• Korean Journal of Poultry Science
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• v.40 no.4
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• pp.351-359
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• 2013

This study was undertaken to assess dietary crude protein (CP) and amino acid (AA) concentrations for growth performance and carcass characteristics in Korean native ducks. In a $2{\times}3$ factorial arrangement, 1-d-old Korean native male ducks were allotted to 6 dietary treatments in a completely randomized design. Experimental diets contained 23 or 21% CP with 1.31/1.09, 1.21/1.00, 1.11/0.91 and 1.11/0.91, 1.02/0.83, 0.92/0.75 AA (Lysine/Total sulfur amino acid, Lysine/TSAA), respectively, from 0 to 3 wk of age. From 4 to 8 wk of age, experimental diets had 19 or 17% of diet; each contained 1.00/0.79, 0.94/0.75, 0.88/0.71 and 0.88/0.71, 0.82/0.67, 0.76/0.63 AA (Lysine/TSAA), respectively. Each dietary treatment has 6 replicates and feed and water were provided ad libitum. Body weight (BW), feed intake and uniformity were measured at 3 wk and 8 wk and carcass characteristics were evaluated at 8 wk of age. As CP increased from 21 to 23%, the BW and BW gain significantly increased (P<0.05) during 0 to 3 wk of age. From 4 to 8 wk of age, BW, feed intake, BW gain, feed conversion rations (FCR) and uniformity were not different (P>0.05) between treatments. Carcass yield and relative weights of liver, spleen, right breast and leg per 100 of BW were not different (P>0.05) between treatments. The meat color, shear force value, cooking loss and pH were not affected by dietary treatments (P<0.05). Korean native ducks require relatively low levels of dietary CP and AA for late growth and carcass yield due to low daily weight gain. This suggests the possible differences in CP and AA needs between Korean native ducks and commercial breeds from foreign breeding companies, especially late growth stage.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.284-289
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• 2007

This study was conducted to investigate the effects of copper and zinc supplementation on growth performance, nutrient digestibility, and meat and carcass characteristics in finishing pigs. A total of 72 $(Landrace{\times}Yorkshire{\times}Duroc)$ pigs (58.47 kg initial BW) were assigned to 6 treatments in a $2{\times}3$ factorial design $(Zn\;levels{\times}Cu\;levels)$. The sources of zinc and copper were Zn-methionine chelate and Cu-methionine chelate, respectively. Zinc levels used were 80 and 120 ppm and copper levels used were 10, 30 and 60 ppm. Throughout the entire experimental period, the average daily gain (ADG) and average daily feed intake (ADFI) were not significantly affected by Cu or Zn levels, or their relative levels. The G:F ratio was significantly affected by the relative levels of Cu and Zn (p<0.05), specifically at 30 ppm Cu and 120 ppm Zn. Dry matter digestibility was significantly affected by the levels of Cu (p<0.02), Zn (p<0.01) and the relative levels of each (p<0.04), in particular at 30 ppm Cu and 120 ppm Zn. Nitrogen digestibility was significantly affected by Zn levels (p<0.01) and the combination of 30 ppm Cu and 120 ppm Zn (p<0.03). The $L^*-value$, shear force, cooking loss and pH were not significantly affected by Cu levels, Zn levels or their combination. The $a^*- (p<0.04)\;and\;b^*- values (p<0.01)$ were significantly affected by Zn levels at 80 ppm. The Water hoding capacity was significantly affected by Cu and Zn in combination (p<0.01) at 10 ppm Cu and 120ppm Zn. The carcass weight, backfat thickness and carcass grade were not significantly affected by Cu levels, Zn levels or their relative levels. The carcass percentage was significantly affected by the combination (p<0.04) of 30ppm Cu and 120ppm Zn. In conclusion, dietary supplementation of Cu and Zn at 30 and 120 ppm, respectively, is effective for feed efficiency, nutrient digestibility and carcass percentage, while at the levels of Cu at 10 ppm and Zn at 120 ppm have effects on WHC.

