• Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.24.1-24.6
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• 2016

We determined the optimum dietary protein level in juvenile barred knifejaw Oplegnathus fasciatus in cages. Five semi-purified isocaloric diets were formulated with white fish meal and casein-based diets to contain 35, 40, 45, 50, and 60 % crude protein (CP). Fish with an initial body weight of $7.1{\pm}0.06g$ ($mean{\pm}SD$) were randomly distributed into 15 net cages (each size: $60cm{\times}40cm{\times}90cm$, $W{\times}L{\times}H$) as groups of 20 fish in triplicates. The fish were fed at apparent satiation level twice a day. After 8 weeks of feeding, the weight gain (WG) of fish fed 45, 50, and 60 % CP diets were significantly higher than those of fish fed 35 and 40 % CP diets. However, there were no significant differences in WG among fish fed 45, 50, and 60 % CP diets. Generally, feed efficiency (FE) and specific growth rate (SGR) showed a similar trend as WG. However, the protein efficiency ratio (PER) was inversely related to dietary protein levels. Energy retention efficiency increased with the increase of dietary protein levels by protein sparing from non-protein energy sources. Blood hematocrit content was not affected by dietary protein levels. However, a significantly lower amount of hemoglobin was found in fish fed 35 % CP than in fish fed 40, 45, 50, and 60 % CP diets. Fish fed 60 % CP showed the lowest survival rate than the fish fed 35, 40, 45, and 50 % CP diets. Broken-line analysis of WG showed the optimum dietary protein level was 45.2 % with 18.8 kJ/g diet for juvenile barred knifejaw. This study has potential implication for the successful cage culture of barred knifejaw.

• Journal of Astronomy and Space Sciences
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• v.21 no.2
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• pp.141-152
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• 2004

Optics fabrication process for precision space optical parts includes bound abrasive grinding, loose abrasive lapping and polishing. The traditional bound abrasive grinding with bronze bond cupped diamond wheel leaves the machine marks of about $20{mu}m$ rms in height and the subsurface damage of about 1 ${mu}m$ rms in height to be removed by subsequent loose abrasive lapping. We explored an efficient quantitative control of precision CNC grinding. The machining parameters such as grain size, work-piece rotation speed and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis. The effectiveness of such grinding prediction models was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment achieved the predictability down to ${pm}20$ nm in height and the surface roughness down to 36 nm in height. This study contributed to improvement of the process efficiency reaching directly the polishing and figuring process without the need for the loose abrasive lapping stage.

• Applied Biological Chemistry
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• v.8
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• pp.21-28
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• 1967

Two experiments with 32 sheep were conducted to study the effects of feeding the same amount of diet per day at different meal frequencies on ration digestibility, energy utilization, rate of gain, body composition and efficiency of gain. The results obtained are as follows: (1) The ingestion by sheep of the same amount of feed per day in 8 meals, 1 meal plus 7 ruminal inflations-deflations, and in 1 meal caused no different effect in the digestibility of the nutrients and energy, or the ME value of the diet. (2) Heat production per unit of metabolic size per unit of dietary intake was markedly lower for sheep ingesting 8 meals or administered 1 meal plus 7 ruminal inflations-deflations per day than for sheep fed 1 meal per day. (3) Body weight gain was significantly greater by sheep fed 8 meals per day or 1 meal plus 7 ruminal inflations-deflations than by those fed 1 meal per day. However, the gain in DM and energy of wool was not affected by frequency o( meals. (4) Sheep ingesting 8 meals or administered 1 meal plus 7 ruminal inflations-deflations per day gained body protein, fat and energy at a more rapid and efficient rate than sheep fed 1 meal per day. (5) Sheep fed 8 meals per day gained greater proportion of fat, protein and ash in the gained portion of the bodies than did 1 meal fed sheep. (6) An attempt was made to establish the possible explanations by which the frequency of ingesting meals exerts its effects.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.464-473
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• 2008

