• 한국수산과학회지
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• 제43권4호
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• pp.320-324
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• 2010

We investigated the proper feeding frequency and satiation rate for the growth of red- and white-colored carp fingerlings in a feeding experiment. Triplicate groups of fish averaging 6.3 g were fed diets at four feeding frequencies (1, 2, 3, or 4 meals a day) and two satiation rates (satiation and 80% satiation) for 6 weeks. The survival of the fish was not affected by either the feeding frequency or the satiation rate. The weight gain, feed efficiency, and protein efficiency ratio of fish were affected by the feeding frequency and satiation rate, and increased significantly with both. The feed efficiency and protein efficiency ratio with satiation feeding of fish fed four meals a day did not differ from those of fish fed three meals a day. The daily feed intake was affected by the feeding frequency and satiation rate. The moisture, crude lipid, and ash contents of whole body were affected by the feeding frequency. Moisture and crude lipid contents were affected by feeding satiation. Based on these results, we conclude that the proper feeding frequency and satiation rate for the optimum growth of red- and white-colored carp fingerlings is four meals a day with satiation feeding.

• Asian-Australasian Journal of Animal Sciences
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• 제29권3호
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• pp.384-389
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• 2016

A total of 400, one day-old commercial broiler chicks were divided into five diet groups (negative control, positive control group with 55 ppm Zn-bacitracin, 15 ppm ${\beta}$-glucan, 30 ppm ${\beta}$-glucan, and 60 ppm ${\beta}$-glucan) and fed for six weeks. Ten broilers were allotted to each of 40 floor pens. Eight floor pens were randomly assigned to one of the 5 diets. Each diet was fed to the broilers for 6 weeks with free access to water and diet. The survival rate, growth rate, feed efficiency, and feed conversion rate of the broilers were calculated. At the end of the feeding trial, the birds were slaughtered, breast muscles deboned, and quality parameters of the breast meat during storage were determined. The high level of dietary ${\beta}$-glucan (60 ppm) showed better feed conversion ratio and survival rate than the negative control. The survival rate of 60 ppm ${\beta}$-glucan-treated group was the same as that of the antibiotic-treated group, which showed the highest survival rate among the treatments. There was no significant difference in carcass yield, water holding capacity, pH, color, and 2-thiobarbituric acid reactive substances values of chicken breast meat among the 5 treatment groups. Supplementation of 60 ppm ${\beta}$-glucan to broiler diet improved the survival rate and feed conversion rate of broilers to the same level as 55 ppm Zn-bacitracin group. The result indicated that use of ${\beta}$-glucan (60 ppm) can be a potential alternative to antibiotics to improve the survival and performance of broilers. However, dietary ${\beta}$-glucan showed no effects on the quality parameters of chicken breast meat.

• Asian-Australasian Journal of Animal Sciences
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• 제4권3호
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• pp.293-298
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• 1991

A study was conducted to determine the effect of environmental temperature and level of food intake on plasma concentration of thyroid hormones. Three dairy heifers were used in an experiment which consisted of three levels of chamber temperature (10, 20 and $30^{\circ}C$) and three levels of food intake (100, 75 and 50% of recommended requirements). The analysis showed significant effects of environmental temperature on plasma triiodothyronine concentration, rectal temperature, respiration rate and heart rate but not on heat production. The range of plasma triiodothyronine was 2.51~1.79 ng/ml when the environmental temperature varied from 10 to $30^{\circ}C$. Effects of feed intake level were significant for heart rate and heal production. Heat production decreased from 25.9 to $20.0kJ/kg^{0.75}{\cdot}h$ when the TDN intake decreased from 66.3 to $35.1g/kg^{0.75}{\cdot}d$. There was no interactive effect of environmental temperature and feed intake level. Plasma triiodothyronine concentration decreased under high environmental temperature without any changes in heat production. The effects of environmental temperature and feed intake level on the physiological function of thyroid gland, as indicated by the relative circulating rate of thyroid hormones, were found to be clear.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.1-8
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• 2007

