PURPOSES : This study aims to provide quantitative profile values for the objective evaluation of concrete surface profile (CSP) grades in concrete structures. The main aims are to quantify the CSP grade required for concrete surface pretreatment and proposing a more suitable CSP grade for structural maintenance. METHODS : Initially, the challenges in measuring concrete surface profiles were outlined by analyzing pretreatment work and profile samples of concrete pavements. Theoretical foundations for quantifying concrete surface roughness were established, and regression models including linear regression, cubic regression, and log regression were selected. Additionally, the interquartile range anomaly removal technique was employed to preprocess the data for regression modeling. RESULTS : Concrete CSP profiles were measured through indoor tests, and the measured data were quantified. Linear regression, cubic regression, and log regression models were applied to each CSP grade for comparative analysis of the results. Furthermore, comparative studies were conducted through adhesion strength tests based on the CSP grade. CONCLUSIONS : Our results are expected to establish objective standards for the pretreatment stage of concrete repair and reinforcement. The derived reference values can inform standards for the restoration and reinforcement of concrete structures, thereby contributing to performance improvement. Moreover, our results may serve as primary data for the repair and reinforcement of various concrete structures such as airports, bridges, highways, and buildings.

PURPOSES : The purpose of this study is to provide basic data to improve the service life of asphalt pavement using basalt aggregate in Jeju Island by evaluating the performance of asphalt pavement through analysis of material and structural aspects. METHODS : To evaluate the performance of Jeju Island's asphalt pavement, cracks, permanent deformation, and longitudinal roughness were analyzed for the Aejo-ro road, which has high traffic and frequent premature damage. Cores were collected from Aejo-ro sections in good condition and damaged condition, and the physical properties of each layer were compared and analyzed. In addition, plate cores were collected from two sections with severe damage and the cause of pavement damage was analyzed in detail. RESULTS : About 45% of the collected cores suffered damage such as layer separation and damage to the lower layer. The asphalt content of surface layer in the damaged section was found to be 1.1% lower on average than that in the good condition section, and the mix gradations generally satisfied the standards. The density difference between the cores of each layer was found to be quite large, and the air voids was found to be at a high level. CONCLUSIONS : Test results on the cores showed that, considering the high absorption ratio of basalt aggregate, the asphalt content was generally low, and the high air voids of the pavement was believed to have had a significant impact on damage. High air voids in asphalt pavement can be caused by poor mixture itself, poor construction management, or a combination of the two factors. Additionally, the separation of each layer is believed to be the cause of premature failure of asphalt pavement.

This study used optical and scanning electron microscopy to analyze the surface oxidation phenomenon that accompanies a γ'-precipitate free zone in a directional solidified CM247LC high temperature creep specimen. Surface oxidation occurs on nickel-based superalloy gas turbine blades due to high temperature during use. Among the superalloy components, Al and Cr are greatly affected by diffusion and movement, and Al is a major component of the surface oxidation products. This out-diffusion of Al was accompanied by γ' (Ni3Al) deficiency in the matrix, and formed a γ'-precipitate free zone at the boundary of the surface oxide layer. Among the components of CM247LC, Cr and Al related to surface oxidation consist of 8 % and 5.6 %, respectively. When Al, the main component of the γ' precipitation phase, diffused out to the surface, a high content of Cr was observed in these PFZs. This is because the PFZ is made of a high Cr γ phase. Surface oxidation of DS CM247LC was observed in high temperature creep specimens, and γ'-rafting occurred due to stress applied to the creep specimens. However, the stress states applied to the grip and gauge length of the creep specimen were different, and accordingly, different γ'-rafting patterns were observed. Such surface oxidation and PFZ and γ'-rafting are shown to affect CM247LC creep lifetime. Mapping the microstructure and composition of major components such as Al and Cr and their role in surface oxidation, revealed in this study, will be utilized in the development of alloys to improve creep life.