Winter migratory birds gather in paddy rice fields to feed shed rice grains. The Korean Ministry of Environment has practiced a policy program Contract on Paddy Field Management (CPFM) during winter fallow since 2002. This program starts with a contract between local governments and farmers, and the government pays a differential subsidy to farmers who finish spreading rice straw, cultivating barley, letting the whole rice plant without harvest, and submerging paddy fields for winter migratory birds. As more local governments have operated CPFM program, the total area on the contract and subsidy budget has increased yearly since 2002. This program could have its stable position as a successful policy by giving profits to farmers. With the program extended, the population of winter migratory birds has been greatly. For the evaluation of environmental performance of a policy, we analyzed this CPFM program by introducing some indicators in the form of Driving Force-State-Response Framework. The indicators were composed of 3 categorized indicators; the area of paddy land contracted under this program as 'driving force' indicator, population of birds, the number of bird species and the amount of feces as 'state' indicators, and the size of monetary support, the number of farmers or local governments participating, and public perception as 'response' indicators. The contract area of paddy field under CPFM could be a good biodiversity indicator reflecting potential performance of this policy measure in the light of its linkage to the population of winter migratory birds. And the share of CPFM land of the whole agricultural land might also be used as a useful indicator of policy evaluation for improvement of wildlife diversity. The 'state' indicators such as population of birds and the number of bird species could be matched to 'driving force' indicator, but the total CPFM area of each site could not reflect the effect of areas under different management practices. However, the amount of bird feces could reflect differences in environmental performance with management practices as 'state' indicators. The development of indicators indicating 'response' such as farmers' behavior, public perception, and policy makers' willingness is also needed to support a successful implementation and improvement of this policy measure with the development of 'performance' indicators integrating all these indicators.

• Journal of Aquaculture
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• v.16 no.1
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• pp.24-30
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• 2003

Studies of the seed production of Urechis unicinctus were conducted under the laboratory conditions to obtain some information for the U.unicinitus culture. The experiment included developmental studies of the egg development, larval culture, sediment preference and growth of young U.unicinctus. The experiment were conducted from March to August, 2000. The adults of U.unicinctus collected in Namhae-do, Korea. The developments of the fertilized eggs were observed under a light-microscope at intervals of one hour after containing with density of one individual per 1 $m\ell$. The larvae were fed with Phaeodactylum tricornutum cultured at the laboratory. The concentration of the phytoplankton for the feed was 30,000 cells per individual larva. With progress of development, the food concentration was gradually increased, up to 10,000 cells per individual for the young U.unicinctus. Trochophore larvae appeared on the 68 hours after hatching. On the 32 days after hatching, over 50% of fertilized eggs developed into young U.unicinctus. In order to investigate the effect of sediment on the growth and burrowing of U.unicinctus, the young worms were reared in tanks with different grain sizes. The highest value of sediment preference and survival rate of U.unicinctus was shown in the mixture sediment group with below 0.10 mm, 1.01∼12.00 mm, over 3.01 mm and shell. The lowest value in both sediment preference and survival rate of U.unicinctus was observed in 1.0l∼2.00 mm grain size.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.3
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• pp.386-394
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• 2018

Objective: This experiment evaluated the effect of dietary supplementation levels of rapeseed meal (RSM) in gestation diets on reproductive performance, blood profiles, milk composition of sows, and growth of their progeny. Methods: A total of 55 mixed-parity sows ($Yorkshire{\times}Landrace$; average parity = 3.82) with an initial body weight (BW) of 193.0 kg were used in this experiment. Sows were allotted to one of 5 treatments at breeding based on BW and backfat thickness in a completely randomized design. Treatments consisted of dietary RSM supplementation levels (0%, 3%, 6%, 9%, and 12%) in gestation diets. During lactation all sows were fed a common lactation diet with no RSM supplementation. Results: Body weight, backfat thickness, litter size, lactation feed intake, and milk composition of sows, and growth of their progeny were not different among dietary treatments. In blood profiles, a quadratic increase (Quadratic, p<0.05) in serum triiodothyronine (T3) concentration and a linear increase (Linear, p<0.01) in serum thyroxine (T4) concentration were observed at d 110 of gestation as dietary RSM supplementation levels increased. However, serum T3 and T4 concentrations in lactating sows and their piglets were not affected by RSM supplementation of gestation diets. Concentrations of serum total cholesterol and low density lipoprotein cholesterol in sows were not influenced by dietary treatments, whereas serum glucose level in sows decreased linearly at d 110 of gestation (Linear, p<0.05) by increasing dietary RSM supplementation in gestation diets. Conclusion: The RSM could be supplemented to gestation diets up to 12% with no detrimental effects on reproductive performance and growth of their progeny. However, increasing supplementation levels of RSM in gestation diets may increase serum T3 and T4 concentrations and decrease serum glucose concentration of sows in late gestation.