Minimizing the cylinder wear and the consumption rate of cylinder oil in a large two-stroke marine diesel engine is of great economic importance. In Korea, authors first developed a motor-driven cylinder lubricator for a Wartsila Switzerland large two-stroke diesel engine. The characteristic of the developed product is that can control automatically the oil feed rate with a load fluctuation by the motor drive and the offset cam. For manufacturing the reliable and useful products, however, it is necessary to investigate further characteristics and to improve performances as a cylinder lubricator. In this study, the effects of pump motor speed, plunger stroke and cylinder back pressure on oil feed rate, maximum discharge and delivery pressures are experimentally investigated by using the electronically controlled quill injection system and distributer in the developed cylinder lubricator. It is found that the oil feed rates of electronic control and mechanical type quills with the in-cylinder back pressure are differently characterized by the role of accumulator, the viscous resistance of contact area, etc. It can be also shown that the maximum discharge pressure of the electronic control quill is lower than the mechanical type one but the maximum discharge pressure difference of two types decreased as plunger stroke is small, and the maximum delivery pressures of two types increased as plunger stroke, motor speed and back pressure are elevated but the maximum delivery pressure of mechanical type is higher than the one of electronic control type.

• 한국정밀공학회지
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• 제3권3호
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• pp.30-39
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• 1986

The burr worsens the accuracy of a workpiece and decreases a lot of pro- ductivity because it takes so much time and efforts to remove it. In this paper, the height, thickness and size of a drilling burr were derived from the drilling variables of drill diameter, chisel edge angle, web rate =($\Frac{2{\times}\;web\;thickness}{drill\;dia}$) and yielding stress of the workpiece as wel as feed, point angle and helix angle. The theoretical and experimental values of drilling thrust, torque and burr size of the testpiece were analyzed with the method of numerical analysis in a standard drilling condition. The order of choosing the drilling variables for the purpose of controlling the burr size was dealt in this paper with burr forming ratio. The results are as follows: (1) The drill diameter forms 42 percents feed 25 percents point angle 23 percents and web rate, chisel edge angle and gelix angle 5 percents of the partial differential slope of drilling thrust within the usual available ranges of drilling variables. (2) The drill diameter forms 55 percents feed 26 percents web rate 9 percents and chisel edge angle, point angle and helix angle 10 percents of the par- tial differential slope of drilling torque in the usual available ranges of drilling variables. (3) About 70 percents of the burr size can be controlled by feed, 29 percents by web rate in the case of a fixed diameter. It is recommended drilling10 variables to be chosen in the order of feed, web rate, drill diameter, point angle, chisel edge angle and helix angle so as to control the burr size effectively.

• 한국식품영양과학회지
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• 제43권9호
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• pp.1407-1414
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• 2014

쌀가루, 고아밀로오스 전분, 분리대두단백, 설탕 및 소금을 첨가하여 feed 수분함량 19~23%, screw speed 200~400 rpm, feed rate 43.6 kg/hr 조건에서 제조한 쌀 스낵의 이화학적 특성을 분석한 결과는 다음과 같다. 쌀 스낵의 bulk density는 0.06~0.21, apparent density는 0.55~0.65 정도로 나타났고, feed 수분함량이 많을수록, screw 속도가 감소할수록 증가하는 경향을 보였다. 쌀 스낵의 팽화율은 density와는 반대로 feed 수분함량이 낮을수록, screw 속도가 증가할수록 증가하였다. 쌀 스낵의 WAI는 feed 수분함량이 많을수록, screw 속도가 감소할수록 증가한 반면, WSI는 WAI와는 반대의 경향을 나타냈다. 쌀 스낵의 breaking strength는 feed 수분함량이 증가할수록, screw 속도가 감소할수록 증가하였다. 쌀 스낵의 색도 중 L값은 feed 수분함량 19%, 21%에서는 screw 속도가 증가할수록 L값은 낮았으나, feed 수분함량 23%에서는 screw 속도에 따른 유의적인 차이는 없었다. a, b값은 feed 수분함량 19%에서는 screw 속도가 증가함에 따라 높아졌다. 쌀 스낵의 x-ray 회절도는 feed 수분함량이 낮을수록, screw 속도가 높을수록 회절강도가 낮게 나타났고, feed 수분함량 19%, 21%, screw 속도 300 및 400 rpm에서는 V 도형의 특징을 나타냈다. 쌀 스낵의 내부 단면구조는 feed 수분함량이 많을수록, screw 속도가 낮을수록 기공의 생성이 잘 되지 않았고 세포벽이 두껍게 나타났다.

