• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.419-424
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• 2002

The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial criticality In February, 1995. Many experiments should be safely performed to activate the utilization of the HANARO. A flow simulation facility is being developed for the endurance test of reactivity control units for extended life times and the verification of structural integrity of those experimental facilities prior to loading in the HANARO. This test facility is composed of three major parts; a half-core structure assembly, flow circulation system and support system. The flow circulation system is composed of a circulation pump, a core flow pipe, a core bypass flow pipe and instruments. The system is to be filled with de-mineralized water and the flow should be met the design flow to simulate similar flow characteristics in the core channel of the half-core test facility to the HANARO. This paper, therefore, describes an analytical analysis to study the flow behavior of the system. The computational flow analysis has been performed for the verification of system pressure variation through the three-dimensional analysis program with standard k-$\epsilon$ turbulence model and for the verification of the structural piping integrity through the finite element method. The results of the analysis are satisfied the design requirements and structural piping integrity of flow circulation system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.3
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• pp.74-83
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• 2020

Securing excellent pilots is not only directly linked to the military's improved combat capabilities, but also a way to minimize human and property losses from aircraft accidents. Therefore, a scientific method is needed to diagnose pilot aptitude from the pilot selection process and select those with high accident potential, those who are dropped out of the flight training process, and those who are not suitable for pilot life in advance. Developed countries have implemented pilot aptitude tests to solve these problems early on, but so far, the Korean Army has not introduced a pilot aptitude test system that uses diagnostic tools in the helicopter pilot selection process. Therefore, in this study, scientific diagnostic tools are developed for selecting helicopter pilots, and through this, it is predicted that the number of people who are likely to be dropped out of the training course and who have the potential for accidents will be selected in advance and eliminated in the selection process. In this context, prior research examined the key factors involved in the pilot aptitude test. Through this, the aptitude test items were developed and aptitude tests were conducted on student pilots currently in flight training, and the results of flight training were analyzed.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.3
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• pp.288-297
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• 2012

This paper describes the verification test on Electromagnetic Environmental Effects(E3), which conducted on ground as a final step to confirm the normal operation of ELINT pod and Safety-of-Flight of KF-16C/D mounted with ELINT pod prior to the initial flight. Based on MIL-STD-464A, indispensable 7 requirements among 14 detailed requirements total were carried out in the test. Considering the Safety-of-Flight(SOF), we invest a great deal of time and effort on Hazards of Electromagnetic Radiation to Ordnance(HERO) and Intra-system EMC test. E3 test and evaluation were performed on 62 equipments of KF-16C/D, respectively. As a result, we verify that KF-16C/D mounted with ELINT pod(hereafter "system") are electromagnetically compatible among all subsystems and equipment within the system and with environments caused by electromagnetic effects external to the system.

• Journal of Korean Society for Quality Management
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• v.30 no.1
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• pp.74-96
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• 2002

The objectives of this study is to suggest the rectifying sampling inspection plan considering quality cost. Limiting quality level(LQL) plans(also called LTPD plans) and outgoing quality(OQ) plans are considered. The Hald's linear cost model is discussed with and without a beta prior for the distribution of the fraction of nonconforming items in a lot. It is assumed that the sampling inspection is error free. We consider the design of reliability acceptance sampling plan (RASP) for failure rate level qualification at selected confidence level. The lifetime distribution of products is assumed to be exponential. MIL-STD-690C and K C 6032 standards provide this procedures. But these procedures have some questions to apply in the field. The cost of test and confidence level(1-$\beta$ risk) are the problem between supplier and user. So, we suggest that the optimal life test sampling inspection plans using simple linear cost model considering product cost, capability of environment chamber, environmental test cost, and etc. Especially, we consider a reliability of lots that contain some nonconforming items. In this case we assumed that a nonconforming item fail after environmental life test. Finally, we develope the algorithm of the optimal sampling inspection plan based on minimum costs for rectifying inspection and RASP. And computer application programs are developed So, it is shown how the desired sampling plan can be easily found.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.1
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• pp.79-86
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• 2007

The Magnus effect measurement apparatus was designed and built for spinning wind tunnel model which would simulate the rotation of projectiles. Prior to the high speed test, the ground functional test and the low speed test were carried out in the Agency for Defense Development's Low Speed Wind Tunnel(ADD-LSWT) at spin rates from about 6,000 to 10,000 rpm. Magnus force and moment were measured on the spinning projectile model at velocity of 100 m/s. It was shown that the Magnus force and moment were linear function of spin parameter. The test results were compared with Magnus test run on the same configuration in the Arnold Engineering Development Center's Propulsion Tunnel 4T(AEDC-4T).

• Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.38-43
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• 2006

We developed and evaluated a method of short-term acute toxicity testing based on the feeding behavior of Ceriodaphnia dubia. In prior toxicity tests, neonates of C. dubia were hatched and cultivated with the addition of yeast only for the preparation of the transparent daphnid's gut. Scenedesmus subspicatus was supplied as food after 1 to 6 h of exposure to toxicants. The effects of 1-h and 6-h exposure time on test sensitivity did not significantly differ. A comparison of the short-term l-h acute toxicity test developed in this study to the standard 48-h acute toxicity test using heavy metals, cyanide, and pentachlorophenol indicated that the 1-h test provided an acceptable sensitivity level in toxicity testing of C. dubia..

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.2
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• pp.79-88
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• 2013

Steel plate concrete (SC) composite structure is now being recognized as a promising technology applicable to nuclear power plants as it is faster and suitable for modular construction. It is required to identify its dynamic characteristics prior to perform the seismic design of the SC structure. Particularly, the damping ratio of the structure is one of the critical design factors to control the dynamic response of structure. This paper compares the criteria for the damping ratios of each type of structures which are prescribed in the regulatory guide for the nuclear power plant. In order to identify the damping ratio of SC shear wall, this study made SC wall specimens and conducted experiments by cyclic lateral load tests and vibration tests with impact hammer. During the lateral loading test, SC wall specimens exhibited large ductile capacities with increasing amplitude of loading due to the confinement effects by the steel plate and the damping ratios increased until failure. The experimental results show that the damping ratios increased from about 6% to about 20% by increasing the load from the safe shutdown earthquake level to the ultimate strength level.

• Geosciences Journal
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• v.22 no.6
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• pp.1041-1052
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• 2018

A single-well push-drift-pull tracer test using two different tracers ($SF_6$ and salt) was performed at the Environmental Impact Test (EIT) site to determine suitable locations for monitoring wells and arrange them prior to artificial $CO_2$ injection and leak tests. Local-scale estimates of hydraulic properties (linear groundwater velocity and effective porosity) were obtained at the study site by the tracer test with two tracers. The mass recovery percentage of the volatile tracer ($SF_6$) was lower than that of the non-volatile tracer (salt) and increased drift time may make degassing of $SF_6$ intensified. The $CO_2$ leakage monitoring results for both unsaturated and saturated zones suggest that the $CO_2$ monitoring points should be located near points at which a high concentration gradient is expected. Based on the estimated hydraulic properties and tracer mass recovery rates, an optimal $CO_2$ monitoring network including boreholes for monitoring the unsaturated zone was constructed at the study site.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.4
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• pp.113-119
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• 2022

SU-Eohyeol pharmacopuncture(SUEP) was developed by adding Cervi Pantotrichum Cornu to Jungsongouhyul pharmacopuncture. This genotoxicity evaluation was performed to evaluate the mutagenic potential of the test substance SUEP agent using histidine, which requires strains of Salmonella typhimurium (TA98, TA100, TA1535, TA1537), and tryptophan, which requires Escherichia coli (WP2uvrA) strain in the presence and absence of metabolic activation. According to the results of the dose range finding study conducted prior to the main study, the dose levels of the test substance in the main study were determined as 100, 50, 25, 12.5, 6.25%, and positive and negative controls were established. As a result of the main study, the mean number of revertant colonies compared to negative controls was less than 2-fold at all dose levels of SUEP in all strains with and without metabolic activation. In the positive control group, the mean number of revertant colonies for each strain was markedly increased by more than two times compared to the negative control group. Based on the result of this study, the test substance, SUEP did not show any indication of mutagenic potential under the conditions of this study.

• International Journal of Advanced Culture Technology
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• v.11 no.3
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• pp.156-162
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• 2023

The purpose of this study was to examine the effects of peer scaffolding on the writing fluency of English language learners. This study was intended to confirm that peer scaffolding in English as a foreign language (EFL) writing classes can improve students' English proficiency. An analysis of 20 EFL learners studying at a university in Gyeonggi Province was conducted based on the English Proficiency Test. In this study, 20 intermediate learners with similar proficiency levels were included in the sample. Randomly, 10 students were designated as members of the control group, and 10 students were designated as members of the experimental group. In the experimental group, students practiced essay writing, while a skilled student provided scaffolding for a less skilled student. A variety of tools were used to gather data, including tests, questionnaires, and interviews Statistical analyses of quantitative data were conducted using t-tests for independent samples, whereas analyses of qualitative data were conducted based on themes. Pre-test results indicated a significant value of sig. =0.87, which was higher than α = 0.05. According to the results of this study, the writing performance of both experimental and control groups of students was equal and homogeneous prior to treatment. However, there were significant differences between the writing of students in the two groups after the completion of the program. Due to the post-test analysis of the writing test, the test resulted in a sig. =0 .043, a value lower than α = 0.05. As a result, the experimental group participants showed a marked improvement in their writing abilities after treatment.