• 한국식품저장유통학회지
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• 제6권1호
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• pp.55-60
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• 1999

A three variables by three level factorial design and response surface methodology were used to determine optimum conditions for osmotic dehydration of banana. The moisture loss, solid gain, weight loss and reduction of moisture content after osmotic dehydration were increased as temperature, sugar concentration and immersion time increased. The effect of concentration was more significant than those of temperature and time on mass transfer. Color difference and titratable acidity were decreased by higher concentration. Sweetness was increased by increasing sugar concentration, temperature, immersion time during osmotic dehydration. The regression models showed a significant lack of fit (p>0.5) and were highly significant with satisfying values of R2. To optimize osmotic dehydration, based on surface response and contour plots, superimposing the individual contour plots for the response variables. the optimum conditions for this process wire 26$^{\circ}C$, 44 $^{\circ}$brix and 2 hrs for moisture content, sweetness and color difference are less than 72%, 24 obrix and 10 degree.

• 동력기계공학회지
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• 제18권4호
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• pp.11-16
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• 2014

Although smoke emitted from ships is not included in IMO(International Maritime Organiztion) regulation yet, it is one of the substance what is polluting mainly the air. Especially, its concentration is very high when an engine is started and a load is rapidly changed. This is caused by unburned fuel what is injected more than necessary quantity after combustion period. It is possible to decrease smoke concentration emitted at starting engine by controlling fuel injection quantity, but it is concerned that time to rated speed must be spent. Then a governor what can reduce the smoke concentration without a loss of time to rated speed is needed. We adopted a electro-hydraulic governor what can control dual fuel start limit function and achieved very low level of smoke concentration without greater the loss of time to rated speed.

• Food Science and Biotechnology
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• 제15권3호
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• pp.474-477
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• 2006

Dynamic rheological properties of commercial 0.8, 1.0, and 1.2% gums [carboxylmethylcellulose (CMC), guar gum, hydroxypropylmethylcellulose (HPMC), tara gum, and xanthan gum], which can be dissolved in cold water, were investigated by small-deformation oscillatory measurements. Magnitudes of storage (G') and loss (G") moduli increased with increasing concentration of gum solutions except for xanthan gum. Guar gum exhibited greatest G' and G" values among all gums except for G' value at 0.8% concentration. Slopes of G' and G" decreased with increasing concentration of gum solutions except for xanthan gum. Tan ${\delta}$ (G"/G') values decreased with increasing concentration of gum solutions except for xanthan gum. Tan ${\delta}$ values of xanthan gum solutions were much lower than those of other gum solutions, indicating that xanthan gum solutions were predominantly more elastic than viscous.

• Asian-Australasian Journal of Animal Sciences
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• 제15권3호
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• pp.406-409
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• 2002

The effect of refeeding with various single essential amino acids on the recovery of plasma insulin-like growth factor-I (IGF-I) concentration in fasted young chickens was examined. Young chickens (29 days of age) were divided into 15 experimental groups. Chickens in one group were fed on the commercial diet ad libitum for 4 days. The remaining 56 chickens in 14 experimental groups were fasted. After 2 days of fasting, 52 chicks in 13 fasted groups were refed with one of the following experimental diets for 2 days. Eleven experimental diets were protein-free diets supplemented with one of 11 essential amino acids (Arg, Gly, His, Ileu, Leu, Met, Phe, Lys, Thr, Trp, Val). The remaining 2 experimental diets were a protein-free diet containing 11 essential amino acids and a protein-free diet not supplemented with amino acids. Birds in the remaining fasted group continued to be fasted for 2 days. Fasting for 2 days markedly reduced plasma IGF-I concentration. When fasted chickens were refed the protein-free diet containing either Gly alone or all essential amino acids, plasma IGF-I concentration was recovered to the level similar to that of fed chickens. Protein-free diet alone, however, failed to restore the reduced IGF-I concentration in plasma. Body weight loss modulated by feeding with protein-free diets supplemented with various single essential amino acids was associated with changes in plasma IGF-I concentrations. We concluded that body weight loss by feeding with a protein-free diet was lower than that of fasted chickens and that body weight loss associated with the decrease in plasma IGF-I concentration was modulated by feeding with protein-free diets containing various single essential amino acids.

• Korean Chemical Engineering Research
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• 제50권4호
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• pp.627-631
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• 2012

휴대용 고분자전해질 연료전지의 수소발생용으로써 $NaBH_4$는 많은 장점을 갖고 있다. 본 연구에서는 $NaBH_4$ 가수분해 반응용 Co-P-B/Cu 촉매의 내구성에 대해 연구하였다. Co-P-B/Cu 촉매의 내구성 미치는 반응 온도, $NaBH_4$ 농도, NaOH 농도, 촉매 소성온도 등의 영향에 대해 실험하였다. 촉매의 내구성은 가수분해 반응 중에 발생하는 gel 형성에 영향을 받았다. 즉 gel 형성에 의해 촉매 손실률이 증가하였다. $NaBH_4$ 농도가 고농도일 때는 $60^{\circ}C$ 이상에서는 gel 형성이 안 되어 촉매 손실률이 낮았다. 그러나 $40^{\circ}C$ 이하에서는 gel이 형성되어 촉매 손실률이 증가했다. $NaBH_4$ 20 wt%, $40^{\circ}C$에서 NaOH 농도증가에 따라 겔이 형성되어 촉매 손실률이 증가함을 보였다. Co-P-B/Cu 촉매의 높은 온도에서 소성은 내구성을 향상시켰지만 촉매 활성을 감소시켰다.

