• Title/Summary/Keyword: irregular wall

Search Result 192, Processing Time 0.03 seconds

Design Modification of the Stamping Die for the Improvement of Surface Quality of the Front End Module Carrier Upper Member (프런트 엔드 모듈 캐리어 어퍼 부재의 면품질 개선을 위한 금형설계 변경)

  • Kim S. H.
    • Transactions of Materials Processing
    • /
    • v.14 no.2 s.74
    • /
    • pp.153-159
    • /
    • 2005
  • Design modification of the stamping die for the upper member of a front end module carrier is carried out in order to improve the surface quality of the final product. The small inferiority induced by wrinkling near the wall of the upper member has been inspected after the draw-forming process. The finite element analysis is pursued with the whole geometry in order to consider the complicated shape. The simulation shows that the excess metal is developed by the irregular contact of the blank the tool and it remains after the final stroke. This paper proposes two guidelines for the modification. One is to add the draw-bead near the critical region in order to increase the draw-in force. The other is to modify the tool shape such as the forming shape at the wall in order to absorb the excess metal before the final stroke. Simulation results show that the proposed guidelines both guarantee the improved surface quality.

Improvement of Feeling Quality of a Stamped Member for an Autobody with the Finite Element Analysis (유한요소해석을 이용한 자동차용 박판부재의 감성품질 개선)

  • Kim S. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2004.10a
    • /
    • pp.252-255
    • /
    • 2004
  • Design modification of the stamping die for the upper member of a front end module carrier is carried out in order to improve the feeling qualify of the final product. The small inferiority induced by wrinkling near the wall of the FEM upper member has been inspected after the draw-forming process. The finite element simulation shows that the excess metal is developed by the irregular contact of the blank the tool and it remains after the final stroke. This paper proposes two guidelines for the modification: one is to add the draw-bead; and the other is to modify the tool shape such as the forming shape at the wall. Simulation results show that the proposed guidelines both guarantee the improved feeling quality.

  • PDF

Studies on infection rate and histopathological findings of canine heartworms in Inchon city (인천 지역 사육견의 심장사상충 감염률 및 병리조직학적 연구)

  • 이성모;황현순;김종훈
    • Korean Journal of Veterinary Service
    • /
    • v.22 no.1
    • /
    • pp.25-35
    • /
    • 1999
  • The prevalence of canine heartworm(Dirofilaria immitis) infection in 150 mixed-breed dogs(male : 54, female : 96) from February to December 1997 was investigated by using antigen test kit(ICT $GOLD^{TM}$ HW, Synbiotics, USA) based on immunochromatographic assay in Inchon city. Also, gross and histopathological findings of an antigen positive dog were carried out. The results were summarized as follows ; 1. Four dogs were positive from 150 tested dogs(2.7%). They were all more than 2 years old and infection rates in male and outdoor dogs was higher than those in female and indoor, respectively. Species of infected dogs were Pug(2) , German Sheperd(1) and Great-dane (1). 2. Regional infection rates were closely related with housing system in the city. 3. Pathological findings of antigen-positive dog was excessive enlargement, congestion and hemorrhage of lung and D immitis in heart and histologically hemosiderin, hypertrophy of pulmonary alveoli wall and irregular hypertrophy of pulmonary artery inner wall. Microfilaria was observed in pulmonary artery and arteriole, ventricle and splenic artery.

  • PDF

Numerical Analysis on the Collision Behaviors of in-flight Droplets During Gas Atomization (가스 분무 시 비행 액적의 충돌 현상에 관한 수치적 고찰)

  • Seok, Hyun Kwang
    • Korean Journal of Metals and Materials
    • /
    • v.46 no.8
    • /
    • pp.506-515
    • /
    • 2008
  • Recently, it is exceedingly required to produce metal powders with tailored shape and phase altogether in order to fabricate high performance functional parts such as magnetic core or electro-magnetic noise suppressor for high frequency usage. Therefore, the collision phenomena of in-flight droplets against chamber wall or neighboring in-flight droplets each other is investigated by a computational method in order to get useful information about how to design the atomizing system and how to tailor process parameters not to make irregular-shaped powders during gas atomization process. As a results, smaller powders, lower melt temperature are known to be favorable for droplets not to collide against chamber wall. In additions, powders of narrower size distribution range, lower droplet generation rate, lower melt temperature, lower gas velocity are desirable to prevent droplet-collisions against neighboring in-flight droplets.

