• Journal of Biosystems Engineering
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• 제16권2호
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• pp.148-158
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• 1991

This study was undertaken to develop the feed rate control system for the head feed thresher by making use of the microprocessor and to evaluate the response of the system to a various threshing conditions. It was verified the performance of the control system through experiments. Control conditions were determined based on the simulation results of control system. The control system set at RH=500rpm, RL=480rpm for the bundle feed was considered optimum to give a high threshing capability and still to stabilize the feeding seed regardless of the bundle size. The control system for the continuous spread feed set at the range of LH=15mm, and LL=12mm gave a high control performance for the feeding mass of 1.1Kg/m and lower tested. In addition, the feed rate proportionality constant should be set lower than one in order to keep the rotational speed of threshing cylinder within the range of 500~520rpm.

• 한국양식학회지
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• 제22권1호
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• pp.1-4
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• 2009

본 연구는 사료급이율이 여름철에 사육된 넙치 성어의 성장 및 체조성에 미치는 영향을 조사하고자 수행되었다. 최초 평균체중 535g의 실험어를 12개 수조(1.8톤)에 15마리씩 사료급이율 별 3반복으로 수용하여, 1일 2회 실험사료를 급이하며 10주간 사육하였다. 사료급이율은 만복(100%), 만복의 90%, 80%, 70%(어체중에 대한 일일 사료섭취율 기준)로 설정하였다. 사육기간 동안의 평균수온은 $19.2{\pm}2.8^{\circ}C$였다. 사육실험 후, 증체율, 일일사료섭취율 및 비만도는 사료급이율에 따라 유의한 차이를 보였으나, 생존률 및 사료효율은 모든 실험구간에 차이가 없었다. 증체율과 어체의 비만도는 일일 사료급이율이 증가함에 따라 증가하였으며, 만복의 90% 급이구는 만복 급이구와 유의한 차이가 없었으나, 80% 및 70% 급이구는 만복 급이구에 비하여 낮은 결과를 보였다. 실험 종료시, 실험어의 등근육과 간의 일반성분은 실험구간에 특별한 변화경향을 보이지 않았다. 본 연구의 증체율 및 비만도 결과로 볼 때, 여름철에 넙치 성어(535-928 g)의 적정 성장 및 비만도 유지를 위해서는 만복의 90%로 사료를 급이 하여도 좋을 것으로 판단된다.

• 한국식품영양과학회지
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• 제33권1호
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• pp.225-228
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• 2004

반응표면분석법(RSM)을 활용하여 유동층과립기의 흡입공기온도, 물의 투입비율, 분무압력 등이 분유의 과립화에 미치는 영향을 분석하였다. 분유의 과립화 수율은 물의 투입 비율에 많은 영향을 받고 있음을 알 수 있었으며, 겉보기밀도 및 다짐 밀도는 분무압력에 크게 영향을 받고 있음을 보여주었다. 분유의 유동층 과립화의 최적조건은 흡입공기온도6$0^{\circ}C$, 물의 투입비율 16 mL/min, 그리고 분무압력 2.1 bar이었으며, 이때 과립화 수율은 94.0%, 겉보기밀도는 0.350 g/㎤, 그리고 다짐밀도는 0.446 g/㎤로 각각 예측되었다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 추계학술발표 개요집
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• pp.3-15
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• 1996

The formation of a thicker hard alloyed layer have been investigated on the surface of aluminum cast alloy (AC2B) by PTA overlaying process with Cr, Cu and Ni motel powders under the condition of overlaying current 125-200A. overlaying speed 150 mm/min and different powder feeding rate 5-20 g/min. In addition the characteristics of hardening and wear resistance of alloyed layer here been examined in relation to the microstructure of alloyed layer. Main results obtained were summarized as follows: 1) There was an optimum overlaying condition to get a good alloyed layer with smooth surface. This good layer became easy to be formed as increasing overlaying current and decreasing powder feeding rate under a constant overlaying speed. 2) Cu powder was the most superior one in metal powders used due to a wide optimum overlaying condition range, uniform hardness distribution of Hv250-350, good oar resistance and freedom from cracking in alloyed layer with fine hyper-eutectic structure. 3) On the contrary, irregular hardness distribution was usually obtained in Cr ar Ni alloyed layers of which hardness was increased as Cr or Ni contents and reached to maximum hardness of about Hv400-850 at about 60wt%cr or 40wt%Ni in alloyed layer. 4) Cracking occurred in Cr or Ni alloyed layers with higher hardness than Hv250-300 at mere than 20-25wt% of Cr or Ni contents in alloyed layer. Porosity was observed in all alloyed layers but decreased by usage of spherical powder with smooth surface.

