• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.281-288
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• 2011

Hydraulic hose assemblies deliver a fluid power in various oil pressure equipments such as construction machinery, automobile, aircraft, industrial machinery, machine tools, and machinery for ships, or they are used as pipes in oil pressure circuit. However, as the traditional measure for estimating life under the influence of various external factors incurs hardship in terms of time and expenses, it is essential to take accelerated life test by choosing the factor that suits the usage condition of the test object. The objective of the this study is to propose a acceleration model that takes both temperature and pressure without flexing condition into consideration. The life that is calculated by the equation for evaluating life and the test data show similar slopes as a result of comparing and analyzing the equation for evaluating life that is obtained in this research and the test data, which illustrates that they estimate life similarly, and the proposed equation is proved to be an accelerated life equation that presents the test results.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.2
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• pp.21-31
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• 2020

Environmental pollution and climate change in Vietnam are now becoming a major concern. This situation is increasing the pressure on the companies to improve their social responsibility in production and business activities and disclose the environmental information to meet the requirements of stakeholders. This study investigates the internal and external factors of the company that affects the environmental information disclosure of listed companies on the Vietnam stock market as business sector, firm size, corporate manager perceptions, profitability, financial leverage, community pressure, pressures from stakeholders, government pressure influencing environmental information disclosure. Analytical data collected through the survey of 120 listed companies on the Ho Chi Minh City Stock Exchange (HOSE). By testing Cronbach's Alpha, exploratory factor analysis (EFA) and logistic regression analysis, the results of the study show that the level of environmental information disclosure of listed companies on the stock market in Vietnam depends heavily on government regulations, followed by the pressure from stakeholders, community pressure, views of business managers, companies size, business sector, and particularly profitability and financial leverage factors that have a negative relationship with environmental information disclosure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.101-102
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• 2006

The purpose of this paper is pulsation-analysis of the swash plate type axial piston pump for excavator and the method of side branch hose application, which is used normally in construction equipments. In this paper, draw the mathematical modeling for pressure pulsation mechanism of the swash plate type axial piston pump for excavator, expression the flow pulsation in the pipelines by transfer matrix method, programmed simulation for pulsation by AMEsim software, and the reliability of that was verified by the comparison with the experimental results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.279-288
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• 2003

This study is the development of method on repairing concrete structure for progressing the durability of reinforced concrete. This method is wet spray method which compress and conduct mortar pre-mixed with polymer powder to hose by high pressure pump and spray it on the section of concrete structure through nozzle made specially. Characters of this method are that materials are selected with the sort of structure and the cause of deterioration and macro pores are removed in repaired section by conducting with high pressure and spraying with high velocity for progressing the durability of concrete structure. This study has carried out that the minimum capacity of rebound was measured with various condition and physical properties of sample made by spray method were estimated in comparing with sample made by previous hand method. Also, properties of long-term have carried out after this method was applied on site. According to experimental study, the capacity of rebound showed below 5% and physical properties of sample made by spray method were superior to that of sample made by hand method and physical and durable properties of long-term showed excellence.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.947-952
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• 2010

Components such as pressure vessel, hydraulic hose assembly, accumulator, hydraulic cylinder, hydraulic valve, pipe, etc., are tested under the impulse-pressure conditions prescribed in ISO and SAE standards. The impulse pressure test machine needs to have a high pressure, a precise control system and a long life. It should satisfy the requirements for fabrication of the impulse tester to generate ultra high pressure in the hydraulic system. In the impulse tester, a servo-valve control system is adopted; although the control application is convenient, it is expensive owing to the cost of developing the system. The type of the control system determines the pressure wave, which affects the components that are tested. In this study, the manufacturing process and the intensifier system design related to the flow, pressure, and the increasing rate of pressure are investigated. The results indicate the ultra high pressure waves in the system.