A Study on Structural Maintenance of 'Old Wall' Designated as National Registered Cultural Heritage (국가등록문화재로 지정된 옛 담장의 정비 양상)

  • So, Hyun-Su;Jeong, Myeong-Seok
    • Journal of the Korean Institute of Traditional Landscape Architecture
    • /
    • v.41 no.1
    • /
    • pp.21-34
    • /
    • 2023
  • This study identified the materials and construction methods of 'Old Wall' in 13 villages which were designated as National Registered Cultural Heritage at the time of designation and examined the their structural changes based on field survey. The results are as follows: First, the 'Old Wall' consisted of 10 Soil-Stone Wall and 5 Stone Wall. At the time of designation, Stone Wall, which was built irregularly by dry-construction of natural stones, is similar in shape, but Soil-Stone Wall showed difference by the construction method of making used stones, joints, and faces. Second, the study extracted the changes of 'Old Wall' by repair and examined the changes of construction methods as well as the substitution and addition of materials of structure. The wall-roof was built with cement roof-tile and asbestos slate which have the advantage improve durability and cost-effectiveness. In addition, tile-mouth soil was added to korean traditional roof-tile to prevent rainwater from flowing in. Besides, to improve constructional convenience, the natural stone of the wall-body was replaced with blast stone, float stone and cut stone. Cement block, cement brick and cement mortar were frequently used to repair as well. As Soil-Stone Wall was transformed from irregular pattern-construction to comb pattern-construction and wet-construction was changed to dry-construction, it caused landscape and structural problems. Also, the layer of cement mortar applied to wall-foundation blocked the flow of rainwater that was induced by dry-construction of natural stones. Third, the study regarded that the problem with the repair of 'Old Wall' may occur as it is located in living space, because the owner of the wall could repair for the minor damages without technical knowledge. In addition, it is difficult for repair companies in charge of maintenance of Cultural Heritage to supply local materials, and it is differential construction specifications are not applied.

A Wrapping Method for Inserting Titanium Micro-Mesh Implants in the Reconstruction of Blowout Fractures

  • Choi, Tae Joon;Burm, Jin Sik;Yang, Won Yong;Kang, Sang Yoon
    • Archives of Plastic Surgery
    • /
    • v.43 no.1
    • /
    • pp.84-87
    • /
    • 2016
  • Titanium micro-mesh implants are widely used in orbital wall reconstructions because they have several advantageous characteristics. However, the rough and irregular marginal spurs of the cut edges of the titanium mesh sheet impede the efficacious and minimally traumatic insertion of the implant, because these spurs may catch or hook the orbital soft tissue, skin, or conjunctiva during the insertion procedure. In order to prevent this problem, we developed an easy method of inserting a titanium micro-mesh, in which it is wrapped with the aseptic transparent plastic film that is used to pack surgical instruments or is attached to one side of the inner suture package. Fifty-four patients underwent orbital wall reconstruction using a transconjunctival or transcutaneous approach. The wrapped implant was easily inserted without catching or injuring the orbital soft tissue, skin, or conjunctiva. In most cases, the implant was inserted in one attempt. Postoperative computed tomographic scans showed excellent placement of the titanium micro-mesh and adequate anatomic reconstruction of the orbital walls. This wrapping insertion method may be useful for making the insertion of titanium micro-mesh implants in the reconstruction of orbital wall fractures easier and less traumatic.