• 한국수산과학회지
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• 제44권5호
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• pp.490-498
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• 2011

Two consecutive feeding trials investigated the effects of feeding rate and pellet expansion by water-soaking on the growth performance, blood components and histology of olive flounder Paralichthys olivaceus. The first two experiments were carried out to determine the effects of pellet expansion and feeding rate. In the first experiment, growth performance, feed utilization and survival of fish were not significantly affected by pellet expansion for six weeks. There were no significant differences in hematocrit, hemoglobin, aspartate aminotransferase, alanine aminotransferase, glucose and total protein of fish fed the expanded pellet. However, whole-body lipid content of fish in the non-expanded group was significantly higher than that in the expanded group. Histological analysis of the anterior intestine revealed that fish in the expanded group had shorter and smaller mucous folds. These results indicate that pellet expansion had no beneficial effect in terms of growth performance, feed utilization and fish health. In the second experiment, weight gain and feed efficiency were significantly increased as feeding rate increased from 0 to 2.5% body weight per day (BW/d), but there were no significant differences in weight gain or feeding efficiency in fish fed the expanded pellet at ratios of 2.5% BW/d and satiation for three weeks. Plasma aspartate aminotransferase activity of fish fed the expanded pellet at a ratio of 2.5% was significantly lower than that of starved fish. Histological analysis of the anterior intestine revealed that fish in the 0% group had shorter mucous folds. Broken-line regression analysis suggested that the optimum juvenile olive flounder feeding rate was 3.5% BW/d during the low temperature season ($16-17^{\circ}C$).

• 한국수산과학회지
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• 제42권3호
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• pp.262-267
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• 2009

Two 15-week feeding trials were conducted to investigate feeding rate and feeding frequency for growth of sub-adult flounder in suboptimal water temperature ($12^{\circ}C$). In the first experiment, duplicated groups of fish (initial mean weight of 279 g) were fed a extruded pellet once a day at the different feeding rates of 0.1, 0.15, 0.2, 0.3% body weight per day (BW/d), and satiation (0.32% BW/d). Weight gain and feed efficiency were increased significantly (P<0.05) with increase in feeding rates from 0.1 to 0.3% BW/d, but there were no significant differences in weight gain and feed efficiency of fish fed the diet between 0.3% BW/d and to satiation. Crude protein content of dorsal muscle of fish fed the 0.1% BW/d diet was significantly (P<0.05) lower than that of the other groups. In the second experiment, duplicated groups of fish (initial mean weight of 281 g) were fed to apparent satiation with a extruded pellet at three different feeding frequencies (one meal every two days, one meal a day and two meals a day). Weight gain, feed efficiency and condition factor of fish fed one meal every two days were significantly (P<0.05) lower than those of fish fed one meal and two meals a day, but there were no significant differences in weight gain, feed efficiency and condition factor of fish fed between one meal and two meals a day. Based on the results of this study, optimum feeding frequency is one meal a day with satiation feeding for growth and feed efficiency of sub-adult flounder (270-350 g) in suboptimal water temperature ($12^{\circ}C$).

• 한국양식학회지
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• 제18권1호
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• pp.26-30
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• 2005

