The PCHE(Printed Circuit Heat Exchanger)-type heat exchanger, which was fabricated by etching and diffusion bonding, was used to hydrogen station, VHTR(Very High Temperature Reactor), SMR and so on. The hydrogen station equipped with PCHE-type heat exchanger is necessary to inject the hydrogen gas into facilities, for instance, such as HFCV(Hydrogen Fuel Cell Vehicle) and power systems. The purpose of this study is to investigate the thermal characteristics of thin plate of PCHE depending on constraint conditions through numerical analysis. As the results, it showed that thermal stress of thin plate, which was not performed diffusion bonding at all, was larger than that, which was performed perfect diffusion bonding, and its maximum difference was about 3 times. Further it was confirmed that the thermal characteristics of thin plate could be obtained by investigating the heat flux.

서울 시내 유통점과 온라인 쇼핑몰에서 구입한 홍삼함 유식품 66건과 건강기능식품 홍삼제품 35건의 기능 성분 인 진세노사이드 함량을 비교·분석하였다. 홍삼함유식품 66건 중 전통시장에서 구입한 2건은 진세노사이드가 검출 되지 않았고 64건의 제품에서는 진세노사이드 함량에 대 한 기준은 없지만 일일 섭취량 기준 0.55-71.56 mg을 함 유하고 있었다. 건강기능식품의 홍삼제품은 진세노사이드 평균 함량이 분말형 제품을 제외하고 일일 섭취량 기준 18.23 mg으로 홍삼함유식품의 8.80 mg 보다 약 2배 정도 가 많았다. 홍삼과 흑삼 비교 시 진세노사이드 함량은 홍 삼 제품이 흑삼 제품보다 많거나 비슷하였으나 분말형 제 품의 경우 흑삼 제품이 2배 많았다. 제형별 진세노사이드 평균 함량은 일일섭취량 기준 농축액 21.95 mg으로 가장 많고 분말 형태 12.54 mg, 스틱형 7.36 mg, 파우치형이 4.10 mg 순이었다. 흑삼제품은 고기능성으로 알려져 있으 나 대부분 일반 식품으로 판매되고 있어 건강기능식품 수 준의 관리와 규제가 필요할 것으로 보이며 흑삼의 규격기 준 설정 이후에는 흑삼제품의 기능성분 함량 재평가가 필 요할 것으로 판단된다. 스틱형이나 농축액 제품의 경우 건강기능식품뿐만 아니라 일반식품인 액상차, 홍삼음료로도 널리 판매되고 있어 식품유형 표시를 명확히 해야 할 것 으로 보인다. 최근 면역력 향상을 위한 소비자의 관심 증 가로 다양한 건강기능식품의 수요가 늘어나고 있다. 따라 서 홍삼을 함유한 식품을 섭취 목적에 맞게 선택할 수 있 도록 정확한 함량정보 제공을 위해 다양한 제품에 대한 지속적인 품질평가가 필요하다.

This study aimed to provide an accurate estimate of sodium intake from jangajji by examining the changes in sodium content according to the type of jangajji and the length of storage period, specifically differentiating between the solid ingredients and the seasoning liquid. It focused on six types of jangajji: chili pepper, perilla leaf, onion, radish, garlic scape, and cucumber. The sodium content in the solid ingredients and the seasoning was measured using a salinometer and ICP-AES. The results indicated that across all types of jangajji, the seasoning liquid consistently contained significantly higher levels of sodium than the solid ingredients. When comparing the sodium content measured by ICP-AES with that from a salinometer, the salinometer readings were significantly lower for both the solid ingredients and the seasoning liquid in all types of jangajji. Additionally, when comparing the sodium content of the solid ingredients with that listed in the nation’s representative nutritional databases, a substantial discrepancy was noted, with some cases potentially overstating the actual sodium intake from jangajji. Overall, this study suggests that an urgent review should be conducted to identify and resolve the causes of such discrepancies and accurately estimate the actual sodium intake from jangajji.

목적: 본 연구는 학습과정에서 보일 수 있는 심리적인 특성과 성격적인 요인을 진단할 수 있는 U&I 학습성격유형검 사를 이용하여 학습성격에 따른 시기능훈련 전·후 향상도를 알아보고자 하였다. 방법 : 안과질환 및 전신질환이 없는 성인 남녀 34명을 대상으로 학습성격유형을 분류하고 양안시검사 결과에 따라 적합한 시기능훈련 도구를 적합한 선정하여 시기능훈련을 실시하였다. 결과 : 학습성격유형과 시기능훈련을 상관 분석한 결과 행동형은 음성상대조절력과 양의 상관관계를 보였으며 규범형은 원거리 양성융합버전스 회복점과 양의 상관관계를 보였다. 탐구형은 양성상대조절력과 음의 상관관계를 보였고 이상형은 음성상대조절력과는 양의 상관관계, 근거리 양성융합버전스 흐린점은 음의 상관관계를 보였다. 학 습성격유형에 따른 시기능훈련 효과를 분석한 결과 융합용이성에서 규범형이 이상형보다 시기능훈련 전·후 융합 용이성의 효과가 유의하게 증가하였다. 결론 : 학습성격유형에 따른 시기능훈련 효과에 차이가 있음을 확인할 수 있었으며 그에 맞는 훈련법을 고안한 다면 더 체계적인 시기능훈련 방법을 적용할 수 있을 것으로 사료된다.

