• Title, Summary, Keyword: volumetric measurements

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Effects of the Method of Changing Compression Ratio on Engine Performance in an SI Engine (가솔린 엔진에서 압축비 변경 방법이 성능에 미치는 영향)

  • 이원근;엄인용
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.27-33
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    • 2001
  • In this study, it is observed that the distribution of combustion chamber volume affects the volumetric efficiency. The distribution ratio was adjusted by controlling combustion chamber volume of head and piston bowl one. Four cases were investigated, which are the combination of different distribution ratios and different compression ratios (9.8-10.0). A commercial SOHC 3-valve engine was modified by cutting the bottom face of the head and/or replacing the piston by the one that has different volume. The result shows that the less the head side volume, the more volumetric efficiency is achieved under the same compression ratio. It is also observed that increasing volumetric efficiency results in early knock occurrence due to increased "real" compression ratio. To consider reliability in estimating the volumetric efficiency, we examined the sensitivity of the AFR equation to possible errors in emission measurements. It is shown that the volumetric efficiency, which is calculated by measuring AFR and fuel consumption, can be controlled in 1% error. 1% error.

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Estimation and Evaluation of Volumetric Position Errors for Multi-axis Machine Tools (다축공작기계의 공간오차 예측 및 검증)

  • Hwang, Jooho;Nguyen, Ngoc Cao;Bui, Chin Ba;Park, Chun-Hong
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.23 no.1
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    • pp.1-6
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    • 2014
  • This paper describes a method of estimating and evaluating the volumetric errors of multi-axis machine tools. The estimation method is based on a generic model that was developed from conventional kinematic error models for the geometric and thermal errors to help predict the volumetric error easily in various configurations. To demonstrate the advantages of the model, an application in the early stages of a five-axis machine tool design is presented as an example. The model was experimentally evaluated for a four-axis machine tool by using the data from ISO230-6 and R-test measurements to compare the estimated and measured volumetric errors.

Quantification of Volumetric In-Cylinder Flow of SI Engine Using 3-D Laser Doppler Velocimetry ( II )

  • Yoo, Seoung-Chool
    • The KSFM Journal of Fluid Machinery
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    • v.10 no.4
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    • pp.47-54
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    • 2007
  • Simultaneous 3-D LDV measurements of the in-cylinder flows of three different engine setups were summarized for the quantification of the flow characteristics in each vertical or horizontal plane, and in entire cylinder volume. The ensemble averaged-velocity, tumble and swirl motions, and turbulent kinetic energy during the intake and compression strokes were examined from the measured velocity data (approximately 2,000 points for each engine setup). The better spatial resolution of the 3-D LDV allows measurements of the instantaneous flow structures, yielding more valuable information about the smaller flow structures and the cycle-to-cycle variation of these flow patterns. Tumble and swirl ratios, and turbulent kinetic energy were quantified as planar and volumetric quantities. The measurements and calculation results were animated for the visualization of the flow, and hence ease to analysis.

Measurements of Permeability Characteristics for Unsaturated Weathered Soils (불포화 풍화토의 투수특성 측정)

  • Ryu, Ji-Hyeop
    • Journal of Korea Water Resources Association
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    • v.33 no.1
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    • pp.133-142
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    • 2000
  • Series of tests were carried out to study permeability characteristics of unsaturated soils. The weathered soils taken from Inju, Sungwhan, and Kuri, were selected to have different amount of fine grained soils in order to find a possible correlation between the unsaturated permeability behavior and fine grained soils contents. Measurements of permeability for unsaturated soils were performed with a newly developed apparatus, which modeled after Klute's apparatus(1965a). The apparatus was designed to measure volumetric water content and permeability by applying incremental suction pressure. Permeability and volumetric water content of unsaturated soils generally decreased as density of the soil increased. The relationship between volumetric water content and permeability was not related to the fine grained soils contents because the plots scattered widely. By comparing volumetric water content with permeability, empirical parameters A and B could be determined, which made to be possible to predict unsaturated permeability from soil-moisture characteristics.

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터빈 유량계를 사용한 이상유동의 측정

  • Sim, Jae-U
    • Journal of Ocean Engineering and Technology
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    • v.12 no.2
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    • pp.147-152
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    • 1998
  • In this study turbine flowmeters were used to predict volumetric flow rate of each phase in two-phase, gas-liquid, flowing in a vertical tube. To determine volumetric flow rates of two-phase, air-water, flowing vertically upward through the polycarbonate tube(57mm ID-inside diameter), two turbine flow meters were used. For void fraction measurements, two gamma densitometers were used at each location of the turbine flow meter, one at the upstream and the other at the downstream. It was determined that the turbine flowmeter's outputs were a function of actual volumetric flow rate of each of the two phases. A two-phase flow model was developed.

