• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.910-913
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• 2005

The pipe which it uses from the nuclear power plant or factory by a long period use and a corrosive action the inside defect occurs on the inside. abstract here. The ESPI method is in order to investigate the laser light in the measurement object it will be able to measure the wide territory whole in once, does not receive an effect in direction of defect not to be. has the strong point it will be able to measure a change of place arrowhead real-time defect. It measured a inside defect of pressure vessel by using ESPI and FEM. It compared a each method result.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
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• pp.484-489
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• 2008

We carried out a one-way heating experiment on the PC panel manufactured by changing the filling depths(20,30,40,50mm) of concrete regarding the fire strength in order to measure the inner concrete pressure which is a direct cause of concrete spalling. This fire experiment was conducted under the fire strength conditions of ISO 834 Standard, Modified Hydrocarbon and the maximum value of Pore Pressure was measured. As a result of analyzing the time it took to reach maximum pressure, it showed that the time rising to the maximum pressure of high strength concrete of 40MPa is slower than that of a 24MPa tunnel lining. In case of ISO fire conditions, spalling damage might take place in heating period of $20{\sim}40$ minutes in the range of $100{\sim}200^{\circ}C$ temperature. In case of MHC fire conditions, the area damaged by fire can appear after a lapse of $25{\sim}50$ minutes in the range of $150{\sim}250^{\circ}C$ temperature.

• 유공압시스템학회논문집
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• 제4권1호
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• pp.7-12
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• 2007

It is strongly requested to reduce fuel consumption because of high oil price and exhaust gases of road vehicles for environmental preservation. To solve these problems, several types of hybrid vehicles have been developed. Among them, flywheel hybrid vehicle using variable displacement pump/motor was already proposed as one of the feasible hybrid systems in place of hybrid vehicle by the conventional storage battery. The proposed flywheel hybrid vehicle is to keep constant pressure of high pressure line by the control of swash plate angle of flywheel pump/motor as pressure compensator. The efficiency of the overall system depends severely on the efficiency of hydraulic pump/motor in the energy saving hydraulic control system by simulation. According to the control methods of swash plate angle of piston pump/motor, there remain several problems to be solved. In this paper, experimental setup for energy saving is fabricated and the efficiency of energy saving is investigated by experiments with respect to various experimental conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1081-1086
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• 2007

It is strongly requested to reduce fuel consumption because of high oil price and exhaust gases of road vehicles for environmental preservation. To solve these problems, several types of hybrid vehicles have been developed. Among them, flywheel hybrid vehicle using variable displacement pump/motor was already proposed as one of the feasible hybrid systems in place of hybrid vehicle by the conventional storage battery. The proposed flywheel hybrid vehicle is to keep constant pressure of high pressure line by the control of swash plate angle of flywheel pump/motor as pressure compensator. The efficiency of the overall system depends severely on the efficiency of hydraulic pump/motor in the energy saving hydraulic control system by simulation. According to the control methods of swash plate angle of piston pump/motor, there remain several problems to be solved. In this paper, experimental setup for energy saving is fabricated and the efficiency of energy saving is investigated by experiments with respect to various experimental conditions.

• 한국안전학회지
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• 제19권4호
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• pp.14-19
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• 2004

Boiler is a hazardous equipment to have potential explosion ail the time. And not only it has malfunction at explosion. it lead to people death but also secondary accident such as explosion and fire. Therefore, this equipment should not be broken for keeping its own function. And also, high level of safety should be kept in the process of the use not to be malfunctioned. A large scale of accident due to boiler explosion can be preventive in advance. Boiler fracture is occurred by instant expansion (approximately 1700 time) from quick evaporation of rater in boiler, due to pressure decrease in boiler Emitting energy from it is tremendous and it is so dangerous because of its high temperature. Secondary explosion such as fire is also a main hazard occurring at fuel supply place. If any devices with high pressure is broken, then not only boiler vessel but also components of it are spread with high speed, causing secondary accident. This study is to analyze integrally accident cause of fire and flue tube boiler to have occurred pressure fracture actually, to show countermeasures to prevent accident loss from the fire and flue tube boiler.

• 한국정밀공학회지
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• 제24권5호
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• pp.68-76
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• 2007

It is strongly requested to reduce fuel consumption because of high oil price and exhaust gases of road vehicles for environmental preservation. To solve these problems, several types of hybrid vehicles have been developed. Among them, flywheel hybrid vehicle using variable displacement pump/motor was already proposed as one of the feasible hybrid systems in place of hybrid vehicle by the conventional storage battery. The proposed flywheel hybrid vehicle is to keep constant pressure of high pressure line by the control of swash plate angle of flywheel pump/motor as pressure compensator. The efficiency of the overall system depends severely on the efficiency of hydraulic pump/motor in the energy saving hydraulic control system by simulation. According to the control methods of swash plate angle of piston pump/motor, there remain several problems to be solved. In this paper, experimental setup for energy saving is fabricated and the efficiency of energy saving is investigated by experiments with respect to various experimental conditions.