The research aimed to develop a high-efficiency plate-type heat exchanger for exhaust gas using computational fluid dynamics (CFD) thermal analysis based on the plate shape, and to identify the optimal shape. Following this, a water/air plate heat exchanger was manufactured, and its characteristics were studied experimentally. As the Re number increases on the gas (or air) side, the heat transfer rate increases significantly, whereas an increase in the Re number on the water side leads to a smaller increase in heat transfer. This is attributed to the larger convective heat resistance on the gas side, causing a substantial reduction in gas-side heat resistance as gas velocity increases, resulting in a considerable overall reduction in heat resistance. The fluid flow pressure drop showed similar results between the CFD calculations and experimental outcomes.

This study evaluated the consumers’ demands and points of improvement for restaurant meal replacement through importance–performance analysis by the restaurant meal replacement segment market using food involvement. The results were as follows. First, after segmenting the restaurant meal replacement market using food involvement, it was classified into three markets (multiple involvements, exploration-oriented, and product quality-oriented). Second, an analysis of the importance of restaurant meal replacement selection attributes revealed taste, sanitation, quality, freshness, price, saving time, texture, ingredients, preparation process, and quantity to be highly important. An analysis of the differences according to the market type revealed the multiple involvement type to be more important than other groups, considering the restaurant meal replacement selection attribute element. Third, an analysis of the importance-performance analysis of restaurant meal replacement selection attributes revealed that quantity and price as the selection attributes that needed to be improved first in all three markets. In addition, in the multiple involvement type, food additives appeared as a selection attribute requiring priority improvement, revealing the characteristics of a market that cares about diet and health.

PURPOSES : The wedge-type anchorage system requires a complex analysis of not only the tensile stress of the CFRP plate, but also the compressive stress and shear stress generated by the wedge action. The purpose of this study is to find a composite material failure theory that is suitable for analyzing the behavior of wedge-type anchorage system among various failure theories. METHODS : In this study, numerical analysis of various composite material failure theories was performed to analyze the anchorage strength and failure mode of the wedge-type anchorage system according to each failure theory, and compared with actual test results to determine the composite material failure theory most suitable for analyzing the behavior of a wedge-type anchorage system. RESULTS : Since the Maximum Stress failure theory shows similar results to the actual test in terms of failure mode and anchorage strength, there is no significant problem in applying it to the wedge-type anchorage system. However, it is judged to be difficult to apply under property conditions where interactions between stresses are highlighted. The Tsai-Hill and Tsai-Wu failure theories are considered unsuitable for application to wedge-type anchorage systems because the wedge angle conditions at which the most advantageous anchorage strength occurs are significantly different from other theories and the fracture type cannot be predicted. The Hashin-Rotem failure theory is considered to be the most appropriate to apply as a failure theory for the wedge-shaped anchorage system because the anchorage strength was slightly lower than the actual test results, but there was no significant difference, and the failure mode was consistent with the test results. The Hashin failure theory is judged to be unsuitable for application as a failure theory for the wedge-type anchorage system because the anchorage strength and failure mode were interpreted differently from the actual test results. CONCLUSIONS : The Hashin-Rotem failure theory was presented as the composite material failure theory most suitable for analyzing the behavior of wedge-type anchorage system.

The importance of urban green space creation is increasingly recognized as the most realistic and efficient approach for fine dust mitigation in urban areas. Particularly considering the characteristics of domestic cities, the application of buffer green spaces along roads can maximize the efficiency of fine dust reduction without the need for separate green space creation. Accordingly, this study analyzed the fine dust mitigation effects based on the types of plantings in the central dividers and roadside trees in Jeonju City, Jeollabuk-do. To do this, we controlled various external variables of urban space and considered the planting arrangement types in the central dividers, carrying out the analysis using a CFD simulation. The simulation results confirmed that the central dividers with plantings demonstrated more effective ultrafine dust reduction than those without. Moreover, the arrangement of roadside trees showed a greater ultrafine dust reduction effect when adopting a multilayered structure compared to a single layer. Based on these findings, we concluded that installing both trees and shrubs simultaneously in the central dividers and along roads was effective for ultrafine dust mitigation. On this basis, we quantified the dust reduction effects of plants in urban street environments and proposed planting guidelines for roadside green spaces to improve air quality.

