• The Korean Journal of Food And Nutrition
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• v.23 no.3
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• pp.419-427
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• 2010

The focus of the current study was to investigate the physicochemical properties of a corn starch-sponge matrix prepared at a low concentration below gel forming by freeze-drying. The effect of variables(starch concentration, heating temperature, and heating hold time) on the physicochemical properties of the samples was analyzed by response-surface methodology. Regression models on the properties of samples such as hardness, springiness, and water solubility index(WSI) showed high correlation coefficients(r>0.95) and significant F values, but regression models for the other properties(swelling power, apparent viscosity, reducing sugar content, and digestibility) showed them to have relatively low significance. Sample hardness of sample showed the highest value at condition of $90^{\circ}C$ and 5%, whereas springiness was at a maximum at $130^{\circ}C$ and 5%. Also, at 1% of starch concentration, mechanical properties were greatly decreased as the relative humidity increased, compared with the 3% and 5%, especially in the hardness of samples. The WSI showed an increasing trend with heating temperature regardless of starch concentration. Overall, the physicochemical properties of freeze-dried corn starch-sponge matrix were influenced much more by starch concentration and heating temperature than by heating hold time. The results of this study show that the basic properties of freeze-dried corn starch-sponge matrix can be used for the specific food applications or as a functional material for its stability.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.163-173
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• 2012

This study covers the nonlinear analysis of anchor head for high strength prestressing strand and presents necessary process in improving the performance of anchor head. The surface of wedge for strand is contacted to the surface of the wedge hole on anchor head when it is fitted into the wedge hole, and the contact condition changes according to the level of load applied through the wedge. In order to analyze detailed behavior, nonlinear material model and contact element were used in analysis. It was found from the analysis that the behavior of anchor head is affected by the interaction with the wedge contacted so that the wedge in FE model should have the same figure as the actual object. Circular array of wedge hole presents better stress distribution than layer array even though the small difference in maximum deformation. Increment of thickness of anchor head and distance of wedge hole also improve the performance of anchor head.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.19-22
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• 1995

A biomechanical study was made to demonstrate the superior mechanical performance of the newly designed Miniplate staple to the conventional Coventry staple in high tibial osteotomy(HTO). Using twenty fresh porcine tibiae, the fixational strengh of the two different types of staple in HTO was compared. To minimize the error due to the specimen-to-specimen individuality, the bone mineral density of the tibiae was measured with a bone densitometry (Dual photon absorptionometer, Luner, USA) and those with $0.8\;{\sim}\;1.2\;gm/cm^2$ at the proximal tibia was used in the biomechanical test. Testing was performed on a material testing system (Autogram ET-5, Shimatzu, Japan) with aid of a commercial data processor (IBM 80386/ ASYST). Using two differant loading modes, 'pull-out' and 'push-out', the maximum resistant force required to release the staple from the substrate bone was recorded. In the pull-out test, ten non-osteotomized specimens were used and the staple was pullout by subjecting an axial tension on the head of the staple inserted. While in the pull-out test where ten tibiae osteotomized in the usual way of HTO were used, the staple was not directly loaded. In this testing, as a mimic condition of the natural knee, the distal part of the specimen tibia was pushed horizontally in order for the staple to be pulled out while the proximal tibia was fixed. The pull-out strength of Coventry staple and miniplate staple were found to be $27.88\;{\pm}\;5.12\;kgf$ and $182.47\;{\pm}\;32.75\;kgf$, respectively. The push-out strength of Coventry staple and miniplate staple were $18.40\;{\pm}\;4.47\;kgf$ and $119.95\;{\pm}\;19.06\;kgf$, respectively. The result revealed that miniplate staple had the pull-out/ push-out strength at least fivetimes higher than Coventry staple. Based on the measured data, it was believed that the newly designed miniplate staple could provide much better postoperative fixation in HTO. The postoerative application of long leg casting may not be needed after HTO surgery.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.39-44
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• 2018

