• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1120-1130
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• 2020

The CREOLE experiment performed In the EOLE critical facility located In the Nuclear Center of CADARACHE - CEA have allowed us to get interesting and complete experimental information on the temperature effects in the light water reactor lattices. To analyze these experiments with accuracy an elaborate calculation scheme using the Monte Carlo method implemented in the MCNP6.1 code and the ENDF/B-VII.1 cross section library has been developed. We have used the ENDF/B-VII.1 data provided with the MCNP6.1.1 version in ACE format and the Makxsf utility to handle the data in the specific temperatures not available in the MCNP6.1.1 original library. The main purpose of this analysis is the qualification of the ENDF/B-VII.1 nuclear data for the prediction of the Reactivity Temperature Coefficient while ensuring the ability of the MCNP6.1 system to model such a complex experiment as CREOLE. We have analyzed the case of UO₂ lattice with 1166 ppm of boron in ordinary water moderator in specified temperatures. A detailed comparison of the calculated effective multiplication factors with the reference ones [1] in room temperature presented in this work shows a good agreement demonstrating the validation of our 3D calculation model. The discrepancies between calculations and the differential measurements of the Reactivity Temperature Coefficient for the analyzed configuration are relatively small: the maximum discrepancy doesn't exceed 1,1 pcm/℃. In addition to the analysis of direct differential measurements of the reactivity temperature coefficient performed in the poisoned UO₂ lattice configuration, we have also analyzed integral measurements in UO₂ clean lattice configuration using equivalency of the integral temperature reactivity worth with the driver core fuel reactivity worth and soluble boron reactivity worth. In this case both of the ENDF/B-VII.1 and JENDL.4 libraries were used in our analysis and the obtained results are very similar.

• Progress in Medical Physics
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• v.22 no.2
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• pp.92-98
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• 2011

This study is to keep the accuracy and stability of the output dose evaluations for linear accelerator photon beams by using the air ionization chambers (TM31010, 0.125 cc, PTW) through the Task Group 51 protocol. The absorbed dose to water calibration factor $N_{dw}{^{Co-60}}$ was delivered from the air kerma calibration factor $N_k$ which was provided from manufacture through SSDL calibration for determination of output factor. The ionization chamber of TM31010 series was reviewed the calibration factor and other parameters for reduce the uncertainty within ${\pm}2%$ discrepancy and we found the supplied $N_{dw}{^{Co-60}}$ which was derived from Nk has shown a -2.8% uncertainty compare to that of PSDL. The authors provided the program to perform the output dosimetry with TG-51 protocol as it is composed same screen of TG-51 worksheets. The evaluated dose by determination of output factor delivered to postal TLD block for comparison the output dose to that of MDACC (RPC) in postal monitoring program. The results have shown the $1.001{\pm}0.013$ for 6 MV and $0.997{\pm}0.012$ discrepancy for 15 MV X rays for 5 years followed. This study shows the evaluated outputs for linear accelerate photon beams are very close to that of international output monitor with small discrepancy of ${\pm}1.3%$ with high reliability and showing the gradually stability after 2010.

• Journal of Korean Society of Steel Construction
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• v.24 no.3
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• pp.289-299
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• 2012

The goal of this paper is to apply the multi-step Taylor method to a space truss, a non-linear discrete dynamic system, and analyze the non-linear dynamic response and unstable behavior of the structures. The accurate solution based on an analytical approach is needed to deal with the inverse problem, or the dynamic instability of a space truss, because the governing equation has geometrical non-linearity. Therefore, the governing motion equations of the space truss were formulated by considering non-linearity, where an accurate analytical solution could be obtained using the Taylor method. To verify the accuracy of the applied method, an SDOF model was adopted, and the analysis using the Taylor method was compared with the result of the 4th order Runge-Kutta method. Moreover, the dynamic instability and buckling characteristics of the adopted model under step excitation was investigated. The result of the comparison between the two methods of analysis was well matched, and the investigation shows that the dynamic response and the attractors in the phase space can also delineate dynamic snapping under step excitation, and damping affects the displacement of the truss. The analysis shows that dynamic buckling occurs at approximately 77% and 83% of the static buckling in the undamped and damped systems, respectively.