• Journal of the Korean Institute of Gas
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• v.17 no.3
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• pp.8-13
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• 2013

The purpose of this paper is to study for fire example by fuel leakage in LPG Vehicle. At first example, the car was repaired the fuel line that was connected with pressure hose between fuel regulator and injector in engine. But the service man was not very tighten with regular torque. At a result, the gas leaked on hot parts of engine. It verified the production of fire by engine heat. At second example, when the repair man, after replacement the injector, inserted the injector in a assembling part of it, he didn't the transform condition of fixing part. Therefore, the tearing phenomenon of O ring producted the controlled leakage of fuel by the injector deflection. It found the fact that the fuel leaked with gap of O ring. At third example. the fuel-cut solenoid valve was lined with pressure regulator unit. But the service man didn't throughly certify the leaked work of connected parts after repaired it. As a result, it certified the fire by engine heating leaked liquefied petroleum gas. Therefore it have to minimize the fire production that the driver should do no problem to throughly manage the fuel system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5C
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• pp.303-311
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• 2008

In the case of bi-directional high pressure pile load test with double-acting jack, the shortcomings of bi-directional pile load test with single-acting jack could be solved, low-cost of test could be sure, the limits of loading capacity could be overcome and quality assurance of service plie could be confirmed. In this study, to confirm the stability, the reliability and the application of bi-directional high pressure pile load test with double-acting jack, the calibration test for high pressure oil jacks, the length of high pressure hose and tunable high pressure pipe system were performed. As a result, credibility was very high because the reliability of test results was approached at about 1.0.

• Fibers and Polymers
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• v.7 no.4
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• pp.389-397
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• 2006

The beneficial effects of graduated compression stockings (GCS) in prophylaxis and treatment of venous disorders of human lower extremity have been recognized. However, their pressure functional performances are variable and unstable in practical applications, and the exact mechanisms of action remain controversial. Direct surface pressure measurements and indirect material properties testing are not enough for fully understanding the interaction between stocking and leg. A three dimensional (3D) biomechanical mathematical model for numerically simulating the interaction between leg and GCS in dynamic wear was developed based on the actual geometry of the female leg obtained from 3D reconstruction of MR images and the real size and mechanical properties of the compression stocking prototype. The biomechanical solid leg model consists of bones and soft tissues, and an orthotropic shell model is built for the stocking hose. The dynamic putting-on process is simulated by defining the contact of finite relative sliding between the two objects. The surface pressure magnitude and distribution along the different height levels of the leg and stress profiles of stockings were simulated. As well, their dynamic alterations with time processing were quantitatively analyzed. Through validation, the simulated results showed a reasonable agreement with the experimental measurements, and the simulated pressure gradient distribution from the ankle to the thigh (100:67:30) accorded with the advised criterion by the European committee for standardization. The developed model can be used to predict and visualize the dynamic pressure and stress performances exerted by compression stocking in wear, and to optimize the material mechanical properties in stocking design, thus, helping us understand mechanisms of compression action and improving medical functions of GCS.

• Journal of Energy Engineering
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• v.12 no.4
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• pp.253-258
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• 2003

Manual type manifold gauge has been used for charging the refrigerant in the refrigeration systems. In this case, the refrigerant is released to the ambient during the hose-switching period. :he objectives of this study are to develop a novel automatic refrigerant charging system, and to quantify the effect of the automatic systems on the reduction of the non-condensable gas and the contamination of the compressor oil. The automatic charging system makes the pressure test, vacuum test, and refrigerant charging work very simple and easy because the charging hose does not have to be switched many times. It is found that the amount of water in the SiO$_2$and the compressor oil reduces to l/4 times of that for the manual type manifold gauge and the refrigerant is not released to the ambient at all when the automatic charging system is adopted.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.4
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• pp.381-385
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• 1996

This paper described to experiment and analyze for the characteristic of underwater airbubble curtain which was generated by the air - bubble curtain generating unit consisted with air compressor (290l/min x 1.5Kw) and air tank(10kgf/$cm^2$) in order to provide foundation source for guiding fish schools. To layout the air - bubble curtain was made vinyl hoses( $cm^2$ emitting air - pressure, the wider hole interval of hose drilled the higher air - bubble curtain could be formed, and then the horizontal length of air - bubble curtain could be prolonged 45% according to be inclined vertical angle of air - bubble generating hose.