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정의엽,심기현,Jung, Eui Yoeb,Sim, Ki Hyeon 한국식품영양학회 2019 韓國食品營養學會誌 Vol.32 No.1
The objective of this study was to reduce the waste rate of onion peel, which has excellent functionalities, and to promote its industrial utilization. The methodology involved preparing beef jerkies using liquid seasonings with 0% (OPE0), 50% (OPE50) and 100% (OPE100) onion peel extract (OPE) of domestically produced onion, respectively; and assessing their antioxidant activities and quality characteristics. As the amount of added OPE increased, the contents of crude protein and crude ash increased, while those of crude fat decreased. As for color values, increase in the amount of added OPE led to increase in L value and b value, but decrease in a value. The measurement of mechanical texture showed that hardness and cohesiveness decreased as the amount of added OPE increased. TBARS (thiobarbituric acid reactive substance) content decreased as the amount of added OPE increased. And the amount of added OPE increased, all the antioxidant activity of beef jerky increased. Acceptability test showed the highest preference for OPE50 with regard to flavor, taste texture and overall acceptability. Quantitative descriptive analysis (QDA) showed that increase in the amount of added OPE led to increase in meat color, salty taste, sweet taste, meat flavor and chewiness and decrease in off-flavor. According to principal component analysis (PCA), OPE50 and OPE100 had high levels of the sensory attributes that increase preference-such as meat color, salty taste, sweet taste, meat flavor and chewiness. Based on such results, it was established that 50% is the optimal mixing ratio of OPE for preparing a beef jerky of high preference that also has excellent quality characteristics and antioxidant activity.
90도 곡관 내부의 유동가속부식을 저감시키기 위한 구조물 삽입에 대한 연구
정의엽(Eui Yeop Jung),최석민(Seok Min Choi),김선호(Seon Ho Kim),김경민(Kyung Min Kim),조형희(Hyung Hee Cho) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
In the HRSG system, pipe components made of carbon steel are exposed to forced flow. The flow accelerated corrosion by forced flow results in wall thinning, and generates pipe thinning. The rate of wall thinning is related to the mass transfer coefficient in the internal surface of pipe. Thus it is necessary to reduce the mass transfer coefficient for prevention of pipe rupture. In the pipe of 90 degree, the maximum mass transfer coefficient is located at the downstream of turning region by dean vortices. This study focused to investigate the reduced dean vortex using A-shape ribs. Numerical analysis was performed to obtain the mass transfer coefficient using commercial code. Flow velocity was 1.5m/s, and working fluid was water. Based on the comparison of the results, the mass transfer coefficient in the pipe of 90 degree with A-shape ribs reduced at the downstream region of turning part compared to that of smooth pipe due to removal dean vortices.
다열 충돌유출 냉각의 Biot 수에 따른 냉각 성능 평가
정의엽(Eui Yeop Jung),김정주(JeongJu Kim),김상제(Sangjae Kim),박철(Chul Park),김용진(YongJin Kim),조형희(Hyung Hee Cho) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
Cooling performance was determined on a film cooled surface with staggered array jet impingement cooling at various Biot numbers. Heat transfer experiments were conducted using infra-red thermography. Conjugated heat transfer was analyzed with the combined effects of conduction through the test plates and convective heat transfer due to the arrayed jet impingement. The angle of the film cooling holes was 35° and that of the jet impingement holes was 90°. The film and jet impingement holes on each plate were arranged in staggered patterns, and the film cooling holes and jet impingement holes were also positioned in a staggered pattern. The distance between jet and film hole plates was fixed. When jet impingement was added to the internal cooling, the averaged total cooling effectiveness was enhanced. At low Biot numbers, meaning that cooling performance dominated over the conduction effect, the temperature distribution became more uniform due to higher conductive heat transfer. The total cooling effectiveness was strongly related to the Biot number of the plate, and comparing the existing 1-D conduction analysis with the experimental results to predict the total cooling effectiveness in an actual gas turbine engine.
정의엽(Eui Yeop Jung),정희윤(Heeyoon Chung),박세진(Sehjin Park),조형희(Hyung Hee Cho) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
In the present study, total cooling effectiveness was obtained by experiment method on a full-coverage film cooling plate. To confirm the conduction effect of film cooling plate, we conducted three experimental cases. These cases used three different conductive materials, which were polycarbonate, Corian, and stainless steel. The test plates had same hole pattern in the three experiment cases. The hole diameter was 5 mm and the angle of film cooling hole was 35 degree. Spacing to hole diameter ratio (p/d) was 3 on the film cooled plate in both the streamwise and spanwise direction. The jet Reynolds number was controlled to 7,000. The detailed temperature distribution on the film cooled surface was measured using the infra-red thermographic technique. Total cooling effectiveness increased with thermal conductivity of film cooling plate. We demonstrated adiabatic film cooling effectiveness for using this research results.