• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3C
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• pp.93-102
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• 2011

Most experimental studies on soil liquefaction are related to clean sands. However, soils in the field or reclaimed grounds commonly contain some amounts of silt and clay rather than clean sand only. Many researchers investigated the effect of fine contents on liquefaction resistance and mainly used non-plastic fines such as silts. In this study, 10% of plastic fines with various plasticity index (PI) such as 8, 18, 50, and 377 were mixed with wet Nakdong River sand and then loose, medium, and dense specimens were prepared by undercompaction method. A series of undrained cyclic triaxial tests were carried out by applying three different cyclic stress ratios. As a result, the liquefaction resistance tended to decrease as a PI of fines in the specimens with equal fine content increased. On the other hand, the difference between loose specimens with low and high plasticity fines was not clearly observed in terms of liquefaction resistance. However, in the case of dense specimens, liquefaction resistance decreased up to 40% as a plasticity of fines increased.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.429-441
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• 2011

In the southeast coastal zone of Yellow Sea, the tide characteristics showing ebb-dominant tide and tidal flow were confirmed by analysis of observed tide and tidal currents. Physical factors generating asymmetric tide were reviewed. Influence of bottom shear stress, tidal flat, and nonlinear terms in shallow water equations was investigated by two-dimensional tide modeling. The model results gave good agreements with observed tides, but the amplitude of simulated $M_4$ tide was less than that of observed tide. The tidal flats existing in the study area widely have great effect on the generation of nonlinear tide. The M4 tide is mainly generated near the tidal flats. The deletion of tidal flats prevents the production of the M4 tide. We can conclude that the wide tidal flats is a primary cause of tide asymmetry in the study area.

• Textile Coloration and Finishing
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• v.18 no.1
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• pp.33-43
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• 2006

The purpose of this study was to eximine the effect of different yam twisting methods on mechanical properties and 3D CAD images of plain knitted fabrics made of composite yarns. Six yams were used in this study: four different composite yams of the six consist of acetate and functional polyester (Poly-m) with the ratio of 70:30, and the rest two are the original acetate $100\%$ yam and the poly-m $100\%$ yarn. The four kinds of composite yarns were processed in combinations of twisting processes such as interlacing, false twisting, two for one twisting, combined twisting and single covering, and the two original yams were knitted without any twisting process. Sixteen mechanical properties of all the six knitted fabrics, knitted under the same knitting conditions, were measured by KES-FB system with the outer knit condition. The results were as follows; 1) When the sample applied with the false twisting process at the temperature as high as $220^{\circ}C$, ENT, B, HB, G and RC values of samples increased which leads to increasing dimensional stability. 2) To gain the high bending and shear properties in the single covering process, selecting the core yarn with such properties is the most important factor. 3) Interlacing process effected to increase RC value. 4) False twisting process after interlacing process gave bulkiness and un-interlaced part in yam was increased SMD value. The SMD value of the kilted fabric of the composite yarn, which was put through the combined twist process, was higher than those of which simple process such as the two for one twist or the single covering process applied. In order to achieve the silk-like surface feel of knitted fabric, the sin91e covering process is recommended. 5) Examining the simulation images of the knifed fabrics of composite yarn, which were generated by the 3D CAD system based on the mechanical properties of the fabric, led that appearance could be changed as different twisting methods were applied.

• Korean Journal of Poultry Science
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• v.31 no.3
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• pp.193-198
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• 2004

This study was conducted for improvement of meat quality in broiler chcikens. Birds were fed basal diet(control), ferritin, illite, betafin, or wood vinegar counting broiler feed according as broiler growth stage. Birds fed with basal diet, which was distributed under the best environmental condition, were more weight gain than other groups reared under same environmental condition. In the mean weight gain, the ferritin-group showed the highest and the illite-group showed the lowest among the feed additive groups; therefore, the effect of feed requirement change in odor reduction in illite and methyl saving of betafin was lower than those of other feed additives along to pass rear time. Meat quality was appraised by National Livestock Research Institute of RDA. Except the control-group, that had the best feed conversion ratio, the cooking loss of the illite-group was the biggest among groups although the illite-group chickens had a good water hold capacity. Therefore, illite is not good for making merchandise by reason that group chickens get reduction carcass weight after slaughter. On the other hand, the ferritin-group got the highest point of shear stress, cooking loss, and crude fat level. That group showed the best appraise in both breast and leg of sensory test in company and also feed conversion ratio was the highest among feed additive groups. As a result, the ferritin-group might use for making new merchandise among the feed additive groups.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.45-45
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• 2009

