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공작기계 스핀들용 유도전동기의 용량-속도에 따른 손실 및 발열특성 해석
성기현(Ki-Hyun Seong),조한욱(Han-Wook Cho),황주호(Joo-Ho Hwang),심종엽(Jong-Yeob Shim) 대한전기학회 2013 전기학회논문지 Vol.62 No.12
This paper deals with the power loss and thermal characteristics of induction motor for machine tools according to the rated power and speed. To reduce the fabrication error by thermal strain in rotational machine tools, we calculated the power loss and thermal behavior of induction motors. Firstly, the inverse design of general induction motors for machine tool spindle has been performed. The inverse design results are compared with the torque-speed characteristic curve in motor"s catalog. The power loss are calculated by finite element method(FEM) at rated condition. Secondary, the transient thermal characteristics of induction motors are calculated by equivalent thermal resistance model from Motor-CAD S/W. The inverse design, power loss and thermal behavior calculation for induction motors with various rated power and speed has been performed. Finally, to verify the design and calculation process of induction motor, we implemented the experimental set with 0.4kW 1710rpm class industrial induction motor model. The obtained thermal characteristics of experimental model confirmed that the design and power loss calculation processes are appropriate to the prediction of thermal strain in rotational machine tools.
강지훈 ( Ji Hoon Kang ),박승종 ( Seung Jong Park ),성기현 ( Ki Hyun Seong ),송경빈 ( Kyung Bin Song ) 한국응용생명화학회 2014 Journal of Applied Biological Chemistry (J. Appl. Vol.57 No.4
To maintain the quality of sweet persimmon during storage, the samples were treated with a combination of 50 ppm ClO2 and 0.1% fumaric acid after harvest, packaged with low density polyethylene film, and stored at 1±1oC for 35 days. The combined treatment reduced the populations of total aerobic bacteria, yeast and molds by 1.82 and 2.07 log CFU/g, respectively, compared to the control. During storage, hardness of all samples decreased, but total soluble solids and weight loss were not significantly different among treatments. In addition, high-quality dehydrated sweet persimmon was prepared using red algae extract as a dehydrating agent. The rehydration ratio and vitamin C content of red algae extract-treated sample were greater than those of hot-air dried sample. These results suggest that the combined treatment of ClO2 and fumaric acid can be useful for maintaining microbiological safety of sweet persimmon during storage and dehydration of sweet persimmon slices using red algae extract is an efficient drying method for the preparation of high-quality dehydrated sweet persimmon.
기체투과도가 다른 포장재로 포장한 ‘엘리오트’ 블루베리와 ‘설향’ 딸기의 냉장 저장 중 품질 변화
정승훈(Seung Hun Jung),강지훈(Ji Hoon Kang),박승종(Seung Jong Park),성기현(Ki Hyun Seong),송경빈(Kyung Bin Song) 한국식품영양과학회 2014 한국식품영양과학회지 Vol.43 No.6
블루베리 및 딸기의 품질유지를 위한 MAP의 활용 가능성을 확인하고자 비가열 병합 처리 세척과정을 거친 ‘엘리오트’ 블루베리와 ‘설향’ 딸기 시료를 기체투과도가 다른 polyolefin film(6,000 mL O2/m2·24 hr·atm at 24°C)과 PA/PA/PE film(60 mL O2/m2·24 hr·atm at 24°C)에 각각 포장한 후 4°C에 저장하면서 품질 변화를 측정하였다. 수확 후 블루베리와 딸기에 병합 세척처리를 한 결과, 총 호기성균은 각각 2.50, 1.97 log CFU/g, 효모 및 곰팡이에서는 각각 1.95, 2.18 log CFU/g의 감균 효과를 얻어 우수한 살균 효과를 나타내었다. 또한 PA/PA/PE film 포장에 의한 낮은 기체투과도로 인한 높은 이산화탄소 농도 환경에서 미생물의 생육이 저장 중 억제되는 것을 확인하였고, 중량 감소율에 있어서도 높은 기체투과도를 갖는 polyolefin film으로 포장한 처리구보다 낮은 감소율을 보여, 소포장된 블루베리와 딸기의 경우 기체투과도가 낮은 포장재를 이용하는 것이 효율적인 것으로 나타났다. 따라서 본 연구 결과, 수확 후 블루베리 및 딸기의 적절한 기체 조성을 위한 포장재의 선택은 품질 유지 및 유통기한 증대에 도움을 줄 것으로 판단된다. Blueberries and strawberries are highly perishable and easily contaminated with microorganisms. To maintain the quality of these commodities during refrigerated storage, the effects of two packaging materials as well as passive modified atmosphere packaging on the quality of blueberries and strawberries were investigated. The harvested blueberries and strawberries were first treated with combined non-thermal treatment of aqueous chlorine dioxide and fumaric acid, followed by packaging with polyolefin film (6,000 mL O2/m2?24 hr?atm at 24°C) and polyamide/polyamide/ polyethylene film (PA/PA/PE, 60 mL O2/m2?24 hr?atm at 24°C), respectively. After combined sanitizer treatment, the populations of total aerobic bacteria in blueberries and strawberries were reduced by 2.50 and 1.97 log CFU/g while those of yeast and molds were reduced by 1.95 and 2.18 log CFU/g, respectively, compared with the control. In particular, microbial growth in these samples packed with PA/PA/PE film was reduced during refrigerated storage. In addition, the blueberries and strawberries packed with PA/PA/PE film underwent lower weight loss than those packed with polyolefin film during storage. These results suggest that appropriate packaging with proper gas permeability is necessary to maintain the quality of blueberries and strawberries during refrigerated storage.