• Title/Summary/Keyword: wrap

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A Finite Element Modeling and Analyses of Laser Tailor-Welded Automotive Body (레이저 용접 차체의 유한 요소 모델링과 성형해석)

  • 김헌영;최광용;김관회;조원석
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.31-36
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    • 1997
  • Various methods of finite element modeling for welded part are examined and the stamping simulation of automotive body is presented by using the explicit finite element code PAM-STAMPTM. The process of stamping simulation is suggested step by step, and then the gravity, binder wrap, forming, trimming and springback of front door inner are analyzed. It shows good agreements with real product in the aspects of deformed shape and failure area. The door inner with laser-tailor welded blank is simulated, in which deformed shape, movement of welde line and formability are predicted.

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A Study on the Religious Costume in Ancient Mesopotamia (고대 메소포타미아 종교 복식에 관한 연구)

  • 임상임;류보영
    • Journal of the Korean Society of Costume
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    • v.50 no.8
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    • pp.113-128
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    • 2000
  • This essay examines the costumes for gods and priests in ancient Mesopotamia as they are depicted in various documents and artifacts of the period, and it is part of an ongoing project that studies the process in which the religious costumes, the means of religious communication, of ancient Mesopotamia had evolved. The study shows that the religious costunmes in ancient Mesopotamia have following characteristics. 1. The costumes for gods are the same as those for men, including warp-around skirts, tierd skirts, shawls, and tunics. However, there are some differences : costumes for gods include such distinguishing features as aprons and long tassels. 2. Both wear stylized headpieces that indicate their divinity and have long hair and long beard. 3. As for shoes, the Sumerian and Babilonian gods go barefoot, but the militant Assyrian gods wear sandals. 4. Sumerian and Babilonian figures do not have much, but the Assyrian gods wear various ornaments including earrings and bracelets that emphasize their muscular physique. 5. Priests wear weird skirts or wrap-around skirts but no top. They have shaved hair to indicate their role as purifiers, but some of them have long beards.

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Investigation on Heat Transfer in Scroll Compressor (스크롤 압축기 내부에서의 열전달에 대한 연구)

  • Jang, Ki-Tae;Jeong, Sang-Kwon
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.199-204
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    • 2003
  • In the present study, the compression process in scroll compressor was simulated in consideration of flow leakage and heat transfer. Tangential and radial leakages of the refrigerant between the scrolls were considered as nozzle flow. The experiment was first conducted with a scroll compressor for automobile air conditioning system and R134a as a refrigerant. Temperature and pressure were measured at the suction and discharge ports of the compressor to determine the thermodynamic states of the refrigerant flow. Temperature distribution of the scroll with the involute angle was also measured by thermocouples that were installed inside the scroll. Measured temperature distribution was compared with the numerical results. From this result, the thermal effect of mechanical contact was found to be important in heat transfer of the compression process.

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Effect of Polymer Wrapping on the Properties of ABS/MWNT Nanocomposites (고분자 래핑(wrapping)에 의한 전처리가 ABS/MWNT 나노복합체의 물성에 미치는 영향)

  • Kim, Jung-Hwan;Min, Byung-Gil
    • Textile Coloration and Finishing
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    • v.22 no.1
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    • pp.37-42
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    • 2010
  • ABS/MWNT nanocomposites were prepared by using MWNT wrapped with SAN through melt compounding. Effect of wrapping of MWNT by SAN on the morphology, mechanical and electrical properties of ABS/MWNT were analyzed. It was found that SAN could wrap MWNT effectively indicated by the increased thickness after wrapping, which is presumably due to helical structure of polyacrylonitrile component in a block copolymer of SAN. MWNT was observed to be dispersed more evenly in ABS matrix by SAN wrapping, which resulted in improved tensile properties of the composites. On the other hand, there was little effect on the impact strength and electrical properties of ABS having inherently high impact strength.

Stamping Analyses of Laser Welded Door Inner and Die Design (레이저 용접 도어 인너의 성형해석과 금형설계)

  • 김헌영;신용승;김관희;조원석
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.10a
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    • pp.65-71
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    • 1997
  • Computer simulations and test trials are carried out to get the optimal conditions about the stamping die design of the tailor laser welded automotive door inner. Firstly, the stamping process including gravity deflection, bead calibration, binder wrap, forming and spring back, are analyzed by the computer simulation. The results of simulation shows good correspondance with those of test trial under the same conditions. The variables of parametric study which will be investigated in the simulation and test trials, are determined form the results of the first run. The formability under the various conditions is evaluated, which are the initial postion of blank, blank holding force, corner radius and the shape of drawbead. Finally, well controled sound product without fracture, wrinkling and excessive weldline movement is obtained.

