• 한국수산과학회지
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• 제51권2호
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• pp.148-156
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• 2018

This study was conducted to evaluate dietary hydrolyzed pig bristle meal (PBM) for juvenile olive flounder Paralichthys olivaceus. In Experiment 1 (EXP-1), six experimental diets were prepared to contain 0, 3, 6, 9, 12 and 15% PBM (designated Con, PBM3, PBM6, PBM9, PBM12 and PBM15, respectively). Triplicate groups of olive flounder (initial body weight, 8.69 g) were fed the diets to apparent satiation for 8 weeks during the optimal water temperature season ($20.5{\pm}2.12^{\circ}C$). All PBM supplemented groups except for PBM3 showed significantly lower growth performance and feed utilization compared to the control group. The protein digestibility of PBM3, PBM6, and PBM9 diets did not significantly differ from that of the control diet. In Experiment 2, 1% mono-calcium phosphate was added into the experimental diets used in Exp-1. Triplicate groups of olive flounder (10.6 g) were fed the diets to apparent satiation for 8 weeks during the low water temperature season ($12.5{\pm}1.12^{\circ}C$). The growth performances and feed utilization of fish fed all diets except for PBM15 diet did not significantly differ from those of the control diet. This study indicates that hydrolyzed PBM can replace fish meal by up to 12% with limiting amino acids and mono-calcium phosphate in diets for juvenile olive flounder.

• 멤브레인
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• 제19권2호
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• pp.157-164
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• 2009

소수성, 고무상 고분자인 polydimethylsiloxane (PDMS) 소재를 대상으로 치밀한 단일막과 복합막을 제조하였으며 이들을 이용한 투과증발법을 통해 바이오부탄올을 농축하는 실험을 수행하였다. 바이오부탄올 회수를 위해 $1{\sim}5wt%$의 부탄올이 함유된 모델 수용액을 대상으로 조업온도$(20{\sim}40^{\circ}C)$와 막두께$(1{\sim}100{\mu}m)$를 변화시키면서 PDMS막의 투과증발 특성을 조사하였다. $100{\mu}m$ 두께 PDMS 단일막의 경우 공급부탄올의 농도가 증가할수록 포집된 부탄올의 농도, 선택도, 투과도가 증가하였다. 이러한 결과는 물보다 부탄올에 대한 PDMS 소재의 친화성과 막 사슬 내의 큰 자유부피(free volume)로 부탄올에 대한 확산저항이 적기 때문에 부탄올에 대한 선택도와 투과도가 높은 것으로 파악되었다. 조업온도를 $20{\sim}40^{\circ}C$로 증가시키며 투과증발특성을 조사한 결과, 온도의 상승에 따라 포집된 부탄올의 농도, 선택도, 투과도 모두 증가하였다. PDMS막의 두께가 $100{\mu}m$에서 $1{\mu}m$로 얇아질수록 포집된 부탄올의 농도와 선택도는 감소하였으며 투과도는 증가하는 경향을 보였다.

• 공업화학
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• 제20권2호
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• pp.186-190
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• 2009

본 연구는 수소제조를 위한 디메틸에테르 수증기 개질반응에 대한 열역학적 특성 분석을 목적으로 한다. 이를 위하여 온도(300~1500 K), 반응물 조성비(Steam/Carbon ratio = 1~7), 압력(1, 5, 10 기압) 등의 다양한 반응조건을 변화시키면서 열역학적 평형조성 및 효율 등을 조사하였다. 주어진 조건하에서 흡열반응인 개질반응과 발열반응인 수성가스 전환반응 및 메탄화반응간 경쟁특성을 확인하였으며, 반응온도 400 K를 지나면서 수소발생이 관찰되어 550 K를 지나면서 급격한 발생량의 증가를 확인하였다. 반응물 가운데 수증기의 비율을 증가시킬 경우 수성가스 전환반응이 촉진되어 일산화탄소 저감 및 수소발생 증가 거동을 나타내었다. 결과적으로 열역학적 효율감소를 최소화 하면서 수소발생량을 극대화 할 수 있는 조건은 반응온도 900 K 및 수증기 대 탄소간 비율이 3.0 이내의 범위에 해당하는 것으로 판단된다.