• Korean Journal of Environment and Ecology
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• v.31 no.5
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• pp.472-478
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• 2017

The feeding habits of Coreoperca herzi were investigated from specimens collected in the Geum River, from March to December 2016. The specimens were separated into groups of 38~70 mm, 71~109 mm, and over 110 mm in total length. The live foods of C. herzi included Ephemeroptera, Odonata, Plecoptera, Coleoptera, Diptera, Trichoptera, and fishes. The Korean aucha perches fed mostly on aquatic insects which took up 98.8% of food regarding the number, 55.8% regarding the biomass, and 97.1% in terms of iregarding the index of relative importance. They were carnivorous in diet and predators (stalker) in food intake characteristics and forms when applying Keenleyside's classification. The main food sources of C. herzi were Ephemeroptera, Diptera, and Trichoptera while Odonata, Plecoptera, Coleoptera, and fishes were rare. A food migration was observed since less Ephemeroptera was found and more Trichoptera and fishes were found in the biomass of the feed consumed by larger species. The amount of Coleoptera and Diptera did not change much with the size of the species. The overall composition of live food was not seasonal. The result of the study indicates that, when restoring the streams to be the habitat for the natural population increase of Coreoperca herzi, the environment should be inhabitable to Ephemeroptera, Diptera, and Trichoptera which are the main foods.

• Clean Technology
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• v.24 no.3
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• pp.239-248
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• 2018

In this study, pervaporation experiments of water, ethanol and IPA (Isopropyl alcohol) single components and water/ethanol, water/IPA mixtures were carried out using zeolite 4A membranes developed by Fine Tech Co. Ltd. Those membranes were fabricated by hydrothermal synthesis (growth in hydrothermal condition) after uniformly dispersing the zeolite seeds on the tubular alumina supports. They have a pore size of about $4{\AA}$ by ion exchange of $Na^+$ to the LTA structure with Si/Al ratio of 1.0, and shows strong hydrophilic property. Physical characteristics of prepared membranes were evaluated by using SEM (surface morphology), porosimetry (macro- or meso- pore analysis), BET (micropore analysis), and load tester (compressive strength). Pervaporation experiments with various temperature and concentration conditions confirmed that the zeolite 4A membrane can selectively separate water from ethanol and IPA. Water/ethanol separation factor was over 3,000 and water/IPA separation factor was over 1,500 (50 : 50 wt%, initial feed concentration). Pervaporation behaviors of single components and binary mixtures were predicted using ACM (activity coefficient model), GMS (generalized Maxwell Stefan) model and DGM (Dusty Gas Model). The adsorption and diffusion coefficients of the zeolite top layer were obtained by parameter estimation using GA (Genetic Algorithm, stochastic optimization method). All the calculations were carried out using MATLAB 2018a version.

• Clean Technology
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• v.13 no.1 s.36
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• pp.34-45
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• 2007

Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dichloromethane and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing dichloromethane as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of dichloromethane and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the dichloromethane composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature. The second half of this work is focused on the particle formation of the simvastatin drug by a supercritical anti-solvent recrystallization process in a cylindrical high-pressure vessel equipped with an impeller. Microparticles of the simvastatin drug were prepared as functions of pressure (8 MPa to 12 MPa), temperature (303.15 K, 313,15 K), feed flow rate of carbon dioxide, and stirring speed (up to 3000 rpm), in order to observe the effect of those process parameters on the size and shape of the drug microparticles recrystallized.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.963-968
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• 1997

Cereals and legumes were ground, blended and extruded with a twin-screw extruder to form a reconstituted grain. The basic formula was as follows: brown rice 30%, barley 30%, wheat 20%, millet 5%, sorghum 5%, soybean 7%, and red bean 3%. Extrusion conditions were properly set for feed moisture content of $24{\sim}30%$, barrel temperature of $50{\sim}60^{\circ}C$, and screw speed at 250 rpm. The extruded grain was air-dried and evaluated for quality characteristics, compared with milled rice. Size and shape of the reconstituted grain were similar to short-grain milled rice. Stacking volume of the reconstituted grain was a little higher than that of milled rice, and its water absorption was more rapid. From the texture measurements, hardness of cooked reconstituted grain was slightly lower and adhesiveness was appeared to be higher.