• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.569-577
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• 2015

Recently, the concept of seismic design has changed from prescriptive to performance based design. For the performance based design with the specified target performance of the structure, it is necessary to execute the inelastic structural analysis to predict precisely the actual behavior of the structure. To address this issue, the seismic performance of the 5-story RC moment-resisting frames designed in accordance with KBC2009 is evaluated through push-over analysis and economic analysis is conducted focused on the direct construction costs. The results show that the ordinary and the intermediate moment-resisting frame are evaluated to meet the required performance design criteria and that the direct construction costs of the two frames are similar. However, although the special moment-resisting frame designed with strong column-weak girder philosophy satisfies the required performance design criteria, the direct construction cost is uneconomical compared with other frames. Therefore, although the intermediate moment-resisting frame of design category D is prohibited in IBC2012, the ordinary and the intermediate moment-resisting frame are estimated to be more reasonable than the special moment-resisting frame for the design of 5-story RC moment-resisting frame.

• Food Science and Preservation
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• v.6 no.2
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• pp.161-166
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• 1999

In order to increase the Korean wheat-cultivators' incomes as well as to promote their consumptions, the native wheat of 11 varities (Chokwangmil, Geurumil, Eunpamil, Tapdongmil, Woorimil, Olgeurumil, Alchanmil , Gobunmil, Geungangmil Seodunmil and Suwon 265) were investigated on dough properties to compared with those of two imported wheat varieties, DNS (Dark Northern Spring Wheat) and ASW (Austrlian Standard White). In dough stickiness, Chokwangmil was highest as 81.78, and the mean value of native wheat was 53.98 g. ASW and DNS showed the stickiness values of 58.7 g and 52.9 g, respectively. Tapdongmil was highest in the tensile tone of dough as 87.6 g. In the texture test, the highest elasticity, gumminess, firmness and chewiness were observed in Woorimil as values of 0.980, 1,022.8, 1,562.7 and 1,001.9, respectively, while the highest cohesiveness and adhesiveness were obtained from Suwon 265 and Geurumil, respectively, as 0.710 and -609.4. In amylogram properties, the initial gelatinization temperature was ranged from 65$^{\circ}C$ to 69$^{\circ}C$, and maximum, minimum and final viscosities were highest in Woorimil as 1,140, 1,100 and 1,730 BU, respectively. In farinogram, water absorption rate was highest in Suwon 265 as 65.1%, which required the longest dough arrival time of 3.5 min. Dough developing time, weakening and stability were longest in Gobunmil as 9.7. 32.1 and 29.9 min., respectively. The resistance of dough was highest in Olgeurumil as 110 BU.

• Magazine of the Korea Concrete Institute
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• v.2 no.2
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• pp.81-92
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• 1990

Concrete, a mixed material, has heterogeniety, anisotrophy and nonlinearity. Therefore, in its 'racture analysis, it is more reasonable to evaluate its fracture toughness by applying the concept of 'racture mechanics rather than the strength concept. Up to the present the concepts of fracture mechanics which were applied to concrete have been divided into two main classes. The one is the concept of linear elastic fracture mechanics and the other is the concept of elastic-plastic fracture mechanics. But it has been pointed out that there are many problems and irrationalities in applying the concept of linear elastic fracture mechanics to concrete. In this study, the J -integral method and the COD method mainly used in the analysis of nonlinear fracture mechanics, were introduced and the three point bending test was carried out for investigating the effects of the variation of the maximum aggregate size and notch depth on the fracture behavior and the crack growth of concrete, and the relationships of fracture energy and crack opening displacement. According to the results of this study the more the maximum aggregate size and the notch depth increased, the more the nonlinearity of load-deflection behavior was remarkable. The increase of the coarse aggregate size created the more ductility of concrete. Thus concrete showed the more stable fracture. As for the path of the crack growth, the more the coarse aggregate size increased, the more it was irregulary deviated from the straight line but it was not almost affected by the variation of the notch depth. Also, the fracture energy increased according as the coarse aggregate size increased and the notch depth decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.6
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• pp.872-879
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• 2010

Textured vegetable protein (TVP) was fermented by the solid-state fermentation using Bacillus subtilis HA and biologically active compounds were produced by fermentation for 7 days. The longer fermentation time resulted in the color change of fermented TVP with strong dark red and yellow color. Melanoidin production rapidly increased until fermentation for 48 hr, but did change afterwards. The 70% ethanol extract of TVP fermented for 24 hr showed higher DPPH radical scavenging effect with $IC_{50}$ of 0.99 mg/mL but longer fermentation did not increase its activity. Also, 70% ethanol extract of TVP fermented for 72 hr indicated higher ABTS radical scavenging effect with $IC_{50}$ of 1.68 mg/mL. Consistency index in TVP fermented for 48 hr was the highest values with 7.89 $Pa{\cdot}s^n$. Viscoelastic properties of TVP fermented for 48 hr were maximally enhanced, and viscous value (G") is higher than the elastic value (G'). The $\gamma$-polyglutamic acid (PGA) content was increased by increasing fermentation time with 37.72% of $\gamma$-PGA at 168 hr. However, levan content and molecular weight of PGA were decreased with increasing fermentation time from 7.83% to 3.91% and 1649.3 kDa to 1286.8 kDa, respectively.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.266-272
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• 1997

