The renewable energy has, currently, been used because of its eco-friendly energy such as no emission gas and less environmental pollution. Fuel cell electric vehicle (FCEV) using polymer electrolyte membrane fuel cell (PEMFC) uses the hydrogen as fuel to obtain the power by electrochemical reaction. The objective of this study is to investigate the flow characteristics of the hydrogen according to entrainment ratio for ejector of FCEV through comparison analysis with the air. As the results, the flow of hydrogen in ejector corresponds to turbulence with Reynold number 18,093. The pressure difference of the hydrogen between primary flow and secondary flow in ejector was about 16 times compared with that of the air. The mean velocity of the hydrogen in ejector outlet was faster about 15 times than the air.

흰점박이꽃무지(Protaetia brevitarsis) 유충은 고단백·고지방·미네랄이 풍부한 식용곤충으로 기능성 식품 및 사료 소재로 주목받고 있다. 본 연구에서는 열풍건조, 동결건조, 마이크로파건조 세 가지 방법으로 건조한 흰점박이꽃무지 유충의 영양성분과 유해물질 함량을 비교하여, 건조 공 정에 따른 품질 및 안전성 차이를 평가하고자 하였다. 동일한 조건에서 사육한 유충을 각 건조방법으로 처리한 후 수분함량을 보정하여 일반성분, 지방산 조성, 아미노산 조성, 무기질 함량 및 중금속 함량을 분석하였다. 그 결과, 마이크로파건조 처리군은 조단백질(57.6 g/100 g), 조지방(17.7 g/100 g), 올레산(10.5 g/100 g) 함량이 열풍건조 및 동결건조 처리군보다 유의하게 높았고, 식이섬유와 칼슘은 동결건조 처리군에서 가장 높게 나타났다. 모든 처리군에서 중금속 함량은 국내 식용곤충 관리 기준을 충분히 하회하여 안전성이 확보되었다. 이러한 결과는 동결건조가 항상 영양 소 보존에 가장 유리하다는 통념을 보완하며, 건조 효율과 영양 농축 정도가 곤충 체조직 특성과 건조 조건에 따라 달라질 수 있음을 시사한다. 따라 서 흰점박이꽃무지 유충의 가공 과정에서 마이크로파건조는 영양 농축과 품질 확보를 동시에 고려할 수 있는 실용적인 대안 건조공정으로 활용될 수 있을 것으로 판단된다.

Rapid post-earthquake retrofit decisions require reliable estimates of interstory drift ratio. Conventional field practices either depend on instrumented measurements constrained by sparse sensor coverage or rely on qualitative expert judgment. This study aims to develop a CNN-based interstory drift ratio prediction method for reinforced concrete columns using strain-derived damage images. Reinforced concrete columns are modeled and analyzed in OpenSees to obtain strains and displacements. Strain fields are converted into strain-derived damage images through threshold-based staging that encodes discrete damage states. Structural parameters are concatenated to the damage image by adding fixed-value columns so the network can read structural context in a single two-dimensional input. We design systematic comparisons to isolate the benefit of structural information and section coverage. First, models without structural parameters are trained. Second, single-parameter variants are trained where only one attribute is provided. Third, full-parameter models include all attributes. For each setting, both single-section and multi-section inputs are evaluated. Samples are split by case and then divided 80/20 into training and validation sets. Model performance is reported using RMSE, MAE, and R-squared. The proposed approach achieves accurate inter-story drift ratio prediction overall, with improved performance when all structural parameters and multi-section inputs are used.

This study was conducted to improve the stability of small barges used for remote bird monitoring at Capsosiphon fulvescens aquaculture farms. The monitoring accuracy is compromised by rolling and pitching motions induced by waves and wind. To address this problem, a damping system was developed to enhance barge stability. Field experiments were conducted at a farm to evaluate the effectiveness of the developed damping system. The rotational motions of the barge, with and without the damping system, were measured using a six-axis gyroscope sensor. The measurements were conducted at the Capsosiphon fulvescens farm located in Cheokchan-ri and Deokdong-ri, Gogeum-myeon, Wando-gun, Jeollanam-do across two periods: from October 5, 2024 to December 17, 2024 (Damping without) and from February 19, 2025 to April 15, 2025 (Damping with). The collected data were validated against wind speed records from the Korea Meteorological Administration. The results demonstrated that the damping system effectively reduced barge motion. Within a wind speed range of 0.1-9.0 m/s, the system achieved an average reduction of 7.11% in rotational motions. Its maximum performance was recorded at approximately 7.0 m/s wind speed where it achieved a reduction of 23.35%. These findings confirm the system significantly enhances barge stability and improves monitoring reliability.

This study investigates the vibration characteristics of an aluminum subframe for small and high-speed vessels through modal and resonance analysis using the finite element method (FEM). Due to the low stiffness and damping of aluminum, concerns arise over structural resonance and fatigue. A 3D model based on actual design drawings was analyzed to extract six natural frequencies and corresponding mode shapes. Significant deformation was observed in the first and second modes (90.65 Hz, 110.60 Hz), which may overlap with operational frequencies. The fifth mode (263.70 Hz) showed high amplitude with Y-axis concentration, indicating lateral resonance vulnerability. Deformation ratios were used to identify dominant vibrational directions. Based on the findings, design strategies such as structural reinforcement, RPM adjustment, and damping device application were proposed to improve vibration safety in the early design stage.

