• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.45-53
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• 2015

This study has obtained Soil Water Retention Curve (SWRC) of the unsaturated soil from the volumetric pressure plate extractor test and the triaxial compression tests was also conducted. By using the rainfall data measured in the site the seepage analysis of unsteady flow was performed with the program of SEEP/W in Geostudio 2007 and stability of the slope was analyzed with SLOPE/W program. Results of analyses show that shear strength of the unsaturated soil increases with the increase of matric suction. And it was also found that the net volumetric stress and the apparent cohesion increased with the matric suction. The seepage analysis of rainfall represents that the increasing rate of negative pore pressure at the zone of large negative pore pressure is appeared to be high even though lower rainfall intensity, but this tendency declines with ground depth. The stability analysis of slope was carried out for the actual plane of failure with the data representing the field condition. The factor of safety thus calculated was about unity (1.0) or just below, which means that the adopted method of analysis is in good agreement with the field condition.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.1-13
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• 2019

The purpose of this study is to examine the effect of soft ground improvement by dynamic replacement with utilizing crushed rock. In order to understand the ground improvement effect when applying dynamic replacement method with crushed rock, the laboratory test and field test were performed. The internal friction angle and apparent cohesion were derived through direct shear test. The dynamic replacement characteristics were identified by analyzing the weight, drop, and number of blows needed for dynamic replacement. Through the field plate bearing test and density test, the bearing capacity and settlement of the improved ground were measured, and the numerical analysis were conducted to analyze the behavior of the improved ground. In this study, it proposes modified soil experimental coefficient(C_DR) to 0.3~0.5 in the dynamic replacement method with crushed rock. Also when applying the dynamic replacement method using crushed rock, the particle size range is less than 100 mm, D₉₀ is less than 80 mm and D₁₅ is more than 30 mm.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.40-47
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• 2016

Instead of metal connector generally used on the structural glued laminated timber rahmen joints, the GFRP reinforced laminated plates combining veneer and GFRP (Glass Fiber Reinforced Plastic) and bonded type GFRP rod were used as the connectors. As a result of moment resistance performance evaluation on the joint part applied with these connectors, the yield moment of specimen using the GFRP reinforced laminated plates and GFRP rod pin was measured 4 % lower in comparison to the specimen (Type-1) using the metal connectors, but the initial rotational stiffness was measured 29% higher. Also, the yield moment and rotational stiffness of the specimen using the GFRP-reinforced laminated plates and wood (Eucalyptus marginata) pin showed were measured 11% and 56% higher in comparison to the Type-1 specimen, showing the best performance. It was also confirmed through the failure shape and perfect elasto-plasticity analysis that it showed ductility behavior, not brittle fracture, from the shear resisting force by the pin and the bonding strength increased and the unification of member was carried out. On the other hand, in case of the specimen bonded with GFRP rod, it was impossible to measure the bonding performance or it was measured very low due to poor bonding.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.4
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• pp.277-282
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• 2014

Recently, much attention has been paid to nonlinear ultrasonic technology as a potential tool to assess hidden damages that cannot be detected by conventional ultrasonic testing. One nonlinear ultrasonic technique is measurement of the resonance frequency shift, which is based on the hysteresis of the material elasticity. Sophisticated measurement of resonance frequency is required, because the change in resonance frequency is usually quite small. In this investigation, the nonlinear electromagnetic acoustic resonance (NEMAR) method was employed. The NEMAR method uses noncontact electromagnetic acoustic transducers (EMATs) in order to minimize the effect of the transducer on the frequency response of the object. Aluminum plate specimens that underwent three point bending fatigue were tested with a shear wave EMAT. The hysteretic nonlinear parameter ${\alpha}$, a key indicator of damage, was calculated from the resonance frequency shift at several levels of input voltage. The hysteretic nonlinear parameter of a damaged sample was compared to that of an intact one, showing a difference in the values.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.559-573
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• 2007

Orthotropic steel decks are manufactured by welding thin plates therefore it is inevitable that there are abundant works of welding process. On connection of transverse rib web, crossing point of longitudinal rib, transverse rib and deck plate and cut-out parts of transverse rib are the significant position of stress concentration because of out of plane and oil-canning deformation caused by longitudinal rib distortion with shear force and distortion. At the current research, the crossing point where the orthotropic steel decks's effect of improving fatigue performance are high, not placing scallop and diaphragm which have same plane with transverse rib placed inside of longitudinal rib at the same time, the reduce effects of stress concentration at the cut-out section and the crossing are high. Especially the installation of the diaphragm causing great effects based on research results to stress concentration appearance reduce effects at the cut-out section, putting radius of curvature of the diaphragm's top and bottom as a target, as a result of carrying out the parametric analysis an optimal diaphragm form that has great effects in fatigue performance came to a conclusion. Also based on optimal diaphragm form, an advantage of the diaphragm optimal setting position for improvement of the fatigue performance came to a conclusion.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.823-829
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• 2002

