• Title/Summary/Keyword: geometrical characteristics

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A Study on Formation of Void Space by Geometric Method and Environment-friendly Characteristics in Contemporary Housing (현대주거의 기하조작에 의한 보이드 공간의 생성과 친환경적 특성에 관한 연구)

  • Lee, Dong-Ki
    • Journal of the Korean housing association
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    • v.21 no.6
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    • pp.131-141
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    • 2010
  • This study is aimed to grasp the spatial characteristics exhibited in the modern housing architecture from the aspect of a geometrical manipulation, which transforms basic geometrical shapes and persue the formative diversity, to identify and verify the various characteristics of spatial structure in modern housing architecture. In this regard, this paper analyze and identify the influences of the void spaces that are created by geometrical manipulations on housing architecture, in terms of morphological and environmental aspects. Theoretical approaches define the concept of geometrical manipulation according to the characteristics of residence and examine the spatial features of void spaces. Additionally, case studies result in the classification of void spaces that are created by geometrical manipulation. Furthermore, to understand environment-friendly characteristics of the void space, the researcher elicited the factors that can affect environment friendly housing from previous studies, and analyzed their correlation between those factors and the void spaces that are classified.

Thermal post-buckling behavior of GPLRMF cylindrical shells with initial geometrical imperfection

  • Yi-Wen Zhang;Gui-Lin She;Lei-Lei Gan;Yin-Ping Li
    • Geomechanics and Engineering
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    • v.32 no.6
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    • pp.615-625
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    • 2023
  • Initial geometrical imperfection is an important factor affecting the structural characteristics of plate and shell structures. Studying the effect of geometrical imperfection on the structural characteristics of cylindrical shell is beneficial to explore the thermal post-buckling response characteristics of cylindrical shell. Therefore, we devote to investigating the thermal post-buckling behavior of graphene platelets reinforced mental foam (GPLRMF) cylindrical shells with geometrical imperfection. The properties of GPLRMF material with considering three types of graphene platelets (GPLs) distribution patterns are introduced firstly. Subsequently, based on Donnell nonlinear shell theory, the governing equations of cylindrical shell are derived according to Eulerian-Lagrange equations. Taking into account two different boundary conditions namely simply supported (S-S) and clamped supported (C-S), the Galerkin principle is used to solve the governing equations. Finally, the impact of initial geometrical imperfections, the GPLs distribution types, the porosity distribution types, the porosity coefficient as well as the GPLs mass fraction on the thermal post-buckling response of the cylindrical shells are analyzed.

Relationship Between Flat End-mill Shape and Geometrical Characteristics in Side Walls Generated by End-milling Process (엔드밀링 공정에 의하여 생성된 측벽의 기하학적 특성과 평엔드밀 형상 사이의 관계)

  • Kim, Kang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.1
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    • pp.95-103
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    • 2015
  • This paper presents the effects of the tool shape on the geometrical characteristics of flat end-milled side walls. A tool shape is characterized by such parameters as helix angle, number of cutting edges, and diameter. The geometrical characteristics of the side walls are represented by the surface profiles in the feed and axial directions, which are orthogonal to each other. The geometrical defects in each direction are estimated based on the instantaneous apparent cutting areas, which are represented by the interference area between the tool and workpiece and that between the cutting edge and workpiece. It is confirmed that a geometrical defect in the feed direction is formed when the tool leaves the workpiece and the curvature of the tool path changes. Defects in the axial direction are also found in the side walls, except for the defect zone in the feed direction. An up-cut using an end-mill with a steeper helix angle, a greater number of cutting edges, and a smaller diameter are thus found to improve the geometrical accuracy of end-milled side walls.

Effect of Tool Approaching Path on the Shape of Cylindrical Hole in a Milling Process (공구접근 경로가 밀링 가공된 원통 구멍 형상에 미치는 영향)

  • Kim, Kwang-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.3 no.4
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    • pp.50-55
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    • 2004
  • Because of the development in mold industries, the geometrical form accuracy of the milled surface is getting more and more important. It has been known that the geometrical form accuracy is affected by machine conditions, cutting conditions, tool conditions and tool path and so on. Among them, the tool approaching path causes the change in material removal per tooth at the end of each machining cycle. And, this change generates the geometrical form error around the region where the tool engages the workpiece initially. So, it is impossible to eliminate the geometrical error caused by the tool approaching path. Thus, characteristics of this geometrical error are studied analytically and experimentally to minimize this region.

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Predicting Lamina Yield from Logs of Different Diameters for Cross Laminated Timber Production

  • Jeong, Gi Young;Lee, Jun-Jae;Yeo, Hwanmyeong;Lee, So Sun
    • Journal of the Korean Wood Science and Technology
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    • v.44 no.6
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    • pp.809-820
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    • 2016
  • The goal of this study was to predict lamina yield from logs of different diameter for production of cross laminated timber. Log characteristics of red pine (Pinus densiflora) and Japanese cedar (Cryptomeria japonica), including diameter, length, volume, and defects were used for statistical and geometrical analyses, along with the lamina characteristics, including width, thickness, and defects. Based on the data obtained, the strong factors influencing the yield and grade of lamina from the two species were statistically evaluated. A geometrical approach was used for analysis of the yield from logs of given diameters. Statistical analysis showed that lamina yield was dependent on target lamina size but the grade of lamina was not related to any of the log characteristics. The suggested yield equations from the geometrical approach indicated an accuracy of less than 20% difference.

