본 연구에서는 친환경적이고 경제적인 수용액 환경에서 금속-유기 골격체(metal-organic frameworks, MOF)인 UiO-66을 합성하는 방법을 개선하고, 합성 조건이 UiO-66의 표면적 및 결정성에 미치는 영향을 분석하였다. 합성 실험은 금 속 용액과 리간드 용액의 주입 순서 및 계면활성제(Tween 20)의 첨가 유무를 변화시키며 진행하였다. 그 결과, 리간드 용액 을 금속 용액에 주입하고 계면활성제를 사용하지 않은 경우, 표면적과 결정성이 더 높은 UiO-66을 얻을 수 있었다. SEM 및 XRD 분석 결과, 계면활성제의 첨가는 입자 크기와 결정 구조에 큰 변화를 주지 않았으나, BET 분석 결과 표면적 감소가 확 인되었다. 이는 합성 과정에서 계면활성제가 핵 형성과 결정 성장에 영향을 미칠 수 있음을 시사한다. 본 연구 결과는 수용액 기반 UiO-66 합성법의 최적화, 대규모 제조 공정 및 다양한 산업적 응용에 유용한 정보를 제공할 수 있을 것이다.

This study optimized the gelling agent and rice protein ratio for developing elderly friendly jelly using a response surface methodology. Response surface analysis was conducted with a gelling agent (0.1, 0.2, and 0.3%) and rice protein (3, 6, and 9%) set as independent variables. Increasing the gelling agent and rice protein ratio raised the pH while lowering the total acidity. The sugar content decreased nonlinearly with a higher gelling agent ratio. The lightness (L) and yellowness (b) differed according to the addition ratios of each ingredient, and the hardness peaked at 0.3% gelling agent and 6% rice protein, but excessive rice protein addition led to a decrease in hardness. Response surface analysis indicated an optimal formulation of 0.16% gelling agent and 6.41% rice protein, with all response variables aligning within the predicted ranges, validating the model.

This study focuses on optimizing the uniform pressing process in precision manufacturing, addressing challenges posed by surface roughness and height differences between components. In real-world conditions, such irregularities can lead to non-uniform pressure distribution during pressing, negatively affecting product quality. To mitigate these issues, a buffer protection layer was introduced between the press and components. The optimization process was conducted through finite element analysis (FEA) to determine the ideal material properties, including elastic modulus, Poisson's ratio, and thickness of the buffer layer. Two surface roughness scenarios were examined to assess the impact of surface conditions on pressing uniformity. The results indicate that a higher elastic modulus, Poisson’s ratio, and thicker buffer layers are more effective in achieving uniform pressing, particularly under rougher surface conditions. This study provides a practical solution for improving the precision and reliability of pressing processes, ensuring better product consistency and enhancing overall manufacturing efficiency.

프로바이오틱스 제품에 대한 수요가 지속적으로 증가하 고 있으며, Lactobacillus 균주가 가장 대중적인 프로바이 오틱스로 널리 사용되고 있다. 프로바이오틱스는 기준에 적합한 균수의 확보가 중요하며 제조원가나 시간 등을 낮 추기 위해 배양법의 개발이 필요하므로 Lactobacillus 생 산을 위한 배양 조건이 최적화되었다. 반응표면방법론에 의한 통계적 최적화에서 반응 변수에 영향을 미치는 독립 변수의 최적 조건은 Lactobacillus acidophilus의 경우 22.55 시간(배양시간), 25oC(배양온도), 3.41%(프리바이오틱스 농 도); Lactiplantibacillus plantarum의 경우 24시간, 30.86oC, 2.00%; Lacticaseibacillus rhamnosus의 경우 66.67시간, 35oC, 3.41%이었다. Lactobacillus의 최적 배양조건은 예측 한 결과와 실제 결과가 밀접하게 일치하는 것을 확인하였 다. 이러한 데이터는 수율 높은 Lactobacillus를 생산하는 데 중요한 포인트를 제공할 것이다.

In this study, in order to confirm the machining characteristics of AISI 1020 CD-Bar, cutting was performed after strength measurement, and surface roughness analysis was performed according to cutting conditions. Tensile strength was reduced by about 27.7% compared to AISI 1045 material, and Rockwell hardness HRC was reduced by 46.7%. The surface roughness measurement after cutting was divided into roughing, semi-finishing and finishing turning. In particular, in finishing machining, the best surface roughness was confirmed when the cutting speed was 150m/min and the depth of cut was 0.6mm based on the feed rate of 0.05mm/rev.