This study aims to evaluate the effects of installing electrodeless induction lamps on the intact stability of a coastal angling fishing vessel. The objective is to assess whether these alternative lighting systems can improve or maintain vessel stability while offering enhanced energy efficiency compared to conventional metal halide lamps. To achieve this, an 8.55-ton class coastal fishing vessel was selected, and hydrostatic analyses were conducted based on three kinds of lighting configurations: (1) metal halide lamps, (2) electrodeless induction lamps, and (3) a combined system of both. Inclining tests were performed for each condition, and the results were evaluated in accordance with the Standards for Stability and Full Load Waterline of Fishing Vessels and the Safety Standards for Standard Fishing Vessel Types established by the Korean Ministry of Oceans and Fisheries and the Adoption of the international code on intact stability by the International Maritime Organization. The core variables analyzed include the metacentric height (GM), righting lever curves, maximum righting moment and heel angle at maximum moment. These variables were used to assess the intact stability of the vessel under each lighting configuration. Inclination tests and hydrostatic analyses were performed using K-Ship and confirmed that the fishing vessel met all MOF and IMO stability criteria under various loading conditions and lamp configurations. Even when both metal halide and induction lamps were installed, the vessel satisfied the most stringent stability requirements with only a slight reduction in initial metacentric height. These results indicate that replacing or supplementing traditional lamps with induction lamps does not compromise vessel stability.

본 연구는 우울 감소 효과를 알아 보기 위해 ‘우울’, ‘우울감’, ‘동물매개중재’, ‘동물매개 치료’, ‘동물매개활동’, ‘동물매개교육’, ‘동물교감교육’ 등의 검색어를 활용하여 선정한 연 구들과 리뷰 논문들을 고찰하여 동물매개중재가 우울감소에 어떤 영향을 미치는지 살펴 보았다. 연구 결과 동물매개중재 프로그램은 대상자에 상관 없이 정서 안정과 우울 감소 에 효과적인 결과를 나타냈다. 동물과 함께 하면서 그리움, 기다림, 즐거운 기억 등 긍정 적 감정을 가질 수 있으며, 스킨쉽을 통해 정서 교감의 효과를 얻을 수 있어 우울감 극복 에 큰 의미를 지닐 수 있다. 더욱 다양하고 장기적인 개입 프로그램 적용을 통해 우울로 인해 생겨나는 많은 사회적 문제들을 줄이는데 도움을 줄 수 있으리라 기대한다.

This study aims to identify potential problems arising from the application of the Serious Accidents Punishment Act (SAPA), enforced in January 2022 to prevent serious industrial accidents in South Korea, to workplaces with 5 or more but less than 50 employees starting in January 2024. These smaller enterprises often face challenges such as limited safety-related budgets, and constraints in safety organizations and personnel. To address these concerns, a survey was conducted targeting CEOs of businesses with fewer than 50 employees, focusing on their understanding of SAPA and the establishment of countermeasures. Based on the survey results, this study seeks to propose viable alternatives and solutions for these businesses.

본 연구는 배수지에서 저수조를 포함한 대수용가의 수도꼭지에 이르는 구간에서 탁도와 잔류염소 농도의 시간적⋅공간적 변화를 분석하였다. 모니터링은 배수지, 중블록 유입 지점, 대수용가 유입 지점, 저수조 유출 지점, 수도꼭지 등 5개 지점에서 수행되었으며, 유량, 잔류염소, 탁도, pH, 전기전도도, 온도를 측정하였다. 연구 결과, 수돗물 이동 경로를 따라 잔류염소 농도는 점차 감소하고 탁도는 증가하는 경향을 보였다. 특히, 비업무시간대에는 수돗물 정체로 인한 수질 저하가 확인되었다. 또한, 저수조의 건전성을 평가하기 위해 반응계수를 산출한 결과, 시간에 따른 저수조 내부 건전성 저하와 수질 악화 가능성이 확인되었다. 본 연구는 수돗물의 이동 거리, 사용 시간대, 유량 변화 및 공급 방식에 따라 수질이 달라질 수 있음을 보여주며, 저수조에 의존하는 지역에서는 안전한 수돗물 공급을 위해 지속적인 모니터링과 관리가 필요함을 시사한다.

The seismic performance of lead-rubber bearings (LRBs) is significantly affected by both the axial force and loading rate they experience. Accurate assessment of LRBs’ seismic performance, therefore, requires realistic simulation of these forces and rates, as well as of the response of the isolated structure during seismic events. This study conducted a series of real-time hybrid simulations (RTHS) to evaluate the seismic behavior of LRBs in such conditions. The simulations focused on a two-span continuous bridge isolated by LRBs atop the central pier, exposed to horizontal and vertical ground motions. In the RTHS framework, the LRBs were physically tested in the laboratory, while the remainder of the bridge was numerically modeled. Findings from these simulations indicated that the vertical ground motion had a minimal effect on the lateral response of the bridge when isolated by LRBs.

