• Journal of the Korean Society for Precision Engineering
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• v.26 no.3
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• pp.103-112
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• 2009

A internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with elliptical and involute shapes, while the inner rotor profile is determined as conjugate to the other. And the integrated system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.120-129
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• 2009

An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobes with elliptical shape, while the inner rotor profile is determined as conjugate to the other. And the integrated system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.88-96
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• 2006

A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. Especially the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of the internal lobe pump which is a particular type of positive displacement pump. The main components of the pump are rotors; usually the outer rotor profile is characterized by lobes with circular shape, while the inner rotor profile is determined as conjugate as the outer rotor profile. For this reason the topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in order to avoid cusp and loop between rotors. And the integrated system which is composed of three main modules has been developed through AutoLISP & Visual Basic and CAD considering various design parameters. It generates automatically an designed model for a general type of a gerotor pump and allows us to calculate two performances indexes commonly used for the study of positive displacement pumps: the flow rate and flow rate irregularity. Results obtained using the system enable the designer and manufacturer of oil pump to be more efficient in this field.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.160-163
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• 2004

A passive lossless turn-on/turn-off snubber network is proposed for the boost PWM converter. Previous AC/DC PFC Boost Converter perceives feed forward signal of output for average current-mode control. Previous Boost Convertor, the Quantity of input current will be decreased by the decrease of output current in light load, and also Power factor comes to be decreased. Also the efficiency of converter will be decreased by the decrease of power factor. The proposed converter presents the good PFC, low line current harmonic distortions and tight output voltage regulations using energy recovery circuit. All of the semiconductor devices in the converter are turned on under exact or near zero voltage switching(ZVS). No additional voltage and current stresses on the main switch and main diode occur. To show the superiority of this converter is verified through the experiment with a 640W, 100kHz prototype converter.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.320-329
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• 2016

Salmonella is one of the most important food-borne zoonotic pathogens, causing acute or chronic digestive diseases such as enteritis. The acute form of enteritis is common in young pigs of 2 - 4 months of age. The main symptoms include high fever ($41-42^{\circ}C$), loss of appetite, and increased mortality within 2 - 4 days of onset of the disease. It is often the cause of increasing mortality, decreasing growth rate and reducing feed efficiency of piglets. In the case of chronic enteritis in pigs, the main symptom is weight loss due to the continuing severe diarrhea. Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Choleraesuis are typical pig adapted serotypes, which cause one of four major syndromes: enteric fever, enterocolitis/diarrhea, bacteremia and chronic asymptomatic carriage. These syndromes cause a huge economic burden to swine industry by reducing production. Therefore, it is necessary that swine industries should strive to decrease Salmonellosis in pigs in order to reduce economic losses. There are several measures, such as vaccination to prevent salmonellosis, that are implemented differently from country to country. For the treatment of Salmonella, ongoing antibiotic treatment is needed. However constant doses of antibiotics can be a problem because of antibiotic resistance. Therefore, the focus should be made more on prevention than treatment. In this review, we addressed the basic information about Salmonella, route of infection, clinical symptoms, and prevention of Salmonellosis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.222-224
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• 1975

Three strains of common carp, i. e. , Israeli carp, red-and-white, and golden strains, were stocked in the same pond, and their growth rates were compared with following results: From August 12 to November 21 in 1975, fingerlings of the three strains of common carp, Cyprinus carpo, each weighing about 0.5 g with total length of 2 to 3 cm, were stocked. The pond had an area of $316m^2$ with a mean water depth of 55cm, and the bottom was covered with a 20 to 30 cm thick layer of silt containing a considerable amount of decaying organic materials. Feed given was prepared with equal amounts of fish meal and polished barley, of which, in addition, $10\%$ green grass and $1\%$ table salt were mixed together when prepared into paste feed using a chopper after boiling the barley. Total protein content of the feed was $34.9\%$ in dry state with $5\%$ moisture content. Total feed given was 30.08 kg calculated in dry state to produce 20.588 kg of the common carp fingerlings, thus the feed coefficient being 1.51. By strains, the harvested Israeli carp ranged 98 to 311g each with a mean weight of $172.69g(100\%)$, red-and-white strain 15 to 318g with mean of $104.1g(60.3\%)$, and the golden strain 30 to 268g with mean of $128.7g(74.6\%)$. During the rearing season mean water temperature was $23.9^{\circ}C$ and the assumed main growth period with the water temperature above $15^{\circ}C$ was, upto the end of October, for 80 days with a mean water temperature of $23.9^{\circ}C$. Taking this main growth period as the basis for growth rate analysis, the mean daily increments, expressed as the attained body weight in times of the starting weight, become 1.075786 times (or the Israeli strain, 1.06901 times for the red-and-white strain, and 1.07185 times for the golden strain.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.75-86
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• 2002

Adequate forage amounts in ruminant animal are necessary for proper ruminal function in dairy cow. This study was carried out to determine the effect of total mixed fermentation feeds made by different green forage crops and grain processings on chemical compositions, RFV (relative feed value) and ruminal characteristics in sheep. The experiment was arranged in a split plot design with 4 replications. The main plot consisted of 6 kinds of green forages (corn, grass, rye, rape, alfalfa and oat) and the sub plots three different grain processings such as non-milling, half milling (7mm mesh over), and regular milling (7mm mesh below). And the different TMFFs (total mixed fermentation feeds) were analyzed for chemical composition and fed to 8 ruminally fistulated sheep for ruminal charactics and palatability. RFV, daily feed intake, acetate/propionate ratio of the rape-TMFFs were higher compared with the other treatment. Ruminal content of VFA (volatile fatty acid) of corn-TMFF was highest as 90.19 mmol% and pH of the feed was lowest as 3.82. But, acetic acid, propionic acid and butyric acid were no difference among treatments. In conclusion, the effect of grain proceeding was not appeared but if consider of only RFV, palatability and dry matter disappearance, grade of TMFF was improved in order of rape-, corn-, alfalfa-, grass-, oat- and rye-TMFF.

