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        검색결과 280

        101.
        2018.05 구독 인증기관·개인회원 무료
        Conventional airport concrete pavement design uses empirical design method presented by FAA but it is not accurate because it does not consider environment load. In case of mechanistic - empirical design method used overseas, it needs to be modified according to domestic conditions. In this paper, a stress regression model considering environmental load and dual tandem gear load is developed as a mechanical - empirical design process and verified by fatigue model calibration. First of all, literature review was conducted on airports using DT gear as a design aircraft among domestic airports, and the physical properties of concrete pavement layers of each airport were identified. In addition, the environmental load is divided into the temperature load and the moisture load, and the temperature load is calculated from the climatic data of the region where the domestic airport is located, and the moisture load is calculated through the drying shrinkage prediction model developed through the previous study. The stresses occurring in concrete slabs under environmental loads and traffic loads were predicted using FEAFAA, which is a finite element analysis program, and factors predicted to affect concrete pavement were selected for the stress regression.As a result of the sensitivity analysis of the selected factors, the joint spacing, slab thickness, gear load, and road bearing capacity coefficient affected the stress behavior of the slab by more than 5% of the reference stress.According to the mechanical design, the finite element analysis was carried out for the consideration of only the traffic load and the environmental load and the traffic load based on the design factors. Based on the analysis results, multiple regression analysis was performed using the statistical analysis program SPSS and the stress regression equation was calculated. Then, the stress model for the environmental load and the traffic load was calculated and the final stress model with each stress model as the independent variable was derived. Using the calculated stress regression model, the stress was calculated and the bending strength of the concrete was divided to calculate the stress - to - strength ratio, and the appropriate fatigue model was selected and the correction was performed by the least squares method. This study was supported by Incheon International Airport Corporation(BEX00625)
        102.
        2018.05 구독 인증기관·개인회원 무료
        In this study, the effect of dry shrinkage of concrete pavement due to seasonal changes was analyzed by comparing the results of finite element analysis with the temperature and strain measurements at Incheon airport pavement. To measure the behavior of slab by environmental condition in site, static strain gauges and thermometers were installed. To predict changes in the properties of concrete slab, experiments were conducted in site as well as in the lab. The considered parameters of FEA were pavement conditions according to seasonal and material properties change. The results of field measurements and the strain by FEA analysis were different in terms of the effects of drying shrinkage. This is due to humidity changes not applied to input values during FEA analysis. In this study, the difference between the results of field measurements and the results of the finite element model analysis was used to identify the drying shrinkage occurring on the concrete slab. Long-term data analysis in the future will enable the analysis of the trends in drying shrinkage in airport concrete pavement. This study was supported by Incheon International Airport Corporation(BEX00625).
        103.
        2018.04 구독 인증기관·개인회원 무료
        Magnetic resonance imaging (MRI) technique has recently been applied in agriculture and food science. It has potential to visualize internal structure of foods in nondestructive way and provides spatial information which could make reconstruct of three-dimension. MRI system also has great advantage for tracking water in beans or seeds. This study intends to analyze the changes of water distribution of coffee beans during water up-taking process. Samples used in the experiment were ‘Robusta’ coffee beans (Vietnam G1, Scr18 polish). A 30mm diameter plastic disposable test tube was used to hold bean during water up-take process. The oil column was placed next to the tube to get and to use as a reference signal. The magnetic resonance imaging system which installed at Institution for Agricultural Machinery & ICT Convergence in Chonbuk National University was used to obtain magnetic resonance (MR) image data sets. 30 images are included in each image data sets with ‘Axial’ image plane direction. In experiment, we used ‘Gradient Echo 3D’ pulse sequence. The water uptake process was performed for 150 minutes and acquired image data sets in every 10 minutes. This study showed some coffee beans which extracted as region of interest (ROI) from each images to study the water uptake process.
        105.
