• Journal of Mechanical Science and Technology
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• v.20 no.3
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• pp.358-365
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• 2006

The hydraulic pump of an Electro-hydrostatic Actuator should be able to quickly feed large volume of oil into hydraulic cylinder in order to reduce the response time. On the other hand, it should be also able to precisely dispense small amount of oil through low-speed operation so that the steady state position control error of the actuator can be accurately compensated. Within the scope of axial piston type hydraulic pumps, this paper is focused on the investigation how the surface treatment of their cylinder barrel with TiN plasma coating can contribute to the reduction of the friction and wear rate of valve plate in the low-speed range with mixed lubrication. The results showed that the friction torque of the valve plate mated with a TiN coated cylinder barrel could be reduced to 22% of that with an uncoated original one when load pressure was 300 bar and rotational speed 100 rpm. It means that the torque efficiency of the test pump was expected to increase more than 1.3% under the same working condition. At the same time, the wear rate of the valve plate could be reduced to $40\sim50%$.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.533-540
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• 2019

Objective: This study evaluated the growth, digestibility and rumen fermentation between goats and sheep fed a fattening diet fortified with linseed oil. Methods: Twelve 3 to 4 months old male goats and sheep were randomly allocated into two dietary treatment groups in a $2(species){\times}2$ (oil levels) factorial experiment. The treatments were: i) goats fed basal diet, ii) goats fed oil-supplemented diet, iii) sheep fed basal diet, and iv) sheep fed oil-supplemented diet. Each treatment group consisted of six animals. Animals in the basal diet group were fed with 30% alfalfa hay and 70% concentrates at a rate equivalent to 4% of their body weight. For the oil treatment group, linseed oil was added at 4% level (w:w) to the concentrate portion of the basal diet. Growth performance of the animals was determined fortnightly. Digestibility study was conducted during the final week of the feeding trial before the animals were slaughtered to obtain rumen fluid for rumen fermentation characteristics study. Results: Sheep had higher (p<0.01) average daily weight gain (ADG) and better feed conversion ratio (FCR) than goats. Oil supplementation did not affect rumen fermentation in both species and improved ADG by about 29% and FCR by about 18% in both goats and sheep. The above enhancement is consistent with the higher dry matter and energy digestibility (p<0.05), as well as organic matter and neutral detergent fiber digestibility (p<0.01) in animals fed oil- supplemented diet. Sheep had higher total volatile fatty acid production and acetic acid proportion compared to goat. Conclusion: The findings of this study suggested that sheep performed better than goats when fed a fattening diet and oil supplementation at the inclusion rate of 4% provides a viable option to significantly enhance growth performance and FCR in fattening sheep and goats.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.1
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• pp.97-107
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• 2013

The aim of this study was to establish relationships between chemical and physical parameters of wheat with performance and digestibilities of feed components in broiler chickens fed on wheat-based diets. Ninety-four wheat samples were selected for inclusion in four bird trials. Birds were housed in individual wire metabolism cages from 7 to 28 d and offered water and feed ad libitum. Dry matter intake (DMI), liveweight gain (LWG) and gain:feed were measured weekly. A balance collection was carried out from 14 to 21 d for determination of apparent metabolizable energy (AME), ME:gain, dry matter retention, oil and neutral detergent fibre (NDF) digestibility. At 28 d the birds were humanely killed, the contents of the jejunum removed for determination of in vivo viscosity and the contents of the ileum removed for determination of ileal dry matter, starch and protein digestibility. When wheat parameters were correlated with bird performance data, it was found that specific weight was not significantly (p>0.05) related to bird performance. Bird DMI, LWG and gain:feed were best correlated (p<0.05) with the rate of starch digestion, although the coefficients of correlation (r) were still low (0.246 to 0.523). A negative relationship (p<0.01) between AME and total (r = -0.432) and soluble (r = -0.304) non starch polysaccharide (NSP) was observed in this study. Thousand grain weight (TG) was positively correlated with DMI (r = 0.299), LWG (r = 0.343) and gain:feed (r = 0.371). When establishing multiple regression relationships, correlation coefficients greater than 0.8 were achieved for DMI, LWG, gain:feed and ileal crude protein digestibility. However, the economics involved in determining the parameters involved in the regressions make the process impractical.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.469-474
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• 2019

