• Title/Summary/Keyword: Valve-point

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NUMERICAL METHOD FOR A 2NTH-ORDER BOUNDARY VALUE PROBLEM

  • Xu, Chenmei;Jian, Shuai;Wang, Bo
    • Journal of the Korean Mathematical Society
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    • v.50 no.4
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    • pp.715-725
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    • 2013
  • In this paper, a finite difference scheme for a two-point boundary value problem of 2nth-order ordinary differential equations is presented. The convergence and uniqueness of the solution for the scheme are proved by means of theories on matrix eigenvalues and norm. Numerical examples show that our method is very simple and effective, and that this method can be used effectively for other types of boundary value problems.

유압펌프에서 발생되는 고주파 유량맥동의 고응답 계측

  • 이상기;김도태
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.04b
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    • pp.267-272
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    • 1995
  • The paper describes an approach for measuring flow ripple generated by oil hydraulic axial piston pumps. Flow ripple has periodic waveforms due to the cyclic nature of a pump's operation, and interacts with the connected hydraulic systems such as pipes and components to produce a pressure ripple, also known as fluid-borne noise. It is indispensable to measure a flow ripple because increasing of vibration and noise caused by a flow ripple has become a point to be considered and has need of solving these problems. The measurement of flow ripple with high frequencies from oil hydraulic axial piston pumps is msde by using the remote instantaneous flow rate measurement method. As a result, the reverse flow through the relief groove in valve plate has an important effect upon a flow ripple generated by a pumps.

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Development of Sorting Machine for Photo Diode and Improvement of Sorting Precision by using Machine Vision (광 다이오드 분류장치 및 비젼을 이용한 정밀도 향상)

  • Ryuh B.S.;Park S.M.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.153-154
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    • 2006
  • Development of sorting machine for photo diode and its control system is addressed. The sorting machine for optical communication device requires high positional precision because the alignment is one of the most important point in the sorting process. This sorting method describes how to detect the target chip's angle and position from the wafer. The machine vision system is used for the feedback control. This sorting machine is implemented by motion controller, machine vision and various solenoid valve and is interfaced with RS-232c, GPIB and PCI communication. This system gets the position accuracy within $1{\mu}m$ with our experiments.

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Classification of Somatotype of the Elderly Women by the Lateral View

  • Yoo, Hee Sook
    • Fashion & Textile Research Journal
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    • v.2 no.5
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    • pp.383-390
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    • 2000
  • The purpose of this study was to classify the somatotype of elderly women and to extract discriminant factors of the classification. The subjects were 218 elderly women aged 60-85 years old. Data were collected from 46 anthropometric and photographic measurements of each subject and analyzed by frequencies, crosstabs, analysis of variance and discriminant analysis. The somatotype was classified into 5 types according to the lateral view. The normal type was defined as the type which the plumb line passes through the cervicale and the lateral malleolus. The lean-back type positioned the plumb line more posteriorly than normal type. The swayback type positioned the plumb line at about the same line as the lean-back type, but curvature of lateral view was prominent. The lean-forward type I and II positioned the plumb line more anteriorly than normal, but the spinal curvature of the type II disappeared. As the result of discriminant analysis, significant discriminant factors of anthropometric measurement were cervicale height, anterior waist height, neck point to posterior waist length, anterior waist length. Photographic measurement were C valve, D value, ∠${\alpha}$ and ∠${\beta}$.

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An Analysis of Diesel Engine Cylinder Block-Liner-Gasket-Head Compound by Finite Element Method (유한요소법을 이용한 디젤 엔진의 실린더블록-라이너-가스킷-에드 구조물에 대한 해석)

  • 김주연;안상호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.3
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    • pp.147-158
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    • 1997
  • This paper presents the analysis technique and procedure of main engine components-cylinder block, cylinder liners, gasket and cylinder head-using the finite element method, which aims to assess mainly the potential of lower oil consumption in a view point of engine design and to decide subsequently the accuracy of engine design which was done. The F.E. model of an engine section consisting of one whole cylinder and two adjacent half cylinders is used, whereby the crankcase is cut off at the block bottom deck. By means of a 3-dimensional F.E. model-including cylinder block, liners, gasket, cylinder head, bolts and valve seat rings as separate parts a linear analysis of deformations and stresses was performed for three different loading conditions;assembly, thermal and gas loads. For the analysis of thermal boundary conditions also the temperature field had to be evaluated in a subsequent step.

