As people spend most of their time indoors, managing indoor air quality (IAQ) has become critical. However, current standard test methods for paints using undiluted solutions do not reflect actual construction practices where thinners are added. This study aims to investigate the effects of dilution ratios on TVOC and formaldehyde (HCHO) emissions. Ten types of paints were tested using a small chamber method under undiluted (Org.) and diluted (Dil. 1, Dil. 2) conditions based on manufacturers’ specifications. The results showed that HCHO emissions were not significantly affected by dilution. However, TVOC emission patterns were categorized into four groups. Notably, some oil-based paints showed an initial suppression followed by a reversal phenomenon where emissions exceeded the original solution after three days. These findings suggest that the current test standards may underestimate the actual risk, highlighting the need to revise the regulations to reflect real-use dilution conditions.

This study evaluated the effects of dietary cellulose-to-starch ratios on nutrient digestibility, fermentation characteristics, and greenhouse gas emissions in the rumen. For 48 h of in vitro rumen incubation, each substrate (0.3 g) was incubated with rumen fluid mixture (30 mL) in quadruplicate. Six treatments were formulated with different ratios of structural (cellulose-based) and non-structural (starch-based) carbohydrates (10:0, 8:2, 6:4, 4:6, 2:8, and 0:10). After incubation, total gas emission was measured and analyzed for CO2 and CH4. The remaining contents were centrifuged to determine rumen fermentation characteristics and digestibility. The crude protein level of all treatments was maintained at 15% by combining soybean meal and urea. After incubation, in vitro dry matter digestibility (IVDMD) and organic matter digestibility (IVOMD) increased linearly with higher starch content, while ammonia-N and total volatile fatty acid (VFA) concentrations decreased quadratically. In addition, acetate concentration and the acetate to propionate (A:P) ratio increased along with starch content (p<0.05), whereas propionate concentration decreased (p<0.05). As starch content increased, CO2 and CH4 emissions based on DM increased linearly (p<0.05) but decreased (p<0.05) quadratically and linearly based on DMD and OMD, respectively. Therefore, this study concluded that the dietary cellulose-to-starch ratios affected rumen fermentation characteristics and greenhouse gas emissions, particularly methane mitigation by increasing dietary starch content. Further study should be conducted to determine the concentrate-to-forage ratio that reduces greenhouse gas emissions without adverse effects on animal performance.

As South Korea enters a super-aged society, the number of nursing hospitals has increased rapidly, yet there are no legal staffing standards for caregivers. This absence creates a severe vulnerability regarding evacuation safety during fires. This study quantitatively analyzes evacuation times using a simulation, applying a '3:1 patient-to-caregiver ratio' based on Japanese standards. Four scenarios combining Day/Night shifts and Existing/Proposed (3:1) staffing were compared using a real hospital model. The results indicate that applying the 3:1 standard reduced the total evacuation time by 41% (1210s → 710s) during the day and 22% (1290s → 1000s) at night compared to existing staffing levels. This empirically demonstrates that the patient-to-caregiver ratio is a key variable in evacuation performance and suggests an urgent need for legal minimum staffing standards to ensure patient safety.

This study examined the quality characteristics of rice layer cakes prepared using various levels of allulose (ALL). ALL was used to substitute 0% (control group), 25% (ALL-25 group), 50% (ALL-50 group), 75% (ALL-75 group) and 100% (ALL- 100 group) of white sugar (WS) in the manufacture of rice layer cake. The substitution of WS with ALL decreased the pH of the cake batter but increased its specific gravity (p<0.001). The ALL-100 group exhibited higher moisture content than the control (p<0.05), and baking loss increased with increasing ALL levels (p<0.01). The volume index of the cake decreased significantly as the proportion of ALL increased (p<0.001). Low lightness, high redness, and high yellowness were observed in the experimental groups at higher proportions of ALL (p<0.001). The ALL-100 group exhibited significantly higher hardness, adhesiveness, cohesiveness, springiness, gumminess, and chewiness than the other groups (p<0.05). Sensory evaluation revealed that cakes with higher ALL levels had stronger perceived intensity with respect to “color,” “sweet aroma,” and “salty taste.” The acceptance test indicated that the ALL-25 group was comparable to or more acceptable than the control in all attributes except for color.