• Journal of the Korean earth science society
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• v.33 no.1
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• pp.32-38
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• 2012

Mean background concentrations of greenhouse gases such as $CO_2$ and $CH_4$ were estimated on Ulleungdo using PICARRO Cavity Ring-Down Spectroscopy (CRDS) analyzer. To improve the accuracy of $CO_2$ and $CH_4$ concentrations, a standardized QA${\cdot}$QC (Quality Assurance Quality Control) procedure was employed with three steps: 1) the inspection procedure of physical limitation (e.g. the exclusion of data corresponding to the number of data of ${\leq}$50%) for hourly mean values, 2) a stage inspection (e.g. the use of data corresponding to ${\geq}15$ observations per day) for daily mean values, and 3) a fast fourier transform (FFT) analysis using curve-fitting methods for the investigation of climatic characteristics. The monthly mean concentrations of $CO_2$ and $CH_4$ derived from three-step QA${\cdot}$QC procedure were then compared with those observed at Anmyundo (Korea) and Ryori (Japan). Overall, the error of mean $CO_2$ and $CH_4$ concentrations estimated in this study distinctly decreased. However, in comparison with their concentrations monitored at Ryori, the $CO_2$ concentration at estimated at Ulleungdo is soemwhat lower than that of Anmyundo due to the missing data, which is statistically significant. On the other hand, the former has a statistically significant higher value of $CH_4$ that of the latter.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.763-771
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• 2009

As the demand on long span structures increases more in recent years, the excessive deflection, in addition to the ultimate strength, in horizontal members becomes a very important issue. For this reason, as an alternative method to effectively solve the deflection problems, the application of post-tensioned structural system with unbonded tendon increases gradually. However, most of the existing researches on post-tensioned members with unbonded tendons (UPT) focused on the ultimate flexural strength, which would be impossible or improper to check serviceability such as deflections. Therefore, this study aims at proposing a stress prediction model for unbonded tendons that is applicable to the behavior of UPT members from the very initial loading stages, post-cracking states, and service to ultimate conditions. The applicability and accuracy of the proposed model were also evaluated comparing to the existing test results from literature. Based on such comparison results, it was verified that the proposed model provided very good predictions on tendon stresses of UPT members at various loading stages regardless their different characteristics; wide range of reinforcement index, different loading patterns, and etc. The proposed model especially well considered the effect of various loading types on stress increases of unbonded tendons, and it was also very suitable to apply on the over-reinforced members that easily happened during strengthening/repairing work.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.679-686
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• 2014

This study analysed differences between importance and performance of 2014 forest interpreter training program through IPA with the aim to provide suggestions and improvement. First the results of a comparison of the overall average of performance and importance showed importance is higher than performance. Afterwards, the result of IPA showed that confidence of being an interpreter, active involvement, the understanding of the value of forest, expansion of the understanding of forest, the understanding of the mission of interpreter, and the understanding of the qualification of interpreter, those 6 items belong to the I quadrant. In the case of the II quadrant there were interest of the content of education and to learn a lot of things through education. Next, those how to deal with service, planning interpreter programs, clarity of the content of education, accuracy of the content of education, validity of the content of education, appropriate number of participants, and appropriate time of education involved in III quadrant. Finally, concentration in the education and the understanding of the topic of education situated in IV quadrant.

