• Journal of Korean Society of Water and Wastewater
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• v.34 no.3
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• pp.211-220
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• 2020

When domestic sewage and rainwater runoff are discharged into a single sewer pipe, it is called a "combined sewer system." The sewage design standards in Korea specify the flow velocity based only on the volume of rainfall; therefore, sedimentation occurs on non-rainy days owing to the reduced flow rate and velocity. This sedimentation reduces the discharge capacity, causes unpleasant odors, and exacerbates the problem of combined sewer overflow concentration. To address this problem, the amount of sewage on non-rainy days, not just the volume of rainfall, should also be considered. There are various theories on sedimentation in sewer movement. This study introduces a self-cleansing velocity based on tractive force theory. By applying a self-cleansing velocity equivalent to the critical shear stress of a sand particle, sedimentation can be reduced on non-rainy days. The amount of sewage changes according to the water use pattern of citizens. The design hourly maximum wastewater flow was considered as a representative value, and the velocity of this flow should be more than the self-cleansing velocity. This design method requires a steeper gradient than existing design criteria. Therefore, the existing sewer pipelines need to be improved and repaired accordingly. In this study, five types of improvement and repair methods that can maximize the use of existing pipelines and minimize the depth of excavation are proposed. The key technologies utilized are trenchless sewer rehabilitation and complex cross-section pipes. Trenchless sewer rehabilitation is a popular sewage repair method. However, it is complex because the cross-section pipes do not have a universal design and require continuous research and development. In an old metropolis with a combined sewer system, it is difficult to carry out excavation work; hence, the methods presented in this study may be useful in the future.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.322-327
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• 2005

This study was intended to provide basic information which might be useful in increasing added values to the pork from Korean native black pigs (KNP), through comparative evaluation on carcass characteristics and meat qualities between KNP and four exotic breed groups including Duroc (DD), Landrace (LL), Yorkshire (YY), and LYD-cross (1/4LL 1/4YY, 1/2DD), and the results were summarized as follows. Live weight carcass weight, dressed meat weight, skin weight, fat weight and bone weight of KNP were significantly (p<0.05) lower than those of DD, LL, YY and LYD-cross. Carcass yield and dressed meat yield were also significantly (p<0.05) lower in KNP than other 4 groups, however, total fat, skin, bone, kidney and kidney fat in percentage were significantly (p<0.05) higher for KNP than others. Dressed meat yield was highest for YY, followed by LYD-cross and KNP. Weight of belly was 6.12, 9.43, and 9.52 kg for KNP, YY and LYD-cross, respectively. Percent belly of KNP was $11.11\%$ while other groups ranged from 11.5 to $12.2\%$ Shear force value was not different among the treatments. KNP had significantly (p<0.05) lower water holding capacity (WHC), and cooking loss, but significantly (p<0.05) higher in juiciness comparatively. KNP had significantly (p<0.05) higher $a^{*}$ value while DD had significantly (p<0.05) lower than other breeds.

• Food Science of Animal Resources
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• v.26 no.1
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• pp.70-77
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• 2006

This study was carried out to evaluate the quality characteristics on the two different muscles (Loin; T1, Ham; T2) from the Cervus elaphus andadensis (Elk deer). The water content and shear force of T1 were lower than that of T2. The protein content and water holding capacity were lower in T2 compared to the T1. In meat color, $L^*,\;a^*\;and\;b^*$ values were not different between T1 and T2. In the texture properties, there were significantly (p<0.05) differences in hardness, adhesiveness, gumminess and brittleness, but cohesiveness and springiness were not different significantly (p<0.05). In fatty acid analysis, myristic acid and linoleic acid of T2 were high (p<0.05) as 5.06 and 10.37% respectively, while palmitoleic acid of T1 were significantly (p<0.05) higher than that of T2. SFA and UFA were not different between the T1 and T2, although EFA of T1 was significantly (p<0.05) higher than that of T2. In sensory evaluation, acceptability of T2 in fresh meat showed the slightly high, but that of T2 in cooked meat was slightly low score. All samples were not significantly different in overall acceptability.