• 한국염색가공학회지
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• 제18권4호
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• pp.37-42
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• 2006

Two kinds of sea-island type polyester ultramicro fibers (fiber fineness : 0.01 and 0.05 denier) were treated with NaOH varying time and concentration. Surface morphology of the treated fibers with alkaline weight loss was observed by SEM. The treated effects were investigated by measuring density, melting temperature, and X-ray diffraction patterns. The surface morphology of the polyester ultramicro fiber was changed by NaOH concentration. Weight loss of 0.01d fiber was much larger than that of 0.05d fiber. Density and crystallinity were increased with weight loss of fiber. After the weight loss had finished, the density and crystallinity were decreased because of attack of island partition of the fiber. A melting temperature$(T_m)$ is $250^{circ}$ at untreated fiber on the whole and in 0.05d fiber the $(T_m)$ is $252^{circ}$ at untreated. In 0.01d fiber the $(T_m)$ was increased with weight loss of fiber.

• 한국염색가공학회지
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• 제10권5호
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• pp.39-47
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• 1998

The purpose of this study was to investigate the effect of alkali treatment on EG solution of polyester/silk union cloth(P/S cloth) . Tensile strength, moisture regain, crease resistance, and reduction ratio of the treated P/S cloth were measured. The results of this study were as follows ： 1) The weight loss of P/S cloth treated with EG solution was three times higher than those of P/S cloth treated with $H_2O$. The weight loss of P/S cloth was increased greatly with increasing concentration of NaOH, temperature, and time. Favorable weight reduction of treating condition could be obtained when lower concentration of NaOH was used with longer time. 2) If it was added $H_2O$ on EG solution, weight loss of polyester increased, while those of silk decreased. In addition, decreasing ratio of tensile strength warp direction (polyester) was lower, while those of weft direction(silk) was higher. 3) Moisture regain of P/S cloth treated with EG solution increased with weight loss up to 10% . Crease resistance of P/S cloth was the highest at weight loss of 10~15%.

• 설비공학논문집
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• 제16권11호
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• pp.1028-1034
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• 2004

Recently, the ice storage system using ice slurry has been used increasingly since it has been introduced where the rapid cooling load change is required. Because it overcomes a decrease of the melting performance and an increase of the thermal resistance on the ice layer in static ice thermal storage system. This study is performed to understand the effects of transporting ice slurry through horizontal, vertical and inclined tubes ($30^{\circ},\;45^{\circ}$). It used propylene glycol-water solution and ice particles (diameter of about 2 mm) in this experiment. The experiments were carried out under various conditions, with concentration of water solution ranging from 0 to $20wt\%$, and velocity of water solution at the entry ranging from 1.5 to 2.5 m/s. The results were as follows: Regarding the angle of inclined tube, the highest pressure loss was measured for vertical tube and the pressure loss for $45^{\circ},\;30^{\circ}$, horizontal straight tubes were lower successively. The lowest pressure loss in these tubes was measured at velocity of $2.0{\sim}2.5m/s$ and concentration of $10wt\%$. The outlet IPF was likewise stable in these ranges.

• The Korean Journal of Ecology
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• 제17권3호
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• pp.311-318
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• 1994

치화화 사막에서 몇 가지 식물 뿌리의 분해율과 분해 과정에 따른 질소함량의 변화를 조사하였다 (1986년 10월 ~ 1990년 4월). 뿌리의 분해는 리그닌 함량과 역상관 관계를 보였다(r=-0.84, n=5, p<0.05). 1년생 광엽초본인 Baileya multiradiata의 분해율이 가장 높았고 다년생 협엽 초본인 Panicum obtusum의 분해율이 가장 낮았다. 지역에 따른 분해율은 playa에서 가장 낮았다. Baileya multiradiata를 제외하고 모두 분해 초기에 질소의 무기화가 있은 다음 질소의 부동화가 나타났다. Baileya multirdiata의 뿌리는 분해 초기부터 질소함량이 계속 증가하는 것으로 나타났다. 다년생 협엽초본 뿌리의 리그닌 함량은 광엽초본 뿌리의 리그닌 함량보다 높았다.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.2047-2053
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• 2020

Single-tube burst tests on hydrogenated Zircaloy-4 nuclear fuel cladding under simulated loss-of-coolant accident are conducted to evaluate the impact of hydrogen on burst parameters. The heating rate and initial pressure are varied from 5 K/s to 150 K/s and 5 bar-80 bar, respectively. The hydrogen concentration in the cladding is in the range of 0-2000 wppm. Burst stress is lower for hydrogenated cladding in α-phase. A significant loss of ductility is observed in α-phase and lower α + β-phase for hydrogenated cladding. However, the burst strain is higher for hydrogenated cladding in β-phase. There is a sigmoidal dependency of rupture area with initial stress and rupture area is larger for hydrogenated cladding. A novel burst stress correlation for hydrogenated Zircaloy-4 cladding has been proposed.