• Title, Summary, Keyword: displacement distribution

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Estimation of the Isolator Displacement for the Performance Based Design of Nuclear Power Plants (원전 적용을 위한 면진장치의 성능기반 설계 변위 추정)

  • Kim, Jung Han;Choi, In-Kil;Kim, Min Kyu
    • Journal of the Earthquake Engineering Society of Korea
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    • v.18 no.6
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    • pp.291-299
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    • 2014
  • There has been an increasing demand for introducing a base isolation system to secure the seismic safety of a nuclear power plant. However, the design criteria and the safety assessment methodology of a base isolated nuclear facility are still being developed. A performance based design concept for the base isolation system needs to be added to the general seismic design procedures. For the base isolation system, the displacement responses of isolators excited by the extended design basis earthquake are important as well as the design displacement. The possible displacement response by the extended design basis earthquake should be limited less than the failure displacement of the isolator. The failure of isolators were investigated by an experimental test to define the ultimate strain level of rubber bearings. The uncertainty analysis, considering the variations of the mechanical properties of isolators and input ground motions, was performed to estimate the probabilistic distribution of the isolator displacement. The relationship of the displacement response by each ground motion level was compared in view of a period elongation and a reduction of damping. Finally, several examples of isolator parameters are calculated and the considerations for an acceptable isolation design is discussed.

Characterization of Ceramic Membranes by Gas-Liquid Displacement Porometer and Liquid-Liquid Displacement Porometer (Gas-Liquid Displacement Porometer와 Liquid-Liquid Displacement Porometer를 이용한 세라믹 분리막 특성 분석)

  • Kim, Yeo-Jin;Kim, Seong-Joong;Kim, Jeong;Jo, Yeong-Hoon;Park, Hosik;Lee, Pyung-Soo;Park, You-In;Park, Ho-Bum;Nam, Seung-Eun
    • Membrane Journal
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    • v.27 no.3
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    • pp.263-272
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    • 2017
  • There are several different methods to characterize membrane pore size distribution, however, it is yet difficult to accurately measure pore size range of 10-50 nm. In this work, we employed gas-liquid displacement porometer (GLDP) and liquid-liquid displacement porometer (LLDP) to characterize in-house alumina hollow fiber membrane (K-100) and commercial membranes (A-100, A-20) that exhibit pore sizes between 10-100 nm. GLDP method was more suitable for measuring the maximum pore size, and the measured mean pore size of the membranes by LLDP were better correlated with water permeability and solute rejection. It was determined that LLDP is effective for measuring pore sizes between 10-50 nm; however, the method holds intrinsic disadvantages such as low precision and high sensitivity compared to that of GLDP. Nevertheless, it is expected that the recently commercialized LLDP technique can provide useful data that other methods cannot.

Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading

  • Mishra, Manish;Ozawa, Shogo;Masuda, Tatsuhiko;Yoshioka, Fumi;Tanaka, Yoshinobu
    • The Journal of Advanced Prosthodontics
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    • v.3 no.3
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    • pp.140-144
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    • 2011
  • PURPOSE. Finite element study on the effect of abutment length and material on implant bone interface against dynamic loading. MATERIALS AND METHODS. Two dimensional finite element models of cylinderical implant, abutments and bone made by titanium or polyoxymethylene were simulated with the aid of Marc/Mentat software. Each model represented bone, implant and titanium or polyoxymethylene abutment. Model 1: Implant with 3 mm titanium abutment, Model 2: Implant with 2 mm polyoxymethylene resilient material abutment, Model 3: Implant with 3 mm polyoxymethylene resilient material abutment and Model 4: Implant with 4 mm polyoxymethylene resilient material abutment. A vertical load of 11 N was applied with a frequency of 2 cycles/sec. The stress distribution pattern and displacement at the junction of cortical bone and implant was recorded. RESULTS. When Model 2, 3 and 4 are compared with Model 1, they showed narrowing of stress distribution pattern in the cortical bone as the height of the polyoxymethylene resilient material abutment increases. Model 2, 3 and 4 showed slightly less but similar displacement when compared to Model 1. CONCLUSION. Within the limitation of this study, we conclude that introduction of different height resilient material abutment with different heights i.e. 2 mm, 3 mm and 4 mm polyoxymethylene, does not bring about significant change in stress distribution pattern and displacement as compared to 3 mm Ti abutment. Clinically, with the application of resilient material abutment there is no significant change in stress distribution around implant-bone interface.

