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A Study on Friction Coefficient Prediction of Hydraulic Driving Members by Neural Network (신경회로망에 의한 유압구동 부재의 마찰계수 추정 에 관한 연구)

  • 김동호
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.5
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    • pp.53-58
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    • 2003
  • Wear debris can be collected from the lubricants of operating machinery and its morphology is directly related to the fiction condition of the interacting materials from which the wear particles originated in lubricated machinery. But in order to predict and estimate working conditions, it is need to analyze the shape characteristics of wear debris and to identify. Therefore, if the shape characteristics of wear debris is identified by computer image analysis and the neural network, The four parameter (50% volumetric diameter, aspect, roundness and reflectivity) of wear debris are used as inputs to the network and learned the friction. It is shown that identification results depend on the ranges of these shape parameters learned. The three kinds of the wear debris had a different pattern characteristic and recognized the friction condition and materials very well by neural network. We resented how the neural network recognize wear debris on driving condition.

Image Analysis of Wear Debris on Operating Condition of Lubricated Machine Surface (윤활운동면의 작동상태에 따른 마멸분 화상해석)

  • 서영백;박흥식;전태옥;진동규;김형자
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.60-67
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    • 1996
  • This paper was undertaken to analyze the morphology of wear debris on operating condition of lubricated machine surfaces. The lubricating wear test was carried out under different experimental conditions using the wear test device was made in our laboritory and wear testing spcimen of the pin on disk type was rubbed in paraffine series base oil, by varying specimen, applied load, sliding distance. The four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) to describe morphology of wear debris have been developed and are outlined in the paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology for machine condition monitoring.

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컴퓨터 영상처리에 의한 윤활시스템의 상태진단

  • 서영백;박흥식;전태옥;이충엽
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.224-231
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    • 1997
  • Microscopic examination for the morphological estimation of wear debris on the oil-lubrcated moving system is an accepted method for machine condition and fault diagnosis. However wear particle anaysis has not been widely accepted industry because it is dependent on expert interpretation of particle morphology and relies on subjective assessment criteria. This paper was undertaken to estimate the morphology of wear debris on the oil-lubricated movig system by computer image analysis. The wear test was performed under different sliding conditions using a wear test device made in our laboratory and wear testing specimen of the pin-on-disk-type was rubbed in pararline series base oil. In order to describe characteristics of debris of various shape and size, four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) have been developed and outlined in the paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology in machine condition monitoring.

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Analysis of Wear Debris for Operating Condition Evaluation of Lubricated Machine Surface (기계윤활면의 작동상태 평가를 위한 마멸분 해석)

  • 서영백;박흥식;전태옥;이광영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.85-89
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    • 1996
  • This paper was undertaken to analyze the morphology of wear debris for operating condition evaluatio of lubricated machine surfaces. The lubricating wear test was carried out under different experimental conditions using tile wear test device was made in our laboritory and wear testing spcimen of the pin on disk type was rubbed in paraffine series base oil, by varying specimen, applied load, sliding distance. The four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) to describe morphology of wear debris have been developed and are outlined in tile paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology in machine condition monitoring

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Wear Debris Identification of the Lubricated Machine Surface with Neural Network Model (신경회로망 모델을 이용한 기계윤활면의 마멸분 형태식별)

  • 박홍식;서영백;조연상
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.3
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    • pp.133-140
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    • 1998
  • The neural network was applied to identify wear debris generated from the lubricated machine surface. The wear test was carried out under different experimental conditions. In order to describe characteristics of debris of various shapes and sizes, the four shape parameter(50% volumetric diameter, aspect, roundness and reflectivity) of wear debris are used as inputs to the network and learned the friction condition of five values(material 3, applied load 1, sliding distance 1). It is shown that identification results depend on the ranges of these shape parameter learned. The three kinds of the wear debris had a different pattern characteristics and recognized the friction condition and materials very well by neural network.

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Analysis of Wear Debris for Machine Condition Diagnosis of the Lubricated Moving Surface (기계윤활 운동면의 작동상태 진단을 위한 마멸분 해석)

  • Seo, Yeong-Baek;Park, Heung-Sik;Jeon, Tae-Ok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.5
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    • pp.835-841
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    • 1997
  • Microscopic examination of the morphology of wear debris is an accepted method for machine condition and fault diagnosis. However wear particle analysis has not been widely accepted in industry because it is dependent on expert interpretation of particle morphology and subjective assessment criteria. This paper was undertaken to analyze the morphology of wear debris for machine condition diagnosis of the lubricated moving surfaces by image processing and analysis. The lubricating wear test was performed under different sliding conditions using a wear test device made in our laboratory and wear testing specimen of the pin-on-disk-type was rubbed in paraffine series base oil. In order to describe characteristics of debris of various shape and size, four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) have been developed and outlined in the paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology in machine condition monitoring, thus to overcome many of the difficulties in current methods and to facilitate wider use of wear particle analysis in machine condition monitoring.