Recently, halogen lamps for vehicle exterior lamp systems are being replaced by LEDs (Light Emitting Diode) in consideration of miniaturization, power consumption, life, luminance, and eco-friendliness. Due to regulations on the amount of light required, luminance, light uniformity, and glare prevention, it is required to develop a light guide for controlling a light source of an LED lamp for a vehicle. For the development of the light guides, the development of machining technology that can cut micro patterns of hundreds of micrometers scale into surface roughness of tens of nanometers scale must be preceded. In this study, the effect of variations in cutting conditions on surface roughness was analyzed through experiments. The micro patterns was manufactured by cutting into STAVAX material, and the surface of the micro patterns was super-finished using a ball-shaped PCD (polycrystalline diamond) tool without flutes. In experiments, the cutting conditions of the super-finishing process were varied, and the varied cutting conditions were feed rate, radial depth of cut, and spindle speed

생강의 기능성 소재화를 위해 흑생강을 제조함에 있어 숙성 조건 최적화를 위한 숙성 온도(75.0~90.0℃, X1)와 시간(18.0~72.0 hr, X2)을 독립변수로 하고 중심합성계획에 따른 11구간의 조건에서 제조된 흑생강의 이화학적 특성 및 항산화 활성을 측정하였다. 흑생강의 수율은 모든 조건에서 60% 이상이었다. 흑생강의 명도와 황색도, 6-shogaol, 총 페놀 및 플라보노이드 함량은 숙성 온도가 높고 시간이 길어질수록 증가되는 경향이었다. 특히 흑생강의 6-shogaol, 총 페놀 함량 및 항산화 활성은 90℃에서 45 hr 숙성 시 최대값을 보였다. 반응표면분석법에 의한 흑생강의 제조 시 예측된 최적 조건은 89.97℃ 및 21.60 시간이었으며, 실측값은 예측값의 92.7~101.6%의 범위였다.

The purpose of this study is to optimize the rice starch and rice protein content ratio for the replacement of fish paste in eomuk using a response surface methodology. The experiment was designed based on the independent variables. The rice starch content (X1: 10, 20, 30%) and rice protein content (X2: 1, 3, 5%) were examined, along with the viscosity (Y1), color (Y2: L, Y3: a, Y4: b), and sensory evaluation of the dough (Y5: Color, Y6: Flavor, Y7: Off flavor, Y8: Taste, Y9: Hardness, Y10: Cohesiveness, Y11: Springiness, Y12: Chewiness, Y13: Overall acceptance), with the results being set as dependent variables. The p value of Y1, Y2, Y5, Y7, Y9, Y10, Y11, Y12, and Y13 showed a level of <0.05 excluding Y6 and Y8. R2 value was high at 0.80-0.95 so that these rice starch and rice protein contents were significantly affected in terms of the quality and sensory preference of eomuk; therefore, the optimal conditions of X1 and X2 were 19.99% and 2.91%, respectively. Under these optimal conditions, the predicted values of acceptance were Y5 (5.44), Y7 (5.36), Y9 (5.22), Y10 (5.46), and Y13 (6.11). These results will be the basis for building a method for obtaining a rice material. Also, they are expected to promote rice consumption through the development of processed foods using rice material.

PURPOSES: Investigating road pavement conditions using an investigation vehicle is challenging especially if repeated driving is required on the by-lane, and the traffic in the investigation section is heavy. A technology used to investigate the road pavement conditions is studied herein using image data obtained by drone photography. METHODS : Flight plans were made for the survey areas, and ground control point measurements were performed. The research section was filmed using drones. The acquired image data were modeled using Pix4Dmapper. The images taken by the drones were used to investigate the road pavement cracks. A digital surface model was extracted from the Pix4Dmapper modeling results using the Global Mapper program to investigate plastic deformation and flatness. As regards plastic deformation, the elevation of each point was extracted at intervals of 50 cm and 10 cm in the longitudinal and lateral directions, respectively, for 20 m× 10 m of the entire road. In terms of flatness, the elevation values for each point were extracted at intervals of 5 cm and 10 cm for the wheel path and 20 m for the entire roadway. RESULTS: This study compared drone-captured images, which were consistent, and vehicle scan images and confirmed that the former can detect a large number of cracks on road surfaces. The results showing the difference in the elevation values of the road surface indicate that the section, wherein the plastic deformation occurs throughout the entire road surface, can be identified and evaluated. With regard to flatness, in future studies, the long-directional elevation value of the target segment extracted using Global Mapper is likely to be derived from the International roughness index, which is the international flatness index used in the ProVAL program developed and used by the Federal Highway Administration. CONCLUSIONS : The road pavement status investigation conducted herein by utilizing drone-acquired images showed that repeated driving in a section is not required, and various analyses can be made in a single shot. If technologies, such as artificial intelligence, big data, and Internet of Things, which are the key components of the Fourth Industrial Revolution, are adapted, they can be used to investigate road pavement conditions and inspect completely constructed road lines and major road facilities.