• Journal of Animal Environmental Science
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• v.1 no.2
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• pp.137-144
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• 1995

This experiment was conducted to determine the effects of non-climatic environmental factors on growth performances and behavioural patterns of weanling pigs. Three hundred and sixty weanling pigs were contained and carried out with three levels of spaces per pig(0.18, 0.23 and 0.30$m^2$) and three different numbers of pigs per pen(15, 20 and 25 pigs) up to 30kg body weight. Designed by using a 3 $\times$ 3 factorial arrangement(three levels of spaces $\times$ three different numbers of pigs). This experiment investigated the effects of main factors and the relationship between each factors. The result of this experiment were summarized as follows ; 1. The reduction of floor space caused the reduction of feed/gain in the weanling pigs. Pigs responded with the increased feed intake(p<0.01) and with no change in body weight gain. 2. There were no significant differences in the body weight gain and feed/gain in weanling pigs by changing group sizes, but group size affected the feed intake significantly(p<0.01). 3. Space allowance affected the behavioural patterns significantly(p<0.01) of weanling pigs. The reduction of floor space caused the increment of aggressive behaviour and weanling pigs responded with the decreased resting, non aggressive social and play behaviour. 4. There were no significant differences in the resting, eating, aggressive and non aggressive social behaviour in weanling pigs by changing group sizes, but the large group size caused the reduction of play behaviour in the weanling pigs(p<0.01). 5. Therefore we concluded that weanling pigs require 0.23$m^2$ per pig and 20~25 pigs per pen for the better environment condition.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.12
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• pp.1614-1625
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• 2010

Two experiments were conducted to evaluate the use of fish silage prepared from Indian oil sardines, Sardinella longiceps, as partial replacement of soybean meal as a sole source of protein for growing broiler chickens. The main objective of Experiment 1, an ileal digestibility assay, was to assess the nutritional value of fish silage compared with soybean meal for feeding broiler chickens. The two test ingredients, soybean meal and dried fish silage, were incorporated into semi-synthetic diets, as the only component containing protein. The ileal digestibility coefficients of amino acids of fish silage were considerably higher than those of soybean meal (p<0.001). The lower digestibility of amino acids from soybean meal was related to the presence of anti-nutritional factors such as trypsin inhibitors. Fish silage had higher levels of sulphur-containing amino acids than soybean meal. The objective of Experiment 2, a growth study, was to evaluate the effect of feeding fish silage on performance and meat quality characteristics of broiler chickens raised under closed and open-sided housing systems. Four diets containing various levels of fish silage (0, 10, 20 and 30%) were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of Experiment 2, 96 birds were randomly selected and slaughtered to evaluate meat quality characteristics. Housing type had significant effects on feed intake and body weight gain (p<0.01). Birds in the open-sided house consumed 4.7% less amount of feed and gained 10.6% less than their counterparts in a closed house. Birds in both houses fed diets containing 10 and 20% fish silage gained more than birds fed 30% fish silage. The current study produced evidence that fish silage can replace up to 20% of soybean meal in broiler diets without affecting either growth performance or the sensory quality of broiler meat.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1553-1558
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• 2012

This study was conducted to investigate the effects of stocking density or group size on feed intake, daily gain, and carcass characteristics of Hanwoo (Korean indigenous breed) steers reared from 7 months to 31 months of age. Thirty Hanwoo steers were divided into four groups with three replicates each (a total of 12 pens). In each group, one (G1), two (G2), three (G3), and four steers (G4) per pen were allocated as treatments. Pen size was $32.0m^2$, and therefore Hanwoo steers in G1, G2, G3, and G4 were reared under different space allowances, i.e. 32.0, 16.0, 10.6, and $8.0m^2$/steer, respectively. Steers were reared following a conventional beef cattle management method in Korea, and were offered a fixed amount of commercial concentrate with ad libitum forages. Results were subjected to analysis of variance with stocking density as the main effect, and significance was declared at p<0.05. Although total feed intake was not significantly altered, it numerically increased in animals of low stocking density (G1) compared to those subjected to high stocking density treatment (i.e. G4). Feed conversion ratio was higher (p<0.05) in G3 compared to G1 and G2. Animals in G1 (low stocking density) grew faster (p<0.05) than those of high stocking density (G3 and G4). Back fat thickness, meat yield index, and meat yield grade were similar among all levels of stocking density. However, longissimus muscle area was larger in G1 and G2 (p<0.01) compared to G3 and G4, and animals in G3 produced smaller carcasses (p<0.05). Carcass quality traits, including marbling score, meat color, fat color, texture, maturity and meat quality grade, as determined by a group of experts, were not significantly different among the treatments. In conclusion, lower stocking density resulted in increased feed efficiency, daily gain, and carcass weight in Hanwoo steers. However it remains unclear whether such differences are the results of stocking density or group size, or a combination of both. Nonetheless, these results confirm previous studies reporting a negative effect of increased stocking density on animal productivity. Further, animal welfare under an intensive farming system in relation to economical return is discussed.