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Development of Fixture for Reducing Errors in Registration of 3D Laser Measuring System (Registration 오차감소를 위한 3차원 비접촉식 측정용 Fixture 개발)

  • Kim Yeun Sul;Jin Young Ju;Lee Hi Koan;Yang Gyun Eui
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.10 s.175
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    • pp.107-113
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    • 2005
  • This paper presents a method to reduce errors in registration, which is used in transformation coordinate system of the multiple measuring data. In general, the ICP algorithms and feature-based approaches are used for registration. In order to measure wrap-around object, it is necessary to change the scanning direction or set-up of the object. A fixture is made to reduce registration errors caused by inaccurate center point of tooling balls, providing the more accurate registration method. And, the motorized fixture controls rotation and tilting to get precise the measuring data and registration. The proposed motorized fixture and registration method have advantages in accurate registration and precise measurement, compared with the conventional methods.

Development of an Automated Ordering and Packing Units for Sweet Persimmons (단감 자동정렬 포장장치 개발)

  • 김진현;최중섭;김태욱
    • Journal of Biosystems Engineering
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    • v.27 no.5
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    • pp.399-408
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    • 2002
  • The sweet persimmons are producted 227,394 tons per year in Korea. They are preserved at cold storage after wrapping them in packing vinyl to maintain quality. Using conventional handwork, a skillful worker could probably produce only 1,000 packings a day. Hiring many skilled-labors to wrap sweet persimmons in packing vinyl seems to be difficult because of the recent rural crisis. Therefore, it was necessary to be developed for the automated ordering and packing unit that is convenient and laborsaving. This study were summarized as follows : Success rates of 99%, 100%, and 88% were observed for ordering parts, sealing and cutting films, and sealing films in the inlet part, respectively. The time required per 1 cycle was 16 seconds and the developed unit performed 225 cycles an hour. The unit showed an ability of 1,125 pieces per hour. Therefore, the productivity was 10 times greater than that of skillful handwork.

Freshness Keeping of Shiitake Mushroom by Vacuum Cooling (진공예냉에 의한 표고버섯의 선도 연장)

  • Kim, Byeong-Sam;Nahmgung, Bae;Kim, Oui-Woung;Kim, Dong-Chul
    • Korean Journal of Food Science and Technology
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    • v.27 no.6
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    • pp.852-859
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    • 1995
  • Vacuum cooling were carried out for freshness keeping of shiitake mushroom. Shiitake mushroom was cooled within 30 minutes from $20.5^{\circ}C$ to $0.5^{\circ}C$ by vacuum cooling, and then temperature drop of $6.6^{\circ}C$ per weight loss of 1% was taken place during precooling. Weight loss, surface discoloration and softening were reduced by precooling. Judging from organoleptic properties such as cap opening, discoloration, texture and off-flavor, shelf-life of precooled mushroom was lengthed by 20% than that of non-treated mushrooms. Considering effect of packing material on freshness of shiitake mushroom after precooling, weight retention, hardness and organoleptic properties of mushroom packed with PVC wrap were superior to those packed in carton box.

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Flow Characteristics of the Main Nozzle with different Acceleration Tube and Diameter in an Air-Jet Loom (에어젯트 직기에서 가속관 직경변화에 따른 주노즐의 유동특성)

  • Jeong, S.Y.;Kim, K.H.
    • Journal of ILASS-Korea
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    • v.8 no.2
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    • pp.16-23
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    • 2003
  • The Air-jet loom represents a major step in the development of shutterless weaving due to its ability to weave a wide range of yarns at high speeds. The Air-jet weaving involvers, inserting a pre-measured length of yam through the wrap, is sheds by meads of compressed air. The analysis of air flow characteristic of the main nozzle and acceleration tube is required for the loom performance. h this paper We examined the effect of the main nozzle with different acceleration tubes as well as diameters. And also, we compared the performance of straight type tube with laval type tube and of according to be suction hole on the acceleration tube, respectively.

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Thermal-Hydraulic Analysis of A Wire-Spacer Fuel Assembly

  • Ahmad, Imteyaz;Kim, Kwang-Yong
    • 유체기계공업학회:학술대회논문집
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    • 2004.12a
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    • pp.473-478
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    • 2004
  • This work presents the Thermal Hydraulic analysis has been performed for a 19-pin wire-spacer fuel assembly using three-dimensional Reynolds-averaged Navier-Stokes equations. SST model is used as a turbulence closure. The whole fuel assembly has been analyzed for one period of the wire-spacer using periodic boundary condition at inlet and outlet of the calculation domain. The overall results far a preliminary calculation show a good agreement with the experimental observations. It has been found that the major unidirectional flows are the axial velocity in sub-channels and the peripheral sweeping flows and the velocities are found to be following a cyclic path of period equal to the wire-wrap pitch. The temperature is found to be maximum in the central region and also, there exist a radial temperature gradient between the fuel rods. The major advantage of performing this kind of analysis is the prediction of thermal-hydraulic behavior of a fuel assembly with much ease.

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