위계적 회귀분석과 단순기울기 분석을 적용하였다. 분석 결과, 근무환경의 하위 변인들은 감정노동의 내면적 행동에는 정적 상관관계를, 이직의도에는 부적 상관관계를 보여주었다. 영 유아 교사들의 감정노동은 표면적 행동과 내면적 행동에 정적 상관관계로 나타났으며 감정노 동의 표면적 행동은 이직의도와 정적 상관관계가 있는 것으로 나타났다. 낮은 물리적 환경과 대인관계에 기반 한 감정노동은 이직의도를 유도하지만 반면 감정노동은 근무환경과 이직의 도 간의 조절요인으로 작용하였다. 근무환경의 개선방안으로 영유아교사의 업무에 대한 코칭 개입 방법은 궁극적으로 이들의 이직의도를 낮추는 효과적인 방안일 수 있다. 즉 정서적인 지 지를 통해 스트레스적인 근무 환경을 정서 안정적이고 긍정적인 환경으로 변경하고, 물리적으 로 교재․교구비 지원, 근로시간 보장, 처우 개선을 통해 영유아 교사들의 근무환경에 대한 만족도를 높이는 것이 요구된다. 본 연구는 궁극적으로 코칭기법을 중심으로 교사 심리 상담 과 같은 정서적 지원프로그램을 제공하여 그들의 이직의도를 낮추는 방안을 제언한다.

목적 : 본 연구는 20대 건강한 초보운전자를 대상으로 음주운전이 운전에 미치는 영향을 알아보고자 하였다. 또한 초보운 전자의 음주운전에 대한 인식을 높이기 위한 근거를 제공하는 것을 목적으로 하였다. 연구방법 : 단면적 연구 수행으로 22명이 연구에 참여하였으며 연구 참여자는 음주 운전을 시뮬레이션하기 위해 3가지 음 주 안경(Fatal Vision Gogles, FVG)을 번갈아 착용하고 운전 시뮬레이터(GDS-300, Gridspace, 서울, 한국)를 사용하 였다. (1) 위약 고글, (2) 저용량 알코올 고글, (3) 고용량 알코올 고글의 세 가지 실험 조건에서 UFOV 평가(처리 속도, 분리 집중력, 선택적 집중력), 인지 평가, 점수 차감 및 결격을 사용하여 운전 능력을 측정하였다. 결과 : 연구 참여자의 평균 연령과 운전 경력은 각각 21.6±2.3세와 23.6±16.2개월이었다. 수집한 자료를 분석한 결과, 처리 속도, 분리 집중력, 선택적 집중력은 세 가지 조건에서 유의한 차이가 있었다. 반면에 인지 평가 점수, 운전점수 감 점 및 결격은 세 가지 조건에서 유의한 차이가 없었다. 결론 : 본 연구의 결과는 20대 초보운전자의 음주운전이 인지 기능, 운전점수 감점, 운전 결격에 영향을 미치지 않았으나 처리 속도, 분리 집중력, 선택적 집중력에 영향을 미친다는 것을 보여주었다. 본 연구의 결과를 바탕으로 실제 운전 중 음주 운전자에게 예측할 수 없는 돌발 상황이 발생할 때 상당한 위험을 초래할 수 있음을 제언하는 바이다.

The world is transitioning towards sustainable agriculture, which includes reducing chemical fertilizers and increasing the adoption of eco-friendly materials. Red clay, known for its colloidal properties, adsorption, and ion exchange capabilities, has become eco-friendly due to its non-toxic nature. However, when red clay is applied in its insoluble powdered form, its absorption by plants is limited. Processed red clay (PRC) was developed to overcome these limitations, and microbial formulations containing Lactobacillus fermentum (MFcL) were applied alongside it. Chlorophyll content and fluorescence values decreased over time after cucumber transplantation. However, co-application of PRC and MFcL resulted in higher chlorophyll content than PRC alone, suggesting that this combination could alleviate plant growth reduction caused by stress. Although the total yield of cucumbers was highest in the NF group, yield per plant increased by more than 10% in the PRC treatment compared to NF. Additionally, yield was higher when PRC was applied alongside MFcL than with MFcL alone. While the proportion of marketable fruits decreased over time in the NF treatment, it increased in the PRC treatment. Soil analysis revealed that PRC application increased soil pH by 3% and available silicon content by 7.6% compared to NF, while available phosphate levels decreased by 13%. Analysis of microbial density in the soil showed that bacteria levels significantly increased by 2-fold in PRC+MFcL compared to NF, while actinomycetes decreased by 1.5-fold. In conclusion, PRC treatment positively influenced cucumber growth, and co-application with microbial fertilizers demonstrated a synergistic effect.

Wet pavement friction decreases due to the increase in water film thickness (WFT), leading to a significant increase in vehicle crashes occurrences. The British Pendulum Test described in ASTM E303-93 is one of the methods used to measure pavement friction in wet conditions for the input of geometric design and pavement management systems. The British Pendulum Number (BPN) in wet conditions varies with WFT. Following ASTM E303-93 standard procedures, water film thickness was simulated by spraying water on the pavement surface. However, the measurement of BPN did not include specific information about the thickness of the water film present during testing. To address these issues, WFTs and BPNs were measured using artificial rainfall generated by a rainfall simulator across various intensities, drainage lengths, pavement slopes, and pavement surfaces. This study aims to investigate the influence of water film thickness on BPN for wet pavement friction and provide the WFT corresponding to each BPN measurement for different surface types. BPNs of three test slabs, including a smooth surface and tined surfaces with 16 mm and 25 mm spacing, were measured under wet conditions by spraying water, and by creating water film thicknesses using a rainfall simulator. This study demonstrates that the BPNs of non-tined surfaces and longitudinally and transversely tined surfaces with 25mm spacing exhibit a significant decrease with increasing water film thickness, while those with 16mm spacing show a slight decrease. These findings can be attributed to the lower friction observed in both non-tined and longitudinally tined pavements, in contrast to surfaces with transverse tinning.