A FINITE ELEMENT ANALYSIS ON THE EFFECT OF THE HEADGEAR IN HUMAN MAXILLA (HEAD GEAR가 상악골에 미치는 영향에 관한 유한요소법적 분석)

  • Lee, In-Soo;Sohn, Byung-Hwa
    • The korean journal of orthodontics
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    • v.15 no.2
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    • pp.211-227
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    • 1985
  • The purpose of this study was to analyze the stress distribution and the displacement in the maxillary complex after the application of the three kinds of the head gear. (high pull head gear, straight pull head gear, cervical pull head gear.) Orthopedic force, 300 gram, was applied to the maxilla of the dry human skull in a high, straight and cervical direction. The stress distribution and the displacement within the maxillary complex was analyzed by a 3-dimensional finite element method. The results were as follow: 1. In won, the stress of conical pull head gear was the greatest stress and straight pull head gear was the medium stress and high pull head gear was the least stress. 2. The compressive stress was observed on the anterior portion of premaxilla, especially anterior nasal spine area, when the three kinds of head gear were applied to the dry kuman skull. 3. It appeared that the stress of the anterior portion of the zygomatic bone was greater than the posterior portion in the case of three kinds of head gear application and compressive stress was noted only at the below of the frontozygomatic suture of the zygomatic bone. 4. The backward, upward, sideward displacement of the alveolar area was observed in a high pull head gear application but in the case of straight pull head gear and cervical pull head gear application, the backward, downward, sideward displacement was observed. 5. The forward, downward, sideward displacement was observed on the midpalatine suture and premaxilla on the sagittal plane and transverse palatine suture in the case of three kinds of headgear application.

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The Effect of Temperature on the Process of Immiscible Displacement in Pore Network (공극 구조 내 비혼성 대체 과정에서 주입 온도가 유체 거동에 미치는 영향)

  • Park, Gyuryeong;Kim, Seon-ok;Lee, Minhee;Wang, Sookyun
    • Economic and Environmental Geology
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    • v.51 no.3
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    • pp.223-232
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    • 2018
  • The viscous force of fluids and the capillary force acting on the pore network of the porous media are important factors determining the immiscible displacement during geological $CO_2$ sequestration, these were directly affected by geological formation conditions and injection conditions. This study aimed to observe the migration and distribution of injected fluid and pore water, and quantitatively investigate displacement efficiency on various injection temperatures. This study aimed to perform micromodel experiments by applying n-hexane used as a proxy fluid for supercritical $CO_2$. In this study, immiscible displacement process from beginning of n-hexane injection to equilibrium of the distribution of the n-hexane and pore water was observed. The images from experiment were used to observe the displacement pattern and estimate the areal displacment efficiency of the n-hexane. For investigate the affects of the injection temperatures on the migration in macroscopic, migration of n-hexane in single pore was analyzed. The measurement revealed that the displacement efficiency at equilibrium state decreases as the temperature increases. The result from experiments indicate that the temperatures can affect the displacement pattern by changing the viscous forces and the capillary forces. The experimental results could provide important fundamental information on reservoir conditions and fluid injection conditions during geological $CO_2$ sequestration.

A Simulation on the Displacement Stress of Cement in Porcelain Insulators for Transmission Line (송전용 자기재 애자의 시멘트 변위 응력에 관한 시뮬레이션)

  • Han, S.W.;Cho, H.G.;Woo, B.C.;Jung, G.C.;Lee, D.I.;Choi, I.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.476-479
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    • 2002
  • The ageing cause in many porcelain suspension insulators which occur on transmission and distribution line with dead-end stings is mechanical stress in interface between porcelain and cement materials. It is known that the principal mechanical stress which give electrical failure is the results of the displacement is due to cement growth. We studied the effect of cement displacement resulting environmental ageing parameters on porcelain insulator mechanical properties for transmission line by simulation (ANSYS/NASTRAN program) and test methods. These simulation analysis and experimental results show that cement volume growth affects severely to be mechanical failure ageing.