Treatment Planning for Minimizing Carotid Artery Dose in the Radiotherapy of Early Glottic Cancer (조기 성문암의 방사선치료에서 경동맥을 보호하기 위한 치료 계획)

  • Ki, Yang-Kan;Kim, Won-Taek;Nam, Ji- Ho;Kim, Dong-Hyun;Lee, Ju-Hye;Park, Dal;Kim, Don-Won
    • Radiation Oncology Journal
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    • v.29 no.2
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    • pp.115-120
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    • 2011
  • Purpose: To examine the feasibility of the treatment planning for minimizing carotid artery dose in the radiotherapy of early glottic cancer. Materials and Methods: From 2007 to 2010, computed tomography simulation images of 31 patients treated by radiotherapy for early glottic cancer were analyzed. The virtual planning was used to compare the parallel-opposing fields (POF) with the modified oblique fields (MOF) placed at angles to exclude the ipsilateral carotid arteries. Planning target volume (PTV), irradiated volume, carotid artery, and spinal cord were analyzed at a mean dose, $V_{35}$, $V_{40}$, $V_{50}$ and with a percent dose-volume. Results: The beam angles were arranged 25 degrees anteriorly in 23 patients and 30 degrees anteriorly in 8 dose-volume of carotid artery shows the significant difference (p<0.001). The mean doses of carotid artery were 38.5 Gy for POF and 26.3 Gy for MOF and the difference was statistically significant (p=0.012). Similarly, $V_{35}$, $V_{40}$, and $V_{50}$ also showed significant differences between POF and MOF. Conclusion: The modified oblique field was respected to prevent a carotid artery stenosis and reduce the incidence of a stroke based on these results.

Change of Piping-System Dynamics with Installation of Pogo Suppression Device (포고억제장치 설치에 따른 배관계 동특성 변화)

  • Lee Jun Kyoung;Lee Sang Yong;Lee Han Ju;Oh Seung Hyub
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.2
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    • pp.32-39
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    • 2005
  • The effectiveness of the pogo suppression device (PSD) on the response of the piping system simulating the fuel (or oxidizer) supply lines of the rocket engines was investigated. The system response defined as the ratio of the flow rate to the pressure in the main tube was obtained for various PSD gas volumes $((0\~2)\times10^{-3}m^3)$ and three different baffle hole diameters (5, 50, 115mm). Existence of a gas volume in the PSD reduced the system resonance frequency. With a larger gas volume, the resonance frequency became lower, but only slightly, while the fluctuations of the main tube pressure and the flow rate damped down considerably. The resonance frequency decreased with the increase of the PSD inlet restriction (or the decrease of the baffle hole diameter), though slightly. However, with a larger inlet restriction, the PSD pressure wave showed a delayed response with the smaller amplitude compared to the pressure variation in the main tube.

Use of Respiratory Motion Reduction Device (RRD) in Treatment of Hepatoma (간암의 방사선치료 시 호흡운동 감소장치(respiratory motion reduction device, RRD)의 유용성에 관한 연구)

  • Lee Suk;Seong Jinsil;Kim Yong Bae;Cho Kwang Hwan;Kim Joo Ho;Jang Sae Kyung;Kwon Soo Il;Chu Sung Sil;Suh Chang Ok
    • Radiation Oncology Journal
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    • v.19 no.4
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    • pp.319-326
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    • 2001
  • Purpose : Planning target volume (PTV) for tumors in abdomen or thorax includes enough margin for breathing-related movement of tumor volumes during treatment. Depending on the location of the tumor, the magnitude of PTV margin extends from 10 mm to 30 mm, which increases substantial volume of the irradiated normal tissue hence, resulting in increase of normal tissue complication probability (NTCP). We developed a simple and handy method which can reduce PTV margins in patients with liver tumors, respiratory motion reduction device (RRD). Materials and methods : For 10 liver cancer patients, the data of internal organ motion were obtained by examining the diaphragm motion under fluoroscope. It was tested for both supine and prone position. A RRD was made using MeV-Green and Styrofoam panels and then applied to the patients. By analyzing the diaphragm movement from patients with RRD, the magnitude of PTV margin was determined and dose volume histogram (DVH) was computed using AcQ-Plan, a treatment planning software. Dose to normal tissue between patients with RRD and without RRD was analyzed by comparing the fraction of the normal liver receiving to $50\%$ of the isocenter dose. DVH and NTCP for normal liver and adjacent organs were also evaluated. Results : When patients breathed freely, average movement of diaphragm was $12{\pm}1.9\;mm$ in prone position in contrast to $16{\pm}1.9\;mm$ in supine position. In prone position, difference in diaphragm movement with and without RRD was $3{\pm}0.9\;mm$ and 12 mm, respectively, showing that PTV margins could be reduced to as much as 9 mm. With RRD, volume of the irradiated normal liver reduced up to $22.7\%$ in DVH analysis. Conclusion : Internal organ motion due to breathing can be reduced using RRD, which is simple and easy to use in clinical setting. It can reduce the organ motion-related PTV margin, thereby decrease volume of the irradiated normal tissue.

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Estimation of Mechanical Properties of Tungsten-Fiber-Reinforced Ti-MMCs by Hot Isostatic Pressing (HIP 처리 티타늄기 MMC 의 기계적 특성평가)

  • Son, Sun-Young;Nishida, Shin-Ichi;Lee, Jong-Hyung;Kim, Young-Tae;Lee, Do-Kyung;Son, Yong-Jea;Jang, Hyun-Duck
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.4
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    • pp.407-412
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    • 2010
  • The objective of this study is the estimation of the mechanical properties of HIP-treated MMCs by an optimized manufacturing process. The Ti-MMCs were fabricated by HIP and rotary swaging (RS) for secondary processing. The Ti-MMCs with different tungsten fiber contents of 0, 6, 9, and 12 vol% were subjected to tensile tests, fatigue tests, and hardness tests. The results show that the hardness values of Ti-MMCs increased with the increasing volume percent of tungsten fibers, the tensile strength increased by approximately 50% (specific strength: 38%) at the 9 vol%. The value of tungsten-fiber orientation F affects the tensile strength. The fatigue strengths of the Ti-MMCs did not improve. HIP is a useful manufacturing method for Ti-MMCs and RS is an important process for improving fiber orientation during secondary processing.