• 멤브레인
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• 제13권4호
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• pp.257-267
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• 2003

반응성 페놀수지 폐액을 처리하기 위해 중공사막 모듈을 이용한 투과증발 막 탈수공정을 연구하였다. 이 공정의 거동을 예측하기 위한 모사모델을 확립하였고 여기에 사용되는 중요 기본 파라메타들을 평판형 막을 사용하여 직접 구하여 사용함으로써 공정모사의 정확성을 얻을 수가 있었다. 이들을 모사치와 중공사 투과증발 막으로 부터 직접 측정한 각 투과특성들을 비교한 결과 서로 잘 일치함을 보여 본 모사모델의 타당성을 입증하였다. 사용된 중공사막은 중공사 안쪽에 활성층이 도포되어 있으며 공급액은 중공사 내부로 공급하였다. 공급액의 막내에서의 흐름속도에 따라 온도분포가 결정되며 이에 따라 막 투과특성이 달라짐을 모사결과로부터 얻을 수가 있었다. 공급액 온도증가는 막을 통한 탈수 투과 속도를 증가시킬 뿐 아니라 반응속도 증가로 인하여 물 생성속도도 증가시킴으로써 공급액 저장조 내의 수분 함량은 이들 상반된 공정들에 의해 결정이 됨을 보였다. 투과압력이 공급액 증기압보다 훨씬 작은 범위에서 증가할 경우 투과추진력인 공급액과 투과부의 투과물 활성도비 감소가 크지 않아 투과특성을 약간 저하시킨다. 그러나 투과압력이 공급액의 증기압에 접근할 경우 활성도비 감소가 현저하게 일어나 투과특성저하가 급격히 일어난다.

• Fisheries and Aquatic Sciences
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• 제27권7호
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• pp.456-467
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• 2024

The objective of this research was to evaluate live-feed effect enriched with Moringa oleifera Leaves upon the rate of metamorphosis and survival from zoea to megalopa of Scylla olivacea larva. The study utilized a live feed consisting of Rotifer (Branchionus plicatilis) and Artemia (Artemia salina) that were supplemented with moringa leaf powder. The enrichment process involved soaking the feed in solutions containing 0, 50, 100, and 150 mg/L of the powder The levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were quantified following the enrichment of the live feed. A further phase involved conducting a feeding study using mud crab larvae. This experiment was conducted with three replications. Feeding mud crab larvae using rotifers starts from stage 1 of zoea to megalopa with a frequency of 2 times a day at a 30 ind/mL density, and using artemia nauplius was from the zoea 2 to megalopa with a frequency of feeding two times a day at a 5 ind/mL density. The results showed that moringa leaf powder could improve EPA and DHA more significant in Rotifer than in Artemia. Combined rotifer and Artemia nauplii enrichment with 100 mg/L of moringa leaf powder positively impacted the proximate mud crab. This treatment also implies that the metamorphosis of mud crab from zoea 1 stage to megalopa become faster than other treatment. The development from zoea 1 to megalopa stage takes around 16 days. The treatment that yielded the highest survival rate (SR) was feeding mud crab larvae with enhanced live feed containing 100 mg/L of moringa leaf powder. This study demonstrated that the incorporation of moringa leaf powder into live feed can enhance the physical condition of mud crab larvae. Furthermore, it suggests that this enrichment can accelerate the progression of developmental stages and enhance the SR of mud crab larvae when reared under controlled settings.

