• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.45-51
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• 2020

The poisson's ratio was obtained from the effective vertical stress and horizontal stress of consolidation-undrained test. It was analyzed void ratio verse poisson's ratio. At the result, the effective friction angle was increase with relative density increased, was decreased the poisson's ratio. The empirical equation of void ratio and poisson's ratio was showed very high correlation r²=0.846. The empirical equation was showed that the smaller the void ratio in the fine grained soil than granular soil. In the case of 0.85 times the correlation analysis equation of granular and fine grained soil, the experimental results were shown very similarly. In especially, the poisson's ratio prediction results was shown within 5% of the error range, was revalidation 0.85 times the correlation analysis equation using the void ratio. In this study, correlation analysis equation of the granular and fine grained soil was more reliability of the poisson's ratio prediction results apply to the void ratio than dry unit weight.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1495-1507
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• 2022

The improvement of thermal-hydraulic analysis techniques is essential to ensure the safety and reliability of nuclear power plants. The one-dimensional two-fluid model has been adopted in state-of-the-art thermal-hydraulic system codes. Current constitutive equations used in the system codes reach a mature level. Some exceptions are the partition method of wall friction in the momentum equation of the two-fluid model and the interfacial drag force model for a horizontal two-phase flow. This study is focused on deriving the partition method of wall friction in the momentum equation of the two-fluid model and modeling the interfacial drag force model for a horizontal bubbly flow. The one-dimensional momentum equation in the two-fluid model is derived from the local momentum equation. The derived one-dimensional momentum equation demonstrates that total wall friction should be apportioned to gas and liquid phases based on the phasic volume fraction, which is the same as that used in the SPACE code. The constitutive equations for the interfacial drag force are also identified. Based on the assessments, the Rassame-Hibiki correlation, Hibiki-Ishii correlation, Ishii-Zuber correlation, and Rassame-Hibiki correlation are recommended for computing the distribution parameter, interfacial area concentration, drag coefficient, and relative velocity covariance of a horizontal bubbly flow, respectively.

• Journal of Power System Engineering
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• v.20 no.3
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• pp.57-63
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• 2016

This paper presents the experimental result and theoretical analysis result to investigate the correlation between the operating force, angle and locking torque for vehicle hood frame. Also, we derived the experimental equation that using the results for experiment and theory. The hood frame is switching-devices used for opening and closing the vehicle hood. It needs the correlation data between locking torques of each joint, operating force and angle of hood frame. The correlation data for torque and reaction force of hood frame obtained through experiment and theory analysis. Finally, the experimental equation of the locking torque prediction for the hood frame is derived.

• Journal of Environmental Health Sciences
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• v.16 no.2
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• pp.55-61
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• 1990

Laboratory methods commonly used today are biochemical oxygen demand, chemical oxygen demand, and total organic carbon. Establishment of constant relationships among the various measures of organic content depends primarily on the nature of the wastewater and its source. Of all the measures, the most difficult to correlate to the others is the BODs test, because of the problems associated with biological tests. The results were summarized as follwos, 1. For typical municipal wastes, however, the SBOD$_{5}$/SCOD$_{cr}$ ratio varies from 0.14 to 0.34(mean 0.21), SBOD$_{5}$/STOC ratio varies from 0.35 to 1.19(mean 0.69) 2. Correlation analysis between the SBOD$_{5}$ and SCOD$_{cr}$ gave good correlation coefficient r = 0.903 and the equation Y = 3.756X + 16,221 was obtained. 3. The correlation between the SBOD$_{5}$ and STOC was well presented with equation : Y = 1,070X + 7,637, and also correlation coefficient r = 0.821 4. The correlation between the SCOD$_{cr}$ and STOC was well presented with equation : Y = 0.256X +5.513 and also correlation coefficient r = 0.816. 5. Because of the rapidity with which the TOC test can be conducted, it is anticipated that more use will be made of these tests in the future.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1401-1406
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• 2003