In order to investigate the compression and decompression properties of cucumber, radish, garlic, ginger and potato, edible parts of samples were prepared to size of ${\Phi}\;5\;mm{\times}H\;5\;mm$, and force deformation relationship during application and removal of force were observed. Compositions of sample and cell characteristics were measured, and correlations between them were investigated. Deformation rate was large in initial stage of compression and decreased afterward, but the reverse trends were observed in the decompression. The time and deformation to 9 N were large of 5.30 sec and 1.344 mm in potato, and small of 4.62 sec and 0.896 mm in garlic, respectively. Force(y)-deformation(x) curve between compression and decompression were clearly showed hysteresis loop and relationship of x and y were as follows: y=esp (a+b log(x)). The maximum work was $3.888{\sim}5.099{\times}10^{-3}\;J$ for potato in compression and $2.09{\times}10^{-3}\;J$ for garlic in decompression. Irrecoverable work were large as $77{\sim}96%$ in cucumber, radish and potato, and small as $36{\sim}42%$ in garlic. Compression deformation were large as $1.016{\sim}1.344\;mm$ in potato, and small as $0.656{\sim}0.896\;mm$ in garlic. Degree of elasticity were large as $0.756{\sim}0.777$ in garlic, and small as $0.301{\sim}0.465$ in radish and potato. Compression and decompression characteristic values were showed high correlation with moisture, viscosity of juice, ceil size, density and regularity.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.5
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• pp.473-478
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• 2009

The purpose of this study is to evaluate the behaviour of the plastic deformed zone at crack tip on the standard Charpy specimens which were taken from the multi-passed weld block of the pressure vessel steel. Notch was machined on the standard Charpy test specimens and pre-crack which was located around the fusion line was made under the repeat load. Four point bend and acoustic emission tests were carried out simultaneously. The size of plastic region at crack tip was calculated using stress intensity factor. Relationships between characteristics of acoustic emission and plastic zone size at crack tip were discussed through the cumulative AE energy. Regardless of the specimens, AE signals were absent within the elastic region almost and most of AE signals were produced at the plastic deformation region from yield point to the mid-point between yield and maximum load. More AE signals for the weldment were produced compared with the base-metal and PWHT specimen. Relations between plastic deformed zones at crack tip and cumulative AE energy for the weldment and PWHT specimen were different quietly from the base-metal. Besides, number of AE counts for the weldment was the larger than those of the base-metal and PWHT specimen.

• 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.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.354-360
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• 2016

We investigated the quality and antioxidant activities of sponge cake prepared containing 1-5% of green tea powder (GT). The water content in the cake increased with an increase in the amount of GT added. Although the hardness and springiness of the rice sponge cake increased, the adhesiveness decreased with increasing the level of GT. The cohesiveness, chewiness, and resilience of the rice sponge cake with GT were similar to those of the control. Chromaticity determination revealed that lightness, redness, and yellowness of the crust decreased with increasing GT content. Total polyphenol and flavonoid contents increased proportionally with increasing GT level. Antioxidant activity, measured by DPPH and ABTS radical scavenging as well as reducing power activities, was significantly higher in the rice sponge cake with GT than in the control. Sensory evaluation determined that addition of 1-3% GT to the rice sponge cake maintained the color, taste, texture, flavor, and overall acceptance similar to that of the control.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.4
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• pp.389-393
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• 2017

Purpose: The aim of this study is to evaluate the flexural strength of flexible resins and the flexibility of different resin splint (RS) systems in comparison with resin wire splint (RWS) system. Materials and methods: Three different resin materials (G-aenial flo, GA, GC; Superbond, SB, Sun medical; G-fix, GF, GC) were tested flexural strength test in accordance with ISO-4049:2000. For the flexibility test of splint systems, a artificial model with resin teeth was used to evaluate three types of resin splint systems (GA, SB, and GF) and one resin wire splint system. The left central incisor was simulated 'injured teeth' with third degree mobility. Three consecutively repeated measurements of periotest value were taken in horizontal direction, before and after splinting to access tooth mobility. The splinting effect was calculated through the periotest value. Differences were evaluated through One-way Anova and Tukey HDS post-hoc tests for pair-wise comparison (${\alpha}=.05$). Results: Although GA group showed significant higher flexural strength than SB and GF groups, all of three different resin splint systems produced a significantly higher and rigid splinting effect compared with 016" resin-wire splint system (P < .05). Conclusion: Within the limits of an in vitro study, it can be stated that resin splint systems are too rigid and may not be acceptable to treat tooth avulsion.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1603-1610
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• 2012

The effects of moisture content on the physical properties of cereal extrudates were investigated. Cereal flours (rice, wheat, corn, barley, and oat) were extruded at a barrel temperature of $130^{\circ}C$, feed rate of 120 g/min, and various moisture contents (20, 22.5, 25, 27.5, and 30%). Proximate content, expansion index, specific length, bulk density, breaking strength, apparent elastic modulus, water absorption index (WAI), water solubility index (WSI), specific mechanical energy (SME) input, paste viscosity, and color values were analyzed. Expansion ratio of extruded corn flour was higher than that of other extrudates at low moisture content. Bulk density, specific length, and elastic modulus in all cereals decreased with an increase in moisture content. The WAI increased with an increase in moisture content, whereas WSI decreased. SME input of extruded corn flour was higher than those of other cereal flours at lower moisture content, whereas that of oat flour extrudate was lower than those of other cereals at higher moisture content. Lightness of extruded rice flour was lighter than those of other cereals while that of extruded barley flour was darker.