• Title/Summary/Keyword: Head shape

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A Study for Preventing Folding Defect of the Common Rail Pipe in Heading Process (커먼레일 파이프 헤딩공정의 접힘결함 방지에 관한 연구)

  • Song, Myung-Jun;Woo, Ta-Kwan;Jung, Sung-Yuen;Hur, Kwan-Do;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.1
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    • pp.25-32
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    • 2010
  • With the latest automobile technology, though the third generation common rail system requires high injection pressures up to 1,800bar, the next generation diesel engine is expected to require more higher pressures than the third generation. The common rail pipe requires higher strength because it is one of the parts in the common rail system, which is influenced directly by fuel under high pressure. Preform design is very important for preventing head of the common rail pipe from folding in the heading process. In this study, die angle, curvature, outer diameter of die and length of trapped part are selected as main parameters to obtain best preform shape minimizing radius of folding. Therefore optimal design is carried out by finite element analysis and Taguchi method through main parameters. Results of the finite element analysis have good agreements with those of the experiments in the actual field.

Characteristics of temporomandibular joint structures after mandibular condyle fractures revealed by magnetic resonance imaging

  • Kim, Bong Chul;Lee, Yoon Chang;Cha, Hyung Seok;Lee, Sang-Hwy
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.38
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    • pp.24.1-24.7
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    • 2016
  • Background: This study aimed to evaluate the structural changes of temporomandibular joint immediately after condylar fractures with magnetic resonance imaging (MRI). Method: We evaluated 34 subjects of condylar fractures with MRI. The position, shape, and signal intensity of the condyle, disc, and retrodiscal tissue were analyzed with MR images. Results: Immediately after trauma, the disc was displaced with the fractured segment in almost all cases. And, the changes of signal intensity at the retrodiscal tissue were found but less related to the degree of fracture displacement. And, the high signals were observed almost at all fractured joint spaces and even at some contralateral joints. Conclusions: The displaced disc as well as the increased signal intensity of the joint space, condylar head, and retrodiscal tissue demands more attention to prevent the possible sequela of joint.

GROWTH OF MANDIBULAR CONDYLAR CARTILAGE OF THE RAT IN VITRO (하악두연골의 성장에 관한 시험관적 연구)

  • Lee, Dong-Yul;Nahm, Dong-Seok
    • The korean journal of orthodontics
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    • v.22 no.2 s.37
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    • pp.309-325
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    • 1992
  • The purpose of this study was to evaluate the effect of intrinsic factor and extrinsic factor for growth of the mandibular condylar cartilage of 4 day-old rats in a serum-free medium for 1, 4, 7, 14 days. They were compared with normal growth in vivo and with growth of spheno-occipital synchondrosis in serum-free medium. The cellular kinetics of cartilages were evaluated by auto-radiography of tritiated thymidine. 1. Condylar cartilage was enlarged with rounded head on day 14 of experiment while in vivo the rounded-headed shape changed into functionally flattened appearance. 2. On day 14 of experiment, a severe reduction of the proliferative zone and a considerable increase of the hypertrophic zone were observed while in normal control group endochondrol bone formation and bone marrow were observed. 3. The proliferative activity in the proliferative zone of condylar cartilage detected by $^3H-thymidine$ incorporation was lower than that of normal control group and decreased more than that of spheno-occipital synchondrosis, but it continued during the 14 days of culture. 4. The continued maintenance of condylar cartilage and morphologic change were disturbed in this culture system, but cell division within the proliferative zone was continued and probably linked to intrinsic factor.

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A Study on the Design for Fashion Cultural Product with Formative Beauty in Traditional Ornament Unique to Korean Females (전통 여성 수식의 형태미를 활용한 패션문화상품 디자인 연구)