        2018.04 구독 인증기관·개인회원 무료
        최근 강원도에서 생산되기 시작하는 잎새버섯의 수확후배지를 활용하여 산업곤충의 한 종인 장수풍뎅이의 사육가 능성을 알아보고 장수풍뎅이 사육농가의 유충먹이 구입 시 경제적 비용절감 및 버섯재배농가의 부산물활용에 따른 신 소득을 창출하고자 시험을 추진하였다. 잎새버섯 배지는 참나무 85%와 밀기울 15%의 조성으로 이루어져 장수풍뎅이의 사육에는 무리가 없어 보였으며, 실제 유충 2령충을 4개월 사육한 결과 개체중이 21.6g으로 대조배지(참 나무발효톱밥) 개체중 20.2g보다 양호하였으며 폐사율도 낮게 나타났다. 유충의 가능한 사육밀도를 알아보기 위해 일반적으로 제시하는 밀도(75마리/60L)를 기준으로 0.5, 1.5배의 밀도를 사육한 결과 60L용기에 100마리 정도 사육이 가능하였다. 성충의 암수비율에 따른 산란시험에서는 암수비율 동일조건에서 산란수가 많았으며 잎새버섯 수확후배 지에서보다는 참나무 발효톱밥에서 산란이 양호하였다. 또한 산란효과를 높이기 위해 시판젤리에 여러 가지 첨가제를 넣어 시험한 결과 흑설탕을 첨가한 먹이조건에서 산란이 좀 더 양호한 것으로 나타났다.
        106.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        방울토마토의 수경재배 중 붕소+칼슘+규소 및 칼슘+규소의 복합 엽면시비가 수확 후 품질과 MAP 저장 중 저장성에 미치는 영향을 알아보고자 본 연구를 실시하였다. 엽면시비한 방울 토마토(‘Unicorn’)는 반숙 과상태에서 수확하여 산소투과성 필름으로 포장한 5oC, 11oC, 그리고 24oC에서 25일, 15일, 10일간 저장하였다. 붕소+칼슘+규소 복합처리한 방울토마토가 3가지 저장온도 모두에서 호흡과 에틸렌 발생이 억제되어 MAP 저장중 가장 낮은 생체중 감소와 가장 높은 외관상 품질을 보였다. 수확 후 조사한 방울토마토의 경도, 산도, 비타민 C 함량은 붕소+칼슘+규소 복합처리에서 가장 높았으며, 3가지 온도 모두에서 MAP 저장 후에도 모두 높게 유지되었다. 그러나 과피색, 라이코펜 함량과 당도는 수확 후에는 엽면시비 처리로 차이가 없었으나, 3가지 온도 모두 붕소+칼슘+규소 복합처리에서 가장 낮은 수치를 보였다. 이상의 결과로 볼 때 붕소+칼슘+규소 복합처리는 방울토마토의 수확후 생리 작용을 억제하고 경도, 산도, 비타민 C 함량을 높여 저장성을 향상시키는 것으로 판단되었다
        4,000원
        107.
        2017.11 구독 인증기관·개인회원 무료
        Korea is the second largest coffee consuming country in Asia after the Philippines. For modern people, coffee has jumped over a favorite food and grown into a single culture. There are many processing ways to make coffee. In this study, we utilized magnetic resonance imaging(MRI) based on the principles of nuclear magnetic resonance(NMR) and achieved to acquire images with an non-destructive and non-invasive way. The samples we used in the experiment were ‘Robusta’ coffee bean(Congo). Magnetic resonance(MR) image sets were acquired using a MRI system, installed at Institution for Agricultural Machinery & ICT Convergence at Chonbuk National University. From the raw phase(Green Bean stage) to the roasted phase, we obtained MR images from each phase to monitor the internal changes. We divided experiment into 5 stages, starting with ‘Green Bean’ phase to ‘Roasted’ phase. We obtained images every 6 hours during the ‘Fermentation’ phase and every 3 hours during the ‘Dry’ phase. In MRI, we used a gradient echo pulse sequence to scan fast and to take images right after each experiment stage ends. The direction of imaging plane was coronal 30 images with 64 mm x 64 mm field of view(FOV). As MRI uses the magnetic properties of nuclei which especially hydrogen nuclei from water molecules, images could see clearly with sufficient moisture, but in ‘Dry’ phase, images obtained with noise involved. These result suggested that MRI technique was an efficient method to monitor the moisture distribution changes inside the coffee beans.
        117.