Effect of Geometrical Parameters on Spray Characteristics of Shear/Swirl Coaxial Injector (전단/와류동축 분사기의 형상학적 변수에 따른 분무특성 영향)

  • Cheolwoong Kang;Shinwoo Lee;Hadong Jung;Kyubok Ahn
    • Journal of ILASS-Korea
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    • v.29 no.3
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    • pp.112-123
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    • 2024
  • In this study, a cold-flow test was conducted under ambient conditions to investigate the impact of key geometrical parameters on the spray characteristics of coaxial injectors. Two types of injectors were examined: shear coaxial and swirl coaxial. The primary geometrical variables considered were the recess length and taper angle. The effects of each geometric parameter on the pressure drop, discharge coefficient, breakup length, and spray angle were analyzed. In the swirl coaxial injector, the recess length and the presence of taper affected the discharge coefficient more than in the shear coaxial injector. In terms of breakup length and spray angle, the shear coaxial injector and the swirl coaxial injector showed different results, due to the combination of the jet or swirl injection of the oxidizer and the geometrical variables of the injector. The breakup length and spray angle of the swirl coaxial injector were superior to those of the shear coaxial injector. It is expected that the swirl coaxial injector will have better combustion performance in hot-firing tests.

The Effects of Geometrical Imperfections on the Dynamic Characteristics of a Tapered Roller Bearing Cage (테이퍼 롤러 베어링 케이지의 불완전성이 통특성에 미치는 영향)

  • Ahn, Tae-Kil;Park, Jang-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.464-469
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    • 2019
  • Tapered roller bearings are used widely in vans, trucks, and trains because they can support the vehicle in a stable manner even under a heavy load. The cage of a tapered roller bearing maintains the gap between the rollers, which prevents friction wear and suppresses heating. If the cage is severely deformed due to resonance, the roller may not be able to roll smoothly and even leave the cage. Consequently, it is very important to analyze the dynamic characteristics of the cage for reliable performance of a bearing. The cage essentially has geometrical tolerance in the manufacturing process. In this paper, the effects of those geometrical imperfections on the dynamic characteristics of the cage were investigated. As a result, natural frequency separation occurred near the natural frequency of the ideal cage due to geometrical imperfections. In addition, the interval was proportional to the magnitude of the geometric error, and the interval increased with increasing mode number.

Measurement of Geometrical Characteristics of Fruit by Image Processing System (화상처리(畵像處理) 시스템을 이용(利用)한 과일의 기하학적(幾何學的) 특성(特性) 측정(測定))

  • Noh, S.H.;Ryu, K.H.;Kim, Y.W.
    • Journal of Biosystems Engineering
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    • v.15 no.1
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    • pp.23-32
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    • 1990
  • Geometrical characteristics of fruit including perimeter, projected area and length of minor and major axis were calculated by computer programs to be used in fruit sorting by image processing system. The results are summerized as follows. 1. A program calculating perimeter, projected area, and length of minor and major axis by edge detection and chain code was developed. 2. Geometrical characteristics of given figures were calculated to verify the program and the discrepancies from the measured values were about 5%. 3. Regression models for estimating volums of apples were developed and regression coefficients for each variety were found. 4. Abnormal apples could be recognized by comparing the ratio of minor axis to major axis and the standard value was proposed.

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Feature Extraction of Face and Face Elements Using Projection and Correction of Incline (투영과 기울기 보정을 이용한 얼굴 및 얼굴 요소의 특징 추출)

  • 김진태;김동욱;오정수
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.3
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    • pp.499-505
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    • 2003
  • This paper proposes methods to extract face elements and facial characteristics points for face recognition. We select a candidate region of the face elements with geometrical information between them inside the extracted face region with skin color and extract them using their inherent features. The facial characteristics to be applied to face recognition is expressed with geometrical relation such as distance and angle between the extracted face elements. Experiment results shows good performance to extract of face elements.

A Study on the Characteristics of the Wheel/Roller Contact Geometry (차륜/궤조륜 기하학적 접촉특성에 관한 연구)

  • Hur, Hyun-Moo
    • Journal of the Korean Society for Railway
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    • v.9 no.5 s.36
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    • pp.618-623
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    • 2006
  • Understanding the contact between wheel and rail is a starting point in railway vehicle dynamic research area and especially analysis for the contact geometry between wheel and rail is important. On the one hand, the critical speed as the natural characteristics of rolling-stock is generally tested on the roller rig. The geometrical characteristics of the wheel/roller contact on the roller rig are different from these of the general wheel/rail contact because the longitudinal radius of roller is not infinite compared with rail. Thus, in this paper we developed the algorithm to analyze the wheel/roller contact geometry of our roller rig which is constructed now and analyzed the difference between whee/roller contact and wheel/rail contact. In conclusion, we found that the yaw motion of wheelset and the roller radius influence the geometrical contact parameters in wheel flange contact area.