• Title/Summary/Keyword: Pressure-tightness

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Corrosion and Sliding Properties of the Nickel-Based Alloys for the Valve Seats Application

  • Honda, Tadashi
    • Corrosion Science and Technology
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    • v.7 no.2
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    • pp.92-98
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    • 2008
  • This paper describes the experiments of the corrosion and the sliding tests of the nickel-based alloys for the gate valve seating materials used at high pressure and temperature. The general corrosion rates and IGC susceptibility are tested in pressurized water at 533 K and 575 K and in Strauss test solution. The sliding tests have been done in pressurized water at 293 k, 473 K and 573 k. The alloys containing above 10% chromium may have the anti-corrosion properties that could be applied to the valve seats for the power plants. The good sliding performance and the good pressure tightness are obtained when the disc specimens that have hardness 500 to 600 Hv combined with the seat specimens that have hardness 250 to 410 Hv containing about 40 percent of iron. The large size gate valves sliding tests have certified the test results. The anti-wear properties of the seat alloy and the anti-IGC susceptibility of the disc alloy could be improved by the addition of silicon and niobium, respectively.

Development of cryogenic liquid-vapor separator and liquid-level meter operating under high pressure condition (고압 상황에서 작동되는 극저온 기액 분리기와 액체 계면 측정기의 개발)

  • Lee, Cheon-Kyu;Hwang, Gyu-Wan;Jeong, Sang-Kwon
    • Progress in Superconductivity and Cryogenics
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    • v.13 no.1
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    • pp.51-55
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    • 2011
  • In this study, the liquid-vapor (L-V) separator equipped with liquid-level meter is developed. In the developed L-V separator, the flange is designed to be attachable so that the separator can be flexibly applied under any cases where the volumetric of L-V separator is varied by the system requirement. The leak-tightness between the attachable flange and the chamber is experimentally confirmed with the use of double groove indium wire sealing even under the high pressure up to 20 bar. In addition, the liquid-level meter is designed and fabricated to figure out the inner state of L-V separator. It consists with 19 carbon composition resistors in series. All resistors are separately calibrated in the temperature range from 77 K to 200 K. The performance of the L-V separator and the liquid-level meter is investigated with experimental tests, and the result is presented in this paper.

A Study on Establishment of Brassiere Size and Clothing Pressure for the Twenties-aged Women (20대 여성의 브래지어 치수설정과 의복압에 관한 연구)

  • 박유신;임영자
    • Journal of the Korean Society of Costume
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    • v.52 no.8
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    • pp.15-27
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    • 2002
  • To set the measurements of bras for women in their 20s, considering the comfortableness in wearing and tightness, this paper conducted a questionnaire survey concerning breasts and bras as well as measurements of body and contact surface pressure. Easier and more accurate method of determining cup sizes based on the breast circumference is recommended to make up for the problem of current bra size system that can falsely measure cup sizes. Lower chest circumference was set at 5 cm equal intervals, and the breast circumference applicable to the cup size was set starting from the standard, 18 cm (A-cup), at 2 cm equal intervals, which gave the best coverage (88.1%).

The Study of passenger Car Design of korean High Speed Train (한국형 고속전철 객차 개발 연구)

  • 박만수;박광복;임성근
    • Proceedings of the KSR Conference
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    • 2000.05a
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    • pp.563-575
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    • 2000
  • This study was carried out about the system engineering, the design, and Mock-up for the development of passenger car of Korean High Speed Train of maximum operating speed of 350km/h. The design was studied to carbody section & lay out, ring, fitting, carbody, electrical system based on Korean-TGV. The design of aluminium alloy carbody which was enabled to reduce the weight of carbody structure and was studied with construction of air-tightness. Air pressure controlled system provided to comfort passenger due to a reduction of difference pressure between inside and outside of passenger room on running of the tunnel. The Interior design was performed in order to satisfy high speed and comfort to study by the modern design. The electrical system was designed two parts of logic and network for high reliability of train.

