• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.719-722
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• 2002

The Displacement current measurement system used in this experiment because detecting the dynamic behavior of monolayers at the air-water interface is possible. It basically consists of a film balance, a pair of electrodes connected to each other through a sensitive ammeter. Here, one electrode is suspended in air and the other electrode is placed in the water. PBLG phase transformation measured by Maxwell-displacement-current-measurement method in surface of the water. Measured (surface pressure, displacement current and dipole moment) of monolayers of PBLG on the water surface. We measured displacement current that occur when changed temperature. Could know that displacement current is proportional in increase of temperature and great as experiment result.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1672-1675
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• 2003

In this study, we developed full automation test system for pressure vessel. This pressure vessel containing oxygen, nitrogen and carbon is widely used in industrial field. The test items of pressure vessel are divided into three branches which is weight measurement, water-hydraulic, and leakage test. After leakage test is completed, cleaning and dry progress is carried out. And control system is consist of three controller which is PLC, monitoring system and database system. PLC is control all of system. Monitoring system measures weight, pressure, flow etc and display to all conditions. Database system stores tested data. we design system to control all test modules in communication by a second period with three control modules. Finally, we verified this system by field test.

• International Journal of Precision Engineering and Manufacturing
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• 제5권1호
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• pp.55-59
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• 2004

This study developed a fully automated test system for pressure vessels, containing such as oxygen, nitrogen, which is widely used in many industries. The pressure vessel test has three major parts including weight measurement test, water-hydraulic test and leakage test followed by cleaning and drying. The control system for these tests consists of three parts: a PLC, a monitoring system and a database management system. The PLC oversees overall control of test machines, while the monitoring system measures and displays weight, pressure, flow etc. for every situations, and the database management system stores test data. These three modules are designed to communicate with one another at 1 Hz frequency alerting problematic situations to the operator. The system has gone through actual field tests for verification of performances.

• 한국소음진동공학회논문집
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• 제19권8호
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• pp.843-849
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• 2009

The reliable operation of a swing check valve in the main feed water system of a power plant is most essential for successful shout-down process. A failure to close the valve at proper time often leads to the instability of the main feed water system, or even to an emergency stop of the power plant. In reality it is a very difficult task to monitor the behavior of a swing check valve. Furthermore it is impossible to see the motion of the valve. In this work two measurements were carried out simultaneously to determine the precise valve closure time. The dynamic pressure measurements were made at the inlet and outlet regions of the swing check valve. The transient vibration of the valve housing in the direction of water flow was also measured, which enabled the measurement of the transient vibration of the valve housing near valve closure. By comparing the results produced from these measurements the precise valve closure time could be determined. By carrying out order tracking technique using the dynamic pressure signals and pump rpm signal, the complicated dynamic problems inside the main feed water system can be more easily dealt with. This measurement scheme might be implemented in a power plant on a real-time basis without much difficulty. If this could be implemented, valuable information essential for shut-down operations can readily be passed on to the main control room. The feasibility of this implementation was demonstrated by this experimental work.

• 한국융합학회논문지
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• 제10권1호
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• pp.149-154
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• 2019

밸브를 생산하는 공장에서 사용하는 기존의 밸브시험기는 압력을 수동 조작함으로서 정밀압력을 측정 할 수 없었다. 이를 개선하기 위하여 기존의 밸브시험기에 대하여 CATIA를 활용하여 설계하고 3차원 유한요소 해석코드인 ANSYS를 활용하여 설계된 밸브시험기에 대하여 거동해석을 수행하고 고압의 내부압력에 따른 내부누수, 총변형량, 변형률, 응력 등을 구하였다. 이러한 해석결과는 새로운 고압용 밸브시험기를 개발하기 위한 초기자료로 활용되었다.

