• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.415-422
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• 2012

This paper analyzed seventy eight previous test results to evaluate bond strength of Near Surface-Mounted (NSM) FRP and prediction formulas previously proposed by researchers. The results showed that the most reliable bond strength prediction was the one proposed by Seracino, who considered the shape coefficient (ratio of width-thickness) and stiffness of FRP. However, the equation tended to underestimate the bond strength, especially serious when FRP bond length was relatively short, because the equation did not consider the effect of bond length. Based on the analysis of previous test results, the relation between bond length and bond strength and the group effect due to close proximity of FRPs were determined. Based on the findings, the Seracino's formula was modified and it's applicability was evaluated. The result showed that the suggested formula can be used effectively to predict the bond strength of NSM FRP.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.309-315
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• 2014

Summer cabbages in an alpine area are very sensitive to the fluctuations in supply and demand. Yield variability due to weather conditions dictates the market fluctuations of cabbage price. This study reports an empirical relationship based on weather conditions to estimate the growth and harvestable biomass of cabbages, factors that are critical for supply of summer cabbages. Based on experimental results testing sowing date effects over the two years from 1997 to 1998, a logistic equation was parameterized to predict leaf area expansion of summer cabbages. This logistic model for leaf area expansion was then combined with an empirical allometric relationship to predict total biomass. The final equation for estimating fresh weight accumulation of Chinese cabbage is given by: $$Fresh\;weight=3500/(1+{\exp}(5.175-1.153{\times}(6/(1+{\exp}(6.367-0.0064{\times}PHU)))))$$ Where PHU is potential heat units ($^{\circ}C$). The model performance was tested using weather data from 2003 to 2006 to predict fresh harvestable biomass. Overall the model performance was satisfactory with the correlation efficient ranging between 0.89 and 0.94 for each year.

• Fire Science and Engineering
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• v.25 no.3
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• pp.113-118
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• 2011

The flash point is an important indicator of the flammability of a chemical. The minimum flash point behaviour (MFPB) is exhibited when the flash point of a mixture is below the flash points of the individual components. The identification of this behaviour is critical, because a hazardous situation results from taking the lowest component flash point value as the mixture flash point. In this study, the flash points for the n-butanol + n-decane and n-octane + n-propanol systems which exhibit MFPB, were measured by Tag open-cup apparatus. The experimental data were compared with the alues calculated by the Raoult's law, the van Laar equation and the Wilson equation. The calculated values based on the van Laar and Wilson equations were found to be better than those based on the Raoult's law. It was concluded that the van Laar and Wilson equations were more effective than the Raoult' law at describing the activity coefficients for non-ideal solution such as the n-butanol + n-decane and n-octane + n-propanol systems. The predictive curve of the flash point prediction model based on the Wilson equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the van Laar equation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.74-82
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• 1982

In the previous study, we have reported the effect of lowering water activity of sodium chloride, sugars and polyols. In this study, water activity($a_w$)of various model Preparations of Kamaboko was measured and ability of lowering $a_w$ of starch, glycine and sodium lactate was discussed. In addition, the aw measurements were also compared to the predicted values of au which were derived from the equation of Raoult's law and the linear slope method by Sloan ana Labuza. The effect of starch on lowering $a_w$ was very low, and glycine was more effective than starch. Sodium lactate was shown to be the most effective among humectants examined. When it was added by $7.5\%$, the $a_w$ of model Kamaboko A was reduced to 0.93-0.94. Generally, prediction by the equation of Raoult's law turned out to be useful for determining $a_w$ lowering effect of humectants, excepting sodium chloride and sodium lactate. The equation of regression derived from the least squares could be applied to Predicting au in the model Kamaboko.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.107-114
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• 1998

The solubilities of $CO_2$ in 20wt% and 30wt% aqueous AMP solution were obtained from experiments at 40, 50, 60, 70, $80^{\circ}C$. Using the modified Kent-Eisenberg model, equilibrium constants and correlations were determined from the regression of experimental results of 30wt% aqueous AMP solution. There were good agreements between the predicted $CO_2$ solubilities in 20wt% aqueous AMP solution and experimented values. The prediction was conducted at the condition in the literature and the predicted values calculated from the model and correlations which were obtained from this work agree well with the prediction from Deshmukh-Mather model. Thus, the modified Kent-Eisenberg model and correlated equations suggested by this work, resonably well represent vapor-liquid equilibrium of $CO_2$ with aqueous AMP solution. The calculation of chemical species concentration in the liquid phase was performed uslng equilibrium model and from this calculation, we confirm that good absorption capacity is due to the formation of unstable carbamate. Heat of solution(${\Delta}Hs$) was calculated from the solubility data using the Gibbs-Helmholtz equation.