• Animal Bioscience
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• 제37권1호
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• pp.142-150
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• 2024

Objective: This study was conducted to assess effects of heat stress on growth performance, physiological parameters, and blood profiles of Hanwoo steers during early-fattening period in climate chambers. Methods: Four Hanwoo steers (body weight, 454.3±10.9 kg; age, 14±0.1 month) were allocated into four levels of temperature-humidity index (THI) in a 4×4 Latin square design for 21 days (pre-adaptation, 7 d; heat stress, 7 d; post-adaptation, 7 d) per period. Experimental treatments were assigned according to THI chart based on National Institute Animal Science (NIAS, 2022): Comfort (25.5℃ to 26.5℃, 60%; THI 73 to 75), Mild (28℃ to 29℃, 60%; THI 77 to 79), Moderate (29.5℃ to 30.5℃, 80%; THI 82 to 84), and Severe (31℃ to 32℃, 80%; THI 85 to 86) in separate climatic controlled chambers. Results: The dry matter intake (DMI) of the formula feed was lower in Severe compared to Mild and Comfort (p<0.05). The DMI of rice straw was the lowest in Severe and lower in Moderate than Comfort and Mild (p<0.05). Both average daily gain and feed conversion ratio of Severe and Moderate were lower than those of Mild and Comfort (p<0.05). Water intake was the highest in Severe and lower in Moderate compared with Comfort and Mild (p<0.05). Heart rate and rectal temperature increased as THI level increased (p<0.05). Glucose was the lowest in Severe and lower in Moderate compared to Comfort (p<0.05). On the contrary, non-esterified fatty acid was the highest in Severe and lower in Moderate compared with Comfort (p<0.05). Blood urea nitrogen of Moderate and Severe were higher than those of Comfort and Mild (p<0.05). Cortisol increased as THI increased (p<0.05). Conclusion: This study demonstrated the negative effects of heat stress on the performance and physiological responses of Hanwoo steers during the early-fattening period. In addition, it is judged that the THI chart for Hanwoo steers of National Institute of Animal Science (2022) was properly calculated.

• Membrane and Water Treatment
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• 제8권3호
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• pp.293-310
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• 2017

An ultrasonic assisting vacuum membrane distillation (VMD) system was designed to promote the heat and mass transfer in membrane distillation (MD) process. Both the effects of operating conditions and ultrasonic parameters to permeation flux in this process were investigated; the heat and mass transfer mechanism was also being discussed in this paper. The results showed that the performance of VMD process was improved significantly by ultrasonic assisting. The permeation flux was boosted at a certain feed solution temperature, pressure at permeate side and feed solution velocity whether or not to PP and PTFE. The results also indicated that ultrasonic power and frequency also was the key factor affecting the mass and transfer efficiencies. The feed side transfer coefficient ($K_f$), corresponding to ultrasonic power ($K_f=4.406-0.026{\times}P+7.824{\times}10^{-5}{\times}P^2$) and ultrasonic frequency ($K_f=0.941+0.598{\times}f-0.012{\times}f^2+6.283{\times}10^{-5}f^3$), was obtained and employed in the modeling of ultrasonic assisting VMD process. The modeling results showed that the calculated value of $K_f$ aligned with experimental results well. Both variations of temperature polarization coefficient (TPC) and concentration polarization coefficient (CPC) were studied based on the obtained data. The results showed that both TPC and CPC were improved obviously by the ultrasonic parameters.

• Asian-Australasian Journal of Animal Sciences
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• 제25권7호
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• pp.1009-1014
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• 2012

Environmental stress boosts the levels of stress hormones and accelerates energy expenditure which subsequently imbalance the body's homeostasis. L-ascorbic acid (L-AA) has been recognized to mitigate the negative impact of environmental stress on production performances in birds. The present investigation was carried out to elucidate the effect of different dietary levels of L-AA on production performance, egg quality traits and fertility in Japanese quail at low ambient temperature. Sixty matured females (15 wks) were equally divided into three groups (20/group) based on the different dietary levels of L-AA (0, 250 and 500 ppm) and coupled with an equal number of males (1:1) obtained from the same hatch. They were managed in uniform husbandry conditions without restriction of feed and water at 14 h photo-schedule. Except for feed efficiency, body weight change, feed consumption and hen-day egg production were recorded highest in 500 ppm L-AA supplemented groups. Among the all egg quality traits studied, only specific gravity, shell weight and thickness differed significantly (p<0.05) in the present study. Fertility was improved significantly ($p{\leq}0.01$) to a dose dependent manner of L-AA. The findings of the present study concluded that dietary L-AA can be a caring management practice at least in part to alleviate the adverse effect of cold induced stress on production performance in Japanese quail.

• 한국양식학회지
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• 제12권3호
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• pp.213-220
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• 1999