• 한국재료학회지
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• 제21권11호
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• pp.623-627
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• 2011

This is a study on the distribution of acoustic emission parameters during a burst test for a type-II CNG vehicle fuel tank. A resonant AE sensor with a central frequency of 150 kHz was attached to the composite materials in the center of the fuel tank. The pressure was increased from 30 to 100% of the expected burst pressure and was maintained for 10 minutes at each level. Damage at 70% of expected burst pressure occurred by various damage mechanisms including fiber breakage and delamination, while that of below 60% only occurred by matrix crack initiation and growth. The count, duration and rise time of the AE signal at 60% of the expected burst pressure are distributed below 500, 5000 ${\mu}s$ and 300 ${\mu}s$, respectively. Then, at above 70% they increased with pressure by superimposing of individual AE signal generated at a nearby place. These results confirmed that the analysis of the distribution of AE parameters is an effective tool for estimating damage of a CNG fuel tank.

• 한국구조물진단유지관리공학회 논문집
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• 제19권3호
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• pp.130-138
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• 2015

본 연구에서는 고유동 고강도 콘크리트의 현장타설에의 적용성 검토를 위해 거푸집의 측압검토를 수행하였다. 이를 위해 타설높이 및 타설속도를 주요변수로 정하여 실험체를 제작한 후, 수행한 실험으로부터 측압 및 온도변화를 측정하였다. 고유동 고강도 콘크리트의 최대 측압은 굳지 않은 콘크리트의 측압으로 나타났으며, 타설 직후 측압이 감소하기 시작하여 12시간 이후 안정화를 보였다. 3~4시간 이후 안정화가 나타나는 보통 콘크리트와 측압이 감소하는 경향은 유사하다. 타설속도가 빠를수록 최대 측압이 크게 발생하였으며, 시간의 경과에 따른 감소량은 거의 유사하였다. 또한 수화열과 측압감소 사이에 직접적인 연관성은 나타나지 않았다.

• 한국가스학회지
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• 제16권4호
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• pp.59-64
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• 2012

LPG 저장설비에 부착된 압력방출밸브 방출관으로부터 분출된 가스의 확산에 대해 검토하였다. 통상 방출관은 안전한 장소인 수직 상방향으로 분출되도록 설치되어야 하며, 방출된 가스가 착화되더라도 저장탱크, 장치, 배관에 화염이 닿지 않도록 설치되어야 한다[1][2]. 그러나 우리나라에서는 방출구를 통한 분출방향에 대한 기준이 없이 다양한 방출구 형태가 존재한다. 따라서, 본 연구에서는 4가지 방출방향 즉 수직상방, 수직하방, 수평 2, 수직 4방향에 대해서 고려하였다. 방출구로부터 분출된 가스의 확산 시뮬레이션은 상용소프트웨어인 FLACS를 사용하였다. 이를 통해 수직하방, 수평 2, 수직 4방향으로 분출하도록 방출구를 설치하는 것은 지면에서의 착화를 방지하는 데 불리한 것으로 나타났다. 따라서 안전밸브로부터 분출된 가스를 방출구를 통해 안전하게 분출하기 위해서는 수직상방으로 분출되는 것이 최선임을 알 수 있었다.

• Korean Journal of Acupuncture
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• 제35권1호
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• pp.41-45
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• 2018

Objectives : To investigate minimum pressure by verifying changes in pressure due to bleeding amount during bloodletting-cupping therapy. Methods : (1) We compared adhesion performance of four different cupping cups of same size: two disposable cupping cups(A, B) and two reusable cupping cups(A, B) each were vacuumed three times and kept in place for 10 minutes. (2) We vacuumed two different sized disposable cupping cups(A), size.1(InnerDiameter 48.8 mm) and size.3(InnerDiameter 39.1 mm), twice each(-200 mmHg) on silicon plate. We injected water and air at regular intervals in cupping cups by using a syringe, and then measured change of pressure in cupping cups and pressure at the time of dropout. Results : (1) Pressure reduction was $4.75{\pm}2.78%$ on average in the order of 'Disposable[A]>reusable[B]>Disposable[B]>reusable[A]', so that pressure retention performance of disposable cups can't be regarded as inferior to that of reusable cups. (2) Pressure of disposable cupping B(size.1) decreased by an average of -40.08 mmHg per 5 ml of water. At -24.8 mmHg, when 22 ml of water has been injected, cup has come off. Pressure of disposable cupping B(size. 3) decreased by an average of -99.4 mmHg per 5 ml of water. At -48.6 mmHg, when 13 ml of water was injected, cupping came off. Conclusions : Considering reduction rate of pressure due to water injection, in case of bleeding more than 15 ml, size.3 cup always comes off, therefore it needs to be re-operated at least once. Meanwhile, size.1 cup does not always come off in the same condition, depending on the initial pressure and therefore, re-operation may be considered.