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A Study on the Strain Analysis of Cracked Plate by Electronic Speckle Pattern Interferometry (전자처리 Speckle Pattern 간섭법에 의한 균열평판의 Strain 해석에 관한 연구)

  • 김경석;양승필
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.6
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    • pp.1382-1390
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    • 1995
  • Electronic Speckle Pattern Interferometry (ESPI) with a CW laser, a video system and an image processor was utilized to measure the in-plane displacement. Unlike traditional strain gauges or Moire method. ESPI method measure the in-plane displacement on real time with out any surface preparation on surface attachment. The specimen has a crack of 10*0.1 mm in the middle of plate and strain gauge was also attached on that surface to compare with ESPI method. This study reveled the ESPI method to measure the displacement and distribution of strain in the specimen. It was shown in tensile tests that the measurement by ESPI method was comparable with strain gauge.

Pressure Control of Electro-Hydraulic Variable Displacement Pump Using Genetic Algorithms (GA를 이용한 전기유압식 가변펌프의 압력제어)

  • 안경관;현장환;조용래;오범승
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.9
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    • pp.48-55
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    • 2004
  • This study presents a genetic algorithm-based method fur optimizing control parameters in the pressure control of electro-hydraulic pump with variable displacement. Genetic algorithms are general-purpose optimization methods based on natural evolution and genetics and search the optimal control parameters maximizing a measure that evaluates the performance of a system. Four control gains of the PI-PD cascade controller for an electro-hydraulic pressure control system are optimized using a genetic algorithm in the experiment. Optimized gains are confirmed by inspecting the fitness distribution which represents system performance in gain spaces. It is shown that genetic algorithm is an efficient scheme in optimizing control parameters of the pressure control of electro-hydraulic pump with variable displacement.

A Technique for Measuring Vibration Displacement Using Camera Image (카메라 영상을 이용한 진동변위 측정)

  • Son, Ki-Sung;Jeon, Hyeong-Seop;Park, Jin-Ho;Park, Jong Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.9
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    • pp.789-796
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    • 2013
  • Vibration measurements using image processing have been studied by many researchers as it can remotely measure vibration displacements at multiple points simultaneously. It is difficult, however, to obtain accurate displacement from the measured image signals because the resolution of image data is dependent on camera performance and normally lower than that of vibration transducer directly measured. This paper suggests the enhanced technique for vibration displacement measurement by applying the expected value of edge probability distribution to the varying pixel points in the image. The method can both increase the resolution limit of camera image and decrease the measurement errors. The working performance of the proposed technique is verified applying to the vibration measurement of a rotating machine.

A Study on Dose Sensitivity according to Position Variance in Extremities Radiation Therapy with Water Bolus (사지의 방사선 치료에 사용하는 water bolus의 적용 시 치료부위의 위치 변화에 따른 방사선 선량분포의 민감도 연구)

  • Seo, Jeong Min
    • Journal of the Korea Safety Management and Science
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    • v.17 no.4
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    • pp.199-206
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    • 2015
  • The purpose of this study was to investigate radiation dose sensitivity due to displacement of human extremities in the water bolus box on radiation therapy. Water bolus box and human thigh with femur bone were constructed in computerized radiation therapy planning system to verify the absorbed dose. Two 6MV X-ray beams were irradiated bilaterally into water bolus box and then radiation dose were calculated each situation at displacement of middle axis of thigh from the center in water bolus box to right and left direction. Absorbed dose of thigh and femur bone increased by the distance of displacement. The maximum dose of thigh even increased 20% over than prescribed dose. This is in contrast to conventional concept of dose distribution in water bolus box. Based on this result, displacement of body site in the water bolus box have to be averted during radiation therapy.