        2016.10 구독 인증기관·개인회원 무료
        Soybean peptide (SP) exhibited low intestinal absorption at oral administration due to its fragile structure under gastric digestion. Therefore, we have attempted to encapsulate peptide by cross-linkage interaction between positive charged chitosan (CS) or chitosan oligosaccharide (CSO) and negative charged peptide. The CS (or CSO) with SP nanoparticles were prepared by using ultrasonification technique. The objective of this study was to find the optimal processing method by changing concentration, pH, and homogenizing conditions. We measured physicochemical properties such as particle size, zeta-potential, encapsulation efficiency (EE%), release rate (RR) and antioxidant ability of samples. The results showed that the optimal processing method was using 0.5% (w/v) CSO (diluted by pH 3 Acetic acid buffer) mixed with 0.5% (w/v) SP (diluted by pH 6 buffer) by 9:1 ratio. Afterwards, using high-speed mixer at 12,000 rpm for 3 min, and then passed 2 times through an ultrasonicator (50% power, 3 min). In this way for processing, the particle sizes of CSO/SP nanoparticles were approximately 300 nm, zeta-potential were approximately 45 mV. In addition, the EE% and RR of CS/SP nanoparticles was higher than the CSO/SP nanoparticles. The increase in antioxidant ability of SP was attributed to the affected by CS/CSO microcapsules. In conclusion, this research can befoundation for the manufacturing process of CS/SP nanoparticles, and it was expected that the future application of this nanoparticle in food matrix.
        118.
        2016.10 구독 인증기관·개인회원 무료
        Cryoprotectant is a substance used to protect biological tissue from freezing injury. However, there was few research paper on application of cryoprotectant in food stuff although its benefits was approved from the biological cell tissues. The objective of this study was to investigate the effect of the sugar addition as a cryoprotectant on the properties of frozen soybean sprouts. Before freezing process, the samples were blanched at 100°C for 1 min to observe the influence of blanching treatment. The blanched or non-blanched soybean sprouts was immersed in sugar solution as cryoprotectant, and continuously, the samples were frozen at -18°C for 24 h. Their physicochemical properties such as drip loss, hardness, color and cellular tissue were analyzed after thawing in running water. In our study, the drip loss of blanched sample without sugar was 43%, and comparatively, blanched one with sugar was 20% which was the lowest value among all samples. There was no significant difference of hardness between sample with sugar and without sugar. From our results, it was supposed that sugar can protect the soybean sprouts during freezing process regardless blanching process.
        119.
        2016.10 구독 인증기관·개인회원 무료
        Excessive salt intake in body induces health risks resulting high blood pressure or heart diseases. Therefore, the low salt concentration and sale tasted food is needed by means of the modification of manufacturing process. The purpose of this study was to study the effect of inhomogeneous salt localization in bread to enhance the saltiness encapsulated salt. The 0, 0.5, 1, 1.5, and 2.0% of liposome encapsulated salt (LS) was added into the baking of white pan bread. The final salt concentration was adjusted at 2% by addition of salt. After baking the bread, the moisture content, loaf volume, fermentation rate, color, texture analysis, salt release rate and sensory test were measured. From this study, moisture content has no significant difference between control and treatments (p>0.05), except for 2.0% LS. Lightness of all treatments was higher than control (p<0.05), whereas, there were no significant difference in hardness (p>0.05). From the sensory test, the bread added 2.0% LS was showed the highest value from the salty taste. Moreover, it is related to the highest release rate of salt was represented at 2.0% LS. In conclusion, the salty intensity of bread can be enhanced by the salt localization using encapsulation of salt.
        120.
        2016.10 구독 인증기관·개인회원 무료
        Recently, semi-dried sweet potato is popular as a natural snake for children’s dessert. The drying condition was optimized to obtain high quality of sweet potato by oven drying process. The mashed yellow and chestnut sweet potato was dried using the oven drier at different temperature (50, 60, 70, and 80°C) then evaluated for the moisture content, appearance observation, texture properties, and sugar contents and sensory test in every 2, 6 and 12 hours. During the dehydration and drying process, the ending point of moisture content divided in three zone from 0-2 hour, 4-6 hour and 8-12 hour. The moisture content was dramatically decreased from 0 hour - 8 hour, but after 8 hour there is no significant decrease. Yellow sweet potato dried at 80°C for 6 hours was investigated as good product base on the sensory test, hardness value, and color appearances as compared to chestnut potato.