• Food Science of Animal Resources
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• v.26 no.1
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• pp.28-36
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• 2006

This study was carried out to investigate the changes in physicochemical, microbiological and sensory properties on vacuum packaged Yakibuda products for Export during storage at $4{\pm}1^{\circ}C$ for 40 days. Yakibuda, Japanese favorite meat product, were produced with three different pork cuts or tenderloin (T1), loin (T2) and ham (T3). The pH of all produce was tend to increased with increase in storage period. After 40 days of storage, pH of T2 was significantly (p<0.05) higher compared to other treatments. TBARS and VBN values of all treatments were increased with increased storage period. The water holding capacity ranged $81.41{\sim}92.20%$ in T1, $81.13{\sim}94.51%$ in T2 and $82.93{\sim}87.50%$ in T3. The shear force of T3 was higher than that of other treatments during whole storage time. The number of microorganism (Total plate counts, Escherichia coli, Lactobacilli spp.) were below 3.0 $log_{10}CFU/cm^2$ during the whole storage period. In sensory evaluation, the score of overall acceptability were above 5.5 point in all products. The storage properties of vacuum packaged Yakibuda could be maintained for 40 days at $4{\pm}1^{\circ}C$ storage temperature.

• Food Science of Animal Resources
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• v.32 no.6
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• pp.749-755
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• 2012

This study was performed to investigate the physico-chemical properties of Holstein steer beef loin (M. longissimus dorsi) and top round (M. semimembranosus) from 18, 21 and 24-mon old. The loin and top round muscles from the 24-mon group had higher intramuscular fat content (%) than the other groups (p<0.05); however, the protein content was not significantly different among the 3 groups (p>0.05). With regard to meat color (CIE), the lightness ($L^*$), redness ($a^*$) and yellowness ($b^*$) values of the loin were significantly higher for the 21- and 24-mon groups, and those of the top round were significantly higher for the 21-mon group than the same cuts in the other groups. The Warner-Bratzler shear force was the lowest at 24 mon for both the loin and top round muscles (3.69 kg); however, the water holding capacity was significantly higher for loin muscles from the 21-mon group (54.53%, p<0.05). The loin muscles from the 24-mon group contained significantly higher levels of monounsaturated fatty acid and significantly lower levels of saturated fatty acid than those in the other groups (p<0.05). The tenderness, juiciness, flavor-likeness and the overall-likeness scores were significantly higher for beef from the 21- and 24-mon groups than that from the 18-mon group. The results of this study indicate that both the slaughtering age and muscle type significantly affect meat quality. Therefore, fattening the beef for more than 4 mon during the late fattening stage would be advantageous for the meat quality of Holstein steers.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.252-259
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• 2009

This study investigated the effects of ion water and premixed mineral supplementation on the growth performance, carcass, and meat quality parameters in finishing pigs ($LY{\times}D$). Each 20 pigs were randomly allotted to three treatments; CON (basal diet), T1(CON diet added with active water), T2 (T1 diet added with 1.0% premixed mineral). Used ion water and premixed mineral were consisted mainly of Zn and Si, respectively. Daily weight gain feed efficacy were the highest in T2, while fat content was the highest in control (p<0.05) than the others. However, the slaughter qualities including dressing percent, backfat thickness, marbling score, meat color, meat texture, drip loss, meat separation and meat qualities including pH, cooking loss, water holding capacity (WHC), shear force, meat color, backfat color, meat texture were not significantly different (p>0.05) among the treatment groups. Panel test scores of tenderness were the highest in T2 compared to the others.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.544-553
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• 2018