  • Kim, Sun Young;Kwon, Jin
    • Journal of the Korean Society of Costume
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    • v.63 no.3
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    • pp.33-45
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    • 2013
  • This work developed the basic motive design utilizing the physical beauty of the traditional ornaments used uniquely by Korean females and suggested some textile designs and fashion cultural product designs. As a research method, computer design programs Adobe Illustrator CS3 and Adobe Photoshop CS3 were used as well as literature examination. The motive was mainly based on the dwiggoji and ddeoljam, which are female ornaments. The formative shape in woman ornaments was classified into four kinds: plant, animal, geometry, and hybrid. The hybrid type was divided further into such combinations as plant, animal, and geometry, which came up with 8 fundamental motives for design development in total. With regard to the basic motive design, the coordinated concept was adopted with a combination of traditional taste and contemporary taste in harmony for the expression of delicate image on the condition that the basic format in female ornament is maintained. Textile design was processed with symmetry, rotation, repeat, and overlap as fundamental motive. As to the design for fashion cultural products, design mapping was proposed for neckties, handbags, clutches, shirts, and one-pieces. Utility and beauty in the traditional ornaments unique to Korean women could be recognized once again through this work. This work also assured the possibility for the endless improvement as a design development motive with originality.

A study on the Assyrian Costume

  • Kim, Moon-Ja
    • Journal of Fashion Business
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    • v.14 no.3
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    • pp.1-19
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    • 2010
  • The Assyrians usually wore two types - the tunic and the shawl. These two types were worn alone, or in combination and changes were introduced by varying the proportions of the tunic or shawl. The tunic appeared to be of the sleeves are short and reaching to the ankles or shortened to knee length according to the rank. Assyrian shawl pattern can be divided into five distinct styless. Many of the styles were suitable for costumes to wear in religious plays and pageants. Fringed shawls were the trademark of forma1 Assyrian costume. The usual badge of rank was a long fringed shawl. Intermediate rank wore shawl with short fringes and lower grade wore no shawl at all. The military costume was comparative uniformity : conical helmets was regarded as Scythic in character, short, fringed tunics, wide belts or helmet, round caps and long tunics covered in metal scales, belted at the waist. Assyrian woman costume was the long tunic with fringed hem and a long fringed shawl or was a plaid tunic and wide belt over it. They wore gold crown and horned Cap and tiara, ugal (head-dress) and the most ordinary earrings were the drop and the cross shape and necklace was made of the coloured stones and bracelets ended with heads of animal was regarded as Scythy style or adorned with a rosette at the centre.

A Study on the Effects of Intake Port Eccentricity on the In-cylinder Swirl Ratio Characteristics in a 4 Valve Diesel Engine (4밸브 디젤기관의 흡기포트 편심이 실린더 내 선회비 특성에 끼치는 영향에 관한 연구)

  • 이지근;강신재;노병준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.5
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    • pp.157-169
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    • 1997
  • The effects of intake port eccentricity on the characteristics of in-cylinder swirl ratio in a 4-valve diesel engine having the two intake ports; one is a helical intake port and the other is a tangential intake port were investigated by using the ISM(impulse swirl meter) in steady flow test rig. Swirl ratio($R_s$) and mean flow coefficient($C_{f(mean)}$) with valve eccentricity ratio($N_y$) and axial distance(Z/B) were measured. As the results from this experiment, the characteristics of in-cylinder swirl ratio formed by a 4-valve cylinder head were largely affected by intake port eccentricity. There is a difference in the mass flowrate through the two intake ports, and the mass flowrate through the tangential intake port is 19% more than that of the helical intake port. Therefore, we could know that the effects of the mass flowrate ratio through each intake port besides intake port shape should be conidered.

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Mix Design for Pervious Recycled Aggregate Concrete

  • Sriravindrarajah, Rasiah;Wang, Neo Derek Huai;Ervin, Lai Jian Wen
    • International Journal of Concrete Structures and Materials
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    • v.6 no.4
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    • pp.239-246
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    • 2012
  • Pervious concrete is a tailored-property concrete with high water permeability which allow the passage of water to flow through easily through the existing interconnected large pore structure. This paper reports the results of an experimental investigation into the development of pervious concrete with reduced cement content and recycled concrete aggregate for sustainable permeable pavement construction. High fineness ground granulated blast furnace slag was used to replace up to 70 % cement by weight. The properties of the pervious concrete were evaluated by determining the compressive strength at 7 and 28 days, void content and water permeability under falling head. The compressive strength of pervious concrete increased with a reduction in the maximum aggregate size from 20 to 13 mm. The relationship between 28-day compressive strength and porosity for pervious concrete was adversely affected by the use of recycled concrete aggregate instead of natural aggregate. However, the binder materials type, age, aggregate size and test specimen shape had marginal effect on the strength-porosity relationship. The results also showed that the water permeability of pervious concrete is primarily influenced by the porosity and not affected by the use of recycled concrete aggregate in place of natural aggregate. The empirical inter-relationships developed among porosity, compressive strength and water permeability could be used in the mix design of pervious concrete with either natural or recycled concrete aggregates to meet the specification requirements of compressive strength and water permeability.