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Probabilistic Study on Pressure Behavior in Concrete Vacuum Tube Structures (콘크리트 진공튜브의 압력 변화에 대한 확률적 평가)

  • Park, Joonam
    • Journal of the Korean Society for Railway
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    • v.17 no.3
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    • pp.186-192
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    • 2014
  • In this paper, a reliability analysis is performed where the pressure change inside a concrete tube is probabilistically estimated considering the uncertainties inherent in the material and the system discontinuity. A set of uncertain quantities related to the equivalent system air permeability and the atmospheric pressure, are defined as random variables with specific distribution. The pressure change inside a concrete tube is then probabilistically described using both analytical and simulation approaches. The reliability analysis confirms that the geometric configuration of a concrete tube needs to be changed from the initial configuration obtained from the deterministic analysis.

The Effect of the Skinny Pants on the Physiological Responses and Subjective Pressure (스키니 진 착용이 인체생리반응과 주관적 압박감에 미치는 영향)

  • Kweon, Soo-Ae
    • Korean Journal of Human Ecology
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    • v.21 no.3
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    • pp.567-576
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    • 2012
  • The purpose of this study was to analyze and determine the relationship between physiological responses including blood flow rate and garment pressure, and the feeling of restrictive tightness associated with the wearing skinny pants as a popular clothing style. Evaluation was based on material type, posture and activity type, and body part location. Five female college students took part in this research. Five kinds of experimental clothes with waist measurements of 66cm were chosen. An analysis of the selected skinny pants demonstrated the degree of the whole looseness was higher in this order: clothing type A>B>D>C, and E with E being knitted cloth. Garment pressure was the highest in the front knee portions and was lowest in the outside thigh region. Garment pressure was highest in this sequence : clothing type C>=D>A>=B>E. In terms of posture and activity types, garment pressure was the highest when research participants were crouching, and was the lowest when standing. The blood flow rate was highest in this order: clothing type E>D>B>A>C. Type C skinny pants impeded blood flow and demonstrated the tightest and most restrictive relationship. Blood flow rate varied depending on the type of movement and was highest in this order: getting up, rowing, kicking, jumping and O-shaped leg posture. The results of subjective pressure evaluation demonstrated that pressure was highest in this order: E>=C>B>A>D. These results suggests the need to improve on the patterns and the material design in the area of the front knees. The degree of the looseness when wearing skinny pants did not always correspond to garment pressure or subjective sensation.

Oswestry Disability Analysis of Fuzzy Control Multi-cup Electric Cupping System

  • Kim, Jong-Chan;Ko, Jae-Sub;Wei, Tung-Shuen;Kim, Chee-Yong;Choi, Heung-Kook
    • Journal of Korea Multimedia Society
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    • v.18 no.2
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    • pp.207-217
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    • 2015
  • A multi-cup electric cupping system (MECS) was proposed, based on the ancient cupping method. MECS consisted of several cups that could be used simultaneously to treat 85 lumbago patients. Each cup was equipped with its own pump and pressure-monitoring system. The vacuum pressure of the cups was controlled using fuzzy logic. Through automated control of the vacuum pressure, long-term relief of muscle tightness was achieved. To develop a scientific foundation for this alternative treatment, we compared the Oswestry Disability Index (ODI) scores from conventional basic cupping to the ODI scores for our proposed MECS. The ODI scores using MECS decreased from $11.71{\pm}1.61$ before treatment to $4.81{\pm}1.48$ and $1.87{\pm}1.61$ after three and five treatments, respectively. The improvement rate in the ODI scores using MECS after three treatments was higher than that achieved by basic cupping. These results, combined with the convenience offered by enhanced information technology and fuzzy logic capabilities, should increase the efficiency of this device, and facilitate the opportunity to further explore the potential of Oriental medical practices.