본 연구는 부상 건조사료와 습사료의 효능을 비교함과 동시에 이들 사료의 적정 공급률(만복 및 제한 공급)을 조사하기 위해 수행되었다 평균 체중 27 g의 넙치를 각 수조마다 500 마리씩 2반복으로 수용하여 부상 건조사료(EP1과 EP2)와 넙치용 분말사료(우성 사료)와 냉동 전갱이를 1:3의 무게 비율(습중량 기준)로 혼합하여 성형한 moist pellet (MP)을 만복 및 만복의 $85\%$로 공급하면서 10주간 사육하였다. 생존율은 모든 실험구에서 $94\%$ 이상이었으며, 증중량은 EP2를 만복 공급한 실험구가 가장 높았지만, EP1을 만복 공급한 실험구와 MP를 만복 및 제한 공급한 실험구들과는 유의한 차이가 없었다(P>0.05). 사료효율은 EPI과 EP2를 제한으로 공급한 실험구가 가장 높은 결과를 보였으며(P<0.05),동일한 사료 공급률에 있어 MP를 공급한 실험구가 EP1과 EP2를 공급한 실험구에 비해 유의적으로 낮은 결과를 보였다(P<0.05). 일일사료섭취율은 만복 및 제한 공급구 각각에서 MP를 공급한 실험구가 EP1 및 EP2을 공급한 실험구보다 유의하게 높았다(P<0.05). 단백질효율은 만복 및 제한 공급에 관계없이 MP를 공급한 실험구가 EPI 및 EP2를 공급한 실험구보다 유의하게 낮았다(P<0.05). 에너지 축적효율은 사료종류 및 공급률에 영향을 받지 않았다(P>0.05). 전어체의 수분, 단백질 및 회분의 함량은 모든 실험구에서 유의적인 차이를 보이지 않았다. 반면에 지질의 함량은 EP2와 MP의 만복 공급구에서 가장 높았고, EP1의 만복 공급구에서 가장 낮은 값을 보였다. 본 실험의 결과로부터, 본 연구에 사용된 EP 사료들은 현재 양식현장에서 사용하고 있는 생사료를 대체할 수 있을 것으로 생각되며, 사료는 만복으로 공급되는 것이 좋을 것으로 판단된다.

• 한국수산과학회지
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• 제49권5호
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• pp.600-606
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• 2016

The effects of feeding frequency on the growth, food consumption, body composition, and hematological response of the Korean rockfish Sebastes schlegelii were investigated for 77 days at ambient water temperatures (17.2-24.5℃) in a sea cage in Tongyeong, Korea. Three replicate groups of fish were hand-fed to satiation with a commercial diet in one of four different feeding frequency trials (one meal every 2 days, and one, two and three meals per day). At the end of the experiment, the mean weight gain, specific growth rate, and daily feed intake of fish fed one and two meals per day were significantly higher than those of fish fed one meal every 2 days or three meals per day. The feed efficiency of the fish fed three meals per day was significantly lower than that of the fish in the other groups. The glucose concentration of fish fed one meal every 2 days was significantly higher than that of the other groups. We conclude that the optimum feeding frequency for improving the growth of Korean rockfish weighing 100-200 g reared in sea cages is one meal per day under our experimental conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1436-1441
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• 2004

Achieving the maximum blasting efficiency with minimum abrasive consumption is a critical concern in surface preparation stage of shipbuilding and offshore industry. Increasing the abrasive flow rate beyond the optimum point results in a major reduction in productivity even though the amount of abrasive used is larger. So, this study is intend to find out the optimum abrasive-to-air mixing ratio which can make a significant improvement in blasting efficiency and remarkably reduce the amount of abrasive used. From the test results, it can be identified that as the abrasive feeding rate is increased linearly, blasting efficiency is increased to a maximum point and then gradually decreased in the form of a bell-shaped.

• Fisheries and Aquatic Sciences
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• 제24권6호
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• pp.219-227
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• 2021

The effects of various feeding ratios on the growth, body composition, and blood chemistry of the juvenile mandarin fish Siniperca scherzeri (initial body weight 9.6 g) were examined in recirculating freshwater system equipped with 21, 300 L tanks at 20 fish per tank. The triplicate groups of seven feeding ratios treatments were prepared: 100% (control), 95%, 90%, 85%, 80%, 75%, and 70% of satiation. The feed amount of control group was determined by supplying with apparent satiation and then the feed amounts of the other six feeding groups were determined based on the feed amount of the control group. Fish were hand-fed with test diet (55.4% crude protein) for 10 weeks. Weight gain (WG) and specific growth rate of fish fed to 100% satiation were not significantly (p > 0.05) different from those of fish fed to ≥ 80% satiation but were significantly higher than those of fish fed to 75% and 70% satiation. Feed efficiency, protein efficiency ratio, and protein retention of 100% satiation were not significantly different from those of 95% and 90% satiation but were significantly (p <0.05) lower than ≤ 85% satiation. Condition factor, hepatosomatic index, and coefficient variation were not significantly (p > 0.05) affected by feeding ratio. Whole body composition and contents of hematocrit, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, glucose, total protein, and high-density lipoprotein cholesterol in blood serum were not significantly (p > 0.05) affected by the feeding ratio; however, content of total cholesterol tended to decrease as the feeding ratio decreased. Using broken-line analysis of WG, it was suggested that the optimum feeding ratio of juvenile mandarin fish, ranging from 9.0 g to 37.0 g, appeared to be 87.7% of satiation without growth inhibition.