The purpose of this study was to optimize the rice protein extracted using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the high pressure (X1, 0-400 MPa) and processing time (X2, 0-10 minutes). The results of the extraction content (Y1), residue content (Y2), and recovery yield (Y3) were fitted to a response surface methodology model (R2= 0.92, 0.92, and 0.93, respectively). Increasing the pressure and processing time has a positive effect on the extraction content (Y1), residue content (Y2), and recovery yield (Y3). Therefore, these high-pressure conditions (independent variables) can significantly affect the improvement in rice protein extraction efficiency. Thus, the optimal conditions of X1 and X2 were 400 MPa and 10 min., respectively. Under these optimal conditions, the predicted values of Y1, Y2, and Y3 were 62.93, 57.53 mg/g, and 91.76%, respectively.

PURPOSES : This paper is aimed at suggesting a novel approach for determining the pavement condition rating based on the tire-surface friction noise using a machine learning algorithm as a low-end pavement condition monitoring system. METHODS : Vehicle on-board type noise measurement system according to the ISO11819-2, and the K-nearest neighbors with dynamic time warping algorithm were applied. The system and algorithm were empirically tested with a field study. RESULTS : The developed AI- and noise-based pavement condition monitoring system demonstrated significantly positive results with a precision 90.8%, recall 84.8%, and f1-score 86.1%. CONCLUSIONS: We herein confirmed that the acoustic property between the tire and road surface can be used for monitoring pavement conditions. It is believed this finding presented a new paradigm for monitoring pavement conditions based on visual information. However, extensive studies focused on the practical application of this method are required.

본 연구는 피부표면온도가 유효물질 경피 흡수와 피부 상태변화에 미치는 영향을 실험하였다. 열에 강한 나이아신아마이드 10% 에멀젼을 인공피부에 도포하여 경피 흡수 시험을 진행하였고 동일한 에멀젼으로 피부임상시험을 시행하여 온열효과를 확인하였다. 그 결과 피부표면 온도 42℃에서 정상 피부 온 도보다 도포 10분 경과 후 2배, 15분 경과 후 3배의 경피 흡수 효과를 보였다. 피부임상평가에서는 임상대상자 모두 특이한 이상반응을 보이지 않았으며 수분, 유분 항목에서 통계적으로 유의한 효과를 나타냈다. 이상의 결과로 온열은 유효물질 경피 흡수 촉진과 피부상태 개선에 긍정적인 영향을 미치는 것을 확인하였고 이는 온열을 이용한 다양한 뷰티디바이스 개발에 기초자료가 될 것으로 판단된다.

In this study, the characteristics of muscle relaxation were analyzed by the experimental and numerical method. A skin tissue was produced by imitational biological tissue using the agar powder, saline solution and sugar. The tissue was exposed to three types of wavelength-blue visible radiation(410 nm), red visible radiation(635 nm), and infrared ray(830 nm). The temperature results along the depth of tissue were measured according to the variation of light wavelength and irradiation time. The temperature change of the tissue shown up similar pattern regardless of the light wavelength kinds. The wavelength of infrared ray penetrated strongly into tissue between 3.2 mm and 11.4 mm. Also, the temperature change with the irradiation time was small, and the temperature value of the infrared ray was the largest. As a result, the muscle relaxation will occur mainly at the infrared wavelength.