• Journal of the Korean Geotechnical Society
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• v.36 no.2
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• pp.5-15
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• 2020

The liquefaction phenomenon that occurred during the Pohang earthquake (M_L=5.4) brought new awareness to the people about the risk of liquefaction caused by the earthquake. Liquefaction hazard maps with 2 km grid made in 2014 used more than 100,000 borehole data for the whole country, and regions without soil investigation data were produced using interpolation. In the mapping of macro liquefaction hazard for the whole country, the site amplification effect and the ground water level 0 m were considered. Recently, the Ministry of Public Administration and Security (2018) published a new site classification method and amplification coefficient of the common standard for seismic design. Therefore, it is necessary to rewrite the liquefaction hazard map reflecting the revised amplification coefficient. In this study, the results of site classification according to the average shear wave velocity in soils before and after revision were compared in the whole country. Also, liquefaction assessment results were compared in Gangseo-gu, Busan. At this time, two ground accelerations corresponding to the 500 and 1,000 years of return period and two ground water table, 5 m for the average condition and 0 m the extreme condition were applied. In the drawing of liquefaction hazard map, a 500 m grid was applied to secure a resolution higher than the previous 2 km grid. As a result, the ground conditions that were classified as S_C and S_D grounds based on the existing site classification standard were reclassified as S₂, S₃, and S₄ through the revised site classification standard. Also, the result of the Liquefaction assessments with a return period of 500 years and 1,000 years resulted in a relatively overestimation of the LPI applied with the ground amplification factor before revision. And the results of this study have a great influence on the liquefaction assessment, which is the basis of the creation of the regional liquefaction hazard map using the amplification factor.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.527-534
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• 2008

Effects of dietary concentrate levels based on whole-crop barley silage (BS) on development and meat quality in growing Korean black goats were examined. A total of 36 male goats with similar age and BW were equally allocated to dietary four treatments in a randomized complete block design. Dietary treatments included controls(rice straw ad libitum plus 2.0% concentrate BW－1), and BS ad libitum plus three increasing levels of concentrate BW－1(2.0, 1.5 and 1.0%, respectively), expressed as BS 2.0, BS 1.5 and BS 1.0, respectively. The trial was lasted for 5 months from 14th of May to 12th of October, 2007. At the end of trial, all animals were slaughtered to analyze carcass characteristics and meat quality. Average daily gain was significantly(p<0.05) higher for BS 1.5 and BS 2.0 treatments than for controls. Daily feed intakes for controls(689.3 g) were significantly(p<0.05) higher than those of BS 1.0(585.5 g), but they were significantly(p<0.05) lower than BS 2.0(734.3 g). Carcass and meat percentages were significantly (p<0.05) higher for BS 2.0 and BS 1.5 than for control and BS 1.0 treatments. Shear force and water-holding capacity was greater(p<0.05) for BS 2.0 and BS 1.5 than other treatments. On the basis of feeding whole-crop barley silage to Korean black goats, as dietary concentrate inclusion levels increased, sensory results showed to have a better tendency. In conclusion, it was estimated that the optimal level of dietary concentrates might be 1.5% BW－1, when diets based whole-crop barley silage were fed to growing Korean black goats for their improvements of growth and meat quality.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.167-175
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• 2012

This study was undertaken to assess dietary CP and ME concentrations for optimum growth performance and carcass characteristics of Korean Native male ducks. In a $3{\times}3$ factorial arrangement, 1-d-old Korean Native male ducks were completely randomized design to experimental diets with 3,000, 2,900, and 2,800 kcal of ME/kg of diet; each contained 23, 22, and 21% CP, respectively, from 0 to 3 wk of age. From 4 to 8 wk of age, experimental diets had 3,100, 3,000, and 2,900 kcal of ME/kg of diet, and each contained 19, 18, and 17% CP, respectively. Each dietary treatment was replicated 4 times, and feed and water were provided ad libitum. Body weight, feed intake and uniformity were measured at 3 wk and 8 wk, and carcass characteristics were evaluated at 8 wk. As CP increased from 21 to 23 %, the body weight, BW gain and feed conversion ratios (FCR) linearly improved (P<0.01) during 0 to 3 wk of age. From 4 to 8 wk of age, the body weight, feed intake, BW gain, FCR and uniformity were not different (P>0.05). Carcass ratios of birds fed 3,000 kcal of ME/kg diets from 3 to 8 wk of age were quadratically increased significantly (P<0.01). As ME and CP increased, respectively, relative weight of liver weight per 100 g of BW was linearly decreased (P<0.01). Relative weights of left breast, thigh and drumstick weight per 100 of BW were not different (P>0.05). Also, breast meat color, pH, cooking loss and shear force were not different (P>0.05). Thus, diets with 2,800 kcal of ME/kg and 23% CP or with 2,900 kcal of ME/kg and 17% CP at 0 to 3 wk and 4 to 8 wk, respectively, were used more efficiently. However, diets with 3,000 kcal of ME/kg at 4 to 8 wk in carcass rate was quadratically increased.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.275-283
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• 2012

