Although monitoring of radon has been extensively implemented throughout South Korea, the risk assessment has been mainly limited to indoor environments such as schools, workplaces, and multi-use facilities, and evaluations have normally been performed separately. In this study, the differences in radon exposure according to two groups (< 1 and 1-6 years old) were evaluated considering various indoor and outdoor environments, timeactivity patterns, variations in radon concentrations, and dwelling type (single detached and apartment house) using Monte-Carlo simulation. The distribution and representative values of radon concentration by micro-environments were confirmed through the Anders-Darling test, and a uniform distribution was applied in case of uncertainty. The effective dose ranged from 1.81 ± 1.19 to 2.81 ± 3.02mSv/y. Comparing the levels recommended by EPA, WHO, and ICRP with the value of the 95th percentile of this study, it was found that the results for those dwelling in detached houses exceeded recommended levels. Infants that spend a lot of time in homes with relatively high levels of concentration of radon are assessed to be somewhat more vulnerable to radon exposure.

The physicochemical properties of the emulsions prepared with four different proteins (pea protein isolate, whey protein isolate, soy protein concentrate, and soy protein isolate) were characterized in terms of particle size, rheological property, and freeze-thaw stability, while the feasibility of the protein-stabilized emulsions as a fat replacer was evaluated. Confocal laser scanning microscopic analysis showed that O/W emulsions were successfully prepared with all the proteins; however, the smallest particle size and excellent syneresis were observed in the WPI-stabilized emulsions. The use of WPI-stabilized emulsions as an alternative for shortening up to 50% level did not lead to differences in the muffin batters’ specific gravity and viscoelastic properties. After baking, the substitution of shortening with the WPI emulsions at up to 50% by weight did not significantly affect the muffins’ specific volume and texture characteristics.

In this paper, design of a recumbent bicycle for loading cargo is introduced as an application example of practical engineering. This device consists of a main frame due to the main load, an occupant seat considering the human body structural condition, a steering device(handle), a power transmission device (gear/chain, pedal, and crank), and a braking device (disk brake). In order to design and manufacture of the device, various subjects learned during the school year are reviewed and practiced. In particular, by designing the shape considering the load acting on the recumbent and the structural conditions of the human body, it is possible to understand the detailed mechanical mechanism as well as the understanding for the basic design. Through this case study, students can develop and enhance their creativity and practical skills for related industries by designing and manufacturing a real recumbent bike and, if necessary, industrializing these skills.

Various rheological methods to measure the hardness of instant cooked rice by a texture analyzer were investigated and compared. Specifically, instant white rice samples with a wide range of hardness were subjected to four different rheological tests with disk, cylinder, rod, and cone probe whose results were inter-correlated. All the measurements demonstrated that the hardness of instant rice was reduced with increasing moisture content and showed negatively linear relationships. Out of the four tests applied in this study, the highest coefficient of correlation (R2 = 0.9268) was observed distinctly in the cone probe test, where both compressive and shear forces can be applied to deform individual rice grains. However, the cylinder probe test had the lowest coefficient of correlation (R2 = 0.7247) because it may be ineffective in causing direct deformation of individual rice grains. Furthermore, when the hardness values (N) were converted to stress (Pa), highly linear correlations (R2 ≈ 0.99) were observed between the tests with similar probe geometry and force application.

본 연구에서의 날개 앞전은 날개의 공기역학적인 기능뿐만 아니라 조류 등의 외부의 손상을 줄 수 있는 것으로부터 날개 내부 구성요소를 보호하고 안전한 항공기 운항을 위한 반드시 필요한 구조 요소이다. 복합재 무인기의 날개 경량화를 위한 최적의 제작 모델을 비교․검토하였다. MSC. Patran/Nastran을 이용한 유한요소해석을 통하여 비틀림 하중의 변위 형상을 비교․확인하였으며, 각 모델들의 비틀림 강도 실험을 통하여 적층 유형, 두께 변화 및 형상 적용에 따른 경량화 성능 개선 을 확인하므로써 소형 복합재 무인기 최적의 경량화 날개 앞전스킨의 형태를 제시하였다.