Wideness variation technique is compounded the smooth diffusivity-vibration status of the fulgurate-space realization level (FSRL) on the wideness realization morph. The realization level condition by the wideness realization morph system is associated with the diffusivity-vibration system. As to search a position of the dot situation, we are acquired of the wideness value with constructed-point point by the diffusivity upper structure. The concept of realization level is composed the reference of fulgurate-space level for variation signal by the wideness vibration morph. Further displaying a smooth variation of the FSRL of the maximum-minimum in terms of the diffusivity-vibration morph, and wideness position vibration that was the a wideness value of the far variation of the $Wid-rm-FA-{\alpha}_{MAX-MIN}$ with $23.24{\pm}3.37units$, that was the a wideness value of the convenient variation of the $Wid-rm-CO-{\alpha}_{MAX-MIN}$ with $7.83{\pm}1.32units$, that was the a wideness value of the flank variation of the $Wid-rm-FL-{\alpha}_{MAX-MIN}$ with $2.99{\pm}0.51units$, that was the a wideness value of the vicinage variation of the $Wid-rm-VI-{\alpha}_{MAX-MIN}$ with $0.51{\pm}(-0.01)units$. The diffusivity vibration will be to evaluate at the smooth ability of the diffusivity-vibration morph with constructed-point by the wideness realization level on the FSRL that is displayed the fulgurate-space morph by the realization level system. Diffusivity realization system will be possible to control of a morph by the special signal and to use a wideness data of diffusivity vibration level.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.377-380
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• 2008

The material and mechanical properties in the high temperature area of 40 to 100 MPa high strength concrete structural member was identified based on mixing of fiber cocktail and the structural element fire behavior simulation through the finite element analysis method (ABAQUS) was interpreted. The results are as follows. First, it was interpreted that the test specimen with concrete fiber cocktail mixed was more controllable in the maximum shrinkage than the one with concrete fiber cocktail not mixed the controllable range was about 25% to 55%. This means that shrinkage is controllable through mixing of fiber cocktail for the high strength concrete columns. Second, this study didn't consider the explosive spalling by the pore pressure within high strength concrete. If the properties for the pore pressure within high strength concrete is considered and database by strength and by inner temperature of various high strength concrete and steel materials are established in the future, it is interpreted that the technical foundation will be laid for performance based design of fire resistant construction.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.147-155
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• 1996

Floating Zone Image furnace with halogen lamps as heat source has been made and applied to the growth of high-Tc superconductor Bi2Sr2CaCu2O8. The manufactured crystal growth equipment is composed of holder unit for setting the halogen lamps at the focal point of the elliptical mirror, image furnace with maximum temperature of 1800℃ with 1kW halogen lamps, cooling unit, feeding unit for supplying source material to the molten zone, pulling unit for crystal growth, and the control unit in the range of 2mm/hr -40 mm/hr vertical movement and 15rpm - 12rpm rotation. Bi2Sr2CaCu2O8 fibers have been grown with 300W halogen lamps and characterized with XRD, SEM and EDS. The growth condition was air atmosphere, growth speed 3∼4mm/hr, rotation speed of upper and lower part 20∼25 rpm. The fiber was composed of 20∼25 rpm matrix phase and secondary phases such as (Sr,Ca)CuO2 and (Sr,Ca)2CuO3.

• Journal of Microbiology and Biotechnology
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• v.16 no.4
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• pp.597-604
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• 2006

In order to extend the shelf-life of packaged or coated foods, an antibacterial edible film containing 1.8% of BLS was developed from the defatted corn germ meal, which had been fermented with Bacillus subtilis under the optimum condition of pH 7.0-7.5 and $33^{\circ}C$ for 33 h. Water vapor permeability of the fermented film $(88.3mg/cm^2\;h)$ was higher than those of the normal corn germ films $(75.8mg/cm^2\;h)$. Protein solubility of the fermented film was also higher than ordinary corn germ film at the pH range of 3-10. The fermented corn germ film had higher tensile strength and lower % elongation (elongation rate) than the ordinary corn germ film. The antimicrobial activity of the film was more than 50% of the maximum activity after film production with heat treatment at $90^{\circ}C$ and pH adjustment to 9. When the corn germ protein film with bacteriocin-like substance was applied on the mashed sausage media containing E. coli, the bacterial growth inhibition was higher than the ordinary corn protein film.

