• International Journal of Naval Architecture and Ocean Engineering
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• 제4권1호
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• pp.20-32
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• 2012

A software system for a complex object scattering analysis, named SYSCOS, has been developed for a systematic radar cross section (RCS) analysis and reduction design. The system is based on the high frequency analysis methods of physical optics, geometrical optics, and physical theory of diffraction, which are suitable for RCS analysis of electromagnetically large and complex targets as like naval ships. In addition, a direct scattering center analysis function has been included, which gives relatively simple and intuitive way to discriminate problem areas in design stage when comparing with conventional image-based approaches. In this paper, the theoretical background and the organization of the SYSCOS system are presented. To verify its accuracy and to demonstrate its applicability, numerical analyses for a square plate, a sphere and a cylinder, a weapon system and a virtual naval ship have been carried out, of which results have been compared with analytic solutions and those obtained by the other existing software.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.2788-2802
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• 2021

Multigroup cross section (MG XS) generation by the UNIST in-house Monte Carlo (MC) code MCS for fast reactor analysis using nodal diffusion codes is reported. The feasibility of the approach is quantified for two sodium fast reactors (SFRs) specified in the OECD/NEA SFR benchmark: a 1000 MW_th metal-fueled SFR (MET-1000) and a 3600 MW_th oxide-fueled SFR (MOX-3600). The accuracy of a few-group XSs generated by MCS is verified using another MC code, Serpent 2. The neutronic steady-state whole-core problem is analyzed using MCS/RAST-K with a 24-group XS set. Various core parameters of interest (core k_eff, power profiles, and reactivity feedback coefficients) are obtained using both MCS/RAST-K and MCS. A code-to-code comparison indicates excellent agreement between the nodal diffusion solution and stochastic solution; the error in the core k_eff is less than 110 pcm, the root-mean-square error of the power profiles is within 1.0%, and the error of the reactivity feedback coefficients is within three standard deviations. Furthermore, using the super-homogenization-corrected XSs improves the prediction accuracy of the control rod worth and power profiles with all rods in. Therefore, the results demonstrate that employing the MCS MG XSs for the nodal diffusion code is feasible for high-fidelity analyses of fast reactors.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1789-1803
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• 2022

RAST-F is a new full-core analysis code based on the two-step approach that couples a multi-group cross-section generation Monte-Carlo code MCS and a multi-group nodal diffusion solver. To demonstrate the feasibility of using MCS/RAST-F for fast reactor analysis, this paper presents the coupled nodal code verification results for the MET-1000 and CAR-3600 benchmark cores. Three different multi-group cross-section calculation schemes are employed to improve the agreement between the nodal and reference solutions. The reference solution is obtained by the MCS code using continuous-energy nuclear data. Additionally, the MCS/RAST-F nodal solution is verified with results based on cross-section generated by collision probability code TULIP. A good agreement between MCS/RAST-F and reference solution is observed with less than 120 pcm discrepancy in k_eff and less than 1.2% root-mean-square error in power distribution. This study confirms the two-step approach MCS/RAST-F as a reliable tool for the three-dimensional simulation of reactor cores with fast spectrum.

• Structural Engineering and Mechanics
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• 제85권4호
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• pp.563-571
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• 2023

Girdling underpinning joints are key areas of concern for the pier-cutting bridge-lifting process. In this study, five specimens of an underpinning joint were prepared by varying the cross-sectional shape of the respective column, the process used to treat the beam-column interface (BCI), and the casting process. These specimens were subsequently analyzed through static failure tests. The BCI was found to be the weakest area of the joint, and the specimens containing a BCI underwent punching shear failure. The top of the girdling beam (GB) was subjected to a circumferential tensile force during slippage failure. Compared to the specimens with a smooth BCI, the specimens subjected to chiseling exhibited more pronounced circumferential compression at the BCI, which in turn considerably increased the shear capacity of the BCI and the ductility of the structure. The GB for the specimens containing a column with a circular cross-section exhibited better shear mechanical properties than the GB of other specimens. The BCI in specimens containing a column with a circular cross-section was more ductile during failure than that in specimens containing a column with a square cross-section.

• 간호행정학회지
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• 제6권2호
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• pp.211-225
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• 2000

With the drastically changing healthcare market, the adoption of DRG system and the use of Critical Pathway will be increased gradually in order to care hospitalized patients qualitatively and manage cost-effectively in Korea. The purpose of this quasi-experimental research is to apply and analyze the developed critical pathway to the patients with Cesarean section. 35 eligible subjects for the control group were chosen from postpartum patients who has delivered at H-hospital in Kwang-ju, and were questioned after appling previous care plan from May to December, 1998. For the experimental group, 37 subjects were chosen and questioned after applying Critical Pathway service from January to June, 1999. The instruments are a critical pathway for the patients with Cesarean section developed by chung(1998) and a questionnaire that evaluate patients and family members' satisfaction level. Also, educational materials were used to inform them in the process of Critical Pathway application. As a result of chi-square test on general characteristics, there is significant difference between control group and experimental group only in terms of room size(p= .010). There are no significant differences in the average length of stay in the hospital between control group and experimental group(t=.078). Also, the average medical consult fee has no difference significantly between two groups(t= .105). The findings showed that the experimental group with critical pathway service scored significantly higher than control group on the satisfaction level toward care services(p=.000). The items are post-operative care, postpartum exercise technique, breast feeding and breast manage through educational materials. In conclusion, the research indicates that the application of planned Critical Pathway can have a positive impact on satisfaction level of inpatients with Cesarian section.