In densely populated urban areas, reinforced concrete residential buildings with an open first floor and closed upper floors are preferred to meet user demands, resulting in significant vertical stiffness irregularities. These vertical stiffness irregularities promote the development of a soft-story mechanism, leading to concentrated damage on the first floor during seismic events. To mitigate seismic damage caused by the soft-story mechanism, stiffness-based retrofit strategies are favored, and it is crucial to determine an economically optimal level of retrofitting. This study aims to establish optimal seismic retrofit strategies by evaluating the seismic losses of buildings before and after stiffness-based retrofitting. An equivalent single-degree-of-freedom model is established to describe the seismic response of a multi-degree-of-freedom model, allowing for seismic demand analysis. By convolving the seismic loss function with the hazard curve, the annual expected loss (EAL) of the building is calculated to assess the economic losses. The results show that stiffness-based retrofitting increases first-story lateral stiffness by 20-40%, enhancing structural seismic performance, but also results in a rise in EAL compared to the as-built state, indicating lower cost-effectiveness from an economic perspective. The research concludes that retrofit options that increase first-story lateral stiffness by at least 60% are more appropriate for reducing financial losses.

본 연구에서는 baird paker agar (BPA)와 MC-media pad SA (MMPSA)의 황색포도상구균 검출효율과 정성 및 정 량 정확도를 비교하여 황색포도상구균 건조필름의 사용가 능성을 평가하였다. 본 실험에 사용된 재료는 마카롱(30건), 편육(30건) 및 김밥(30건), 총 90건을 실험 재료로 사용하 였다. 유통식품 90건의 황색포도상구균 검출효율 실험결과, BPA와 MMPSA의 검출효율은 48건(53.3%)으로 동일 하게 검출되었다. 또한 정량 정확도는 BPA와 MMPSA에 서 각각 2.0±0.8, 2.0±0.7 log CFU/g로 유의적인 차이가 나 타나지 않았다. 황색포도상구균의 정성 정확도 실험결과, BPA의 경우 97.7%, MMPSA의 경우 96.4%로 산출되어 유 의적인 차이가 나타나지 않았다. 황색포도상구균의 검출효 율, 정성과 정량 정확도 실험결과, BPA와 MMPSA 두 배지 에서 유의적인 차이가 나타나지 않아 황색포도상구균 정성 과 정량실험 시 MMPSA도 사용이 가능할 것으로 판단된다.

발효 느타리버섯재배부산물을 급이한 흰점박이꽃무지 유충의 영양성과 안전성을 검증하고자 참나무 발효톱밥으로 사육한 유충의 영양성분 과 유해물질을 비교분석하였다. 조단백질 함량은 발효 느타리버섯재배부산물을 급이한 유충(OMCB)에서 54.0%로 참나무 발효톱밥을 급이한 유 충(FOS) 47.2%보다 1.1배 많았다. 필수아미노산 중 류신은 OMCB에서 2.8%로 가장 높았고, FOS에서는 2.7%로 비슷한 수치였다. 비필수아미 노산은 OMCB에서 프롤린의 함량이 7.2%로 가장 높았고 FOS (5.6%)보다 1.3배 더 높았다. 무기질 중 칼륨은 OMCB (2771.2 mg/100 g)와 FOS (2765.0 mg/100 g)에서 비슷한 수치였고, 불포화지방산 중 올레산은 OMCB (58.2%)와 FOS (59.6%)에서 가장 높은 함량을 나타냈다. 유 해물질 분석 결과, OMCB와 FOS에서 납, 카드뮴, 비소 모두 식용곤충 중금속 기준에 적합하였고, 식중독균에 속하는 대장균과 살모넬라균은 모두 불검출되었다. 위 연구 결과에 따르면, 발효 느타리버섯재배부산물 급이 흰점박이꽃무지 유충은 단백질과 불포화지방산뿐만 아니라 다양한 영양성 분을 포함하고 있으며, 안전성 또한 검증되었으므로 식용으로 활용하기에 적합할 것으로 판단된다.

This study proposes an economically affordable method for retrofitting non-seismic detailed roof reinforced concrete beam-column joints (BCJs). The proposed method presents an innovative arrangement of steel plates designed to delay the propagation of joint shear cracks by externally applying compressive stress to the area surrounding the BCJs. Two full-scale sub-assemblage specimens for each exterior and interior roof BCJ, i.e., control and retrofitted specimens, were subjected to reversed cyclic loading to evaluate the proposed method. The retrofitted specimens displayed a preferable ductile behavior to the corresponding control specimen, with an enhancement in lateral strength by at least 100%. Furthermore, retrofitted specimens dissipated up to 13 times more energy than the control specimen by initiating a plastic hinge on beams or columns. These results indicated the effectiveness of the proposed method in preventing joint shear failure and improving the seismic behavior of roof BCJs.