• Journal of Applied Biological Chemistry
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• v.43 no.1
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• pp.25-30
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• 2000

The main form of nitrogen fertilizer applied to lowland rice is urea, but little is known about its transport in waterlogged soil. This study was conducted to investigate the transport of urea in waterlogged soil column using WAVE (simulation of the substances Water and Agrochemicals in the soil, crop and Vadose Environment) model which includes the parameters for urea adsorption and hydrolysis, The adsorption distribution coefficient and hydrolysis rate of urea were measured by batch experiments. A transport experiment was carried out with the soil column which was pre-incubated for 45 days under flooded condition. The urea hydrolysis rate (k) was $0.073h^{-1}$. Only 5% of the applied urea remained in soil column at 4 days after urea application. The distribution coefficient ($K_d$) of urea calculated from adsorption isotherm was $0.21Lkg^{-1}$, so it was assumed that urea that urea was a weak-adsorbing material. The maximum concentration of urea was appeared at the convective water front because transport of mobile and weak-adsorbing chemicals, such as urea, is dependent on water convective flow. The urea moved down to 11 cm depth only for 2 days after application, so there is a possibility that unhydrolyzed urea could move out of the root zone and not be available for crops. A simulated urea concentration distribution in waterlogged soil column using WAVE model was slightly different from the measured concentration distribution. This difference resulted from the same hydrolysis rate applied to all soil depths and overestimated hydrodynamic dispersion coefficient. In spite of these limitations, the transport of urea in waterlogged soil column could be predict with WAVE model using urea hydrolysis rate (k) and distribution coefficient ($K_d$) which could be measured easily from a batch experiment.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.10-17
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• 2020

The structural reliability assessment can be used to improve the reliability in the asset integrity management of the pipeline by using a geometric variation, mechanical characteristics, load change and operating condition as evaluation factors. When evaluating structural reliability, the failure probability of the natural gas pipe is evaluated by the relationship of the resistance of the pipe material to external loads. The failure probability of the natural gas pipe due to the combined stresses such as the internal pressure, thermal stress and bending stress was evaluated by using COMREL program. When evaluating the failure probability of the natural gas pipe, a buried depth of 1.5 to 30 m, a wheel load of 2.5 to 20 ton, a temperature difference of 45℃, an operating pressure of 6.86MPa, and a soil density of 1.8 kN/㎥ were used. The failure probabilities of the natural gas pipe were evaluated by the Von-Mises stress criterion as the maximum allowable stress criterion under the combined stresses.

• Smart Structures and Systems
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• v.19 no.1
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• pp.39-46
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• 2017

Finite element model updating is very effective procedure to determine the uncertainty parameters in structural model and minimize the differences between experimentally and numerically identified dynamic characteristics. This procedure can be practiced with manual and automatic model updating procedures. The manual model updating involves manual changes of geometry and analyses parameters by trial and error, guided by engineering judgement. Besides, the automated updating is performed by constructing a series of loops based on optimization procedures. This paper addresses the ambient vibration based finite element model updating of long span reinforced concrete highway bridges using manual model updating procedure. Birecik Highway Bridge located on the $81^{st}km$ of Şanliurfa-Gaziantep state highway over Firat River in Turkey is selected as a case study. The structural carrier system of the bridge consists of two main parts: Arch and Beam Compartments. In this part of the paper, the arch compartment is investigated. Three dimensional finite element model of the arch compartment of the bridge is constructed using SAP2000 software to determine the dynamic characteristics, numerically. Operational Modal Analysis method is used to extract dynamic characteristics using Enhanced Frequency Domain Decomposition method. Numerically and experimentally identified dynamic characteristics are compared with each other and finite element model of the arch compartment of the bridge is updated manually by changing some uncertain parameters such as section properties, damages, boundary conditions and material properties to reduce the difference between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of long span highway bridges. Maximum differences between the natural frequencies are reduced averagely from %49.1 to %0.6 by model updating. Also, a good harmony is found between mode shapes after finite element model updating.