Steel Plate for Rebar Connection was recently developed to splice rebars in delayed slab-wall joints in high-rise building, slurry wall-slab joints, temporary openings, etc. It consists of several couplers and a thin steel plate with shear key. Cyclic loading tests on slab-wall joints were conducted to verify structural behavior of the joints having Steel Plate for Rebar Connection. For comparison, joints with Rebend Connection and without splices were also tested. The joints with Steel Plate for Rebar Connection showed typical flexural behavior in the sequence of tension re-bar yielding, sufficient flexural deformation, crushing of compression concrete, and compression rebar buckling. However, the joints with Rebend Connection had more bond cracks in slabs faces and spalling in side cover-concrete, even though elastic behavior of the joints was similar to that of the joints with Steel Plate for Re-bar Connection. Consequently, the joints with Rebend Connection had less strengths and deformation capacities than the joints with Steel Plate for Re-bar Connection. In addition, stiffness of the joints with Rebend Connection degraded more rapidly than the other joints as cyclic loads were applied. This may be caused by low elastic modulus of re-straightened rebars and restraightening of kinked bar. For two types of diameters (13mm and 16mm) and two types of grades (SD300 and SD400) of rebars, the joints with Steel Plate for Rebar Connection had higher strength than nominal strength calculated from actual material properties. On the contrary, strengths of the joints with Rebend Connection decreased as bar diameter increased and as grade becames higher. Therefore, Rebend Connection should be used with caution in design and construction.

• Korean Journal of Agricultural Science
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• v.14 no.1
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• pp.98-133
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• 1987

The mechanical and rheological properties of agricultural materials are important for engineering design and analysis of their mechanical harvesting, handling, transporting and processing systems. Agricultural materials, which composed of structural members and fluids do not react in a purely elastic manner, and their response when subjected to stress and strain is a combination of elastic and viscous behavior so called viscoelastic behavior. Many researchers have conducted studies on the mechanical and rheological properties of the various agricultural products, but a few researcher has studied those properties of rice plant, and also those data are available only for foreign varieties of rice plant. This study are conducted to experimentally determine the mechanical and the rheological properties such as axial compressive strength, tensile strength, bending and shear strength, stress relaxation and creep behavior of rice stems, and grain detachment strength. The rheological models for the rice stem were developed from the test data. The shearing characteristics were examined at some different levels of portion, cross-sectional area, moisture content of rice stem and shearing angle. The results obtained from this study were summarized as follows 1. The mechanical properties of the stems of the J aponica types were greater than those of the Indica ${\times}$ Japonica hybrid in compression, tension, bendingand shearing. 2. The mean value of the compressive force was 80.5 N in the Japonica types and 55.5 N in the Indica ${\times}$ Japonica hybrid which was about 70 percent to that of the Japonica types, and then the value increased progressively at the lower portion of the stems generally. 3. The average tensile force was about 226.6 N in the Japonica types and 123.6 N in the Indica ${\times}$ Japonica hybrid which was about 55 percent to that of the Japonica types. 4. The bending moment was $0.19N{\cdot}m$ in the Japonica types and $0.13N{\cdot}m$ in the Indica ${\times}$ Japonica hybrid which was 68 percent to that of the Japonica types and the bending strength was 7.7 MPa in the Japonica types and 6.5 MPa in the Indica ${\times}$ Japonica hybrid respectively. 5. The shearing force was 141.1 N in Jinju, the Japonica type and 101.4 N in Taebaeg, the Indica ${\times}$ Japonica hybrid which was 72 percent to that of Jinju, and the shearing strength of Taebaeg was 63 percent to that of Jinju. 6. The shearing force and the shearing energy along the stem portion in Jinju increased progressively together at the lower portions, meanwhile in Taebaeg the shearing force showed the maximum value at the intermediate portion and the shearing energy was the greatest at the portion of 21 cm from the ground level, and also the shearing strength and the shearing energy per unit cross-sectional area of the stem were the greater values at the intermediate portion than at any other portions. 7. The shearing force and the shearing energy increased with increase of the cross-sectional area of the rice stem and with decrease of the shearing angie from $90^{\circ}$ to $50^{\circ}$. 8. The shearing forces showed the minimum values of 110 N at Jinju and of 60 N at Taebaeg, the shearing energy at the moisture content decreased about 15 percent point from initial moisture content showed value of 50 mJ in Jinju and of 30 mJ in Taebaeg, respectively. 9. The stress relaxation behavior could be described by the generalized Maxwell model and also the compression creep behavior by Burger's model, respectively in the rice stem. 10. With increase of loading rate, the stress relaxation intensity increased, meanwhile the relaxation time and residual stress decreased. 11. In the compression creep test, the logarithmic creep occured at the stress less than 2.0 MPa and the steady-state creep at the stress larger than 2.0 MPa. 12. The stress level had not a significant effect on the relaxation time, while the relaxation intensity and residual stress increased with increase of the stress level. 13. In the compression creep test of the rice stem, the instantaneous elastic modulus of Burger's model showed the range of 60 to 80 MPa and the viscosities of the free dashpot were very large numerical value which was well explained that the rice stem was viscoelastic material. 14. The tensile detachment forces were about 1.7 to 2.3 N in the Japonica types while about 1.0 to 1.3 N in Indica ${\times}$ Japonica hybrid corresponding to 58 percent of Japonica types, and the bending detachment forces were about 0.6 to 1.1 N corresponding to 30 to 50 percent of the tensile detachment forces, and the bending detachment of the Indica ${\times}$ Japonica hybrid was 0.1 to 0.3 N which was 7 to 21 percent of Japonica types. 15. The detachment force of the lower portion was little bigger than that of the upper portion in a penicle and was not significantly affected by the harvesting period from September 28 to October 20. 16. The tensile and bending detachment forces decreased with decrease of the moisture content from 23 to 13 percent (w.b.) by the natural drying, and the decreasing rate of detachment forces along the moisture content was the greater in the bending detachment force than the tensile detachment force.