• Progress in Medical Physics
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• v.4 no.1
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• pp.29-39
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• 1993

Electron beams have found unique and complementary used in the treatment of cancer, but it's very difficult to delineate dose distribution, because of multi-collisions. Numerical solution is more usefull to describe electron distributed in tissue. A semi-empirical eqution is given for the dose at any point at various depths in water. This equation is a modificated model which was based on solutions of a general age diffusion equation. Parameters have been calulated from electron beams data with energies 6～18MeV form a LINAC for use in computerised dosimetry calculations. The depth doses and isodose curves are predicted as a function of the practical range, source skin distance and field size. Depth dose accuracy have been achieved 2% above 50% depth dose and 5% at lower doses, relative to maximum dose. Also, the shape of the isodose curves with the constrictions at higher dose and bulging ot lower values are accurately predicted. Computer calculated beams have been used to generate ever isodose distribution for certain clinical situations.

• Water for future
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• v.25 no.3
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• pp.115-124
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• 1992

The peak flood discharge at a downstream station and the flood travel time between a pair of dams due to a specific flood release from the upper reservoir are computed using a hydraulic river channel routing method. The study covered the whole reservoir system in the Han River. The computed peak flood discharges and the travel times between dams were correlated with the duration and the magnitude of flood release rate at the upstream reservoir, and hence a multiple regression model is proposed for each river reach between a pair of dams. The peak flood discharge at a downstream location can be converted to the peak flood stage by rating curve. Hence, the proposed regression model could be used to forecast the peak flood stage at a downstream location and the flood travel time between dams using the information on the flood release rate and duration from the upper dam.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.8
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• pp.734-739
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• 2008

In this study, the nonlinear mechanical behavior of flexible textile composites was predicted by two-step analyses: micromechanics and mesomechanics. The effective material properties for fiber tows of flexible textile composite lamina were calculated in micromechanics, which were then used to calculate the effective tensile stress-strain curve of flexible textile composites in mesomechanics. A user defined material algorithm was developed and inserted in ABAQUS to account for the geometric non-linearity due to the large rotation and shear deformation of fiber tows in mesomechanics. It was found that the stress-strain behavior of flexible textile composites exhibited significant non-linearity. The effective tensile modulus agreed well with the test result.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.10
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• pp.24-31
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• 2006

In this paper, mechanical behavior of unidirectional composites with flexible matrix was predicted by geometrical non-linear finite element analysis. Two typical idealized unit cells of square and hexagonal fiber arrays were modeled and these were subjected to different loadings. The stress-strain behavior of composites was predicted from which the effective properties were calculated. The hyperelasticity of polyurethane matrix was considered using Mooney-Rivlin model. In result, the stress-strain behavior of flexible composites shows non-linearity, especially it is remarkable under transverse normal and shear loading conditions. In this cases, there are great difference between square and hexagonal fiber array models.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.789-798
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• 1991

본 연구에서는 원통형 구조물의 진동해석을 위하여 통계에너지 분석방식(st- atistical energy analysis:SEA)이 사용되었다. SEA는 4개의 물리적 변수인 구조물 질량(Mi), 주파수대역에 존재하는 고유진동수(Ni), 내부손실계수(internal loss fact- or) 및 상호손실계수(coupling loss factor)를 이용하여 구조물의 진동수준과 구조물 상호간의 에너지 교환을 해석하는 방법으로서 비록 넓은 주파수 범위에 걸쳐 정확한 진동예측을 하기에는 어느정도 오차가 예상되는 단점이 있으나 진동해석이 용이하고 복잡한 계산을 필요로 하지 않기 때문에 대형구조물의 진동해석에 많이 사용되고 있 는 기법이다. 따라서 연구의 대상인 원통형 구조물의 고유진동수를 예측하기 위하여 일차적으로 반경에 의한 곡률영향을 배제시킨 평판에 대한 분석이 시도되었다. 이와 함께 주어진 주파수 대역에 걸쳐 평판및 원통형 구조물의 고유진동수의 차이를 비교하 였다.그결과로부터 원통형 구조물에 대한 고유진동수 계산식을 평판구조물의 굽힘 강성과 곡률반경으로 야기되는 표면응력에 의한 함수로 표현하였다.