The composite frame system with reinforced concrete column and steel beam has some advantages in the structural efficiency by complementing the shortcomings between the two systems. The system, however has also a lot of problems in practical design and construction process due to the material dissimilarities. Considering these circumstances, this research is aimed at the development of the composite structural system which enables the steel beams to be connected to the R/C columns with higher structural safety and economy. Basically the proposed connection system is composed of four split tees, structural angles reinforced by stiffener, high strength steel rods, connecting plates and shear plates. The structural tests have been carried out to verify the moment transfer mechanism from beam flange to steel rods or connecting plates through the angle reinforced by siffener. The four prototype specimens have been tested until the flange of beam reached the plastic states. From the tests, no distinct material dissimilarities between concrete and steel have been detected and the stress transfer through wide flange beam - structural angle - high strength steel rod or connecting plate is very favorable.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.271-277
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• 2014

The objective of this study was to determine the effect of the meat from spent laying hen on the shelf-life and physicochemical properties of emulsified sausage. Four types of sausage were made: 0% (Control), 10% (T1), 20% (T2) and 30% (T3) of spent hen meat added. Each sausage type was tested in triplicate. The addition of spent hen meat resulted in decreased crude fat and cooking loss, and increased WHC (water holding capacity), CIE $a^*$ and hardness. Values for crude fat and cooking loss were significantly decreased by the addition of spent laying hen meat relative to the control (P<0.05). Especially, T3 was significantly (P<0.05) decreased compare to other treatment groups. Spent laying hen meat addition had no significantly effects on moisture, crude protein, crude ash, pH, WHC, TBARS (thiobarbituric acid reactive substance) values, shear force, total plate counts (TPC), CIE $L^*$ and $b^*$ values. In conclusion, this study demonstrates that the addition of spent laying hen meat to emulsified sausages tended to improve sausage quality.

• Food Science of Animal Resources
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• v.25 no.4
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• pp.415-422
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• 2005

The pork loin used in this study was obtained from carcass chilled for 24 hours after slaughter and divided into 2 pare. The first part was air packaged and the other part was vacuum packaged, both of which were chilled at $4^{\circ}C$. After 2 days of slaughter, the qualities of air packaged loin chilled for 1 day showed lower drip lose, higher water holding capacity and better sensory texture than the vacuum packaged port (p<0.05). On the other hand, the air packaged loin chilled for 2 days showed lower drip loss and shear force value(SFV), higher Hunter's $a^*$ value, higher amount of taurine and alanine, and better taste, texture, juiciness and palatability than the vacuum packaged pork (p<0.05). However, the air packaged loin chilled for 3 days showed lower hip loss, chewiness SFV, higher amount of VBN $(12.37\;mg\%)$ and total plate count $(2.6\times10^4\;CFU/cm^2)$ than the vacuum packaged pork chilled for the same day (p<0.05). for the same chilling period, there was not significant difference between air and vacuum packaged pork in pH, TBA value, $L^*$ value, $b^*$ value, cooking loss, hardness, springness, cohesiveness, gumminess, total free amino acid contents and cooked meat aroma (p>0.05). Considering all these results, it is recommended that the way of air packaging for the pork with a short storing period should be reconsidered to cut down expenses.

• 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.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.303-312
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• 2007

Steel box girder bridges are being commonly designed for medium-span bridges of span length. Composite truss bridges with steel diagonals instead of concrete webs can be an excellent design alternative, because it can reduce the dead weight of superstructures. One of the key issues in the design of composite truss bridges is the joint structureconnecting the diagonal steel members with the upper and lower concrete slabs. Because the connection has to carry concentrated combined loads and the design provisions for the joint are not clear, it is necessary to investigate the load transfer mechanism and the design methods for each limit state. There are various connection details according to the types of diagonal members. In this paper, the joint structure with group stud connectors welded on a gusset plate is used. Push-out tests for the group stud connectors of were performed. The test results showed that the current design codes on the ultimate strength ofthe stud connection can be used when the required minimum spacing of stud connectors is satisfied. Flexure-shear tests were conducted to verify the applicability of the design provisions for combined load effects to the strength of joint structures. To increase the pullout strength of the connection, bent studs were proposed and utilized for the edge studs in the group arrangement of the joint. The results showed that the details of the joint structure were enhanced. Thereafter, design guidelines were proposed.