This study was performed to investigate the effects of water temperature and stocking density and rotifer density on the mass production of larval red marbled rockfish, Sebastiscus tertius. Total length of the marbled rockfish larva grown in $23^{\circ}C$ of water temperature were 10.80mm, which was the best, while those grown in $29^{\circ}C$ of water temperature were 6.28mm, which was the lowest. The survival rates of red marbled rockfish larvae grown in $20^{\circ}C$ and $23^{\circ}C$ were 24.0% and 18.5%, respectively. However, the survival rate of red marbled rockfish larvae grown in $26^{\circ}C$ was $7^{\circ}C$ and no larvae survived in $29^{\circ}C$. The total length of red marvled rockfish larva stocked at the density of 5 and 10 larvaper liter of water were high, which were 11.52 mm and 11.22 mm, respectively, but those stocked at the density of 30 larva per liter of water were 7.55mm, which was the lowest. The survival rate of red marbled rockfish larva stocked at the density of 2.5 larva per liter of water was 52.0%, which was the best, but the lowest, 18.0% for the red marbled rockfish larva stocked at the density of 30 larva per liter. There was a trend toward decrease in survival rate of red marbled rockfish larva as their stocking density increased. The survival rates of red marbled rockfish larva fed rotifers at the density of 10 and 5 individuals per ml were high, 48.5% and 48.0%, and their total lengths were 11.92 and 11.89mm, respectively, which grew relatively fast. The survival rate and the total length of red marbled rockfish larva fed rotifers at the density of 30 individuals per ml were the lowest, which were 8.40mm and 21.5%, respectively. Also, red marbled rockfish larva fed rotifers at the density of more than 20 individuals per ml achieved poor survival and growth. These results indicated that the proper conditions for the mass production of larval red marbled rockfish were $23^{\circ}C$ of water temperature, fish larva stocking density of 5 to 10 larva per liter of water and rotifers density of 5 to 10 individuals per ml as live feed.

• Membrane and Water Treatment
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• 제9권1호
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• pp.53-62
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• 2018

In this study, vacuum membrane distillation (VMD) was used to treat high-salinity wastewater (concentration about 17%) discharged by chlor-alkali plant after resin regeneration. The feasibility of VMD for the treatment of real saline wastewater by using Polyvinylidene fluoride (PVDF) microporous plate membrane with a pore diameter of $0.2{\mu}m$ was investigated. The effects of critical operating parameters such as feed temperature, velocity, vacuum degree and concentration on the permeate water flux were analyzed. Numerical simulation was used to predict the flux and the obtained results were in good agreement with the experimental data. The results showed that an increase in the operating conditions could greatly promote the permeate water flux which in turn decreased with an increase in the concentration. When the concentration varied from 17 to 25%, the permeate water flux dropped marginally with time indicating that the concentration was not sensitive to the decrease in permeate water flux. The permeate water flux decreased sharply until zero due to the membrane fouling resistance as the concentration varied from 25 to 26%. However, the conductivity of the produced water was well maintained and the average value was measured to be $4.98{\mu}s/cm$. Furthermore, a salt rejection of more than 99.99% was achieved. Overall, the outcome of this investigation clearly indicates that VMD has the potential for treating high-salinity wastewater.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.644-651
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on water quality such as turbidity, temperature, pH and alkalinity. However, the process of chemical reaction to improve water quality (e.g., turbidity) by chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts using Jar-test data. In this paper, a systematic control strategy is proposed to derive the optimum dosage of coagulant, PAC(Polymerized Aluminium Chloride), using Jar-test results. A neural network model is developed for coagulant dosing and purifying process by means of six input variables (turbidity, temperature, pH, alkalinity of raw water, PAC feed rate, turbidity in flocculation) and one output variable, while considering the relationships to the reaction of coagulation and flocculation. The model is utilized to derive the optimum coagulant dosage (in the sense of minimizing turbidity of water in flocculator). The ability of the proposed control scheme validated through the field test has proved to be of considerable practical value.

• Asian-Australasian Journal of Animal Sciences
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• 제17권2호
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• pp.244-249
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• 2004

The effects of supplemental betaine ($Betafin^{(R)}$) in the drinking water (50 g/kg) (WB) or feed (100 g/kg) (FB) were investigated on male broiler chickens ($Cobb{\times}Cobb$) exposed to 4 h episodes of heat stress at $34{\pm}1^{\circ}C$ on day (d) 35 and $36{\pm}1^{\circ}C$ from d 36 to 41. Prior to (d 1 to 34) and following heat exposure (d 35 to 41), betaine supplementation had no significant effect on body weight, total feed intake and cumulative feed conversion ratios of broilers. The total water intake of WB chicks was lower compared to controls. Prior to heat exposure, there was no difference in percentage of mortality among the three dietary groups. Following the heat challenge period, although higher percentage of control chicks succumbed to the heat challenge as compared to those of WB, it was not significantly different. The WB and FB chicks were less hyperthermic than controls in response to the heat challenge. Irrespective of treatment groups, the heat treatment resulted in a marked elevation in heterophil/lymphocyte ratios (HLR). The WB birds, however, had smaller increase in HLR than those of controls during heat exposure. Antibody production against Newcastle disease vaccine on day 35 was not affected by betaine supplementation. On d 42, WB birds had higher antibody production than those of FB. It is concluded that the WB treatment, as measured by HLR, antibody production and mortality rate, has advantages over the FB group under heat stress conditions.