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Importance of Volumetric Measurement Processes in Oncology Imaging Trials for Screening and Evaluation of Tumors as Per Response Evaluation Criteria in Solid Tumors

  • Vemuri, Ravi Chandra;Jarecha, Rudresh;Hwi, Kim Kah;Gundamaraju, Rohit;MaruthiKanth, Aripaka;Kulkarni, AravindRao;Reddy, Sundeep
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.5
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    • pp.2375-2378
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    • 2014
  • Cancer, like any disease, is a pathologic biological process. Drugs are designed to interfere with the pathologic process and should therefore also be validated using a functional screening method directed at these processes. Screening for cancers at an appropriate time and also evaluating results is also very important. Volumetric measurement helps in better screening and evaluation of tumors. Volumetry is a process of quantification of the tumors by identification (pre-cancerous or target lesion) and measurement. Volumetric image analysis allows an accurate, precise, sensitive, and medically valuable assessment of tumor response. It also helps in identifying possible outcomes such disease progression (PD) or complete response as per Response Evaluation Criteria in Solid Tumors (RECIST).

Identification on the Three-Dimensional Vortical Structures of Impeller Flow by a Multi-Plane Stereoscopic PIV Method (스테레오 PIV 기법에 의한 임펠러 와류유동의 3차원 구조측정)

  • Yoon, Sang-Youl;Kim, Kyung-Chun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.6
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    • pp.773-780
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    • 2003
  • The three-dimensional spatial structures of impeller flow created by a six bladed Rushton turbine have identified based on the volumetric velocity information from multi-plane stereoscopic PIV measurements. A total of 10 planes with 2 mm space and a 50 mm by 64 mm size of the field of view were targeted. To reduce the depth of focus, we adopted an angle offset configuration which satisfied the Scheimpflug condition. The distortion compensation procedure was utilized during the in situ calibration. Phase-locked instantaneous data were ensemble averaged and interpolated in order to obtain mean 3-D. volumetric velocity fields on a 60 degree sector of a cylindrical ring volume enclosing the turbine blade. Using the equi-vorticity surface rendering, the spatial structure of the trailing vortices was clearly demonstrated. Detail flow characteristics of the radial jet reported in previous studies of mixer flows were easily identified.

Identification on the Three-Dimensional Vortical Structures of Impeller Flow by a Multi-Plane Stereoscopic PIV Method (스테레오 PIV 기법에 의한 임펠러 와류유동의 3차원 구조측정)

  • Yoon, Sang-Youl;Kim, Kyung-Chun
    • Proceedings of the KSME Conference
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    • pp.690-695
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    • 2001
  • The three-dimensional spatial structures of impeller flow created by a six bladed Rushton turbine have identified based on the volumetric velocity information from multi-plane stereoscopic PIV measurements. A total of 10 planes with 2 mm space with a 50 mm by 64 mm size of the field of view were targeted. To reduce the depth of focus, we adopted an angle offset configuration which satisfied the Scheimpflug condition. The distortion compensation procedure was utilized during the in situ calibration. Phase-locked instantaneous data were ensemble averaged and interpolated in order to obtain mean 3-D, volumetric velocity fields on a 60 degree sector of a cylindrical ring volume enclosing the turbine blade. Using the equi-vorticity surface rendering, the spatial structure of the trailing vortices was clearly demonstrated. Detail flow characteristics of the radial jet reported in previous studies of mixer flows were easily identified.

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Two-dimensional and volumetric airway changes after bimaxillary surgery for class III malocclusion

  • Vaezi, Toraj;Zarch, Seyed Hossein Hosseini;Eshghpour, Majid;Kermani, Hamed
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.43 no.2
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    • pp.88-93
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    • 2017
  • Objectives: Any change in maxilla and mandible position can alter the upper airway, and any decrease in the upper airway can cause sleep disorders. Thus, it is necessary to assess airway changes after repositioning of the maxilla and mandible during orthognathic surgery. The purpose of this study was to evaluate linear and volumetric changes in the upper airway after bimaxillary surgery to correct class III malocclusion via cone-beam computed tomography (CBCT) and to identify correlations between linear and volumetric changes. Materials and Methods: This was a prospective cohort study. CBCTs from 10 class III patients were evaluated before surgery and three months after. The Wilcoxon one-sample test was used to evaluate the differences in measurements before and after surgery. Spearman's rank correlation coefficient was used to test the correlation between linear and volumetric changes. Results: The results show that the nasopharyngeal space increased significantly, and that this increase correlated with degree of maxillary advancement. No significant changes were found in volumes before and after surgery. A correlation was found between linear and volumetric oropharyngeal changes. Conclusion: Bimaxillary surgical correction of class III malocclusion did not cause statistically significant changes in the posterior airway space.