Near infrared reflectance spectroscopy (NIRS) is widely used to assess the nutrient composition of forages. In forage, the leaf to stem ratio of alfalfa greatly affects its forage quality, with a high ratio of leaf indicated as high quality. This study aimed to evaluate the predictability of the alfalfa leaf-to-stem ratio and feed value using NIRS. Alfalfa hay was manually separated into leaves and stems by hand and the analysis samples were then made in the controlled range between 0 and 100%. Calibration models (n=320) were developed using modified partial least squares regression (MPLS) based on cross-validation. The optimal calibrations were selected based on the highest coefficients of determination in cross-validation (R2) and the lowest standard error of cross-validation (SECV). The prediction accuracy for the leaf-to-stem ratio (SECV, 5.95 vs. 5.71%; R2, 0.91 vs. 0.91) in alfalfa hay was comparable. For leaves, the standard error of calibration (SEC) was 4.94% (R2=0.94), and for stems, it was 4.81% (R2=0.94). The leaves and stems of the SEC were 4.94% (R2=0.94) and 4.81% (R2=0.94), respectively. The prediction accuracy for feed value, based on the leaf-to-stem ratio, predicted SECV values of 0.92% (R2=0.88) for crude protein (CP) content, 1.92% (R2=0.91) for neutral detergent fiber (NDF) content, 1.36% (R2=0.91) for total digestibility nutrient (TDN) content, and 9.86 (R2=0.81) for relative feed value (RFV). The results of this study demonstrate the potential of the NIRS method as a reliable tool for predicting the leaf-to-stem ratio of alfalfa hay, and show available techniques for routine feed value evaluation.

배추는 한국에서 연중 소비되는 김치의 주 원료이며, 노지에서 주로 재배되고 있다. 온실 재배 수경재배 시 스템은 기후 변화에 영향을 받지 않고 토양을 대신한 배지를 사용함으로써 토양 병원균으로부터 작물을 보호할 수 있어 재배 안정성을 확보할 수 있다. 수경재배용 배지 중 일부는 재사용이 가능하고, 이러한 배지의 조성은 작물 생 장과 품질에 영향을 줄 수 있다. 본 연구는 재사용 코이어 배지 또는 인공배지를 첨가한 배지 조성에 칼슘 공급원을 처리하여 배추(Brassica rapa ‘Bulam Plus’)를 수경재배 했을 때 배액과 생육에 미치는 영향을 알아보고자 10주동 안 수행하였다. 배지 조성은 재사용 코이어: 피트모스: 펄라이트 비율(v/v/v)을 각각10:0:0, 7:2:1, 5:3:2의 세 처리 와 각 처리에 칼슘 공급원인 CaSO4(G)와 CaO(Q)를 200g/m2 혼합한 총6가지 처리(G10:0:0, G7:2:1, G5:3:2, Q10:0:0, Q7:2:1, Q5:3:2)하였다. 배액량, 배액의 pH와 EC, 생육, 잎끝마름(Tipburn)발생을 조사하였다. 배추 생육이 증가함에 따라 모든 처리에서 배액률은 감소하였고, 처리 9주째는 20% 미만으로 감소하였다. 배액의 EC는 G 처리가 Q 처리 보다 높았으나 배액의 pH는 Q 처리가 높았다. 처리 10주째 배추의 초장, 엽수, 엽폭은 처리 간 유의성이 없었다. 엽 록소함량값(SPAD)은 G7:2:1과 G5:3:2처리에서 높게 나타났다. 잎의 당도와 건물중은 Q5:3:2처리에서 높았으며, 건물 중이 관찰되었다. 배추의 잎끝마름 발생은 처리 25일째 관찰되었으며, G7:2:1처리에서 가장 높았다. 이상의 결과를 종합할 때 CaO가 첨가되고 재사용 코이어 50% 함유된 Q5:3:2처리에서 수경 재배된 배추 생육이 양호하였다. 본 연 구는 간이 시설을 적용된 수경재배 시스템에서의 안정적 배추 재배를 위해 재사용 코이어 배지와 칼슘 공급원에 관 한 기본 정보를 제공하고자 하였다.