A Study on woman's hair fashions of Tang and Song Dynasty (당대와 송대의 여자장식에 관한 고찰)

  • 이순자
    • Journal of the Korean Society of Costume
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    • v.35
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    • pp.67-89
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    • 1997
  • During thousands of years the people of china have not only created the brilliant cul-ture with a world reputation but also brought about an abundant treasury of paramountly beautiful hairdo fashions beyond comparison. Hair styles are an important symbol of the ma-terial and cultural civilization of a certain his-torical period. In Dang Dynasty the country was unified the economy was properous and the political situation was relatively stable. These spelt the solid foundation on which the rich and colourful varieties in the hair styles of women emerged. The numerous hair fashions in Tang Dynasty woman folk could be summed up into three catagories-high bun hanging bun and flat bun. Of course like the garments hair fashions are also the marks for the social status of the women in the feudal society. The hairstyle of the women of the Song Dynasty still followed the fashion of the later period of the Tang Dynasty the high bun be-ing the favoured style. To dress this type of high bun switches were generally used sometimes fashioned in to switch buns of various shapes coiled directly on top of the head. Women from rich families however usually had hairpins and combs made into the shape of flowers birds phoenixes of butterflies to be pinned on top of the buns.

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ANALYSES ON FLOW FIELDS AND PERFORMANCE OF A CROSS-FLOW FAN WITH VARIOUS SETTING ANGLES OF A STABILIZER

  • Kim D. W.;Kim H. S.;Park S. K.;Kim Youn J
    • Journal of computational fluids engineering
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    • v.10 no.1
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    • pp.107-112
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    • 2005
  • A cross-flow fan is generally used on the region within the low static pressure difference and the high flow rate. It relatively makes high dynamic pressure at low rotating speed because a working fluid passes through an impeller blade twice and blades have a forward curved shape. At off-design points, there are a rapid pressure head reduction, a noise increase and an unsteady flow. Those phenomena are remarkably influenced by the setting angle of a stabilizer. Therefore, it should be considered how the setting angle of a stabilizer affects on the performance and the flow fields of a cross-flow fan. It is also required to investigate the effect of the volumetric flow rate before occurring stall. Two-dimensional, unsteady governing equations are solved using a commercial code, STAR-CD, which uses FVM. PISO algorithm, sliding grid system and standard k - ε turbulence model are also adopted. Pressure and velocity profiles with various setting angles are graphically depicted. Furthermore, the meridional velocity profiles around the impeller are plotted with different flow rates for a given rotating speed.

suspension dynamics of HDD for high track density (고트랙밀도 HDD 서스펜션의 동특성 해석)

  • Kim, Chung-Joo;Chun, Jeong-Il;Byun, Yong-Kyu;Ro, Kwang-Choon;Chung, Chung-Choo;Jeong, Tae-Gun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.11
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    • pp.1885-1895
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    • 1997
  • As track density needs to increase to the order of 10, 000 tpi, the suspension has become a critical component in hard disk drives. One of the main obstacles to attain high track density is the structural resonances of the suspension in lateral direction. We investigate the suspension dynamics through the experimental modal analysis and the finite element method. An LDV (Laser Doppler Vibrometer) is employed to measure the response of the suspension which is excited by a shaker and an inpulse hammer for the free condition and the loaded condition, respectively. After comparing the experimental and numerical results, we study how the initial geometry of the bend region affects the suspension dynamics. It is found that the natural frequency of the sway mode decreases as the bend ratio and the bend angle increase. The shape of torsional mode changes as the mass of a slider increases, resulting in a local decrease in the natural frequency.