Surface free energy is an important parameter in surface and interface properties of fiber reinforced polymer composite. The BET (Brunauer, Emmett, and Teller) surface area and surface energy of the sample can be obtained by Inverse Gas Chromatography (IGC) based on the adsorption principle. In this paper, surface energy of carbon fiber bundle was tested by means of IGC under different conditions to find reliable test parameters. The main parameters involved include length, mass, and packing density of sample, target fractional surface coverage, flow rate, and maximum elution time. It is demonstrated that IGC has the advantages of simple sample preparation, stable test data, high automation, and high sensitivity for carbon fiber. Among all test conditions, packing density and flow rate have the greatest influences on the experimental results. The optimized test parameters are suitable for various kinds of carbon fiber bundles, including polyacrylonitrilebased and pitch-based carbon fibers with different tensile properties and tow sizes. Moreover, IGC can acutely characterize the surface properties of carbon fibers after carbon nanotube modification and heat treatment, which are hard to carry out using contact angle method.

Carbon steel pipes, which are essentially used in the manufacturing industry, are used in various fields due to the advancement of the industry, and a cutting process is essentially applied to pipes manufactured in a nominal size. The cutting process is the most basic and first process used to obtain a material in a desired shape, and it can affect the quality of subsequent processes such as welding or painting, so high-quality cutting surfaces are essential. Therefore, due to the advantage of improving productivity, it is essential to study to secure the appropriate quality of the cutting surface of the plasma cutting process, which is widely used in the industrial field. In this study, the effect of cut surface quality according to process parameters in the plasma cutting process for carbon steel pipe materials was analyzed. The surface roughness was measured to determine the quality of the cut surface, and the relationship between the surface roughness and the process variables was confirmed by selecting the arc current and cutting speed, which are identified as the main factors forming the surface roughness, as process variables.

Phosphate coating is applied to the surface of the round bar material used in the multi-stage cold forging process for the purpose of lubrication. The film characteristics are determined according to the conditions of the phosphate film treatment process. In this study, the film properties according to the phosphate treatment conditions were defined as the coefficient of repeated friction and quantitative analysis was performed. Different friction behaviors were exhibited depending on the film properties, suggesting that optimization of the phosphate film treatment conditions is possible based on this. Finally, as a practical example, friction behavior according to the film characteristics was applied to the automotive engine bolt forming process. As a final conclusion, the need for linkage analysis with phosphating conditions for optimizing the forging process was raised. In addition, it can be seen that damage to the phosphate film should be considered in the process of predicting the limiting life of the die.

고품질의 아가콩 음료개발을 위해 반응표면분석법에 의한 추출조건을 최적화 하였다. 아가콩 의 최적 볶음조건은 250 ℃, 30분으로 설정하였다. 추출시간, 추출온도에 따른 아가콩의 품질지표인 pH, 색도 및 이소플라본 함량은 1% 이내에서의 유의적인 영향을 미치는 것으로 나타났다. 추출온도와 추출시간이 길어질수록 이소플라본 함량은 높은 것으로 나타났다. 반응표면분석의 이소플라본 추출 공정 최적화 결과 추출온도는 99.5 ℃, 추출시간은 1.7 h으로 나타났으며, 이 조건에서 이소플라본의 최적 수 율은 10.63 μg/mL로 예측되었다.

본 연구에서는 전처리 방법별 건조 단호박의 이화학적 특성을 비교 분석하고 반응표면분석법을 이용하여 단호박 말랭이의 최적 건조 조건을 설정하였다. 단호박의 이취 제거와 가공적성을 위한 건열(굽기), 습열(증자), 마이크로웨 이브 처리의 전처리 방법을 비교하고자 호화 점도를 측정 하여 전처리 시간을 설정하였다. 각 전처리 방법별 열풍 건조 전후의 단호박 품질특성을 비교한 결과, 마이크로웨이브 처리에서 가용성 고형분, 과당, 포도당, 자당 함량이 건열과 습열 처리보다 높았고, 수분 함량, 강도 및 경도가 낮게 나타나 마이크로웨이브 처리를 단호박 열풍 건조를 위한 최적의 전처리 방법으로 설정하였고 반응표면분석법을 이용하여 최적의 열풍 건조 조건을 확인하였다. 반응표면분석은 중심합성 계획법으로 실험을 디자인하여 독립변수로서 건조 온도(30, 40, 50oC, X1)와 건조 시간(4, 6, 8 h, X2)을 설정하고, 종속변수로는 건조 단호박의 수분 함량, 수분활성도, 가용성 고형분, 강도, 경도, 과당, 포도당, 자당 함량, 색도(L*, a*, b*)를 측정하여 건조 조건을 최적화하였다. 최적화 변수로는 적합성 결여 검증에서 Pr> F 값이 0.05 이상인 수분 함량, 수분활성도, 가용성 고형분을 최적화 변수로 설정하였으며, 최적화 결과 43oC의 온도와 7.2시간이 최적 건조 조건으로 확인되었고, 예측값과 실험 값을 비교한 결과 90% 이상의 최적 비율을 보였으며, 해당하는 값이 95% 신뢰구간과 예측구간 범위에 들어 실험 디자인과 모델의 적합성 또한 검증되었다.