본 연구는 정원소재용 자생식물인 돈나무를 건전한 묘목으로 생산하기 위해 적정 차광비율을 구명하고자 수행되었다. 차광은 0%(T0), 55%(T55), 75%(T75)의 3수준으로 처리하였으며, 간장 및 근원경 생장, 엽 수, 바이오매스, 묘목품질지수(SQI), 엽록소 함량 등을 측정하였다. 간장 생장과 바이오매스는 T75가 통계적으로 유의성 있게 가장 높았지만(p ˂ 0.05), 근원경 생장과 엽 수는 처리 간의 통계적인 유의성은 없었다(p > 0.05). 묘목품질지수는 T75가 통계적으로 가장 높게 나타났으며(p ˂ 0.05), 다른 두 처리에 비해 약 45% 이상 높았다. 엽록소 a와 b, a/b 비율, 총 엽록소 함량 모두 T75가 통계적으로 유의성 있게 가장 높았다(p ˂ 0.05). 본 연구 결과로 돈나무는 T75에서 간장 생장, 바이오매스, 묘목품질지수, 엽록소 함량이 가장 높게 나타났으며, 이를 통해 돈나무 묘목 생산체계 구축을 위한 기초자료로 활용될 수 있을 것으로 기대된다.

The hydrogen embrittlement could lead to big damages in bolt/nut, fittings, especially, high pressure valve and high leak-proof valve and so on. Thus, special alloy, for instance, such as Monel and Inconel, is recently used to suppress the problems of hydrogen embrittlement in semiconductor facilities, FCEV(fuel cell electric vehicle) and hydrogen gas stations. The purpose of this study is to investigate the characteristics according to ratio change between drawing and extrusion of Monel material within elastic limit through numerical analysis. As the results, the possibility of plastic deformation in case of drawing was greater than that of extrusion. Consequently, the safety factor related to plastic deformation shows the results depending on the ratio change of force between drawing and extrusion.

With medical use of hemp, many medicinal cultivars were bred worldwide. Propagating cultivar using seed has a high cost. On the other hand, vegetatively propagating cultivar has various merits including short breeding period and uniformity. This study aimed to determine optimal conditions for propagating hemp after cutting, including sterilizing of rooting media, rooting hormone, and mixing ratio of growing media and sand of rooting media. Korean landrace strain of hemp plant was grown in Wagner pot (size: 1/2,000 a) for 60 days. Its branches were cut to 70∼80 mm in length and used for cutting slips. The rooting medium, a horticultural nursery medium, was autoclaved for 3 hours at 120 ℃. The mixing ratio of sand and nursery media was 9:1, 7:3, 5:5, or 3:7 in weight. Cutting slips were coated with rooting hormone (1-naphthylacetamide 0.4%) just before planting. Cutting materials were planted in a tray pot of 72 cells and grown in a walk-in-chamber for 28 days with a temperature of 25 ℃ and an intensity of radiation of 800 μmol/㎡/sec. Seedling rates were 61.1%, 77.8%, and 63.0% for mixing ratios of 1:9, 3:7, and 5:5 of sand mixed with horticultural nursery medium. These seedling rates were significantly higher than a seedling rate of 31.5 % for a mixing ratio of 7:3. Root lengths were 97 mm, 91 mm, and 81 mm for mixing ratios of 1:9, 3:7, and 5:5 of sand mixed with horticultural nursery medium. These root lengths were significantly longer than a root length of 37 mm for a mixing ratio of 7:3. Rooting rates were 81.1 % and 91.2 % for slips coated with rooting hormone and sterilized rooting media, respectively. They were 40.0 % and 18.3 % for slips not coated with rooting hormone or sterilized rooting media, respectively. Thus, for vegetative propagating (cutting) of medicinal hemp, sterilizing of rooting media and coating slips with rooting hormone will be essential to conducting the propagation process.