Studies on Structure of Pericarp in Ginseng (Panax ginseng C.A. Meyer) Fruit (인삼과실의 과피구조에 관한 연구)

  • Yu, Seong-Cheol;Jeong, Byeong-Gap;Kim, U-Gap
    • Journal of Ginseng Research
    • /
    • v.13 no.1
    • /
    • pp.71-78
    • /
    • 1989
  • The structural changes in the pericarp of Panax ginseng fruit cells are studied during maturation periods. The pericarp can be divided into exocarp, mesocarp and endocarp. The exocarp consists of one layer of epidermal cells which is covered by a thin cuticle and hypodermal cells. A central vacuole and peripheral cytoplasm are observed in the exocarp and mesocarp. Also, irregular wall arrangement are observed during the differentiation. The endocarp is clearly marked off from the others by secondaw wall thickening and lignification. Secretory materials produced by the Golgi complex and rough endoplasmic reticulum vesicles appear to accumulated in the cell wall. These secretory materials are considered major components of the seed coat during the differentiation.

  • PDF

Ultrastructure of Cymbidium Leaf Tissue Systemically Infected with Odontoglossum Ringspot Virus (오돈토글로썸 윤문 바이러스에 감염된 Cymbidium 잎조직의 미세구조)

  • Ryu, Ki-Hyun;Kim, Woo-Kap;Park, Won-Mok
    • Applied Microscopy
    • /
    • v.24 no.3
    • /
    • pp.46-54
    • /
    • 1994
  • In ultrathin section of the tissue of odontoglossum ringspot virus (ORSV)-infected Cymbidium goeringii Reichenbach, ORSV particles appeared as bundles of irregular aggregates of various length which were called stacked plates or rounded plates. Virus particles were found in the cytoplasm in electron clear zones and they also found between cell wall and plasma membrane. They mainly clustered in parallel aggregates and sometimes oriented randomly. The X-bodies and paramural bodies were observed near the cell membrane and these contained vacuole-like cavities. The cell wall of infected tissue expanded largely. Some chloroplast in ORSV infected cell was irregular. No virus particle was present in mitochondria, nuclei, vacuoles, vesicles or other organelles. The plasmodesmata slightly enlarged, and virus-associated granules were present around it.

  • PDF

Inverse Radiation Analysis of a Two-Dimensional Irregular Geometry Using Unstructured Triangular Meshes (비정렬 삼각 격자를 이용한 2 차원 비직교 형상에서의 역복사 해석)

  • Yi, Kyung-Joo;Baek, Seung-Wook;Kim, Man-Young
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.35 no.6
    • /
    • pp.561-567
    • /
    • 2011
  • The inverse radiation analysis of a two-dimensional irregular configuration using unstructured triangular meshes is presented. In this study, an enclosure filled with an absorbing, emitting and scattering medium with diffusely emitting and reflecting opaque boundaries is considered. The finite volume method is applied to solve the radiative transfer equation in order to simulate the measured incident radiation values which are used as input data for the inverse analysis. The conjugate gradient method is adopted for the estimation of wall emissivities by minimizing the objective function at each iteration step. To verify the performance of the unstructured grid system, we compare the results with those using a structured grid system for the two-dimensional lopsided shape. The effect of measurement errors on the estimation accuracy is also investigated.

Pushover Analysis of Reinforced Concrete Wall-Frame Structures Using Equivalent Column Model (등가 기둥 모델을 이용한 철근콘크리트 전단벽-골조 구조물의 푸쉬오버 해석)

  • Kim, Yong Joon;Han, Arum;Kim, Seung Nam;Yu, Eunjong
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.18 no.1
    • /
    • pp.53-61
    • /
    • 2014
  • RC shear wall sections which have irregular shapes such as T, ㄱ, ㄷ sections are typically used in low-rise buildings in Korea. Pushover analysis of building containing such members costs a lot of computation time and needs professional knowledge since it requires complicated modeling and, sometimes, fails to converge. In this study, a method using an equivalent column element for the shear wall is proposed. The equivalent column element consists of an elastic column, an inelastic rotational spring, and rigid beams. The inelastic properties of the rotational spring represent the nonlinear behavior of the shearwall and are obtained from the section analysis results and moment distribution for the member. The use of an axial force to compensate the difference in the axial deformation between the equivalent column element and the actual shear wall is also proposed. The proposed method is applied for the pushover analysis of a 5- story shear wall-frame building and the results are compared with ones using the fiber elements. The comparison shows that the inelastic behavior at the same drift was comparable. However, the performance points estimated using the pushover curves showed some deviations, which seem to be caused by the differences of estimated yield point and damping ratios.