Performance of two vapor pressure correlation equations in a polynomial expression is compared. These are the Wagner-type equation and the Inverted form equation. The equations are fitted to correlate the data in the ASHRAE tables and from NIST Chemistry WebBook for 17 pure substances. Some observations on the exponents in the two polynomial equations are made, which results in a proposal of a new closed form vapor pressure equation. The new equation yields the accuracy comparable to that of the Wagner-type equation and better than that of the Inverted form equation.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.373-379
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• 2005

A few correlation equations of the saturated liquid density are reviewed and a new equation is proposed. Performance of each equation is examined using the data listed in the ASHRAE table for 22 pure substance refrigerants. The new four-parameter equation yields an average absolute deviation of 0.03% for 22 refrigerants. Performance of the new four-parameter equation is found to be equivalent to those of the existing equations such as Hou-Martin equation(0.03%) and Iglesias-Silva-Hall equation(0.08%).

• International Journal of Safety
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• v.10 no.1
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• pp.5-9
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• 2011

Two popular activity coefficient models, Wilson and NRTL equations have been used to correlate the published flash point data on the n-propanol + propionic acid and n-butanol + propionic acid systems through the optimization method. The results of these correlation were compared with the results calculated by Raoult's law. The optimization method were found to be better than those based on the Raoult's law. The optimization method based on the Wilson equation described the published data more effectively than was the case when the optimization method was based upon the NRTL equation.

• The Journal of Korean Medicine
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• v.25 no.4
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• pp.43-50
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• 2004

Objective : Obesity is associated with degenerative arthropathy giving stress on joints. It also amplifies loads of weight bearing joints by changing the gravity line of the body. Our aim is to investigate the correlation between obesity and lumbar lordosis in obese pre-menopausal Korean females. The hypothesis was tested that there is a correlation between obesity and lumbar lordosis. Methods : A cross-sectional evaluation of 44 Females (baseline age 30.77 ± 6.46) with BMI 31.53 ± 3.82 (kg/㎡) was done. Body composition was measured using bio-impedance analysis (BIA), and anthropometry was done by the same observer. A lateral whole spine X-ray was taken in standing position to measure the lumbar lordotic angle (LLA), Ferguson angle (FA) and lumbar gravity line (LGL). A Pearson correlation was used to measure the correlation between obesity and lumbar lordosis (SPSS 10.0 for windows). Results : Body mass index (BMI kg/㎡) had a negative relationship with LLA((equation omitted)=-0.469), FA((equation omitted) =-0.347) and LGL((equation omitted)=-0.389). Body fat rate had a negative relationship with LLA only(γ=-0.385). Waist circumference had a negative relationship with LLA((equation omitted)=-0.345) and LGL((equation omitted)=-0.346). WH ratio had no relationship with lumbar lordosis. Conclusion : These data show that obesity is related to mechanical structures, such as lumbar lordosis. BMI was the most useful index, which reflects a change of mechanical structure of lumbar, more than other variables in this study.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.764-769
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• 1994

This study was performed to obtain fast, consistant and reliable estimation system of bacterial counts of raw milk, which effectively related to the quality of sanitaion and the condition of production at the farm. This study compared regression equation and correlation coefficient relationship between standard plate counts and data of Malthus conductance method for the detection time of total, psychrotrophs, coliform bacterial counts in raw milk. Regression equation (RE) between conductance detection time (Y) and total bacterial log counts (X) was Y=18.27651 - 2.07550X, with correlation coefficient -0.95(n=201). In coliform, RE was Y=9.320848 - 1.15598X with correlation coefficient -0.90 (n=207). Psychrotrophs had the RE of Y=29.96008-3.02487 with correlation coeffecient -0.9 (n=201). This conductance method gave results more quickly and was less labor-intensive than traditional standard plate count method.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.629-633
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• 2005

In the reversed-phase chromatography, the retention time of sample was investigated based on the molecular structure of compound. Several descriptors that were related to retention factors were selected, and then the values of descriptors were calculated with several softwares. The effect of retention factor was measured with calculated values, and the results were obtained that each descriptors of molecular structure of compound have different effect on the retention factor. Therefore, the empirical equation for seven types of descriptors considered was obtained, and it has high values of correlation coefficient. Furthermore, the experimental data and calculated values have good agreement.