This study analyzes the internal temperature characteristics of heater module using a numerical method when the constant heat flux and heat flux time are applied to the surface heating element. The horizontal and vertical dimensions of heater module are 100mm, and the height is 5mm. The heat flux is 10,000W/m2, 15,000W/m2, and 20,000W/m2, and heat flux time is 5 seconds, 10 seconds, 15 seconds, 20 seconds, 30 seconds and 50 seconds, respectively. When the heat flux time was 50 seconds, the temperature of the surface heating element rose to 120.5°C, while the skin epidermis temperature rose 1.7°C. As a result, the surface temperature of the surface heating element increased greatly in the horizontal direction, while it increased low in the depth direction. This is because the heat conduction of the surface heating element is transmitted in the X-Y plane direction, and the thermal conductivity of the pet(polyethylene terephthalate) film and insulation sheet under the surface heating element is very low. when the heat flux at the surface heating element is 20,000W/m2, the skin's epidermal temperature rises up to 0.82℃ compared to 10,000W/m2 and 15,000W/m2.

본 연구에서 흰목이버섯의 추출조건별 추출수율과 기능성 성분의 함량을 비교하여 최적 추출조건을 분석하였으며, 모든 분석에서 R²이 0.9331~0.9462로 유의성을 보이는 것을 확인하였다. 각 독립변수에 따른 추출수율과 ergothioneine, β-glucan 성분을 분석한 결과 추출수율은 추출온도와 추출시료농도에 반비례했으며, 추출시간에는 큰 영향이 없었다. Ergothioneine 성분은 온도가 증가할수록 증가하며, 추출시간은 4.33 h가 가장 높았고 시료량에 큰 영향이 없었다. β-glucan 성분은 온도가 증가할수록 감소했으며, 추출시간에 큰 영향이 없었고 시료량이 21.2 mg/mL에서 가장 높았다. 모든 종속변수의 최대 독립변수는 온도 60 o C, 추출시간 4.33 h, 추출시료농도 16.6 mg/mL에서 추출수율 24.9%, ergothioneine 성분함량 66.8 ug/g, β-glucan 성분함량 34.9 g/100 g으로 나타났다.

CNC cutting process has been mainly used for processing metal materials, and wood processing is also changing to machining by CNC machine. But the researches on the CNC machining of wood and its characteristics were rarely carried out. In this study, we analyzed the machined surface according to the cutting conditions such as the cutting direction, spindle speed, feed rate, cutting depth, chip removal in the CNC machining of wood. The consideration of cutting conditions and their effects on the surface finish will provide possibilities for improving the wood machining processes.

PURPOSES: This study develops various models that can estimate the pattern of road surface temperature changes using machine learning methods. METHODS : Both a thermal mapping system and weather forecast information were employed in order to collect data for developing the models. In previous studies, the authors defined road surface temperature data as a response, while vehicular ambient temperature, air temperature, and humidity were considered as predictors. In this research, two additional factors-road type and weather forecasts-were considered for the estimation of the road surface temperature change pattern. Finally, a total of six models for estimating the pattern of road surface temperature changes were developed using the MATLAB program, which provides the classification learner as a machine learning tool. RESULTS: Model 5 was considered the most superior owing to its high accuracy. It was seen that the accuracy of the model could increase when weather forecasts (e.g., Sky Status) were applied. A comparison between Models 4 and 5 showed that the influence of humidity on road surface temperature changes is negligible. CONCLUSIONS: Even though Models 4, 5, and 6 demonstrated the same performance in terms of average absolute error (AAE), Model 5 can be considered the optimal one from the point of view of accuracy.