원가 측면에서 유리한 저항점용접(Resistance Spot Welding)이 차체 용접에 80%이상으로 가장 많이 적용되고 있다. 첨단고강도강(Advanced High Strength Steel)의 저항점용접성 및 용접부 특성에 미치는 공정 변수의 영향에 대한 연구결과는 많으나, 합금원소의 영향에 대해서는 전무하다. 특히, Si는 DP(Dual Phase)강에 첨가 시 균일한 마르텐사이트의 분포를 촉진하는 원소로 저항 점용접성 및 용접부 특성에 영향을 미칠 것으로 예상되며, 이에 대한 연구는 보고된바 없다. 본 연구에서는 냉연 DP강의 저항 점용접시 중요한 인자 중 하나인 너깃경과 전단인장강도에 미치는 Si함유량의 영향을 검토하였다. 사용된 강재 및 용접기는 1.2mm 두께의 Si함유량(0, 0.5, 1.0, 1.5wt%)이 다른 인장강도 780~1000MPa급 냉연 DP강과 단상 AC용접기를 사용하였다. 용접조건은 ISO 18278-2규격에 따라 가압력 4kA, 초기가압시간 40cycle, 유지시간 17cycle로 고정하고, 용접전류만 변화하여 용접을 실시하였다. 너깃경은 용접부 단면을 컷팅 후 폴리싱 하여, 광학현미경과 Image Pro plus를 이용하여 측정했으며, 인장시편규격은 JIS Z 3137를 이용하였다. Si함유량이 증가에 따라 스패터 발생 전류는 감소했고, 너깃경은 직선적으로 증가했다. Si함유량 증가에 따른 너깃경 증가 이유는 저항(R) 측정결과, Si함유량 증가에 따라 모재의 저항이 높아져, 따라서 입열량($Q=I^2Rt$)이 많아지기 때문으로 판단되었다. 인정전단강도는 Si함유량 증가에 따라 직선적으로 증가했다. 이러한 이유는 Si함유량 증가에 따라 너깃경이 증가되기 때문으로 판단되었고, 너깃경과 인장전단강도 사이에 직선적 관계(PL(kN)=$3.2N_{dia.}$-0.81, $R^2$=0.93)를 가지고 있었다. 파단양상은 Si함유량에 상관없이 5.4kA이하에서는 계면파단이 일어났고, 6.0kA이상에서는 풀 아웃 파단이 일어났다. 계면파단주원인은 용접부 가장자리에 지름이 약 $5{\mu}m$이하의 예리한 노치가 존재하여 노치응력집중과 HAZ계면 근처에 미접합부가 존재하기 때문으로 판단되었다. 6.0kA이상에서는 예리한 노치가 없었고, HAZ부가 완전히 접합되어 있기 때문에 풀 아웃 파단이 일어난 것으로 판단되었다. 따라서, Si함유량 증가에 따라 적정용접전류 구간은 감소했고, 너깃경은 직선적으로 증가했다. 또한, Si함유량 증가에 따라 인장전간강도는 증가 했으며, 너깃경과 인장전단강도 사이에 직선적 관계를 가지고 있었다. 파단 양상은 Si함유량에 상관없이 5.2kA이하에서는 계면파단이, 6.0kA이상에서는 풀 아웃 파단이 일어났다.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.705-711
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• 1999

