• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.8
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• pp.739-744
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• 2009

Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In this paper, the degradation of rail pad properties as a function of their in-service life is studied with a view of developing a technique for predicting the optimum period of track maintenance with regard to pad replacement. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.100-105
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• 2021

This paper proposes the polydimethylsiloxane (PDMS) blade coating method for fabrication of paper-based analytical device (PAD) that is able to monitor the disease diagnosis and progress without special analytical equipment. The mold that has PAD design is easily modified by using laser cutting technique. And the fabricated mold is used for hydrophobic barrier formation by blade coating. We have optimized the stable formation of PDMS hydrophobic barrier as blade coating condition, which is established by analyzing the structure of the PDMS hydrophobic barrier and change of hydrophilic channel size as thickness of the ink and contact time with the chromatography paper. Based on optimal condition, we demonstrate that PAD as biosensor can apply to detect protein, glucose, and metal ion without special analysis equipment.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.211-218
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• 2000

Hot spot behaviors on the disk-pad contact surface during a braking operation have been analyzed for a ventilated disk brake using the finite element method. Hot spots which were studied using a coupled thermal-mechanical analysis technique are influenced by all of the mechanical, thermal, elastic and plastic processes that are involved in braking cycles, but their temperature gradients are most affected by rubbing speeds, braking forces, and design parameters between the disk and the pad. Undesirable hot spots that are generated by local thermoelastic instabilities are intended to be removed by optimized design parameters and material properties. In this study, a three-dimensional numerical method for the demonstration of hot spot behaviors has been applied to the rubbing surfaces between the disk and the pad.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.10
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• pp.935-945
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• 2014

This paper presents a new road generative system that employs a pad of preventive overspeed or tollgate. The system consists of pad, shaft, torsional damper, oneway-clutch, gear system, and electricity generator components. When the car driven through the road generation system, it occurred to surplus energy in the DC power. In order to maximize the power of electricity energy harvester, the simulation software is developed. It is used to determine parametric dimension for optimal design with the theoretically calculated results from the simulation software. The transient responses at the conditions of low and high vehicle speed are compared with the calculated results as torque, impact force, power, out energy etc. Consequently, before design a road generation system, the analysis of simulation results shows that the proposed concept and system has efficiency and confidence.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.213-220
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• 1999

The life data analysis of the system and component are useful to describe the result of reliability test in product life to satisfy customer's growing need and to change test specifications or design criteria by life data analysis. And vehicle durability tesr occurred market environment. In this study, a statistical analysis for the wear life of brake pad linings helped perform correlation procedure between vehicle durability test and market. B-life values of the brake pad wear life data from both vehicle durability test and marker usage were compared to determine acceleration of the test by the Weibull, normal and log-normal distribution. The acceleration coefficient of the vehicle durability test can access to evaluate design criteria of product and test specification.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.45-52
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• 2010

This paper presents a mathematical-physical model to predict the performance of a gas pusher used as a separation system powered by a gas generator. A quasi-steady model is used in order to aid ballistic analysis for a propellant actuated device(PAD). The empirical coefficients of heat loss and friction were determined from experiments. The analytical approach of combustion, flow and movement of a piston inside the chamber of the PAD, consisted of a gas generator and a gas pusher, was simulated by numerical method based on the grain configuration design of the gas generator. The prediction method developed can be usefully applied to the design of separation mechanism systems.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.445-454
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• 2017

Recently, playing musical instruments in the application or website which is a sort of playing has been catching on for ordinary people even though they don't know how to play musical instruments. It appears that such playing has randomness which is quite natural. Thus, 'Random operation method' which induces the observing audience and changes them to manage actively is developed and suggested for the image system in this paper by utilizing Launch Pad, based on theoretical background and case analysis. Step Sequencer was developed in two ways: the image system is realized with Step Sequencer by connecting external program or made as clips to arrange them for each key on Launch Pad and implement, which is keyboard launch type.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.748-751
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• 2010

To launch rocket on launch pad, propellants and gases are charged into the rocket by remote control system. Using pneumatic pressure-reducing regulators, kinds of gases with various pressure levels are supplied into launch pad. As most of operations for launching the vehicle are remotely controled in the launch control room, pressure pulsations due to rapidly gas supply at the upstream of regulators can make the required operating pressure range missed and cause damage to the regulators. In this paper, the optimum design methods of pressure regulators of pressure-reducing system on launch pad using high-pressure gases were investigated to solve the aforementioned problems and for stable gas supply to launch pad.

• Journal of Korean Association for Spatial Structures
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• v.23 no.1
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• pp.45-52
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• 2023

This study proposes an RCS composite damping device that can achieve seismic reinforcement of existing buildings by dissipating energy by inelastic deformation. A series of experiments assessing the performances of the rubber core pad, hysteretic steel slit damping device, and hybrid RCS damping device were conducted. The results showed that the ratios of the deviations to the mean values satisfied the domestic damping-device conformity condition for the load at maximum device displacement in each direction, at the maximum force and minimum force at zero displacement, as well as the hysteresis curve area. In addition, three analysis models based on load-displacement characteristics were proposed for application to seismic reinforcement design. In addition, the validity of the three proposed models was confirmed, as they simulated the experimental results well. Meanwhile, as the shear deformation of the rubber-core pad increased, the hysteretic behavior of super-elasticity greatly increased the horizontal force of the damping device. Therefore, limiting the allowable displacement during design is deemed to be necessary.

• Journal of Power System Engineering
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• v.12 no.3
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• pp.44-49
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• 2008

In this research, I would like to choose sliding distance and ventilated hole number which affect to the amount of wear of disk and pad as experiment conditions of 'the amount of wear' through wear test of motorcycle brake disk. Also, I analyze the amount of wear according to the variation of coefficient of friction by using design of experiment that is being widely used in diverse areas. With the tests of least, I present the correlation of each experiment condition. Therefore, I analyzed the variation of the amount of wear of disk and pad according to test factors such as ventilated hole number, applied load, sliding speed, and sliding distance in wear test of motorcycle brake disk by applying the design of experiment. Also, I analyzed quantitatively the influence of test factors through Taguchi Robust experimental design, response surface and examined the most suitable level and estimation of the amount of wear of disk. From these, I reached the following conclusions. response surface design, mathematical model was constructed about amount of wear of disk and pad. The amount of wear that decrease according to increase of ventilated hole number, and it's increase according to Increase of applied load, sliding speed, and sliding distance.