본 연구의 목표는 쌀가루의 물리화학적 특성을 분석하여 쌀면을 제조하는데 있어 최적 품종을 결정하는 것이다. 쌀 면 제조에 사용된 쌀 품종은 아밀로오스 함량이 다른 품종인 밀양 278호, 한아름 2호, 백진주를 사용하였다. 본 연구 에서는 쌀을 건식 제분하여 100-150 mesh 체를 통과한 쌀가루를 쌀면 제조에 이용하였다. 쌀가루의 물리화학적 특성 은 호화특성, thermo-mechanical 방법을 통해 분석하였으며, 쌀가루의 아밀로오스 함량에 따라 호화특성 및 thermomechanical 특성에서 차이를 나타냈다. 품종별 호화 개시 온도는 밀양 278호, 한아름 2호, 백진주 각각 70.0, 62.7, 63.0 ℃이었으며, 고아밀로스 함량을 갖는 쌀가루 품종인 밀양 278호는 높은 호화 온도를 나타내며, 호화 시 점도의 특성 또한 다른 품종과 차이를 보였다. 제조된 쌀면의 특성은 면의 질감분석, 조리손실률, 국물의 탁도, 단면사진을 통해 분 석하였다. 밀양 278호, 한아름, 백진주로 제조한 쌀 건면의 경도는 각각 4.55, 2.24, 1.89 N의 값을 나타내었다. 면을 삶았을 경우에 백진주는 면이 형성되지 않고 잘게 끊어져 면의 질감을 측정을 할 수 없었으며, 밀양 278호와 한아름 2호 쌀면의 Rmax 값은 각각 0.86, 0.46 N을 나타내었다. 밀양 278호 품종의 경우 다른 두 품종에 비해 호화 시 높은 점도를 나타내고, 낮은 조리 손실률 등 제면 가공적성에 적합할 것으로 판단된다.

The noodle market has been worldwide expanding by the rising tide of the convenience food trend and various consumer acceptances. With this trend, a great deal of effort had been made to enhance the quality attributes of instant noodles to satisfy the demand of current consumers. In this presentation, two primary topics related to the quality attributes of noodles are discussed – production of non‐wheat noodles slit from sheeted dough and reduction of noodle cooking times. First, corn proteins were utilized to form a viscoelastic protein network of non‐wheat dough and their rheological and structural properties were characterized to prepare the noodles slit from sheeted dough. The extended β‐sheet alignment imparted high mixing stability to the non‐wheat dough that could be successfully sheeted and slit to noodle strands without gluten. Second, a novel thermal technology based on the modified transient plane source method was applied in order to characterize the cooking property of instant noodles. The porous structure of wheat‐based noodles was also built up to shorten their cooking times. After cooked, the porous‐structured noodles exhibited higher thermal conductivity and lower firmness, possibly indicating the shortened cooking time. 19

본 연구에서는 냉동저장에 따른 제빵용 밀가루 반죽의물리적 특성 변화를 분석하기 위하여, 냉동생지를 제조 후2주간 -20oC에서 냉동 저장하면서 신장특성, 텍스처, 부피,색상 등의 품질 특성을 측정하고 이를 냉동저장을 하지 않은 대조구와 비교하였다. Extensograph를 활용하여 냉동저장한 밀가루 반죽은 신장도와 신장저항도가 증가하였으며 R/E도 증가함을 확인하였다. 냉동생지를 이용하여 빵을제조한 경우 빵의 부피는 감소하고, 이에 따라 경도는 증가하였고 대조구와 비교하여 어두운 표면이 관찰되었다. 이러한 본 연구의 결과는 냉동 저장 반죽을 이용한 제품제조 시 냉동생지의 물리학적 특성을 파악하여 그 품질을 개선 및 보완하는데 필요한 기초 자료로 활용 될 수 있을 것으로 기대된다.

최근 비만의 증가로 식품 산업계에서는 열량이 없거나 적은 원료로 고열량의 원료를 대체하려는 시도를 하고 있다. 본 연구에서는 젤라틴과 한천을 원료로 동일한 경도의 젤을 만들고 이들의 이화학적 특성을 비교하였다. 동일한 경도를 갖는 젤의 제조를 위하여 물 150 g에 정백당 60 g과 각각 젤라틴 12 g, 한천 2 g을 첨가하여 물 50 g 이 증발할 때까지 중탕하여 성형, 냉각한 후 젤을 제조하였다. 경도는 젤라틴과 한천 젤 각각 22.36, 22.80으로 동등하게 제조하였으며, 이 때 응집성, 부착성, 씹힘성 등은 젤라틴 젤이 더 높았다. 제조된 한천 젤과 젤라틴 젤의 pH는 각각 8.17, 7.05였으며, 당도는 각각 12.97, 14.43oBx를 나타내었다. 응력완화를 측정한 결과 5초 후 한천과 젤라틴 젤의 응력은 각각 3.3, 9.5 N 이였으며 각각 5초, 1초 동안에 급격히 응력이 감소된 후 서서히 완화되었으며 응력완화시간은 한천 젤은 2.54초 였고 젤라틴 젤은 측정이 불가능 하였다. 보수력은 한천과 젤라틴 젤이 각각 98.83, 100%였으며 이는 사용된 한천의 농도가 낮기 때문인 것으로 생각된다. 본 연구 결과는 젤라틴 대체 시 경도를 동일하게 하였을 경우 질감을 비롯한 다른 요소들이 어떻게 영향을 주는지를 판단하는데 도움이 될 것으로 사료된다.