With the growth of silicon-based semiconductor sensors in the global sensor market, advancements in body motion detection for wearable devices and sustainable health monitoring have accelerated. This has led to a significant attention on various sensors with excellent flexibility and stretchability, such as PDMS, in numerous applications. In this study to adjust the sensitivity of conventional conductive pressure sensors, a porous sponge structure was initially created using a sugar template method. The polymer was prepared with four different ratios (5:1, 10:1, 20:1, 30:1) to achieve varying flexibilities. To ensure conductivity, the sponge was coated using a dip-coating method with a 3wt% CNT solution. The conductive sponges with various ratios were tested for sensitivity, demonstrating characteristics suitable for a wide range of pressure sensing applications.

PURPOSES : The purpose of this study is to identify the causes and expected problems of traffic flow in connection with ground roads that are expected to become stagnant owing to the increase in underground road infrastructure, and to derive methods to solve the problem in the future. METHODS : The basic design of underground roads is similar to that of tunnels. However, there is a point where the slope is large as the entering and exiting sections move underground. The ability of a heavy vehicle to assume a mound may vary depending on the slope. Therefore, in this study, a connection path section with a long slope was constructed using VISSIM, a simulation program, and it was verified whether analysis related to the slope and heavy vehicles in an underground road can be performed in the simulation. Subsequently, an analysis was conducted by setting a scenario and an effect index. In particular, this study analyzes internal delay patterns in the event of an unexpected situation on an underground connection road by performing shock wave analysis to analyze speed reduction according to heavy vehicles and slopes. RESULTS : A correlation between the slope of the underground road and decrease in the average speed according to the increasing rate of heavy vehicles was established. It was also possible to analyze the maximum length and duration of the delay connected to the rear in the event of a delay in the underground road and the shock wave speed transmitted to the rear. The analysis showed that the rate of increase in problems owing to delays ranged from 5% to 20% for the ratio of heavy vehicles. In particular, all effect scales increased significantly at a 9% slope. CONCLUSIONS : This study analyzes the causes of land congestion (slope and heavy vehicle mixing rate), which can be a major problem in underground roads in the future. In the future, by establishing lane-specific speed control strategies and lane control strategies based on this study, it will be necessary to derive solutions such as introducing traffic safety on the underground road by minimizing the shock wave delivered to the rear by providing information on traffic communication conditions inside the underground road to individual vehicles.

As environmental concerns escalate, the increase in recycling of aluminum scrap is notable within the aluminum alloy production sector. Precise control of essential components such as Al, Cu, and Si is crucial in aluminum alloy production. However, recycled metal products comprise various metal components, leading to inherent uncertainty in component concentrations. Thus, meticulous determination of input quantities of recycled metal products is necessary to adjust the composition ratio of components. This study proposes a stable input determination heuristic algorithm considering the uncertainty arising from utilizing recycled metal products. The objective is to minimize total costs while satisfying the desired component ratio in aluminum manufacturing processes. The proposed algorithm is designed to handle increased complexity due to introduced uncertainty. Validation of the proposed heuristic algorithm's effectiveness is conducted by comparing its performance with an algorithm mimicking the input determination method used in the field. The proposed heuristic algorithm demonstrates superior results compared to the field-mimicking algorithm and is anticipated to serve as a useful tool for decision-making in realistic scenarios.

현대 해양 산업은 기술적 발전을 통해 신속한 발전을 이루고 있다. 이러한 발전을 주도하는 주요 기술 중 하나는 데이터 처리 기술이며, 이 중 자연어 처리 기법은 사람의 언어를 기계가 이해하고 처리할 수 있도록 하는 기술이다. 본 연구는 자연어 처리 기법을 통해 해양안전심판원의 재결서를 분석하여 이미 재결이 이루어진 선박 충돌사고의 원인 제공 비율을 학습한 후, 새로운 재결서를 입력 하면 원인 제공 비율을 예측하는 모델을 개발하고자 하였다. 이 모델은 사고 당시 적용되는 항법과 원인 제공 비율에 영향을 주는 핵심 키워드의 가중치를 이용하여 사고의 원인 제공 비율을 계산하는 방식으로 구성하였다. 이 연구는 이러한 방식을 통해 제작한 모델의 정 확도를 분석하고, 모델의 실무 적용 가능성을 검토함과 동시에 충돌사고 재발 방지 및 해양사고 당사자들의 분쟁 해결에 기여할 것으로 기대한다.