Research of Novel Water Cooling Jacket for Explosion-proof Motor

  • Wang, Yu;He, Huiming;Bai, Baodong
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.1
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    • pp.67-71
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    • 2014
  • The well tightness of the coal mining water-cooling explosion-proof motor results in difficult heat dissipation, high hydraulic pressure is needed to increase the cooling effect. However, high hydraulic pressure may lead motor shell to deform, which makes it difficult to change the motor and maintain the motor unit. The method of adding keyhole caulk weld spots on the outer cooling water jacket was proposed to solve the problem. Based on the elasticity mechanics equations and the principle of finite element method the stresses and the deformations of the traditional and novel outer cooling water jacket were calculated separately. A hydraulic pressure experiment of the both cooling water jackets was constructed. Obviously, the stress and the deformation of the novel cooling water jacket are lower. The experimental result is consistent with the simulation results. It is effective to reduce the stress and the deformation of the cooling water jacket by adding the keyhole caulk weld spots.

A Study on the Effects of Smoking Habit to Health Status in Some Male Employees (일부 남성 직장인에서 관찰된 흡연행태가 건강상태에 미치는 성향연구)

  • 한영미;이시백
    • Korean Journal of Health Education and Promotion
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    • v.7 no.1
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    • pp.54-63
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    • 1990
  • This study aims to find out the prevalence of smoking, and to analyze the effect of smoking for health status, and then to emphasize the necessity of stop smoking. The data used in this study are obtained from periodic health care programe at Health Care Center in a suburban hospital, and selected 435 males who have occupation. The independent varibles chosen for the analysis are general charactersitic variables and smoking habit. The dependent variables are designed to cover the health status of individual cases, and include blood pressure, blood cholesterol level with HDL-cholesterol and blood triglyceride level, recent symptoms and recently being managed diseases. The result of this study are summarized as follows. 1) Percentage of smoker by the age groups is highest in 4th decade, being 71.1%. The second and third ranks are 6th and 7th decades, being 53.5% and 44.4%, respectively. 2) In the view of socio-economic levels, smoking rate is higher in the groups who live at rural area and whoes occupation is labor or merchant. Smoking rate is significantly higher in the heavy drinking group. 3) Among the atherosclerotic risk factors, which include hypertension, HDL-cholesterol by total cholesterol ratio lower than 0.2 and triglyceride level higher than 200gm/dl, hypertension was not statistically associated with smoking, but others revealed statistically high association with smoking. 4) The groups who have the symptoms of severe fatigue, gastrointestinal symptoms, pulmonary symptoms, palpitation and chest tightness havepositive association with smoking. 5) The groups who have hypertension with cardiovascular diseases and gastrointestinal diseases showed highly significant association with non-smoking. 6) In relation of the smoking habit to the atherosclerotic risk factor index, smokers have more atherosclerotic risk factors, but that is not statistically significant. 7) In relation of the smoking habit to the recent symptom index, smokers have more symptoms than non-smokers with statistical significance. In conclusion, smokers have worse health status than non-smokers especially in the atherosclerotic risk factors such as hypertension or abnormal blood lipid status and have more symptoms such as severe fatigue, gastrointestinal symptoms, pulmonary symptoms, palpitation and chest tightness. And the campaingn against smoking should direct for the male in 4th decade because they have highest smoking rate.

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Flexible and Lined Segment Tunnel for Underground Compressed Air Energy Storage(CAES) (복공식 압축공기 지하저장을 위한 가변성 분할 라이닝 터널기술)

  • Kim, Hyung-Mok;Rryu, Dong-Woo;Chung, So-Keul;Song, Won-Kyong
    • Tunnel and Underground Space
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    • v.19 no.2
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    • pp.77-85
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    • 2009
  • Flexible and lined segment air-tight tunnelling technology for Compressed Air Energy Storage-Gas Turbine(CAES-G/T) power generation was introduced. The distinguished characteristics of the air-tight tunnel system can be summarized by two facts. One is that the high inner pressure due to compressed air is sustained by surrounding rock mass with allowing sufficient displacement of lining segment. The other is that the air-tightness of storage tunnel was enhanced by adopting a specially designed rubber sheet. The flexible lined air-tight underground tunnel can be constructed at a comparatively shallow depth and near urban area so that the locally distributed CAES-G/T power generation can be accomplished. In addition, this air-tight tunnelling technology can be applied to a variety of energy underground storage tunnels such as Compressed Natural Gas(CNG), Liquifed Petroleum Gas(LPG), DeMethyl Ether(DME) etc.