• Asian-Australasian Journal of Animal Sciences
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• 제16권3호
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• pp.374-379
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• 2003

Four rumen fistulated Murrah buffaloes were used to study the effect of four diets differing in roughage to concentrate ratio on rumen biochemical changes, microbial enzyme profile and in sacco degradability of feed in a $4{\times}4$ Latin Square design. The animals were fed four diets consisting of 80:20, 70:30, 60:40 and 50:50 ratios of wheat straw and concentrate mixtures, respectively. Wheat straw and concentrate mixture were mixed with water (0.6 l/kg feed) and complete feed mixture was offered to the animals at 8:00 h and 16:00 h in two equal parts. The variation in pH of rumen liquor (difference of maximum and minimum during 0-8 h post feeding) increased with increasing level of concentrate mixture in the diet. There was no effect of diet composition on volatile fatty acids, total nitrogen and trichloro-acetic acid precipitable nitrogen in the rumen liquor, but ammonia nitrogen increased with increasing level of concentrate mixture in the ration. Major portions of all fibre degrading enzymes were present in the particulate material (PM) of the rumen contents, but protease was absent in PM fraction. The activities of micro-crystalline cellulase, acetyl esterase and protease increased with increase in the level of concentrate mixture, but the activities of other enzymes (carboxymethylcellulase, filter paper degrading activity, xylanase, $\beta$-glucosidase and $\beta$-xylosidase) were not affected. The in sacco degradability and effective degradability of feeds increased with increasing level of concentrate mixture in the ration.

• 한국구조물진단유지관리공학회 논문집
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• 제23권1호
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• pp.36-44
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• 2019

본 연구의 목적은 강 - PC 복합모듈 골조를 구성하는 프레스 성형된 비대칭 기둥과 보 접합부의 구조적 성능을 평가하는 것이다. 모듈러 골조를 구성하는 대부분의 접합부는 폐쇄형의 사각형 강재 기둥 단면을 주로 사용한다. 폐쇄형의 기둥 단면을 사용한 기둥-보 접합부는 시공성을 감소시키고 내화성을 확보하는데 어려움이 있다. 이러한 단점을 극복하기 위하여 강판을 프레스로 성형하여 비대칭 개방형 단면 내에 콘크리트를 충진하는 것이다. 프레스 성형된 비대칭 기둥-보 접합부의 구조적 성능을 조사하기 위해 총 4개의 실험체를 제작하였다. 실험결과, 비대칭 기둥의 구조적 성능과 거동이 비대칭 기둥 단면이 합성되는지 또는 기둥의 폭-두께 비율에 따라 달라지는지를 보여주었다. 프레스 성형된 비대칭 기둥-보 접합부의 구조적 성능은 실험결과와 이론식을 비교하여 평가하였다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1996년도 학술발표회
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• pp.68-71
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• 1996

The thermal response of sprinkler is characterized by the response time index(RTI). The RTI represents the product of the thermal time constant for the heat responsive element of a sprinkler and the square root of the hot air velocity at plunge test. A plunge test is adapted for measuring RTI, wherein a sprinkler is suddenly immersed in the steady flow in the test section of a hot air tunnel. The method of measurements of the response parameters is presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.93-100
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• 2000

In this study, we used photoelastic coating method which is a kind of model test for examining the stress condition of rock masses around underground structures. Using this method, we could know adaptability and usefulness of photoelastic coating method for various shape of tunnel models. And, in spite of higher cross section efficiency, square shape model showed unstable status because of high stress concentration. So, we cut the slits at the each corner of tunnel, and we could make more stable stress condition by means of moving high stress concentration to rock mass.

• 한국안전학회지
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• 제7권4호
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• pp.85-94
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• 1992

This paper, discribes analysis of theree - dimensional extrusion with the use of dual stream functions, By this method admissible velocity fields for the extrusion of three- dimensional flow was newly derived kinematically. For square section the extrusion pressure was calculated by numerical solution program which was based on the upper bound analysis. The relationship between relative extrusion pressure and reduction of area, relative die length and constant friction factors were successfully calculated which was newly developed in this study. The results could be applied to design extrusion die.