Fermentation of palm oil mill effluent (POME) produces biohydrogen in a mixture at a specific set condition. This research was conducted to purify the produced mixed biohydrogen via absorption and membrane techniques. Three different solvents, methyl ethanolamine (MEA), ammonia ($NH_3$) and potassium hydroxide (KOH) solutions, were used in absorption technique. The highest $H_2$ purity was found using 1M MEA solution with 5.0 ml/s feed mixed gas flow rate at 60 minutes absorption time. Meanwhile, the purified biohydrogen using a polysulfone membrane had the highest $H_2$ purity at 2~3 bar operating pressure. Upon testing with proton exchange membrane fuel cell (PEMFC), the highest current and power produced at 100% $H_2$ were 1.66 A and 8.1 W, while the lowest were produced at 50/50 vol% $H_2/CO_2$ (0.32 A and 0.49 W). These results proved that both purification techniques have significant potential for $H_2$ purification efficiency.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.47-58
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• 2005

Rice straw is one of the main renewable energy sources in Korea, and bio-oil is produced from rice straw with a lab. scale plant equipped mainly with a fluidized bed and a char removal system. We investigated how the reaction temperature affected the production of bio-oil and the efficiency of a char removal system. To elucidate how the temperature depended on the production of bio-oil, experiment were conducted between $450^{\circ}C\;and\;600^{\circ}C$ with a feed rate of about 300g/h. The mass balance was established in each experiment, and the produced gas and oil were analyzed with the aid of GCs and a GC-MS system. The char removal system is composed of a cyclone and a hot filter. In the experiments, we observed that the optimum reaction temperature range for the production of bio-oil is between $450^{\circ}C\;and\;500^{\circ}C$.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.1
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• pp.67-73
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• 2016

The application of titanium has been gradually rising because the utilizing ranges for low weight and high strength are rapidly increased by the need for improving the fuel economy in production industries such as the aviation and automotive in recent. The purpose in this study is to investigate the appropriate cutting conditions on the life of flat and round end mills by measuring the maximum cutting temperature relative to the machining time, and calculating the wear rates of cutting tool with the spindle speed and feed rate of vertical machining center as a parameter in the titanium roughing cut machining which is widely used in critical parts of aircraft, cars, etc. When the wetted roughing cut machining of titanium with a soluble cutting oil is conducted by the flat and round end mills, the maximum cutting temperatures for a variety of spindle speed and feed rate are measured at ten-minute intervals during 60 minutes by an infrared thermometer, and the wear rates of cutting tool are calculated by the weight ratios based on tool wear before and after the experiment. It is found that the maximum cutting temperature and the wear rates of cutting tool are raised as the cutting amount per tool edge is increased with the rise of feed rate, in this experimental range, and as the frictional area due to the rise of contacting friction numbers between tool and specimen is increased with the rises of cutting time and spindle speed. In addition, the increasing rate of maximum cutting temperature in the flat and round end mills are the highest for the cutting time from 50 to 60 minutes, and the wear rate of cutting tool in the flat end mill is 1.14 to 1.55 times higher than that in the round end mill for all experimental conditions.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.355-372
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• 2004

In vitro experiments were conducted to determine the formation of fatty acid soaps (FAS) and neutral detergent fiber (NDF) disappearance rate. The substrates were a basal alfalfa hay containing 1) no oil, 2) 10% soybean oil, 3) 10% com oil, on a weight basis. All the substrates were incubated in triplicate for 0, 3, 6, 12, 24 and 48h in each experiment. After the incubation in the first experiment serum bottles (6oml) were analyzed for nonesterified, esterifed and fatty acid soaps contents. The serum bottles (120mI) from the second experiment were analyzed for pH, $NH_3-N$ and VFA concentration, and dry matter and NDF disappearance rate. pH decreased and the concentration of NH3-N increased significantly with longer incubation time (P<0.0001). The disappearance rates of dry matter and NDF significantly varied with feed, incubation time and oils (P<0.05). The molar concentration of total VFA increased and proportion of acetate significantly decreased with incubation time (P<0.0001), but the proportion of propionate significantly increased with longer incubation time (P<0.0001). Addition of oils to diet lowered the ratio of acetate:propionate (P<0.05). The esterified fatty acids (EFA) decreased with increasing incubation time (P<0.0001), and nonesterified fatty acids (NEFA) increased due to lipolysis of EFA, NEFA then reacted with cations to increase formation of FAS. The formation of FAS increased significantly at 48h of incubation time (P<0.0001). Especially, formation of stearic acid soaps was 27.5 and 32.5 folds with soybean oil and com oil supplements, respectively, by 48h of incubation time (P<0.0001). Alfalfa hay had higher cation contents, particularly Ca, which react with NEFA and FAS can be formed with longer incubation time. Saturated fatty acids had a higher proportion of FAS than did unsaturated fatty acids, suggesting that the former may react more extensively with cations. FAS contents increased with increasing chain length of the fatty acids. Since added vegetable oils fonned FAS, it might decrease negative effects on in vitro fermentation characteristics and NDF disappearance rate.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.9
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• pp.1255-1262
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• 2000

