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점도측정법을 이용한 방사선 조사 건조농산품의 검지 가능성
정형욱(Hyung-Wook Chung),정재영(Jaeyoung Jeong),권중호(Joong-Ho Kwon) 한국식품영양과학회 1999 한국식품영양과학회지 Vol.28 No.5
방사선 조사된 건조채소류, 인삼, 향신료 등을 대상으로 시료의 전분 함량과 점도를 측정함으로써 방사선 조사 여부 확인방법을 연구하였다. 대상 시료 10종의 전분함량은 15.64~60.86% 범위로 전분함량과 점도의 크기는 비례하지 않았다. 양배추, 당근, 청경채, 마늘, 버섯, 파, 고춧가루 등은 감마선 조사선량과 점도의 변화간에 유의성을 보이지 않았으나 건생강(R²=0.9271), 백삼(R²=0.6223) 및 건양파(R²=0.7909)는 유의적인 관계를 나타내었다. 따라서 방사선 조사선량의 증가에 따라 점도가 비례적으로 감소하는 생강과 인삼을 대상으로 조사 여부 판정을 위한 specific parameter를 설정하였다. 생강과 인삼 시료에 대한 비조사구의 specific parameter는 13.31과 13.93이었고, 감마선과 전자선 조사 시료(2.5 kGy, 최저 실용선량)의 specific parameter는 생강이 11.92와 11.15, 인삼이 4.40과 5.10으로 나타났다. 이상의 결과에서 볼 때 생강, 인삼 등 전분질 식품은 방사선 조사선원에 관계없이 specific parameter의 변화가 유의적임이 확인되어 미지시료의 방사선 조사 여부 검지에 활용가능성이 인정되었다. Dried vegetables, white ginseng and spices, which were exposed to gamma and electron-beam irradiation, were used in a detection study by measuring their starch content and viscosity change. The samples tested showed different levels of starch content(15.64~60.86%), which was not directly proportional to the viscosity of the samples. The correlation coefficients between irradiation dose and viscosity change were lower in the samples, such as cabbage, carrot, clean vegetable(Chunggyungchae), garlic, mushroom, green onion, and red pepper, while some higher coefficients were found in ginger(R²=0.9271), white ginseng (R²=0.6223) and onion (R²=0.7909). Thus, dried ginger and white ginseng were selected to be used for a detection of irradiated samples using specific parameters(threshold values). Specific parameter for the nonirradiated ginger and ginseng were 13.31 and 13.93, respectively. On the other hand, gamma and electronbeam irradiated samples at 2.5 kGy, the lowest dose for a commercial purpose, showed decreased values, 11.92 and 11.15 in ginger, and moreover 4.40 and 5.10 in ginseng. It is expected that a proportional decrease in a specific parameter with the absorbed doses will be a potentially useful index for detecting whether starchy foods have been irradiated or not.
응축 열전달계수 예측을 통한 이종 습윤성을 갖는 액막 채널 표면의 최적설계 및 열전달 성능평가
최영현(Younghyun Choi),한태양(Taeyang Han),정재영(Jaeyoung Jeong),이용남(Yongnam Lee),조항진(HangJin Jo) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11
Condensation heat transfer, a heat transfer mechanism utilizing the latent heat, has used in various industrial applications due to its high heat transfer performance. In the case of the dropwise condensation (DWC), the condensate can be quickly removed, so the condensing surface can be exposed to the vapor effectively. This characteristic of DWC is the reason that it has a higher heat transfer coefficient than filmwise condensation (FWC). However, DWC has limitations in use at various applications (e.g. high temperature & pressure) due to the durability issue of the hydrophobic coating layer. To overcome this limitation, at previous study, surface had been developed to enhance heat transfer performance without the hydrophobic coating layer (i.e. water film channeled surface). In this study, prediction of the heat transfer coefficient was carried out to derive the optimal design of this water film channeled surface proposed to increase the heat transfer performance without hydrophobic coating, and heat transfer performance evaluation was performed at pure vapor condition.