Some animals have special sensing functions in order to find foods, home and mates. Instead of passively sensing, they discharge signals and then extract necessary information from the response. More importantly, they utilize the gradients of the sensed signal in order to find the destination or objects. In this paper this special strategy is formulated mathematically, i.e., the perturbation and the correlation based gradient estimation is developed. A stereo sensor system using temperature sensors mounted on motors is developed for verification. The proposed method can estimate the gradient of the measured value accurately. Using this method, the direction in the maximum measured value can be estimated accurately, and the position of the heat source can be estimated from the intersection of the directions estimated from both sensors.

In this study, the KS A ISO Guide 35 was applied to develop analytical standards for heavy metal cadmium using the Korean mussel (Mytilus coruscus) and to evaluate the homogeneity and stability of the sample. Some of the crucial characteristics that reference materials must consist include homogeneity and stability of both intra- and inter-bottles. We tested homogeneity using ANOVA analysis and short-term stability using regression analysis. The variations of cadmium concentrations did not significantly differ between intra- and inter-bottles (F=0.41, p=0.90). For short-term stability verification, cadmium analysis results were not statistically significant as a result of the regression analysis (significance F=0.51, p=0.53). This suggests that we can not dismiss the null hypothesis that there is no significant variation in concentrations of cadmium over time. These results indicated that the cryogenic-milling process has statistically proven the short-term stability for materials from mussels in the chemical analysis of cadmium. Therefore, we propose that the Korean mussel’s reference material developed for the proficiency test could be used as a tool to evaluate reliability and consistency in laboratories.

The National Environmental Specimen Bank (NESB) has set up a plan to develop reference materials in the facility for assuring analytical quality and validating analytical methods for its monitoring samples. Some of the crucial characteristics that reference materials must consist of are homogeneity and stability of both intra and inter-bottles. In this study, we examined the homogeneity and stability of cryogenically-milled muscle samples, from Common Carp (Cyprinus carpio) for total mercury. Homogeneity was tested using ANOVA analysis and regression analysis was used to test short-term stability. The variations of total mercury concentration did not significantly differ between the intra and the inter-bottle (F=0.8, p=0.37). Additionally, relative standard deviation of the total mercury concentration showed low values (2.28%). For the short-term stability test, total mercury variations were not statistically significant as demonstrated by the result of the regression analysis (F ratio = 3.11, p = 0.18). This suggests that the cryogenic-milling process has statistically proven the degree of homogeneity and short-term stability for samples of carp muscles in the chemical analysis for total mercury.

Haptic systems have been widely used for both virtual reality and augmented reality application including game, entertainment, education and medical sectors. Clothing designers and retailers initiated using AR and VR technologies to help the consumers find style with the perfect fit. Most of the developed augmented reality shopping is implemented by overlapping the image of the clothes on the customer so that he/she can find the fit. However, those are only visual information and the customer cannot experience the real size and the stiffness of the clothes. In this paper, we present the haptic upper garment which provides the haptic feedback to the user using cables. By controlling the length of the cable, the size of the clothes is set and by stiffness control, the compliance of the fabric is implemented. The haptic garment is modeled for precise control and the distributed controller architecture is described. With the haptic upper garment, the user’s experience of the virtual clothes is greatly enhanced.

Marine ecosystems are frequently exposed to a variety of chronic and acute pollutants derived from anthropogenic production and consumption activities. Mussels are sessile (can provide location-specific information), medium-sized (have enough tissue matrix for chemical analysis) filter-feeders (show accumulation of pollutant chemicals from seawater). These biological and ecological characteristics make mussels virtually ideal for pollution monitoring. In this study, Korean mussels (Mytilus coruscus) were collected from nine different sites situated along the coasts of the western sea to the eastern sea of Korea in 2017. Total mercury concentration was highest (mean ± standard error, 92.7 ± 3.5 ng/g dry) on Baengnyeongdo Island in the western sea, and the sites in the southern sea showed the lowest mean concentrations (42.3 - 44.5 ng/g dry). These results were discussed in terms of possible pollution sources.