This study was conducted to determine the effects of breed and sex on meat quality and sensory properties of the loin in three-way crossbred pigs: $Landrace{\times}Yorkshire{\times}Duroc$ (LYD) and $Landrace{\times}Yorkshire{\times}Woori$ (LYW) black pig synthesized by Korean native breed. Carcass traits did not differ by breed. Carcass weight and backfat thickness were higher in castrates than in gilts (p<0.01). LYW showed significant high values in fat content, cooking loss, and water-holding capacity (WHC) than LYD (p<0.05). Redness and yellowness of the meat were higher in LYW than in LYD (p<0.01). Further, LYW had lower pH and shear force than LYD (p<0.001). Significant high scores in color and flavor were obtained in LYW or gilts compared to LYD or castrates by sensory panel, respectively (p<0.05). However, other sensory traits did not differ by breed or sex. Capric acid (C10:0) was higher in LYD than LYW (p<0.001). However, stearic acid (C18:0) and saturated fatty acid (SFA) contents were higher in LYW than LYD (p<0.05). Eicosenoic acid (C20:2) and the n6/n3 ratio were higher in gilts than in castrates, whereas SFA content was higher in castrates than in gilts. These results suggest that certain physicochemical qualities of meat and sensory properties are improved in LYW compared to LYD. This study could provide basic data on meat quality of crossbred pigs with Woori black pig as a terminal sire.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.4
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• pp.283-293
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• 2015

The buffer is a key component of the engineered barrier system in a high-level radioactive waste (HLW) repository. The present study reviewed the requirements and functional criteria of the buffer reported in literature, and also based on the results, proposed an approach to establish a buffer concept which is applicable to an HLW repository in Korea. The hydraulic conductivity, radionuclide-retarding capacity (equilibrium distribution coefficient and diffusion coefficient), swelling pressure, thermal conductivity, mechanical properties, organic carbon content, and illitization rate were considered as major technical parameters for the functional criteria of the buffer. Domestic bentonite (Ca-bentonite) and, as an alternative, MX-80 (Na-bentonite) were proposed for the buffer of an HLW repository in Korea. The technical specifications for those proposed bentonites were set to parameter values that conservatively satisfy Korea's functional criteria for the Ca-bentonite and Swedish criteria for the Na-bentonite. The thickness of the buffer was determined by evaluating the means of shear behavior, radionuclide release, and heat conduction, which resulted in the proper buffer thickness of 0.25 to 0.5 m. However, the final thickness of the buffer should be determined by considering coupled thermal-hydraulic-mechanical evaluation and economics and engineering aspects as well.

• Tunnel and Underground Space
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• v.30 no.4
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• pp.404-416
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• 2020

An analytical procedure for calculating the failure load of a V-shaped rock notch under two-dimensional stress conditions was developed based on the slip-line plastic analysis method. The key idea utilized in the development is the fact that the α-line, one of the slip-lines, extends from the rock notch surface to the horizontal surface outside the notch when the rock around the notch is in the plastic state, and that there exists an invariant which is constant along the α-line. Since the stress boundary condition of the horizontal surface outside the rock notch is known, it is possible to calculate the normal and shear stresses acting on the rock notch surface by solving the invariant equation. The notch failure load exerted by the wedge was calculated using the calculated stress components for the notch surface. Rock notch failure analysis was performed by applying the developed analytical procedure. The analysis results show that the failure load of the rock notch increases with exponential nonlinearity as the angle of the notch and the friction of the notch surface increase. The analytical procedure developed in this study is expected to have applications to the study of fracture initiation in rocks through wedge-shaped notch formation, calculation of bearing capacity of the rock foundation, and stability analysis of rock slopes and circular tunnels.

• Journal of Korean Society of Steel Construction
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• v.22 no.3
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• pp.271-280
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• 2010

This study was programmed to fabricate a beam-to-column connection that is limited to a steel-welded moment connection with full-scale members, using SN steel. A cyclic seismic test was conducted of the nine specimens that were fabricated by choosing the test variable for the weld access hole geometry, connection design method, and RBS. From the test results, failure modes, the moment-drift behavior, and the strain distribution were provided. From the specimen material properties, the beam's nominal plastic flexural capacity and classified qualified connection as a special moment flame were calculated. By analyzing the skeleton part and the baushinger part, a range of strength-raising effects, and deformation ratios were provided, with which the seismic performance of the specimens were evaluated. The test results showed that the specimens eliminated their weld access holes that demonstrated higher seismic performance than the specimens' existing weld access holes, and that the WUF-W connection that was reinforced by the supplemental fillet weld around the shear tap that was fastened by five bolts demonstrated superior seismic performance.