• Journal of Korean Society of Forest Science
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• v.79 no.1
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• pp.1-15
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• 1990

In this study the stem analysis program, which can be operated with personal computer was developed to reduce time and cost of calculation, and to increase accuracy of analysis. The stem analysis method used in this program was compared with other methods. The results obtained were as follows : The value, 1/100mm measured from the latest annual ring measurement machine (Jahrringme${\beta}$geraete Johan Type II) was automatically inputed to the computer and saved into given file name. Turbo Pascal program was written to do this. The measured data was analyzed by stem analysis calculation program written by Fortran-77. Volume and height increments were approximated by spline function, and diameter of the stem disk was calculated by quadratic mean method. The increment values calculated by the programs were printed annually and in every five-year. Stem analysis diagram and several increment graphs were also easily printed. The result compared between those analysis methods showed that quadratic mean could reduce the error caused from eccentric pith. When the stem taper curve method, approximated by spline function, was used in the calculation of tree height and volume, increments would be more exactly calculated.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.419-426
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• 2005

This study is to propose a modified equivalent frame model for flat plate slabs under lateral loads. ACI 318 (2002) allows equivalent frame methods to conduct two-way slab system analysis subjected to gravity loads as well as lateral loads. Since the equivalent frame method in the ACI 318 (2002) has been developed base on the behavior of two-way system for gravity loads, and nay not predict the behavior of flat plate slabs under lateral loads with good precision. This study develops a modified equivalent frame model which can give more precise answer for flat plate slabs under lateral loads. This model reflects the actual force transfer mechanism among the components of flat plate slab system, which are slabs, columns and torsional members, more accurately under lateral loads than existing equivalent frame models. The accuracy of this model is verified by comparing the analysis results using the proposed model with the results of finite element analysis. The analysis results of other existing models are included in the comparison. For this purpose, 2 story building having 3 spans in both directions is considered. Analytical results show that the modified equivalent frame model produces comparable drift and slab internal moments with those obtained from finite element analysis.

• Journal of the Korea Convergence Society
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• v.8 no.5
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• pp.79-85
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• 2017

The purpose of this research was to evaluate the clinical and the instrument of convergence utility of transient elastography (FibroScan(R):electromagnetic wave) in diagnosing and treating liver ailments through a comparison and an analysis between liver function blood test and transient elastography (FibroScan(R)) in patients with chronic hepatitis B virus infection. Of all the patients with chronic hepatitis B virus infection who visited clinic B in Daejeon City between July 1, 2015, and February 28, 2016, 75 who underwent a FibroScan(R) test were selected for this study. Their laboratory and liver function test results were compared for a correlation analysis before constructing an ROC (Receiver Operation Characteristic) curve. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were 0.572 and 0.502, respectively, and showed highest correlation with fibrosis score, with statistical significance (p<0.000). Gamma glutamyltranspeptidase, total bilirubin, and alkaline phosphatase levels also showed relatively significant correlations in this order of sequence, while -fetoprotein and total protein levels did not show any statistically significant values. Albumin (-0.449) and platelet levels (-0.373) showed negative correlations with each other and no correlation with fibrosis score (p < 0.000). As liver fibrosis worsened, the accuracy of the ROC curve increased. At the F4 stage, which is the cirrhotic stage, the largest area under the curve was observed. FibroScan(R) showed significant correlation with the ALT (serum glutamic pyruvic transaminase) and AST (serum glutamic oxaloacetic transaminase) levels in the liver function test, which is a routine test for patients with chronic liver ailments. This implies that fibrosis correlates with liver inflammation severity.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.171-181
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• 2003

The nose fairings of KSR-III are designed to be separated from the rocket by explosive force at the mission altitude to expose the payload. Adequate amount of separation force should be imposed to allow safe separation without collision between the fairings and the rocket, and the separation device was designed for the separation at very high altitude where almost no air load was expected. As the development of KSR-III goes on, several design changes have made and lower separation altitude of 45km is expected as a result. Under these circumstances, it is required to determine if the nose fairings can be separated without collision with much severer air load than for the design condition. In this study, the 6-DOF motion analysis program, PASEM, which was developed to predict the strap-on booster separation, is modified to simulate the pivotal motion of the fairings at early stages of separation. The accuracy of pivot motion simulation is validated by comparison with the results of ground test and the accurate separation conditions are deduced from it. Trajectory simulations are performed to see if separation without collision is possible with varying angle of attack, direction of gravity, and the effect of gust. It is also found that reducing the separation angle of the clamshell hinge from 60 degrees to 40 degrees can enhance separation safety and separation at lower altitude of 40km can be done without collision.