Post-mortem pork loins were used to investigate the effects of gamma irradiation on the surface and inside color, heme pigments, muscle protein solubility, purge loss, electrophoretical patterns of muscle proteins, and tenderness. The muscle was cut into pieces of 5 cm in length and divided into both groups, vacuum-packaged and air-packaged. The packaged samples were irradiated at designed doses, 0, 1, 3, 5 and 10 kGy, by a cobalt-60 irradiator, and stored at $4^{\circ}C$ for 7 days. There were no significant differences in the purge loss and electrophoretic patterns. Hunter's L and a values of the surface and inside of loins increased by gamma irradiation, showing a bright red color and the red color was maintained during the storage of both samples. However, the concentrations of heme pigments were not significantly changed. Muscle protein solubility slightly increased by increasing the applied dose. The decrease in shear force was observed in irradiated samples. As result, it was expected that meat quality, especially color and processing properties, could be improved by gamma irradiation at below 5 kGy.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.265-270
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• 2005

This study was carried out to investigate the effects of washing times on quality characteristics of chicken breast surimi. The surimi was prepare after 2 (C), 4 (T1) and 6 (T2) times washed with a ratio 6 : 1 distilled water-chicken breast meat. The moisture and crude protein content of T1 and T2 were higher than that of C. The myofibrillay protein and yield of C was higher (p<0.05) than those of T1 and T2. The pH of C was higher (p<0.05) compare to other treatments. The WHC was no significant differences between the all treatments. The shear force of all treatments were tended to higher as washing times increased. The breaking force and deformation value of T2 were lower than other treatments. The $L^{*}$ values in C and $b^{\ast}$ values in T1 were significantly (p<0.05) lower among the treatments group. The hardness and gumminess of T1 was higher (p<0.05) compared to T2. The springiness of treatments increased as washing times increased. The sensory score of surimi made from chicken breast meat was not affected by the washing times.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.604-611
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• 2012

The purpose of this study was to explore the effect of fermented persimmon diet on the meat quality of fattening pigs. Pigs (75 kg) were grouped and housed as 15 animals per pen and 3 replications per treatment. The basal diet (C) was substituted with 3% (T1), 5% (T2) and 10% (T3) of fermented diet. The 180 pigs were fed experimental diet for 42 d and 10 longissimus dorsi (LD) per treatment were collected when each swine reached 105.6 kg of body weight. The crude fat concentration of LD was lower (p<0.05) in treatments, but the pH value of T3 and the shear force values of T2 and T3 were higher (p<0.05) than those of C. The CIE $L^*$ value (lightness) was significantly (p<0.05) higher in T2 and T3 than C, but the CIE $b^*$ (yellowness) of T2 and T3 was significantly (p<0.05) lower than C. The composition of myristic acid and oleic acid was significantly (p<0.05) higher in treatments than in C, while the composition of palmitic acid and stearic acid of treatments were significantly (p<0.05) lower than C in LD. Sensory evaluation of cooked meat as scores of aroma, taste, juiciness and overall acceptability showed higher (p<0.05) in treatments than in C. In conclusion, the dietary of fermented persimmon diet decreased the crude fat concentration, improved the fatty acids composition (increased composition of unsaturated fatty acid and decreased composition of saturated fatty acid) and improved the sensory evaluation of pork meat from fattening pigs.

• 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.

• Journal of Animal Science and Technology
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• v.48 no.2
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• pp.287-292
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• 2006

The purpose of this study was to assess the influence of ageing time on the meat quality and sensory characteristics of longissimus muscle in Jeju horses. Twenty four horses were slaughtered after 16hr fasting. Longissimus muscle was separated from the left half of the carcass after 24hr chilling. The muscle was sliced into 3cm-thick steaks for analysis. Steaks were vacuum packaged and aged at around 4℃ for 1, 3, 7, 12, 18 and 25 days respectively. Longissimus muscle pH was not influenced by ageing (P>0.05). But shear force values of the muscle decreased during ageing time (P<0.05). Water holding capacity, color characteristics, cooking loss and purge loss considerably increased as the ageing time increased (P<0.05). Also ageing had a very important effect on flavor, juiciness, tenderness and palatability characteristics (P<0.05) evaluated by the panel. Flavor and palatability were the most acceptable when the ageing time was 7 days, whereas, juiciness was 12 days. These results suggest that ageing improves the quality of horsemeat by increasing the meat tenderness, water holding capacity and sensory characteristics. Therefore Jeju horse meat need 7-12 days ageing period to obtain an optimum acceptance.