A total of 80 pigs ($5.68{\pm}0.61kg$ BW; 21 d of age) were used to evaluate the effect of fat sources in weaned pigs. Pigs were allotted into five treatments based on body weight, in a completely randomized block design. Treatments consisted of diets representing different ratio between soy oil or corn oil and tallow; 1) S100 (soy oil 100%), 2) S75 (soy oil:tallow=75:25), 3) S50 (soy oil:tallow=50:50), 4) C75 (corn oil:tallow=75:25), 5) C50 (corn oil:tallow=50:50). During d 0 to 14, pigs were fed diets containing 3,400 kcal ME, 23% crude protein, 1.65 % lysine and for the period of d 15 to 28, pigs were fed diets supplying 3,400 kcal ME, 20.5% crude protein, 1.355% lysine. For d 0 to 14, a significant differences in ADG and ADFI were observed among treatments, pigs fed animal-vegetable fat blends gained more than pigs fed the S100. As tallow addition was increased from 25% to 50% replacing soy or corn oil, ADG was improved from 6.32% to 28.38%. In phase II (d 15 to 28) period, ADG, ADFI and FCR were not significantly different among treatments. For overall period (d 0 to 28), pigs fed 50% animal:50% vegetable fat blends diets consumed more feed and grew faster than pigs fed control diet and 75% vegetable oil:25% tallow groups, but the differences was not significant among treatments. Apparent DM, CP and fat digestibility were increased with time postweaning for each treatment. There were no differences in digestibilities of total amino acid during overall period. The combination of soy oil or corn oil with tallow produced slightly higher serum triglycerides (TG) and total cholesterol (TC) combination compared with the soy oil alone. In conclusion, tallow:soy (or corn) oil blends diets improved growth rate and the ratio of 50% tallow plus 50% soy (or corn) oil blends diets were favorable for growth and nutrient digestibilities of weaned pigs.

• Korean Journal of Poultry Science
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• v.26 no.3
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• pp.203-211
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• 1999

This study was performed to develop brand egg. Forty-four week-old Isa Brown were randomly assigned to 8 treatments and the number of hens were 300 per each group. Experimental period was about 10 weeks. The 8 treatment were as follows : astarich 2%(A), astarich 5%(B), chitch chitosan 2%(C), omega-3 powder 2%(D), pyrogreen 1%(E), greenpia 0.2%(F), hydrogenated soy oil 3%(G) and commercial layer feed(H). Eggs were collected at day 0, 7, 14, 40 and 70 for egg quality analyses. Laying rate was significantly higher in astarich groups(B, C) than ant other group, showing average of 88% of laying rate. In terms of egg factors, whole egg weight was the heaviest in control in control(A) and the lightest in omega-3 powder group(E), while egg yolk weight was the heaviest in astarich group(H). Haugh unit(HU) was the mean of 70 for all treatments and there were no significant differences among the treatments. Egg yolk color was significantly different among treatments during experimental period whenever yolk color was measured. At the day 7 after feeding of experimental diets, the yolk color of astarich 5% group(C) was darker and that of omega-3 powder group(E) lighter. The value of yolk color in astarich 5%(C) and 2%(B) was 14.2 and 12.5, respectively. But the rest of the groups did not show any differences in yolk color, showing mean of 11.5. In terms of shell thickness, shell tended to become thinner, but there were no defferences among treatments during experimental period. The mean value of shell thickness was 0.390mm. In conclusion, astarich groups may seem to produce the best possible quality of brand egg.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.385-390
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• 1998

An experiment was conducted for 90 days using 9 growing bull calves (initial LW 71.5 kg) to investigate the effect of replacing til oil cake by poultry excreta on growth performance and nutrient utilization. The animals were randomly divided into three groups. The control group A was fed with conventional concentrate mixture containing til oil cake, rice bran, wheat bran, bone meal and common salt and the groups B and C were offered diets in which 50 and 100 percent of til oil cake of diet A were replaced by dried poultry excreta. All the animals were fed urea soaked rice straw ad libitum and concentrate mixture was given at the rate of 10 g per kg LW. Towards the end of growth trial a conventional digestibility trial was conducted. Average daily live weight gain was 216, 211 and 188 g for animals fed diets A, B and C, respectively. Average daily dry matter intake in groups A, B and C was 3.42, 3.37 and 3.30 kg per 100 kg LW, respectively. The daily live weight gain and dry matter intake did not differ significantly (p > 0.05) among the dietary groups. The digestibility coefficient for DM or NFE was almost similar but that for OM, CP, CF and EE was significantly different (p < 0.01) among the dietary groups. TDN percent in diets A, B and C was 57.3 53.3 and 50.8, respectively and the difference was significant (p < 0.01). Animals in all the groups were in a state of positive nitrogen balance. The results indicated that til oil cake can be replaced by dried poultry excreta in bull calf ration.