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Regeneration of Burner Type Diesel Particulate Trap System Through Active Exhaust Gas Feeding (배기 가스 유량 제어를 이용한 버너방식 디젤 입자상물질 제거 장치의 재생)

  • 김재업;박동선;이만복;김응서
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.1
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    • pp.1-13
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    • 1997
  • The key point that guarantees the durability of the ceramic monolith filter is to lower peak temperature and temperature gradient inside filter during regeneration. The control of the exhaust gas flow rate into the filter, by the bypass technique of the exhaust gas, enables the gas temperature in filter to be constant for regeneration. A couple of methods, which are the ON/OFF and PID control of the bypass valve, were used for feedback control of the gas temperature. These techniques showed that the ceramic filter was regenerated perfectly under the peak temperature and peak temperature gradient limitations for durability.

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Synthesis and Characterization of Ti-B System Ceramics Prepared by Self-Propagating High-Temperature Synthesis Method (SHS법에 의한 Ti-B 계 세라믹스의 합성 및 소결특성)

  • 이형복;최일선;오응주;여철현
    • Journal of the Korean Ceramic Society
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    • v.28 no.3
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    • pp.234-242
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    • 1991
  • Ti-B system ceramics were prepared by the self-propagating high-temperature synthesis method from the mixture of metal titanium and boron powders The major crystalline phase as a function of boron content was TiB for mixtures containing 0.5 or 1.0mol B, and TiB2 for these containing over 1.3mol B. The combustion mode observed by a high-speed camera was steady-state. The Combustion velocity increased with increasing the boron content. Sintered TiB2 specimen showed the density of 97% of theoretical valve, Vicker's hardness of 2250kg/㎟ for 0.2kg load and three-point-flexure strength of 500MPa.

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Optimal Design of Hydraulic System Using the Complex Method (컴플렉스법에 의한 유압시스템의 최적 설계)

  • Lee S.R.;Lee Y.B.;Park J.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.1 no.4
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    • pp.1-8
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    • 2004
  • The optimum design parameters of several hydraulic systems are obtained using the complex method that is one kind of constrained direct search method. First, the parameters of lead-lag controller of the direct drive servovalve is designed using the complex method to satisfy the steady-state error requirement. Second, the optimum locating point of hydraulic cylinder Is determined to minimize the cylinder force in the operation range of rotational sluice gate. For the third application case, the optimum piston area of hydraulic cylinder is determined to minimize the man power to elevate the manually operated sluice gate.

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Simulations for an ASCU of a Train Brake including a Pneumatic Model (공압모델이 포함된 철도차량 제동 ASCU 시뮬레이션)

  • Kim, Ho-Yeon;Kang, Chul-Goo
    • 유공압시스템학회:학술대회논문집
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    • 2010.06a
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    • pp.93-97
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    • 2010
  • Wheel skids may occur during train operations due to low adhesion at the wheel-rail contact point abnormally, and the skids, in turn, result in flats appearing on the wheels, which affect safety and ride comfort significantly. Thus, anti-skid control has a crucial role for safe braking and prevention from flats that could cause a disastrous train accident. This paper presents simulation studies on an anti-skid control unit (ASCU) with a brake system of a rolling stock including a pneumatic model for brake power supply and dump valve operation.

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Real-time Active Control by Optical Analysis of Combustion Flame for Boiler Sysetm (화염의 광학적 분석에 의한 보일러의 실시간 능동 제어)

  • Choo, Seong-Ho;Yi, Choong-Hwan
    • Proceedings of the KIEE Conference
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    • 2007.10a
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    • pp.287-288
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    • 2007
  • This paper is for a Real-time Active Control System to operate a boiler. By sensing of flame we wanted to get status of a furnace as many as possible, like load, efficiency, and/or amount of pollutant. These data can be used to make optimal running point by controlling the ratio of air and fuel. So the last object is to make a closed actual control loop from optical head to valve controllers. The first job was to design and to develop a optical data acquisition system. including optical sensor module. And we gathered flame data in variable situations for taking the trend of flame against burning environment. Currently we are developing a general system model, designing some control strategy and testing this active control system.

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