In this study, a conjoint analysis was conducted to derive a combination of fishing quota management system by fish species preferred by fishermen. In the analysis, detailed levels were set according to each attribute of the system. For analysis, this study conducted a design question survey for conjoint analysis on 303 fishermen engaged in fishing activities in the offshore and coastal sea. The Conjoint analysis was conducted on all fishermen, offshore fishermen and coastal fishermen. In addition, an analysis was conducted on TAC system participants and non-TAC system participants, and the targets were classified for comparison according to the characteristics of fishermen. Fishermen’s preference for the system confirmed for six attribute (“catching fish even if there is no fishing quota”, “how to allocate fishing quota”, “fishing quota management agency”, “upper limit of fishing quota,” “Possibility of Trading in the Fishing Quota”, and “Application of Other Regulations.”) and the detailed level of each attribute. As a result of the analysis of the importance of attributes, fishermen thought that “fishing quota management agency (24.1%)” was very important, and “catching fish even if there is no fishing quota (23.9%)” and “how to allocate fishing quotas (22.9%)” were also given some importance.

횡하중에 작용하는 철근 콘크리트 기둥은 연성능력 확보를 위해 띠철근의 양 단부를 135° 구부려 시공하는 상세가 요구된다. 그러 나 이러한 띠철근 상세는 시공이 매우 까다로와 실제 현장에서는 제대로 시공이 되지 않기도 한다. 이를 대체하기 위해 본 논문에서는 강재 클립형 연결장치가 적용된 철근 콘크리트 기둥에 대해 횡방향 반복가력 실험을 수행하고 그 구조적 성능을 평가하였다. 총 4개 의 실험체가 제작되었으며 주요 실험변수는 강재 클립형 연결장치 및 고강도 콘크리트 사용 여부이다. 또한 대상 구조물에 대해 3차 원 유한요소해석 모델을 개발하고 이에 대한 비선형 해석을 수행하였으며, 해석 및 실험결과를 비교하고 분석하였다. 그 결과 강재 클 립형 연결장치가 설치된 콘크리트 기둥이 반복 횡하중에 대해 기존의 표준갈고리 상세를 지닌 콘크리트 기둥과 동등한 혹은 그 이상 의 성능을 지니고 있으며, 개발된 유한요소해석 모델이 실험결과를 정확히 잘 예측하는 것으로 나타났다.

PURPOSES : The primary objective of this study is to analyze the relationship between the factors that affect traffic incident duration in the mainline, tunnel, and ramp segments of an expressway. In addition, this study derived the most suitable statistical prediction model based on various incident duration distributions. METHODS : South Korean expressway crash data for 11 years, from 2011 to 2021, were analyzed. The incident durations on the mainline, tunnel, and ramp segments were selected using the accelerated failure time model, which is a parametric survival analysis approach. RESULTS : The mainline segment showed that the incident duration increased during accidents, including guard pipe collisions, multivehicle collisions, and snowfall. In particular, collisions in a tunnel with shoulder facilities increase the incident duration, while decreasing the time in the ramp segment. CONCLUSIONS : The incident duration model for each segment type yielded the most accurate results when applying a log-logistic distribution.

In the case of a school building, even though it is a regular structure in terms of plan shape, if the masonry infill wall acts as a lateral load resisting element, it can be determined as a torsionally irregular building. As a result, the strength and ductility of the structure are reduced, which may cause additional earthquake damage to the structure. Therefore, in this study, a structure similar to a school building with torsional irregularity was selected as an example structure and the damping performance of the PC-BRB was analyzed by adjusting the eccentricity according to the amount of masonry infilled wall. As a result of nonlinear dynamic analysis after seismic reinforcement, the torsional irregularity of each floor was reduced compared to before reinforcement, and the beams and column members of the collapse level satisfied the performance level due to the reduction of shear force and the reinforcement of stiffness. The energy dissipation of PC-BRB was similar in the REC-10 ~ REC-20 analytical models with an eccentricity of 20% or less. REC-25 with an eccentricity of 25% was the largest, and it is judged that it is effective to combine and apply PC-BRB when it has an eccentricity of 25% or more to control the torsional behavior.

Nowadays, transferred type arc plasma torches have been widely present in industrial applications, in particular, using melting pool of electrically conducting materials such as arc furnace, welding and volume reduction of radioactive wastes. In these applications, the melting pools are normally employed as an anode, thus, heat flux distributions on anode melting pool need to be characterized for optimum design of melting pool system. For this purpose, we revisited the one-dimensional model of the anode boundary layer of arcs and solved governing equations numerically by using Runge-Kutta method. In addition, the direct melting process of non-combustible wastes in the crucibles were discussed with the calculation results.