• 한국압력기기공학회 논문집
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• 제7권1호
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• pp.9-16
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• 2011

Primary water stress corrosion cracking (PWSCC) has been found in the weld region of the nuclear power plant. Welding can produce tensile residual stress. Tensile residual stress contributes to the initiation and growth of PWSCC. It is important to estimate weld residual stress accurately to predict or prevent the initiation and growth of PWSCC. This paper shows the results of finite element analysis and measurement experiment for weld residual stress. For the study, four kinds of specimen were fabricated with the materials used in the nuclear power plant. Residual stresses were measured by four kinds of methods of hole drilling, x-ray diffraction, instrumented indentation and sectioning. Through the study, numerical analysis and measurement results were compared and the characteristics of each measurement technique were observed.

• 상하수도학회지
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• 제36권4호
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• pp.219-228
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• 2022

In this study, we propose a flow velocity evaluation scheme based on pressure measurement in pressurized pipeline systems. Conservation of mass and momentum equations can be decomposed into mean and perturbation of pressure head and flowrate, which provide the pressure head and flowrate relationship between upstream and donwstream point in pressurized pipeline system. The inverse impedance formulations were derived to address measured pressure at downstream to evaluation of flow velocity or pressure at any point of system. The convolution of response function to pressure head in downstream valve provides the flow velocity response in any point of the simple pipeline system. Simulation comparison between traditional method of characteristics and the proposed method provide good agreements between two distinct approaches.

• 상하수도학회지
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• 제19권1호
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• pp.8-15
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• 2005

Field measurement data on water leakage are not readily available and it causes inaccurate assessment of water demand and poor supply planning. In this study, the procedure for leakage detection and unaccounted water calculation is proposed and applied to a city. The city has suffered from the significant amount of leak water and the financial loss as a result. Measurements were made for pressure and flow at 18 locations before and after the repair. Repair of the leakage increased pressure up to $2.0kgf/cm^2$ and saved 17.1% of water supply from distribution reservoirs. Monetary value of annual water savings for the entire city amounts to 1 billion won. It is believed that leakage detection and data analysis conducted in this study will contribute to the change of current practice and to the establishment of better water supply management system.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4481-4490
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• 2022

In this study, a new rupture disk corrosion test (RDCT) method was developed for real-time detection of stress corrosion cracking (SCC) initiation of Alloy 600 in a primary water environment of pressurized water reactors. In the RDCT method, one side of a disk specimen was exposed to a simulated primary water at high temperature and pressure while the other side was maintained at ambient pressure, inducing a dome-shaped deformation and tensile stress on the specimen. When SCC occurs in the primary water environment, it leads to the specimen rupture or water leakage through the specimen, which can be detected in real-time using a pressure gauge. The tensile stress applied to the disk specimen was calculated using a finite element analysis. The tensile stress was calculated to increase as the specimen thickness decreased. The SCC initiation time of the specimen was evaluated by the RDCT method, from which result it was found that the crack initiation time decreased with the decrease of specimen thickness owing to the increase of applied stress. After the SCC initiation test, many cracks were observed on the specimen surface in an intergranular fracture mode, which is a typical characteristic of SCC in the primary water environment.

• 한국지구과학회지
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• 제28권7호
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• pp.838-846
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• 2007

미고결, 난투수층 퇴적층 시료의 투수계수와 전기비저항의 측정이 가능한 삼축압력 측정장치를 설계하고 제작하였다. 이 측정장치는 측정셀 전후에 입출력 유량측정시스템이 설치되어 시료의 봉압을 증가시키면서 투수계수와 전기비저항을 동시에 측정할 수 있다. 아치의 법칙과 실험전후의 시료 질량 변화와 부피를 이용하여 공극률을 측정할 수 있다. 실험을 위한 시료는 표준모래와 일라이트 진흙을 성분비율을 다양하게 혼합한 인공시료와 동해 울릉분지에서 채취한 현장시료를 사용하였다. 이들 시료들에 대한 투수계수, 전기비저항을 봉압이 증가함에 따라 측정하고 분석하였다. 봉합이 증가함에 따라서 투수계수와 공극률은 지수적으로 감소하고 전기비저항은 지수적으로 증가한다.