• Korean Journal of Organic Agriculture
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• v.16 no.3
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• pp.309-320
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• 2008

This study was conducted to determine the effects of different types of hilly pasture grazing on growth and meat quality in organic Korean black goats, and to obtain basic data for the production of organic goats. A total of 40 goats with similar age and BW were equally allocated to four dietary treatments in a randomized complete block design. Dietary treatments included grazing types of four different hilly pastures; T1: forages types, T2: organic forages types, T3: native plants types, and T4: browse types, respectively. The trial lasted for 174 days from 15th of May to 5th of November, 2007 in Livestock Genetic Resources Experiment Station, National Institute of Animal Sciences. At the end of trial, all animals were slaughtered to analyze carcass characteristics and meat quality. Average daily gain was significantly (p<0.05) higher for T1 treatments than for others. Dressing percentage was significantly (p<0.05) higher for T1 and T2 than for T3 and T4 treatments. Meat percentage of T1 treatments was significantly (p<0.05) higher than those of other treatments. For meat properties, crude fat content was highest in T3 treatments. Linoleate (18:2n6) and linolenate (18:3n3) contents tended to be higher in T1 than those of other treatments, while arachidonate (20:4n6) content tended to be higher in T3 and T4 than that of other treatments. Shear force was lower (p<0.05) for T3 than other treatments. For sensory results, juiciness and tenderness tended to be greater (p<0.05) in T2 and T3, and flavour tended to be greater (p<0.05) in T3 and T4. The results indicated that grazing in hilly pastures for organic Korean black goats was somewhat less in their performances and carcass characteristics, but not behind in the meat quality and physical characteristics as compared with the conventional regimen. Therefore, it would be expected that goats grazing in hilly pastures made it possible to produce organic animal products with a high safety and also might lead to increase of breeders income and consumers satisfaction.

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.227-238
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• 2021

This study investigates the effect of perch type and height on the growth performance, footpad dermatitis (FPD), blood parameters, behavioral characteristics, and meat quality of broilers. A total of 912 one-day-old male Ross 308 broilers (48.23±0.264 g) were subjected to a three x two factorial design of three types of perch (wood, steel, plastic) and two levels of perch height (10→30 cm change, 10 cm fixed) over a five-week experiment. Growth performance, perch availability, litter quality, FPD incidence, serum biochemical parameters, and meat quality of the broilers were evaluated. There were no significant differences in the body weight, feed conversion ratio, and biochemical parameters (except for aspartate aminotransferase), pH, color, and water holding capacity. The incidence of FPD was significantly higher in the plastic perch group than in the wood and steel perch groups (P<0.05) at five weeks of age. Perch use was high in the order of wood, steel, and plastic groups in the daytime and nighttime at one, three, and five weeks of age (P<0.05). Perch use was higher in the 10 cm fixed group than the 10→30 cm group (P<0.05). The shear force of the breast significantly increased in the order of wood, steel, and plastic groups (P<0.05). In conclusion, the group with a fixed perch height of 10 cm had high perch usage. Additionally, the use of wooden perches was higher than that of other materials, and it lowered the incidence of FPD in broilers.