• 해양환경안전학회지
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• 제20권3호
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• pp.304-311
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• 2014

In this study, to apply hydrogen energy to ship engine and to generate effective hydrogen production, we investigated the effects of high temperature $H_2SO_4$ feed rate and cooling water rate to pump parts with fixed frequency needed to reciprocate motion and a simulation was conducted at each condition. In the fixed frequency and cooling water inlet flow rate of 0.5 Hz and 3.9 kg/s, we changed the high temperature $H_2SO_4$ flow rate to 47.46 kg/s (it is 105 % of 45.2 kg/s), 49.72 kg/s (110 %), and 51.98 kg/s (115 %). Also, at 0.5 Hz and 45.2 kg/s of frequency and high temperature $H_2SO_4$ flow, the thermal hydraulic analysis was performed at the condition of 95 % (3.705 kg/s), 90 % (3.51 kg/s), and 85 % (3.315 kg/s). In overall simulation cases, the physical properties of materials are more influential to the temperature increase in the pump part rather than the changes on the feed rate of high temperature $H_2SO_4$ and cooling water. A continuous operation of pump was also capable even if the excess feed of high temperature $H_2SO_4$ of about 15 % or the less feed of cooling water of about 15 % were performed, respectively. When the increasing feed of high temperature $H_2SO_4$ of up to 5 %, 10 %, and 15 % were compared with base flow (45.2 kg/s), the deviation of time period rose to a certain temperature and ranged from 0 to 4.5 s in the same position (same material). In case of cooling water, the deviation of time period rose to a certain temperature and ranged from 0 to 5.9 s according to the decreasing feed changes of cooling water at 5 %, 10 %, and 15 % compared to a base flow (3.9 kg/s). Finally, the additional researches related to the two different materials (Teflon and STS for Pitch and End-plate), which are concerned about the effects of temperature changes to the parts contacting different materials, are needed, and we have a plan to conduct a follow-up study.

• 수산경영론집
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• 제29권1호
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• pp.121-137
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• 1998

This study was conducted to examine the economic evaluation of the newly developed fish meal analog (BAIFA-M) in Korean rockfish feed. A raw fish feed (MP) and two commercially formulated diets (EP) were employed to compare weight gain (WG), feed conversion ratio (FCR) and survival rate (SR) from the sea cage culture system. By using the economic model in the practical sea cage culture system, feed cost, production cost and gross profit per kg production, rate of profit to gross revenue (RPGR), and internal rate of return (IRR) were calculated based upon the results of the experiment and the information of the private aquaculture farm (Young Chang) in Tong young, Korean. IRR criteria is one of the popular economic feasibility analysis methods applicable far aquaculture industry. This is an economic evaluation method to compare the given interest rate or the discount rate with IRR which can be calculated by the difference between the present value of the benefit stream and of the cost stream. The benefits of using EP on WG, FCR, SR, and production cost will be emphasized in this study. Fish averaging 20$\pm$3.6g (Mean$\pm$SD) were randomly distributed in each small cage (6m$\times$6m) as groups of 2,000 fish. By using 3 large size cages (12m$\times$12m), 12 small cages were constructed, and only 9 small cages were employed for three replicates of each diet treatment. To compare with MP diet, two sinking EP diets were designed by our laboratory and produced by the local feed company who wanted to promote these EP diets for the mass cage culture of Korean rockfish in the future. Two EP diets contain white fish meal and/or BAIFA-M as the main animal protein sources : WFM diet, maximum 43% of white fish meal : BAIEA- M diet, 30% of white fish meal nab replaced by BAIFA- M from WFM diet. Results are summarized in Table 1. Fish fed MP diet showed significantly lower SR than does fish fed two EP diets(P<0.05). However, there Were no significant difference on FCR among fish fed three practical diets. Table 1. Average feed conversion ratio (FCR), accumulative average survival rate (SR) and economic evaluation data far three practical diets. As we expected, BAIFA-M diet is more economical than WFM diet as well as MP diet. Feed cost and production cost per kg production from BAIEA - M diet were lower than those from WFM and MP diets. Moreover, gross profit per Kg production, RPGR and IRR from BAIFA- M diet were higher than those from WFM and MP diets. This economic evaluation study clearly indicated that MP diet should be replaced by the commerical formulated EP diets as soon as possible in the near future because MP diet is not economical in the practical sea cage culture system.